The present invention relates to a toothbrush.
　This application claims priority based on Japanese Patent Application No. 2018-246145 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. The toothbrush disclosed in Patent Document 1 is arranged between the head portion and the grip portion, and has a two-beam structure of a rear beam to which compressive stress is applied and a facial beam to which tensile stress is applied during normal use. There is.
[0006]
　In this toothbrush, when the user grips the grip, the rear beam to which a compressive force exceeding the determined force is applied is elastically buckled and convex downward from an upwardly convex arc. Invert to a circular arc. As described above, the toothbrush disclosed in Patent Document 1 can make the user recognize that the appropriate brushing pressure has been exceeded by reversing the rear beam.
Prior art literature
Patent documents
[0007]
Patent Document 1: Japanese Patent Application Laid-Open No. 6-504937
Outline of the invention
Problems to be solved by the invention
[0008]
　However, in the toothbrush disclosed in Patent Document 1 described above, when an excessive brushing load is applied, the rear beam is deformed in a direction approaching the facial beam, so that the amount of deformation of the rear beam is limited and general purpose. The sex is not enough.
[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 recognizing an appropriate brushing pressure with high versatility.
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. It has a neck portion arranged between the two, and a sensing portion for sensing that the external force in the first direction orthogonal to the flocked surface exceeds the threshold value is provided on the rear end side of the flocked surface. The sensing unit connects the first region on the tip side of the sensing unit and the second region on the rear end side of the sensing unit, and the external force exceeding the threshold value causes the first region. With the displacement of the head portion to the back side opposite to the flocked surface in one direction, the reversing portion that jumps, buckles and reverses, and the reversing portion are arranged with a gap. The region is connected to the second region, and at least the inverted portion is provided with an elastically deformed portion that elastically deforms up to the external force of jumping, buckling, and reversing, and the inverted portion is provided in the long axis direction and the first direction. Provided is a toothbrush characterized in that it is located between the outer contour on the flocked surface side and the outer contour on the back surface side in the elastically deformed portion in a side view viewed in a direction orthogonal to the above.
[0011]
　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.
[0012]
　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.
[0013]
　Further, in the toothbrush according to one aspect of the present invention, the inverted portion has a convex shape toward the back surface when the external force in the first direction is equal to or less than the threshold value, and the external force in the first direction is a threshold. It is characterized in that when the value is exceeded, it is inverted into a convex shape toward the flocked surface side.
[0014]
　Further, in the toothbrush according to one aspect of the present invention, when the external force in the first direction is equal to or less than the threshold value, the inverted portion is directed from the apex of the convex shape toward the end in the long axis direction. The angle at which the inverted portion is inclined toward the hair-planted surface side and the inverted portion is inclined with respect to a plane parallel to the first direction and the major axis direction, respectively, is 5 degrees or more and 11 degrees or less. do.
[0015]
　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.
[0016]
　Further, in the toothbrush according to one aspect of the present invention, when the inverted portion jumps and buckles and inverts, the moving distance of the convex apex in the first direction is 0.2 mm or more and 5.0 mm. It is characterized by the following.
[0017]
　Further, in the toothbrush according to one aspect of the present invention, the inverted portion is provided in the center of the second direction, and the elastically deformed portion is provided on both sides of the second direction with the inverted portion interposed therebetween. It is characterized by being.
[0018]
　Further, in the toothbrush according to one aspect of the present invention, where T is the maximum thickness of the inverted portion in the first direction and t is the maximum thickness of the elastically deformed portion in the first direction, T / t. The value represented by is characterized by being 0.05 or more and 0.35 or less.
[0019]
　Further, in the toothbrush according to one aspect of the present invention, where L is the maximum width of the inverted portion in the second direction and W is the maximum width of the elastically deformed portion in the second direction, it is represented by L / W. The values ​​to be set are 0.05 or more and 0.35 or less.
