[0001]The present invention relates to a rolling bearing and an air turbine bearing unit and dental air turbine handpieces.
BACKGROUND
[0002]
　In dental treatment, air turbine handpiece small and light is frequently used.
　Figure 25 shows the dental air turbine handpiece 120 as an example. The dental air turbine handpieces 120 includes a grip portion 121, a head portion 122 provided at the tip portion of the grip portion 121, a. Surgeon with the grip portion 121, for example, performs the cutting of the tooth.
　Air turbine handpiece of this kind, head housing (hereinafter, simply referred to as "housing") having an air supply port and the exhaust port in the interior of, the rotary shaft having a turbine blade for receiving the compressed air from the air supply port It is rotatably accommodated. Rotary shaft is supported by a high speed rotatable housing via a rolling bearing. While the treatment tool attached to the rotary shaft is rotated at high speed, the operator by operating the air turbine handpiece, cutting or the like of the tooth it is performed.
[0003]
　Patent Document 1, an air turbine handpiece is described in which a heat-resistant mechanical seal to the rolling bearing. The heat-resistant mechanical seal, when the pressure caused by the compressed air is acting, that is, when the rotary shaft having a turbine blade is rotating, elastically deformed to contact the rolling bearing shields the compressed air. Thus, the influence of the compressed air acting on the time of use, to prevent the lubricating oil inside the rolling bearing will exits. Meanwhile, when the pressure caused by the compressed air is not acting, that is, when the rotating shaft is not rotating, the process returns to the original state so that non-contact rolling bearing. This eliminates the frictional resistance between the heat-resistant mechanical seal at the beginning and rotation rolling bearing, thereby enabling smooth start of the treatment tool which is attached to the rotating shaft.
CITATION
Patent Document
[0004]
Patent Document 1: Japanese Patent 2003-135486 JP
Summary of the Invention
Problems that the Invention is to Solve
[0005]
　Air turbine handpiece, about 400,000 min -1 are used in ultra-high speed rotation of. On the other hand, when the rotation stopping operation is performed, i.e., when the supply of compressed air is stopped, immediate stoppage of rotation of the rolling bearing is obtained.
　However, the rolling bearing described in Patent Document 1, when the pressure acting by compressed air in heat resistance mechanical seal, that is, when the rotary shaft turbine blade is mounted is rotating, supports the rotating shaft rolling heat resistance mechanical seal is in contact with the, has a structure to increase the resistance of the rolling bearing. Therefore, approximately 400,000 min -1 unsuitable for use in ultra-high speed rotation of. Further, the heat resistance mechanical seal when stopping the supply of compressed air is not in contact with the rolling bearing, the frictional resistance of the rolling bearing is reduced, it is disadvantageous also on to immediately stop the rolling bearing. Further, the contact shield composed of a seal member and the seal support ring described in Patent Document 1, large rigidity of the contact shield is approximately 400,000 min -1 when used in ultra-high speed rotation of a large air pressure there is a problem that it is necessary to.
[0006]
　The present invention has been made in view of the above problems, the first object, than conventional and more rapid ultra high speed its rapid stop and both possible rolling bearings and air turbine bearing unit as well as It is to provide a dental air turbine handpieces.
　A second object is to provide an ultra-high speed rotation, and quickly capable of stopping the rolling bearing and an air turbine bearing unit and dental air turbine handpieces rotation of a small air pressure.
Means for Solving the Problems
[0007]
　The above object of the present invention is achieved by the following constitutions.
(1) and the turbine blades rotated by compressed air, the turbine blades are fixed integrally with the rotary shaft that is attachable to the tool, the rolling bearing and rotatably supporting said rotary shaft relative to the housing, the a air turbine bearing unit comprising,
　the rolling bearing comprises an outer ring fixed to the housing, an inner ring fixed to the rotating shaft, rollably disposed between the inner ring and the outer ring a plurality of rolling elements,
　fixed to the inner peripheral surface of the outer ring, and a seal member for sealing the bearing inner space between the inner ring and the outer ring,
　the supply downstream of the compressed air of the outer peripheral surface of the inner ring shaft end side has an inclined surface whose diameter from the large diameter toward the supply direction downstream side of the axial compression air,
　the sealing member has no metal core, consisting only of an elastic material, in the radial direction extending A base, extending from a radially inner end of the base, has a lip portion inclined to the feed direction downstream of the compressed air toward the radially inner side,
　when the compressed air does not act, the sealing member the inclined surface of the supply direction upstream of the compressed air of the lip portion contacts the inclined surface of the inner ring,
　when the compressed air acts, compressed air of the lip portion of the sealing member than when the compressed air does not act the contact area between the inclined surface and the inner ring of the inclined surface of the supply direction upstream side becomes small, air turbine bearing unit.
