Torque transmission mechanism

Abstract

A torque transmission mechanism does not require an inner pin. A torque transmission mechanism is provided with: a first member having a cylindrical shape, the first member being configured so as to be rotatable about a rotation axis and having an outer peripheral surface in which a first groove is provided, the first groove having a zigzag shape extending about the rotation axis; a second member having an annular shape surrounding the first member, the second member being configured so as to be rotatable about the rotation axis and having an inner circumferential surface provided with a second groove having a zigzag shape extending about the rotation axis; one or more first rolling members disposed in the first groove and the second groove and configured so as to be capable of rolling in the first groove and the second groove; and a first restricting member disposed between the first member and the second member, allowing movement of the first rolling member along the rotation axis, and restricting movement of the first rolling member around the rotation axis.

Description

Technical Field

[0001] This disclosure relates to torque transmission mechanisms. Background Technology

[0002] Regarding torque transmission mechanisms, Patent Document 1 discloses an eccentric oscillating type reduction mechanism. In the reduction mechanism of Patent Document 1, the rotational component of the external gear is transmitted to the planetary carrier via the inner pin, thereby realizing torque transmission.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2019-132364

[0004] In the technology of Patent Document 1, when the mechanism is in operation, there is a possibility that the inner pin may break due to the shear load generated in the inner pin that bears the torque transmission. Summary of the Invention

[0005] According to one aspect of this disclosure, a torque transmission mechanism is provided. The torque transmission mechanism comprises: a first component having a cylindrical shape, the first component being rotatable about a rotation axis and having an outer peripheral surface provided with a first groove, the first groove being a serrated shape extending about the rotation axis; a second component having an annular shape surrounding the first component, the second component being rotatable about the rotation axis and having an inner peripheral surface provided with a second groove, the second groove being a serrated shape extending about the rotation axis; one or more first rolling components disposed within the first groove and the second groove and configured to roll within the first groove and the second groove; and a first limiting component disposed between the first component and the second component, allowing movement of the first rolling components along the rotation axis and limiting movement of the first rolling components about the rotation axis. Attached Figure Description

[0006] Figure 1 This is a perspective view showing a simplified structure of the torque transmission mechanism in the first embodiment.

[0007] Figure 2 This is an exploded perspective view showing a simplified structure of the torque transmission mechanism in the first embodiment.

[0008] Figure 3 yes Figure 1 Sectional view III-III.

[0009] Figure 4 yes Figure 1 Sectional view IV-IV.

[0010] Figure 5 This is the first explanatory diagram of the torque transmission mechanism in the first embodiment.

[0011] Figure 6 This is a second explanatory diagram of the torque transmission mechanism in the first embodiment.

[0012] Figure 7 This is a schematic cross-sectional view showing a simplified structure of the torque transmission mechanism in the second embodiment.

[0013] Figure 8 yes Figure 7 Sectional view of VIII-VIII.

[0014] Figure 9 This is a schematic cross-sectional view showing a simplified structure of the torque transmission mechanism in the third embodiment.

[0015] Figure 10 This is a schematic cross-sectional view showing a simplified structure of the torque transmission mechanism in the fourth embodiment.

[0016] Figure 11 This is a perspective view showing a simplified structure of the torque transmission mechanism in the fifth embodiment.

[0017] Figure 12 This is an exploded perspective view showing a simplified structure of the torque transmission mechanism in the fifth embodiment.

[0018] Figure 13 yes Figure 11 Sectional view XIII-XIII.

[0019] Figure 14 yes Figure 11 Sectional view of XIV-XIV.

[0020] Figure 15 This is an explanatory diagram of the first example of a torque transmission mechanism in other embodiments.

[0021] Figure 16 This is an explanatory diagram of a second example of a torque transmission mechanism in other embodiments.

[0022] Figure 17 This is an explanatory diagram of a third example of a torque transmission mechanism in other embodiments.

[0023] Explanation of reference numerals in the attached figures

[0024] 100, 100b, 100c, 100d, 100e, 100f, 100g, 100h… Torque transmission mechanism, 101… First reduction section, 102… Second reduction section, 103… Connecting component, 130, 130c… First component, 131, 131c, 131t… Outer peripheral surface, 132… First groove, 132m… Peak, 132v… Valley, 139… First corresponding groove, 139m… Peak, 139v… Valley, 150, 150b, 150c, 150f… Second component, 151, 151c… 151t…Inner peripheral surface, 152, 152f, 152h…Second groove, 152m…Peak, 152v…Valley, 159, 159h…Second corresponding groove, 159m…Peak, 159v…Valley, 161…Outer peripheral surface, 162…Third groove, 170…First rolling component, 170A, 170B, 170C, 170D, 170E, 170p, 170q…Rolling component, 190, 190e…First limiting component, 191…Main body, 192…First flange-like part, 193…Second flange-like part, 194… Bolt, 195, 195c…slit portion, 196…wall portion, 199…first limiting portion, 199A, 199B, 199C, 199D, 199E…limiting portion, 201…first bearing portion, 202…second bearing portion, 205…second limiting portion, 205A, 205B…limiting portion, 211…columnar member, 212…head, 213…shaft portion, 215…first annular member, 216…first through hole, 220…second annular member, 221…second through hole, 225…fixing member, 230…third member, 23 1…Inner peripheral surface, 232…Fourth groove, 250…Second rolling member, 270…Second limiting member, 280…Third rolling member, 280A, 280B, 280p, 280q…Rolling member, 330…Fourth member, 331…Outer peripheral surface, 332…Fifth groove, 332m…Peak, 332v…Valley, 350…Fifth member, 351…Inner peripheral surface, 352…Sixth groove, 352m…Peak, 352v…Valley, 370…Fourth rolling member, 370p, 370q…Rolling member, 390…Third limiting member. Detailed Implementation

[0025] A. First implementation method:

[0026] Figure 1 This is a perspective view showing a simplified structure of the torque transmission mechanism 100 in the first embodiment. Figure 2 This is an exploded perspective view showing the simplified structure of the torque transmission mechanism 100. Figure 1The diagram shows arrows indicating the X, Y, and Z directions, which are orthogonal to each other. The X and Y directions are parallel to the horizontal plane, and the Z direction is vertically upward. In other diagrams, the arrows indicating the X, Y, and Z directions are also appropriately aligned with the directions shown in the diagram. Figure 1 The corresponding methods are illustrated. In the following explanation, when the direction is determined, the direction pointed to by the arrow is marked as "+" and its opposite direction is marked as "-" in each diagram, and positive and negative symbols are used in the direction markings. Hereinafter, the +Z direction will also be referred to as "up" and the -Z direction as "down".

[0027] In this embodiment, the torque transmission mechanism 100 is configured as a speed reduction device. For example... Figure 1 and Figure 2 As shown, the torque transmission mechanism 100 includes a first component 130, a second component 150, one or more first rolling components 170, and a first limiting component 190. Furthermore, the torque transmission mechanism 100 in this embodiment includes a first bearing portion 201 and a second bearing portion 202.

[0028] The torque transmission mechanism 100 in this embodiment has a cylindrical shape as a whole. The torque transmission mechanism 100 is configured such that its rotation axis AX is along the Z direction. In this embodiment, the rotation axis AX corresponds to the rotation axis of the first component 130 and the rotation axis of the second component 150. It should be noted that in this disclosure, "cylindrical shape" includes both solid and hollow cylindrical shapes. Furthermore, the direction along the rotation axis AX will be referred to as the rotation axis AX direction below.

[0029] The circumferential direction DC of the torque transmission mechanism 100 corresponds to the circumferential direction of the first component 130 and the circumferential direction of the second component 150. In this disclosure, the circumferential direction DC is defined as the counterclockwise direction when the torque transmission mechanism 100 is viewed from the +Z direction side. Furthermore, unless otherwise specified, "counterclockwise" hereafter means counterclockwise when the torque transmission mechanism 100 is viewed from the +Z direction side. The same applies to "clockwise".

[0030] The first component 130 has a cylindrical shape. More specifically, the first component 130 has a hollow cylindrical shape. The first component 130 is arranged such that its axial direction is along the Z direction. In this embodiment, the first component 130 is arranged horizontally at the innermost part of each portion of the torque transmission mechanism 100. The first component 130 is configured to be rotatable about the rotation axis AX of the torque transmission mechanism 100. Figure 2As shown, the first component 130 has an outer peripheral surface 131. A first groove 132 is provided on the outer peripheral surface 131. The first groove 132 has a serrated shape extending around the rotation axis AX on the outer peripheral surface 131. In this specification, "serrated shape" means a shape that reciprocates more than once in a certain direction and extends in a direction orthogonal to that direction. That is, the serrated shape has more than one turning point. The turning point of the serrated shape can be pointed or curved. Details regarding the first groove 132 will be described later.