[0020]
　Further, in the toothbrush according to one aspect of the present invention, the inverted portion is formed of a hard resin, and a part of the elastically deformed portion is formed of a resin having a hardness different from that of the hard resin. It is a feature.
[0021]
　Further, in the toothbrush according to one aspect of the present invention, the flexural modulus of the hard resin is 1500 MPa or more and 3500 MPa or less.
[0022]
　Further, in the toothbrush according to one aspect of the present invention, a part of the elastically deformed portion is made of a soft resin.
[0023]
　Further, in the toothbrush according to one aspect of the present invention, the gap is characterized by being a through hole extending in the first direction.
The invention's effect
[0024]
　INDUSTRIAL APPLICABILITY The present invention can provide a toothbrush capable of recognizing an appropriate brushing pressure with high versatility.
A brief description of the drawing
[0025]
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 sensing portion 70 cut along a plane parallel to the thickness direction and the width direction.
FIG. 4 is a cross-sectional view of the sensing 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 periphery of the sensing portion 70 in the rigid portion 70H.
FIG. 6 is a partial side view of the periphery of the sensing portion 70 in the rigid portion 70H.
FIG. 7 is a cross-sectional view of the sensing portion 70 cut along a plane parallel to the thickness direction and the major axis direction to explain that the inverted portion has been inverted.
Embodiment for carrying out the invention
[0026]
　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.
[0027]
　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).
[0028]
　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 sensing portion 70 extending to the rear end side of the neck portion 20, and the rear end side of the sensing portion 70. It includes an extended grip portion 30 (hereinafter, the head portion 10, the neck portion 20, the grip portion 30, and the sensing portion 70 are collectively referred to as a handle body 2).
[0029]
　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 sensing portion 70. The soft portion E constitutes a part of each of the grip portion 30 and the sensing portion 70 (details will be described later).
[0030]
[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.
[0031]
　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.
[0032]
　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.
[0033]
　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.
[0034]
　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.
[0035]
　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.
[0036]
　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.
[0037]
　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.
[0038]
　The cross-sectional shape of the hair is not particularly limited, and may be a circular shape such as a perfect circle or an ellipse, 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.
[0039]
　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.
[0040]
[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.
[0041]
　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.
[0042]
　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.
[0043]
　The boundary between the neck portion 20 and the sensing 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 sensing portion 70 is one 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 width direction in the front view shown in FIG. I am doing it. Further, the boundary between the neck portion 20 and the sensing 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. There is.
[0044]
[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 toward the rear end side from the boundary with the sensing portion 70, and then extends at 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 sensing portion 70 toward the rear end side, and then extends at a substantially constant length.
[0045]
　The boundary between the sensing portion 70 and the grip portion 30 in the present embodiment is the position of the tip of the grip portion side 30 on which the elastically deformed portion 90 described later is provided. Here, the width is reduced from the sensing 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 coincides with the changed position in the long axis direction. ing. More specifically, the boundary between the sensing portion 70 and the grip portion 30 is one with the position in the major 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. I am doing it. Further, the boundary between the sensing 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. ..
[0046]
　The length in the width direction of the grip portion 30 gradually narrows from the boundary with the sensing portion 70 toward the rear end side, and then becomes a substantially constant length. The positions in the long axis direction are the same so that the length gradually narrows from the boundary with the sensing unit 70 toward the rear end side and then becomes a substantially constant length.
[0047]
　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 from the boundary with the sensing portion 70 toward the rear end side 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.
[0048]
　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 sensing portion 70 toward the rear end side in the front view, and then extends at a substantially constant length.
[0049]
　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.
[0050]
　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 sensing 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.
[0051]
　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 sensing portion 70 toward the rear end side in the rear view, and then extends at a substantially constant length.
[0052]
　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.
[0053]
　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.
