The present invention relates to a toothbrush.
　This application claims priority based on Japanese Patent Application No. 2018-246151 filed in Japan on December 27, 2018, the contents of which are incorporated herein by reference.
Background technology
[0002]
　While the percentage of people at the age of 80 who have 20 teeth is about 50%, the percentage of elderly caries (root caries) is increasing. Root caries is caries of dentin exposed by gingival recession, but since dentin has a higher composition ratio of organic components than enamel, caries progresses quickly. One of the causes of the gingival recession is overbrushing, in which brushing is performed with a brushing pressure larger than the appropriate value.
[0003]
　Since the brushing pressure is defined by the load / flocking area, reducing the brushing pressure can be achieved by at least one of reducing the load and increasing the flocking area. To reduce the load, a toothbrush with specifications designed to tilt the neck part above the flocked surface in advance so that the neck part bends when brushing and the neck part becomes straight when brushing, and a toothbrush with a small diameter. There are commercially available toothbrushes with soft specifications using the above, and toothbrushes with specifications that make it difficult for force to be applied to the flocked portion by arranging the center of gravity of the grip portion closer to the rear end of the handle. Further, for increasing the flocked area, a toothbrush or the like having a wide head width is commercially available. However, in these specifications, although it is possible to reduce the brushing pressure, it is difficult to make all users recognize the appropriate brushing pressure at the same level and control the brushing pressure.
[0004]
　In addition, although the proper brushing method is instructed at the dentist's office, it is difficult to deal with it by oneself because it is not clear how much force is applied. It turns out that there are not a few users who do not.
[0005]
　Therefore, as a means for making the user recognize the appropriate brushing pressure, for example, the toothbrush disclosed in Patent Document 1 can be mentioned. In Patent Document 1, the head support portion between the head portion and the grip portion is formed of an elastic material such as a stainless steel sheet that can be inverted so that the head portion warps when brushing with a predetermined pressing force or more. Toothbrushes are disclosed.
[0006]
　In the toothbrush disclosed in Patent Document 1, the head portion is warped, so that the user can recognize that the appropriate brushing pressure has been exceeded.
Prior art literature
Patent documents
[0007]
Patent Document 1: Japanese Patent No. 4118067
Outline of the invention
Problems to be solved by the invention
[0008]
　However, with the toothbrush disclosed in Patent Document 1 described above, it is only possible to recognize by hand that the appropriate brushing pressure has been exceeded, and it is sufficient to more reliably recognize that the appropriate brushing pressure has been exceeded. No.
[0009]
　The present invention has been made in consideration of the above points, and an object of the present invention is to provide a toothbrush capable of more reliably recognizing an appropriate brushing pressure.
Means to solve problems
[0010]
　According to the first aspect of the present invention, a head portion provided on the tip side in the long axis direction and having a flocked surface, a grip portion arranged on the rear end side of the head portion, and the flocked surface and the grip portion. A sound that has a neck portion arranged between the two, and generates a click sound due to deformation when the external force in the first direction orthogonal to the flocked surface exceeds the threshold value on the rear end side of the flocked surface. A toothbrush characterized by having a generator is provided.
[0011]
　Further, in the toothbrush according to one aspect of the present invention, the sound generated from the sound generating portion is characterized in that the A characteristic sound pressure level is 30 dB or more and the frequency is 100 Hz or more and 10,000 Hz or less.
[0012]
　Further, in the toothbrush according to one aspect of the present invention, the sound generating portion is the head to the back surface side opposite to the flocked surface in the first direction due to the external force exceeding the threshold value. It is characterized in that it is provided with an inversion portion that generates the click sound when it jumps, buckles, and inverts with the displacement of the portion.
[0013]
　Further, in the toothbrush according to one aspect of the present invention, the sound generating portion has a first region on the tip side of the sound generating portion and a second region on the rear end side of the sound generating portion. It is characterized by having an elastically deformed portion that is connected and elastically deforms at least up to the external force that generates the click sound.
[0014]
　Further, in the toothbrush according to one aspect of the present invention, the elastically deformed portion and the inverted portion are arranged with a gap in the second direction orthogonal to the first direction and the major axis direction, respectively. It is characterized by.
[0015]
　Further, in the toothbrush according to one aspect of the present invention, the elastically deformed portion has a hard portion formed of a hard resin and a soft portion formed of a soft resin and covering the hard portion, and the inverted portion. Is made of a hard resin having a flexural modulus of 1500 MPa or more.
[0016]
　Further, in the toothbrush according to one aspect of the present invention, the thickness of the elastically deformed portion in the first direction is 6 mm or more and 12 mm or less, and the sound generating portion is located on both ends in the long axis direction. It is formed of a hard resin and has a support portion that supports both ends of the elastically deformed portion and the reversing portion in the major axis direction, and the reversing portion is a center point of the thickness of the supporting portion in the first direction. It is characterized in that it is inverted in a range of 1% or more and 30% or less of the thickness in the first direction of the elastically deformed portion about a line segment connecting the two.
[0017]
　Further, in the toothbrush according to one aspect of the present invention, the inverted portion has a convex shape on the back surface side when the external force in the first direction is equal to or less than the threshold value, and the inverted portion has a convex shape on the back surface side with the support portion. The distance between the intersection and the apex of the convex shape in the first direction is 0.5 mm or more and 4.2 mm or less.
[0018]
　Further, in the toothbrush according to one aspect of the present invention, the inverted portion has a groove portion extending in the second direction on at least one of the flocked surface side and the back surface side in the region including the apex of the convex shape. It is characterized by.
[0019]
　Further, in the toothbrush according to one aspect of the present invention, the minimum thickness of the inverted portion in the region provided with the groove portion in the first direction is 0.1 mm or more and 1.0 mm or less. do.
[0020]
　Further, in the toothbrush according to one aspect of the present invention, the thickness of the hard portion in the first direction is 1.0 mm or more and 2.0 mm or less.
The invention's effect
[0021]
　INDUSTRIAL APPLICABILITY The present invention can provide a toothbrush capable of more reliably recognizing an appropriate brushing pressure.
A brief description of the drawing
[0022]
FIG. 1 is a view showing an embodiment of the present invention and is a front view of the toothbrush 1.
FIG. 2 is a cross-sectional view of the toothbrush 1 cut along a plane including a center in the width direction.
FIG. 3 is a cross-sectional view of the sound generating portion 70 cut in a plane parallel to the thickness direction and the width direction.
FIG. 4 is a cross-sectional view of the sound generating portion 70 cut along a plane parallel to the thickness direction and the long axis direction.
FIG. 5 is a partial front view of the vicinity of the sound generating portion 70 in the hard portion 70H.
FIG. 6 is a partial side view of the vicinity of the sound generating portion 70 in the hard portion 70H.
FIG. 7 is a cross-sectional view of the sound generating portion 70 cut along a plane parallel to the thickness direction and the major axis direction for explaining that the inverted portion is inverted.
Embodiment for carrying out the invention
[0023]
　Hereinafter, embodiments of the toothbrush of the present invention will be described with reference to FIGS. 1 to 7.
　It should be noted that the following embodiments show one aspect of the present invention, do not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of ​​the present invention. Further, in the following drawings, in order to make each configuration easy to understand, the scale and number of each structure are different from the actual structure. Further, in the following description, the side orthogonal to the flocked surface in the side view will be the vertical direction, the flocked surface side will be the upper side, and the back side opposite to the flocked surface will be the lower side. In addition, the vertical direction, the upper side, and the lower side are names used only for explanation, and do not limit the actual positional relationship and direction in the present invention.
[0024]
　FIG. 1 is a front view of the toothbrush 1. FIG. 2 is a cross-sectional view of the toothbrush 1 cut along a plane including the center in the width direction (vertical direction in FIG. 1).
