JP2022096226A - Speed reduction mechanism - Google Patents

Abstract

To provide a speed reduction mechanism capable of operating continuously and appropriately.SOLUTION: A speed reduction mechanism comprises: a fixed gear 3 having a flat surface part 3a, and a cylindrical roller 10 provided on the flat surface part 3a; a flexible gear 4 having a flat surface part 4a facing the flat surface part 3a in an axial direction and elastically deforming in the axial direction, and a tooth part 14 provided on the flat surface part 4a and arranged in an annular manner around a central axis; and a pressing part 5 that rotates around the central axis, and presses the flat surface part 4a toward the flat surface part 3a to engage the tooth part 14 with respect to the cylindrical roller 10. The cylindrical roller 10 is provided so as to be immovable in a circumferential direction with respect to the flat surface part 3a and to be rollable with a radial direction as an axis.SELECTED DRAWING: Figure 3

Description

The present invention relates to a deceleration mechanism.

As a reduction mechanism, a wave gear having a high reduction ratio is known. Some wave gears have a structure that changes the meshing of the teeth in the thrust direction. This type of wave gear is, for example, an input shaft and an output shaft extending in the axial direction, a rotary pressing member provided on the input shaft, a flexible gear having flexibility provided on the output shaft, and flexibility. It is provided with a fixed gear that faces the gear in the axial direction.

As the rotary pressing member rotates about the axis on the flexible gear, a part of the flexible gear is pressed toward the fixed gear. As a result, the fixed gear and the flexible gear are meshed with each other. As the rotary pressing member rotates, the meshing point between the fixed gear and the flexible gear shifts, and the flexible gear rotates about the axis with respect to the fixed gear. As a result, the rotation of the output shaft is decelerated with respect to the rotation of the input shaft.

Here, the portion not pressed by the rotary pressing member of the flexible gear is separated from the fixed gear by the restoring force (elastic force) of the flexible gear. As a result, the meshing between the fixed gear and the flexible gear is released, so that the meshing portion between the fixed gear and the flexible gear is smoothly displaced due to the rotation of the rotary pressing member.

Japanese Unexamined Patent Publication No. 2020-3017

In the above-mentioned prior art, the disengagement of the fixed gear and the flexible gear depends on the restoring force of the flexible gear. Therefore, the flexible gear needs to have a strength that can be properly disengaged from the fixed gear at all times. For example, if the meshing resistance between the fixed gear and the flexible gear is large or the restoring force is weakened due to aged deterioration of the flexible gear, the deceleration mechanism may not operate properly.

The present invention provides a deceleration mechanism capable of continuously and properly operating.

The deceleration mechanism according to one aspect of the present invention has a first plane portion orthogonal to the axial direction, and a first tooth portion provided on the first plane portion and arranged in an annular shape around the axis. The gear, the second plane portion facing the first plane portion in the axial direction and elastically deforming in the axial direction, and the second tooth provided on the second plane portion and arranged in an annular shape around the axis. A second gear having a portion and a pressing portion that rotates around the axis and presses the second flat surface portion toward the first flat surface portion to engage the second tooth portion with the first tooth portion. And, at least one of the first tooth portion and the second tooth portion is composed of a plurality of rolling elements that are meshed with the other, and the rolling element is the first gear and the second gear. It is provided so that it can roll around the radial direction orthogonal to the circumferential direction.

In this way, at least one of the first tooth portion and the second tooth portion was composed of a rolling element. Therefore, when the meshing portion between the first tooth portion and the second tooth portion is displaced, the rolling element rotates with respect to the first tooth portion at the portion where the first tooth portion and the second tooth portion do not mesh with each other. The second tooth part becomes easier to ride on. Therefore, the meshing between the first tooth portion and the second tooth portion can be released regardless of the restoring force of the second flat surface portion. As a result, the deceleration mechanism can be continuously and properly operated without increasing the strength of the second gear.

In the above configuration, either one of the first tooth portion and the second tooth portion is composed of a plurality of rolling elements that are meshed with the other, and the rolling element is a cylindrical roller about the radial axis. The tooth bottom of either the first tooth portion or the second tooth portion may be formed in an arc shape corresponding to the shape of the rolling element.

In the above configuration, the tooth tip of either the first tooth portion or the second tooth portion may be formed in an arc shape.

With the above configuration, the rolling element may be provided on the first gear.

In the above configuration, the pressing portion may include a support shaft extending in the radial direction and a roller rotatably supported by the support shaft and pressing the second flat surface portion toward the first flat surface portion. good.

In the above configuration, the pressing portion includes a cam, and the cam protrudes from the plate portion toward the second gear and the plate portion rotating around the axis, and the second plane portion is referred to as the first plane portion. It may have a convex portion that is pressed toward.

With the above configuration, a thrust roller bearing provided between the second gear and the cam and provided in an annular shape around the axis may be provided.

With the above configuration, a resistance reducing layer provided on at least one of the facing surfaces of the second gear and the convex portion may be provided to reduce the contact resistance between the second gear and the convex portion.

In the above configuration, the second gear may have a shaft provided so as to project coaxially with the axis from the second plane portion.

The deceleration mechanism according to another aspect of the present invention has a first plane portion orthogonal to the axial direction, and a plurality of first tooth portions provided on the first plane portion and arranged in an annular shape around the axis. A gear, a second plane portion facing the first plane portion in the axial direction and elastically deforming in the axial direction, and a second plane portion provided on the second plane portion and arranged in an annular shape around the axis. A second gear having a tooth portion and a pressing force that rotates around the axis and presses the second flat surface portion toward the first flat surface portion to engage the second tooth portion with respect to the first tooth portion. The first tooth portion is provided with a portion, and the movement of the first tooth portion in the circumferential direction with respect to the first plane portion is restricted by a cage, and the first tooth portion can roll about a radial direction orthogonal to the circumferential direction of the first plane portion. The tooth bottom of the second tooth portion is formed in an arc shape corresponding to the shape of the cylindrical roller, and the tooth tip of the second tooth portion is formed in an arc shape. The pressing portion has a support shaft extending in the radial direction and a roller rotatably supported by the support shaft.