[0031] like Figure 1 and Figure 2 As shown, the second component 150 has an annular shape surrounding the first component 130. That is, the inner diameter of the second component 150 is larger than the outer diameter of the first component 130. The second component 150 is arranged such that its axial direction is along the Z direction. In this embodiment, among the various parts of the torque transmission mechanism 100, the second component 150 is arranged on the outermost side in the horizontal direction. The second component 150 is configured to be rotatable about the rotation axis AX. Figure 2 As shown, the second component 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 serrated shape extending around the rotation axis AX on the inner circumferential surface 151. Details about the second groove 152 will be described later.

[0032] Figure 3 yes Figure 1 Sectional view III-III. Figure 4 yes Figure 1 Sectional view IV-IV. (See example) Figure 3 and Figure 4 As shown, the first rolling member 170 is disposed 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 is disposed at the intersection of the first groove 132 and the second groove 152 when viewed along the radial direction of the torque transmission mechanism 100, and rolls within the first groove 132 and the second groove 152. By rolling within the first groove 132, the first rolling member 170 moves relative to the first member 130. Furthermore, by rolling within the second groove 152, the first rolling member 170 moves relative to the second member 150. In this embodiment, the first rolling member 170 is spherical. The first rolling member 170 is configured, for example, as a so-called steel ball, made of stainless steel, steel, etc. As described below, the first rolling member 170 transmits torque between the first member 130 and the second member 150.

[0033] In this embodiment, the first rolling member 170 includes rolling members 170A, 170B, 170C, 170D, and 170E. Without distinguishing between the rolling members 170A to 170E, they are simply referred to as the first rolling member 170. When the torque transmission mechanism 100 is viewed from the +Z direction side, the rolling members 170A, 170B, 170C, 170D, and 170E are arranged sequentially in the circumferential DC direction.

[0034] like Figure 3 and Figure 4 As shown, a first limiting member 190 is disposed between a first member 130 and a second member 150. In this embodiment, the first limiting member 190 is integrally hollow and cylindrical. The first limiting member 190 is configured such that its axial direction is along the Z-direction.

[0035] The first limiting member 190 has a main body portion 191, a first flange-shaped portion 192, and a second flange-shaped portion 193. The main body portion 191 is the portion of the first limiting member 190 disposed within the annulus of the second member 150. The first flange-shaped portion 192 is an annular flange-shaped portion constituting the lower end of the first limiting member 190. The second flange-shaped portion 193 is an annular flange-shaped portion constituting the upper end of the first limiting member 190. Figure 1 and Figure 4 As shown, the first flange-like portion 192 is not disposed within the annulus of the second component 150, but rather below the lower end of the first component 130 and the lower end of the second component 150. Similarly, the second flange-like portion 193 is disposed above the upper end of the first component 130 and the upper end of the second component 150. In this embodiment, the first flange-like portion 192 is integrally formed with the main body portion 191. The second flange-like portion 193 is configured as a separate cover from the main body portion 191 and is fixed to the main body portion 191 by bolts 194. The outer diameter of the main body portion 191 is smaller than the inner diameter of the second component 150. On the other hand, the outer diameters of the first flange-like portion 192 and the second flange-like portion 193 are larger than the inner diameter of the second portion. The inner diameter of the main body portion 191 is larger than the outer diameter of the first component 130. On the other hand, the inner diameters of the first flange-like portion 192 and the second flange-like portion 193 are smaller than the outer diameter of the first component 130. The inner diameter of the first flange-shaped portion 192 is approximately the same as the inner diameter of the second flange-shaped portion 193. The outer diameter of the first flange-shaped portion 192 is approximately the same as the outer diameter of the second flange-shaped portion 193.

[0036] like Figures 2 to 4As shown, the main body 191 has slit portions 195. In this embodiment, the main body 191 has five slit portions 195. These are configured as openings extending along the rotation axis AX, i.e., along the Z direction. A wall portion 196 of the main body 191 is disposed between the openings of each slit portion 195. The wall portion 196 corresponds to a wall in the circumferential DC direction among the walls that divide the openings of the slit portions 195. Figure 2 and Figure 4 As shown, in this embodiment, the lower end of the opening of the slit portion 195 is divided by the first flange-like portion 192. Furthermore, as... Figure 4 As shown, the upper end of the opening of the slit portion 195 is divided by the second flange-like portion 193. The opening width in the circumferential direction DC of the opening of the slit portion 195 is slightly larger than the diameter of the first rolling member 170. Furthermore, the opening length in the Z direction of the slit portion 195 is greater than the opening width of the slit portion 195.

[0037] The first limiting member 190 has a first limiting portion 199. The first limiting portion 199 allows the first rolling member 170 to move along the rotation axis AX, i.e., to move in the Z direction. On the other hand, the first limiting portion 199 restricts the movement of the first rolling member 170 about the rotation axis AX. In this embodiment, the first limiting portion 199 includes limiting portions 199A, 199B, 199C, 199D, and 199E. Hereinafter, without distinguishing between limiting portions 199A to 199E, they will also be referred to simply as the first limiting portion 199. Furthermore, the first limiting portion 199 will also be referred to simply as the limiting portion.

[0038] Specifically, in this embodiment, the first limiting portion 199 has the aforementioned slit portion 195, which both allows and restricts the movement of the first rolling member 170. For example, the rolling member 170A is disposed within the slit portion 195 of the limiting portion 199A. As a result, movement of the rolling member 170A along the Z direction of the slit portion 195 is allowed. On the other hand, the movement of the rolling member 170A about the rotation axis AX is restricted by the wall portion 196, which divides the slit portion 195. Similarly, rolling members 170B to 170E are respectively disposed within the slit portions 195 of the limiting portions 199B to 199E. It should be noted that the number of the first rolling members 170 is preferably determined, for example, taking into account the strength of the first limiting member 190. Specifically, the more first rolling members 170 there are, the larger the total opening area of ​​each slit 195 in the first restricting member 190, and sometimes the strength of the first restricting member 190 will decrease. The number of first rolling members 170 is preferably determined to be small enough to suppress such a decrease in strength.

[0039] A first bearing portion 201 is disposed between the first component 130 and the first limiting component 190. The first bearing portion 201 holds the first component 130 so that it can rotate relative to the first limiting component 190 about the rotation axis AX. The first bearing portion 201 is constructed of various bearings such as ball bearings and needle roller bearings. In this embodiment, two first bearing portions 201 are provided. Each first bearing portion 201 is pressed into and fixed to the outer side of the upper end and the outer side of the lower end of the first component 130, respectively, to provide axial support for the upper and lower ends of the first component 130. The first bearing portion 201 on the lower end side of the first component 130 is disposed in such that it contacts the upper surface of the first flange-shaped portion 192 on the inner side of the main body portion 191. The first bearing portion 201 on the upper end side of the first component 130 is disposed in such that it contacts the lower surface of the second flange-shaped portion 193 on the inner side of the main body portion 191. As a result, the movement of the first component 130 in the Z direction relative to the first limiting component 190 is restricted, and the first component 130 is kept able to rotate relative to the first limiting component 190.

[0040] The second bearing portion 202 is disposed between the second component 150 and the first limiting component 190. The second bearing portion 202 holds the second component 150 so that it can rotate relative to the first limiting component 190 about the rotation axis AX. The second bearing portion 202 is constructed 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 pressed into and fixed to the inner side of the upper end and the inner side of the lower end of the second component 150, respectively, providing axial support for the upper and lower ends of the second component 150. The second bearing portion 202 on the lower end side of the second component 150 is disposed in contact with the upper surface of the first flange-like portion 192 on the outer side of the main body portion 191. The second bearing portion 202 on the upper end side of the second component 150 is disposed in contact with the lower surface of the second flange-like portion 193 on the outer side of the main body portion 191. As a result, the movement of the second component 150 in the Z direction relative to the first limiting component 190 is restricted, and the second component 150 is kept able to rotate relative to the first limiting component 190.