(2) and turbine blades rotated by compressed air, the turbine blades are fixed integrally with the rotary shaft that is attachable to the tool, the rolling bearing and rotatably supporting said rotary shaft relative to the housing, the a air turbine bearing unit comprising,
　the rolling bearing comprises an outer ring fixed to the housing, an inner ring fixed to the rotating shaft, rollably disposed between the inner ring and the outer ring a plurality of rolling elements,
　fixed to the inner peripheral surface of the outer ring, and a seal member for sealing the bearing inner space between the inner ring and the outer ring,
　of the outer peripheral surface of the inner ring, at least the lip portion portion of contact has a cylindrical surface,
　said sealing member has no metal core, consisting only of an elastic material, a base extending in the radial direction, extends from a radially inner end of said base portion, radially inwardly toward Wherein a lip portion that is inclined to the feed direction downstream of the compressed air, has, according to buy
　when the compressed air is not applied, the inner peripheral surface of the lip portion of the seal member is in contact with the cylindrical surface of the inner ring,
　the when compressed air is applied, the contact area of the inner peripheral surface of the lip portion of the sealing member than when the compressed air does not act and the inner ring of the cylindrical surface is reduced, air turbine bearing unit.
(3) when the compressed air is applied, the seal member comprises an outer peripheral surface of the non-contact state of the inner ring, air turbine bearing unit according to (1) or (2).
(4) (1) with an air turbine bearing unit according to any one of - (3), a dental air turbine handpieces.
Effect of the invention
[0008]
　According to the rolling bearing and the air turbine bearing unit and dental air turbine handpieces of the present invention can achieve both than the conventional and more rapid ultra high-speed rotation and its quick stop.
　Further, according to the rolling bearing and the air turbine bearing unit and dental air turbine handpieces present invention, since it is possible that the substantially annular member lower seal rigidity consists only of the elastic member, with less air pressure, the rotation of the rolling bearing it is possible to up the number.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009]
FIG. 1 is a fragmentary cross-sectional view of a dental air turbine handpiece of the first embodiment.
FIG. 2 is a partial sectional view showing a stop state of the rolling bearing of the first embodiment.
It is a cross-sectional view of FIG. 3 the sealing member.
4 is a partial cross-sectional view showing an operating state of the rolling bearing of the first embodiment.
5 is a partial sectional view showing a rolling bearing of the second embodiment.
6 is a partial sectional view showing a rolling bearing of the third embodiment.
7 is a partial sectional view showing a rolling bearing of the fourth embodiment.
8 is a partial sectional view showing a rolling bearing of the sixth embodiment.
It is a [9] a cross-sectional view for explaining a contact angle of the seal member shown in FIG.
FIG. 10 is a partial cross-sectional view showing a rolling bearing of the sixth embodiment.
11 is a partial cross-sectional view of a rolling bearing according to a modification of the sixth embodiment in the operating state.
12 is a partial cross-sectional view showing a rolling bearing of the seventh embodiment.
13 is a front view of the seal member illustrating the other embodiment.
14 is a front view of the seal member illustrating the other embodiment.
15 is a front view of the seal member illustrating the other embodiment.
16 is a front view of the seal member illustrating the other embodiment.
17 is a front view of the seal member illustrating the other embodiment.
18 is a front view of the seal member illustrating the other embodiment.
19 is a front view of the seal member illustrating the other embodiment.
FIG. 20 is a front view of the seal member illustrating the other embodiment.
21 is a front view of the seal member illustrating the other embodiment.
Is a sectional view taken along each of the A-A line in FIG. 22A] FIGS. 19 to 21.
Is a sectional view taken along each line B-B in FIG. 22B] FIGS. 19 to 21.
FIG. 23 is a partial cross-sectional view of a rolling bearing of the angular type counterbore formed in the outer ring.
It is a partial cross-sectional view of FIG. 24 of the angular type counter bore is formed in the inner ring rolling bearing.
[FIG 25 is a schematic side view of a dental air turbine handpieces.
DESCRIPTION OF THE INVENTION
[0010]
　It will be described in detail with reference to embodiments of the air turbine for rolling bearings and air turbine bearing unit according to the present invention with reference to the drawings. In the following description, illustrating a case where the air turbine bearing unit of the present invention is applied to a dental air turbine handpieces in the Examples, other uses can also be applied to, for example, home appliances such as a motor.
[0011]

　FIG 1 is a fragmentary cross-sectional view of a dental air turbine handpiece of the first embodiment.
　Air turbine bearing unit 100 is mounted on the head portion 201 of dental air turbine handpieces 200. Air turbine bearing unit 100 includes a turbine blade 103 that rotates by receiving compressed air, the turbine blades 103 are fixed together, the tool at one end (e.g., a dental treatment tool) and the rotary shaft 101 can be attached to the housing 105 pair of air turbines rolling bearing 1 rotatably supporting the rotary shaft 101 with respect to (or later, the rolling bearing to be referred) provided with a.
[0012]
　Each rolling bearing 1 is supported in the housing 105 through a rubber ring 113 which is mounted on an annular recess 109 and 111 of the housing 105. Also, one of the rolling bearing 1 is biased by a spring washer 115 to the other of the rolling bearing 1 side.
