Torque transmission mechanism

Abstract

During the operation of the torque transmission mechanism, a shear load was applied to the internal pin responsible for torque transmission, which posed a risk of the internal pin breaking. [Solution] The torque transmission mechanism comprises a first member 130 having a cylindrical shape, configured to be rotatable around a rotation axis AX, and provided with a zigzag-shaped first groove 132; a second member 150 having an annular shape surrounding the first member 130, configured to be rotatable around a rotation axis AX, and provided with a zigzag-shaped second groove 152; a spherical first rolling member disposed within the first groove 132 and the second groove 152; and a first restricting member 190 that allows the first rolling member 170 to move along the rotation axis AX and restricts the first rolling member 170 to move around the rotation axis AX, wherein the first restricting member 190 comprises a columnar member 211 having a central axis BX, and the columnar member 211 has a cylindrical shape and is configured to be rotatable around the central axis BX.

Description

Technical Field

[0001] The present invention relates to a torque transmission mechanism.

Background Art

[0002] Regarding torque transmission mechanisms, Patent Document 1 discloses an eccentric swing type reduction mechanism. In the reduction mechanism of Patent Document 1, torque transmission is realized by transmitting the rotation component of the external gear to the carrier body via an inner pin.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] <unk> In the technology of Patent Document 1, during the operation of the mechanism, a shear load is generated on the inner pin responsible for torque transmission, which may cause the inner pin to break.

Means for Solving the Problems

[0005] The torque transmission mechanism comprises a first member having a cylindrical shape and configured to be rotatable around a rotation axis, the first member having an outer circumferential surface provided with a zigzag-shaped first groove extending around the rotation axis; a second member having an annular shape surrounding the first member and configured to be rotatable around the rotation axis, the second member having an inner circumferential surface provided with a zigzag-shaped second groove extending around the rotation axis; one or more spherical first rolling members disposed within the first groove and the second groove and configured to roll within the first groove and the second groove; and a first restricting member disposed between the first member and the second member, allowing the first rolling members to move along the rotation axis and restricting the first rolling members to move around the rotation axis, wherein the first restricting member comprises a columnar member having a central axis along the rotation axis, the columnar member restricting the movement of the first rolling members, and the columnar member having a cylindrical shape and configured to be rotatable around the central axis. [Brief explanation of the drawing]

[0006] [Figure 1] A perspective view showing the schematic configuration of the torque transmission mechanism in the first embodiment. [Figure 2] An exploded perspective view showing the schematic configuration of the torque transmission mechanism in the first embodiment. [Figure 3] Section III-III in Figure 1. [Figure 4] Section IV-IV of Figure 1. [Figure 5] A first explanatory diagram of the torque transmission mechanism in the first embodiment. [Figure 6] A second explanatory diagram of the torque transmission mechanism in the first embodiment. [Figure 7] A schematic cross-sectional view showing the general configuration of the torque transmission mechanism in the second embodiment. [Figure 8] Figure 7 shows the VIII-VIII section. [Figure 9] A schematic cross-sectional view showing the general configuration of the torque transmission mechanism in the third embodiment. [Figure 10] A schematic cross-sectional view showing the general configuration of the torque transmission mechanism in the fourth embodiment. [Figure 11] Perspective view showing the schematic configuration of the torque transmission mechanism in the fifth embodiment. [Figure 12] Exploded perspective view showing the schematic configuration of the torque transmission mechanism in the fifth embodiment. [Figure 13] Cross-sectional view taken along XIII-XIII of FIG. 11. [Figure 14] Cross-sectional view taken along XIV-XIV of FIG. 11. [Figure 15] Cross-sectional view schematically showing the torque transmission mechanism in the sixth embodiment. [Figure 16] Cross-sectional view schematically showing the torque transmission mechanism in the sixth embodiment. [Figure 17] Cross-sectional view schematically showing the torque transmission mechanism in the sixth embodiment. [Figure 18] Cross-sectional view schematically showing the torque transmission mechanism in the sixth embodiment. [Figure 19] Cross-sectional view schematically showing the torque transmission mechanism in the sixth embodiment. [Figure 20] Cross-sectional view schematically showing the torque transmission mechanism in the sixth embodiment. [Figure 21] Cross-sectional view schematically showing the torque transmission mechanism in the sixth embodiment. [Figure 22] Cross-sectional view schematically showing the torque transmission mechanism in the seventh embodiment. [Figure 23] Cross-sectional view schematically showing the torque transmission mechanism in the seventh embodiment. [Figure 24] Explanatory view of the first example of the torque transmission mechanism in other embodiments. [Figure 25] Explanatory view of the second example of the torque transmission mechanism in other embodiments. [Figure 26] Explanatory view of the third example of the torque transmission mechanism in other embodiments.

MODE FOR CARRYING OUT THE INVENTION

[0007] A. First Embodiment: FIG. 1 is a perspective view showing a schematic configuration of a torque transmission mechanism 100 in the first embodiment. FIG. 2 is an exploded perspective view showing the schematic configuration of the torque transmission mechanism 100. In FIG. 1, arrows indicating the X, Y, and Z directions orthogonal to each other are shown. The X direction and the Y direction are directions parallel to the horizontal plane, and the Z direction is a direction along the vertically upward direction. The arrows indicating the X, Y, and Z directions are also appropriately shown in other figures so that the illustrated directions correspond to those in FIG. 1. In the following description, when specifying the direction, the direction indicated by the arrow in each figure is defined as “+” and the opposite direction is defined as “−”, and positive and negative signs are used together in the direction notation. Hereinafter, the +Z direction is also referred to as “up” and the −Z direction is also referred to as “down”.

[0008] In the present embodiment, the torque transmission mechanism 100 is configured as a speed reduction device. As shown in FIGS. 1 and 2, the torque transmission mechanism 100 includes a first member 130, a second member 150, one or more first rolling members 170, and a first restricting member 190. Further, the torque transmission mechanism 100 in the present embodiment includes a first bearing portion 201 and a second bearing portion 202.

[0009] The torque transmission mechanism 100 in the present embodiment has a cylindrical shape as a whole. The torque transmission mechanism 100 is arranged such that the rotation axis AX of the torque transmission mechanism 100 extends along the Z direction. In the present embodiment, the rotation axis AX corresponds to the rotation axis of the first member 130 and the rotation axis of the second member 150. In the present disclosure, the “cylindrical shape” includes a solid cylindrical shape and a hollow cylindrical shape. Hereinafter, the direction along the rotation axis AX is also referred to as the rotation axis AX direction.

[0010] The circumferential direction DC of the torque transmission mechanism 100 corresponds to the circumferential direction of the first member 130 and the circumferential direction of the second member 150. In the present disclosure, the circumferential direction DC is defined as the counterclockwise direction when the torque transmission mechanism 100 is viewed from the +Z direction side. Hereinafter, unless otherwise specified, “counterclockwise” means the counterclockwise direction when the torque transmission mechanism 100 is viewed from the +Z direction side. The same applies to “clockwise”.

[0011] The first member 130 has a cylindrical shape. More specifically, the first member 130 has a hollow cylindrical shape. The first member 130 is positioned such that its axial direction is aligned with the Z direction. In this embodiment, the first member 130 is positioned furthest inward in the horizontal direction among the various parts of the torque transmission mechanism 100. The first member 130 is configured to be rotatable around the rotation axis AX of the torque transmission mechanism 100. As shown in Figure 2, the first member 130 has an outer circumferential surface 131. The outer circumferential surface 131 is provided with a first groove 132. The first groove 132 has a zigzag shape that extends around the rotation axis AX on the outer circumferential surface 131 and completes one revolution. In this specification, "zigzag shape" means a shape that extends in a direction perpendicular to a certain direction while reciprocating one or more times in that direction. That is, the zigzag shape has one or more turning points. The zigzag-shaped turning points may be pointed or rounded. Details of the first groove 132 will be described later.

[0012] As shown in Figures 1 and 2, the second member 150 has an annular shape that surrounds the first member 130. That is, the inner diameter of the second member 150 is larger than the outer diameter of the first member 130. The second member 150 is positioned such that its axial direction is along the Z direction. In this embodiment, the second member 150 is positioned as the outermost part of the torque transmission mechanism 100 in the horizontal direction. The second member 150 is configured to be rotatable around the rotation axis AX. As shown in Figure 2, the second member 150 has an inner circumferential surface 151. A second groove 152 is provided on the inner circumferential surface 151. The second groove 152 has a zigzag shape that extends around the rotation axis AX on the inner circumferential surface 151 and completes a full rotation. Details of the second groove 152 will be described later.

[0013] Figure 3 is a cross-sectional view taken along line III-III of Figure 1. Figure 4 is a cross-sectional view taken along line IV-IV of Figure 1. As shown in Figures 3 and 4, the first rolling member 170 is positioned between the first member 130 and the second member 150, within the first groove 132 and the second groove 152. The first rolling member 170 is configured to roll within the first groove 132 and the second groove 152. Specifically, the first rolling member 170 rolls within the first groove 132 and the second groove 152 such that it is positioned where the first groove 132 and the second groove 152 intersect when viewed along the radial direction of the torque transmission mechanism 100. As the first rolling member 170 rolls within the first groove 132, the first rolling member 170 and the first member 130 move relative to each other. Furthermore, as the first rolling member 170 rolls within the second groove 152, the first rolling member 170 and the second member 150 move relative to each other. In this embodiment, the first rolling member 170 has a spherical shape. The first rolling member 170 is, for example, made of a so-called steel ball, and is made of stainless steel or iron. As will be described later, the first rolling member 170 transmits torque between the first member 130 and the second member 150.

[0014] In this embodiment, the first rolling member 170 includes rolling member 170A, rolling member 170B, rolling member 170C, rolling member 170D, and rolling member 170E. When the rolling members from 170A to 170E are not distinguished, each is simply referred to as the first rolling member 170. The rolling members 170A, 170B, 170C, 170D, and 170E are arranged in this order in the circumferential direction DC when the torque transmission mechanism 100 is viewed from the +Z direction side.

[0015] As shown in Figures 3 and 4, the first restricting member 190 is positioned between the first member 130 and the second member 150. In this embodiment, the first restricting member 190 has a hollow cylindrical shape overall. The first restricting member 190 is positioned such that its axial direction is aligned with the Z direction.

