WO2019163670A1

WO2019163670A1 - Transmission device

Info

Publication number: WO2019163670A1
Application number: PCT/JP2019/005582
Authority: WO
Inventors: 貴光冨山; 禎実廣橋; 潤一井口; 貴之川上; 敬史押田; 雄一水谷; 奨悟佐藤; 将大青山; 秀生斉藤; 孝太郎櫛田
Original assignee: Thk株式会社
Priority date: 2018-02-20
Filing date: 2019-02-15
Publication date: 2019-08-29
Also published as: JPWO2019163670A1; TW201937078A

Abstract

A transmission device (1) is provided with: a first crown gear (21); a second crown gear (22); a third crown gear (23) having opposing teeth that oppose the first crown gear (21) and opposing teeth that oppose the second crown gear (22); and a cam unit (30) that tilts the third crown gear (23) relative to the first crown gear (21) and the second crown gear (22) such that the third crown gear (23) meshes with the first crown gear (21) and the third crown gear (23) meshes with the second crown gear (22), and that causes the third crown gear (23) to undergo a wave motion such that a meshing location moves in the circumferential direction. One of the first crown gear (21) and the second crown gear (22) has a plurality of speed-change gears (21A, 21B) that are partitioned in the radial direction and that have different tooth counts, and has a switching mechanism (40) that switches the speed-change gear to be fixed, from among the plurality of speed-change gears (21A, 21B).

Description

Transmission

The present invention relates to a transmission.
This application claims priority based on Japanese Patent Application No. 2018-027758 filed in Japan on February 20, 2018, the contents of which are incorporated herein by reference.

Patent Document 1 discloses a reduction gear including a first crown gear, a second crown gear, and a third crown gear. The third crown gear is inclined between the first crown gear and the second crown gear so that the third crown gear meshes with the first crown gear and the third crown gear meshes with the second crown gear. Be placed. The third crown gear is rotatably supported by an input shaft having a bent portion. The input shaft causes the third crown gear to make a wave motion so that the meshing position of the first crown gear and the third crown gear and the meshing position of the third crown gear and the second crown gear move in the circumferential direction.

¡The first crown gear is fixed to the housing, and the second crown gear is connected to the output shaft. When the input shaft is rotated, the third crown gear rotates relative to the first crown gear by the difference in the number of teeth of the third crown gear due to the wave motion of the third crown gear. Further, due to the wave motion of the third crown gear, the second crown gear rotates relative to the third crown gear by the difference in the number of teeth. The rotational speed of the second crown gear is the sum of the relative rotational speed of the third crown gear with respect to the first crown gear and the relative rotational speed of the second crown gear with respect to the third crown gear. If the two sets of gears (the first crown gear and the third crown gear, the third crown gear and the second crown gear) are rotated in directions that cancel each other, a large reduction ratio can be obtained, and in a direction that promotes each other. If it is rotated, a small reduction ratio can be obtained.

JP 60-4647 A

By the way, the speed reducer has a compact device configuration in the radial direction as compared with a normal speed reducer such as a spur gear, and is expected to be introduced into a joint portion of an industrial robot. Various movements are required for industrial robots. For example, when lifting a transported object, it is preferable to move it at a low speed and with a large torque. Also, after placing the transported object, the next transported object is picked up. When going, it is preferable to move at high speed with a small torque. However, since the reduction gear ratio switching technology that meets such a demand has not been established in the above reduction gear, it has been one of the problems in practical use.

The present invention provides a transmission that is compact and capable of switching the reduction ratio.

According to the first aspect of the present invention, the transmission includes a first crown gear, a second crown gear, an opposing tooth facing the first crown gear, and an opposing tooth facing the second crown gear. The third crown gear has the first crown, and the third crown gear meshes with the first crown gear, and the third crown gear meshes with the second crown gear. A cam portion that wave-moves the third crown gear so that the meshing portion is inclined with respect to the gear and the second crown gear and moves in a circumferential direction, and the first crown gear and the second crown gear One of the crown gears has a plurality of transmission gears with different numbers of teeth divided in the radial direction, and has a switching mechanism that switches among the plurality of transmission gears to be fixed.

¡According to the transmission described above, the reduction gear ratio can be switched in a compact manner.

It is a perspective view of the transmission in the first embodiment of the present invention. It is a longitudinal cross-sectional view of the transmission in 1st embodiment of this invention. It is an enlarged view of the principal part containing the 1st crown gear, the 2nd crown gear, and the 3rd crown gear in a first embodiment of the present invention. It is a perspective view of the 1st crown gear in a first embodiment of the present invention. It is a front view of the 1st crown gear, the 2nd crown gear, and the 3rd crown gear in a first embodiment of the present invention. It is explanatory drawing explaining the coarse movement of the transmission in 1st embodiment of this invention. It is explanatory drawing explaining the fine movement of the transmission in 1st embodiment of this invention. It is a longitudinal cross-sectional view of the transmission in 2nd embodiment of this invention. It is explanatory drawing explaining the coarse movement of the transmission in 2nd embodiment of this invention. It is explanatory drawing explaining the fine movement of the transmission in 2nd embodiment of this invention. It is a longitudinal cross-sectional view of the transmission in 3rd embodiment of this invention. It is a longitudinal cross-sectional view of the transmission in 4th embodiment of this invention.

