JP5775904B2 - Air motor and medical handpiece - Google Patents

Description

  The present invention relates to an air motor and a medical handpiece having the air motor assembled thereto.

  Patent Document 1 discloses a vane type air motor (hereinafter referred to as “air motor”) and one of medical (dental) handpieces incorporating the air motor. This air motor has a cylindrical housing (housing). On the inner side of the housing, there is a rotor supported rotatably about the central axis of the housing, and an inner peripheral surface centered on an eccentric shaft that is fixed around the rotor and is parallel to the central axis and is eccentric from the central axis A rotor case provided with is arranged. A plurality of grooves extending in the central axis direction are formed on the outer periphery of the rotor at predetermined intervals in the circumferential direction. Each groove accommodates a plate-like vane so that it can advance and retreat in the radial direction. Moreover, each vane is urged | biased by radial direction outer side by the spring arrange | positioned at the bottom part of a groove | channel, and the edge part of radial direction outer side is contacting the inner peripheral surface of a rotor case. A bearing that rotatably supports a proximal end portion of a shaft that supports the rotor and a bearing case that supports the bearing are fixed to the proximal end side of the rotor with respect to the central axis direction. The bearing case is formed with an air supply path and an exhaust path penetrating the base end side (handpiece base end side) end face and the end side (handpiece end side) end face of the bearing case. A valve member is disposed on the base end side of the bearing case. The valve member is formed with an air supply passage and an exhaust passage penetrating the proximal end surface and the distal end surface of the valve member, and is supported by the housing so as to be rotatable about the central axis.

  In the air motor configured as described above, during driving, pressure air is supplied from the air supply passage of the valve member to the rotor via the air supply passage of the bearing case, and the rotor is caused by the circumferential pressure difference received by the adjacent vanes. It rotates in a predetermined direction, and the rotation is transmitted to the tip of the handpiece to rotate the cutting tool. When reducing the rotation speed of the cutting tool, the valve member is rotated around the central axis. Thereby, the opposing area of the air supply path of a valve member and the air supply path of a bearing case reduces, and the quantity of the pressure air supplied to a rotor is restrict | squeezed.

  However, in the above-described air motor, the base end side end surface of the bearing case and the end side end surface of the valve member facing the bearing case are sealed only by contact between the two, so that a little amount of pressurized air passes between the opposing end surfaces. Was inevitable to leak. Therefore, particularly when the amount of air supplied to the rotor is reduced, a sufficient amount of pressurized air cannot be supplied from the air supply passage of the valve member to the air supply passage of the bearing case, and sufficient rotational torque cannot be obtained for the cutting tool. There was a problem.

Japanese Examined Patent Publication No. 62-11858

  In view of the above, an object of the present invention is to provide an air motor that prevents leakage of pressure fluid and that can provide sufficient rotational torque even at low speeds, and a medical handpiece including the air motor.

In order to achieve this object, an air motor according to the present invention and a medical handpiece assembled with the air motor include:
In a housing having a central axis,
A rotor provided with a shaft rotatably supported around the central axis and a rotor body fixed to the shaft;
A rotor case that is externally mounted on the rotor body and includes an inner peripheral surface that is parallel to the central axis and that is centered on an eccentric shaft that is separated from the central axis;
The rotor body is a plurality of vanes attached to the rotor, and is arranged at predetermined intervals in the circumferential direction around the central axis, and is capable of moving forward and backward in the radial direction around the central axis. Further, it is supported by the rotor body in a state of being urged radially outward and in contact with the inner peripheral surface of the rotor case, and moves in the circumferential direction of the central axis as the rotor body rotates. While moving in the radial direction, and has a plurality of vanes that form a space between each adjacent vane,
An air motor that rotates the rotor based on a difference in circumferential pressure received by two adjacent vanes when pressurized fluid is supplied to the space,
The air motor is
A proximal end and a distal side fixing member disposed on the proximal end side and the distal end side of the rotor main body with respect to the direction of the central axis and respectively fixed to the housing;
The proximal and distal sides of the rotor body are adjacent to the rotor body and between the rotor body and the fixing member, respectively, and block the pressure fluid leaking from the proximal and distal sides of the plurality of vanes. A proximal end side and a distal side bearing sheet,
With respect to the thrust direction parallel to the central axis, a thrust gap is formed between the thrust direction end surface portions on the base end side and the distal end side of the bearing seat and the thrust direction end surface portion of the fixing member facing the thrust direction end surface portion. Is formed,
With respect to the radial direction away from the central axis, a radial gap is formed between the radial direction outer peripheral portion on the proximal end side and the distal end side of the bearing seat and the radial direction end surface portion of the fixing member facing the radial direction outer peripheral portion. Formed,
The radial gap is smaller than the thrust gap.