[0041] Figure 5 This is the first explanatory diagram of the torque transmission mechanism 100. Figure 5 The diagram 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 The diagram shows the case where the outer circumferential surface 131t overlaps with the inner circumferential surface 151t. Furthermore, in... Figure 5 In the diagram, each of the first limiting parts 199 is schematically shown by dashed lines. Furthermore, in... Figure 5In the image, each of the first rolling components 170 is schematically shown by shading.

[0042] exist Figure 5 The figure shows the angle θ in the outer circumferential surface 131 and the inner circumferential surface 151. The angle θ becomes larger as it moves towards the circumferential direction DC. Figure 5 The 0-degree angular position A0 and the 360-degree angular position A360 shown are at the same location. In this embodiment, the limiting part 199A is located at angular position A0. Figure 5 In order to facilitate understanding of the technology, the rolling member 170A and the limiting part 199A are shown near the angular position A0 and the angular position A360, respectively. However, in reality, there is only one rolling member 170A and one limiting part 199A.

[0043] exist Figure 5 In the diagram, a first groove 132 is shown by thick lines. The first groove 132 has a closed ring shape that surrounds the outer circumferential surface 131 along the circumferential direction DC. The first groove 132 as a whole has a periodic wave shape that reciprocates in the Z direction on the outer circumferential surface 131 and propagates along the circumferential direction DC. That is, when the first groove 132 is considered as a wave, the propagation direction of the first groove 132 is along the circumferential direction DC, and the vibration direction 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 a peak 132m and a trough 132v. The peak 132m and the trough 132v have sharp shapes. The positions of each peak 132m in the Z direction are 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 valley corresponds to a turning point in the aforementioned sawtooth shape. It should be noted that in this embodiment, the peak is located on the +Z direction side of the valley. In other embodiments, the positional relationship between the peak and valley may be reversed.

[0044] The second groove 152 has a closed ring shape that surrounds the inner circumferential surface 151 along the circumferential direction DC. The second groove 152 as a whole has a periodic wave shape that reciprocates in the Z direction on the inner circumferential surface 151 and propagates along the circumferential direction DC. That is, when the second groove 152 is considered as a wave, the propagation direction of the second groove 152 is along the circumferential direction DC, and the vibration direction of the second groove 152 is 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 twelve periods. That is, the second groove 152 has twelve peaks 152m and twelve valleys 152v. The peaks 152m and valleys 152v have pointed shapes. The positions of each peak 152m in the Z direction are approximately the same, and are also approximately the same as the positions of each peak 132m in the Z direction. Furthermore, the positions of each valley 152v in the Z direction are approximately the same, and are also approximately the same as the positions of each valley 132v in the Z direction. That is, 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.

[0045] In this embodiment, in the torque transmission mechanism 100, either the first component 130 or the second component 150 serves as an input shaft, and the other serves as an output shaft. The operation of the torque transmission mechanism 100 when the first component 130 serves as an input shaft will be described below.

[0046] Figure 6 This is the second explanatory diagram of the torque transmission mechanism 100. Figure 6 It shows from Figure 5 The state begins when the first component 130, acting as the input shaft, rotates by an angle θ1 in the circumferential direction DC around the rotation axis AX. Figure 6 In the example, the rotation angle θ1 is 60 degrees.

[0047] like Figure 6 As shown, by rotating the first component 130 around the rotation axis AX, each first rolling component 170 rolls within the first groove 132 and the second groove 152. Specifically, by rotating the first component 130, the first rolling component 170 rolls in path Pt1 within the first groove 132. Path Pt1 is the path whose length in the circumferential direction DC corresponds to the rotation angle θ1. Specifically, path Pt1 is as follows: in the first groove 132, the position of the first rolling component 170 before the rotation of the first component 130 begins is set as the starting point S1, and the position after advancing an amount corresponding to the rotation angle θ1 in the circumferential direction DC from the starting point is set as the ending point E1. Figure 6In the diagram, path Pt1 is shown as an example of path Pt1, indicated by the shading of the dot pattern regarding rolling member 170A. When the first rolling member 170 rolls in path Pt1, its movement about the rotation axis AX is restricted, so that the first rolling member 170 moves only in the Z direction along with the first groove 132. As a result, the circumferential DC position of the first rolling member 170 does not change, while its Z-direction position changes according to the Z-direction position of path Pt1. Furthermore, the first rolling member 170, by moving in the Z direction and rolling in path Pt2 within the second groove 152, transmits torque to the second member 150 via the second groove 152, causing the second member 150 to rotate about the rotation axis AX. Path Pt2 is a path such that the change in the rotation axis AX position of the first rolling member 170 when passing through path Pt2 is the same as the change in the rotation axis AX position of the first rolling member 170 when passing through path Pt1. Figure 6 In the diagram, path Pt2 is shown as an example of path Pt2, indicated by the shading of the dot pattern. The result is that the second component 150 rotates about the rotation axis AX by the amount of rotation angle θ2 corresponding to the length of the circumferential DC of path Pt2, i.e., the length of the circumferential DC between the starting point S2 and the ending point E2 of path Pt2. The ratio of rotation angle θ2 to 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. That is, the reduction ratio RR1a in this case is equivalent to the value obtained by dividing period T1 by period T2. It should be noted that it can also be said that... Figure 6 As indicated by the white arrow, the first rolling component 170A moves relative to the first component 130 and the second component 150 in the first groove 132 and the second groove 152 in the opposite direction of rotation of the first component 130 and the second component 150.

[0048] The operation of the torque transmission mechanism 100 when the second component 150 is used as the input shaft is substantially the same as the operation of the torque transmission mechanism 100 when the first component 130 is used as the input shaft. In this case, the first rolling component 170 rolls within the first groove 132 due to the rotation of the second component 150, thereby transmitting torque to the first component 130 via the first groove 132. Furthermore, the reduction ratio RR1b in this case is equivalent 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 component 150 is accelerated and output via the first component 130.

[0049] like Figure 5As shown, when viewed along the radial direction DR, each of the first rolling components 170 is positioned at the intersection position CP where the first groove 132 and the second groove 152 intersect. The intersection position CP includes a first intersection position CP1, a second intersection position CP2, a third intersection position CP3, and a fourth intersection position CP4. The first intersection position CP1 is the position where the first positive portion P1 intersects with the second positive portion P2. The first positive portion P1 is the portion of the first groove 132 extending in the forward direction from the valley 132v toward the peak 132m toward the circumferential direction DC. The second positive portion P2 is the portion of the second groove 152 extending in the forward direction from the valley 152v toward the peak 152m toward the circumferential direction DC. The second intersection position CP2 is the position where the first negative portion N1 intersects with the second negative portion N2. The first negative portion N1 is the portion of the first groove 132 extending in the forward direction from the peak 132m toward the valley 132v toward the circumferential direction DC. The second negative portion N2 is the portion of the second groove 152 that extends circumferentially DC from the peak 152m toward the valley 152v. The third intersection position CP3 is the location where the first positive portion P1 intersects with the second negative portion N2. The fourth intersection position CP4 is the location where the first negative portion N1 intersects with the second positive portion P2. It should be noted that both the first positive portion P1 and the first negative portion N1 include the apex of the peak 132m and the apex of the valley 132v. Furthermore, both the second positive portion P2 and the second negative portion N2 include the apex of the peak 152m and the apex of the valley 152v.

[0050] In this embodiment, each of the first rolling components 170 is disposed at a first intersection position CP1 or a second intersection position CP2. As a result, the rotation directions of the first component 130 and the second component 150 are the same. It should be noted that in other embodiments, each of the first rolling components 170 may also be disposed at a third intersection position CP3 or a fourth intersection position CP4. In this case, the rotation directions of the first component 130 and the second component 150 are opposite to each other.

[0051] According to the torque transmission mechanism 100 of this embodiment described above, the first rolling member 170, disposed 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, and 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 pin for torque transmission.

[0052] 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 method, the rotational speed can be reduced between the first component 130 and the second component 150 based on 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 can be reduced between the first component 130 and the second component 150 based on the difference between the period T1 of the first groove 132 and the period T2 of the second groove 152. Furthermore, in this embodiment, by arbitrarily varying the combination of periods T1 and T2, various reduction ratios can be achieved with a high degree of freedom.

[0053] Furthermore, in this embodiment, the first rolling member 170 is spherical. Therefore, the first rolling member 170 can roll more smoothly within the first groove 132 and the second groove 152. As a result, wear on the first member 130, the second member 150, the first rolling member 170, and the first limiting member 190 can be suppressed.