[0016] The first restricting member 190 has a main body portion 191, a first flange portion 192, and a second flange portion 193. The main body portion 191 is the part of the first restricting member 190 that is positioned within the ring of the second member 150. The first flange portion 192 is an annular flange portion that constitutes the lower end of the first restricting member 190. The second flange portion 193 is an annular flange portion that constitutes the upper end of the first restricting member 190. As shown in Figures 1 and 4, the first flange portion 192 is not positioned within the ring of the second member 150, but is positioned below the lower end of the first member 130 and the lower end of the second member 150. Similarly, the second flange portion 193 is positioned above the upper end of the first member 130 and the upper end of the second member 150. In this embodiment, the first flange portion 192 is integrally formed with the main body portion 191. The second flange portion 193 is configured as a separate cap from the main body portion 191 and is fixed to the main body portion 191 via a bolt 194. The outer diameter of the main body portion 191 is smaller than the inner diameter of the second member 150. On the other hand, the outer diameters of the first flange portion 192 and the second flange portion 193 are larger than the inner diameter of the second member 150. The inner diameter of the main body portion 191 is larger than the outer diameter of the first member 130. On the other hand, the inner diameters of the first flange portion 192 and the second flange portion 193 are smaller than the outer diameter of the first member 130. The inner diameter of the first flange portion 192 is approximately the same as the inner diameter of the second flange portion 193. The outer diameter of the first flange portion 192 is approximately the same as the outer diameter of the second flange portion 193.

[0017] As shown in Figures 2 to 4, the main body portion 191 has slit portions 195. In this embodiment, the main body portion 191 has five slit portions 195. The slit portions 195 are configured as openings that extend along the rotation axis AX, that is, along the Z direction. Between the openings of each slit portion 195, the wall portions 196 of the main body portion 191 are arranged. The wall portions 196 correspond to the walls in the circumferential direction DC among the walls that demarcate the openings of the slit portions 195. As shown in Figures 2 and 4, in this embodiment, the lower end of the opening of the slit portion 195 is demarcated by the first flange portion 192. Also, as shown in Figure 4, the upper end of the opening of the slit portion 195 is demarcated by the second flange portion 193. The opening width of the slit portion 195 in the circumferential direction DC is slightly larger than the diameter of the first rolling member 170. Also, the opening length of the slit portion 195 in the Z direction is greater than the opening width of the slit portion 195.

[0018] The first restricting member 190 has a first restricting portion 199. The first restricting portion 199 allows the first rolling member 170 to move along the rotation axis AX, i.e., move in the Z direction. On the other hand, the first restricting portion 199 restricts the movement of the first rolling member 170 about the rotation axis AX. In this embodiment, the first restricting portion 199 includes restricting portions 199A, 199B, 199C, 199D, and 199E. Hereinafter, when restricting portions 199A to 199E are not distinguished, each will simply be referred to as the first restricting portion 199. The first restricting portion 199 will also simply be referred to as the restricting portion.

[0019] Specifically, in this embodiment, the first restricting portion 199 has the slit portion 195 described above, and the slit portion 195 enables both permission and restriction of the movement of the first rolling member 170. For example, the rolling member 170A is placed within the slit portion 195 of the restricting portion 199A. As a result, movement of the rolling member 170A in the Z direction along the slit portion 195 is permitted. On the other hand, movement of the rolling member 170A around the rotation axis AX is restricted by the wall portion 196 that partitions the slit portion 195. Similarly, rolling members 170B to 170E are placed within each slit portion 195 of the restricting portions 199B to 199E, respectively. It is preferable that the number of first rolling members 170 be determined, for example, taking into account the strength of the first restricting member 190. Specifically, the more first rolling members 170 there are, the larger the total opening area of ​​each slit portion 195 in the first restricting member 190 becomes, which may reduce the strength of the first restricting member 190. It is preferable that the number of first rolling members 170 be set to a number small enough to suppress such a reduction in strength.

[0020] The first bearing portion 201 is positioned between the first member 130 and the first regulating member 190. The first bearing portion 201 holds the first member 130 so that it can rotate around the rotation axis AX relative to the first regulating member 190. The first bearing portion 201 is composed of various bearings, such as ball bearings and needle bearings. In this embodiment, two first bearing portions 201 are provided. Each first bearing portion 201 is press-fitted and fixed to the outside of the upper end and the outside of the lower end of the first member 130, respectively, and pivotally supports the upper and lower ends of the first member 130. The first bearing portion 201 on the lower end side of the first member 130 is positioned inside the main body portion 191 so as to be in contact with the upper surface of the first flange portion 192. The first bearing portion 201 on the upper end side of the first member 130 is positioned inside the main body portion 191 so as to be in contact with the lower surface of the second flange portion 193. As a result, the movement of the first member 130 in the Z direction relative to the first restricting member 190 is restricted, while the first member 130 is held rotatably relative to the first restricting member 190.

[0021] The second bearing portion 202 is positioned between the second member 150 and the first regulating member 190. The second bearing portion 202 holds the second member 150 so that it can rotate around the rotation axis AX relative to the first regulating member 190. The second bearing portion 202 is composed of various bearings, for example, similar to the first bearing portion 201. In this embodiment, two second bearing portions 202 are provided. Each second bearing portion 202 is press-fitted and fixed to the inside of the upper end and the inside of the lower end of the second member 150, respectively, and pivotally supports the upper and lower ends of the second member 150. The second bearing portion 202 on the lower end side of the second member 150 is positioned on the outside of the main body portion 191 so as to be in contact with the upper surface of the first flange portion 192. The second bearing portion 202 on the upper end side of the second member 150 is positioned on the outside of the main body portion 191 so as to be in contact with the lower surface of the second flange portion 193. As a result, the movement of the second member 150 in the Z direction relative to the first restricting member 190 is restricted, and the second member 150 is held rotatably relative to the first restricting member 190.

[0022] Figure 5 is a first explanatory diagram of the torque transmission mechanism 100. Figure 5 shows the outer circumferential surface 131t and the inner circumferential surface 151t. The outer circumferential surface 131t corresponds to the unfolded outer circumferential surface 131. The inner circumferential surface 151t corresponds to the unfolded inner circumferential surface 151. Figure 5 shows the outer circumferential surface 131t and the inner circumferential surface 151t superimposed. In addition, in Figure 5, each first restricting portion 199 is schematically shown by dashed lines. In addition, in Figure 5, each first rolling member 170 is schematically shown by hatching.

[0023] Figure 5 shows the angles θ at the outer circumferential surface 131 and the inner circumferential surface 151. The angle θ increases as the circumferential direction DC progresses. The 0-degree angular position A0 and the 360-degree angular position A360 shown in Figure 5 are the same position. In this embodiment, the restricting portion 199A is located at angular position A0. In Figure 5, rolling members 170A and restricting portions 199A are shown near angular position A0 and near angular position A360, respectively, to facilitate understanding of the technology. However, in reality, there is only one rolling member 170A and one restricting portion 199A.

[0024] In Figure 5, the first groove 132 is shown by a thick line. The first groove 132 has a closed ring shape that encircles the outer surface 131 along the circumferential direction DC. Overall, the first groove 132 has a periodic wave shape that moves along the circumferential direction DC while reciprocating along the outer surface 131 in the Z direction. That is, when the first groove 132 is considered as a wave, the direction of propagation of the first groove 132 is along the circumferential direction DC, and the direction of vibration of the first groove 132 is in the Z direction. Specifically, the first groove 132 has a triangular wave shape. The first groove 132 has one period. That is, the first groove 132 has one peak 132m and one trough 132v. The peak 132m and trough 132v have a pointed shape. Note that there may be multiple peaks and troughs. In this case, the position of each peak 132m in the Z direction is approximately the same. Furthermore, the positions of each trough 132v in the Z direction are approximately the same. That is, when the first groove 132 is considered as a wave, the amplitude of the first groove 132 is approximately constant. Each peak and each trough corresponds to the turning point of the zigzag shape described above. In this embodiment, the peaks are located on the +Z direction side of the troughs. In other embodiments, the positional relationship between the peaks and troughs may be reversed.

[0025] The second groove 152 has a closed ring shape that encircles the inner circumferential surface 151 along the circumferential direction DC. Overall, the second groove 152 has a periodic wave shape that moves along the circumferential direction DC while reciprocating along the inner circumferential surface 151 in the Z direction. That is, when the second groove 152 is considered as a wave, the direction of propagation of the second groove 152 is along the circumferential direction DC, and the direction of vibration of the second groove 152 is in the Z direction. Specifically, the second groove 152 has a triangular wave shape. The second groove 152 has a different period than the first groove 132. Specifically, the second groove 152 has 12 periods. That is, the second groove 152 has 12 peaks 152m and 12 troughs 152v. The peaks 152m and troughs 152v have a pointed shape. The positions of each peak 152m in the Z direction are approximately the same, and are approximately the same as the positions of each peak 132m in the Z direction. Similarly, the positions of each valley 152v in the Z direction are approximately the same, and are approximately the same as the positions of each valley 132v in the Z direction. In other words, when the second groove 152 is considered as a wave, the amplitude of the second groove 152 is approximately constant and is approximately the same as the amplitude of the first groove 132.

[0026] In this embodiment, in the torque transmission mechanism 100, either the first member 130 or the second member 150 is used as the input shaft, and the other is used as the output shaft. The operation of the torque transmission mechanism 100 when the first member 130 is used as the input shaft will be described below.

[0027] Figure 6 is a second explanatory diagram of the torque transmission mechanism 100. Figure 6 shows the state in which the first member 130, which acts as the input shaft, has rotated circumferentially DC about the rotation axis AX by a rotation angle θ1 from the state in Figure 5. In the example of Figure 6, the rotation angle θ1 is 60 degrees.

[0028] As shown in Figure 6, as the first member 130 rotates around the rotation axis AX, each first rolling member 170 rolls within the first groove 132 and the second groove 152. Specifically, the rotation of the first member 130 causes the first rolling member 170 to roll along a path Pt1 within the first groove 132. The path Pt1 is a path whose length in the circumferential direction DC corresponds to the rotation angle θ1. Specifically, the path Pt1 is a path in the first groove 132 whose starting point S1 is the position of the first rolling member 170 before the rotation of the first member 130 begins, and whose ending point E1 is the position advanced in the circumferential direction DC from the starting point by an amount corresponding to the rotation angle θ1. In Figure 6, as an example of the path Pt1, the path Pt1 for rolling member 170A is shown by dot hatching. As the first rolling member 170 rolls along path Pt1, its movement around the rotation axis AX is restricted, causing it to move only in the Z direction according to the first groove 132. As a result, the circumferential position DC of the first rolling member 170 remains unchanged, while its position in the Z direction changes according to the position of path Pt1 in the Z direction. Furthermore, as the first rolling member 170 rolls along path Pt2 in the second groove 152 while moving in the Z direction, it transmits torque to the second member 150 via the second groove 152, causing the second member 150 to rotate around the rotation axis AX. Path Pt2 is a path where the change in the position of the first rolling member 170 in the rotation axis AX direction when passing through path Pt2 is the same as the change in the position of the first rolling member 170 in the rotation axis AX direction when passing through path Pt1. In Figure 6, as an example of a path Pt2, the path Pt2 for the rolling member 170A is shown by dotted hatching. As a result, the second member 150 rotates around the rotation axis AX by a rotation angle θ2, which corresponds to the length of the path Pt2 in the circumferential direction DC, i.e., the length of the path Pt2 in the circumferential direction DC between the starting point S2 and the ending point E2. The ratio of the rotation angle θ2 to the rotation angle θ1 corresponds to the ratio of the period T1 of the first groove 132 to the period T2 of the second groove 152. In other words, the reduction ratio RR1a in this case corresponds to the value obtained by dividing the period T1 by the period T2.Furthermore, as shown by the white arrows in Figure 6, the first rolling member 170, such as the rolling member 170A, can also be described as moving the first groove 132 and the second groove 152 in the opposite direction to the rotational direction of the first member 130 and the second member 150, relative to the first member 130 and the second member 150.