In this way, the first tooth portion was composed of a cylindrical roller. Therefore, when the meshing portion between the first tooth portion and the second tooth portion is displaced, the cylindrical roller rotates with respect to the first tooth portion at the portion where the first tooth portion and the second tooth portion do not mesh with each other. The second tooth part becomes easier to ride on. Therefore, the meshing between the first tooth portion and the second tooth portion is released regardless of the restoring force of the second flat surface portion. As a result, the deceleration mechanism can be continuously and properly operated without increasing the strength of the second gear.
Further, by forming the tooth bottom of the second tooth portion in an arc shape corresponding to the shape of the cylindrical roller, the meshing area (contact area) between the first tooth portion and the second tooth portion can be made as large as possible. .. Therefore, the surface pressure when the first tooth portion and the second tooth portion mesh with each other can be reduced. Therefore, the load applied to the first gear and the second gear can be reduced, and the gears can be continuously and properly operated without increasing the strength of the gears.
Further, by forming the tooth tip of the second tooth portion in an arc shape, it is possible to make it easier for the second tooth portion to ride on the cylindrical roller. Therefore, the meshing between the first tooth portion and the second tooth portion can be surely released.
Since the strength of the first gear is higher than that of the second gear (second plane portion) that is elastically deformed, it is possible to easily provide a cylindrical roller.
Since the pressing portion has a support shaft extending in the radial direction and a roller rotatably supported by the support shaft, the contact resistance of the pressing portion with respect to the second gear can be reduced. Therefore, the pressing portion and the second gear can be efficiently operated. In addition, the life of the second gear and the pressing portion can be extended by the amount that the contact resistance can be reduced.

The deceleration mechanism according to another aspect of the present invention has a first plane portion orthogonal to the axial direction, and a plurality of first tooth portions provided on the first plane portion and arranged in an annular shape around the axis. A gear, a second plane portion facing the first plane portion in the axial direction and elastically deforming in the axial direction, and a second gear provided on the second plane portion and arranged in an annular shape around the axis. A second gear having a tooth portion and a pressing force that rotates around the axis and presses the second flat surface portion toward the first flat surface portion to engage the second tooth portion with respect to the first tooth portion. A thrust roller bearing provided between the second gear and the pressing portion and provided in an annular shape around the axis is provided, and the first tooth portion is provided with the first flat surface by a cage. It is a cylindrical roller that is restricted from moving in the circumferential direction with respect to the portion and is rotatably provided about the radial direction orthogonal to the circumferential direction of the first plane portion, and the tooth bottom of the second tooth portion is the said. It is formed in an arc shape corresponding to the shape of a cylindrical roller, the tip of the second tooth portion is formed in an arc shape, the pressing portion is a cam, and the cam rotates around the axis. It has a plate portion to be formed and a convex portion protruding from the plate portion toward the second gear.

In this way, the first tooth portion was composed of a cylindrical roller. Therefore, when the meshing portion between the first tooth portion and the second tooth portion is displaced, the cylindrical roller rotates with respect to the first tooth portion at the portion where the first tooth portion and the second tooth portion do not mesh with each other. The second tooth part becomes easier to ride on. Therefore, the meshing between the first tooth portion and the second tooth portion is released regardless of the restoring force of the second flat surface portion. As a result, the deceleration mechanism can be continuously and properly operated without increasing the strength of the second gear.
Further, by forming the tooth bottom of the second tooth portion in an arc shape corresponding to the shape of the cylindrical roller, the meshing area (contact area) between the first tooth portion and the second tooth portion can be made as large as possible. .. Therefore, the surface pressure when the first tooth portion and the second tooth portion mesh with each other can be reduced. Therefore, the load applied to the first gear and the second gear can be reduced, and the gears can be continuously and properly operated without increasing the strength of the gears.
Further, by forming the tooth tip of the second tooth portion in an arc shape, it is possible to make it easier for the second tooth portion to ride on the cylindrical roller. Therefore, the meshing between the first tooth portion and the second tooth portion can be surely released.
Since the strength of the first gear is higher than that of the second gear (second plane portion) that is elastically deformed, it is possible to easily provide a cylindrical roller.
The pressing portion is a cam, and the cam has a plate portion that rotates around an axis and a convex portion that protrudes from the plate portion toward the second gear. Therefore, the configuration of the pressing portion can be simplified. In addition, the pressing portion can be flattened.

The deceleration mechanism described above can be continuously and properly operated.

The cross-sectional view along the axial direction of the wave gear mechanism in 1st Embodiment of this invention. Partially exploded perspective view of the strain wave gearing mechanism according to the first embodiment of the present invention. Explanatory drawing which developed fixed gear and flexible gear in 1st Embodiment of this invention. The cross-sectional view along the axial direction of the wave gear mechanism in the 2nd Embodiment of this invention. Partially exploded perspective view of the strain wave gearing mechanism according to the third embodiment of the present invention. The side view which shows the structure of the pressing part in 3rd Embodiment of this invention.

Next, an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]
<Strain wave gearing mechanism>
FIG. 1 is a cross-sectional view taken along the axial direction of the strain wave gearing mechanism 1 according to the reduction mechanism according to the first embodiment. FIG. 2 is a partially disassembled perspective view of the strain wave gearing mechanism 1.
As shown in FIGS. 1 and 2, the wave gear mechanism 1 includes a bottomed cylindrical case 2 and a disk-shaped fixed gear provided so as to close the opening 2a of the case 2 (the first in the claim). 1) 3 as an example of a gear, a flexible gear (an example of a second gear in the claim) 4 provided in a case 2, and a pressing portion 5 are mainly configured.
In the following description, the direction parallel to the central axis C of the case 2 is referred to as an axial direction. Further, the circumferential direction (around the central axis C) of the case 2, the fixed gear 3, and the flexible gear 4 may be simply referred to as a circumferential direction, and the radial direction of the case 2 may be simply referred to as a radial direction.

<Case>
A cylindrical bearing housing 6 projecting toward the opening 2a is integrally formed in the center of the bottom portion 2b of the case 2 in the radial direction. The bearing housing 6 is provided with two bearings 7a and 7b for rotatably supporting the input shaft 17 described later. As the bearings 7a and 7b, for example, ball bearings can be preferably used. However, the present invention is not limited to this, and various bearings such as other rolling bearings and slide bearings can be used.
At the end of the case 2 on the side of the opening 2a, an enlarged diameter portion 8 having an enlarged inner diameter is formed via a stepped portion 2c. A fixed gear 3 is provided so as to be fitted to the enlarged diameter portion 8.