[0054] Furthermore, in this embodiment, the first rolling member 170 includes one rolling member 170A and another rolling member 170B. Thus, torque can be transmitted between the first member 130 and the second member 150 using the rolling members 170A and 170B. Therefore, for example, the load on each of the first rolling members 170 can be reduced compared to a configuration where the rolling member 170A is provided.

[0055] Furthermore, as in this embodiment, since multiple first rolling members 170 are provided, the rotational direction of the second member 150 relative to the first member 130, or the rotational direction of the first member 130 relative to the second member 150, can be easily and uniquely determined. Specifically, for example, when only rolling member 170A is provided, as the first member 130, which serves as the input shaft, rotates, causing the rolling member 170A to approach the peak 152m and valley 152v of the second groove 152, the rolling member 170A can advance either to one side of the circumferential direction DC within the second groove 152. As a result, the second member 150 can rotate either in the forward direction of the circumferential direction DC or in the reverse direction of the circumferential direction DC, thus creating the possibility of the second member 150 reciprocating within 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. It should be noted that this phenomenon can also occur when the second member 150 is used as the input shaft. On the other hand, when a rolling member 170B is provided in addition to the rolling member 170A, for example, when the rolling member 170A is close to the peak 152m and the valley 152v, the rolling member 170B can be positioned outside the peak 152m and the valley 152v of the second groove 152. In this case, by uniquely determining the moving direction of the rolling member 170B within the second groove 152, the moving direction of the rolling member 170B within the second groove 152 and the rotation direction of the second member 150 are also uniquely determined.

[0056] Furthermore, in this embodiment, by means of the first bearing portion 201 disposed between the first component 130 and the first limiting component 190, the first component 130 can rotate more smoothly relative to the first limiting component 190.

[0057] Furthermore, in this embodiment, by configuring the second bearing portion 202 between the second component 150 and the first limiting component 190, the second component 150 can rotate more smoothly relative to the first limiting component 190.

[0058] 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 each position within the second groove 152, the Z-direction movement of the first rolling member 170 per unit rotation angle of the first member 130 and the second member 150 is approximately constant. Thus, the first member 130 can rotate more stably relative to the second member 150, or the second member 150 can rotate 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. Furthermore, compared to a sawtooth shape with arc-shaped peaks and valleys, such as a sine curve shape, the first groove 132 and the second groove 152 can further improve the torque transmission efficiency in the peaks and valleys. As a result, torque can be transmitted more efficiently between the first member 130 and the second member 150.

[0059] B. Second implementation method:

[0060] Figure 7 This is a schematic cross-sectional view showing a simplified structure of the torque transmission mechanism 100b in the second embodiment. Figure 8 yes Figure 7 Sectional view of VIII-VIII. Figure 7 The cross-sections of the torque transmission mechanism 100b along the X and Y directions are shown. Figure 8 Cross-sections of the torque transmission mechanism 100b along the X and Z directions are shown. Figure 7 and Figure 8 As shown, in this embodiment, unlike the first embodiment, a third groove 162 is provided on the outer peripheral surface 161 of the second component 150b. Furthermore, the torque transmission mechanism 100b also includes a third component 230, one or more second rolling components 250, and a second limiting component 270. Points in the torque transmission mechanism 100b of this embodiment that are not specifically described are the same as in the first embodiment. It should be noted that... Figure 7 and Figure 8 The example shown has four first rolling members 170 and four second rolling members 250. Furthermore, in... Figure 7 and Figure 8 In the diagram, the first slot 132, the second slot 152, and the third slot 162 are schematically shown using dashed lines. Furthermore, in... Figure 7 and Figure 8 In this paper, components such as the first bearing section 201 and the second bearing section 202 are appropriately omitted.

[0061] The third groove 162 has a sawtooth shape extending around the rotation axis AX on the outer peripheral surface 161. The third groove 162 is configured in a manner substantially the same as that of the first groove 132. In this embodiment, the third groove 162 has an annular shape that closes around the outer peripheral surface 161 in the circumferential direction DC. The third groove 162 as a whole has a periodic wave shape that reciprocates along the rotation axis AX on the outer peripheral surface 161 and advances along the circumferential direction DC. Specifically, the third groove 162 has a triangular wave shape. The period T3 of the third groove 162 can be the same as or different from the periods T1 and T2. In this embodiment, the period T3 is 1. The positions of the peaks of the third groove 162 in the Z direction are substantially the same. Furthermore, the positions of the valleys of the third groove 162 in the Z direction are substantially the same.

[0062] like Figure 7 As shown, the third component 230 has an annular shape surrounding the second component 150b. That is, the inner diameter of the third component 230 is larger than the outer diameter of the second component 150. In this embodiment, among the various parts of the torque transmission mechanism 100b, the third component 230 is arranged on the outermost side in the horizontal direction. The third component 230 is configured to be rotatable about the rotation axis AX. Figure 7 and Figure 8 As shown, the third component 230 has an inner peripheral surface 231. A fourth groove 232 is provided on the inner peripheral surface 231.

[0063] The fourth groove 232 has a sawtooth shape extending around the rotation axis AX on the inner circumferential surface 231. The fourth groove 232 is constructed in a manner substantially the same as the second groove 152. The fourth groove 232 has an annular shape that closes around the circumferential direction DC on the inner circumferential surface 231. The fourth groove 232 as a whole has a periodic wave shape that reciprocates along the rotation axis AX on the inner circumferential surface 231 and advances along the circumferential direction DC. Specifically, the fourth groove 232 has a triangular wave shape. The fourth groove 232 has a period T4 different from the period T3. That is, the number of peaks and valleys in the third groove 162 is different from the number of peaks and valleys in the fourth groove 232. The period T4 can be the same as or different from the periods T1 and T2. In this embodiment, the relationship between the magnitudes of periods T4 and T3 is the same as the relationship between the magnitudes of periods T2 and T1. Specifically, in this embodiment, the period T4 is 12. The Z-direction positions of the peaks of the fourth groove 232 are approximately the same, and are also approximately the same as the Z-direction positions of the peaks of the third groove 162. Furthermore, the Z-direction positions of the valleys of the fourth groove 232 are approximately the same, and are also approximately the same as the Z-direction positions of the valleys of the third groove 162.

[0064] The second rolling member 250 is configured substantially the same as the first rolling member 170. The second rolling member 250 is disposed 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 is positioned at the intersection of the third groove 162 and the fourth groove 232 when viewed along the radial direction of the torque transmission mechanism 100b, and rolls within the third groove 162 and the fourth groove 232. In this embodiment, the second rolling member 250, like the first rolling member 170, has a spherical shape. The second rolling member 250 transmits torque between the second member 150b and the third member 230.

[0065] The second limiting member 270 is configured substantially the same as the first limiting member 190. In this embodiment, the second limiting member 270 has a hollow cylindrical shape as a whole. The second limiting member 270 is disposed between the second member 150b and the third member 230. The second limiting 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. It should be noted that, for example, bearing portions substantially the same as the first bearing portion 201 and the second bearing portion 202 may be disposed between the second limiting member 270 and the second member 150b, and between the second limiting 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 relative to the second limiting member 270 about the rotation axis AX.

[0066] In this embodiment, similar to the first embodiment, deceleration is achieved between the first component 130 and the second component 150b via the first rolling component 170. Furthermore, in this embodiment, deceleration is achieved between the second component 150b and the third component 230 via the second rolling component 250. The operation of the third component 230 relative to the second component 150b is substantially the same as the operation of the second component 150b relative to the first component 130. For example, when the first component 130 is used as an input shaft, a deceleration ratio RR1a is achieved between the first component 130 and the second component 150b, and a deceleration ratio RR2a is achieved between the second component 150b and the third component 230. The deceleration ratio RR2a is equivalent to the value obtained by dividing the period T3 by the period T4. As a result, a deceleration ratio RR3a is achieved between the first component 130, which is the input shaft, and the third component 230, which is the output shaft. The deceleration ratio RR3a is equivalent to the product of the deceleration ratios RR1a and RR2a. Furthermore, when the third component 230 is used as the input shaft, a reduction ratio RR2b is achieved between the third component 230 and the second component 150b, and a reduction ratio RR1b is achieved between the second component 150b and the first component 130. The reduction ratio RR2b is equivalent 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 component 230, which is the input shaft, and the first component 130, which is the output shaft. The reduction ratio RR3b is equivalent to the product of the reduction ratios RR1b and RR2b. That is, in this case, the rotation input to the torque transmission mechanism 100b is accelerated and output.