[0013]
　Figure 2 is a partial cross-sectional view illustrating a stop state of the rolling bearing of the first embodiment.
　Rolling bearing 1 includes an outer ring 10 having an outer ring raceway surface 10a, an inner ring 20 having an inner ring raceway surface 20a, a plurality of balls (rolling elements) rollably arranged between the outer ring 10 and inner ring 20 3 a bearing comprising a retainer 5 for retaining a plurality of balls 3 rolling freely, respectively, the. The present invention is not limited to the bearings in the illustrated example, it may be a bearing of the angular contact type. The outer ring 10 is held within the housing 105 via the rubber ring 113 shown in FIG. The inner ring 20 is fixed to the rotary shaft 101. Cage 5 is a so-called crown type cage, substantially annular rim portion 7, the supply direction upstream of the compressed air than the balls 3, that is, positioned to the right side in FIG. 2. Arrow P in the drawing indicates the direction of flow of compressed air.
[0014]
　Between the outer ring 10 and inner ring 20, and can be sealed over the entire periphery of the bearing inner space S between the outer peripheral surface 21 of the inner peripheral surface 11 and the inner ring 20 of the outer ring 10 sealing member 30 of annular shape provided ing. Sealing member 30 is made of a comprised solely of elastic resilient material not provided with the metal core. The outer peripheral portion of the seal member 30 is fixed by the ring 40 fixed to the groove 13 formed on the inner peripheral surface of the outer ring 10, an inner peripheral portion which is elastically deformable in the axial direction and radial direction of the bearing.
[0015]
　The elastic member constituting the seal member 30, for example, Shore A hardness (JIS K 6253) of 60 to 90 acrylic rubber, the Shore A hardness of 60 to 90 fluorine rubber or the like can be used. Sealing member 30, by using the above materials, obtained suitable elastic properties, durability is also improved wear resistance.
　In particular, the dental air turbine handpieces, since the high temperature cleaning and sterilization after use are subjected, acrylic rubber or fluorine rubber is suitable with a water resistance and steam resistance (high temperature and high humidity) resistance.
[0016]
　Sealing member 30 is provided downstream side bearing end of the compressed air than the balls 3, that is, provided in the bearing end of the left side in FIG. 2. That is, the seal member 30 is provided on one axial end portion opposite to the compressed air supply side of the bearing internal space S (the inlet of the compressed air). The inner circumferential surface 11 of the outer ring 10, a groove portion 13 for fixing the sealing member 30 is formed. The groove 13, the sealing member 30 is fixed by the retaining ring 40. The shape of the seal member 30 is not limited to the annular shape but may be other shapes as long as substantially annular, as will be described later.
[0017]
　The outer peripheral surface 21 of the inner ring 20 is provided downstream side of the compressed air, namely, it has an inclined surface 23 on the end portion of the left side in FIG. 2. The inclined surface 23 is formed from a larger diameter toward the supply direction downstream side in the axial direction the compressed air to the inclined conical shape such that the diameter.
[0018]
　Figure 3 is a cross-sectional view of the seal member 30.
　Sealing member 30 has a base portion 31 of annular shape extending in the radial direction, it extends from a radially inner end of the base 31, elastically deformable lip portion 33 which is inclined to the feed direction downstream of the compressed air toward the radially inner side and, with a. The inclination angle θ relative to the base 31 of the inclined surface of the supply direction upstream of the compressed air of the lip 33 of the seal member 30, 30 ° ~ 80 °, and preferably 40 ° ~ 70 °, more preferably 45 ° ~ 65 ° to. For example, the inclination angle θ by setting the 55 ° within the above range, the frictional resistance, the balance of the flow of compressed air is improved. Contact resistance may become excessive when the inclination angle θ is smaller than the above range, excessive flow resistance of the compressed air is greater, not obtained the intended performance will be described later.
[0019]
　Sealing member 30, as shown in FIG. 2, it is inserted into the groove 13 together with the wheels 40 stop the radially outer end of the base portion 31 is fixed to the groove 13. Groove 13 has a tapered surface 15 inclined radially outwardly toward the axially inward, axially inward from the tapered surface 15, and axially inner surface 17 of the axial side surface of the base portion 31 are in contact with the tapered surface 15 having a groove bottom surface, a cylindrical inner connecting the axially inner surface 17 and. Retaining ring 40, for example, the outer diameter as C-RING is enabled contracted by the elastic deformation. Wheel 40 locking the base 31 of the seal member 30 is fixed so as to be sandwiched between the tapered surface 15 and the axial inner surface 17. The tapered surface 15, a line contact state outer diameter end of the axially outer retaining ring 40 along the circumferential direction. In this state, the retaining ring 40 has an outer diameter which is reduced in diameter than the free state by elastic deformation. Pressing force generated by the elastic deformation presses the tapered surface 15, it generates a force pressing the retaining ring 40 radially outward, the force to press the retaining ring 40 axially inwardly. By force of pressing the retaining ring 40 axially inwardly presses the seal member 30 in the axial direction in the side surface 17, securing the sealing member 30 to the outer ring 10. Incidentally, the retaining ring 40, in addition a cross-sectional rectangular shape may be a circular cross section. Further, an inclined surface is provided on the retaining ring 40, a groove 13 and a rectangular cross-section, it may be configured pressed against the inclined surface of the wheel 40 to stop the corners of the rectangular cross section groove 13.