[0029] The operation of the torque transmission mechanism 100 when the second member 150 is used as the input shaft is substantially the same as the operation of the torque transmission mechanism 100 when the first member 130 is used as the input shaft. In this case, the first rolling member 170 rolls within the first groove 132 due to the rotation of the second member 150, thereby transmitting torque to the first member 130 via the first groove 132. In this case, the reduction ratio RR1b corresponds to the value obtained by dividing the period T2 by the period T1. That is, in this case, the rotation input to the torque transmission mechanism 100 via the second member 150 is accelerated and output via the first member 130.

[0030] As shown in Figure 5, each first rolling member 170 is positioned at the intersection point CP where the first groove 132 and the second groove 152 intersect when viewed along the radial direction DR. The intersection point CP includes the first intersection point CP1, the second intersection point CP2, the third intersection point CP3, and the fourth intersection point CP4. The first intersection point CP1 is the position where the first positive portion P1 and the second positive portion P2 intersect. The first positive portion P1 is the portion of the first groove 132 that extends from the valley portion 132v toward the peak portion 132m in the forward direction of the circumferential direction DC. The second positive portion P2 is the portion of the second groove 152 that extends from the valley portion 152v toward the peak portion 152m in the forward direction of the circumferential direction DC. The second intersection point CP2 is the position where the first negative portion N1 and the second negative portion N2 intersect. The first negative portion N1 is the portion of the first groove 132 that extends from the peak 132m toward the valley 132v in the forward direction of the circumferential DC. The second negative portion N2 is the portion of the second groove 152 that extends from the peak 152m toward the valley 152v in the forward direction of the circumferential DC. The third intersection point CP3 is the position where the first positive portion P1 and the second negative portion N2 intersect. The fourth intersection point CP4 is the position where the first negative portion N1 and the second positive portion P2 intersect. Note that both the first positive portion P1 and the first negative portion N1 include the peaks of the peak 132m and the valley 132v. Also, both the second positive portion P2 and the second negative portion N2 include the peaks of the peak 152m and the valley 152v.

[0031] In this embodiment, each first rolling member 170 is positioned at either the first intersection point CP1 or the second intersection point CP2. As a result, the rotation directions of the first member 130 and the second member 150 coincide. In other embodiments, each first rolling member 170 may be positioned at either the third intersection point CP3 or the fourth intersection point CP4. In this case, the rotation directions of the first member 130 and the second member 150 are opposite to each other.

[0032] In the torque transmission mechanism 100 of this embodiment described above, the first rolling member 170, which is positioned in the first groove 132 of the first member 130 and the second groove 152 of the second member 150, is configured to be able to roll within the first groove 132 and the second groove 152. Within the first groove 132 and the second groove 152, movement of the first rolling member 170 along the rotation axis AX is permitted, while movement of the first rolling member 170 about the rotation axis AX is restricted. Therefore, torque can be transmitted between the first member 130 and the second member 150 without using a torque transmission pin.

[0033] Furthermore, in this embodiment, the number of peaks 132m and valleys 132v in the first groove 132 is different from the number of peaks 152m and valleys 152v in the second groove 152. According to this configuration, the rotational speed between the first member 130 and the second member 150 can be reduced according to the number of peaks 132m and valleys 132v in the first groove 132 and the number of peaks 152m and valleys 152v in the second groove 152. That is, the rotational speed between the first member 130 and the second member 150 can be reduced according to the difference between the period T1 of the first groove 132 and the period T2 of the second groove 152. In addition, in this embodiment, various reduction ratios can be achieved with a high degree of freedom by arbitrarily changing the combination of period T1 and period T2.

[0034] Furthermore, in this embodiment, the first rolling member 170 has a spherical shape. Therefore, the first rolling member 170 can roll more smoothly within the first groove 132 and the second groove 152. As a result, wear of the first member 130, the second member 150, the first rolling member 170, and the first regulating member 190 can be suppressed.

[0035] Furthermore, in this embodiment, the first rolling member 170 includes one rolling member 170A and another rolling member 170B. In this way, torque can be transmitted between the first member 130 and the second member 150 using the rolling members 170A and 170B. Therefore, compared to a configuration in which only the rolling member 170A is provided, for example, the load on each of the first rolling members 170 can be reduced.

[0036] Furthermore, as in this embodiment, the provision of multiple first rolling members 170 makes it easier to uniquely determine the rotation direction of the second member 150 relative to the first member 130, or the rotation direction of the first member 130 relative to the second member 150. Specifically, for example, if only a rolling member 170A is provided, when the rotation of the first member 130 as the input shaft causes the rolling member 170A to reach the peaks 152m or valleys 152v of the second groove 152, the rolling member 170A can advance within the second groove 152 in both directions of the circumferential direction DC. As a result, the second member 150 can rotate in both the forward and reverse directions of the circumferential direction DC, which can lead to a phenomenon where the second member 150 reciprocates in a closed space in the circumferential direction DC. This phenomenon is particularly likely to occur when the rotational speeds of the first member 130 and the second member 150 are low. This phenomenon can also occur when the second member 150 is used as an input shaft. On the other hand, if a rolling member 170B is provided in addition to the rolling member 170A, for example, when the rolling member 170A reaches the peak portion 152m or the valley portion 152v, the rolling member 170B can be positioned in a portion of the second groove 152 other than the peak portion 152m and the valley portion 152v. In this case, the direction of movement of the rolling member 170B within the second groove 152 is uniquely determined, and the direction of movement of the rolling member 170B within the second groove 152 and the rotation direction of the second member 150 are also uniquely determined.

[0037] Furthermore, in this embodiment, the first member 130 can be rotated more smoothly relative to the first regulating member 190 via the first bearing portion 201 positioned between the first member 130 and the first regulating member 190.

[0038] Furthermore, in this embodiment, the second member 150 can be rotated more smoothly relative to the first regulating member 190 via the second bearing portion 202 positioned between the second member 150 and the first regulating member 190.

[0039] Furthermore, in this embodiment, the first groove 132 and the second groove 152 each have a triangular wave shape. Therefore, at each position within the first groove 132 and at each position within the second groove 152, the amount of movement of the first rolling member 170 in the Z direction per unit rotation angle of the first member 130 and the second member 150 is substantially constant, so that the first member 130 can be rotated more stably relative to the second member 150, or the second member 150 can be rotated more stably relative to the first member 130. As a result, more stable deceleration can be achieved between the first member 130 and the second member 150. In addition, compared to the case where the first groove 132 and the second groove 152 have a zigzag shape with rounded peaks and valleys, such as a sinusoidal curve shape, the torque transmission efficiency at the peaks and valleys can be further improved. As a result, torque can be transmitted more efficiently between the first member 130 and the second member 150.

[0040] B. Second Embodiment: Figure 7 is a schematic cross-sectional view showing the general configuration of the torque transmission mechanism 100b in the second embodiment. Figure 8 is a cross-sectional view taken along line VIII-VIII of Figure 7. Figure 7 shows a cross-section of the torque transmission mechanism 100b along the X and Y directions. Figure 8 shows a cross-section of the torque transmission mechanism 100b along the X and Z directions. As shown in Figures 7 and 8, in this embodiment, unlike the first embodiment, a third groove 162 is provided on the outer circumferential surface 161 of the second member 150b. The torque transmission mechanism 100b further comprises a third member 230, one or more second rolling members 250, and a second regulating member 270. In this embodiment, the torque transmission mechanism 100b is the same as in the first embodiment unless otherwise specified. Note that Figures 7 and 8 show examples where the number of first rolling members 170 and the number of second rolling members 250 are each four. Furthermore, in Figures 7 and 8, the first groove 132, the second groove 152, and the third groove 162 are schematically shown by dashed lines. Also, in Figures 7 and 8, components such as the first bearing section 201 and the second bearing section 202 are omitted as appropriate.

[0041] The third groove 162 has a zigzag shape that extends around the rotation axis AX on the outer circumferential surface 161 and completes a full rotation. The third groove 162 is configured substantially the same as, for example, the first groove 132. In this embodiment, the third groove 162 has a closed ring shape that completes a full rotation in the circumferential direction DC on the outer circumferential surface 161. The third groove 162 as a whole has a periodic wave shape that moves along the circumferential direction DC while reciprocating along the rotation axis AX on the outer circumferential surface 161. Specifically, the third groove 162 has a triangular wave shape. The period T3 of the third groove 162 may be the same as or different from the periods T1 and T2. In this embodiment, the period T3 is 1. When the period T3 is 2 or more, the positions of each peak of the third groove 162 in the Z direction are substantially the same. Also, the positions of each trough of the third groove 162 in the Z direction are substantially the same.

[0042] As shown in Figure 7, the third member 230 has an annular shape that surrounds the second member 150b. That is, the inner diameter of the third member 230 is larger than the outer diameter of the second member 150b. In this embodiment, the third member 230 is positioned on the outermost side in the horizontal direction among the various parts of the torque transmission mechanism 100b. The third member 230 is configured to be rotatable around the rotation axis AX. As shown in Figures 7 and 8, the third member 230 has an inner circumferential surface 231. A fourth groove 232 is provided on the inner circumferential surface 231.

[0043] The fourth groove 232 has a zigzag shape that extends around the rotation axis AX on the inner circumferential surface 231 and completes a full rotation. The fourth groove 232 is configured substantially the same as, for example, the second groove 152. The fourth groove 232 has a closed ring shape that completes a full rotation in the circumferential direction DC on the inner circumferential surface 231. The fourth groove 232 as a whole has a periodic wave shape that moves along the circumferential direction DC while reciprocating along the rotation axis AX on the inner circumferential surface 231. Specifically, the fourth groove 232 has a triangular wave shape. The fourth groove 232 has a period T4 that is different from period T3. That is, the number of peaks and troughs of the third groove 162 is different from the number of peaks and troughs of the fourth groove 232. Period T4 may be the same as or different from periods T1 and T2. In this embodiment, the relationship between the magnitudes of period T4 and period T3 is the same as the relationship between the magnitudes of period T2 and period T1. Specifically, the period T4 in this embodiment is 12. The positions of each peak in the fourth groove 232 in the Z direction are approximately the same, and are approximately the same as the positions of each peak in the third groove 162 in the Z direction. Also, the positions of each valley in the fourth groove 232 in the Z direction are approximately the same, and are approximately the same as the positions of each valley in the third groove 162 in the Z direction.