[0054]
[Sensing unit 70] The
　sensing unit 70 senses that the external force in the first direction orthogonal to the flocked surface 11 has exceeded the threshold value. As shown in FIG. 1, the sensing portion 70 has a reversing portion 80 and an elastic deformation portion 90 that connect a neck portion 20 on the distal end side of the sensing portion 70 and a grip portion 30 on the rear end side of the sensing portion 70. doing.
[0055]
　FIG. 3 is a cross-sectional view of the sensing portion 70 cut in a plane parallel to the thickness direction and the width direction. FIG. 4 is a cross-sectional view of the sensing 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.
[0056]
　By providing the gap S, the reversing portion 80 can be inverted (easily inverted) without interfering with the surrounding structure. Further, since the deformation of the reversing portion 80 does not follow the deformation of the elastic deforming portion (because it does not interfere), the functional roles (described later) of the reversing portion 80 and the elastic deforming portion 90 can be made independent. As a result, for example, the degree of freedom in design for obtaining the following effects can be increased. For example, vibration / sound when the reversing unit 80, which will be described later, is reversed can be clearly generated. Further, for example, the repulsive force up to the threshold value can be increased in proportion to the displacement amount, and the proportional relationship can be maintained even in the vicinity of the threshold value (increased repulsive force). The degree does not become loose). As a result, in the region up to the displacement amount reaching the upper limit pressure, the pressure assumed by the user is directly reflected in the repulsive force, so that the brushing load can be appropriately controlled. If the degree of increase in the repulsive force gradually decreases near the threshold value, the user may unintentionally continue brushing at a pressure near the upper limit. Further, if the gap S is communicated with both sides of the reversing portion 80 in the thickness direction, the effect is further improved. By widening the gap S in the thickness direction, the vector of the load applied to the brush portion (brush) during brushing, the direction in which the gap opens, and the direction in which the reversing portion 80 and the elastically deforming portion 90 are deformed become parallel ( (See FIG. 7), it becomes easy to link the generation of vibration / sound due to inversion with the brushing load. Further, if the gap S is penetrated between the front side and the back side by the through hole K, for example, the movable region of the elastic deformation portion 90 which is responsible for the bending function of the toothbrush skeleton with respect to the load at the time of brushing can be further expanded. (The tensile behavior on the front surface and the compression behavior on the back surface due to bending are less likely to be hindered). When the through hole K does not exist between the elastically deformed portion 90 and the inverted portion 80, the movable region of the elastically deformed portion 90 becomes narrow. In this case, the inversion part 80 is not given an opportunity to invert in an appropriate load range, and the inversion unit 80 inverts before reaching an appropriate load range, or does not invert even in an appropriate load range. The state is assumed. On the other hand, by providing the through hole K between the elastically deformed portion 90 and the reversing portion 80, the “threshold value” at which the reversing portion 80, which will be described later, reverses can be controlled in a finer range. The gap S does not have to penetrate in the thickness direction, and may be formed, for example, by a closed cavity extending in the major axis direction inside the elastically deformed portion 90. Further, it may be formed by a recess (described later) that opens on the front side or the back side.
[0057]
　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. A reversing 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.
[0058]
　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.
[0059]
　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 on both the front end side and the rear end side of the elastic deformation portion 90, the anisotropy in the sensing portion 70 is increased, and for example, the pair of elastic deformation portions 90 moves during brushing. On the other hand, it becomes possible to bend without twisting in the thickness direction. 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 sensing portion 70 (the neck portion 20 and the elastically deformed portion 90) is enhanced. ..
[0060]
　FIG. 5 is a partial front view of the sensing portion 70 around the hard portion 70H. FIG. 6 is a partial side view of the sensing 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 neck portion 20 and the hard portion 30H of the grip portion 30 in the long axis direction.
[0061]
　As shown in FIG. 6, the front end side of the hard portion 70H 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 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.
[0062]
　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).
[0063]
　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.