[0020]
　Lip 33 is inclined in the feed direction downstream of the compressed air (axially outward) toward the radially inward inclined surface of the supply direction upstream of the compressed air is in contact with the inclined surface 23 of the inner ring 20. Inclination angle θ of the inclined surface of the supply direction upstream of the compressed air of the lip portion 33 has a smaller angle than the inclination angle of the inclined surface of the inclined surface 23 of the inner ring 20. Therefore, the lip portion 33 toward the inner diameter side, the amount of elastic deformation is increased.
[0021]
　Figure 4 is a partial cross-sectional view showing an operating state of the rolling bearing of the first embodiment.
　Additional air turbine bearing unit 100 that is configured (see FIG. 1), when compressed air to the turbine blades 103 by the driving of dental air turbine handpieces 200 is supplied, as shown in FIG. 4, is supplied compressed air flows into the bearing inner space S, the pressure of the compressed air in the sealing member 30 acts was. Then, the sealing member 30 is elastically deformed toward the downstream side of the flow of compressed air. As a result, compared to the case where the pressure of the compressed air does not act, the contact area between the inclined surface 23 of the inner peripheral surface 35 and the inner ring 20 of the lip portion 33 is reduced. That is, the lip portion 33 is an open state for communicating compressed air.
[0022]
　Sealing member 30, since only made of an elastic material without a metal core, and is generally elastically deformable structure. Accordingly, when compressed air acts beyond a certain pressure on the sealing member 30, the inner peripheral portion of the seal member 30 is elastically deformed toward the axially outer side, the inclination of the feed direction upstream of the compressed air of the lip portion 33 contact area between the inclined surface 23 of the face and the inner ring 20 is reduced.
[0023]
　Thus, in this configuration, even when the supply pressure of the compressed air is relatively small, the lip portion 33 of the sealing member 30 is surely elastically deformed, thereby reducing the contact area.
[0024]
　Thus, can be started smoothly air turbine, it can be reduced frictional resistance between the seal member 30 and the inner ring 20, about 400,000 min of the rotation shaft 101 -1 can achieve ultra high-speed rotation of. Moreover, by the inclined surface 23 is provided at the end of the supply direction downstream of the compressed air in the outer peripheral surface 21 of the inner ring 20, the compressed air flow passing between the lip portion 33 and the inclined surface 23 becomes smooth further it can be realized high-speed ultra high speed than conventional.
[0025]
　On the other hand, when the supply of compressed air by the drive stopping of dental air turbine handpieces 200 to the turbine blade 103 is stopped, the pressure of the compressed air acting on the lip portion 33 is reduced. Then, the inclined surface of the supply direction upstream of the compressed air of the lip portion 33 is in surface contact while generating a pressing force to the inclined surface 23 of the inner ring 20. Accordingly, the lip portion 33 functions as a brake of the inner ring 20.
[0026]
　Further, the inclined surface of the supply direction upstream of the compressed air of the lip 33 of the seal member 30 is, due to the construction in contact with the inclined surface 23 of the inner ring 20, with a slight axial displacement of the lip 33, the lip portion 33 it can be reduced greatly the frictional resistance of the inclined surface 23. Further, when stopping, due to the large contact area of ​​the lip portion 33 and the inclined surface 23, so make a big frictional resistance, it is excellent in braking effect. Further, it is possible to obtain a high sealing effect at the time of stop due to a large contact area of ​​the lip portion 33 and the inclined surface 23. In other words, at a pressure of less compressed air than the conventional structure can reduce the contact pressure, can be realized further improvement of the rotational speed of the rotary shaft 101 and the stop time reduction and at the same time. Balance between speed and braking performance of the rotary shaft 101 is optimally tilted or inclined surface 23, by adjusting the inclination angle of the inclined surface of the supply direction upstream of the compressed air of the thick and the lip portion 33 of the seal member 30 It can be set.
[0027]
　Particularly in dental air turbine handpieces 200, very fast rotation is required when cutting the teeth, within 2 seconds when stopping, preferably steep rotation stop performance of within 1 second is required. According to this construction, since the effect of shortening increases and stop time of the rotational speed can be obtained stably, can be significantly improved usability of dental air turbine handpieces 200.
[0028]
　At the time of driving of dental air turbine handpieces 200, since the compressed air is less likely to leak from the bearing, the noise during driving is reduced, a high quietness is obtained.