  According to the air motor and the medical handpiece of the present invention configured as described above, the rotor case has a protruding portion receiving portion that encloses the rotor protruding portion, and the gap on the side surface between the rotor case and the rotor protruding portion is the rotor. Since it is smaller than the gap between the end surfaces of the case and the rotor protrusion, the pressure fluid is efficiently supplied to the rotor, and the rotational speed of the rotor is adjusted. In particular, even during low-speed rotation, a desired amount of pressurized fluid is efficiently supplied to the rotor, and a desired torque can be obtained. Moreover, such an effect can be realized with a simple configuration and processing.

The side view of a medical handpiece. The perspective view of the air motor assembled | attached to the handpiece of FIG. The longitudinal cross-sectional view of the air motor shown in FIG. The longitudinal cross-sectional view of the air motor shown in FIG. The longitudinal cross-sectional view of the air motor shown in FIG. The perspective view which removed a part of air motor shown in FIG. The perspective view of the rotor and rotor case seen from the terminal end. The perspective view of the rotor and rotor case seen from the base end side. The front view which looked at the base end side bearing case from the base end side. The perspective view of the valve member seen from the base end side. The perspective view of the valve member seen from the end side. The cross-sectional view of an air motor including a valve member. The figure which shows the relationship between a sealing member and a vent hole when a valve member is rotated. The fragmentary longitudinal cross-sectional view of the air motor shown in FIG.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following explanation, in describing the configuration shown in the drawings, terms indicating directions such as “up”, “down”, “left”, “right”, and other terms including them are used. However, the purpose of using these terms is to facilitate understanding of the embodiments through the drawings. Therefore, these terms do not necessarily indicate the direction in which the apparatus described in the embodiments is actually used, and these terms limit the technical scope of the invention described in the claims. Should not be interpreted.

[A: Configuration]
(1) Handpiece:
FIG. 1 shows a handpiece 10 which is one of dental treatment instruments. The handpiece 10 has such a size that a dentist or an operator such as a dental hygienist can hold it in his hand to perform dental treatment, and a cutting tool 12 is provided at the end of the handpiece body 11 shown on the left side in the figure. 1 can be detachably mounted, and the rear end (base end) shown on the right side of FIG. 1 is connected to a pressure fluid supply source (not shown). A vane type air motor (hereinafter referred to as “air motor”) 13 is integrally assembled on the proximal end side of the handpiece 10.

(2) Air motor:
The air motor 13 generates rotation using pressure air (compressed air) supplied from a pressure fluid supply source connected to the right end of the handpiece 10 in the drawing (hereinafter referred to as “base end”), The rotation is configured to be transmitted to the cutting tool 12, and the configuration described below is provided. The pressure fluid does not need to be compressed air, and may be a pressurized liquid.

(2-1) Housing:
FIG. 2 shows the external appearance of the air motor 13. As shown in the figure, the air motor 13 has a cylindrical housing (housing) 14. The housing 14 is configured by combining a distal-side housing portion 16 and a proximal-side housing portion 17 disposed along the central axis (first central axis) 15 thereof. An adjusting portion (volume cover) 18 for adjusting the rotational speed, rotational torque, and rotational direction of the air motor 13 is disposed between the distal and proximal housing portions 16 and 17. As will be described later, the adjusting unit 18 is externally mounted on the housing 14 so as to be rotatable about the central shaft 15 in order to operate a valve member (described later) that adjusts the air supply amount.

(2-2) Rotor:
As shown in FIGS. 3 to 5, a rotor (rotor) 20 is accommodated inside the housing 14. The rotor 20 includes a solid cylindrical rotor main body 21 having a central axis, and a shaft 22 extending from the rotor main body 21 to both sides (a distal end side and a proximal end side) along the central axis of the rotor main body 21. The rotor 20 is rotatably supported by a distal side bearing 23 and a proximal side bearing 24 in a state in which the central axis thereof coincides with the central axis 15 of the housing 14.