[0067] The torque transmission mechanism 100b according to the second embodiment described above is configured such that the second rolling member 250 can roll within the third groove 162 and the fourth groove 232. The second rolling member 250 is disposed within the third groove 162 provided on the outer peripheral surface 161 of the second member 150b, and within the fourth groove 232 provided on the inner peripheral surface 231 of the third member 230 surrounding the second member 150b. 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 is different from the number of peaks and valleys in the fourth groove 232. Therefore, the rotational speed can be reduced in stages between the first member 130 and the second member 150b, and between the second member 150b and the third member 230. Thus, for example, the period of the second groove 152 and the fourth groove 232 is not excessively increased, and a higher reduction ratio can be achieved. As a result, for example, the increase in the period of the second groove 152 and the fourth groove 232 can be prevented from leading to an increase in the size of the second component 150b and the third component 230. Therefore, the torque transmission mechanism 100b can be configured in a more space-efficient manner, and a higher reduction ratio can be achieved. Furthermore, for example, the increase in the period of the second groove 152 and the fourth groove 232 can be prevented from leading to an excessive reduction in the size of the first rolling component 170 and the second rolling component 250. Therefore, the decrease in the durability of the torque transmission mechanism 100b can be prevented, and a higher reduction ratio can be achieved. It should be noted that, in other embodiments, for example, a fourth component may be provided outside the third component 230 to further achieve staged deceleration.

[0068] C. Third implementation method:

[0069] Figure 9 This is a schematic cross-sectional view showing a simplified structure of the torque transmission mechanism 100c in the third embodiment. Figure 9 and Figure 8 The cross-sections of the torque transmission mechanism 100c along the X and Z directions are shown in a substantially similar manner. In this embodiment, unlike the first embodiment, a first corresponding groove 139 is provided on the outer peripheral surface 131c of the first component 130c. Furthermore, a second corresponding groove 159 is provided on the inner peripheral surface 151c of the second component 150c. One or more third rolling components 280 are disposed within the first corresponding groove 139 and the second corresponding groove 159. Additionally, the first limiting component 190 has a second limiting portion 205. Points in the torque transmission mechanism 100c of this embodiment not specifically described are the same as in the first embodiment.

[0070] The first corresponding groove 139 and the first groove 132 are arranged in the Z direction. In this embodiment, the first corresponding groove 139 is disposed on the +Z direction side of the first groove 132. The first corresponding groove 139 is a groove corresponding to the first groove 132 and has a sawtooth 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 valleys 139v as the first groove 132. 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 are opposite each other. It should be noted that, in the first component 130c, for example, the part provided with the first groove 132 and the part provided with the first corresponding groove 139 may be separately constructed, and the two parts that are fixedly stacked on top of each other may be used to construct the first component 130c.

[0071] The second corresponding groove 159 and the second groove 152 are arranged in the Z direction. In this embodiment, the second corresponding groove 159 is disposed on the +Z direction side of the second groove 152. The second corresponding groove 159 is a groove corresponding to the second groove 152 and has a sawtooth 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 152m and valleys 152v as the second groove 152. Furthermore, the number of peaks 139m and valleys 139v of the first corresponding groove 139 is different from the number of peaks 159m and valleys 159v of the second corresponding groove 159. In this embodiment, 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 are opposite each other. It should be noted that the second component 150c is constructed in a manner substantially similar to the first component 130c. For example, the portion provided with the second groove 152 and the portion provided with the second corresponding groove 159 are constructed separately.

[0072] 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, for example, substantially the same as the first rolling member 170. The third rolling member 280 and the first rolling member 170 transmit torque between the first member 130 and the second member 150, substantially the same. The second limiting member 205 allows movement of the third rolling member 280 along the rotation axis AX and limits movement of the third rolling member 280 about the rotation axis AX. The second limiting member 270 is configured, for example, substantially the same as the first limiting member 199. Specifically, in this embodiment, the first limiting member 190 has a slit portion 195c in the Z direction, extending from the first groove 132 and the second groove 152 to the first corresponding groove 139 and the second corresponding groove 159, through which the movement of the first rolling member 170 and the third rolling member 280 is permitted and limited. It should be noted that in other embodiments, for example, the first limiting part 199 and the second limiting part 205 may each have an independent slit portion, through which the movement of the first rolling member 170 and the third rolling member 280 is permitted and restricted.

[0073] In this embodiment, at least one first rolling member 170 is configured such that, when at least one third rolling member 280 is located at the valley 139v of the first corresponding groove 139, at least one first rolling member 170 is located at the peak 132m of the first groove 132. Furthermore, at least one first rolling member 170 is configured such that, when at least one third rolling member 280 is located at the valley 159v of the second corresponding groove 159, at least one first rolling member 170 is located at the peak 152m of the second groove 152. Figure 9 The diagram illustrates the following scenario: when one rolling member 170p of the first rolling member 170 is located at peaks 132m and 152m, one rolling member 280p of the third rolling member 280 is located at valleys 139v and 159v. Furthermore, the diagram illustrates the following scenario: when one rolling member 170q of the first rolling member 170 is located at valleys 132v and 152v, one rolling member 280q of the third rolling member 280 is located at peaks 139m and 159m. It should be noted that although the diagram is omitted, when rolling member 170p is located at valleys 132v and 152v, rolling member 280p is located at peaks 139m and 159m. Similarly, when rolling member 170q is located at peaks 132m and 152m, rolling member 280q is located at valleys 139v and 159v.

[0074] According to the torque transmission mechanism 100c in the third embodiment described above, the third rolling member 280 is configured to roll within a first corresponding groove 139 and a second corresponding groove 159. The third rolling member 280 is disposed within the first corresponding groove 139 on the outer peripheral surface 131c of the first member 130c and within the second corresponding groove 159 on the inner peripheral surface 151c of the second member 150c. 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. Thus, using the first rolling member 170 and the third rolling member 280, torque can be transmitted between the first member 130 and the second member 150. Therefore, the load on each rolling member can be reduced. It should be noted that in other embodiments, for example, two or more first corresponding grooves 139 may be provided in the first member 130, and two or more second corresponding grooves 159 may be provided in the second member 150.

[0075] 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 relative to each other in the rotation axis AX, suppressing the oscillation of the torque transmission mechanism 100c in 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 peak 132m of the first groove 132 faces the valley 139v of the first corresponding groove 139. Furthermore, the second groove 152 and the second corresponding groove 159 are arranged such that the peak 152m of the second groove 152 faces the valley 159v of the second corresponding groove 159. Thus, as... Figure 9 As shown, the first rolling member 170 and the third rolling member 280 can be arranged such that the first rolling member 170 and the third rolling member 280 are positioned at the same location in the X direction. As a result, as in this embodiment, for example, by arranging the pair of the first rolling member 170 and the third rolling member 280 within a slit 195c, the allowable and restricted movement of the pair of the first rolling member 170 and the third rolling member 280 can be achieved through the slit 195c. Thus, the oscillation of the torque transmission mechanism 100c in the rotation axis AX direction can be suppressed with a simpler structure.

[0076] D. Fourth Implementation Method:

[0077] Figure 10 This is a schematic cross-sectional view showing a simplified structure of the torque transmission mechanism 100d in the fourth embodiment. Figure 10 and Figure 8 , Figure 9The torque transmission mechanism 100d is shown in roughly the same cross-sections along the X and Z directions. In this embodiment, unlike the first embodiment, the torque transmission mechanism 100d includes a first deceleration section 101, a second deceleration section 102, and a connecting member 103. Points in the torque transmission mechanism 100d of this embodiment not specifically described are the same as in the first embodiment.

[0078] The first deceleration section 101 is configured similarly to the torque transmission mechanism 100 in the first embodiment. The second deceleration section 102 is configured substantially the same as the first deceleration section 101. The second deceleration section 102 includes a fourth component 330, a fifth component 350, one or more fourth rolling components 370, and a third limiting component 390. It should be noted that, in other embodiments, for example, each part of the second deceleration section 102 can be interchanged with each part of the first deceleration section 101. The second deceleration section 102 and the first deceleration section 101 are arranged in the Z direction. As a result, the fourth component 330 and the fifth component 350 are arranged in the Z direction with the first component 130 and the second component 150. Specifically, in this embodiment, the second deceleration section 102 is located on the +Z direction side of the first deceleration section 101, so that the fourth component 330 and the fifth component 350 are arranged on the +Z direction side of the first component 130 and the second component 150.