[0029]
　Further, as shown in FIG. 1, the rolling bearing 1 is a pair disposed on the rotary shaft 101, the seal member 30 is disposed in the axial end portion on the side opposite to the inlet of the compressed air of the outer ring 10. Thus, from between the adjacent pair of rolling bearings 1, by spraying lubrication, the lubricating oil can be supplied seal member 30 is not disposed from the bearing end side of each rolling bearing 1. Further, on the opposite side of the spray lubrication side since the seal member 30 is disposed, thereby preventing liquid leakage during lubrication from the rolling bearing 1 to the outside of the head portion 201.
[0030]
　Usually, the dental air turbine handpieces 200, high temperature cleaning and sterilization after use is subjected. Amount of lubricant within the rolling bearing 1 by this process is decreased, since the sealing member 30 is disposed only on one axial end portion of the rolling bearing 1 can be easily supply the lubricating oil from the other axial end. Therefore, it the rolling bearing 1 is always good lubrication state, stable rotation of the rotating shaft 101 becomes possible.
[0031]

　Next, a second embodiment of the air turbine bearing unit 100. In the following description, the same members or portions as in the first embodiment, by the same reference numerals, simplify the description, or omitted.
[0032]
　Figure 5 is a partial cross-sectional view showing an operating state of the rolling bearing of the second embodiment.
　Sealing member 30A of this embodiment, the compressed air flows into the bearing inner space S, when the pressure of the compressed air to the sealing member 30A acts, the inclined surface of the supply direction upstream of the compressed air of the lip portion 33 and the inner ring the inclined surface 23 of the 20 completely becomes a non-contact state with each other. Then, the non-contact state is maintained by the compressed air flowing between the lip portion 33 and the inclined surface 23.
[0033]
　On the other hand, when the pressure of the compressed air does not act on the sealing member 30A is the inclined surface of the supply direction upstream of the compressed air of the lip portion 33 contacts the entire periphery on the inclined surface 23 of the inner ring 20.
[0034]
　According to the sealing member 30A having the above structure, when the pressure of the compressed air acts on the sealing member 30A, the frictional resistance caused by contact between the sealing member 30A and the inner ring 20 is completely eliminated, in the first embodiment described above further ultra high-speed rotation of the faster than can be achieved. Other advantages are the same as the first embodiment.
[0035]

　Next, a third embodiment of the air turbine bearing unit 100.
　6 is a partial sectional view showing a rolling bearing of the third embodiment.
　Rolling 1C of the present embodiment, it extended to axially outward than the outer ring 10 and inner ring 20A, and a seal member 30C is protruded outwardly in the axial direction than the outer ring 10.
[0036]
　The inner ring 20A, the first, as in the second embodiment, the end portion of the outer peripheral surface 21 serving as a supply direction downstream side of the compressed air, that is, the inclined surface 23 on one end portion of the outer peripheral surface 21 of the left side in FIG. 6 having. The inclined surface 23 is formed from a larger diameter toward the supply direction downstream side in the axial direction the compressed air to the inclined conical shape such that the diameter.
[0037]
　The sealing member 30C is inclined surface of the supply direction upstream of the compressed air of the lip portion 33 comes into contact with the inclined surface 23 of the inner ring 20A in the axial direction outside than the outer ring 10.
[0038]
　According to this configuration, the inclination angle θ3 from the radial direction of the inclined surface of the supply direction upstream of the compressed air of the lip portion 33, first mentioned above, can be made larger than the inclination angle θ in the case of the second embodiment. Therefore, perform opening and closing operations of the lip portion 33 with compressed air more smoothly. Other advantages are, first described above is similar to the second embodiment.
[0039]

　Next, a fourth embodiment of the air turbine bearing unit 100.
　Figure 7 is a partial sectional view showing a rolling bearing of the fourth embodiment.
　Rolling 1D of the present embodiment, the small diameter portion 61 is formed at one end of the outer peripheral surface 21 serving as a supply direction downstream side of the compressed air of the inner ring 20B. The outer peripheral surface 21, a shoulder portion 65 connected to the inner ring raceway surface 20a, between the small-diameter portion 61, the stepped surface 67 is formed. Step surface 67, the steep wall in the radial direction becomes formed over the entire circumference.
[0040]
　Sealing member 30D is an elastically deformable flat disk shape, so the radially inner portion of the feed direction upstream side of the compressed air is contacted in an elastically deformed state so as to have a pressing force in the axial direction on the wall surface of the stepped surface 67 It is attached to the groove 13 of the outer ring 10. Incidentally, a sealing member 30D is elastically deformable flat disk-shaped in the illustrated embodiment, the stepped surface 67 are substantially perpendicular walls axially not limited thereto. For example, the radially inner portion and a stepped surface 67 of the sealing member 30D is either one, or both, may be slightly inclined from the radial direction.
[0041]
　According to this configuration, in the case the lip portion 33 of the sealing member 30D is, due to a configuration in contact with the stepped surface 67 and the axial direction of the inner ring 20B, which contacts the contact pressure between the seal member 30D and the stepped surface 67 in the radial direction It can be reduced compared to. Thus, the processability of the sealing member 30D and the inner ring 20B is simplified, it is possible to reduce the manufacturing cost can further obtain the same advantageous effects as the first to third embodiments described above.