Hereinafter, a transmission according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a perspective view of a transmission 1 according to a first embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the transmission 1 according to the first embodiment of the present invention.
As shown in FIG. 1, the transmission 1 includes a bottomed cylindrical housing 10, and a motor 2 is attached to the bottom of the housing 10. As shown in FIG. 2, the center axis of the bottomed cylindrical housing 10 coincides with the axis L of the rotating shaft 2 a of the motor 2. Hereinafter, a direction in which the axis L extends is referred to as an axial direction, a direction orthogonal to the axis L is referred to as a radial direction, and a direction around the axis L is referred to as a circumferential direction.

As shown in FIG. 2, a first crown gear 21, a second crown gear 22, a third crown gear 23, a cam portion 30, and a switching mechanism 40 described later are housed inside the housing 10. The rotating shaft 2a of the motor 2 is connected to the cam portion 30 via a shaft joint 39, and the cam portion 30 supports the third crown gear 23 in an inclined manner. When the cam portion 30 rotates, the third crown gear 23 that meshes with the first crown gear 21 performs a wave motion (this wave motion is also referred to as precession motion), and the rotational speed of the rotating shaft 2a is decelerated to reduce the second crown. The gear 22 (output gear) rotates. The reduction ratio is determined by the number of teeth of the first crown gear 21, the second crown gear 22, and the third crown gear 23 (described later).

The housing 10 includes a mounting plate 11, a first cylindrical portion 12, a second cylindrical portion 13, and a presser plate 14. The motor 2 is attached to the attachment plate 11 via bolts 3. The mounting plate 11 is a disk member that forms the bottom of the housing 10, and the rotation shaft 2 a of the motor 2 is inserted through the center of the mounting plate 11. The first cylindrical portion 12 is connected to the surface of the mounting plate 11 opposite to the mounting surface of the motor 2 via a bolt (not shown). A switching mechanism 40 described later is accommodated inside the first cylindrical portion 12.

The second cylindrical portion 13 is connected to the first cylindrical portion 12 via a bolt 17 in the axial direction. A step is formed on the inner peripheral side of the connecting portion between the first cylindrical portion 12 and the second cylindrical portion 13 to support the bearing 15. The bearing 15 supports a second transmission gear 21B (described later) of the first crown gear 21 so as to be rotatable around the axis L. A first crown gear 21, a second crown gear 22, a third crown gear 23, and a cam portion 30 are accommodated inside the second cylindrical portion 13.

The pressing plate 14 is an annular plate and is connected to the upper end surface of the second cylindrical portion 13 via a bolt 18. A step is formed on the inner peripheral side of the connecting portion between the second cylindrical portion 13 and the presser plate 14 to support the bearing 16. The bearing 16 supports the second crown gear 22 so as to be rotatable around the axis L. The upper end surface of the second crown gear 22 protrudes outward in the axial direction from the presser plate 14, and an attachment hole 22b for attaching an object to be rotated is formed on the upper end surface.

FIG. 3 is an enlarged view of a main part including the first crown gear 21, the second crown gear 22, and the third crown gear 23 in the first embodiment of the present invention. FIG. 4 is a perspective view of the first crown gear 21 in the first embodiment of the present invention. FIG. 5 is a front view of the first crown gear 21, the second crown gear 22, and the third crown gear 23 in the first embodiment of the present invention.
As shown in FIG. 3, an annular first crown gear 21 and an annular second crown gear 22 are disposed coaxially with the axis L inside the housing 10. A third crown gear 23 is arranged between the first crown gear 21 and the second crown gear 22.

The first crown gear 21 has opposing

teeth

21 a and 21 b on the side facing the third crown gear 23. The second crown gear 22 has opposing teeth 22 a on the side facing the third crown gear 23. The third crown gear 23 has opposing teeth 23a facing the first crown gear 21 and opposing teeth 23b facing the second crown gear 22 in back-to-back alignment. The third crown gear 23 is inclined by an angle α with respect to a plane orthogonal to the axis L. By tilting the third crown gear 23, as shown in FIG. 5, the counter tooth 23a of the third crown gear 23 meshes with the first crown gear 21 at one place in the circumferential direction, and the counter tooth 23b is The second crown gear 22 meshes at one place in the circumferential direction.

As shown in FIG. 3, the third crown gear 23 is supported by the cam portion 30. The cam portion 30 includes a first cam 31 that extends to the first crown gear 21 side relative to the third crown gear 23, and a second cam 32 that extends to the second crown gear 22 side relative to the third crown gear 23. . A bearing 35 that supports a first transmission gear 21 A (described later) of the first crown gear 21 is disposed on the outer peripheral side of the first cam 31. A bearing 36 that supports the second crown gear 22 is disposed on the outer peripheral side of the second cam 32.
The first cam 31 and the second cam 32 are connected in the axial direction via a bolt 34.

The third crown gear 23 is disposed at the connection portion between the first cam 31 and the second cam 32. Specifically, a first inclined surface 31 a and a second inclined surface 32 a that are parallel to each other and inclined with respect to the axis L are formed on the outer peripheral side of the connecting portion between the first cam 31 and the second cam 32. . Similar to the third crown gear 23, the first inclined surface 31 a and the second inclined surface 32 a are inclined by an angle α with respect to a plane orthogonal to the axis L.