<Fixed gear>
The fixed gear 3 has a disk-shaped fixed gear body 9 whose radial center coincides with the central axis C of the case 2 and a flat surface portion (first step portion 2c) side of the fixed gear body 9. Example of a flat surface portion) A plurality of cylindrical rollers 10 and a cage 11 provided on 9a are mainly configured.
The plurality of cylindrical rollers 10 are arranged so that the axial direction of the cylindrical rollers 10 coincides with the radial direction of the case 2, and are arranged at equal intervals in the circumferential direction. That is, the plurality of cylindrical rollers 10 are arranged radially when viewed from the axial direction.

The cage 11 holds the plurality of cylindrical rollers 10 so that they cannot move in the circumferential direction with respect to the flat surface portion 9a and can roll around the axis of the cylindrical rollers 10.
Under such a configuration, the cylindrical roller 10 functions as a tooth portion (an example of the first tooth portion in the claim) that is meshed with the flexible gear 4 (details will be described later).

A through hole 9b is formed in the radial center of the fixed gear body 9 so as to penetrate in the thickness direction (axial direction) of the fixed gear body 9. A bearing 12 is provided in the through hole 9b. As the bearing 12, for example, a ball bearing can be preferably used. However, the present invention is not limited to this, and various bearings such as other rolling bearings and slide bearings can be used. An output shaft (an example of a shaft in a claim) 13 is rotatably supported by a fixed gear 3 via such a bearing 12.

The output shaft 13 is formed in a solid state. The axis of the output shaft 13 coincides with the central axis C. Most of the output shaft 13 is projected to the opposite side of the case 2 via the fixed gear 3. The flexible gear 4 is fixed to one end 13a protruding toward the case 2 of the output shaft 13, and the flexible gear 4 is rotated integrally with the output shaft 13. In other words, the output shaft 13 projects from the flat surface portion 4a of the flexible gear 4.

<Flexible gear>
FIG. 3 is an explanatory view of the fixed gear 3 and the flexible gear 4 developed.
As shown in FIGS. 1 to 3, the flexible gear 4 is formed in a disk shape by an elastically deformable material. The flexible gear 4 is arranged so as to face the flat surface portion 9a of the fixed gear body 9 in the axial direction. The radial center of the flexible gear 4 coincides with the central axis C, and one end 13a of the output shaft 13 is fixed to the radial center. The radial inside of the fixed flexible gear 4 is the fixed end, and the outer peripheral side of the flexible gear 4 is the free end. Then, the flexible gear 4 is elastically deformed along the axial direction so that the outer peripheral portion of the flexible gear 4 approaches and separates from the fixed gear 3.

Further, when viewed from the axial direction, the outer peripheral portion of the flexible gear 4 overlaps with the cylindrical roller 10. The outer peripheral portion of the flexible gear 4 is meshed with a plurality of cylindrical rollers 10 on a flat surface portion (an example of the second flat surface portion in the claim) 4a that faces the flat surface portion 9a of the fixed gear body 9 in the axial direction. The tooth portion (an example of the second tooth portion in the claim) 14 is formed over the entire circumference. The tooth width of the tooth portion 14 is along the radial direction. The tooth width of the tooth portion 14 is preferably about the same as the length of the cylindrical roller 10. The number of teeth of the tooth portion 14 is smaller than the number of cylindrical rollers 10. For example, the number of teeth of the tooth portion 14 is two less than the number of cylindrical rollers 10.

The tooth bottom 14a of the tooth portion 14 is formed in an arc shape so as to correspond to the shape of the cylindrical roller 10. More specifically, the radius of curvature of the tooth base 14a is equivalent to the radius of the cylindrical roller 10.
The tooth tip 14b of the tooth portion 14 is also formed in an arc shape. The radius of curvature of the tooth tip 14b is also equivalent to the radius of curvature of the tooth bottom 14a.
Such flexible gears 4 are arranged at regular intervals in the axial direction from the fixed gears 3. Specifically, the top 14c of the tooth tip 14b of the tooth portion 14 is slightly separated from or slightly in contact with the cylindrical roller 10 in a natural state in which the flexible gear 4 is not loaded. The flexible gear 4 is arranged so as to be a degree. Further, the pressing portion 5 is arranged on the side opposite to the fixed gear 3 with the flexible gear 4 interposed therebetween.

<Pressing part>
The pressing portion 5 includes two support shafts 15 fixed to an input shaft 17 rotatably supported by the case 2 via bearings 7a and 7b, and a roller 16 rotatably supported by the support shaft 15. Be prepared.
The input shaft 17 is formed in a solid shape. The axis of the input axis 17 coincides with the central axis C. In this way, the input shaft 17 is arranged coaxially with the output shaft 13. A shaft fixing seat 18 is provided at the end of the input shaft 17 on the flexible gear 4 side. The shaft fixing seat 18 is formed so that the size in the radial direction is larger than the outer diameter of the input shaft 17. One end 15a of the support shaft 15 is attached to such a shaft fixing seat 18.

The two support shafts 15 extend along the radial direction. Further, the two support shafts 15 are arranged on both sides of the input shaft 17 (shaft fixed seat 18) and on the same straight line. The roller 16 is rotatably supported by the other end (radial outer end) 15b of each support shaft 15.
The roller 16 is for pressing the flexible gear 4 from the back surface 4b side opposite to the flat surface portion 4a toward the fixed gear 3. The roller 16 is arranged at a position where it overlaps with the tooth portion 14 of the flexible gear 4 and the cylindrical roller 10 of the fixed gear 3 when viewed from the axial direction.

<Operation of strain wave gearing>
Next, the operation of the wave gear mechanism 1 will be described.
First, the tooth portion 14 of the flexible gear 4 is engaged with the cylindrical roller 10 of the fixed gear 3 only at the pressed portion by the back surface 4b being pressed by the roller 16. From such a state, for example, when a motor (not shown) is connected to the input shaft 17 and the input shaft 17 is rotated by this motor, the roller 16 of the pressing portion 5 is integrated with the input shaft 17 around the central axis C. Rotate.