[0079] The fourth component 330 corresponds to the first component 130 in the first deceleration unit 101, and is configured in a manner substantially similar to the first component 130. The fourth component 330 has a cylindrical shape. The fourth component 330 is configured to rotate about the rotation axis AX. The fourth component 330 has an outer peripheral surface 331, on which a fifth groove 332 is provided. The fifth groove 332 is configured in a manner substantially similar to the first groove 132. The fifth groove 332 has a sawtooth shape that extends about the rotation axis AX and circumferentially surrounds the outer peripheral surface 131 in the circumferential direction DC. The fifth groove 332 is a periodic wave shape with peaks 332m and valleys 332v, and has a period T5. The period T5 may be the same as or different from the 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 peaks 132m of the first groove 132 and the valleys 332v of the fifth groove 332 are opposite each other.

[0080] The fifth component 350 corresponds to the second component 150 in the first deceleration section 101, and is configured in a manner substantially similar to the second component 150. The fifth component 350 has an annular shape surrounding the fourth component 330. The fifth component 350 is configured to rotate about the rotation axis AX. The fifth component 350 has an inner circumferential surface 351, on which a sixth groove 352 is provided. The sixth groove 352 is configured in a manner substantially similar to the second groove 152. The sixth groove 352 has a serrated shape extending about the rotation axis AX and circumferentially surrounding the inner circumferential surface 351 in the circumferential direction DC. The sixth groove 352 is a periodic wave shape with peaks 352m and valleys 352v. 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. That is, the period T6 of the sixth groove 352 is different from the period T5 of the fifth groove 332. The period T6 can be the same as or different from the periods T1 and T2. In this embodiment, the relationship between the periods T6 and T5 is the same as the relationship between the periods T2 and T1. Specifically, the period T6 in this embodiment is 12. In this embodiment, the second groove 152 and the sixth groove 352 are arranged such that the peak 152m of the second groove 152 and the valley 352v of the sixth groove 352 are opposite each other.

[0081] The fourth rolling member 370 corresponds to the first rolling member 170 in the first deceleration unit 101, and is configured, for example, substantially the same as the first rolling member 170. The fourth rolling member 370 is disposed in the fifth groove 332 and the sixth groove 352, and is configured to be able to roll in the fifth groove 332 and the sixth groove 352.

[0082] The third limiting member 390 corresponds to the first limiting member 190 in the first deceleration unit 101, and is configured in a manner substantially the same as the first limiting member 190. The third limiting member 390 is disposed between the fourth member 330 and the fifth member 350. The third limiting 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 limiting member 390, for example, similar to the first limiting member 190, achieves both allowing and restricting the movement of the fourth rolling member 370 through a slit.

[0083] The connecting member 103 connects the first deceleration unit 101 and the second deceleration unit 102. More specifically, the connecting member 103 connects the second member 150 and the fourth member 330 so that they can rotate about the rotation axis AX. In this embodiment, the connecting member 103 is disposed 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.

[0084] In this embodiment, substantially similar to the second embodiment, rotational speeds can be achieved in stages between the first component 130 and the second component 150 in the first deceleration section 101, and between the fourth component 330 and the fifth component 350 in the second deceleration section 102. Specifically, for example, when the first component 130 is used as an input shaft, a reduction ratio RR1a is achieved between the first component 130 and the second component 150 in the first deceleration section 101. At this time, the rotation of the second component 150 is transmitted to the fourth component 330 via the connecting component 103. Furthermore, in the second deceleration section 102, deceleration is achieved between the fourth component 330 and the fifth component 350 via the fourth rolling component 370. In this case, the reduction ratio RR4a achieved between the fourth component 330 and the fifth component 350 is equivalent 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 component 130, which serves as an input shaft, and the fifth component 350, which serves as an output shaft. The reduction ratio RR5a is equivalent to the product of reduction ratios RR1a and RR4a. Furthermore, when the fifth component 350 is used as the input shaft, a reduction ratio RR4b is achieved between the fifth component 350 and the fourth component 330 in the second reduction section 102, and a reduction ratio RR1b is achieved in the first reduction section 101. As a result, a reduction ratio RR5b is achieved between the fifth component 350, which serves as the input shaft, and the first component 130, which serves as the output shaft. The reduction ratio RR5b is equivalent to the product of reduction ratios RR1b and RR4b. That is, in this case, the rotation input to the torque transmission mechanism 100d is accelerated and output.

[0085] In this embodiment, at least one first rolling member 170 is configured such that, when at least one fourth rolling member 370 is located at the valley 332v of the fifth groove 332, at least one first rolling member 170 is located at the peak 132m of the first groove 132. Furthermore, the first rolling member 170 is configured such that, when at least one fourth rolling member 370 is located at the valley 352v of the sixth groove 352, the first rolling member 170 is located at the peak 152m of the second groove 152. Figure 10The diagram illustrates the following scenario: when one rolling member 170p, included in the first rolling member 170, is located at peaks 132m and 152m, one rolling member 370p, included in the fourth rolling member 370, is located at valleys 332v and 352v. Furthermore, the diagram illustrates the following scenario: when one rolling member 170q, included in the first rolling member 170, is located at valleys 132v and 152v, one rolling member 370q, included in the fourth rolling member 370, is located at peaks 332m and 352m. It should be noted that although the diagram is omitted, when rolling member 170p is located at valleys 132v and 152v, rolling member 370p is located at peaks 332m and 352m. Similarly, when rolling member 170q is located at peaks 132m and 152m, rolling member 370q is located at valleys 332v and 352v.

[0086] According to the torque transmission mechanism 100d in the fourth embodiment described above, the first deceleration unit 101 and the second deceleration unit 102 are arranged in the Z direction. The second component 150 of the first deceleration unit 101 and the fourth component 330 of the second deceleration unit 102 are connected by the connecting component 103 so that they can rotate about the rotation axis AX. In the second deceleration unit 102, the fourth rolling component 370 disposed in the fifth groove 332 of the fourth component 330 and the sixth groove 352 of the fifth component 350 is configured to roll in the fifth groove 332 and the sixth groove 352. The fourth rolling component 370 is allowed to move along the rotation axis AX in the fifth groove 332 and the sixth groove 352, and is also allowed to move about the rotation axis AX. 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 component 130 and the second component 150, and between the fourth component 330 and the fifth component 350, allowing for a more space-efficient configuration of the torque transmission mechanism 100d in the radial direction and achieving a higher reduction ratio. It should be noted that in other embodiments, for example, other reduction units may be connected to the first reduction unit 101 and the second reduction unit 102 to further achieve staged deceleration. Furthermore, for example, staged deceleration can be further achieved by combining the structures of the third and fourth embodiments.

[0087] Furthermore, in this embodiment, when the rolling member 170p is located at the peaks 132m and 152m, the rolling member 370p 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 rotation axis AX, suppressing the oscillation of the torque transmission mechanism 100d in the rotation axis AX caused by the movement of the first rolling member 170 and the fourth rolling member 370.

[0088] E. Fifth implementation method:

[0089] Figure 11 This is a perspective view showing a simplified structure of the torque transmission mechanism 100e in the fifth embodiment. Figure 12 This is an exploded perspective view showing the simplified structure of the torque transmission mechanism 100e. Figure 13 yes Figure 11 Sectional view XIII-XIII. Figure 14 yes Figure 11 The XIV-XIV sectional view. In this embodiment, the structure of the first limiting member 190e differs from that in the first embodiment. Points in the torque transmission mechanism 100e of this embodiment that are not specifically described are the same as in the first embodiment.

[0090] like Figure 11 , Figure 12 ,as well as Figure 14 As shown, the first limiting member 190e in this embodiment includes a columnar member 211, a first annular member 215, and a second annular member 220.

[0091] The first annular component 215 has an annular shape. The first annular component 215 is configured such that its axial direction is along the Z-direction. A plurality of first through holes 216 are provided in the first annular component 215. The first through holes 216 penetrate the first annular component 215 in the Z-direction. In this embodiment, ten first through holes 216 are provided in the first annular component 215.

[0092] The second annular component 220 has an annular shape. The second annular component 220 is arranged such that its axial direction is along the Z-direction. A plurality of second through holes 221 are provided in the second annular component 220. The second through holes 221 penetrate the second annular component 220 in the Z-direction. In this embodiment, ten second through holes 221 are provided in the second annular component 220 corresponding to ten first through holes 216.