Between the first cam 31 and the third crown gear 23, a rolling element 33 (ball or the like) is interposed. In the first inclined surface 31a, a rolling element rolling groove 31b having a substantially circular cross-sectional view in which the rolling element 33 rolls is formed. Also in the third crown gear 23, a rolling element rolling groove 23c having a substantially circular cross-sectional view is formed at a location facing the rolling element rolling groove 31b. The rolling

element rolling grooves

23c and 31b are formed in an annular shape around the axis L, and a plurality of rolling elements 33 are arranged so as to be capable of infinite circulation.

Also, a rolling element 33 (ball or the like) is interposed between the second cam 32 and the third crown gear 23. In the second inclined surface 32a, a rolling element rolling groove 32b having a substantially circular cross-sectional view in which the rolling element 33 rolls is formed. The third crown gear 23 is also formed with a rolling element rolling groove 23d having a substantially circular cross-sectional view at a location facing the rolling element rolling groove 32b. The rolling

element rolling grooves

23d and 32b are formed in an annular shape around the axis L, and a plurality of rolling elements 33 are arranged so as to be capable of infinite circulation.

Note that the rolling element 33 may be held by a retainer for preventing dropout (not shown). Further, it is preferable to apply a preload to the rolling elements 33 so that backlash does not occur in the third crown gear 23 sandwiched between the first cam 31 and the second cam 32. For example, the first cam 31 and the second cam 32 are tightened in the axial direction by the bolt 34, whereby the rolling element 33 is pressurized between the rolling

element rolling grooves

23c and 31b and between the rolling

element rolling grooves

23d and 32b. Can be given.

2, a shaft coupling portion 37 is connected to the second cam 32 via a bolt 38 on the side opposite to the first cam 31. The connecting portion between the second cam 32 and the shaft coupling portion 37 is formed with a step on the outer peripheral side, and supports the bearing 35 described above. The shaft connecting portion 37 has a connecting shaft 37 a extending along the axis L, and the connecting shaft 37 a is connected to the rotating shaft 2 a of the motor 2 through a shaft joint 39.

3 and 4, the first crown gear 21 has a first transmission gear 21A and a second transmission gear 21B that are divided in the radial direction. The first transmission gear 21A and the second transmission gear 21B are each formed in an annular shape and are arranged coaxially with the axis L. In the present embodiment, the first transmission gear 21A is disposed on the radially inner side of the second transmission gear 21B. The first transmission gear 21 A has opposing teeth 21 a on the side facing the third crown gear 23. Further, the second transmission gear 21B has opposed teeth 21b having a different number of teeth from the opposed teeth 21a on the side facing the third crown gear 23.

2, the first transmission gear 21A and the second transmission gear 21B are supported by the switching mechanism 40. The switching mechanism 40 fixes one of the first transmission gear 21 A and the second transmission gear 21 B to the housing 10 according to the rotation direction. Specifically, the switching mechanism 40 includes a first one-way clutch 41 that rotates the first transmission gear 21A only in one direction (for example, clockwise around the axis L), and a second transmission gear 21B that is the first transmission gear 21A. And a second one-way clutch 42 that rotates only in one direction (for example, counterclockwise about the axis L).

For example, when rotating clockwise about the axis L, the first transmission gear 21A can be freely rotated in that direction by the first one-way clutch 41, while the second transmission gear 21B is The rotation in that direction is restricted by the two one-way clutch 42 and is fixed (stopped) with respect to the housing 10. For example, when rotating counterclockwise around the axis L, the second transmission gear 21B can be freely rotated in that direction by the second one-way clutch 42, while the first transmission gear 21A. The first one-way clutch 41 restricts rotation in that direction and is fixed (stopped) to the housing 10.

The first one-way clutch 41 and the second one-way clutch 42 are supported by sandwiching a spacer 44 on the outer peripheral surface of a cylindrical support member 43 connected to the mounting plate 11 via a bolt (not shown). The cylindrical support member 43 is formed with a through hole 43a in which the rotating shaft 2a, the connecting shaft 37a, and the shaft coupling 39 are disposed. Further, a flange portion 43 b that supports the second one-way clutch 42 extends radially outward on the mounting plate 11 side of the cylindrical support member 43. A presser plate 45 that sandwiches the first one-way clutch 41, the spacer 44, and the second one-way clutch 42 in the axial direction is connected to the upper end surface of the cylindrical support member 43 through bolts 46. Yes.

The first one-way clutch 41 is connected to the first transmission gear 21 A via the first connection member 47. The first connecting member 47 is a stepped cylindrical member whose upper end is reduced in diameter, and the reduced upper end is connected to the bottom of the first transmission gear 21 A via a bolt 48. A step is formed on the inner peripheral side of the connecting portion between the first transmission gear 21 A and the first connecting member 47, and supports the bearing 35 described above.

The second one-way clutch 42 is connected to the second transmission gear 21 B via the second connection member 49. The second connecting member 49 includes a bottomed cylindrical first member 49A having an inner diameter larger than the outer diameter of the first connecting member 47, and a second member connected to the upper end of the first member 49A via a bolt 50. 49B.