[0064]
　In the hard portion 70H, since the hard portion 90H is arranged on both sides in the width direction with the reversing portion 80 as the center via the through holes 73, the reversing portion 80 is deformed even if a load is applied and the elastic deforming portion 90 is deformed. Can maintain the shape of. When the hard portion H constituting the toothbrush 1 over the entire length is bent, the reversing portion 80 of the sensing 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.
[0065]
　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.
[0066]
　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 made thin or thin, when an excessive load is applied, jumping buckling occurs and vibration is generated. 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.
[0067]
　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.
[0068]
　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.
[0069]
　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.
[0070]
　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 reversing portion 80 is formed in a convex shape on the front side where the center in the major axis direction is the apex.
[0071]
　That is, when the magnitude of the external force exceeds a predetermined threshold value, the elastically deformed portion 90 elastically deforms, so that the inverted portion 80 jumps from the first state while the bending strength in the sensing portion 70 is guaranteed. It shifts to buckle and reverses to 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.
[0072]
　The user who grips the grip portion 30 due to the vibration when the reversing portion 80 jumps, buckles, and flips, is in an overbrushing state in which the external force applied to the head portion 10 on the back surface side exceeds the threshold value. Can be sensed.
[0073]
　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, stress is uniformly generated in the entire reversing portion 80, and jumping buckling is less likely to occur. On the other hand, when the grooves 81 and 82 are provided in the reversing portion 80, stress is intensively generated in the grooves 81 and 82, and jumping buckling is likely to occur.
[0074]
　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 groove portions 81 and 82 exceeds 2 mm, the vibration of the reversing portion 80 at the time of reversing becomes small, and it may be difficult to detect that the reversing portion 80 is in the overbrushing state.
[0075]
　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.
[0076]
　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 instantly released from the groove portions 81 and 82 as the starting point, and the reversing portion 80 can be inverted. 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.
[0077]
　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.
[0078]
　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.
[0079]
　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, and 7 degrees or more and 11 degrees. It is more preferably less than or equal to the degree. When the inclination angle θ is less than 5 degrees, the reversing portion 80 jumps and deforms without buckling, which may make it difficult to detect the overbrushing state. When the inclination angle θ exceeds 11 degrees, the reversing section 80 jumps and buckles due to the overbrushing pressure, making it difficult to flip, or when the flipping section buckles and flips, the flipping section 80 jumps and buckles. It may break and lose its reversibility.
[0080] [0080]
　The thickness of the reversing portion 80 is preferably 1 mm or more and 2 mm or less, excluding the groove portions 81 and 82. If the thickness of the reversing portion 80 is less than 1 mm, although it is deformed, it does not jump and buckle, and it may be difficult to detect that it is in an overbrushing state. If the thickness of the reversing portion 80 exceeds 2 mm, the reversing portion 80 jumps and buckles due to the overbrushing pressure, making it difficult to reverse, or the reversing portion 80 breaks when the reversing portion 80 jumps and buckles and reverses. And there is a possibility that the reversibility will be lost.
[0081]
　Assuming that the maximum thickness of the reversing unit 80 is T (mm) and the maximum thickness of the sensing unit 70 is t (mm), an excessive brushing load is applied by specifying a value expressed in T / t. At this time, it becomes possible to control the ease of inversion of the inversion unit 80 and its timing (threshold value). 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 form that follows the bending of the sensing part 70 (elastic deformation part 90), but it does not jump and buckle, so that it is overbrushed. It can be difficult to detect the condition. If the value represented by T / t exceeds 0.35, the reversible portion 80 jumps and buckles due to the overbrushing pressure, making it difficult to flip, or jumps and buckles and breaks when flipped. Therefore, there is a possibility that the reversibility of the inversion unit 80 will be lost.
[0082]
　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.