[0044] The second rolling member 250 is configured substantially the same as the first rolling member 170, for example. The second rolling member 250 is positioned between the second member 150b and the third member 230, within the third groove 162 and the fourth groove 232. The second rolling member 250 is configured to roll within the third groove 162 and the fourth groove 232. Specifically, the second rolling member 250 rolls within the third groove 162 and the fourth groove 232 such that it is positioned where the third groove 162 and the fourth groove 232 intersect when viewed along the radial direction of the torque transmission mechanism 100b. In this embodiment, the second rolling member 250 has a spherical shape, similar to the first rolling member 170. The second rolling member 250 transmits torque between the second member 150b and the third member 230.

[0045] The second restricting member 270 is configured substantially the same as the first restricting member 190, for example. In this embodiment, the second restricting member 270 has a hollow cylindrical shape as a whole. The second restricting member 270 is positioned between the second member 150b and the third member 230. The second restricting member 270 allows the second rolling member 250 to move along the rotation axis AX and restricts the movement of the second rolling member 250 about the rotation axis AX. For example, bearing portions substantially the same as the first bearing portion 201 and the second bearing portion 202 may be positioned between the second restricting member 270 and the second member 150b, and between the second restricting member 270 and the third member 230. That is, such bearing portions hold the second member 150b or the third member 230 so that it can rotate around the rotation axis AX relative to the second restricting member 270.

[0046] In this embodiment, similar to the first embodiment, reduction is achieved between the first member 130 and the second member 150b via the first rolling member 170. Furthermore, in this embodiment, reduction is achieved between the second member 150b and the third member 230 via the second rolling member 250. The behavior of the third member 230 with respect to the second member 150b is substantially the same as the behavior of the second member 150b with respect to the first member 130. For example, when the first member 130 is used as the input shaft, a reduction ratio RR1a is achieved between the first member 130 and the second member 150b, and a reduction ratio RR2a is achieved between the second member 150b and the third member 230. The reduction ratio RR2a corresponds to the value obtained by dividing the period T3 by the period T4. As a result, a reduction ratio RR3a is achieved between the first member 130 as the input shaft and the third member 230 as the output shaft. The reduction ratio RR3a corresponds to the product of the reduction ratio RR1a and the reduction ratio RR2a. Furthermore, when the third member 230 is used as the input shaft, a reduction ratio RR2b is achieved between the third member 230 and the second member 150b, and a reduction ratio RR1b is achieved between the second member 150b and the first member 130. The reduction ratio RR2b corresponds to the value obtained by dividing the period T4 by the period T3. As a result, a reduction ratio RR3b is achieved between the third member 230 as the input shaft and the first member 130 as the output shaft. The reduction ratio RR3b corresponds to the product of the reduction ratio RR1b and the reduction ratio RR2b. In other words, in this case, the rotation input to the torque transmission mechanism 100b is accelerated and output.

[0047] According to the torque transmission mechanism 100b in the second embodiment described above, the second rolling member 250, which is positioned in a third groove 162 provided on the outer circumferential surface 161 of the second member 150b and in a fourth groove 232 provided on the inner circumferential surface 231 of the third member 230 surrounding the second member 150b, is configured to roll within the third groove 162 and the fourth groove 232. Movement of the second rolling member 250 along the rotation axis AX is permitted, while movement of the second rolling member 250 about the rotation axis AX is restricted. Furthermore, the number of peaks and valleys in the third groove 162 and the number of peaks and valleys in the fourth groove 232 are different. In this way, the rotational speed can be gradually reduced between the first member 130 and the second member 150b, and between the second member 150b and the third member 230. Therefore, for example, a higher reduction ratio can be achieved without excessively increasing the period of the second groove 152 or the fourth groove 232. As a result, for example, the enlargement of the second member 150b and the third member 230 due to an increase in the period of the second groove 152 or the fourth groove 232 can be suppressed, so a higher reduction ratio can be achieved while making the torque transmission mechanism 100b more space-saving. Also, for example, the excessive miniaturization of the first rolling member 170 and the second rolling member 250 due to an increase in the period of the second groove 152 or the fourth groove 232 can be suppressed, so a higher reduction ratio can be achieved while suppressing a decrease in the durability of the torque transmission mechanism 100b. In other embodiments, for example, a fourth member 330 may be provided outside the third member 230 to achieve further stepwise reduction.

[0048] C. Third Embodiment: Figure 9 is a schematic cross-sectional view showing the general configuration of the torque transmission mechanism 100c in the third embodiment. Similar to Figure 8, Figure 9 shows cross-sections of the torque transmission mechanism 100c along the X and Z directions. In this embodiment, unlike the first embodiment, the outer circumferential surface 131c of the first member 130c is provided with a first corresponding groove 139 along with a first groove 132. The inner circumferential surface 151c of the second member 150c is provided with a second corresponding groove 159 along with a second groove 152. One or more third rolling members 280 are arranged within the first corresponding groove 139 and the second corresponding groove 159. The first regulating member 190 also has a second regulating portion 205 along with a first regulating portion 199. In this embodiment, the torque transmission mechanism 100c is the same as in the first embodiment unless otherwise specified.

[0049] The first corresponding groove 139 is arranged alongside the first groove 132 in the Z direction. In this embodiment, the first corresponding groove 139 is located on the +Z side of the first groove 132. The first corresponding groove 139 is a groove corresponding to the first groove 132 and has a zigzag shape corresponding to the first groove 132. Specifically, the first corresponding groove 139 has the same period as the first groove 132. That is, the first corresponding groove 139 has a periodic wave shape with the same number of peaks 139m and troughs 139v as the first groove 132m and troughs 132v. In this embodiment, the first groove 132 and the first corresponding groove 139 are arranged such that the peaks 132m of the first groove 132 and the troughs 139v of the first corresponding groove 139 face each other. In addition, the first member 130c may be constructed by separately forming the portion of the first member 130c that has the first groove 132 and the portion that has the first corresponding groove 139, and then fixing the two stacked portions together.

[0050] The second corresponding groove 159 is arranged alongside the second groove 152 in the Z direction. In this embodiment, the second corresponding groove 159 is located on the +Z side of the second groove 152. The second corresponding groove 159 is a groove corresponding to the second groove 152 and has a zigzag shape corresponding to the second groove 152. Specifically, the second corresponding groove 159 has the same period as the second groove 152. That is, the second corresponding groove 159 has a periodic wave shape with the same number of peaks 159m and troughs 159v as the second groove 152m and troughs 152v. Furthermore, the number of peaks 139m and troughs 139v in the first corresponding groove 139 is different from the number of peaks 159m and troughs 159v in the second corresponding groove 159. In this embodiment, the second groove 152 and the second corresponding groove 159 are arranged such that the peak portion 152m of the second groove 152 and the valley portion 159v of the second corresponding groove 159 face each other. The second member 150c may be constructed in substantially the same manner as the first member 130c, for example, with the portion where the second groove 152 is provided and the portion where the second corresponding groove 159 is provided being separate components.

[0051] The third rolling member 280 is configured to roll within the first corresponding groove 139 and the second corresponding groove 159. The third rolling member 280 is configured substantially the same as, for example, the first rolling member 170. The third rolling member 280 transmits torque between the first member 130 and the second member 150 substantially the same as the first rolling member 170. The second restricting section 205 allows the third rolling member 280 to move along the rotation axis AX and restricts the movement of the third rolling member 280 about the rotation axis AX. The second restricting section 205 is configured substantially the same as, for example, the first restricting section 199. Specifically, in this embodiment, the first restricting member 190 is provided with a slit portion 195c extending in the Z direction from the first groove 132 and the second groove 152 to the first corresponding groove 139 and the second groove 152, and the slit portion 195c enables the permitting and restricting of the movement of the first rolling member 170 and the third rolling member 280. In other embodiments, for example, the first restricting portion 199 and the second restricting portion 205 may each have separate slit portions, and the permitting and restricting of the movement of the first rolling member 170 and the third rolling member 280 may be achieved by each slit portion.

[0052] In this embodiment, at least one first rolling member 170 is configured to be located at the peak 132m of the first groove 132 when at least one third rolling member 280 is located at the valley 139v of the first corresponding groove 139. Also, at least one first rolling member 170 is configured to be located at the peak 152m of the second groove 152 when at least one third rolling member 280 is located at the valley 159v of the second corresponding groove 159. Figure 9 shows that when one rolling member 170p included in the first rolling member 170 is located at the peaks 132m and 152m, one rolling member 280p included in the third rolling member 280 is located at the valleys 139v and 159v. Furthermore, it is shown that when one rolling member 170q included in the first rolling member 170 is located in the valleys 132v and 152v, one rolling member 280q included in the third rolling member 280 is located in the peaks 139m and 159m. Although not shown in the illustration, when the rolling member 170p is located in the valleys 132v and 152v, the rolling member 280p is located in the peaks 139m and 159m. Similarly, when the rolling member 170q is located in the peaks 132m and 152m, the rolling member 280q is located in the valleys 139v and 159v.

[0053] In the torque transmission mechanism 100c of the third embodiment described above, the third rolling member 280, which is positioned in a first corresponding groove 139 provided on the outer circumferential surface 131c of the first member 130c and in a second corresponding groove 159 provided on the inner circumferential surface 151c of the second member 150c, is configured to be able to roll within the first corresponding groove 139 and the second corresponding groove 159. Movement of the third rolling member 280 along the rotation axis AX is permitted, while movement of the third rolling member 280 about the rotation axis AX is restricted. In this way, torque can be transmitted between the first member 130 and the second member 150 using the first rolling member 170 and the third rolling member 280. Therefore, the load on each rolling member can be reduced. In other embodiments, for example, the first member 130 may be provided with two or more first corresponding grooves 139, and the second member 150 may be provided with two or more second corresponding grooves 159.

[0054] Furthermore, in this embodiment, when the rolling member 170p is located at the peaks 132m and 152m, the rolling member 280p is located at the valleys 139v and 159v. This allows the first rolling member 170 and the third rolling member 280 to move in opposite directions in the direction of the rotation axis AX, thereby suppressing the oscillation of the torque transmission mechanism 100c in the direction of the rotation axis AX caused by the movement of the first rolling member 170 and the third rolling member 280. Moreover, in this embodiment, the first groove 132 and the first corresponding groove 139 are arranged such that the peaks 132m of the first groove 132 and the valleys 139v of the first corresponding groove 139 face each other. Also, the second groove 152 and the second corresponding groove 159 are arranged such that the peaks 152m of the second groove 152 and the valleys 159v of the second corresponding groove 159 face each other. In this way, as shown in Figure 9, the first rolling member 170 and the third rolling member 280 can be positioned such that their positions in the X direction are the same. As a result, as in this embodiment, for example, a pair of the first rolling member 170 and the third rolling member 280 can be placed within a single slit portion 195c, and the movement of the pair of the first rolling member 170 and the third rolling member 280 can be permitted and restricted by the slit portion 195c. In this way, the oscillation of the torque transmission mechanism 100c in the rotation axis AX direction can be suppressed with a simpler configuration.