The second member 49B is a stepped cylindrical member whose upper end portion is reduced in diameter. The inner diameter of the reduced upper end portion is larger than the outer diameter of the reduced upper end portion of the first connection member 47, and It is smaller than the outer diameter of the lower end portion of the one connecting member 47 that is not reduced in diameter. The upper end portion of the second member 49B is connected to the bottom portion of the second transmission gear 21B via a bolt 51. A step is formed on the outer peripheral side of the connecting portion between the second transmission gear 21B and the second connecting member 49 (second member 49B), and supports the bearing 15 described above.

According to the transmission 1 having the above configuration, when the rotation shaft 2a of the motor 2 is rotated, the third crown gear 23 sandwiched between the first cam 31 and the second cam 32 performs a wave motion (that is, the third crown gear 23). Will precess). Along with the wave motion of the third crown gear 23, the meshing position of the first crown gear 21 and the third crown gear 23 and the meshing position of the third crown gear 23 and the second crown gear 22 move in the circumferential direction. To do. The meshing location of the first crown gear 21 and the third crown gear 23 and the meshing location of the third crown gear 23 and the second crown gear 22 are point-symmetrical positional relations about the axis L as viewed from the axial direction. When the meshing portion moves in the circumferential direction, the third crown gear 23 swings left and right like a seesaw in the cross-sectional view shown in FIG.

With such wave motion of the third crown gear 23, the third crown gear 23 rotates around the axis L relative to the first crown gear 21 by the difference in the number of teeth of both. Further, the second crown gear 22 rotates about the axis L relative to the third crown gear 23 by the difference in the number of teeth of both. The rotational speed of the second crown gear 22 is the sum of the relative rotational speed of the third crown gear 23 with respect to the first crown gear 21 and the relative rotational speed of the second crown gear 22 with respect to the third crown gear 23. Become a thing. If the two sets of gears (the first crown gear 21 and the third crown gear 23, the third crown gear 23 and the second crown gear 22) are rotated in a direction that cancels each other, a large reduction ratio can be obtained. A small reduction ratio can be obtained by rotating in the promoting direction.

Z _{1 is} the number of teeth of the opposing teeth 21 a to 21 b of the first crown gear 21, Z _{2 is} the number of teeth of the opposing teeth 23 a of the third crown gear 23 that meshes with the first crown gear 21, and meshes with the second crown gear 22. If the number of teeth of the counter teeth 23b of the third crown gear 23 is Z ₃ and the number of teeth of the counter teeth 22a of the second crown gear 22 is Z ₄ , the reduction ratio GR is given by the following equation (1).

For example, if Z ₁ = 40, Z ₂ = 40, Z ₃ = 43, and Z ₄ = 42, the reduction ratio GR is -1/42. On the other hand, if the number of teeth of Z ₁ is reduced by one and Z ₁ = 39, Z ₂ = 40, Z ₃ = 43, and Z ₄ = 42, the reduction ratio GR is 1/560. As described above, when Z ₁ = Z ₂ , the first crown gear 21 serves only to stop the rotation of the third crown gear 23, and the reduction ratio is left to the second crown gear 22. Such movement is called coarse movement. If Z ₁ ≠ Z ₂ , the first crown gear 21 also has a role of reduction, and the reduction ratio is left to the first crown gear 21 and the second crown gear 22 to obtain a large reduction ratio. Such movement is called fine movement. In the present embodiment, the first transmission gear 21A has the number of teeth of Z ₁ = 39 in the above example, and the second transmission gear 21B has the number of teeth of Z ₁ = 40.

FIG. 6 is an explanatory diagram for explaining coarse movement of the transmission 1 according to the first embodiment of the present invention.
As shown in FIG. 6, when the transmission 1 coarsely moves, the first transmission gear 21A is rotatable clockwise around the axis L by the first one-way clutch 41 (see FIG. 2), The transmission gear 21B is fixed (does not rotate) by the second one-way clutch 42 (see FIG. 2). At this time, the first transmission gear 21 A only rotates with the third crown gear 23 and has no special role. Therefore, in FIG. 6, it is expressed in white.

On the other hand, the fixed second transmission gear 21B meshes with the third crown gear 23, thereby contributing to the wave motion of the third crown gear 23. Therefore, in FIG. 6, it is expressed with dots. The second transmission gear 21 B has opposing teeth 21 b having the same number of teeth (Z ₁ = Z ₂ ) as the opposing teeth 23 a of the third crown gear 23. The third crown gear 23 rotates around the axis L relative to the second transmission gear 21B by the difference in the number of teeth with the wave motion. Does wave motion but does not rotate. In this way, the second transmission gear 21B serves only to stop the rotation of the third crown gear 23, and the reduction ratio is left to the second crown gear 22, so the reduction ratio becomes small and the second crown gear 22 Coarse rotation at high speed and low torque.

FIG. 7 is an explanatory diagram illustrating fine movement of the transmission 1 according to the first embodiment of the present invention.
As shown in FIG. 7, when the transmission 1 is finely moved, the second transmission gear 21B can be rotated counterclockwise about the axis L by the second one-way clutch 42 (see FIG. 2). The transmission gear 21A is fixed (does not rotate) by the first one-way clutch 41 (see FIG. 2). At this time, the second transmission gear 21 B only rotates with the third crown gear 23 and has no special role. Therefore, in FIG. 7, it is expressed in white.