  As shown in FIGS. 7 and 8, the rotor body 21 has a columnar distal protrusion 25 in which the distal end and the proximal end protrude from the distal end and the proximal end, respectively (see FIG. 7). And a proximal-side protruding portion 26 (see FIG. 8). Then, bearing sheets 27 and 28 (see FIGS. 3 to 5) externally mounted on the shaft 22 are fixed to the distal side of the distal side protruding portion 25 and the distal side of the proximal side protruding portion 26, respectively.

  The rotor body 21 has a cylindrical outer peripheral surface 29 centered on the central axis 15. The cylindrical outer peripheral surface 29 has a predetermined interval (72 °) in the circumferential direction, and extends to the distal end surface 30 and the proximal end surface 31 of the rotor body 21 over the entire length thereof in parallel with the central axis 15 and the central axis. 15 has a plurality of radial grooves 32 extending in the radial direction. In the embodiment, the radiating groove 32 is formed so as to penetrate through the end surfaces of the distal-side protruding portion 25 and the proximal-side protruding portion 26, but does not penetrate the distal-side protruding portion 25 and the proximal-side protruding portion 26. The radiation groove 32 may be formed only in a region sandwiched between the side protrusion 25 and the base end protrusion 26. Each radiation groove 32 accommodates a rectangular plate-shaped blade (vane) 33 and a spring 34 (see FIG. 5) for urging the blade 33 radially outward.

  A rotor case 35 is disposed around the rotor 20. The rotor case 35 is a cylindrical member having a cylindrical outer peripheral surface 36 and a cylindrical inner peripheral surface 37, and is fixed to the housing in a state where the central axis of the cylindrical outer peripheral surface 36 coincides with the handpiece central axis 15. A central axis (eccentric axis) 38 (see FIG. 7) of the cylindrical inner peripheral surface 37 is parallel to the central axis of the cylindrical outer peripheral surface 36 but is eccentric from the central axis of the cylindrical outer peripheral surface 36. Therefore, the cylindrical inner peripheral surface 37 of the rotor case 35 fixed in the housing 14 and the central axis 38 thereof are decentered downward in FIG. As shown in FIG. 8, the cylindrical inner peripheral surface 37 of the rotor case 35 is formed with enlarged portions 39 and 40 by widening the two base end sides outward in the radial direction. As shown in the drawing, the enlarged portions 39 and 40 are formed on the side opposite to the eccentric direction (near the center or upper portion in FIG. 8).

  With the above configuration, in the state where the rotor 20 is assembled to the housing 14, the outer peripheral end portions 41 (except for the portions facing the enlarged portions 39 and 40) of each blade 33 are removed from the rotor case by the biasing force of the spring 34. The pressurizing chamber 42 is formed between the adjacent blades 33. In the embodiment, five pressurizing chambers 42 partitioned by five blades 33 are formed.

(2-3) Bearing:
As shown in FIGS. 3 to 5, the end-side bearing 23 that supports the end side of the rotor shaft 22 is held by an end-side bearing case (fixing member) 43 that is fixed to the housing 14 adjacent to the rotor 20. Yes. The end-side bearing case 43 is made of an annular or cylindrical member and regulates the end-side end 45 (see FIG. 7) of the blade 33 that is fixed to the housing 14 and moves as the rotor 20 rotates. The end side bearing 23 is accommodated in the inner peripheral cylindrical portion 44. In the embodiment, the end bearing 23 is a ball bearing and is composed of an outer bearing ring, an inner bearing ring, and a plurality of balls disposed between the outer and inner bearing rings. Is fixed to the inner peripheral cylindrical portion 44 of the end side bearing case 43, and the inner bearing ring is fixed to the bearing seat 27.

  As shown in FIG. 14, the proximal end side of the inner peripheral cylindrical portion 44 accommodates the distal side protruding portion 25 of the rotor 20 in a rotatable manner. Therefore, the inner diameter on the proximal end side of the inner peripheral cylindrical portion 44 is slightly larger than the outer diameter of the distal-side protruding portion 25, and a gap (radial gap x) of about 5 to 15 μm or less is formed between the two. Has been. On the other hand, a gap (thrust gap y) is formed between the rotor 20 (that is, the bearing seat 27) and the terminal-side bearing case 43 in the direction of the central axis 15.