[0055] D. Fourth Embodiment: Figure 10 is a schematic cross-sectional view showing the general configuration of the torque transmission mechanism 100d in the fourth embodiment. Similar to Figures 8 and 9, Figure 10 shows cross-sections of the torque transmission mechanism 100d along the X and Z directions. Unlike the first embodiment, this embodiment includes a first reduction unit 101, a second reduction unit 102, and a connecting member 103. The torque transmission mechanism 100d in this embodiment is the same as in the first embodiment unless otherwise specified.

[0056] The first reduction gear 101 is configured similarly to the torque transmission mechanism 100 in the first embodiment. The second reduction gear 102 is configured substantially the same as the first reduction gear 101, for example. The second reduction gear 102 includes a fourth member 330, a fifth member 350, one or more fourth rolling members 370, and a third regulating member 390. In other embodiments, for example, the parts of the second reduction gear 102 and the parts of the first reduction gear 101 can be swapped. The second reduction gear 102 is arranged alongside the first reduction gear 101 in the Z direction. As a result, the fourth member 330 and the fifth member 350 are arranged alongside the first member 130 and the second member 150 in the Z direction. Specifically, in this embodiment, the second reduction unit 102 is located on the +Z direction side of the first reduction unit 101, so the fourth member 330 and the fifth member 350 are arranged on the +Z direction side of the first member 130 and the second member 150.

[0057] The fourth member 330 corresponds to the first member 130 in the first reduction gear 101, and is configured substantially the same as the first member 130, for example. The fourth member 330 has a cylindrical shape. The fourth member 330 is configured to be rotatable around the rotation axis AX. The fourth member 330 has an outer circumferential surface 331 on which a fifth groove 332 is provided. The fifth groove 332 is configured substantially the same as the first groove 132, for example. The fifth groove 332 has a zigzag shape that extends around the rotation axis AX and makes a full rotation around the outer circumferential surface 131 in the circumferential direction DC. The fifth groove 332 has a periodic wave shape with peaks 332m and troughs 332v, and has a period T5. The period T5 may be the same as or different from periods T1 and T2. In this embodiment, the period T5 is 1. In this embodiment, the first groove 132 and the fifth groove 332 are arranged such that the peak portion 132m of the first groove 132 and the valley portion 332v of the fifth groove 332 face each other.

[0058] The fifth member 350 corresponds to the second member 150 in the first reduction gear 101, and is configured substantially the same as the second member 150, for example. The fifth member 350 has an annular shape that surrounds the fourth member 330. The fifth member 350 is configured to be rotatable around the rotation axis AX. The fifth member 350 has an inner circumferential surface 351 on which the sixth groove 352 is provided. The sixth groove 352 is configured substantially the same as the second groove 152, for example. The sixth groove 352 has a zigzag shape that extends around the rotation axis AX and makes a full circle around the inner circumferential surface 351 in the circumferential direction DC. The sixth groove 352 has a periodic wave shape with peaks 352m and troughs 352v. Furthermore, the number of peaks 332m and troughs 332v in the fifth groove 332 is different from the number of peaks 352m and troughs 352v in the sixth groove 352. In other words, the period T6 of the sixth groove 352 is different from the period T5 of the fifth groove 332. Period T6 may be the same as or different from periods T1 and T2. In this embodiment, the relationship between the magnitudes of periods T6 and T5 is the same as the relationship between the magnitudes of periods T2 and T1. Specifically, in this embodiment, period T6 is 12. In this embodiment, the second groove 152 and the sixth groove 352 are arranged such that the peak portion 152m of the second groove 152 and the valley portion 352v of the sixth groove 352 face each other.

[0059] The fourth rolling member 370 corresponds to the first rolling member 170 in the first reduction gear 101, and is configured in substantially the same manner as the first rolling member 170. The fourth rolling member 370 is positioned within the fifth groove 332 and the sixth groove 352, and is configured to be able to roll within the fifth groove 332 and the sixth groove 352.

[0060] The third restricting member 390 corresponds to the first restricting member 190 in the first reduction gear 101 and is configured substantially the same as the first restricting member 190. The third restricting member 390 is positioned between the fourth member 330 and the fifth member 350. The third restricting member 390 allows the fourth rolling member 370 to move along the rotation axis AX, while restricting the movement of the fourth rolling member 370 about the rotation axis AX. The third restricting member 390 achieves the allowance and restriction of the movement of the fourth rolling member 370 by a slit portion, similar to the first restricting member 190.

[0061] The connecting member 103 connects the first reduction unit 101 and the second reduction unit 102. More specifically, the connecting member 103 connects the second member 150 and the fourth member 330 so that they can rotate around the rotation axis AX. In this embodiment, the connecting member 103 is positioned between the second member 150 and the fourth member 330 in the Z direction and is fixed to the upper end of the second member 150 and the lower end of the fourth member 330.

[0062] In this embodiment, similar to the second embodiment, rotational speed can be achieved in stages between the first member 130 and the second member 150 in the first reduction unit 101, and between the fourth member 330 and the fifth member 350 in the second reduction unit 102. Specifically, for example, when the first member 130 is used as the input shaft, a reduction ratio RR1a is achieved between the first member 130 and the second member 150 in the first reduction unit 101. At this time, the rotation of the second member 150 is transmitted to the fourth member 330 via the connecting member 103. Furthermore, in the second reduction unit 102, reduction is achieved between the fourth member 330 and the fifth member 350 via the fourth rolling member 370. In this case, the reduction ratio RR4a achieved between the fourth member 330 and the fifth member 350 corresponds to the value obtained by dividing the period T5 by the period T6. As a result, a reduction ratio RR5a is achieved between the first member 130, which acts as the input shaft, and the fifth member 350, which acts as the output shaft. The reduction ratio RR5a corresponds to the product of the reduction ratio RR1a and the reduction ratio RR4a. Furthermore, when the fifth member 350 is used as the input shaft, a reduction ratio RR4b is achieved between the fifth member 350 and the fourth member 330 in the second reduction unit 102, and a reduction ratio RR1b is achieved in the first reduction unit 101. As a result, a reduction ratio RR5b is achieved between the fifth member 350, which acts as the input shaft, and the first member 130, which acts as the output shaft. The reduction ratio RR5b corresponds to the product of the reduction ratio RR1b and the reduction ratio RR4b. In other words, in this case, the rotation input to the torque transmission mechanism 100d is accelerated and output.

[0063] In this embodiment, at least one first rolling member 170 is configured to be located at the peak 132m of the first groove 132 when at least one fourth rolling member 370 is located at the valley 332v of the fifth groove 332. Furthermore, the first rolling member 170 is configured to be located at the peak 152m of the second groove 152 when at least one fourth rolling member 370 is located at the valley 352v of the sixth groove 352. Figure 10 shows that when one rolling member 170q included in the first rolling member 170 is located at the peaks 132m and 152m, one rolling member 370q included in the fourth rolling member 370 is located at the valleys 332v and 352v. Furthermore, when one rolling member 170p included in the first rolling member 170 is located in the valleys 132v and 152v, it is shown that one rolling member 370p included in the fourth rolling member 370 is located in the peaks 332m and 352m. Although not shown in the illustration, when rolling member 170p is located in the valleys 132v and 152v, rolling member 370p is located in the peaks 332m and 352m. Similarly, when rolling member 170q is located in the peaks 132m and 152m, rolling member 370q is located in the valleys 332v and 352v.

[0064] In the torque transmission mechanism 100d of the fourth embodiment described above, the first reduction unit 101 and the second reduction unit 102 are arranged side by side in the Z direction, and the second member 150 of the first reduction unit 101 and the fourth member 330 of the second reduction unit 102 are rotatably connected around the rotation axis AX by a connecting member 103. In the second reduction unit 102, the fourth rolling member 370, which is located in the fifth groove 332 of the fourth member 330 and the sixth groove 352 of the fifth member 350, is configured to be rotatable within the fifth groove 332 and the sixth groove 352. Within the fifth groove 332 and the sixth groove 352, movement of the fourth rolling member 370 along the rotation axis AX is permitted, while movement of the fourth rolling member 370 around the rotation axis AX is restricted. Furthermore, the number of peaks 332m and valleys 332v in the fifth groove 332 is different from the number of peaks 352m and valleys 352v in the sixth groove 352. Therefore, the rotational speed can be reduced in stages between the first member 130 and the second member 150, and between the fourth member 330 and the fifth member 350, allowing for a more space-saving configuration of the torque transmission mechanism 100d in the radial direction while achieving a higher reduction ratio. In other embodiments, further gradual reduction may be achieved by connecting other reduction units to, for example, the first reduction unit 101 or the second reduction unit 102. Also, for example, the configuration in the third embodiment and the configuration in the fourth embodiment may be combined to achieve further gradual reduction.

[0065] Furthermore, in this embodiment, when the rolling member 170q is located at the peaks 132m and 152m, the rolling member 370q is located at the valleys 332v and 352v. This allows the first rolling member 170 and the fourth rolling member 370 to move in opposite directions relative to each other in the direction of the rotation axis AX, thereby suppressing the oscillation of the torque transmission mechanism 100d in the direction of the rotation axis AX caused by the movement of the first rolling member 170 and the fourth rolling member 370.

[0066] E. Fifth Embodiment: Figure 11 is a perspective view showing the schematic configuration of the torque transmission mechanism 100e in the fifth embodiment. Figure 12 is an exploded perspective view showing the schematic configuration of the torque transmission mechanism 100e. Figure 13 is a cross-sectional view taken along line XIII-XIII of Figure 11. Figure 14 is a cross-sectional view taken along line XIV-XIV of Figure 11. In this embodiment, the configuration of the first regulating member 190e differs from that of the first embodiment. In this embodiment, the torque transmission mechanism 100e is the same as in the first embodiment unless otherwise described.

[0067] As shown in Figures 11, 12, and 14, the first regulating member 190e in this embodiment comprises a columnar member 211, a first annular member 215, and a second annular member 220.

[0068] The first annular member 215 has an annular shape. The first annular member 215 is positioned such that its axial direction is aligned with the Z direction. The first annular member 215 is provided with a plurality of first through holes 216. The first through holes 216 penetrate the first annular member 215 in the Z direction. In this embodiment, the first annular member 215 is provided with 10 first through holes 216.