[0025]
　The toothbrush 1 of the present embodiment has a head portion 10 arranged on the tip side in the long axis direction (hereinafter, simply referred to as the tip side) and having hair bundles (not shown) implanted, and the length of the head portion 10. The neck portion 20 extended to the rear end side in the axial direction (hereinafter, simply referred to as the rear end side), the sound generating portion 70 extending to the rear end side of the neck portion 20, and the rear end of the sound generating portion 70. A grip portion 30 extended to the side (hereinafter, the head portion 10, the neck portion 20, the grip portion 30, and the sound generating portion 70 are collectively referred to as a handle body 2) is provided.
[0026]
　The toothbrush 1 of the present embodiment is a molded body in which a hard portion H formed of a hard resin and a soft portion E formed of a soft resin are integrally molded. The hard portion H constitutes at least a part of each of the head portion 10, the neck portion 20, the grip portion 30, and the sound generating portion 70. The soft portion E constitutes a part of each of the grip portion 30 and the sound generating portion 70 (details will be described later).
[0027]
[Head portion 10] The
　head portion 10 has a flocked surface 11 on one side in the thickness direction (direction orthogonal to the paper surface in FIG. 1). Hereinafter, the flocked surface 11 side in the thickness direction will be the front side in the front direction, the side opposite to the flocked surface will be the back side, and the direction orthogonal to the thickness direction and the long axis direction will be the width direction (or as appropriate). , Side direction). A plurality of flocked holes 12 are formed on the flocked surface 11. Hair follicles (not shown) are planted in the hair-planting holes 12.
[0028]
　The width of the head portion 10, that is, the length in the width direction parallel to the flocked surface 11 on the front side and orthogonal to the long axis direction (hereinafter, simply referred to as width) is not particularly limited, and is, for example, 7 mm or more and 13 mm or less. Is preferable. When it is at least the above lower limit value, a sufficient area for planting hair bundles can be secured, and when it is at least the above upper limit value, operability in the oral cavity can be further improved.
[0029]
　The length of the head portion 10 in the major axis direction (hereinafter, simply referred to as a length) is not particularly limited, and is preferably 10 mm or more and 33 mm or less, for example. When the length of the head portion 10 is not less than the above lower limit value, a sufficient area for planting hair bundles can be secured, and when it is not more than the above upper limit value, the operability in the oral cavity can be further enhanced. The boundary between the neck portion 20 and the head portion 10 in the major axis direction in the present embodiment is a position where the width of the neck portion 20 is the minimum value from the neck portion 20 toward the head portion 10.
[0030]
　The length of the head portion 10 in the thickness direction (hereinafter, simply referred to as thickness) can be determined in consideration of the material and the like, and is preferably 2.0 mm or more and 4.0 mm or less. When the thickness of the head portion 10 is at least the above lower limit value, the strength of the head portion 10 can be further increased. When the thickness of the head portion 10 is not more than the above upper limit value, the reachability to the back of the molars can be enhanced and the operability in the oral cavity can be further enhanced.
[0031]
　A hair bundle is a bundle of a plurality of hairs. The length (hair length) from the flocked surface 11 to the tip of the hair bundle can be determined in consideration of the hair waist and the like required for the hair bundle, and is, for example, 6 to 13 mm. All hair bundles may have the same hair length or may be different from each other.
[0032]
　The thickness (hair bundle diameter) of the hair bundle can be determined in consideration of the hair waist and the like required for the hair bundle, and is, for example, 1 to 3 mm. All hair bundles may have the same hair bundle diameter or may be different from each other.
[0033]
　As the hair that constitutes the hair bundle, for example, the diameter of the hair gradually decreases toward the tip of the hair, and the tip of the hair is sharpened (tapered hair). Examples include the same hair (straight hair). Examples of straight hair include those having a flat surface substantially parallel to the flocked surface 11 and those having hemispherically rounded hair tips.
[0034]
　The material of the hair is, for example, polyamide such as 6-12 nylon (6-12NY), 6-10 nylon (6-10NY), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT). ), Polyester such as polyethylene terephthalate (PEN) and polybutylene terephthalate (PBN), polyolefins such as polypropylene (PP), polyolefin-based elastomers, and elastomer resins such as styrene-based elastomers. These resin materials can be used alone or in combination of two or more. Further, as the hair, a polyester hair having a multi-core structure having a core portion and at least one layer or more of a sheath portion provided on the outside of the core portion can be mentioned.
[0035]
　The cross-sectional shape of the hair is not particularly limited, and may be a circular shape such as a perfect circle or an oval shape, a polygonal shape, a star shape, a three-leaf clover shape, a four-leaf clover shape, or the like. The cross-sectional shapes of all hairs may be the same or different.
[0036]
　The thickness of the hair can be determined in consideration of the material and the like, and when the cross section is circular, it is, for example, 6 to 9 mil (1 mil = 1/1000 inch = 0.025 mm). Further, in consideration of usability, brushing feeling, cleaning effect, durability and the like, a plurality of hairs having different thicknesses may be used in any combination.
[0037]
[Neck portion 20]
　The length of the neck portion 20 is preferably 40 mm or more and 70 mm or less in terms of operability.
　As an example, the width of the neck portion 20 is formed so as to gradually increase from the position where the minimum value is obtained to the rear end side. The neck portion 20 in the present embodiment is formed so as to gradually increase from the position where the width becomes the minimum value toward the rear end side. Further, the neck portion 20 is formed so that the thickness gradually increases from the position where the thickness becomes the minimum toward the rear end side.
[0038]
　The width and thickness of the neck portion 20 at the minimum position are preferably 3.0 mm or more and 4.5 mm or less. If the width and thickness of the neck portion 20 at the minimum position is equal to or more than the above lower limit value, the strength of the neck portion 20 can be further increased. And the operability in the oral cavity can be further improved. The width and thickness of the neck portion 20 formed so as to gradually increase toward the rear end side from the position where the minimum value is obtained can be appropriately determined in consideration of the material and the like.
[0039]
　The front side of the neck portion 20 in the side view is inclined toward the front side toward the rear end side. The back side of the neck portion 20 in the side view is inclined toward the back side toward the rear end side. The neck portion 20 is inclined in a direction in which the distance from the center in the width direction increases toward the rear end side in the front view.
[0040]
　The boundary between the neck portion 20 and the sound generating portion 70 in the present embodiment is the position of the tip of the neck side 20 where the elastically deformed portion 90 described later is provided. Here, the width expands from the neck portion 20 toward the grip portion 30 with an arcuate contour in both front view and side view, and the position of the center of curvature of the arc coincides with the changed position in the long axis direction. There is. More specifically, the boundary between the neck portion 20 and the sound generating portion 70 is the position in the major axis direction in which the center of curvature changes from the outside of the arcuate contour to the center side in the width direction in the front view shown in FIG. Match. Further, the boundary between the neck portion 20 and the sound generating portion 70 coincides with the position in the major axis direction in which the center of curvature changes from the outside of the arcuate contour to the center side in the thickness direction in the side view shown in FIG. ing.
[0041]
[Grip portion 30] The
　grip portion 30 is arranged along the long axis direction. As shown in FIG. 1, the length of the grip portion 30 in the width direction gradually narrows from the boundary with the sound generating portion 70 toward the rear end side, and then extends to a substantially constant length. As shown in FIG. 2, the length of the grip portion 30 in the thickness direction gradually narrows from the boundary with the sound generating portion 70 toward the rear end side, and then extends to a substantially constant length.