[0083]
　As shown in FIG. 3, assuming that the maximum width of the reversing unit 80 is L (mm) and the maximum width of the sensing 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 form that follows the bending of the sensing part 70 (elastic deformation part 90), but it does not easily jump and buckle, and is in an overbrushing state. It can be difficult to perceive that. 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, there is a possibility that the reversing portion 80 jumps and buckles due to the overbrushing pressure, making it difficult to reverse, or when the reversing portion 80 jumps and buckles and reverses, it breaks and the reversibility of the reversing portion 80 is lost. .. That is, by setting L / W 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. 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.
[0084]
　The length of the reversing portion 80 in the major axis direction is 15 mm or more and 30 mm or less. It is preferably 15 mm or more and 25 mm or less, more 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 major axis direction is less than 15 mm, the reversing part 80 jumps and buckles under normal brushing pressure, making it difficult to reverse and jumping buckling, which is necessary. It may not be possible to cause deformation. 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. There is a possibility that the behavior will be the same as that of the part 90.
[0085]
　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 portion 80 is on the back side of the position where the thickness of the sensing portion 70 is halved, the apex of the reversing portion 80 is in the second state when the reversing portion 80 is inverted. Can reduce the possibility that the elastically deformed portion 90 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.
[0086]
　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 deforms but does not jump and buckle, and it may be difficult to detect that it is in an overbrushed 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 reverse, or when the reversible buckles and reverses, it breaks and reverses. There is a possibility that the reversibility of the part 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 and become sharp (sharp, large). As a result, the user can easily detect that it is overbrushing.
[0087]
　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 it may be difficult to detect the overbrushing state. 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, or when the flipping buckles and flips. There is a possibility that it will break and the reversibility of the reversing portion 80 will be lost. 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, the user can easily detect that it is overbrushing.
[0088]
　The thickness of the hard portion 90H in the elastically deformed portion 90 is preferably 2.0 mm or less, and the width is preferably larger than the thickness. 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 it becomes possible to sufficiently store the energy required for the inversion of the inversion portion 80.
[0089]
　Further, in the toothbrush 1 of the present embodiment, since the reversing portion 80 and the elastic deforming portion 90 are arranged with a gap in the width direction, the sensing portion 70 is more easily deformed to the front side and the back side, and the length is long. It is possible to obtain a plane stress state in which there is almost no deformation in the axial direction and 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 sharp jump buckling is developed.
[0090]
　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.
[0091]
　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. The user who grips the grip portion 30 senses that the external force applied to the head portion 10 to the back surface side exceeds the threshold value due to the vibration when the portion 80 jumps, buckles, and reverses. can.
[0092]
[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.
[0093]
(Examples 1 to 9, Comparative Examples 1 to 4)
According to the specifications shown in [Table 1], toothbrushes having different flexural modulus and inclination angle θ of the reversing portion 80 are used as samples of Examples 1 to 9 and Comparative Examples 1 to 4. And said. For Comparative Example 1, a toothbrush (Clinica Advantage Habrush manufactured by Lion Corporation) having no sensing portion (reversing portion and elastic deformation portion) was used as a sample. As for Comparative Example 2, a toothbrush in which the elastically deformed portion and the inverted portion are arranged in the thickness direction with respect to the sample of Example 2 was used as a sample. For Comparative Example 3, a toothbrush having a sensing portion having only an inverted portion without an elastic deformation portion was used as a sample with respect to the sample of Example 2. For Comparative Example 4, a toothbrush having a sensing portion in which the elastically deformed portion and the inverted portion were joined to each other and there was no gap between the elastically deformed portion and the inverted portion was used as a sample with respect to the sample of Example 2.
[0094]
[Evaluation method]
(1) Vibration manifestation of inversion part
[Test method] A specialized panel (5 people) brushes using each sample, and whether or not vibration is felt when the inversion part is inverted 5 in actual use. It was evaluated by the grade of the grade, and the average value of the grade was evaluated as follows. The average value of the scores was rounded off to the first decimal place.