[0069] The second annular member 220 has an annular shape. The second annular member 220 is positioned such that its axial direction is aligned with the Z direction. The second annular member 220 is provided with a plurality of second through holes 221. The second through holes 221 penetrate the second annular member 220 in the Z direction. In this embodiment, the second annular member 220 is provided with 10 second through holes 221 corresponding to 10 first through holes 216.

[0070] In this embodiment, ten columnar members 211 are provided corresponding to ten first through holes 216 and ten second through holes 221. Each columnar member 211 has a cylindrical shape overall. The columnar members 211 are arranged so that their axial direction is along the Z direction. Each columnar member 211 has a head 212 and a shaft portion 213. The head 212 has a diameter larger than the opening diameter of the first through hole 216 and the opening diameter of the second through hole 221. The head 212 constitutes the upper end of the columnar member 211. The shaft portion 213 has a diameter slightly smaller than the opening diameter of the first through hole 216 and the opening diameter of the second through hole 221. Each columnar member 211 is inserted into the first through hole 216 and the second through hole 221 from the +Z direction side. Specifically, the shaft portion 213 of each columnar member 211 is positioned within the first through-hole 216 and the second through-hole 221, respectively. The head portion 212 of each columnar member 211 is positioned on the +Z direction side of the first annular member 215. The lower end of each columnar member 211 is fixed to the second annular member 220 via a fixing member 225 and the first through-hole 216, respectively. The fixing member 225 is composed of, for example, a bolt and a washer. With this configuration, the columnar members 211 are connected to each other horizontally by the first annular member 215 and the second annular member 220.

[0071] As shown in Figures 12 and 14, the columnar members 211 are connected horizontally, forming openings between adjacent columnar members 211 in the circumferential direction DC. In this embodiment, the first rolling members 170 are arranged in five of these openings Op. The opening width of each opening Op in the circumferential direction DC is slightly larger than the diameter of the first rolling member 170. The opening length of each opening Op in the Z direction is greater than the opening width of each opening Op. The openings Op, similar to the slit portion 195 described in the first embodiment, allow movement of each first rolling member 170 in the Z direction and restrict movement of each first rolling member 170 around the rotation axis AX. Specifically, the movement of the first rolling member 170 around the rotation axis AX is restricted by the columnar members 211 that define the openings Op. Thus, the first restricting member 190e in this embodiment achieves both the permission and restriction of movement of each first rolling member 170 through the openings Op. Furthermore, the first restricting member 190e and the first restricting member 190 described in the first embodiment are similar in that they both allow and restrict the movement of the first rolling member 170 through a groove-shaped opening extending in the Z direction.

[0072] The torque transmission mechanism 100e in the fifth embodiment described above also allows for the reduction of rotational speed between the first member 130 and the second member 150 via the first rolling member 170, in accordance with the first groove 132 and the second groove 152, without using a torque transmission pin.

[0073] Furthermore, a configuration similar to that of the first restricting member 190e in the fifth embodiment may be applied, for example, to the second restricting member 270 described in the second embodiment or the third restricting member 390 described in the fourth embodiment.

[0074] F. Sixth Embodiment: The torque transmission mechanism 100f of the sixth embodiment will be described using Figures 15 to 21. In this embodiment, the arrangement of the columnar members 211 in the first regulating member 190f differs from that of the fifth embodiment. The arrangement of the columnar members 211 is determined by the arrangement of the first through holes 216 in the first annular member 215 and the arrangement of the second through holes 221 in the second annular member 220. The torque transmission mechanism 100f in this embodiment is the same as that of the fifth embodiment unless otherwise specified.

[0075] (F-1. First aspect) Figure 15 is a schematic cross-sectional view showing the general configuration of the torque transmission mechanism 100f in the first aspect of the sixth embodiment. Figure 16 is an enlarged view of the area around the columnar member 211 in Figure 15. In the first aspect of the sixth embodiment, for the sake of simplicity, the configuration in which the torque transmission mechanism 100f comprises two first rolling members 170 will be described. Each of the first rolling members 170 is positioned in an opening Op formed by the two columnar members 211, similar to the fifth embodiment. In other words, in the first aspect of the sixth embodiment, the first regulating member 190f has four columnar members 211. In the first aspect, of the two first rolling members 170, one first rolling member 170A is positioned in the +X direction of the rotation axis AX, and the other first rolling member 170B is positioned in the -X direction of the rotation axis AX. In other words, the line segment VL0a connecting the rotation axis AX and the center point VCa of the first rolling member 170A, and the line segment VL0b connecting the rotation axis Ax and the center point VCb of the first rolling member 170B, are both parallel to the X-axis. Furthermore, the first rolling member 170A is positioned in the opening Op formed by the columnar members 211A and 211B, and the first rolling member 170B is positioned in the opening Op formed by the columnar members 211C and 211D.

[0076] In this embodiment, the opening width of the opening Op in the circumferential direction DC is slightly smaller than the diameters of the first rolling members 170A and 170B.

[0077] The columnar members 211A and 211B are positioned to contact the first rolling member 170A at a contact point 211P on the surface of the first rolling member 170A, thereby biasing the first rolling member 170A toward the second member 150. At this time, the contact point 211P is located in the region -X side of the straight line VL1a that passes through the center point VCa of the first rolling member 170A along the Y axis. In other words, the columnar members 211A and 211B bias the first rolling member 170A toward the second member 150 by contacting the first rolling member 170A toward the first rolling member 130 on the side of the straight line VL1a that is perpendicular to the line segment VL0a connecting the rotation axis AX and the center point VCa of the first rolling member 170A. The first restricting member 190f restricts the movement of the first rolling member 170A around the rotation axis AX by sandwiching the first rolling member 170A between the columnar members 211A and 211B and the second groove 152 provided in the second member 150, thereby providing three-point support for the first rolling member 170A.

[0078] Two columnar members 211, namely columnar members 211C and 211D, which demarcate the opening Op in which the first rolling member 170B is positioned, are arranged to contact the first rolling member 170B at a contact point 211P on the surface of the first rolling member 170B, thereby biasing the first rolling member 170B toward the second member 150. At this time, the contact point 211P is located in the region +X side of the straight line VL1b that passes through the center point VCb of the first rolling member 170B along the Y axis. In other words, the columnar members 211C and 211D bias the first rolling member 170B toward the second member 150 by contacting the first rolling member 170B toward the first member 130 on the side of the straight line VL1b that is perpendicular to the line segment VL0b connecting the rotation axis AX and the center point VCb of the first rolling member 170B. The first restricting member 190f restricts the movement of the first rolling member 170B around the rotation axis AX by sandwiching the first rolling member 170B between the columnar members 211C and 211D and the second groove 152 provided in the second member 150, thereby providing three-point support for the first rolling member 170B.

[0079] According to the torque transmission mechanism 100f in the first aspect of the sixth embodiment described above, two columnar members 211 contact one first rolling member 170, biasing the first rolling member 170 toward the second member 150. This makes it possible to reduce the rattle of the first rolling member 170 within the opening Op during torque transmission.

[0080] Furthermore, the number of first rolling members 170 is not limited to two, but may be three or more.

[0081] (F-2. Second aspect) In the first embodiment, a configuration is shown in which a plurality of first rolling members 170 are biased toward the second member 150, but a configuration in which a plurality of first rolling members 170 are biased toward the first member 130 is also possible. Alternatively, a portion of the plurality of first rolling members 170 may be biased toward the first member 130, and another portion may be biased toward the second member 150.

[0082] Figure 17 is a schematic cross-sectional view showing the general configuration of the torque transmission mechanism 100f in the second aspect of the sixth embodiment. Figure 18 is an enlarged view of the area around the columnar member 211 in Figure 17. Similar to the first aspect, in the second aspect, a configuration in which the torque transmission mechanism 100f comprises two first rolling members 170, namely the first rolling member 170A and the first rolling member 170B, will be described. The first rolling member 170A is positioned in the opening Op formed by the columnar members 211A and 211B, and the first rolling member 170B is positioned in the opening Op formed by the columnar members 211C and 211D.

[0083] As shown in Figures 17 and 18, in the second embodiment, the first rolling member 170A, which is positioned in the +X direction of the rotation axis AX, is biased toward the first member 130, and the first rolling member 170B is biased toward the second member 150.

[0084] Two columnar members 211, namely columnar members 211A and 211B, which define the opening Op in which the first rolling member 170A is positioned, contact the first rolling member 170A at the contact point 211P on the surface of the first rolling member 170A, and bias the first rolling member 170A toward the first member 130.

[0085] Similar to the first embodiment, the columnar members 211C and 211D contact the first rolling member 170B at the contact point 211P on the surface of the first rolling member 170B, biasing the first rolling member 170B toward the second member 150.

[0086] According to the torque transmission mechanism 100f in the second aspect of the sixth embodiment described above, a portion of the first rolling member 170 is biased toward the first member 130, and another portion is biased toward the second member 150. This makes it possible to reduce rattle of the first rolling member 170 within the opening Op when torque is transmitted.

[0087] Furthermore, the number of first rolling members 170 is not limited to two, but may be three or more.

[0088] (F-3. Third aspect) In the first and second embodiments, the first rolling member 170 was biased toward either the first member 130 or the second member 150, but the first rolling member 170 may also be biased toward the circumferential direction DC by the columnar member 211.

[0089] Figure 19 is a schematic cross-sectional view showing the general configuration of the torque transmission mechanism 100f in the third aspect of the sixth embodiment. Figure 20 is an enlarged view of the area around the columnar member 211 in Figure 19. Similar to the first and second aspects, the third aspect will also describe a configuration in which the torque transmission mechanism 100f comprises two first rolling members 170A and 170B. The first rolling member 170A is positioned in the opening Op formed by the columnar members 211A and 211B, and the first rolling member 170B is positioned in the opening Op formed by the columnar members 211C and 211D.

[0090] As shown in Figures 19 and 20, in the third embodiment, the first rolling member 170A and the first rolling member 170B are biased by the columnar member 211.

[0091] The columnar member 211A contacts the first rolling member 170A at a contact point 211P on the surface of the first rolling member 170A, biasing the first rolling member 170A toward the first member 130, the second member 150, and the columnar member 211B. The columnar member 211A contacts the first rolling member 170A at its end on the +Y side of the straight line VL2 passing through the center point VCa of the first rolling member 170A along the Y axis, so that when the first rolling member 170A moves around the rotation axis AX, the columnar members 211A and 211B, the first groove 132 provided in the first member 130, and the second groove 152 provided in the second member 150 clamp and restrict the movement of the first rolling member 170A in a three-point support manner.

[0092] The columnar member 211A, located on the +Y side of the first rolling member 170A, contacts the +Y end of the first rolling member 170A and biases the first rolling member 170A in the -Y direction, which is along the circumferential direction DC. At this time, the first rolling member 170A contacts the -Y end of the first groove 132 of the first member 130 and the -Y end of the second groove 152 of the second member 150 on the -Y side. In other words, the columnar member 211A biases the first rolling member 170A toward both the first member 130 and the second member 150. The first restricting member 190f restricts the movement of the first rolling member 170A around the rotation axis AX by sandwiching the first rolling member 170A so that it is supported at three points by the columnar member 211A, the first groove 132, and the second groove 152. In addition, the first rolling member 170A may, on the -Y side, contact not only the -Y end of the first groove 132 and the -Y end of the second groove 152, but also one of these ends with the columnar member 211B.