[0042]
　The boundary between the sound generating portion 70 and the grip portion 30 in the present embodiment is the position of the tip of the grip portion side 30 where the elastically deformed portion 90 described later is provided. Here, the width is reduced from the sound generating portion 70 toward the grip portion side 30 by an arcuate contour in both front view and side view, and the position of the center of curvature of the arc is changed to the position in the long axis direction. I am doing it. More specifically, the boundary between the sound generating portion 70 and the grip portion 30 is a position in the long axis direction in which the center of curvature changes from the center side in the width direction to the outside of the arcuate contour in the front view shown in FIG. Is consistent with. Further, the boundary between the sound generating portion 70 and the grip portion 30 coincides with the position in the major axis direction in which the center of curvature changes from the center side in the thickness direction to the outside of the arcuate contour in the side view shown in FIG. There is.
[0043]
　The length in the width direction of the grip portion 30 gradually narrows from the boundary with the sound generating portion 70 toward the rear end side, and then becomes a substantially constant length, and the position in the major axis direction and the thickness direction of the grip portion 30. The positions in the long axis direction become substantially constant after the length of the sound gradually narrows from the boundary with the sound generating portion 70 toward the rear end side, and is the same.
[0044]
　The grip portion 30 has a soft portion 31E in the center in the width direction on the front side. The soft portion 31E constitutes a part of the soft portion E. The soft portion 31E gradually narrows toward the rear end side from the boundary with the sound generating portion 70 in the front view, and then extends at a substantially constant length. In front view, the side edge of the soft portion 31E and the lateral edge of the grip portion 30 in the width direction are formed at a substantially constant distance.
[0045]
　The grip portion 30 has a hard portion 30H. The hard portion 30H constitutes a part of the hard portion H. The hard portion 30H has a recess 31H in which a part of the soft portion 31E is embedded on the front side. The recess 31H gradually narrows from the boundary with the sound generating portion 70 toward the rear end side in the front view, and then extends at a substantially constant length.
[0046]
　A part of the soft portion 31E protrudes from the hard portion 30H exposed on the front side. The other soft portion 31E is substantially flush with the hard portion 30H exposed on the front side.
[0047]
　The grip portion 30 has a soft portion 32E in the center in the width direction on the back surface side (see FIGS. 1 and 2). The soft portion 32E constitutes a part of the soft portion E. The soft portion 32E has substantially the same outer contour as the outer contour of the soft portion 31E when viewed from the front. That is, the soft portion 32E gradually narrows toward the rear end side from the boundary with the sound generating portion 70, and then extends at a substantially constant length. In the rear view, the side edge of the soft portion 32E and the lateral edge of the grip portion 30 in the width direction are formed at a substantially constant distance.
[0048]
　The hard portion 30H has a recess 32H (see FIG. 2) in which a part of the soft portion 32E is embedded on the back surface side. The recess 32H gradually narrows from the boundary with the sound generating portion 70 toward the rear end side in the rear view, and then extends at a substantially constant length.
[0049]
　A part of the soft portion 32E protrudes from the hard portion 30H exposed on the back surface side. The other soft portion 32E is substantially flush with the hard portion 30H exposed on the front side.
[0050]
　Since the soft portion 31E is provided on the front side of the grip portion 30 and the soft portion 32E is provided on the back side, the grip property when gripping the grip portion 30 is improved.
[0051]
[Sound generation unit 70] The
　sound generation unit 70 is deformed to generate a click sound when the external force in the first direction orthogonal to the flocked surface 11 exceeds the threshold value. As shown in FIG. 1, the sound generating portion 70 includes a reversing portion 80 and an elastic deformation portion 90 that connect a neck portion 20 on the tip side of the sound generating portion 70 and a grip portion 30 on the rear end side of the sound generating portion 70. And have.
[0052]
　FIG. 3 is a cross-sectional view of the sound generating portion 70 cut in a plane parallel to the thickness direction and the width direction. FIG. 4 is a cross-sectional view of the sound generating portion 70 cut along a plane parallel to the thickness direction and the long axis direction.
　As shown in FIG. 3, the elastically deformed portions 90 are provided with gaps S on both sides of the reversing portion 80 in the width direction. The gap S is formed by a through hole K penetrating in the thickness direction. As shown in FIG. 1, the through hole K is formed in a rectangular shape in a plan view extending in the long axis direction.
[0053]
　隙間Ｓを設けることで、周囲の構造と干渉せずに反転部８０が反転可能となる（反転しやすくなる）。また、（干渉しないので）反転部８０の変形が弾性変形部の変形に追従しないため、反転部８０と弾性変形部９０の機能的役割（後述）を独立させることができる。これにより、例えば以下の効果を得るための設計の自由度を高めることができる。例えば、後述する反転部８０が反転する際の振動・音を明瞭に発生させることができる。また、例えば、しきい値に至るまでの反発力を、変位量に比例して上昇させることが可能となり、特にしきい値近傍においても前記比例関係を保つことが可能となる（反発力の上昇度合が緩くならない）。これにより、上限となる圧力に達する変位量までの領域は、使用者が想定する圧力がそのまま反発力に反映されるため、ブラッシング荷重を適切に制御することができる。もし、しきい値に至る近傍で反発力の上昇度合が徐々に緩くなる設定の場合、使用者は意図せず上限付近の圧力でブラッシングし続ける可能性がある。また、隙間Ｓは反転部８０の厚さ方向両側にも連通させれば、前記効果がさらに向上する。隙間Ｓを厚さ方向に広げることで、ブラッシング時に刷毛部（用毛）に負荷する荷重のベクトルと隙間の開口する方向、さらに反転部８０と弾性変形部９０とが変形する方向が並行となり（図７参照）、反転による振動・音の発生をブラッシング荷重と連動させることが容易となる。更に、隙間Ｓを貫通孔Ｋによって正面側と背面側とを貫通させれば、例えば、ブラッシング時の荷重に対する、ハブラシ骨格の撓み機能を担う弾性変形部９０の可動領域を更に拡大することができる（撓みに伴う、表面での引張り挙動、裏面での圧縮挙動が阻害されにくい）。弾性変形部９０と反転部８０との間に貫通孔Ｋが存在しない場合には、弾性変形部９０の可動領域が狭くなる。この場合、反転部８０が反転する契機を適切な荷重範囲で与えられず、適切な荷重範囲に達する前に反転部８０が反転すること、あるいは適切な荷重範囲であっても反転しないという事態が想定される。これに対して、弾性変形部９０と反転部８０との間に貫通孔Ｋを設けることにより、後述する反転部８０が反転する「しきい値」を、より細かい範囲で制御することができる。なお、隙間Sは厚さ方向に貫通しなくても良く、例えば弾性変形部９０の内部に前記長軸方向に延びる閉鎖された空洞により形成されても良い。また、正面側または背面側に開口する窪み（後述）により形成されても良い。
[0054]
　Each elastically deformed portion 90 has a hard portion 90H and a soft portion 90E. As shown in FIG. 1, the hard portion 90H and the soft portion 90E connect the rear end of the neck portion 20 and the front end of the grip portion 30. As shown in FIGS. 3 and 4, between the pair of elastically deformed portions 90, a recess (recess) 71 that opens on the front side and a recess (recess) 72 that opens on the back side are provided. The bottoms of the recess 71 and the recess 72 on both ends in the width direction are connected to the through hole K, respectively. An inverted portion 80 is exposed and provided at the bottom of the recess 71 and the center in the width direction in the recess 72. By providing the recesses 71 and 72, for example, the movable region of the elastically deformed portion that bears the bending function of the toothbrush skeleton with respect to the load during brushing can be further expanded, and the bending anisotropy in the thickness direction can be improved. The recesses between the pair of elastically deformed portions 90 may not penetrate in the thickness direction, and may be opened in only one of the thickness directions. Further, for example, a closed cavity extending in the long axis direction may be formed inside the elastic deformation portion 90, and the cavity may be sandwiched in the center to form a pair of elastic deformation portions in the width direction.
[0055]
　In the pair of elastically deformed portions 90, the ends of the soft portions 90E in the major axis direction are connected to each other in the width direction on both the front side and the back surface side. The soft portions 90E of the pair of elastically deformed portions 90 are provided around the oval recesses 71 and 72 when viewed from the front. The rear end side of the soft portion 90E is connected to the soft portion 31E of the grip portion 30.