[Score] 5 points: Very feel, 4 points: Feel, 3 points: Slightly feel, 2 points: Not very feel, 1 point: Not feel at all
[Evaluation] ◎: 4.6-5 points, ○: 4. 1 to 4.5 points, Δ: 3.1 to 4.0 points, ×: 3.0 points or less
(2) Reversible inversion of the inversion part
[Test method] Specialized panel (5 people) prepares each sample. It was used for 1 week and the presence or absence of reversal after 1 week was evaluated.
[Evaluation] ○: With inversion, ×: Without inversion
( × if even one is not inverted) (3) Vibration manifestation at about 200 to 250 g
[Test method] For each sample, the flocked surface of the head part is horizontal. The grip portion 30 side was fixed from the boundary between the sensing portion 70 and the grip portion 30 so as to be. A test was conducted in which a load was applied to the flocked surface of the head portion on the back side in the thickness direction. A push-pull gauge (DS2-50N, manufactured by IMADA) was used to push the center of the front view of the flocked surface in the head portion, and the load when the inverted portion was inverted was measured.
　The measurement was performed three times and the average value was used as the measured value. For the average value, the first decimal place was rounded off.
[Evaluation] ◎: 200 to 250 g, ○: 251 to 300 g, Δ: 150 to 199 g, ×: 149 g or less, or 301 g or more,-: No vibration
　Regarding the evaluation results, ⊚, ○, and Δ were regarded as acceptable (OK), and × was regarded as rejected (NG).
　In the evaluation of the measured load, the vibration at the time of reversal is expressed in the range of, for example, 230 to 250 g, and the load when the user actually brushes with the toothbrush 1 is 200 g, which is the recommended value. Is a value.
[0095]
　As shown in [Table 1], in the samples of Examples 1 to 9 in which the flexural modulus is 1500 MPa or more and 3500 MPa or less and the inclination angle θ of the inversion portion is 5 degrees or more and 11 degrees or less, the inversion portion is shown. It was confirmed that the vibration accompanying the reversal, the reversible reversal of the reversing part, and the vibration with a load of about 200 to 250 g were sufficiently exhibited.
[0096]
　On the other hand, even if the flexural modulus is in the range of 1500 MPa or more and 3500 MPa or less, the sample of Comparative Example 1 having no sensing portion (reversing portion and elastically deforming portion) does not undergo reversing itself, and therefore, reversing of the reversing portion. No vibration and vibration at a load of about 200 to 250 g occurred. Further, in the range where the elastic modulus is 1500 MPa or more and 3500 MPa or less, and the inclination angle θ of the inversion portion is 5 degrees or more and 11 degrees or less, the value represented by T / t and the value represented by L / W are. , 0.05 or more and 0.35 or less, the sample of Comparative Example 2 in which the elastically deformed portion and the inverted portion are lined up in the thickness direction, and the sensing portion having no elastically deformed portion and only the inverted portion. In each of the samples of Comparative Example 3 having
[0097]
　Further, in the range where the elastic modulus is 1500 MPa or more and 3500 MPa or less, and the inclination angle θ of the inversion portion is 5 degrees or more and 11 degrees or less, the value represented by T / t and the value represented by L / W are. , 0.05 or more and 0.35 or less, but there is no gap between the elastically deformed portion and the inverted portion, and the sample of Comparative Example 4 having a sensing portion in which the elastically deformed portion and the inverted portion are joined. As for, although the vibration accompanying the reversal of the reversing part occurred, the vibration did not occur at a load of about 200 to 250 g.
[0098]
[table 1]

[0099]
　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.
[0100]
　For example, in the above embodiment, the configuration in which the sensing 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 sensing portion 70 may have a configuration provided in the neck portion 20 or a configuration provided in the grip portion 30.
[0101]
　Further, in the above embodiment, the configuration in which one inversion unit 80 is provided in the sensing 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.
[0102]
　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
[0103]
　The present invention is applicable to toothbrushes.