[0093] The columnar member 211C contacts the first rolling member 170B at a contact point 211P on the surface of the first rolling member 170B, biasing the first rolling member 170B toward the first member 130, the second member 150, and the columnar member 211D. At this time, the columnar member 211C contacts the first rolling member 170B at its end on the +Y side of the straight line VL2 that passes through the center point VCb of the first rolling member 170B along the X axis. The columnar member 211C contacts the first rolling member 170B in a region +Y side of the straight line VL2 that passes through the center point VCb of the first rolling member 170B along the X axis. As the first rolling member 170B moves around the rotation axis AX, the columnar members 211C and 211D, the first groove 132 provided in the first member 130, and the second groove 152 provided in the second member 150 clamp and restrict the movement of the first rolling member 170B by supporting it at three points.

[0094] The columnar member 211C, located on the +Y side of the first rolling member 170B, contacts the +Y end of the first rolling member 170B, similar to the columnar member 211A, and biases the first rolling member 170B in the -Y direction. In other words, the two first rolling members 170A and 170B, which are positioned on opposite sides of the rotation axis AX, are biased in the same direction. As a result, it is possible to maintain a state in which both the first rolling members 170A and 170B are properly biased.

[0095] According to the torque transmission mechanism 100f in the third embodiment described above, the columnar member 211 biases the two first rolling members 170 in a direction along the circumferential direction DC, thereby pressing the first rolling members 170 against both the first member 130 and the second member 150. Specifically, the first rolling members 170 are pressed against both the end of the first groove of the first member and the end of the second groove of the second member by the two columnar members 211, thereby reducing rattle that occurs during torque transmission.

[0096] (F-4. Fourth aspect) The third embodiment described above may be combined with the first or second embodiment described above. Figure 21 is a schematic cross-sectional view showing the general configuration of the torque transmission mechanism 100f in the fourth aspect of the sixth embodiment. As shown in Figure 21, the torque transmission mechanism 100f of the fourth embodiment has four first rolling members 170A, 170B, 170C, and 170D.

[0097] Of the four first rolling members 170, the first rolling members 170A and 170B are biased by the columnar members 211A and 211C, respectively, in the direction of -Y, which is along the circumferential direction DC, i.e., toward the first member 130 and the second member 150, respectively. The first rolling member 170C is biased toward the second member 150 by the columnar members 211E and 211F, respectively, in the same manner as in the first or second manner. The first rolling member 170D is biased toward the second member 150 by the columnar members 211G and 211H, respectively, in the same manner as in the first or second manner.

[0098] The torque transmission mechanism 100f in the fourth embodiment described above can achieve the same effects as in the first to third embodiments.

[0099] Furthermore, the number of the first rolling members 170 is not limited to four; it may be three or five or more.

[0100] In addition, in the first to fourth embodiments described above, the cross-sectional shape of the columnar member 211 in the XY plane may be an ellipse, semicircle, triangle, quadrilateral, or crescent shape, in addition to a circle.

[0101] G. Seventh Embodiment: In this embodiment, the configuration of the first regulating member 190g differs from that of the fifth embodiment. In this embodiment, the torque transmission mechanism 100g is the same as in the fifth embodiment, except for aspects not specifically described.

[0102] Figure 22 is an enlarged view of the area around the columnar member 211 in Figure 14. In this embodiment, the first annular member 215 has a bearing portion 217 at a position corresponding to the first through hole 216 in which the columnar member 211 is located. The bearing portion 217 is a radial type ball bearing. The bearing portion 217 holds the columnar member 211 relative to the first annular member 215 so that it can rotate around a central axis BX along the Z-axis direction of the columnar member 211. The columnar member 211 has a cylindrical shape with a circular cross-section parallel to the XY plane.

[0103] In this embodiment, the second through hole 221 has a bearing portion 217. The bearing portion 217 is a radial type ball bearing. The bearing portion 217 holds the columnar member 211 with respect to the second annular member 220 so that it can rotate around the central axis BX of the columnar member 211.

[0104] The bearings constituting the bearing section 217 may be radial ball bearings or thrust ball bearings. Alternatively, radial rolling bearings or thrust roller bearings may be used. Furthermore, metal plain bearings, plastic plain bearings, bearing units, etc., may also be used.

[0105] The columnar members 211 are arranged so that their axial direction is aligned with the Z direction. The columnar members 211 have a head portion 212 and a shaft portion 213. The head portion 212 has a diameter larger than the inner diameter of the bearing portion 217. The head portion 212 constitutes the upper end of the columnar member 211. The shaft portion 213 has a diameter approximately the same as the inner diameter of the bearing portion 217. Each columnar member 211 is inserted from the +Z direction side into the bearing portion 217 having a first through hole 216 and the bearing portion 217 having a second through hole 221, and is held by the bearing portion 217 having a first through hole 216 and the second through hole 221. In addition, a fixing member 225 having a diameter larger than the inner diameter of the bearing portion 217 is attached to the lower end of each columnar member 211, and functions as a retainer against the bearing portion 217 in the Z direction. The fixing member 225 is made up of, for example, a bolt and a washer. With this configuration, the columnar members 211 are connected to each other horizontally by the first annular member 215 and the second annular member 220, so as to be rotatable around the central axis BX.

[0106] According to the torque transmission mechanism 100g in the seventh embodiment described above, the first regulating member 190g has a first annular member 215, a second annular member 220, and a columnar member 211. The first annular member 215 and the second annular member 220 have a bearing portion 217, which holds the columnar member 211 so that it can rotate around the central axis BX. Because the columnar member 211 is rotatably held by the first annular member 215 and the second annular member 220, the columnar member 211 rotates in accordance with the rolling of the first rolling member 170 as shown in Figure 23, making it possible to reduce the friction between the first rolling member 170 and the columnar member 211. Figure 23 is an example diagram showing a configuration in which the torque transmission mechanism 100g has two first rolling members 170. It is desirable that the columnar member 211 has a cylindrical shape with a circular cross-sectional shape in the XY plane. The cylindrical shape of the columnar member 211 allows it to rotate more smoothly in accordance with the rolling motion of the first rolling member.

[0107] Furthermore, the configuration shown in the seventh embodiment may be combined with the configurations shown in each aspect of the sixth embodiment. With such a configuration, it is possible to suppress the increase in friction that occurs when biasing the first rolling member 170.

[0108] H. Other embodiments: (H-1) In each of the above embodiments, the first rolling member 170 has a spherical shape. In contrast, the first rolling member 170 does not have to be spherical as long as it can roll within the first groove 132 and the second groove 152. For example, the first rolling member 170 may have a curved shape other than a spherical shape that can roll within the first groove 132 and the second groove 152.

[0109] (H-2) In each of the above embodiments, a plurality of first rolling members 170 are provided. However, the number of first rolling members 170 may be one. Furthermore, the number of first rolling members 170 and the manner in which they are arranged may be arbitrary, as long as torque transmission by the torque transmission mechanism 100 is possible and each first rolling member 170 can be arranged in the first groove 132 and the second groove 152. For example, the number of first rolling members 170 may be two or more and four or six or more. Similarly, the number and arrangement of the second rolling members 250, third rolling members 280, and fourth rolling members 370 may be arbitrary. Furthermore, the number of first rolling members 170, second rolling members 250, third rolling members 280, and fourth rolling members 370 may be the same or different.

[0110] (H-3) In each of the above embodiments, the first bearing portion 201 is provided, but it may not be provided. Similarly, the second bearing portion 202 may not be provided.

[0111] (H-4) In each of the above embodiments, the period T1 of the first groove 132 is smaller than the period T2 of the second groove 152, but the period T1 may be larger than the period T2. In this case, when the first member 130 is used as the input shaft, acceleration is achieved between the first member 130 and the second member 150. Also, when the second member 150 is used as the input shaft, deceleration is achieved between the second member 150 and the first member 130. Similarly, the period T3 may be larger than the period T4. Similarly, the period T5 may be larger than the period T6.

[0112] (H-5) In the above embodiment, the first groove 132 and the second groove 152 have a triangular wave shape, but they do not have to have a triangular wave shape. For example, the first groove 132 and the second groove 152 may have a zigzag shape such as a sinusoidal curve shape or a sawtooth wave shape. Similarly, the third groove 162, the fourth groove 232, the fifth groove 332, and the sixth groove 352 do not have to have a triangular wave shape.

[0113] (H-6) In each of the above embodiments, the number of peaks 132m and valleys 132v of the first groove 132 and the number of peaks 152m and valleys 152v of the second groove 152 are different, but they may be the same. In this case, the period T1 of the first groove 132 and the period T2 of the second groove 152 are the same. That is, the torque transmission mechanism 100 does not have to be configured as a reduction gear.

[0114] For example, Figure 24 is an explanatory diagram of a torque transmission mechanism 100h, which is a first example of a torque transmission mechanism in another embodiment. Figure 25 is an explanatory diagram of a torque transmission mechanism 100h, which is a second example of a torque transmission mechanism in another embodiment. Figures 24 and 25 show the outer circumferential surface 131t and the inner circumferential surface 151t, substantially the same as in Figure 5. In the examples of Figures 24 and 25, the number of peaks 132m and valleys 132v of the first groove 132 and the number of peaks 152m and valleys 152v of the second groove 152f are the same, and are 1 each. Also, in the examples of Figures 24 and 25, the first rolling member 170 is provided as a rolling member 170A and a rolling member 170B, and the first restricting part 199 is provided as a restricting part 199A and a restricting part 199B. In the example shown in Figure 24, when viewing the outer surface 131t and inner surface 151t along the radial direction DR, the first member 130 and the second member 150f are positioned such that the peaks 132m of the first groove 132 and the valleys 152v of the second groove 152f are at the same position in the circumferential direction DC, that is, the phases of the first groove 132 and the second groove 152f are opposite. In this way, when rotation is input to one of the first member 130 or the second member 150f, the other can output a rotation in the opposite direction to the input rotation. Furthermore, as shown in Figure 25, when viewing the outer surface 131t and inner surface 151t along the radial direction DR, it is also possible to position the first member 130 and the second member 150f such that the peaks 132m of the first groove 132 and the peaks 152m of the second groove 152f are located at the same position in the circumferential direction DC, that is, the phases of the first groove 132 and the second groove 152f are the same. Note that in Figure 25, the first groove 132 and the second groove 152f are shown offset to facilitate understanding of the technology, but in reality, the first groove 132 and the second groove 152f overlap. In this way, when rotation is input to one of the first member 130 or the second member 150f, the other can output rotation in the same direction as the input rotation. Thus, even if the periods T1 and T2 are the same, torque transmission can be achieved between the first member 130 and the second member 150f without using a torque transmission pin.Furthermore, using the same first member 130, second member 150f, and first regulating member 190, a forward-rotating type torque transmission mechanism that outputs rotation in the same direction as the input rotation, and a reverse-rotating type torque transmission mechanism that outputs rotation in the opposite direction to the input rotation can be easily constructed.