[0093] In this embodiment, ten columnar members 211 are provided corresponding to the ten first through holes 216 and the ten second through holes 221. Each columnar member 211 has a cylindrical shape as a whole. The columnar members 211 are arranged such 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 holes 216 and the second through holes 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 holes 216 and the second through holes 221. Each columnar member 211 is inserted into the second through holes 221 and the first through holes 216 from the +Z direction side. That is, the shaft portion 213 of each columnar member 211 is respectively disposed within the first through holes 216 and the second through holes 221. Furthermore, the head 212 of each columnar member 211 is positioned on the +Z direction side of the second annular member 220. Additionally, the lower end of each columnar member 211 is fixed to the first annular member 215 via a fixing member 225 and a first through hole 216. The fixing member 225 is, for example, composed of bolts and washers. With this structure, the columnar members 211 are horizontally connected to each other via the first annular member 215 and the second annular member 220.

[0094] like Figure 12 and Figure 14 As shown, the columnar members 211 are connected to each other horizontally, thereby forming openings between adjacent columnar members 211 in the circumferential DC direction. In this embodiment, the first rolling members 170 are arranged in five such openings Op. The opening width in the circumferential DC direction of each opening Op is slightly larger than the diameter of the first rolling member 170. The opening length in the Z direction of each opening Op is larger than the opening width of each opening Op. The openings Op, in a manner substantially similar to the slits 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 about the rotation axis AX. Specifically, the movement of the first rolling member 170 about the rotation axis AX is restricted by the columnar members 211, which divide the openings Op. Thus, in this embodiment, the first restricting member 190e enables and restricts the movement of each first rolling member 170 through the openings Op. It should be noted that the first limiting member 190e and the first limiting member 190 described in the first embodiment are the same in that they allow and limit the movement of the first rolling member 170 by means of a slot-shaped opening extending in the Z direction.

[0095] According to the torque transmission mechanism 100e in the fifth embodiment described above, it is also possible to reduce the rotational speed between the first component 130 and the second component 150 via the first rolling component 170, according to the first groove 132 and the second groove 152, without using a pin for torque transmission.

[0096] It should be noted that the same structure as the first limiting member 190e in the fifth embodiment can also be applied to the second limiting member 270 described in the second embodiment and the third limiting member 390 described in the fourth embodiment.

[0097] F. Other implementation methods:

[0098] (F-1) In the above embodiments, the first rolling member 170 is spherical. In this regard, the first rolling member 170 may be able to roll within the first groove 132 and the second groove 152, or it may not be spherical. For example, the first rolling member 170 may also have a curved surface shape different from that of a sphere, which enables it to roll within the first groove 132 and the second groove 152.

[0099] (F-2) In the above embodiments, a plurality of first rolling members 170 are provided. However, the number of first rolling members 170 can also be one. Furthermore, as long as torque transmission based on the torque transmission mechanism 100 can be achieved, and each first rolling member 170 can be arranged in the first slot 132 and the second slot 152, the number of first rolling members 170 and their arrangement can be arbitrary. For example, the number of first rolling members 170 can be two or more and four or less, or even six or more. Similarly, the number and arrangement of the second rolling member 250, the third rolling member 280, and the fourth rolling member 370 can also be arbitrary. Furthermore, the number of the first rolling member 170, the second rolling member 250, the third rolling member 280, and the fourth rolling member 370 can be the same or different.

[0100] (F-3) In the above embodiments, a first bearing portion 201 is provided; however, a first bearing portion 201 may not be provided. Similarly, a second bearing portion 202 may not be provided.

[0101] (F-4) In the above embodiments, the period T1 of the first slot 132 is less than the period T2 of the second slot 152; however, the period T1 may be greater than the period T2. In this case, when the first component 130 is used as an input shaft, acceleration is achieved between the first component 130 and the second component 150. Furthermore, when the second component 150 is used as an input shaft, deceleration is achieved between the second component 150 and the first component 130. Similarly, the period T3 may be greater than the period T4. Similarly, the period T5 may be greater than the period T6.

[0102] (F-5) In the above embodiment, the first groove 132 and the second groove 152 have a triangular wave shape, but they may not have a triangular wave shape. For example, the first groove 132 and the second groove 152 may also have a sine curve shape, a sawtooth wave shape, or a sawtooth shape. Similarly, the third groove 162, the fourth groove 232, the fifth groove 332, and the sixth groove 352 may not have a triangular wave shape.

[0103] (F-6) In the above embodiments, 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, but they can also 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 may not be configured as a speed reduction device.

[0104] For example, Figure 15 This is an explanatory diagram of torque transmission mechanism 100f, which is the first example of a torque transmission mechanism in other embodiments. Figure 16 This is an explanatory diagram of a torque transmission mechanism 100g, which is a second example of a torque transmission mechanism in other embodiments. Figure 15 and Figure 16 In, with Figure 5 The outer circumferential surface 131t and the inner circumferential surface 151t are shown in roughly the same manner. Figure 15 and Figure 16 In the example, the number of peaks 132m and valleys 132v in the first groove 132 is the same as the number of peaks 152m and valleys 152v in the second groove 152f, which is one. Furthermore, in Figure 15 and Figure 16 In the example, the first rolling member 170 includes rolling member 170A and rolling member 170B, and the first limiting member 199 includes limiting member 199A and limiting member 199B. Figure 15In the example, when the outer peripheral surface 131t and the inner peripheral surface 151t are viewed along the radial direction DR, the first component 130 and the second component 150f are arranged such that the peak 132m of the first groove 132 and the valley 152v of the second groove 152f are positioned at the same location in the circumferential direction DC, that is, the first groove 132 and the second groove 152f are in opposite phase. Therefore, when rotation is input to one of the first component 130 and the second component 150f, rotation in the opposite direction to the input rotation can be output from the other. Furthermore, as... Figure 16 As shown, when observing the outer circumferential surface 131t and the inner circumferential surface 151t along the radial direction DR, the first component 130 and the second component 150f can be arranged in such a way that the peaks 132m of the first groove 132 and the peaks 152m of the second groove 152f are positioned at the same position in the circumferential direction DC, that is, in such a way that the first groove 132 and the second groove 152f are in phase. It should be noted that in Figure 16 In the diagram, for ease of understanding, the first slot 132 and the second slot 152f are shown offset; however, in reality, the first slot 132 and the second slot 152f overlap. Therefore, when rotation is input to one of the first component 130 and the second component 150f, rotation in the same direction as the input rotation can be output from the other component 130 and the second component 150f. Thus, even if the periods T1 and T2 are the same, torque transmission can be achieved between the first component 130 and the second component 150f without using a pin for torque transmission. Furthermore, using the same first component 130, second component 150f, and first limiting component 190, a forward-rotation type torque transmission mechanism that outputs rotation in the same direction as the input rotation, and a reverse-rotation type torque transmission mechanism that outputs rotation in the opposite direction to the input rotation, can be easily constructed.

[0105] (F-7) In the third embodiment described above, the peak 132m of the first groove 132 is opposite to the valley 139v of the first corresponding groove 139, and the peak 152m of the second groove 152 is opposite to the valley 159v of the second corresponding groove 159. Alternatively, the peak 132m and valley 139v may not be opposite. Furthermore, the peak 152m and valley 159v may not be opposite. In this case, for example, the peak 132m and valley 139v may be opposite, while the peak 152m and valley 159v may not be opposite. Furthermore, for example, the peak 152m and valley 159v may be opposite, while the peak 132m and valley 139v may not be opposite. Similarly, in the fourth embodiment described above, the peak 132m of the first groove 132 and the valley 332v of the fifth groove 332 may not be opposite. Furthermore, the peak 152m of the second groove 152 and the valley 352v of the sixth groove 352 may not be aligned.