[0042]

　Next, a fifth embodiment of the air turbine bearing unit 100.
　Rolling bearing according to the present embodiment, except that the retainer 7A to outer ring guide type is the same as that of the first embodiment.
[0043]
　According to this configuration, the retainer is disposed on the outer ring side, the inner gap between the inner peripheral surface of the cage and the inner ring of the outer circumferential surface becomes wider than the outer clearance of the outer ring side. Then, when the compressed air flows into the bearing inner space, compressed air passes through mainly a plurality of balls located between the outer ring and the inner ring of the (rolling elements), an inner gap which becomes radially inner space It flows to the sealing member side, devoted blown to the lip portion of the seal member.
[0044]
　Sealing member, by compressed air to the lip portion is blown directly against the supply pressure of the compressed air even if relatively low, a reliably elastically deformable. Thus, the opening and closing operation of the sealing member by compressed air, can be carried out more smoothly and high responsiveness.
[0045]

　Next, a sixth embodiment of the air turbine bearing unit 100.
　Figure 8 is a partial sectional view showing a rolling bearing of the sixth embodiment.
　Rolling 1E of the present embodiment, is different that the shape of the sealing member 30E of the lip portion 33, of the outer peripheral surface 21 of the inner ring 20C, except at least portions of the lip portion 33 are in contact with a cylindrical surface, the 1 is the same as the configuration of the embodiment.
[0046]
　Lip 33 of the sealing member 30E is, (in FIG. 8, a direction from right to left) supply direction downstream of the compressed air toward the radially inner side has a conical shape inclined to. That is, the lip portion 33 is inclined axially outwardly toward the radially inner side. Then, the inner peripheral surface of the radially inner peripheral end of the lip portion 33 of the sealing member 30E has a inner cylindrical surface parallel to the axis. The cylindrical surface among a inner peripheral surface of the lip portion 33 is in contact with the cylindrical surface of the outer peripheral surface 21 of the inner ring 20C. Thus, the sealing member 30E seals the bearing inner space S between the outer peripheral surface 21 of the inner peripheral surface 11 and the inner ring 20C of the outer ring 10.
　In the Figure 8 and 9 are shown different shapes of the lip portion 33. Thus, the lip portion 33, as shown in FIG. 8, may be a uniform thickness radially inward, as shown in FIG. 9, progressively thinner toward the radially inner side it may become.
[0047]
　Figure 10 is a partial cross-sectional view showing an operating state of the rolling bearing of the sixth embodiment. Arrow P in the drawing indicates the direction of flow of compressed air.
　To drive the air turbine handpiece, when compressed air is supplied to the turbine blades, the bearing inner space S compressed air toward the left from the right in FIG. 10 flows. The compressed air acts on the sealing member 30E, is elastically deformed so as to increase the inner diameter of the lip portion 33. Therefore, when the compressed air acts on the contact area between the outer peripheral surface 21 of the inner peripheral surface and the inner ring 20A of the radially inner peripheral end of the lip portion 33 compared to when compressed air does not act is reduced. In the example of FIG. 10, and the outer peripheral surface 21 of the inner peripheral surface and the inner ring 20C of the radially inner peripheral end of the lip portion 33 has a non-contact state, these contact areas is zero. That is, the lip portion 33 is opened. Also, as in the example of FIG. 11, when the compressed air is applied, while maintaining the outer peripheral surface 21 of the inner peripheral surface and the inner ring 20C of the radially inner peripheral end of the lip portion 33 of the contact state, compressed air is acting may be a contact area becomes smaller configuration of the outer peripheral surface 21 of the inner peripheral surface 35 and the inner ring 20C of the lip portion 33 compared to when not.
[0048]
　In particular, in this embodiment, the seal member 30E, since only made of an elastic material without a metal core, and is generally elastically deformable structure. Accordingly, when compressed air acts beyond a certain pressure on the sealing member 30E, the inner peripheral portion of the seal member 30 toward the axially outward elastically deformed, the inclined surface of the inner peripheral surface and the inner ring 20 of the lip portion 33 contact area with the 23 is small.
[0049]
　Meanwhile, in order to stop the dental air turbine handpieces, when stopping the supply of compressed air, since the compressed air does not act on the lip 33, the lip portion 33 returns to the state shown in FIG. The inner peripheral surface of the lip portion 33 is a surface contact while generating a pressing force to the outer peripheral surface 21 of the inner ring 20C. That is, the lip portion 33 is closed. Thus, the lip portion 33 serves as a brake of the inner ring 20C and the rotating shaft 101 to which the inner ring 20C is fixed (see FIG. 1), it is possible to stop the rotation shaft 101 rapidly.
[0050]
　The shape of the lip portion 33, by tilting the feed direction downstream of the compressed air toward the radially inner side, because it is elastically deformable inclined shape by the action of compressed air, the lip by compressed air the opening and closing operation of the parts 33 can be performed with good sensitivity.