[0056]
　Since the soft portion 90E is connected in the width direction on both the front end side and the rear end side of the elastically deformed portion 90, stress is less likely to be concentrated on the end of the hinge structure even if the inversion is repeated, and the bending is less likely to occur. Further, since the soft portion 90E is connected in the width direction, the amount of heat possessed by the soft resin (elastomer) during injection molding increases, so that the adhesiveness between the neck portion 20 and the sound generating portion 70 (the neck portion 20 and the elastically deformed portion 90) becomes poor. It will increase. Further, the soft portion 90E is connected in the width direction on both the front end side and the rear end side of the elastically deformed portion 90, so that the anisotropy in the sound generating portion 70 is increased. For example, the pair of elastically deformed portions 90 moves during brushing. On the other hand, it is possible to bend without twisting in the thickness direction.
[0057]
　FIG. 5 is a partial front view of the sound generating portion 70 around the hard portion 70H. FIG. 6 is a partial side view of the sound generating portion 70 around the hard portion 70H.
　As shown in FIG. 5, the hard portion 70H is formed in a rectangular shape in a plan view connecting the hard portion 20H which is the head portion 20 and the hard portion 30H of the grip portion 30 in the long axis direction.
[0058]
　The hard portion 70H includes a support portion 77H that supports the end portion on the tip end side of the pair of hard portions 90H and the end portion on the tip end side of the reversing portion 80 and connects them in the width direction, and the end on the rear end side of the pair of hard portions 90H. It has a support portion 78H that supports and connects the end portion on the rear end side of the portion and the reversing portion 80 in the width direction.
[0059]
　As shown in FIG. 6, the front end side of the hard portion 70H (support portion 77H) is connected to the hard portion 20H by a curved surface 73H having an arc shape in a side view. The rear end side of the front side of the hard portion 70H (support portion 78H) is connected to the hard portion 30H by a curved surface 74H having an arc shape in a side view. The arc centers of the curved surfaces 73H and 74H are located on the front side of the hard portion 70H in the side view. The tip end side of the hard portion 70H on the back surface side is connected to the hard portion 20H by a curved surface 75H having an arc shape in a side view. The rear end side of the hard portion 70H on the back surface side is connected to the hard portion 30H by a curved surface 76H having an arc shape in a side view. The arc centers of the curved surfaces 75H and 76H are located on the back side of the hard portion 70H in the side view.
[0060]
　When the curved surfaces 73H to 76H do not exist, stress may be concentrated on the boundary between the front end side of the hard portion 70H and the hard portion 20H and the boundary between the rear end side of the hard portion 70H and the hard portion 30H. On the other hand, the presence of the curved surfaces 73H to 76H alleviates the concentrated stress. Further, due to the presence of the curved surfaces 73H to 76H, both the elastic deforming portion 90 and the front end side and the rear end side of the reversing portion 80 can be flexibly deformed (the elastic deforming portion 90 that triggers the reversal). The degree of deformation can be sensed in more detail).
[0061]
　The hard portion 70H has through holes 73 provided on both sides of the reversing portion 80 in the width direction. The through holes 73 extend in the major axis direction, respectively. The length of the through hole 73 in the major axis direction is such that the distal end side end portion of the through hole 73 is separated from the hard portion 20H and the rear end side end portion of the through hole 73 is separated from the hard portion 30H. As shown in FIG. 3, of the through holes 73, a soft portion 90E is provided near the hard portion 90H in the width direction, and a through hole K is formed near the inverted portion 80 in the width direction.
[0062]
　In the hard portion 70H, 90H is arranged on both sides in the width direction with the reversing portion 80 as the center via the through holes 73, so that even if a load is applied and the elastic deforming portion 90 is deformed, the shape of the reversing portion 80 is formed. Can be maintained. When the hard portion H constituting the toothbrush 1 over the entire length is bent, the reversing portion 80 of the sound generating portion 70 is inverted in an attempt to release the accumulated strain energy. For example, when the hard portion 70H is connected to the neck portion 20 and the grip portion 30 only by the reversing portion 80, the energy cannot be stored and the portion is immediately inverted. When the reversing portion 80 is integrally injection-molded with the first region A1 and the second region A2, which will be described later, the neck portion 20, the grip portion 30, and the hard portion 70H, the accumulated strain energy is efficiently transferred to the reversing portion. Can be communicated.
[0063]
　The hard portion 90H is formed outside the hard portion 70H in the width direction with respect to the through hole 73. As shown in FIG. 3, the hard portion 90H has a substantially rectangular cross-sectional shape. The hard portion 90H is embedded in the soft portion 90E. Since the hard portion 90H is embedded in the soft portion 90E, the stress applied to the hard portion 90H can be relaxed from the viewpoint of strength. Further, the elastic behavior of the elastically deformed portion 90 can be controlled from the viewpoint of the degree of bending of the toothbrush 1 with respect to the load. Further, the bending anisotropy of the sensing portion 70 is increased, and for example, it is possible to bend the elastic deformation portion 90 without twisting in the thickness direction with respect to the movement during brushing.
[0064]
　Examples of the material of the hard portion H include a resin having a flexural modulus (JIS7171) of 1500 MPa or more and 3500 MPa or less, and examples thereof include polyacetal resin (POM). The flexural modulus of the hard portion H is more preferably 2000 MPa or more and 3500 MPa or less. By using a material having a high elastic modulus (for example, POM), even if the shape is thin or thin, when an excessive load is applied, jumping buckling occurs, and vibration and sound are exhibited. Further, by using a material having a high elastic modulus, it is possible to quickly return to the initial state (a state in which the bending of the elastically deformed portion 90 is released) after buckling occurs.
[0065]
　As the material of the soft portion E, a material having a shore hardness A of 90 or less is preferable, and a shore hardness A is preferably 90 or less, in that the load when jumping buckling occurs is close to the recommended brushing load value. Those of 50 to 80 are more preferable. Examples of the soft resin include elastomers (for example, olefin-based elastomers, styrene-based elastomers, polyester-based elastomers, polyurethane-based thermoplastic elastomers, etc.) and silicones. A styrene-based elastomer is preferable because it has excellent miscibility with a polyacetal resin.
[0066]
　As shown in FIG. 5, the reversing portion 80 extends in the long axis direction in the front view, and the first region A1 on the distal end side of the through hole 73 in the hard portion 70H and the second region A1 on the rear end side of the through hole 73. It is connected to the area A2. The reversing portion 80 is in a first stable state (hereinafter, first state) shown in FIG. 4 in which an external force to the back surface side is not applied to the head portion 10 (or an external force equal to or lower than a predetermined threshold value described later is applied). In (referred to as), it is formed in a substantially V shape in a side view that gradually inclines toward the back surface side from both ends in the long axis direction toward the center. That is, in the first state, the reversing portion 80 is formed in a convex shape on the back surface side where the center in the major axis direction is the apex.
[0067]
　For example, when an external force to the back surface side is applied to the head portion 10 while the grip portion 30 is gripped, if the magnitude of the external force is equal to or less than a predetermined threshold value, the elastic deformation portion 90 and the reversing portion 80 have an external force. Elastically deforms according to the size of. When an external force is applied, bending energy is accumulated in the reversing portion 80 as the elastic deformation portion 90 bends.
[0068]
　When the magnitude of the external force exceeds a predetermined threshold value, the elastically deformed portion 90 elastically deforms according to the magnitude of the external force exceeding the threshold value. On the other hand, when the magnitude of the external force exceeds a predetermined threshold value, the reversing portion 80 jumps, buckles and reverses when the neck portion 20 is deformed, as shown by the alternate long and short dash line in FIG. 7, and the second It becomes the stable state of 2 (hereinafter referred to as the second state). In the second state, the reversing portion 80 is reversed in a direction in which it gradually inclines toward the front side toward the center and becomes a substantially inverted V-shape in side view. In the second state, the inverting portion 80 is formed in a convex shape on the front side where the center in the major axis direction is the apex.