  The end side bearing case 43 is also a plurality of members arranged concentrically around the central axis 15 on the end side of the end side bearing case 43, for example, a cylindrical connection guide 46, a cylindrical button sheet 47, Movement to the base end side is regulated by the fixing ring 48. The connection guide 46 and the fixing ring 48 are integrally formed and are fixed to the handpiece body 11. The connection guide 46 and the fixing ring 48 may be configured separately for processing and assembly, or may be detachable from the handpiece body 11.

  As shown in FIGS. 3 to 5, the proximal bearing 24 that supports the distal side of the rotor shaft 22 is a proximal bearing case (second member, fixed) that is fixed to the housing 14 adjacent to the rotor 20. Member) 50. The base end side bearing case 50 is configured by a disk-shaped (or solid cylindrical shape) member, and is formed in a cylindrical recess (bearing accommodating chamber) 52 formed in the end side end surface 51 facing the rotor 20. The base end side bearing 24 is accommodated. In the embodiment, the proximal bearing 24 is a ball bearing and is composed of an outer bearing ring, an inner bearing ring, and a plurality of balls disposed between the outer and inner bearing rings. Is fixed to the base end side bearing case 50, and the inner bearing ring is fixed to the bearing seat 28. A wave washer (wave washer) 49 (see FIG. 8) made of an annular metal plate is disposed at the bottom of the recess 52 on the base end side, and the wave washer 49 restricts the movement of the rotor 20 in the central axis direction. Has been.

  As shown in FIG. 14, the distal end side of the cylindrical recess 52 accommodates the proximal-side protruding portion 26 of the rotor 20 in a rotatable manner. Therefore, as shown in FIG. 3, the inner diameter on the distal end side of the cylindrical recess 52 is slightly larger than the outer diameter of the base end side protruding portion 26, and a gap (radial gap x) is formed between them. ing. Further, a gap (thrust gap y) is formed between the rotor 20 (that is, the bearing seat 28) and the base end side bearing case 50 with respect to the direction of the central axis 15.

  The radial gap x and the thrust gap y formed between the terminal side bearing case 43 and the base end side bearing case 50 and the rotor 20 will be described. The air motor 13 configured by arranging a plurality of components in the central axis direction is as follows. While it is difficult to reduce the gap in the central axis direction (thrust direction) to about 30 μm or less, it is sufficiently possible to set the gap in the radial direction (radial direction) to a smaller value. Therefore, in the embodiment, the radial gap x is set to about 5 to 15 μm or less, thereby minimizing the amount of pressure air leaking from between the distal bearing case 43 and the proximal bearing case 50 and the rotor 20. It is suppressed. In addition, since both sides of the pressurizing chamber 42 are sealed with the radial gap x with respect to the central axis direction, and the thrust gap y is disposed on the outer side thereof, even if the thrust gap y is larger than the radial gap x, the pressure air Substantial leakage is prevented. In other words, increasing the thrust gap y does not affect the leakage of pressurized air. Therefore, high accuracy is not necessary for the assembly in the thrust direction. Furthermore, even if the rotor 20 moves in the thrust direction due to bearing wear or the like, the rotor 20 does not come into contact with adjacent members.

  Three vent passages are formed in the base end side bearing case 50. Specifically, referring to FIG. 9 (a view of the base end side bearing case 50 as viewed from the base end side toward the distal end side), the air passages (second air supply passages) 53, 54, 55 are A proximal-side air passage portion extending in parallel with the central axis 15 from the proximal-side end surface 56 to the vicinity of the recess 52, and a radially outer side from the radially outer position of the recess 52 toward the distal-side end surface 51. It is comprised by the terminal side ventilation path part extended diagonally. The centers of the mouth portions 57, 58, 59 that open to the base end side end face 56 of the three air passages 53, 54, 55 are arranged on a circumference with a predetermined radius r centering on the central axis 15. In the embodiment, the three air passages 53, 54, 55 are not arranged at equal intervals in the circumferential direction. However, the three air passages may be arranged at equal intervals in the circumferential direction.

  Although not shown, in the distal end surface 51 of the proximal end side bearing case 50, the air passages 53, 54 communicate with the enlarged portions 39, 40 formed on the proximal end inner peripheral surface 37 of the rotor case 35. For example, the pressurized air supplied to the rotor 20 through the air passages 53 and 54 is supplied to the pressurizing chamber 42 passing through the inside of the enlarged portions 39 and 40 via the enlarged portions 39 and 40.