Description of the sign
[0104]
　1 ... toothbrush, 2 ... handle body, 10 ... head part, 11 ... flocked surface, 20 ... neck part, 30 ... grip part, 70 ... sensing part, 80 ... reversing part, 81, 82 ... groove part, E, 31E, 32E ... soft part, H ... hard part, K ​​... through hole, 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. and,
　on the rear end side of the flocked surface, sensing unit external force in the first direction to detect that the threshold is exceeded is provided perpendicular to the bristle face,
　the sensing unit,
　than the sensing unit The first region on the tip side and the second region on the rear end side of the sensing portion are connected, and the external force exceeding the threshold value causes the flocking surface to be opposite to the flocked surface in the first direction. With the displacement of the head portion to a certain back side, an inversion portion that jumps and buckles and inverts, and an inversion portion
　that is arranged with a gap from the inversion portion, and connects the first region and the second region, at least. The inverted portion includes an elastically deformed portion that elastically deforms up to the external force in which the inverted portion jumps, buckles, and inverts, and the
　inverted portion is the side view viewed in the major axis direction and the direction orthogonal to the first direction. A toothbrush characterized in that it is located between the outer contour on the flocked surface side and the outer contour on the back surface side in the elastically deformed portion.
[Claim 2]
　Claim 1 is characterized in that the path in which the elastically deformed portion is deformed by the external force in the first direction and the path in which the inverted portion is deformed by the external force in the first direction are provided in a non-interfering manner. Toothbrush described in.
[Claim 3]

　The toothbrush according to claim 2, 　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 4]

　The toothbrush according to claim 3, wherein the reversing portion is 　provided in the center of the second direction, and the elastically deforming portion is provided on both sides of the second direction with the reversing portion interposed therebetween.
[Claim 5]
　The inverted portion has a convex shape toward the back surface when the external force in the first direction is equal to or less than the threshold value, and has a convex shape toward the flocked surface side when the external force in the first direction exceeds the threshold value.
　The toothbrush according to any one of claims 1 to 4, which is inverted to .
[Claim 6]
　When the external force in the first direction is equal to or less than the threshold value, the inverted portion is inclined in a direction toward the flocked surface side from the apex of the convex shape toward the end portion in the long axis direction, and the inverted portion is
　inverted.
　The toothbrush according to claim 5, wherein the angle at which the portion is inclined with respect to a plane parallel to the first direction and the major axis direction is 5 degrees or more and 11 degrees or less .
[Claim 7]

　The toothbrush according to claim 5 or 6, 　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 8]

　Any one of claims 5 to 7, 　wherein the moving distance of the convex apex in the first direction is 0.2 mm or more and 5.0 mm or less when the inverted portion jumps, buckles, and inverts. The toothbrush described in the section.
[Claim 9]
　Assuming that the maximum thickness of the inverted portion in the first direction is T and the maximum thickness of the
　elastically deformed portion in the first direction is
　t, the values ​​represented by T / t are 0.05 or more and 0.
　The toothbrush according to any one of claims 1 to 8 , which is .35 or less .
[Claim 10]
　Assuming that the maximum width of the inverted portion in the second direction is L and the maximum width of the
　elastically deformed portion in the second direction is
　W, the values ​​represented by L / W are 0.05 or more and 0.35.
　The toothbrush according to any one of claims 1 to 9 , which is as follows .
[Claim 11]
　The toothbrush according to any one of claims 1 to 10, 　wherein the inverted portion is formed of a hard resin, and
　a part of the elastically deformed portion is formed of a resin having a hardness different from that of the hard resin.
..
[Claim 12]

　The toothbrush according to claim 11, 　wherein the rigid resin has a flexural modulus of 1500 MPa or more and 3500 MPa or less .
[Claim 13]

　The toothbrush according to claim 11 or 12, 　wherein a part of the elastically deformed portion is made of a soft resin .
[Claim 14]

　The toothbrush according to any one of claims 1 to 13 　, wherein the gap is a through hole extending in the first direction .