Then, as the roller 16 rotates around the central axis C, the meshing position between the cylindrical roller 10 of the fixed gear 3 and the tooth portion 14 of the flexible gear 4 is gradually changed. The number of teeth of the tooth portion 14 is, for example, two less than the number of the cylindrical rollers 10. Therefore, as the meshing position gradually shifts in the circumferential direction, the meshing between the cylindrical roller 10 of the fixed gear 3 and the tooth portion 14 of the flexible gear 4 shifts, and the differential amount can be applied to the fixed gear 3. The flexible gear 4 is rotated. Specifically, when the roller 16 rotates once, the flexible gear 4 rotates with respect to the fixed gear 3 by two cylindrical rollers 10.

Here, when the meshing between the cylindrical roller 10 of the fixed gear 3 and the tooth portion 14 of the flexible gear 4 is displaced (see, for example, the arrow Y1 in FIG. 3), the cylindrical roller 10 rolls around the axis along with this displacement operation. It is moved (see, for example, arrow Y2 in FIG. 3). Therefore, the meshing resistance between the cylindrical roller 10 and the tooth portion 14 is reduced as much as possible, and in the place where the flexible gear 4 is not pressed by the roller 16, the tooth portion 14 is not affected by the restoring force of the flexible gear 4. Easily rides on the cylindrical roller 10. Moreover, since the tooth tip 14b of the tooth portion 14 is formed in an arc shape, the tooth portion 14 can easily ride on the cylindrical roller 10. Even if the top 14c of the tooth tip 14b of the tooth portion 14 is slightly in contact with the cylindrical roller 10 at a position where the cylindrical roller 10 and the tooth portion 14 are not meshed with each other, the tooth portion 14 is caught by the cylindrical roller 10. It never ends up.

Further, the tooth bottom 14a of the tooth portion 14 is formed in an arc shape so as to correspond to the shape of the cylindrical roller 10. Therefore, in the place where the cylindrical roller 10 and the tooth portion 14 are meshed with each other, the contact area between the cylindrical roller 10 and the tooth portion 14 becomes larger than in the case where the tooth portion 14 is formed in a trapezoidal shape. Therefore, the surface pressure applied to the cylindrical roller 10 and the tooth portion 14 is reduced, and the cylindrical roller 10 and the tooth portion 14 are surely meshed with each other.
Further, since the flexible gear 4 is pressed by the roller 16, even if the roller 16 is rotated around the central axis C, the roller 16 is rotated (see, for example, the arrow Y3 in FIG. 3), so that the flexible gear 4 is pressed. The contact resistance (sliding resistance) of the pressing portion 5 against the pressure is reduced as much as possible.

When the flexible gear 4 is rotated, the output shaft 13 is rotated integrally with the flexible gear 4. The rotation of the output shaft 13 is decelerated with respect to the rotation of the input shaft 17 and is output. By attaching an external device (not shown) to the output shaft 13, this external device is driven. It is also possible to fix the output shaft 13 and attach an external device (not shown) to the case 2. With this configuration, the fixed gear 3 is rotated with respect to the flexible gear 4. Since the case 2 is rotated by the fixed gear 3, an external device is driven.

As described above, in the above-mentioned first embodiment, a plurality of cylindrical rollers 10 are radially arranged on the flat surface portion 9a of the fixed gear main body 9 constituting the fixed gear 3. The fixed gear body 9 is not elastically deformed and has higher strength than the flexible gear 4. Therefore, the cylindrical roller 10 can be easily provided on the flat surface portion 9a of the fixed gear main body 9.

Then, such a cylindrical roller 10 was made to function as a first tooth portion to be meshed with the tooth portion 14 of the flexible gear 4. The cage 11 makes the cylindrical roller 10 immovable in the circumferential direction with respect to the flat surface portion 9a of the fixed gear body 9 and rolls around the axis of the cylindrical roller 10.
Therefore, the tooth portion 14 can easily ride on the cylindrical roller 10 at the position where the cylindrical roller 10 and the tooth portion 14 are not meshed with each other. Therefore, the meshing between the cylindrical roller 10 and the tooth portion 14 can be released regardless of the restoring force of the flexible gear 4. As a result, for example, the strain wave gear mechanism 1 can be continuously and properly operated without increasing the strength of the flexible gear 4.

In addition to this, the tooth tip 14b of the tooth portion 14 is formed in an arc shape. Therefore, it is possible to further facilitate the riding on the cylindrical roller 10 of the tooth portion 14. Therefore, the meshing between the cylindrical roller 10 and the tooth portion 14 can be reliably released.

Further, in the flexible gear 4, the tooth bottom 14a of the tooth portion 14 is formed in an arc shape so as to correspond to the shape of the cylindrical roller 10. Therefore, in the place where the cylindrical roller 10 and the tooth portion 14 are meshed with each other, the contact area between the cylindrical roller 10 and the tooth portion 14 becomes larger than in the case where the tooth portion 14 is formed in a trapezoidal shape. Therefore, the surface pressure applied to the cylindrical roller 10 and the tooth portion 14 can be reduced, and the strain wave gear mechanism 1 can be continuously and appropriately operated without increasing the strength of the cylindrical roller 10 and the tooth portion 14. Further, the cylindrical roller 10 and the tooth portion 14 can be securely meshed with each other.

Further, a roller 16 is provided on the pressing portion 5, and the flexible gear 4 is pressed by using the roller 16. Therefore, the contact resistance of the pressing portion 5 with respect to the flexible gear 4 can be reduced. Therefore, the pressing portion 5 and the flexible gear 4 can be efficiently operated. Further, the life of the pressing portion 5 and the flexible gear 4 can be extended by the amount that the contact resistance can be reduced.