(2-4) Valve member:
As shown in FIGS. 3 to 5, a valve member (control valve, first member) 60 is disposed on the base end side of the base end side bearing case 50. The valve member 60 is formed of a substantially disk-shaped member, and is provided inside the housing 14 so as to be rotatable about the central axis 15. As shown in FIGS. 10 and 11, the valve member 60 is formed with an air supply path (first air supply path) 63 and an exhaust path 64 that penetrate the distal end face 61 and the proximal end face 62. In the embodiment, the air supply path 63 includes a proximal end air supply path portion extending from the proximal end face 62 along the central axis 15 to the vicinity of the distal end face 61, and a distal end face 61 parallel to the central axis 15. It is comprised by the terminal side air supply path part extended toward the base end side end surface 62, and the central air supply path part which connects these base end side air supply path parts and terminal side air supply path parts (refer FIG. 3). .

  A mouth portion (outlet) 65 of the distal-side air supply path portion in the distal-side end surface 61 shown in FIG. 11 is from the central shaft 15 in the same manner as the air passages 53, 54, 55 formed in the proximal-side bearing case 50. It is located on the circumference of a predetermined radius r. Further, as shown in FIG. 11, the end surface 61 of the valve member 60 has two annular grooves 66, 67 surrounding the air supply passage outlet 65, and each includes a seal member 68, formed of an O-ring. 69 is fitted. The seal members 68 and 69 protrude from the annular grooves 66 and 67 while being fitted in the annular grooves 66 and 67. Accordingly, in a state where the valve member 60 and the proximal end side bearing case 50 are assembled in the housing 14, the seal members 68 and 69 are connected to the distal end surface 61 of the valve member 60 and the proximal end surface of the proximal end bearing case 50. 56, and seals around the air supply path outlet 65.

  The exhaust passage 64 extends long along the circumference centered on the central axis 15, and as shown in FIG. 11, the distal end face 61 has a mouth ( As shown in FIG. 10, the base end side end face 62 appears as two mouth portions (exhaust outlets) 71 that extend short in the circumferential direction.

  In order for the surgeon to operate the valve member 60, a connection pin 72 is attached to the outer peripheral surface of the valve member 60. As shown in FIG. 12, the connecting pin 72 passes through a through-hole 73 formed in the terminal-side housing portion 16, and its radial end portion is engaged with the adjusting portion 18. The through-hole 73 of the terminal side housing part 16 is formed as a long hole extending in the circumferential direction so that the adjusting part 18 can rotate over a range of about 150 ° in the circumferential direction.

(2-5) Bush:
As shown in FIGS. 3 to 5, a bush 74 is disposed on the proximal end side of the valve member 60. The bush 74 is fixed to the housing 14, and an air supply path 75 and an exhaust path 76 communicating with the air supply path 63 and the exhaust path 64 of the valve member 60 described above are formed. The end portion of the air supply path 75 is formed along the central axis 15 and is always in communication with the air supply path 63 of the valve member 60. On the other hand, the end portion of the exhaust passage 76 is formed at a position eccentric from the central shaft 15 and is always in communication with the exhaust passage 64 of the valve member 60.

[B: Operation]
The operation of the handpiece 10 and the air motor 13 having the above configuration will be described. When the cutting tool 12 is rotated forward, the surgeon operates the adjusting portion 18 if necessary, and the air supply passage port portion (exit) 65 of the valve member 60 is provided with the air passage 53 provided in the proximal end side bearing case 50. Opposite to the mouth (inlet) 57. FIG. 13 shows the relationship between the base end side end surface 56 of the base end side bearing case 50, the air supply passage port (outlet) 65 of the valve member 60 facing it, and the seal members 68 and 69 surrounding the port 65. In particular, during forward rotation, as shown in FIG. 13A, only the region 80 surrounded by the inner seal member 68 is opposed to the mouth portion 57 of the air passage 53, and the inner seal member 68 and the outer seal A region 81 between the members 69 does not face any air passage.