[0069]
　That is, when the magnitude of the external force exceeds a predetermined threshold value, the elastically deformed portion 90 elastically deforms with the displacement of the head portion 10, so that the bending strength in the sound generating portion 70 is guaranteed. The reversing portion 80 jumps from the first state, buckles and reverses, and becomes the second state. Further, since the through hole K is provided between the reversing portion 80 and the elastically deforming portion 90, the reversing portion 80 and the elastically deforming portion 90 can be deformed independently of each other, and the reversing portion 80 can be easily inverted. Become. That is, since the through hole K is provided when a brushing load is applied, the reversing portion 80 can be flexed after only the elastic member 90 is first flexed without hindering each other's deformation behavior. It should be noted that the space between the reversing portion 80 and the elastically deforming portion 90 does not necessarily have to penetrate, and a gap S may be formed.
[0070]
　When the reversing portion 80 jumps, buckles, and flips, a click sound is generated by the vibration in which the accumulated bending energy is released at once. Therefore, the user who grips the grip portion 30 applies to the back surface of the head portion 10. It is possible to detect that the external force to the side exceeds the threshold value and is in an overbrushing state.
[0071]
　Since the reversing portion 80 is provided so as to be exposed in the space of the recess 71 opening on the front side and the recess 72 opening on the back side, the click sound generated when the reversing portion 80 is inverted is used in a state where the loss is small. Reachable. Therefore, the user can easily hear the click sound when brushing. In order to make it easier for the user to hear the click sound, the position of the reversing portion 80 is preferably close to the head portion 10 close to the user's ear.
[0072]
　Since the loudness of human hearing depends on both the sound pressure level and the frequency, it is necessary to consider both the sound pressure level and the frequency in order to make the sound sufficiently audible during brushing.
[0073]
　Since the sound is easily heard during brushing, the click sound generated from the sound generating unit 70 preferably has an A-weighted sound pressure level of 30 dB or more, and more preferably 40 dB or more. As the sound pressure level becomes higher, the frequency that humans can hear becomes wider, and even low frequencies (for example, 100 Hz) and high frequencies (for example, 10000 Hz) can be heard by humans.
[0074]
　Since the sound is easily heard during brushing, the frequency of the click sound generated from the sound generating unit 70 is preferably 100 Hz or more and 10,000 Hz or less, and more preferably 500 Hz or more and 6500 Hz or less. If the frequency of the click sound generated from the sound generation unit 70 is less than 100 Hz, or if it exceeds 10000 Hz, it may be difficult to hear the click sound.
[0075]
　The reversing portion 80 has a groove portion 81 in the center in the long axis direction on the front side, that is, in a region including the apex of the convex shape. The reversing portion 80 has a groove portion 82 in the center in the long axis direction on the back surface side, that is, in a region including the apex of the convex shape. The grooves 81 and 82 extend in the width direction. The groove portion 81 is formed in an arc shape in a side view in which the center of the arc is arranged on the front side. The groove portion 82 is formed in an arc shape in a side view in which the center of the arc is arranged on the back surface side. When the groove portions 81 and 82 are not provided in the reversing portion 80, strain is uniformly generated in the entire reversing portion 80, and jumping buckling is unlikely to occur. On the other hand, when the grooves 81 and 82 are provided in the reversing portion 80, strain is concentrated in the grooves 81 and 82, and jumping buckling is likely to occur.
[0076]
　The radius of the arc-shaped grooves 81 and 82 when viewed from the side is preferably 1 mm or more and 2 mm or less. If the radius of the groove portions 81 and 82 is less than 1 mm, the reversing portion 80 may not be inverted. When the radius of the grooves 81 and 82 exceeds 2 mm, it may be difficult to detect the overbrushing state because the vibration of the reversing portion 80 at the time of reversing is small and a sufficient click sound is not generated. ..
[0077]
　As for the depth of the groove portions 81 and 82, it is preferable that the groove portion 81 is deeper than the groove portion 82. When the groove portion 82 is deeper than the groove portion 81, the reversing portion 80 is less likely to be inverted even when the magnitude of the external force exceeds a predetermined threshold value. Further, when the groove portion 81 is deeper than the groove portion 82, the reversing portion 80 can be guided so as to be more likely to jump and buckle on the front side.
　It should be noted that the configuration may be such that both the groove portions 81 and 82 are not provided, but the groove portion 82 is not provided and only the groove portion 81 is provided.
[0078]
　Since the inversion portion 80 is provided with the groove portions 81 and 82 in the region including the convex apex, the region including the convex apex is thinner than the other regions. Therefore, the strain energy accumulated by the deformation of the reversing portion 80 due to the external force exceeding the threshold value can be released at once from the groove portions 81 and 82, and the reversing portion 80 can be inverted to generate a click sound. Further, by adjusting the positions of the groove portions 81 and 82 in the thickness direction, it is possible to adjust the position where the reversing portion 80 reverses from the first state to the second state.
[0079]
　Further, since the groove portions 81 and 82 are formed in an arc shape in a side view, for example, as compared with the case where the groove portions 81 and 82 are formed in a V shape on two intersecting planes, the inverted portion 80 including the groove portions 81 and 82 is formed. The stress concentration at the apex can be relaxed even when the apex moves in the thickness direction.
[0080] [0080]
　As shown in FIG. 4, the distance d1 in the thickness direction between the crossing portion on the back surface side of the support portions 77H and 78H in the reversing portion 80 and the apex of the convex shape is 0.5 mm or more and 4.2 mm or less. Is preferable. The crossing portion on the back surface side with the support portions 77H and 78H in the reversing portion 80 is a position where the surface on the back surface side in the reversing portion 80 and the curved surfaces 75H and 76H of the supporting portions 77H and 78H intersect (in the side view, the reversing portion). It is a position where the straight line on the back surface side of 80 intersects with the curves of the curved surfaces 75H and 76H). When the distance d1 in the thickness direction is less than 0.5 mm, the energy that can be stored is small, and the reversing portion 80 may be inverted even with an appropriate load below the threshold value. In addition, since the energy released at the time of inversion is small, the click sound may not be sufficiently expressed. When the distance d1 in the thickness direction exceeds 4.2 mm, the reversing part 80 jumps and buckles due to the overbrushing pressure, making it difficult to reverse, or when the reversing part buckles and reverses, the reversing part 80 There is a possibility that 80 will break and lose its reversibility.
[0081]
　When the distance d1 in the thickness direction is within the above range, the bending energy generated in the toothbrush 1 is converged on the reversing portion 80, and the accumulated energy is released at once during the reversing (overbrushing) of the reversing portion 80. NS. As a result, a click sound is generated and the user can be made to sense that it is overbrushing.
[0082]
　The threshold value of the external force applied to the head portion 10 on the back surface side is, for example, an upper limit value of an appropriate brushing pressure.
[0083]
　As shown in FIG. 4, the angle θ at which the reversing portion 80 is tilted with respect to the plane parallel to the major axis direction and the width direction is preferably 5 degrees or more and 11 degrees or less. When the inclination angle θ is less than 5 degrees, the reversing portion 80 does not jump and buckle and does not generate a click sound, so that it may be difficult to detect the overbrushing state. When the inclination angle θ exceeds 11 degrees, the reversing portion 80 jumps and buckles due to the overbrushing pressure, making it difficult to generate a click sound, or jumping and buckling and flipping. At that time, the reversing portion 80 may be broken and the reversibility may be lost.