Further, one end 13a of the output shaft 13 is fixed to the radial center of the flexible gear 4. In other words, the output shaft 13 projects from the flat surface portion 4a of the flexible gear 4. The radial inside of the flexible gear 4 fixed to the output shaft 13 is the fixed end, and the outer peripheral side of the flexible gear 4 is the free end. Therefore, the outer peripheral portion of the flexible gear 4 can be easily elastically deformed in the axial direction. That is, since the radial inner side of the flexible gear 4 is constrained as a fixed end, the outer peripheral portion side, which is a free end, is greatly elastically deformed. If the radial inner side of the flexible gear 4 is also a free end, the elastic deformation on the outer peripheral portion side becomes small. In this way, the radial inner side of the flexible gear 4 becomes the fixed end, and the outer peripheral side of the flexible gear 4 becomes the free end, so that the restoring force of the flexible gear 4 is utilized to form the cylindrical roller 10. On the other hand, the tooth portions 14 can be reliably separated from each other. Therefore, the meshing between the cylindrical roller 10 and the tooth portion 14 can be reliably released.

In the first embodiment described above, the case where the output shaft 13 and the input shaft 17 are formed in a solid state has been described. However, the present invention is not limited to this, and the output shaft 13 and the input shaft 17 may be formed in a hollow shape.

Further, in the above-mentioned first embodiment, the case where the cage 11 is provided on the flat surface portion 9a of the fixed gear main body 9 has been described. A case has been described in which a plurality of cylindrical rollers 10 are held by the cage 11 so as to be immovable in the circumferential direction and rollable around the axis of the cylindrical rollers 10 with respect to the flat surface portion 9a. However, the present invention is not limited to this, and instead of the cage 11, a plurality of recesses may be formed in the flat surface portion 9a, and the cylindrical roller 10 may be arranged in the recesses. Even in such a configuration, the plurality of cylindrical rollers 10 can be held so as not to be movable in the circumferential direction with respect to the flat surface portion 9a and to be rollable around the axis of the cylindrical rollers 10.

In the above-mentioned first embodiment, the case where the cylindrical bearing housing 6 projecting toward the opening 2a side is integrally formed in the center of the bottom portion 2b of the case 2 has been described. However, the present invention is not limited to this, and the bearing housing 6 may be provided separately from the case 2.

[Second Embodiment]
<Strain wave gearing mechanism>
Next, a second embodiment of the present invention will be described with reference to FIG. The same reference numerals as those of the above-mentioned first embodiment are designated by the same reference numerals, and the description thereof will be omitted (the same applies to the following embodiments).
FIG. 4 is a cross-sectional view taken along the axial direction of the strain wave gearing mechanism 201 in the second embodiment.
As shown in FIG. 4, the strain wave gearing mechanism 201 mainly includes a case 202, a fixed gear 203, a flexible gear 204, and a pressing portion 205, as in the first embodiment described above. Is.

Here, the difference between the first embodiment and the second embodiment is that the output shaft 13 is provided on the flexible gear 4 in the first embodiment, whereas the flexible gear is provided in the second embodiment. The point is that the output shaft 13 is not provided on the 204. Further, in the first embodiment, the fixed gear 3 is fixed to the case 2, whereas in the second embodiment, the flexible gear 204 is fixed to the case 202.

<Case>
More specifically, the case 202 includes a bottomed cylindrical first case 21 arranged in the axial direction and an annular second case 22. The first case 21 is arranged with the opening 21a facing the second case 22 side. A through hole 23 penetrating in the thickness direction (axial direction) is formed in the center of the bottom portion 21b of the first case 21 in the radial direction. The input shaft 217 is passed through the through hole 23. Further, the through hole 23 is provided with a bearing 20 for rotatably supporting the input shaft 217. As the bearing 20, for example, a ball bearing can be preferably used. However, the present invention is not limited to this, and various bearings such as other rolling bearings and slide bearings can be used.

On the peripheral wall 21c of the first case 21, an outer flange portion 24 projecting outward in the radial direction is integrally formed on the opening 21a side. Most of the outer flange portion 24 is formed with a storage recess 25 having a circular shape when viewed from the axial direction. The diameter of the inner peripheral surface of the storage recess 25 is the same as the outer diameter of the second case 22. The flexible gear 204 is sandwiched and held by the bottom surface 25a of the storage recess 25 of the first case 21 and the end surface 22a of the second case 22 on the first case 21 side.

<Flexible gear>
The flexible gear 204 is integrally formed with an annular fixed portion 26 and a flexible gear main body 27 projecting radially inward from the inner peripheral surface of the fixed portion 26. The radial center of the flexible gear 204 coincides with the central axis C. The fixing portion 26 is sandwiched between the bottom surface 25a of the storage recess 25 of the first case 21 and the end surface 22a of the second case 22 on the first case 21 side. Through holes 26a, 25b, and 22c that penetrate in the axial direction are formed in the fixing portion 26, the storage recess 25 of the first case 21, and the second case 22, respectively. A fixing member such as a bolt (not shown) is passed through the through holes 26a, 25b, 22c, and the cases 21 and 22 and the flexible gear 204 are integrated.

Bearing storage recesses 26b and 22b are formed on the inner peripheral surface of the fixed portion 26 and the inner peripheral surface of the second case 22, respectively. Bearings 28 for rotatably supporting the fixed gear 203 are provided in the bearing storage recesses 26b and 22b.
Since the outer peripheral portion of the flexible gear body 27 is fixed to the fixed portion 26, the outer peripheral portion side is the fixed end, and the radial inner side is the free end. Then, the flexible gear 4 is elastically deformed along the axial direction (so as to approach and separate from the fixed gear 203) on the radial inside of the flexible gear body 27. Inside the flexible gear body 27 in the radial direction, there is a flat surface portion (an example of the second flat surface portion in the claim) 27a on the second case 22 side, and a tooth portion (second tooth portion in the claim) over the entire circumference. Example) 29 is formed.

<Fixed gear>
The fixed gear 203 is rotatably supported by the fixed portion 26 of the flexible gear 204 and the second case 22 via a bearing 28. The fixed gear 203 is formed in an annular shape. The radial center of the fixed gear 203 coincides with the central axis C.
The flat surface portion (an example of the first flat surface portion in the claim) 203a on the flexible gear body 27 side of the fixed gear 203 faces the flat surface portion 27a of the flexible gear body 27 in the axial direction. The flat surface portion 203a of the fixed gear 203 is formed with a plurality of recesses 203b at positions overlapping with the tooth portions 29 of the flexible gear main body 27 when viewed from the axial direction. The recess 203b has a rectangular shape that is long in the radial direction when viewed from the axial direction, and has a semicircular cross section along the axial direction and the circumferential direction. Such a plurality of recesses 203b are arranged at equal intervals in the circumferential direction. That is, the plurality of recesses 203b are arranged radially when viewed from the axial direction.