[0051]
　As shown in FIG. 9, the inclination angle θ of the lip portion 33 of the sealing member 30E, preferably it is set to 35 ~ 55 °. Thus, when compressed air acts, air acts efficiently to the lip portion 33, it is possible to open the sealing member 30E smoothly, as a result, it is possible to super high-speed rotation at a pressure of less compressed air .
[0052]
　Also, of the outer peripheral surface 21 of the inner ring 20C, the portion of at least the lip portion 33 are in contact with a cylindrical surface, it is possible to increase the contact area of ​​the inner peripheral surface of the outer peripheral surface 21 and the lip portion 33 of the inner ring 20C, it is possible to improve the braking function by the lip 33. In particular, in this embodiment, the inner peripheral surface of the lip portion 33, since the surface contact with the outer peripheral surface 21 of the cylindrical inner ring 20C, it is possible to further improve the braking function by the lip 33.
[0053]
　Incidentally, the radially inner peripheral surface of the lip portion 33 may be a substantially triangular cross-section. In that case, braking performance is inferior as compared with the case of surface contact, because the compressed air may be opened sealing member 30E with a slight elastic deformation when acting, be ultra high speed at a pressure of less compressed air it can.
[0054]

　Next, a seventh embodiment of the air turbine bearing unit 100.
　Figure 12 is a partial cross-sectional view showing a rolling bearing of the seventh embodiment.
[0055]
　If the sealing performance is obtained, as shown in FIG. 12, the inner ring 20D of the rolling bearing 1F extended to axially outward than the outer ring 10, extend axially outward from the outer ring 10 of the seal member 30F and it may be. In this case, the inner peripheral surface of the lip portion 33 of the sealing member 30F is in the axially outer than the outer ring 10 abuts against the outer peripheral surface 21 of the inner ring 20D. According to this configuration, it is possible to increase the slope of the lip section 33, it is possible to perform opening and closing operations of the lip portion 33 with compressed air more easily.
[0056]

　The present invention is not limited to the above embodiments, and suitable modifications, improvements and so on can be made.
[0057]
　The cage 5 for use in the rolling bearing 1 of the first to seventh embodiments, the rim portion 7 of one side, are disposed in the supply direction upstream of the compressed air than the balls 3, not limited to this, the rim part 7 may be configured to arranged on the sealing member side of the axially opposite side.
[0058]
　The sealing member is to be disposed only on one axial end of the rolling bearing 1, the groove 13 and the outer ring 10, the inclined surface 23 of the inner ring 20,20A in the first to fifth embodiment, the stepped surface 67, it is formed only in one axial end, not limited thereto, and may be configured to be formed symmetrically in the axial direction other end side. As a case, the one of the pair of grooves 13 is not used, also, in the configuration of the first to fifth embodiments, so that one of the pair of inclined surfaces or the step is not used. In this case, in the assembly process of the rolling bearing, there is no need to be aware of the direction of assembly, can be simplified working process.
[0059]
　The sealing member, the thickness of the lip portion may be constant thickness, or may be gradually reduced radially inward.
　The shape of the inner diameter side end portion of the lip portion 33 of the seal member 13, as shown in FIG. 14, or a substantially triangular shape in a substantially elliptical shape. Other examples of sealing member 30 to be described below, the aforementioned seal member 30A, 30B, 30C, 30D, 30E, it can be similarly applied to 30F.
[0060]
　Further, the inner diameter side end portion of the lip portion 33 may be provided at least one vent hole 41 as shown in FIG. 15 may be provided with at least one notch 43 as shown in FIGS. 16 to 18 . In FIG. 15, an example in which a single circular vent holes 41 are provided is shown, the vent hole 41 may be two or more, the shape of the vent hole 41 is not limited to a circle. Also, in the FIGS. 16 to 18, two each, four, and eight notches 43 is shown an example provided at equal circumferential intervals, the number and circumferential spacing of the incisions 43 but it is not limited to this.
[0061]
　Further, as shown in FIGS. 19 to 21, the inner diameter side end portion of the lip portion 33 is notched circumferentially continuous inner diameter side end portion of the lip portion 33, portions on the outer peripheral surface 21 of the inner ring 20 it may be contacted.
[0062]
　Here, illustrating the case of a sealing member 30E of the sixth embodiment as an example, FIG. 22A is a sectional view taken along each of the A-A line in FIGS. 19 to 21, FIG. 22B, FIG. 19 to it is a sectional view taken along each line B-B in FIG. 21.
[0063]
　Thus, the present invention is not limited to the above embodiments, and combining the respective components of the embodiments with each other, the description, and based on the well known those skilled in the art to make modifications, applications it is also the place where schedule of the present invention that, within the scope for which protection is sought.
　For example, in the above example uses a ball bearing as the rolling bearing is a roller bearing or the like, or may be a rolling bearing of any other type. Further, the rolling bearing of the example is an inner ring rotating type, although the seal member is fixed to the outer ring, a seal member fixed to the inner ring, it may be configured to contact the outer race. Further, by changing the retainer geometry, it may be configured to spread the bearing width than the above example.