[0084]
　The thickness of the reversing portion 80 is preferably 1 mm or more and 2 mm or less, and more preferably 1.2 mm or more and 1.8 mm or less, excluding the groove portions 81 and 82. When the thickness of the reversing portion 80 is less than 1 mm, when an external force that causes overbrushing is applied, it is difficult to store energy of the deformed portion, so that it is difficult to generate a click sound and it is detected that the overbrushing state is present. Can be difficult. If the thickness of the reversing portion 80 exceeds 2 mm, deformation due to an external force is unlikely to occur and the bending energy cannot be released. Therefore, it becomes difficult for the reversing portion 80 to jump and buckle due to the overbrushing pressure and to generate a click sound. Alternatively, there is a possibility that the reversing portion 80 may be broken and the reversibility may be lost when the reversing is performed by jumping and buckling.
[0085]
　The minimum thickness of the inverted portion 80 in the region where the grooves 81 and 82 are formed is preferably 0.1 mm or more and 1.0 mm or less, and more preferably 0.3 mm or more and 0.8 mm or less. .. When the minimum thickness of the reversing part 80 is less than 0.1 mm, when an external force that causes overbrushing is applied, the reversing part 80 is gently deformed and it is difficult to store energy, so that it is difficult to generate a click sound. There is. If the minimum thickness of the reversing portion 80 exceeds 1.0 mm, it is difficult for deformation due to an external force to occur and the bending energy cannot be released, so that a clicking sound is difficult to occur.
[0086]
　Assuming that the maximum thickness of the reversing portion 80 is T (mm) and the maximum thickness of the sound generating portion 70 (elastic deformation portion 90) is t (mm), the value expressed in T / t is specified. When an excessive brushing load is applied, it becomes possible to control the ease of reversing of the reversing portion 80 and the timing (threshold value) thereof. The value represented by T / t is preferably 0.05 or more and 0.35 or less, and more preferably 0.10 or more and 0.35 or less. When the value represented by T / t is less than 0.05, the reversing part 80 also deforms in a manner that follows the bending of the sound generating part 70 (elastic deformation part 90), but the click sound is produced without jumping and buckling. Since it does not occur, it may be difficult to detect that it is in an overbrushing state. When the value represented by T / t exceeds 0.35, the reversing part 80 jumps and buckles due to the overbrushing pressure, making it difficult to flip and generate a click sound, or jumping and buckling. When inverted, it may break and the inverted portion 80 may lose its reversibility.
[0087]
　That is, by setting T / t within the above range, the bending strength of the reversing portion 80 becomes flexible at a constant ratio with respect to the elastic deforming portion 90, and the bending strength of the elastic deforming portion 90 that bears the handle skeleton is delayed. It becomes possible to operate the reversing portion 80 slightly. This makes it possible to control the ease of reversing of the reversing unit 80 and the timing (threshold value) that triggers the reversing of the reversing unit 80 even when an excessive brushing load is applied.
[0088]
　The maximum thickness t of the elastically deformed portion 90 is preferably 6 mm or more and 12 mm or less, and more preferably 8 mm or more and 10 mm or less. When the maximum thickness t of the elastically deformed portion 90 is less than 6 mm, the rigidity of the elastically deformed portion 90 is small, and although the inverted portion 80 is deformed, it may not jump and buckle and may not generate a click sound. In addition, when the maximum thickness t of the elastically deformed portion 90 is less than 6 mm, the energy that can be stored is small, and the reversing portion 80 may be inverted even with an appropriate load below the threshold value. If the maximum thickness t of the elastically deformed portion 90 exceeds 12 mm, the rigidity of the elastically deformed portion 90 may be too large to accumulate bending energy in the reversing portion 80.
[0089]
　As shown in FIG. 3, assuming that the maximum width of the reversing unit 80 is L (mm) and the maximum width of the sound generating unit 70 is W (mm), by specifying a value represented by L / W, for example. When an excessive brushing load is applied, it becomes possible to control the ease of reversing of the reversing unit 80 and the timing (threshold value) thereof. The values ​​represented by L / W are preferably 0.05 or more and 0.35 or less, and more preferably 0.10 or more and 0.35 or less. When the value represented by L / W is less than 0.05, the reversing part 80 also deforms in a manner that follows the bending of the sound generating part 70 (elastic deformation part 90), but it does not easily jump and buckle, and a click sound is produced. Since it is difficult to develop, it may be difficult to detect the overbrushing state. When the value represented by L / W exceeds 0.35, the inverted portion 80 is less likely to be deformed and inverted due to the bending of the handle body 2 that occurs in the range of normal brushing. Therefore, it becomes difficult for the reversing part 80 to jump and buckle due to the overbrushing pressure to generate a click sound, or when the reversing part 80 jumps and buckles and flips, it breaks and the reversibility of the reversing part 80 becomes high. It may disappear. By setting the value represented by L / W within the above range, the reversing portion 80 can be operated with a slight delay against the bending of the elastically deformed portion 90 that bears the handle skeleton. Therefore, even when an excessive brushing load is applied, it is possible to control the ease of reversing of the reversing unit 80 and the timing (threshold value) that triggers the reversing of the reversing unit 80.
[0090]
　The maximum width L of the reversing portion 80 is preferably 15 mm or less. When the maximum width L of the reversing portion 80 exceeds 15 mm, it is difficult for deformation due to an external force to occur and the bending energy cannot be released, so that a clicking sound is difficult to occur.
[0091]
　The length of the reversing portion 80 in the major axis direction is preferably 15 mm or more and 30 mm or less, more preferably 15 mm or more and 25 mm or less, and further preferably 15 mm or more and 20 mm or less. The position of the tip side end portion of the reversing portion 80 is the position of the tip end side end portion of the through hole 73. The position of the rear end side end portion of the reversing portion 80 is the position of the rear end side end portion of the through hole 73. When the length of the reversing part 80 in the long axis direction is less than 15 mm, the reversing part 80 jumps and buckles under normal brushing pressure, making it difficult to flip and generate a click sound, and also jumping and buckling. It may not be possible to produce the deformation required to develop the click sound. When the length of the reversing part 80 in the long axis direction exceeds 30 mm, the displacement required for jumping and buckling becomes very large, so that the usability is greatly reduced and the deformation behavior of the reversing part 80 is elastically deformed. The behavior is the same as that of the part 90, and it does not jump and buckle.
[0092]
　The reversing portion 80 is located between the outer contour of the flocked surface side 11 and the outer contour of the back surface side of the elastically deformed portion 90 in the side view. More specifically, the position of the reversing portion 80 in the thickness direction is such that the reversing portion 80 does not protrude from the thickness of the elastically deformed portion 90 in the side view so as not to form the outermost outer shell of the toothbrush. For example, it is possible to prevent the reversing portion from coming into contact with the user during use. Specifically, it is preferable that the elastically deformed portion 90 is on the back side rather than the position where the thickness is halved. When the position in the thickness direction of the reversing part 80 is on the back side of the position where the thickness of the sound generating part 70 is halved, when the reversing part 80 is reversed and the second state is reached, the reversing part 80 It is possible to reduce the possibility that the apex protrudes from the front surface of the elastically deformed portion 90 and comes into contact with the user's finger. Further, since the reversing portion 80 is arranged on the back surface side from the position where the thickness of the elastically deformed portion 90 is halved, the back surface side is compressed more than the front side when the reversing portion 80 is bent, for example. , The energy that triggers the inversion is likely to be accumulated, and the strain energy can be efficiently transferred to the inversion unit 80.
[0093]
　The flexural modulus of the hard resin constituting the reversing portion 80 is preferably 1500 MPa or more and 3500 MPa or less, and more preferably 2000 MPa or more and 3500 MPa or less. When the flexural modulus of the hard resin is less than 1500 MPa, the reversing portion 80 may be deformed but jump and buckle to not generate a click sound, and it may be difficult to detect the overbrushing state. When the flexural modulus of the hard resin exceeds 3500 MPa, the reversible portion 80 jumps and buckles due to the overbrushing pressure, making it difficult to generate a click sound, or when the reversible buckles and flips. There is a possibility that the reversible portion 80 will be broken and the reversibility of the reversing portion 80 will be lost. Further, by using a material having a specified flexural modulus, vibrations due to jumping and buckling are intensively generated in a short time to become sharp and loud, and a sufficient click sound is generated. As a result, the user can easily detect that it is overbrushing.