Cylindrical rollers 10 are arranged in each recess 203b. The shape of each recess 203b corresponds to the cylindrical roller 10, and its axis is along the radial direction. Then, the cylindrical roller 10 is held by the recess 203b so as to be immovable in the circumferential direction with respect to the flat surface portion 203a of the fixed gear 203 and to be rollable around the axis of the cylindrical roller 10. Under such a configuration, the cylindrical roller 10 functions as a first tooth portion that is meshed with the tooth portion 29 of the flexible gear body 27.

Here, although not particularly shown in the second embodiment, the tooth bottom of the tooth portion 29 of the flexible gear body 27 is formed in an arc shape so as to correspond to the shape of the cylindrical roller 10. That is, the radius of curvature of the tooth base of the tooth portion 29 is equivalent to the radius of the cylindrical roller 10. The tooth tips of the tooth portions 29 are also formed in an arc shape. The radius of curvature of the tooth tip is also equivalent to the radius of curvature of the tooth base 14a.
Such a flexible gear body 27 is arranged at a certain interval in the axial direction from the fixed gear 203. Specifically, in a natural state where the flexible gear body 27 is not loaded, the top of the tooth tip of the tooth portion 29 is slightly separated from or slightly in contact with the cylindrical roller 10. The flexible gear body 27 is arranged so as to be.

Further, the fixed gear 203 has a female threaded portion 30 formed on the other surface 203c on the opposite side of the flat surface portion 203a. The female thread portion 30 is used to fix an external device (not shown) to the fixed gear 203.
A bearing 31 for rotatably supporting the input shaft 217 is provided on the inner peripheral surface of the fixed gear 203. As the bearing 31, for example, a ball bearing can be preferably used. However, the present invention is not limited to this, and various bearings such as other rolling bearings and slide bearings can be used.

In this way, the input shaft 217 is rotatably supported by the bearing 31 provided in the fixed gear 203 and the bearing 20 provided in the first case 21. The input shaft 217 is passed through the first case 21, the flexible gear body 27, and the fixed gear 203. The input shaft 217 is formed in a hollow shape. A pressing portion 205 is provided at a position corresponding to the inside of the first case 21 on the outer peripheral portion of the input shaft 217.

<Pressing part>
The pressing portion 205 includes two support shafts 215 fixed to the input shaft 17 and rollers 216 rotatably supported by the support shaft 215.
The two support shafts 215 project along the radial direction from the outer peripheral portion of the input shaft 217. Further, the two support shafts 215 are arranged on both sides of the input shaft 217 and on the same straight line. The roller 216 is rotatably supported by the radial outer end portion 215b of each support shaft 215. The roller 216 is arranged at a position where it overlaps with the tooth portion 29 of the flexible gear body 27 and the cylindrical roller 10 of the fixed gear 203 when viewed from the axial direction.

<Operation of strain wave gearing>
Next, the operation of the strain wave gearing mechanism 201 will be described.
First, the roller 216 presses the back surface 27b of the flexible gear body 27 toward the fixed gear 203. Only the tooth portion 29 of the flexible gear body 27 at the pressed portion is meshed with the cylindrical roller 10 of the fixed gear 203. From such a state, for example, when a motor (not shown) is connected to the input shaft 217 and the input shaft 217 is rotated by this motor, the roller 216 of the pressing portion 205 is integrated with the input shaft 217 and rotates around the central axis C. Will be done.

Then, as the roller 216 rotates, the meshing position between the cylindrical roller 10 of the fixed gear 203 and the tooth portion 29 of the flexible gear body 27 is gradually changed. Since the number of teeth of the tooth portion 29 is, for example, two less than the number of the cylindrical roller 10, the meshing position gradually shifts in the circumferential direction, so that the tooth portion of the cylindrical roller 10 of the fixed gear 203 and the tooth portion of the flexible gear body 27 The mesh with 29 is out of alignment.

In the second embodiment, the flexible gear 204 is fixed to the case 202. Therefore, the fixed gear 203 is rotated with respect to the flexible gear 204 by the differential amount due to the deviation of the meshing between the cylindrical roller 10 of the fixed gear 203 and the tooth portion 29 of the flexible gear main body 27. Specifically, when the roller 216 rotates once, the fixed gear 203 rotates with respect to the flexible gear 204 by the number of two cylindrical rollers 10. By rotating the fixed gear 203, an external device (not shown) fixed to the fixed gear 203 is driven. That is, the fixed gear 203 functions as an output shaft that outputs the rotation of the input shaft 217 to an external device (not shown).

Therefore, according to the above-mentioned second embodiment, the same effect as that of the above-mentioned first embodiment can be obtained.
Further, by forming the input shaft 217 in a hollow shape and forming the fixed gear 203 in an annular shape, wiring or the like for supplying electric power to a motor (not shown) for driving the wave gear mechanism 201, for example, in the input shaft 217. Can be routed around. Therefore, it is possible to increase the degree of freedom in routing the wiring or the like provided around the strain wave gearing mechanism 201.

In the second embodiment described above, the case where the input shaft 217 is formed in a hollow shape has been described. Further, a case where the fixed gear 203 is formed in an annular shape has been described. However, the present invention is not limited to this, and the input shaft 217 may be formed in a solid state. Further, the fixed gear 203 may be formed in a disk shape.

In the second embodiment described above, the case where the recess 203b is formed in the flat surface portion 203a of the fixed gear 203 has been described. When the cylindrical roller 10 is arranged in the recess 203b so that the cylindrical roller 10 cannot be moved in the circumferential direction with respect to the flat surface portion 203a of the fixed gear 203 and can be rolled around the axis of the cylindrical roller 10. explained. However, the present invention is not limited to this, and a cage for holding the cylindrical roller 10 may be provided on the flat surface portion 203a of the fixed gear 203. By this cage, the cylindrical roller 10 may be held on the flat surface portion 203a so as to be immovable in the circumferential direction and rollable around the axis of the cylindrical roller 10.