  Therefore, the pressure air supplied from the pressure air supply source (not shown) is supplied from the air supply passage 75 of the bush 74, the air supply passage 63 of the valve member 60, the air passage 53 of the base end side bearing case 50, and the rotor case. It is supplied to the pressurizing chamber 42 opened toward the enlarged portion 39 through the enlarged portion 39 of 35. The pressurizing chamber 42 facing the enlarged portion 39 is located on the side opposite to the eccentric direction. Therefore, the rotor 20 rotates in the forward rotation direction due to the pressure difference in the circumferential direction acting on the two adjacent blades 33 forming the pressurizing chamber 42 facing the enlarged portion 39. Then, the rotation of the rotor 20 is transmitted to the cutting tool 12 via the shaft 22 and a rotation connecting member (not shown).

  The pressurized air in the pressurizing chamber 42 moves in the forward direction along with the rotation of the rotor 20, and from the other vent path 55 of the base end side bearing case 50 to the exhaust path 64 of the valve member 60 and the exhaust path 76 of the bush 74. And discharged to the base end side.

  When reducing the rotation speed of the cutting tool that normally rotates, the surgeon rotates the adjustment unit 18 in the direction of the arrow 83. As a result, as shown in FIG. 13 (b), the facing area (communication area) between the air supply passage port (outlet) 65 of the valve member 60 and the mouth 57 of the vent passage 53 of the end side bearing case 43 is reduced. The amount of pressurized air supplied to the rotor 20 is reduced. As a result, the rotational force applied to the rotor 20 decreases, and the rotational speed and rotational torque of the rotor 20 decrease. At this time, the mouth portion 57 of the vent path 53 of the end side bearing case 43 is inside the region 81 surrounded by the outer seal member 69. Therefore, the compressed air contributes to the rotation of the rotor 20 without leaking into the gap between the valve member 60 and the base end side bearing case 50. Further, since the pressure air corresponding to the rotation amount of the adjusting unit 18 is supplied to the rotor 20, the adjustment of the rotation speed and the torque is stabilized.

  When stopping the rotation of the rotor 20, as shown in FIGS. 13B and 13C, the operator rotates the adjustment unit 18 in the direction of the arrow 83. Accordingly, as shown in FIG. 13C, the air supply passage port (outlet) 65 of the valve member 60 does not face the port 57 of the vent passage 53 of the terminal side bearing case 43, and the pressure air to the rotor 20 The supply amount of is stopped. As shown in the drawing, at this time, the mouth portion 57 of the air passage 53 of the end side bearing case 43 is outside the region 80 surrounded by the inner seal member 68, and the inner seal member 68 and the outer seal member 69. It is inside the area 81 between. Therefore, the pressure air in the air supply passage port 65 located inside the inner seal member 68 does not leak into the gap on the opposing surface of the valve member 60 and the base end side bearing case 50.

  On the other hand, when the rotor 20 is rotated in the reverse direction, although not shown, the adjusting portion 18 is rotated in the direction of the arrow 84 in FIG. 13, and the mouth portion 65 of the air supply passage 63 of the valve member 60 is connected to the ventilation passage 54 of the proximal end side bearing case 50. To face. As a result, the supplied pressurized air is supplied from the air supply path 63 of the valve member 60 and the ventilation path 54 of the end side bearing case 43 to the pressurizing chamber 42 facing the enlarged portion 40 through the enlarged portion 40, and the arrow 84. Rotate the rotor 20 in the direction. The rotation of the rotor 20 is transmitted to the cutting tool 12 through the shaft 22 and the like.

  The pressurized air in the pressurizing chamber 42 moves in the reverse direction along with the rotation of the rotor 20, and from the other vent passage 55 of the base end side bearing case 50 through the exhaust passage 66 of the valve member 60 and the exhaust passage 76 of the bush 74. And discharged to the base end side.

  Similarly to the forward rotation, the rotational speed and torque of the rotor 20 can be adjusted by operating the adjusting unit 18 even during the reverse rotation. Although the explanation using the drawings is omitted, by appropriately determining the position of the outer seal member 69, it is possible to prevent the pressure air from leaking from the gap between the valve member 60 and the end side bearing case 43, and according to the adjustment amount. Stable rotation speed and torque can be obtained.

  In the above description, the seal members 68 and 69 are formed by O-rings, but they can also be formed by an adhesive (for example, a silicon adhesive).

  In the above description, the protrusions 25 and 26 of the rotor 20 are formed integrally with the rotor main body 21. However, the protrusions 25 and 26 may be formed of separate members and fixed to the rotor main body 21. . In this case, in order to prevent the pressure air from leaking through the contact portion of the protruding portion of the separate member and the rotor 21, it is preferable to interpose a sealing material or an adhesive between them.