On the other hand, the fixed first transmission gear 21 A meshes with the third crown gear 23, thereby contributing to the wave motion of the third crown gear 23. Therefore, in FIG. 7, it is expressed with dots. The first transmission gear 21 </ _b > A has opposed teeth 21 a having a different number of teeth (Z ₁ ≠ Z ₂ ) from the opposed teeth 23 a of the third crown gear 23. The third crown gear 23 rotates around the axis L by the difference in the number of teeth with respect to the second transmission gear 21B along with the wave motion, so that the third crown gear 23 rotates while rotating. To do. Thus, the first transmission gear 21A has the role of stopping and reducing the rotation of the third crown gear 23, and the reduction ratio is entrusted to the first transmission gear 21A and the second crown gear 22, so the reduction ratio becomes large. The second crown gear 22 rotates finely at a low speed and with a high torque.

Thus, according to this embodiment mentioned above, the 1st crown gear 21, the 2nd crown gear 22, the opposing tooth 23a which opposes the 1st crown gear 21, and the opposing tooth 23b which opposes the 2nd crown gear 22 And the third crown gear 23 mesh with the first crown gear 21, and the third crown gear 23 meshes with the second crown gear 22. A cam portion 30 that is inclined with respect to the first crown gear 21 and the second crown gear 22 and that causes the third crown gear 23 to perform a wave motion so that the meshing portion moves in the circumferential direction. And the second crown gear 22 has a plurality of transmission gears 21A and 21B with different numbers of teeth divided in the radial direction, and a switch for switching a transmission gear to be fixed among the plurality of transmission gears 21A and 21B. Adopting a structure having a mechanism 40 Therefore, it is possible to switch the reduction ratio while maintaining a compact device configuration in the radial direction.

Further, since the switching mechanism 40 of the present embodiment switches the transmission gears 21A and 21B to be fixed according to the rotation direction, for example, the reduction ratio is determined between the direction of the operation of the industrial robot and the return (forward and reverse rotation of the motor 2). Can be changed. For example, when an industrial robot winds up a rope via the transmission 1 to lift a conveyed product, it can be finely moved at a low speed and with a high torque. When picking up a conveyed product, it can be coarsely moved at a high speed and with a low torque, so that the work efficiency of the industrial robot can be increased and the productivity can be improved.

In the present embodiment, the switching mechanism 40 includes the first one-way clutch 41 that rotates the first transmission gear 21A in only one direction, and the second transmission gear 21B in only one direction opposite to the first transmission gear 21A. Since the second one-way clutch 42 is rotated, the reduction ratio can be switched without a power source without using an electric actuator or the like.

Further, as in the present embodiment, if the second transmission gear 21B includes the counter teeth 21b having the same number of teeth as the counter teeth 23a of the third crown gear 23, the rotation of the third crown gear 23 can be fixed and the speed reduction can be achieved. Since the ratio can be left to the second crown gear 22, a small reduction ratio can be easily obtained.

(Second embodiment)
Next, a second embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

FIG. 8 is a longitudinal sectional view of the transmission 1A according to the second embodiment of the present invention.
The transmission 1A according to the second embodiment includes a wedge portion 41A inserted in a gap between the first transmission gear 21A and the second transmission gear 21B, and the wedge portion 41A that fixes the first transmission gear 21A. A switching mechanism 40A having a movable portion 42A movable between a position and a second fixed position for fixing the second transmission gear 21B is provided.

The wedge portion 41A is a cylindrical member that is inserted into an annular gap between the first transmission gear 21A and the second transmission gear 21B, and an inclined portion 43A having an enlarged diameter is formed at the insertion end. An inclined surface 21a1 (tapered surface) that is inclined with respect to the axis L is formed on the outer peripheral surface of the first transmission gear 21A of the second embodiment, similarly to the inclined portion 43A. In addition, an inclined surface 21b1 (tapered surface) inclined with respect to the axis L is formed on the inner peripheral surface of the second transmission gear 21B as well as the inclined portion 43A.

The wedge part 41A is movable in the axial direction by the movable part 42A. The movable part 42A is, for example, an actuator fixed to the housing 10 (not shown in FIG. 8), and can move the output shaft connected to the wedge part 41A in the axial direction. The movable portion 42A includes a wedge portion 41A, a first fixed position P1 (indicated by a two-dot chain line in FIG. 8) for fixing the first transmission gear 21A, and a second fixed position P2 (see FIG. 8) for fixing the second transmission gear 21B. 8 (shown by a solid line).

FIG. 9 is an explanatory diagram for explaining coarse movement of the transmission 1 according to the second embodiment of the present invention.
As shown in FIG. 9, when the transmission 1 is coarsely moved, the movable portion 42A moves the wedge portion 41A to the second fixed position P2. When the wedge portion 41A moves to the second fixed position P2, the inclined portion 43A and the inclined surface 21b1 of the second transmission gear 21B come into contact with each other, and the second transmission gear 21B is fixed, while the first transmission gear 21A is rotatable. It becomes. The fixed second transmission gear 21B meshes with the third crown gear 23 and contributes to the wave motion of the third crown gear 23. However, since there is no difference in the number of teeth, the reduction ratio is small as described above. The double crown gear 22 rotates roughly at high speed and low torque.