[0115] (H-7) In the third embodiment described above, the peaks 132m of the first groove 132 and the valleys 139v of the first corresponding groove 139 face each other, and the peaks 152m of the second groove 152 and the valleys 159v of the second corresponding groove 159 face each other. In contrast, the peaks 132m and the valleys 139v do not have to face each other. Also, the peaks 152m and the valleys 159v do not have to face each other. In this case, for example, the peaks 132m and the valleys 139v may face each other, while the peaks 152m and the valleys 159v do not face each other. Also, for example, the peaks 152m and the valleys 159v may face each other, while the peaks 132m and the valleys 139v do not face each other. Similarly, in the fourth embodiment described above, the peak portion 132m of the first groove 132 and the valley portion 332v of the fifth groove 332 do not have to face each other. Also, the peak portion 152m of the second groove 152 and the valley portion 352v of the sixth groove 352 do not have to face each other.

[0116] Figure 26 is an explanatory diagram of a torque transmission mechanism 100i (see Figure 26), which is a third example of a torque transmission mechanism in another embodiment. Figure 26 shows the outer circumferential surface 131t and the inner circumferential surface 151t, substantially the same as in Figure 5. The torque transmission mechanism 100i is provided with a first groove 132 and a first corresponding groove 139, and a second groove 152h and a second corresponding groove 159h, similar to the third embodiment. In the example in Figure 26, the number of peaks 152m and valleys 152v in the second groove 152h, and the number of peaks 159m and valleys 159v in the second corresponding groove 159h are each 2. In addition, in the example in Figure 26, the first rolling member 170 is provided as a rolling member 170A and a rolling member 170B, and the first restricting part 199 is provided as a restricting part 199A and a restricting part 199B. Furthermore, the third rolling member 280 is provided as a rolling member 280A and a rolling member 280B, and the second restricting section 205 is provided as a restricting section 205A and a restricting section 205B. The restricting sections 205A and 205B each have a slit portion extending in the Z direction, substantially the same as the restricting sections 199A and 199B. The restricting sections 205A and 205B each allow movement of the rolling members 280A and 280B along the rotation axis AX, and restrict movement of the rolling members 280A and 280B about the rotation axis AX, respectively, through their respective slit portions. In the example of Figure 26, unlike the third embodiment, the peak portion 132m and the valley portion 139v do not face each other, and the peak portion 152m and the valley portion 159v do not face each other. However, in the example shown in Figure 26, similar to the third embodiment, at least one first rolling member 170 is located at the peak 132m of the first groove 132 when at least one third rolling member 280 is located at the valley 139v of the first corresponding groove 139. Also, at least one first rolling member 170 is located at the peak 152m of the second groove 152 when at least one third rolling member 280 is located at the valley 159v of the second corresponding groove 159h. Figure 26 shows that the rolling member 170A is located at the peaks 132m and 152m, and the rolling member 280A is located at the valleys 139v and 159v. In this way, similar to the third embodiment, it is possible to suppress the oscillation of the torque transmission mechanism 100i in the Z direction due to the movement of the first rolling member 170 and the third rolling member 280.Thus, even in configurations where the peak portion 132m and the valley portion 139v do not face each other, and the peak portion 152m and the valley portion 159v do not face each other, oscillation in the torque transmission mechanism 100iZ direction can be suppressed.

[0117] I. Other forms: This disclosure is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit. For example, this disclosure can also be implemented in the following forms. The technical features in the embodiments described above that correspond to the technical features in each of the forms described below can be replaced or combined as appropriate in order to solve some or all of the problems of this disclosure, or to achieve some or all of the effects of this disclosure. Furthermore, if such technical features are not described as essential in this specification, they can be deleted as appropriate.

[0118] (1) According to a first embodiment of the present disclosure, a torque transmission mechanism is provided. This torque transmission mechanism comprises: a first member having a cylindrical shape and configured to be rotatable around a rotation axis, having an outer circumferential surface provided with a zigzag-shaped first groove extending around the rotation axis; a second member having an annular shape surrounding the first member and configured to be rotatable around the rotation axis, having an inner circumferential surface provided with a zigzag-shaped second groove extending around the rotation axis; one or more spherical first rolling members disposed within the first groove and the second groove and configured to roll within the first groove and the second groove; and a first restricting member disposed between the first member and the second member, allowing the first rolling members to move along the rotation axis and restricting the first rolling members to move around the rotation axis, wherein the first restricting member comprises a columnar member having a central axis along the rotation axis, restricting the movement of the first rolling members, and the columnar member is cylindrical and configured to be rotatable around the central axis. In this configuration, torque can be transmitted between the first member and the second member via the first rolling member, according to the first groove and the second groove, without using a torque transmission pin. Furthermore, since the columnar member that restricts the first rolling member is rotatably attached to the first restricting member, friction is less likely to occur between the first rolling member and the columnar member, thereby reducing torque transmission loss and improving durability.

[0119] (2) The torque transmission mechanism characterized in that the first groove and the second groove have a periodic wave shape having one or more peaks and valleys, and the number of peaks and valleys in the first groove is different from the number of peaks and valleys in the second groove. In this configuration, the first groove and the second groove have a periodic wave shape with one or more peaks and troughs, and since the number of peaks and troughs in the first groove is different from the number of peaks and troughs in the second groove, torque transmission that allows for speed increase and speed decrease is achieved.

[0120] (3) The above embodiment is characterized in that the first rolling member includes one rolling member and another rolling member. The torque transmission mechanism includes one rolling member and another rolling member, and the first restricting member has one restricting part that allows movement of one rolling member along its axis of rotation and restricts movement of the first rolling member about its axis of rotation, and another restricting part that allows movement of the other rolling member along its axis of rotation and restricts movement of the other rolling member about its axis of rotation. As a result, torque is transmitted by multiple rolling members, the load on one rolling member is reduced, and deterioration or damage to the rolling member can be prevented.

[0121] (4) The torque transmission mechanism in the above embodiment is characterized in that the first regulating member has a bearing portion, and the columnar member is rotatably supported by the bearing portion. The first regulating member has a bearing portion that holds the columnar member so as to be rotatable around a central axis along the Z direction. Because the first regulating member has a bearing portion that holds the columnar member so as to be rotatable around a central axis along the Z direction, the columnar member can rotate in accordance with the rolling motion generated when the first rolling member moves around the rotation axis. By rotating the columnar member in accordance with the rolling motion of the first rolling member, it is possible to reduce the friction generated between the first rolling member and the columnar member.

[0122] (5) A torque transmission mechanism characterized in that the columnar member contacts the first rolling member, and the columnar member biases the first rolling member toward at least one of the first member and the second member. With this configuration, since the first regulating member contacts the first rolling member and the columnar member biases toward at least one of the first member and the second member, it is possible to reduce rattle that occurs during torque transmission. [Explanation of symbols]

[0123] 100, 100b, 100c, 100d, 100e, 100f, 100g, 100h, 100i… Torque transmission mechanism, 101… First reduction unit, 102… Second reduction unit, 103… Connecting member, 130, 130c… First member, 131, 131c, 131t… Outer surface, 132… First groove, 132m… Peak, 132v… Valley, 139… First corresponding groove, 139m… Peak, 139v… Valley, 150, 150b, 150c, 150f… Second member, 151, 151c, 151t… Inner surface, 152, 152f, 152h... Second groove, 152m... Peak section, 152v... Valley section, 159, 159h... Second corresponding groove, 159m... Peak section, 159v... Valley section, 161... Outer surface, 162... Third groove, 170... First rolling member, 170A, 170B, 170C, 170D, 170E, 170p, 170q... Rolling members, 190, 190e, 190f, 190g... First regulating member, 191... Main body section, 192... First flange section, 193... Second flange section, 194... Bolt, 195, 195c... Slit section, 196... Wall section, 199...First restricting section, 199A, 199B, 199C, 199D, 199E...Restricting section, 201...First bearing section, 202...Second bearing section, 205...Second restricting section, 205A, 205B...Restricting section, 211, 211A, 211B, 211C, 211D, 211E, 211F, 211G, 211H...Columnar member, 211P...Contact point, 212...Head section, 213...Shaft section, 215...First annular member, 216...First through hole, 217...Bearing section, 220...Second annular member, 221...Second through hole, 2 25...fixing member, 230...third member, 231...inner circumferential surface, 232...fourth groove, 250...second rolling member, 270...second regulating member, 280...third rolling member, 280A, 280B, 280p, 280q...rolling members, 330...fourth member, 331...outer circumferential surface, 332...fifth groove, 332m...peak section, 332v...valley section, 350...fifth member, 351...inner circumferential surface, 352...sixth groove, 352m...peak section, 352v...valley section, 370...fourth rolling member, 370p, 370q...rolling members, 390...third regulating member.

Claims

1. A first member having a cylindrical shape and configured to be rotatable about a rotation axis, the first member having an outer surface provided with a zigzag-shaped first groove extending about the rotation axis, A second member having an annular shape surrounding the first member and configured to be rotatable around the rotation axis, the second member having an inner circumferential surface provided with a zigzag-shaped second groove extending around the rotation axis, One or more spherical first rolling members are arranged in the first groove and the second groove and configured to be rotatable within the first groove and the second groove, The first regulating member is positioned between the first member and the second member, allowing the first rolling member to move along the rotation axis and restricting the first rolling member's movement around the rotation axis. The first regulating member comprises a columnar member having a central axis along the rotation axis, and the columnar member restricts the movement of the first rolling member. The torque transmission mechanism is characterized in that the columnar member has a cylindrical shape and is configured to be rotatable around the central axis.

2. A torque transmission mechanism according to claim 1, The first groove and the second groove have a periodic wave shape having one or more peaks and troughs. The number of peaks and valleys of the first groove, and the number of peaks and valleys of the second groove The torque transmission mechanism is characterized by having a different number of components.

3. A torque transmission mechanism according to claim 1, A torque transmission mechanism characterized in that the first rolling member includes one rolling member and another rolling member.

4. A torque transmission mechanism according to claim 1, The torque transmission mechanism is characterized in that the first regulating member has a bearing portion, and the columnar member is rotatably supported by the bearing portion.

5. A torque transmission mechanism according to claim 1, The columnar member contacts the first rolling member, The torque transmission mechanism is characterized in that the columnar member biases the first rolling member toward at least one of the first member and the second member.

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