[Third Embodiment]
<Strain wave gearing mechanism>
Next, a third embodiment of the present invention will be described with reference to FIGS. 5 and 6.
FIG. 5 is a partially exploded perspective view of the strain wave gearing mechanism 301 of the third embodiment.
As shown in FIG. 5, the strain wave gear mechanism 301 mainly includes a case (not shown in the third embodiment), a fixed gear 3, a flexible gear 4, and a pressing portion 305. , The same as the above-mentioned first embodiment.
Here, the difference between the first embodiment and the third embodiment is that the pressing portion 5 of the first embodiment and the pressing portion 305 of the third embodiment are different.

<Pressing part>
FIG. 6 is a side view showing the configuration of the pressing portion 305.
As shown in FIGS. 5 and 6, the pressing portion 305 is provided between the cam 40 provided at the end of the input shaft 17 on the flexible gear 4 side, and between the cam 40 and the flexible gear 4. An annular thrust roller bearing 43 is provided.

The cam 40 includes a disk body (an example of the plate portion in the claim) 41 provided coaxially with the input shaft 17, and a convex portion 42 protruding from the disk body 41 toward the flexible gear 4 side. Is integrally molded. The convex portion 42 is provided on the outer peripheral portion of the disk body 41. The convex portion 42 is formed so as to taper toward the flexible gear 4 side, and the ridge line portion 42a is along the radial direction. Such convex portions 42 are arranged on both sides of the input shaft 17 so that the ridge line portions 42a are located on the same straight line. Further, each convex portion 42 is arranged at a position where it overlaps with the tooth portion 14 of the flexible gear 4 and the cylindrical roller 10 of the fixed gear 3 when viewed from the axial direction.

The thrust roller bearing 43 is formed in a size located between the tooth portion 14 of the flexible gear 4 and the cylindrical roller 10 of the fixed gear 3 and each convex portion 42 in the axial direction. The radial center of the thrust roller bearing 43 coincides with the central axis C. The thrust roller bearing 43 includes a plurality of cylindrical rollers 44 arranged radially like the cylindrical rollers 10 of the fixed gear 3, and a cage 45 for holding the plurality of cylindrical rollers 44.

The cage 45 holds the plurality of cylindrical rollers 44 so that they cannot move in the circumferential direction and can roll around the axis of the cylindrical rollers 44. Further, the cage 45 is made of a material that elastically deforms. Therefore, the cage 45 is elastically deformed along the axial direction.

<Operation of strain wave gearing>
Next, the operation of the strain wave gearing mechanism 301 will be described.
First, the convex portion 42 of the cam 40 presses the back surface 4b of the flexible gear 4 toward the fixed gear 3 via the thrust roller bearing 43. Since the cage 45 of the thrust roller bearing 43 is elastically deformed, it is elastically deformed so as to follow the shape of the convex portion 42 of the cam 40. As a result, only the tooth portion 14 of the flexible gear 4 pressed by the convex portion 42 is meshed with the cylindrical roller 10 of the fixed gear 203.

From such a state, for example, when a motor (not shown) is connected to the input shaft 17 and the input shaft 17 is rotated by this motor, the cam 40 of the pressing portion 305 rotates around the central axis C integrally with the input shaft 17. Will be done. Since the convex portion 42 of the cam 40 is provided on the outer peripheral portion of the disk body 41, the convex portion 42 rotates around the central axis C.

Then, as the convex portion 42 rotates, the meshing position between the cylindrical roller 10 of the fixed gear 3 and the tooth portion 14 of the flexible gear 4 is gradually changed. Since the number of teeth of the tooth portion 14 is, for example, two less than the number of the cylindrical rollers 10, the meshing position gradually shifts in the circumferential direction, so that the cylindrical rollers 10 of the fixed gear 3 and the tooth portions 14 of the flexible gear 4 are gradually displaced. The flexible gear 4 is rotated with respect to the fixed gear 3 by the amount of the differential mesh with the fixed gear 3. Specifically, when the cam 40 makes one rotation, the flexible gear 4 rotates with respect to the fixed gear 3 by two cylindrical rollers 10. When the flexible gear 4 is rotated, the output shaft 13 is rotated integrally with the flexible gear 4.

Therefore, according to the above-mentioned third embodiment, the same effect as that of the above-mentioned first embodiment can be obtained.
Further, by configuring the pressing portion 305 with the cam 40, the configuration of the pressing portion 305 can be simplified. Further, the pressing portion 305 can be flattened as compared with the case where the roller 16 is used as in the first embodiment described above.
Further, the convex portion 42 of the cam 40 presses the back surface 4b of the flexible gear 4 via the thrust roller bearing 43. Therefore, the thrust roller bearing 43 reduces the contact resistance of the cam 40 with respect to the flexible gear 4. Therefore, the pressing portion 305 and the flexible gear 4 can be efficiently operated, and the life of the pressing portion 305 and the flexible gear 4 can be extended by the amount that the contact resistance can be reduced.

The cam 40 of the third embodiment may be used in place of the support shaft 215 and the roller 216 of the second embodiment.
Further, in the above-mentioned third embodiment, the case where the thrust roller bearing 43 is provided in order to reduce the contact resistance of the cam 40 with respect to the flexible gear 4 has been described. However, the present invention is not limited to this, and on at least one of the surface of the convex portion 42 (an example of the facing surface in the claim) and the back surface of the flexible gear 4 (here, an example of the facing surface in the claim) 4b. A resistance reducing layer 48 (indicated by a two-dot chain line) that reduces the contact resistance of the cam 40 to the flexible gear 4 may be provided. Examples of the resistance reducing layer 48 include a coating film and the like. The resistance reducing layer 48 is, for example, a fluororesin-coated film or the like. In addition, a slide bearing may be adopted as the resistance reduction layer 48.