FIG. 10 is an explanatory diagram for explaining fine movement of the transmission 1 according to the second embodiment of the present invention.
As shown in FIG. 10, when the transmission 1 is finely moved, the movable portion 42A moves the wedge portion 41A to the first fixed position P1. When the wedge portion 41A moves to the first fixed position P1, the inclined portion 43A and the inclined surface 21a1 of the first transmission gear 21A come into contact with each other, the first transmission gear 21A is fixed, while the second transmission gear 21B is rotatable. It becomes. The fixed first transmission gear 21A meshes with the third crown gear 23, thereby contributing to the wave motion and rotation of the third crown gear 23. As described above, the reduction ratio is large, and the second crown gear 22 is slow. And it rotates finely with high torque.

According to the second embodiment described above, in addition to the same effects as the first embodiment, the reduction ratio can be switched without switching the rotation direction. Further, since the wedge portion 41A inserted in the gap between the first transmission gear 21A and the second transmission gear 21B can be moved and the transmission gears 21A and 21B to be fixed can be switched, the first transmission gear 21A and the second transmission gear 21A can be switched. The number of parts can be reduced and the apparatus configuration can be made more compact than providing a fixing / unlocking mechanism for each 21B.

Further, in the present embodiment, the wedge portion 41A has the inclined portion 43A that can be brought into contact with the first transmission gear 21A and the second transmission gear 21B by moving in the axial direction, and is fixed only by movement in one axial direction. The transmission gears 21A and 21B to be switched can be easily switched.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

FIG. 11 is a longitudinal sectional view of the transmission 1B according to the third embodiment of the present invention.
The transmission 1 B according to the third embodiment includes a motor 2 B that rotates the cam portion 30 inside the cam portion 30 in the radial direction.

The motor 2B is an outer rotor type motor. The motor 2B includes a stator 100 provided with a plurality of coils 102, and an outer rotor 110 provided with a plurality of permanent magnets 111. The coil 102 can be provided on the outer rotor 110 and the permanent magnet 111 can be provided on the stator 100.

The stator 100 has a stator core 101 and a coil 102 supported by the stator core 101. The stator core 101 is formed in a cylindrical shape extending along the axis L. On the circumferential surface of the stator core 101, a plurality of teeth 101a (saliency poles) extending outward in the radial direction are formed. A coil 102 is wound around the teeth 101a.

The lower end portion 101 b of the stator core 101 is fixed to the top portion of the columnar support member 43 B integrated with the mounting plate 11 of the housing 10. The columnar support member 43 B extends upward along the axis L from the center portion of the upper surface of the mounting plate 11. The columnar support member 43B is the solid cylindrical support member 43 (see FIG. 2) described above, and the other configuration is the same as that of the cylindrical support member 43.

The outer rotor 110 has a permanent magnet 111 and a rotor core 112 that supports the permanent magnet 111. The permanent magnet 111 is opposed to the teeth 101a of the stator core 101 with a gap in the radial direction. The permanent magnet 111 is fixed to the inner peripheral surface of a through hole 112a that penetrates the center of the rotor core 112 in the axial direction.

The rotor core 112 is integrated with the cam portion 30 described above. In other words, it can be said that the rotor core 112 forms the cam portion 30. The rotor core 112 is supported so as to be rotatable around the axis L via the bearing 35 and the bearing 36 in the same manner as the cam portion 30 described above. The rotor core 112 supports the third crown gear 23 obliquely with respect to a plane orthogonal to the axis L via the rolling elements 33. The rotor core 112 may be configured to be divided into the first cam 31 and the second cam 32 in the same manner as the cam portion 30 described above.

According to the transmission 1B having the above configuration, when the outer rotor 110 of the motor 2B is rotated, the third crown gear 23 supported by the rotor core 112 (cam portion 30) performs a wave motion (that is, the third crown gear 23 is moved). Precession exercise). Along with the wave motion of the third crown gear 23, the meshing position of the first crown gear 21 and the third crown gear 23 and the meshing position of the third crown gear 23 and the second crown gear 22 move in the circumferential direction. To do. With such wave motion of the third crown gear 23, the third crown gear 23 rotates around the axis L relative to the first crown gear 21 by the difference in the number of teeth of both. Further, the second crown gear 22 rotates about the axis L relative to the third crown gear 23 by the difference in the number of teeth of both. That is, a reduction ratio similar to that in the above-described embodiment can be obtained.

According to the third embodiment, since the motor 2B that rotates the cam portion 30 is provided on the inner side in the radial direction of the cam portion 30 in addition to the same effects as the above-described embodiment, for example, FIG. Compared with the transmission 1 shown in FIG. 2, the axial dimension of the transmission 1B is compact.

The motor 2B is further arranged on the inner side in the radial direction of at least one of the first crown gear 21, the second crown gear 22, and the third crown gear 23 (all in the example shown in FIG. 11). The motor 2B is disposed at an axial position overlapping with the first crown gear 21, the second crown gear 22, and the third crown gear 23, which can contribute to a reduction in the size of the transmission 1B in the axial direction.