[0094]
　The moving distance of the convex apex in the thickness direction when the inverted portion 80 jumps and buckles is preferably 0.2 mm or more and 5.0 mm or less. If the moving distance of the apex in the thickness direction is less than 0.2 mm, the vibration at the time of jumping and buckling becomes small, and the click sound may not be sufficiently expressed. When the moving distance of the apex in the thickness direction exceeds 5.0 mm, the reversible portion 80 jumps and buckles due to the overbrushing pressure, making it difficult to flip and generate a click sound, or jumping and buckling. When it is inverted, it may break and the inverted portion 80 may lose its reversibility. If the moving distance of the reversing portion 80 is within the above range when the jumping buckling occurs, the vibration generated by the jumping buckling occurs intensively in a short time and becomes sharp (sharp, large). As a result, a click sound is generated, and the user can easily detect that it is overbrushing.
[0095]
　Further, the range in the thickness direction in which the reversing portion 80 is inverted is 1% or more of the maximum thickness t of the elastically deformed portion 90 centering on the line segment connecting the center points in the thickness direction of the supporting portions 77H and 78H. , 30% or less, more preferably 3% or more, and 15% or less. When the range in which the inversion portion 80 is inverted is less than 1% of the maximum thickness t, the vibration at the time of jumping and buckling becomes small, and the click sound may not be sufficiently expressed and it may be difficult to hear. When the range in which the inversion portion 80 is inverted exceeds 30% of the maximum thickness t, the inversion portion 80 jumps and buckles due to the overbrushing pressure, making it difficult to invert and generate a click sound, or jumping. When it is buckled and inverted, it may break and the inverted portion 80 may lose its reversibility.
[0096]
　The thickness of the hard portion 90H in the elastically deformed portion 90 is preferably 1.0 mm or more and 2.0 mm or less, and the width is preferably larger than the thickness. If the thickness of the hard portion 90H is less than 1.0 mm, the energy that can be stored is small, and the reversing portion 80 may be inverted even with an appropriate load below the threshold value. In addition, since the energy released at the time of inversion is small, the click sound may not be sufficiently expressed. When the thickness of the hard portion 90H is 2.0 mm or less, the hard portion 90H is in a plane stress state, so that the hard portion 90H is less likely to generate internal stress. As a result, even if it is deformed, it is less likely to break, and by sufficiently accumulating the energy required for the inversion of the inversion portion 80, it becomes possible to effectively express the click sound.
[0097]
　Further, in the toothbrush 1 of the present embodiment, since the reversing portion 80 and the elastic deforming portion 90 are arranged in the width direction, the sound generating portion 70 is more easily deformed to the front side and the back side, and the long axis direction and the elastic deformation part 90 are arranged. It is possible to create a plane stress state in which there is almost no deformation in the width direction. That is, in the toothbrush 1 of the present embodiment, the direction in which the reversing portion 80 and the elastic deforming portion 90 are deformed is the thickness direction separated from each other in the width direction, and the toothbrush 1 does not exist on the same plane. In other words, the path in which the elastically deformed portion 90 is deformed by the external force in the thickness direction and the path in which the reversing portion 80 is deformed by the external force in the thickness direction are provided in a non-interfering manner. Therefore, in the toothbrush 1 of the present embodiment, the elastic deforming portion 90 and the reversing portion 80 are less likely to be constrained by each other and can be deformed, so that the energy required for reversing the reversing portion 80 can be more sufficiently stored. , Stress is intensively generated in the reversing portion 80 (particularly, the groove portions 81 and 82), and a sharp jumping buckling can be generated to generate a click sound.
[0098]
　Further, in the toothbrush 1 of the embodiment, since the toothbrush 1 is suppressed from being shaken in the width direction, the bending in the thickness direction due to brushing can be transmitted to the reversing portion 80 without loss. Further, by arranging the inversion portion 80 and the elastic deformation portion 90 in the width direction, the bending of the elastic deformation portion 90 and the inversion of the inversion portion 80 can be made independent and the timing can be shifted. If the elastically deformed portion 90 and the inverted portion 80 are arranged in the thickness direction, the roles of the elastically deformed portion 90 and the inverted portion 80 may be hindered from each other.
[0099]
　As described above, in the toothbrush 1 of the present embodiment, the elastically deformed portion 90 that elastically deforms at least until the external force that the inverted portion 80 jumps and buckles and reverses, and the external force to the back side that exceeds the threshold value. Since the reversing portion 80 that jumps, buckles, and reverses is arranged with a gap in the width direction, the head portion 10 is reversed when an external force exceeding a predetermined threshold value is applied to the back surface side. Since the click sound can be generated by the vibration when the portion 80 jumps, buckles, and reverses, the user who grips the grip portion 30 has an overload of the external force applied to the head portion 10 on the back surface side exceeding the threshold value. It can detect that it is in a brushing state.
[0100]
[Examples]
　Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples, and may be appropriately modified and carried out without departing from the gist thereof. can.
[0101]
(Examples 1 to 9, Comparative Example 1)
According to the specifications shown in [Table 1], the presence / absence of a sound generating portion, the A characteristic sound pressure level, the click frequency, the number of elastically deformed portions, the number of inverted portions, and the elastically deformed portions. Toothbrushes having different interference relations between the elastically deformed portion and the inverted portion, the positional relationship between the elastically deformed portion and the inverted portion (arrangement direction), and the bending elasticity of the elastically deformed portion and the hard portion of the inverted portion are different from the samples of Examples 1 to 9 and Comparative Example 1. bottom. The thickness of the elastically deformed portion in each sample was 9.8 mm. The thickness of the hard portion of the elastically deformed portion in each sample was 2.0 mm.
[0102]
　In Examples 1 to 3, a toothbrush having a sound generating portion described in the above embodiment was used as a sample. In Example 4, a toothbrush in which elastically deformed portions were arranged via gaps on both sides in the thickness direction sandwiching the inverted portion was used as a sample. In Example 5, a toothbrush in which an inversion portion and one elastically deformed portion were arranged via a gap on one side and the other side in the thickness direction was used as a sample. In the sixth embodiment, a so-called butterfly hinge is provided, which is not provided with an elastic deformation portion, extends in the long axis direction, and has a bowl-shaped arc shape in which the cross-sectional shape cut in a plane including the width direction and the thickness direction is convex toward the back side. A toothbrush having a mold reversal part was used as a sample. In the seventh embodiment, the elastically deformed portion has the same configuration as that of the first embodiment, and instead of the reversing portion, the base end is located on the rear end side of the sound generating portion and extends toward the tip side, and the base end is the sound. The second engaging part located on the tip side of the generating part and extending to the rear end side is arranged with a gap in the thickness direction and separated from the elastically deformed part, and the external force in the thickness direction is the threshold value. The sample was a toothbrush whose positional relationship in the thickness direction was reversed after engaging with each other when the amount exceeded. In Example 8, a toothbrush provided with no gap between the elastically deformed portion and the inverted portion was used as a sample with respect to the sample of Example 1. In Example 9, a toothbrush in which the hard portion of the elastically deformed portion was not covered with the soft portion was used as a sample with respect to the sample of Example 1. In Comparative Example 1, a toothbrush (Clinica Advantage Habrush manufactured by Lion Corporation) having no sound generating portion (reversing portion and elastic deformation portion) was used as a sample. The flocked part has the same specifications as the Clinica Advantage toothbrush.