DESCRIPTION OF SYMBOLS 10 Handpiece 11 Handpiece main body 12 Cutting tool 13 Air motor 14 Housing (housing)
15 central axis (first central axis)
16 Terminal-side housing part 17 Base-side housing part 18 Adjustment part 20 Rotor 21 Rotor body 22 Shaft 23 Terminal-side bearing 24 Base-side bearing 25 Terminal-side protruding part 26 Base-side protruding part 27 Terminal-side bearing sheet 28 Base-side side Bearing seat 29 Cylindrical outer peripheral surface 30 End side end surface 31 Base end side end surface 32 Radiation groove 33 Blade (vane)
34 Spring 35 Rotor case 36 Cylindrical outer peripheral surface 37 Cylindrical inner peripheral surface 38 Central axis (second central axis, eccentric shaft)
39, 40 Enlarged portion 41 Blade outer peripheral end 42 Pressurizing chamber 43 Terminal side bearing case 44 Inner peripheral cylindrical portion 45 Blade distal end surface 46 Connection guide 47 Button seat 48 Fixing ring 50 Base end bearing case 51 Terminal end surface 52 recess (bearing accommodation chamber)
53, 54, 55 Ventilation path 56 Base end side end face 57, 58, 59 Port 60 Valve member (regulating valve)
61 End side end face 62 Base end side end face 63 Air supply path 64 Air exhaust path 65 Air supply path port (exit)
66, 67 annular groove 68, 69 seal member 70 mouth (exhaust inlet)
71 mouth (exhaust outlet)
72 connecting pin 73 through hole 74 bush 75 air supply path 76 exhaust path 80 area surrounded by inner seal member 81 area surrounded by outer seal member

Claims (4)

In a housing having a central axis,
A rotor provided with a shaft rotatably supported around the central axis and a rotor body fixed to the shaft;
A rotor case that is externally mounted on the rotor body and includes an inner peripheral surface that is parallel to the central axis and that is centered on an eccentric shaft that is separated from the central axis;
The rotor body is a plurality of vanes attached to the rotor, and is arranged at predetermined intervals in the circumferential direction around the central axis, and is capable of moving forward and backward in the radial direction around the central axis. Further, it is supported by the rotor body in a state of being urged radially outward and in contact with the inner peripheral surface of the rotor case, and moves in the circumferential direction of the central axis as the rotor body rotates. While moving in the radial direction, and has a plurality of vanes that form a space between each adjacent vane,
An air motor that rotates the rotor based on a difference in circumferential pressure received by two adjacent vanes when pressurized fluid is supplied to the space,
The air motor is
A proximal end and a distal side fixing member disposed on the proximal end side and the distal end side of the rotor main body with respect to the direction of the central axis and respectively fixed to the housing;
The proximal and distal sides of the rotor body are adjacent to the rotor body and between the rotor body and the fixing member, respectively, and block the pressure fluid leaking from the proximal and distal sides of the plurality of vanes. A proximal end side and a distal side bearing sheet,
With respect to the thrust direction parallel to the central axis, a thrust gap is formed between the thrust direction end surface portions on the base end side and the distal end side of the bearing seat and the thrust direction end surface portion of the fixing member facing the thrust direction end surface portion. Is formed,
With respect to the radial direction away from the central axis, a radial gap is formed between the radial direction outer peripheral portion on the proximal end side and the distal end side of the bearing seat and the radial direction end surface portion of the fixing member facing the radial direction outer peripheral portion. Formed,
The air motor according to claim 1, wherein the radial gap is smaller than the thrust gap.   A medical handpiece comprising a mechanism for transmitting the rotation of the rotor in the air motor according to claim 1 to a rotating component that is detachably and rotatably mounted on the housing.   The radial gap and the thrust gap are disposed on the proximal end side of the radial gap on the proximal end side of the rotor body with respect to the space between the adjacent vanes. The air motor according to claim 1, wherein the thrust gap is disposed on a terminal side of the radial gap.   The radial gap and the thrust gap are disposed on the proximal end side of the radial gap on the proximal end side of the rotor body with respect to the space between the adjacent vanes. Then, the said thrust gap is arrange | positioned at the terminal end side of the said radial gap, The medical handpiece of Claim 2 characterized by the above-mentioned.

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