Further, since the motor 2B includes the outer rotor 110 integrated with the cam portion 30, it is not necessary to configure the cam portion 30 and the outer rotor 110 as separate parts divided in the radial direction, and the diameter of the transmission 1B. It can contribute to the compactness of the dimension in the direction.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

FIG. 12 is a longitudinal sectional view of a transmission 1C according to the fourth embodiment of the present invention.
A transmission device 1 C according to the fourth embodiment includes a motor 2 C that rotates the cam portion 30 inside the cam portion 30 in the radial direction. Further, the transmission 1 C of the fourth embodiment includes a third crown gear 23 C supported by the cam portion 30 on the side opposite to the first crown gear 21. The transmission 1C of the fourth embodiment includes a second crown gear 22C that meshes with the third crown gear 23C on the same side as the first crown gear 21. That is, the third crown gear 23C of the fourth embodiment has the opposing teeth 23a facing the first crown gear 21 and the opposing teeth 23b facing the second crown gear 22C on the same side in the axial direction.

The third crown gear 23C has opposing teeth 23b on the outer side in the radial direction of the opposing teeth 23a. An annular groove 23f is formed between the opposing tooth 23a and the opposing tooth 23b. The second crown gear 22 C that meshes with the opposing teeth 23 b of the third crown gear 23 C is disposed on the outer side in the radial direction of the first crown gear 21. In other words, the first crown gear 21 is disposed inside the radial direction of the third crown gear 23C. The third crown gear 23C is supported so as to be rotatable around the axis L via the bearing 15 described above.

The opposite side of the third crown gear 23C from the surface where the opposing

teeth

23a and 23b are formed is an inclined surface 23e inclined with respect to a plane orthogonal to the axis L. The rolling element rolling groove 23c mentioned above is formed in the peripheral part of the inclined surface 23e. The rolling element rolling groove 23c is opposed to the rolling element rolling groove 32c formed in the cam portion 30 in the axial direction. The rolling element rolling groove 32c is formed in the peripheral part of the inclined surface 212b formed in parallel with the inclined surface 23e. Between the rolling element rolling groove 23c and the rolling element rolling groove 32c, a plurality of rolling elements 33 are arranged around the axis L so as to be capable of infinite circulation.

The cam portion 30 is disposed on the inclined surface 23e side of the third crown gear 23C (on the side opposite to the formation surface of the opposing teeth 23a and the opposing teeth 23b). Further, the cam portion 30 is formed in a disk shape having substantially the same diameter as the third crown gear 23C. That is, the cam portion 30 is not arranged on the inner side in the radial direction of the third crown gear 23C, and further, is not arranged on the inner side in the radial direction of the first crown gear 21 and the second crown gear 22C. The cam portion 30 is supported so as to be rotatable around the axis L via a bearing 16 (see FIG. 2) supported by the housing 10 (not shown in FIG. 12).

The motor 2C for rotating the cam portion 30 is disposed inside the cam portion 30 in the radial direction. The motor 2C is an outer rotor type motor similar to the motor 3B of the third embodiment described above. The motor 2 C includes a stator 200 provided with a plurality of coils 202 and an outer rotor 210 provided with a plurality of permanent magnets 211. The coil 202 can be provided on the outer rotor 210 and the permanent magnet 211 can be provided on the stator 200.

The stator 200 has a stator core 201 and a coil 202 supported by the stator core 201. The stator core 201 is formed in an annular shape coaxial with the axis L. On the circumferential surface of the stator core 201, a plurality of teeth 201a (saliency poles) extending outward in the radial direction are formed. A coil 202 is wound around the teeth 201a.

A second cylindrical support member 220 having a step 222 formed on the outer peripheral surface is fitted inside the stator core 201 in the radial direction. The second cylindrical support member 220 is fixed to the upper end portion of the above-described cylindrical support member 43 through bolts 46. The second cylindrical support member 220 extends upward along the axis L from the upper end portion of the cylindrical support member 43. Further, the lower end portion of the second cylindrical support member 220 is a flange 221 whose diameter is increased outward in the radial direction.

The flange 221 extends radially outward from the upper end of the cylindrical support member 43 and is in contact with the bearing 35 in the axial direction. The bearing 35 is supported by a cylindrical sleeve 230 that is extrapolated to the cylindrical support member 43. A step 231 that supports the bearing 35 in the axial direction is formed on the outer peripheral surface of the sleeve 230. Further, the lower end portion of the sleeve 230 is in contact with the first one-way clutch 41 in the axial direction. The flange 221 sandwiches the bearing 35 in the axial direction together with the sleeve 230 and has the same function as the press plate 45 described above, and the first one-way clutch 41, the spacer 44, and the second one-way are interposed via the sleeve 230. The clutch 42 is sandwiched in the axial direction.

The outer rotor 210 has a permanent magnet 211 and a rotor core 212 that supports the permanent magnet 211. The permanent magnet 211 is opposed to the teeth 201a of the stator core 201 with a gap in the radial direction. The permanent magnet 211 is fixed to the inner peripheral surface of a through hole 212a that penetrates the center of the rotor core 212 in the axial direction.

The rotor core 212 is integrated with the cam portion 30 described above. In other words, it can be said that the rotor core 212 forms the cam portion 30. Since the structure of the rotor core 212 is the same as the structure of the cam part 30 mentioned above, the description is omitted.