[0103]
[Measuring method of click sound] For
　each sample, the grip portion 30 side was fixed from the boundary between the sound generating portion 70 and the grip portion 30 so that the flocked surface of the head portion was horizontal. The click sound when the center of the head portion 10 was loaded vertically downward and the inverted portion was inverted at a constant speed (100 mm / min) was measured. The measurement was performed using a microphone placed at a distance of 15 cm (15 cm in the front side direction from the deformed part) from the sample, assuming the distance from the center of the sound generating part to the user's ear (measurement 3 times). (Adopt the average value of). The measurement was performed in a quiet room where the measurement sound was not affected.
[0104]
[Evaluation method of click sound]
(Investigation method) A
questionnaire was conducted after using a total of 10 toothbrush samples of Examples 1 to 9 and one toothbrush sample of Comparative Example 1 for one week. The survey was conducted by eight toothbrush expert panelists who can appropriately control the brushing load.
　Regarding "easiness to hear click sound", "very good sound" is set to "4 points", "good sound" is set to "3 points", "hearing" is set to "2 points", and "not heard" is set. The score was set to "1 point", and the average score obtained for each sample was used (an index of "easy to understand force adjustment"). The average value of the scores was rounded off to the first decimal place.
　Regarding the ease with which the click sound is generated under the overbrushing load, "4 points" is set to "exactly interlocks with the overbrushing load and the sound is produced", and "accurately interlocks with the overbrushing load and the sound is produced". "Appears" is set to "3 points", "Sound is generated when overbrushing load is linked" is set to "2 points", and "Sound is not linked to overbrushing load" is set to "1 point". The average score obtained for each sample was used (an index of "easy to understand force adjustment"). The average value of the scores was rounded off to the first decimal place. In this survey, the threshold value for the overbrushing load was set to 200 g.
　Regarding the evaluation results, those with an average score of 2.0 points or more were regarded as acceptable (OK), and those with an average score of less than 2.0 points were regarded as rejected (NG).
[0105]
[table 1]

[0106]
　As shown in [Table 1], the samples of Examples 1 to 9 having the sound generating part have the A characteristic sound pressure level of 30 dB or more, the frequency of 100 Hz or more and 10,000 Hz or less, and "hearing a click sound". Both "ease" and "ease of displaying click sound under overbrushing load" were acceptable (OK). On the other hand, the sample of Comparative Example 1 having no sound generating part did not develop a click sound and was rejected (NG).
[0107]
　Further, for the samples of Examples 1 to 5 and 7 to 9 in which the flexural modulus of the hard resin of the elastically deformed portion and the inverted portion is 1500 MPa or more, "easiness to hear the click sound" and "click sound due to overbrushing load" are also obtained. It was confirmed that both of "ease of expression" were passed (OK).
[0108]
　Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above examples. The various shapes and combinations of the constituent members shown in the above-mentioned example are examples, and can be variously changed based on design requirements and the like within a range not deviating from the gist of the present invention.
[0109]
　For example, in the above embodiment, the configuration in which the sound generating portion 70 is provided between the neck portion 20 and the grip portion 30 is exemplified, but the configuration is not limited to this configuration. The sound generation unit 70 may have a configuration provided in the neck portion 20 or a configuration provided in the grip portion 30.
[0110]
　Further, in the above embodiment, the configuration in which one inversion unit 80 is provided in the sound generation unit 70 is exemplified, but the configuration is not limited to this configuration, and a configuration in which a plurality of inversion units 80 are provided may be used.
　For example, when two reversing portions 80 are provided, one is formed to have a thickness and inclination angle θ that are inverted at the upper limit of the appropriate brushing load, and the other is inverted at the lower limit of the appropriate brushing load. By forming the structure at an angle θ or the like, it is possible to easily specify both the upper limit value and the lower limit value of the brushing load.
[0111]
　Further, in the above embodiment, the configuration in which the reversing portion 80 is inverted in the thickness direction is exemplified, but the configuration is not limited to this configuration, and for example, it is orthogonal to the width direction and the major axis direction and is orthogonal to the width direction and the thickness direction. It may be configured to be inverted in the diagonal direction where it intersects. By adopting a configuration in which the reversing portion 80 is inverted in the diagonal direction, it becomes possible to detect overbrushing when brushing by the rolling method.
Industrial applicability
[0112]
　The present invention is applicable to toothbrushes.
Code description
[0113]
　1 ... toothbrush, 2 ... handle body, 10 ... head part, 11 ... flocked surface, 20 ... neck part, 30 ... grip part, 70 ... sound generating part, 77H, 78H ... support part, 80 ... reversing part, 81, 82 ... Groove, E, 31E, 32E ... Soft part, H ... Hard part, S ... Gap
The scope of the claims
[Claim 1]
　It has a head portion provided on the tip side in the long axis direction and having a flocked surface, a grip portion arranged on the rear end side of the head portion, and a neck portion arranged between the flocked surface and the grip portion. The
　tooth brush is characterized by having a sound generating portion on the rear end side of the flocked surface, which generates a clicking sound due to deformation when an external force in the first direction orthogonal to the flocked surface exceeds a threshold value.
[Claim 2]
　The toothbrush according to claim 1, 　wherein the sound generated from the sound generating unit has an
　A characteristic sound pressure level of 30 dB or more and a
　frequency of 100 Hz or more and 10,000 Hz or less
.
[Claim 3]
　The sound generating portion
　jumps and buckles and reverses due to the displacement of the head portion to the back surface side opposite to the flocked surface in the first direction due to the external force exceeding the threshold value.
　The toothbrush according to claim 1 or 2 , further comprising an inversion portion that generates the click sound when the toothbrush is used.
[Claim 4]
　The sound generating section connects
　the first region on the tip side of the sound generating section and the second region on the rear end side of the sound generating section, and at least the sound generating section generates the click sound.
　The toothbrush according to claim 3, further comprising an elastically deformed portion that elastically deforms up to the external force .
[Claim 5]

　The toothbrush according to claim 3, 　wherein the elastically deformed portion and the inverted portion are arranged with a gap in a second direction orthogonal to the first direction and the major axis direction, respectively .
[Claim 6]
　The elastically deformed portion has a hard portion formed of a hard resin and a soft portion formed of a soft resin and covering the hard portion, and the
　inverted portion is formed of a hard resin having a flexural modulus of 1500 MPa or more. It is,
　toothbrush according to claim 4 or 5.
[Claim 7]
　The thickness of the elastically deformed portion in the first direction is 6 mm or more and 12 mm or less, and the
　sound generating portion is formed of the hard resin on both ends in the major axis direction, and the elastically deformed portion and the inverted portion are formed. The
　inverted portion has a support portion that supports both ends of the portion in the major axis direction, and the inverted portion is an elastically deformed portion centered on a line segment connecting the center points of the thickness in the first direction of the support portion. The
　toothbrush according to claim 6 , which is inverted in the range of 1% or more and 30% or less of the thickness in the first direction .
[Claim 8]
　The inverted portion has a convex shape on the back surface side when the external force in the first direction is equal to or less than a threshold value, and
　the intersection of the back surface side with the support portion and the apex of the convex shape are the first.
　The toothbrush according to claim 7 , wherein the distance in one direction is 0.5 mm or more and 4.2 mm or less .
[Claim 9]

　The toothbrush according to claim 8, 　wherein the inverted portion has a groove portion extending in the second direction on at least one of the flocked surface side and the back surface side in a region including the apex of the convex shape .
[Claim 10]

　The toothbrush according to claim 9, 　wherein the minimum thickness of the inverted portion in the region provided with the groove portion in the first direction is 0.1 mm or more and 1.0 mm or less .
[Claim 11]

　The toothbrush according to any one of claims 6 to 10 　, wherein the thickness of the hard portion in the first direction is 1.0 mm or more and 2.0 mm or less .