[0064]
　Further, the rolling bearing of the present invention may be angular type roller bearing.
　Figure 23 is a partial sectional view showing a rolling bearing of the angular type counterbore 81 is formed in the outer ring 10A. The outer ring 10A and the inner ring 20, is applied to the inclined surface 23 and the seal member 30 in the rolling bearing 1 of the first embodiment as an example.
　Figure 24 is a partial sectional view showing a rolling bearing of the angular type counterbore 83 is formed in the inner ring. In this case also the outer ring 10 and inner ring 20E, is applied to the inclined surface 23 and the seal member 30 in the rolling bearing 1 of the first embodiment as an example.
[0065]
　As shown in FIGS. 23 and 24, even rolling angular type, above same effect can be obtained. Incidentally, FIG. 23, FIG. 24 is an example, a rolling bearing 1A ~ 1F of other embodiments may be a rolling bearing of the angular type having the above structure, even if the addition of the angular type other forms the rolling bearing good.
[0066]
　This application is Japanese Patent Application filed March 7, 2016 (Japanese Patent Application No. 2016-43309), Japanese Patent Application filed May 19, 2016 (Application No. 2016-100601), and on June 29, 2016 Japanese Patent application filed (Japanese Patent application No. 2016-129149), the contents of which are incorporated herein by reference.
DESCRIPTION OF SYMBOLS
[0067]
　　1,1B, 1C, 1D, 1E, 1F rolling bearing
　　3 balls (rolling
　　elements) 5 retainer
　　7 rim
　10,10A outer race
　11 inner circumferential surface
　13 groove
　15 tapered surface
　17 axially inside surface
　20, 20A, 20B, 20C , 20D, 20E the inner ring
　21 outer circumferential surface
　23 inclined surface
　30,30A, 30C, 30D, 30E, 30F sealing member
　31 base
　33 lip part
　35 inner circumferential surface
　40 retaining ring
　41 vent
　43 cut
　67 stepped surface
100 air turbine bearing unit
200 dental air turbine handpiece
201 head portion
　S inside the bearing space

WE CLAIM

[Requested item 1]
　A turbine blade which rotates by receiving compressed air, wherein the turbine blades are fixed together, the air turbine having a rotary shaft that is attachable to the tool, the rolling bearing and rotatably supporting said rotary shaft relative to the housing, the a use bearing unit,
　the rolling bearing comprises an outer ring fixed to the housing, an inner ring fixed to the rotary shaft, a plurality of rolling rollably disposed between the inner ring and the outer ring and body,
　fixed to the inner peripheral surface of the outer ring, and a seal member for sealing the bearing inner space between the inner ring and the outer ring,
　the supply direction downstream of the compressed air of the outer peripheral surface of the inner ring shaft end has an inclined surface whose diameter from the large diameter toward the supply direction downstream side of the axial compression air,
　the sealing member has no metal core, a base made of only an elastic material, extending radially Anda lip portion inclined to the feed direction downstream of the compressed air according to extend from a radially inner end of the base toward the radially inner side,
　when the compressed air is not applied, the lip portion of the sealing member the inclined surface of the supply direction upstream of the compressed air into contact with the inclined surface of the inner ring,
　when the compressed air is applied, the supply direction of the compressed air of the lip portion of the sealing member than when the compressed air does not act the contact area between the upstream side of the inclined surface and the inner ring of the inclined surface is reduced, air turbine bearing unit.
[Requested item 2]
　A turbine blade which rotates by receiving compressed air, wherein the turbine blades are fixed together, the air turbine having a rotary shaft that is attachable to the tool, the rolling bearing and rotatably supporting said rotary shaft relative to the housing, the a use bearing unit,
　the rolling bearing comprises an outer ring fixed to the housing, an inner ring fixed to the rotary shaft, a plurality of rolling rollably disposed between the inner ring and the outer ring and body,
　fixed to the inner peripheral surface of the outer ring, and a seal member for sealing the bearing inner space between the inner ring and the outer ring,
　of the outer peripheral surface of the inner ring, at least portions of the lip portion is in contact There is a cylindrical surface,
said sealing member has no metal core, consisting only of an elastic material, a base extending in the radial direction, extends from a radially inner end of the base portion, toward its radially inward Anda lip portion inclined to the feed direction downstream of the compressed air I,
　when the compressed air is not applied, the inner peripheral surface of the lip portion of the seal member is in contact with the cylindrical surface of the inner ring,
　the when compressed air is applied, the contact area of the inner peripheral surface of the lip portion of the sealing member than when the compressed air does not act and the inner ring of the cylindrical surface is reduced, air turbine bearing unit.
[Requested item 3]
　When the compressed air is applied, the seal member comprises an outer peripheral surface of the non-contact state of the inner ring, air turbine bearing unit according to claim 1 or claim 2.
[Requested item 4]
　With an air turbine bearing unit according to any one of claims 1 to 3, dental air turbine handpieces.