According to the transmission 1C configured as described above, when the outer rotor 210 of the motor 2C is rotated, the third crown gear 23C supported by the rotor core 212 (cam portion 30) performs a wave motion (that is, the third crown gear 23 is moved). Precession exercise). Along with the wave motion of the third crown gear 23C, the meshing location of the first crown gear 21 and the third crown gear 23C and the meshing location of the third crown gear 23 and the second crown gear 22C move in the circumferential direction. To do. With such wave motion of the third crown gear 23C, the third crown gear 23C rotates about the axis L relative to the first crown gear 21 by the difference in the number of teeth of both. Further, the second crown gear 22C rotates about the axis L relative to the third crown gear 23C by the difference in the number of teeth of both. That is, a reduction ratio similar to that in the above-described embodiment can be obtained.

According to the fourth embodiment described above, in addition to the same functions and effects as those of the above-described embodiment, the motor 2C that rotates the cam portion 30 is provided inside the cam portion 30 in the radial direction. Similar to the third embodiment, the dimension of the transmission 1C in the axial direction becomes compact.

In the present embodiment, the motor 2B includes the outer rotor 210 that is integrated with the cam portion 30. Therefore, it is not necessary to configure the cam portion 30 and the outer rotor 210 as separate parts divided in the radial direction. This can contribute to a reduction in the size of the transmission 1C in the radial direction.

In the present embodiment, since the second crown gear 22C meshing with the third crown gear 23C is provided on the same side as the first crown gear 21, the output is taken out from the same side as the first crown gear 21 (transmission gear). Can do.

The preferred embodiment of the present invention has been described above with reference to the drawings, but the present invention is not limited to the above embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the above-described embodiment, the configuration in which the first crown gear 21 has the two

transmission gears

21A and 21B has been described, but the first crown gear 21 may have three or more transmission gears having different numbers of teeth. Good.
Further, the plurality of transmission gears may be on the second crown gear 22 side instead of the first crown gear 21 side (a configuration in which the reduction ratio is switched on the output side may be employed).

For example, in the first embodiment, the configuration using the non-powered one-way clutch as the switching mechanism 40 has been described. However, an electric one-way clutch may be used. The electric one-way clutch is arranged, for example, in a gap between the first transmission gear 21A and the second transmission gear 21B, and rotates one of the transmission gears to fix the other transmission gear. Also good.

DESCRIPTION OF SYMBOLS 1 Transmission 1A Transmission 2 Motor 2B Motor 2C Motor 2a Rotating shaft 10 Housing 21 First crown gear 21A First transmission gear 21a Opposing tooth 21a1 Inclined surface 21B Second transmission gear 21b Opposing tooth 21b1 Inclining surface 22 Second crown gear 22a Counter tooth 23 Third crown gear

23a Counter tooth

23b Counter tooth 30 Cam part 40 Switching mechanism 40A Switching mechanism 41 First one-way clutch 41A Wedge part 42 Second one-way clutch 42A Movable part 43A Inclined part 100 Stator 110 Outer rotor 200 Stator 210 Outer Rotor L Axis P1 First fixed position P2 Second fixed position α Angle

Claims

The first crown gear,
A second crown gear,
A third crown gear having opposing teeth facing the first crown gear and opposing teeth facing the second crown gear;
The third crown gear with respect to the first crown gear and the second crown gear so that the third crown gear meshes with the first crown gear and the third crown gear meshes with the second crown gear. And a cam portion that wave-moves the third crown gear so that the inclining and meshing portions move in the circumferential direction,
Either one of the first crown gear and the second crown gear has a plurality of transmission gears with different numbers of teeth divided in the radial direction,
A transmission device comprising a switching mechanism for switching a transmission gear to be fixed from among the plurality of transmission gears.
The transmission according to claim 1, wherein the switching mechanism switches the fixed transmission gear according to a rotation direction.
The plurality of transmission gears include a first transmission gear and a second transmission gear,
The switching mechanism is
A first one-way clutch that rotates the first transmission gear in only one direction;
The transmission according to claim 2, further comprising: a second one-way clutch that rotates the second transmission gear in only one direction opposite to the first transmission gear.
The plurality of transmission gears include a first transmission gear and a second transmission gear,
The switching mechanism is
A wedge portion that is inserted into a gap between the first transmission gear and the second transmission gear and includes an inclined portion that can be brought into contact with the first transmission gear and the second transmission gear by moving in the axial direction;
2. The movable portion that moves the wedge portion in an axial direction between a first fixed position for fixing the first transmission gear and a second fixed position for fixing the second transmission gear. Or the transmission of 2.
The transmission according to any one of claims 1 to 4, wherein the plurality of transmission gears include a transmission gear having the same number of teeth as the opposing teeth of the third crown gear.
The transmission according to any one of claims 1 to 5, further comprising a motor that rotates the cam portion on a radially inner side of the cam portion.
The transmission according to claim 6, wherein the motor is further disposed on a radially inner side of at least one of the first crown gear, the second crown gear, and the third crown gear.
A motor having a stator and an outer rotor;
The transmission according to any one of claims 1 to 7, wherein the outer rotor and the cam portion are integrated.