The present invention is not limited to the above-described embodiment, and includes various modifications to the above-mentioned embodiment without departing from the spirit of the present invention.
For example, in the above-described embodiment, the case where the fixed gears 3 and 203 are provided with the cylindrical rollers 10 that are meshed with the tooth portions 14 and 29 of the flexible gears 4 and 204 has been described. However, the present invention is not limited to this, and the cylindrical roller 10 may be provided in place of the tooth portions 19 and 29 of the flexible gears 4, 204. Further, the fixed gears 3, 203 and the flexible gears 4, 204 may be provided with cylindrical rollers 10, and the cylindrical rollers 10 may be configured to mesh with each other.

Further, a sphere may be provided instead of the cylindrical roller 10. By configuring the sphere on the fixed gears 3, 203 and the flexible gears 4, 204 so that they cannot move in the circumferential direction and can roll on the spot about the radial direction, the same effect as that of the above-described embodiment can be obtained. be able to.
It should be noted that the rolling around the radial direction does not necessarily mean that the axis does not completely coincide with the radial direction, and also includes that the rolling element is rolling along the circumferential direction.

1,201,301 ... Wave gear mechanism (reduction mechanism), 3,203 ... Fixed gear (first gear), 4,204 ... Flexible gear (second gear), 4a ... Flat surface part (second flat surface part) , 5,205,305 ... Pressing part, 9 ... Fixed gear body, 9a ... Flat part (first flat part), 10 ... Cylindrical roller (first tooth part, rolling element), 11 ... Cage, 13 ... Output shaft , 14 ... tooth part (second tooth part), 14a ... tooth bottom, 14b ... tooth tip, 15,215 ... support shaft, 16,216 ... roller, 27 ... flexible gear body, 27a ... flat surface part (second) Flat part), 29 ... Tooth part (second tooth part), 40 ... Cam, 41 ... Disc body (plate part), 42 ... Convex part, 43 ... Thrust roller bearing, 48 ... Resistance reduction layer, 203a ... Flat part (1st plane part), C ... Central axis (axis)

Claims (11)

A first plane portion orthogonal to the axis direction, and a first gear having a plurality of first tooth portions provided on the first plane portion and arranged in an annular shape around the axis line.
It has a second plane portion that faces the first plane portion in the axial direction and elastically deforms in the axial direction, and a second tooth portion provided on the second plane portion and arranged in an annular shape around the axis. With the second gear
A pressing portion that rotates around the axis and presses the second flat surface portion toward the first flat surface portion to engage the second tooth portion with respect to the first tooth portion.
Equipped with
At least one of the first tooth portion and the second tooth portion is composed of a plurality of rolling elements that are meshed with the other.
The rolling element is a deceleration mechanism provided so as to be rollable about a radial direction orthogonal to the circumferential direction of the first gear and the second gear. One of the first tooth portion and the second tooth portion is composed of a plurality of rolling elements that are meshed with the other.
The deceleration mechanism according to claim 1, wherein the tooth bottom of either the first tooth portion or the second tooth portion is formed in an arc shape corresponding to the shape of the rolling element. The deceleration mechanism according to claim 2, wherein the tooth tip of either the first tooth portion or the second tooth portion is formed in an arc shape. The deceleration mechanism according to any one of claims 1 to 3, wherein the rolling element is provided on the first gear. The pressing part is
With the support shaft extending in the radial direction,
A roller that is rotatably supported by the support shaft and presses the second flat surface portion toward the first flat surface portion.
The deceleration mechanism according to any one of claims 1 to 4. The pressing portion includes a cam and
The cam
The plate part that rotates around the axis and the plate
A convex portion that protrudes from the plate portion toward the second gear and presses the second flat surface portion toward the first flat surface portion.
The deceleration mechanism according to any one of claims 1 to 4. The reduction mechanism according to claim 6, further comprising a thrust roller bearing provided between the second gear and the cam and provided in an annular shape around the axis. The deceleration according to claim 6 or 7, further comprising a resistance reducing layer provided on at least one of the facing surfaces of the second gear and the convex portion to reduce the contact resistance between the second gear and the convex portion. mechanism. The deceleration mechanism according to any one of claims 1 to 8, wherein the second gear has a shaft provided so as to project coaxially with the axis from the second flat surface portion. A first plane portion orthogonal to the axis direction, and a first gear having a plurality of first tooth portions provided on the first plane portion and arranged in an annular shape around the axis line.
It has a second plane portion that faces the first plane portion in the axial direction and elastically deforms in the axial direction, and a second tooth portion provided on the second plane portion and arranged in an annular shape around the axis. With the second gear
A pressing portion that rotates around the axis and presses the second flat surface portion toward the first flat surface portion to engage the second tooth portion with respect to the first tooth portion.
Equipped with
The first tooth portion is restricted from moving in the circumferential direction with respect to the first plane portion by a cage, and the first tooth portion is provided so as to be rotatable about a radial direction orthogonal to the circumferential direction of the first plane portion. And
The tooth bottom of the second tooth portion is formed in an arc shape corresponding to the shape of the cylindrical roller.
The tooth tip of the second tooth portion is formed in an arc shape.
The pressing part is
With the support shaft extending in the radial direction,
A roller rotatably supported by the support shaft and
Deceleration mechanism with. A first plane portion orthogonal to the axis direction, and a first gear having a plurality of first tooth portions provided on the first plane portion and arranged in an annular shape around the axis line.
It has a second plane portion that faces the first plane portion in the axial direction and elastically deforms in the axial direction, and a second tooth portion provided on the second plane portion and arranged in an annular shape around the axis. With the second gear
A pressing portion that rotates around the axis and presses the second flat surface portion toward the first flat surface portion to engage the second tooth portion with respect to the first tooth portion.
A thrust roller bearing provided between the second gear and the pressing portion and provided in an annular shape around the axis.
Equipped with
The first tooth portion is restricted from moving in the circumferential direction with respect to the first plane portion by a cage, and the first tooth portion is provided so as to be rotatable about a radial direction orthogonal to the circumferential direction of the first plane portion. And
The tooth bottom of the second tooth portion is formed in an arc shape corresponding to the shape of the cylindrical roller.
The tooth tip of the second tooth portion is formed in an arc shape.
The pressing portion is a cam and
The cam
The plate part that rotates around the axis and the plate
A convex portion protruding from the plate portion toward the second gear,
Deceleration mechanism with.

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