[0106] Figure 17 This is an explanatory diagram of a torque transmission mechanism 100h, which is a third example of a torque transmission mechanism in other embodiments. Figure 17 In, with Figure 5 The outer peripheral surface 131t and the inner peripheral surface 151t are shown in roughly the same manner. In the torque transmission mechanism 100h, a first groove 132 and a first corresponding groove 139, as well as a second groove 152h and a second corresponding groove 159h, are provided in the same manner as in the third embodiment. Figure 17 In the example, 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 both two. Furthermore, in Figure 17 In the example, the first rolling member 170 includes rolling members 170A and 170B, and the first limiting member 199 includes limiting members 199A and 199B. Furthermore, the third rolling member 280 includes rolling members 280A and 280B, and the second limiting member 205 includes limiting members 205A and 205B. The limiting members 205A and 205B, substantially the same as the limiting members 199A and 199B, each have a slit extending in the Z direction. The limiting members 205A and 205B, through their respective slits, allow the rolling members 280A and 280B to move along the rotation axis AX, and limit the movement of the rolling members 280A and 280B about the rotation axis AX. Figure 17 In this example, unlike the third embodiment, the peak 132m and the valley 139v are not opposite, and the peak 152m and the valley 159v are not opposite. However, in Figure 17 In the example, similar to the third embodiment, when at least one third rolling member 280 is located at the valley 139v of the first corresponding groove 139, at least one first rolling member 170 is located at the peak 132m of the first groove 132. Furthermore, when at least one third rolling member 280 is located at the valley 159v of the second corresponding groove 159h, at least one first rolling member 170 is located at the peak 152m of the second groove 152. It should be noted that in... Figure 17 The diagram illustrates a scenario where rolling member 170A is located at peaks 132m and 152m, and rolling member 280A is located at valleys 139v and 159v. Therefore, similar to the third embodiment, it is possible to suppress the oscillation of torque transmission mechanism 100h in the Z-direction caused by the movement of the first rolling member 170 and the third rolling member 280. Thus, even when peaks 132m and 139v are not aligned, and peaks 152m and 159v are not aligned, oscillation of torque transmission mechanism 100h in the Z-direction can be suppressed.

[0107] G. Other methods:

[0108] This disclosure is not limited to the embodiments described above, and can be implemented in various ways without departing from its spirit. For example, this disclosure can also be implemented in the following ways. In order to solve part or all of the technical problems of this disclosure, or to achieve part or all of the effects of this disclosure, the technical features in the above embodiments corresponding to the technical features in the various methods described below can be appropriately replaced or combined. In addition, if a technical feature is not required to be described in this specification, it can be appropriately deleted.

[0109] (1) According to a first aspect of the present disclosure, a torque transmission mechanism is provided. The torque transmission mechanism comprises: a first component having a cylindrical shape, the first component being configured to rotate about a rotation axis and having an outer peripheral surface provided with a first groove, the first groove being a serrated shape extending about the rotation axis; a second component having an annular shape surrounding the first component, the second component being configured to rotate about the rotation axis and having an inner peripheral surface provided with a second groove, the second groove being a serrated shape extending about the rotation axis; one or more first rolling components disposed in the first groove and the second groove and configured to roll in the first groove and the second groove; and a first limiting component disposed between the first component and the second component, allowing the first rolling components to move along the rotation axis and limiting the movement of the first rolling components about the rotation axis.

[0110] According to this method, torque can be transmitted between the first and second components via a first rolling member, according to the first and second grooves, without using a pin for torque transmission.

[0111] (2) In the above-described manner, the first groove and the second groove may also be periodic wave shapes having one or more peaks and valleys, wherein the number of peaks and valleys in the first groove is different from the number of peaks and valleys in the second groove. According to this method, the rotational speed can be reduced between the first component and the second component based on the number of peaks and valleys in the first groove and the number of peaks and valleys in the second groove.

[0112] (3) In the above-described manner, the first rolling component may also be spherical. According to this method, the first rolling component can roll more smoothly.

[0113] (4) In the above-described manner, the first rolling component may also include one rolling component and another rolling component, and the first limiting component has: a limiting portion that allows the movement of the one rolling component along the rotation axis and limits the movement of the first rolling component about the rotation axis; and another limiting portion that allows the movement of the other rolling component along the rotation axis and limits the movement of the other rolling component about the rotation axis. According to this method, the load on each rolling component can be reduced.

[0114] (5) In the above-described manner, it may also include: a first bearing portion disposed between the first component and the first limiting component, which holds the first component so that it can rotate relative to the first limiting component. According to this method, the first component can rotate more smoothly relative to the first limiting component via the first bearing portion.

[0115] (6) In the above embodiment, it may also include: a second bearing portion disposed between the second component and the first limiting component, which holds the second component so that it can rotate relative to the first limiting component. According to this embodiment, the second component can rotate more smoothly relative to the first limiting component via the second bearing portion.

[0116] (7) In the above-described manner, a third groove may be provided on the outer peripheral surface of the second component, the third groove being a sawtooth shape extending about the rotation axis. The torque transmission mechanism further comprises: a third component having an annular shape surrounding the second component, the third component being configured to rotate about the rotation axis, and having an inner peripheral surface provided with a fourth groove, the fourth groove being a sawtooth shape extending about the rotation axis; one or more second rolling components disposed in the third groove and the fourth groove, and configured to roll in the third groove and the fourth groove; and a second limiting component disposed between the second component and the third component, allowing the second rolling component to move along the rotation axis and limiting the movement of the second rolling component about the rotation axis, the third groove and the fourth groove being periodic wave shapes having one or more peaks and valleys, the number of peaks and valleys in the third groove being different from the number of peaks and valleys in the fourth groove. According to this method, the rotational speed can be reduced in stages between the first and second components, and between the second and third components, thereby achieving a higher reduction ratio.

[0117] (8) In the above-described manner, a first corresponding groove is arranged on the outer peripheral surface of the first component along the rotational axis, with the first corresponding groove corresponding to the first groove. On the inner peripheral surface of the second component, a second corresponding groove is arranged on the rotational axis, with the second corresponding groove corresponding to the second groove. The torque transmission mechanism further comprises: one or more third rolling members disposed in the first corresponding groove and the second corresponding groove, and configured to roll within the first corresponding groove and the second corresponding groove. The first limiting member further allows the third rolling member to move along the rotational axis and limits the movement of the third rolling member about the rotational axis. According to this method, the load on each rolling member can be reduced.

[0118] (9) In the above-described manner, the first groove and the first corresponding groove may be periodic wave shapes having the same number of peaks and valleys, and the second groove and the second corresponding groove may be periodic wave shapes having the same number of peaks and valleys. At least one first rolling member is configured such that, when at least one third rolling member is located in the valley of the first corresponding groove, at least one first rolling member is located in the peak of the first groove, and when at least one third rolling member is located in the valley of the second corresponding groove, at least one first rolling member is located in the peak of the second groove. According to this method, the first rolling member and the third rolling member can move in opposite directions to each other in the rotational axis, and the oscillation of the torque transmission mechanism in the rotational axis caused by the movement of the first rolling member and the third rolling member in the rotational axis can be suppressed.

[0119] (10) In the above-described manner, the first groove and the first corresponding groove may be configured such that the peak of the first groove faces the valley of the first corresponding groove, and the second groove and the second corresponding groove may be configured such that the peak of the second groove faces the valley of the second corresponding groove. According to this method, the oscillation of the torque transmission mechanism in the rotational axis can be suppressed with a simpler structure.

[0120] (11) In the above embodiment, it may also include: a fourth component having a cylindrical shape, the fourth component being configured to rotate about the rotation axis, and having an outer peripheral surface provided with a fifth groove, the fifth groove being a serrated shape extending about the rotation axis; a fifth component having an annular shape surrounding the fourth component, the fifth component being configured to rotate about the rotation axis, and having an inner peripheral surface provided with a sixth groove, the sixth groove being a serrated shape extending about the rotation axis; a fourth rolling component disposed in the fifth groove and the sixth groove, and configured to be able to roll in the fifth groove and the sixth groove; and a third limiting portion. The system includes a component, disposed between the fourth and fifth components, allowing the fourth rolling component to move along the rotation axis and restricting its movement about the rotation axis; and a connecting component, connecting the second and fourth components so that they can rotate about the rotation axis. The fourth and fifth components are arranged with the first and second components in the direction of the rotation axis. The fifth and sixth grooves are periodic wave shapes having one or more peaks and valleys, and the number of peaks and valleys in the fifth groove is different from the number of peaks and valleys in the sixth groove. According to this method, the rotational speed can be reduced in stages between the first and second components and between the fourth and fifth components, allowing for a more space-efficient torque transmission mechanism in the radial direction and achieving a higher reduction ratio.

[0121] (12) In the above-described manner, the first groove and the fifth groove may each have the same number of peaks and valleys, and the second groove and the sixth groove may each have the same number of peaks and valleys. At least one of the first rolling members is configured such that, when at least one of the fourth rolling members is located in the valley of the fifth groove, at least one of the first rolling members is located in the peak of the first groove, and is configured such that, when at least one of the fourth rolling members is located in the valley of the sixth groove, at least one of the first rolling members is located in the peak of the second groove. According to this method, the first rolling member and the fourth rolling member can move in opposite directions to each other in the rotational axis, and the oscillation of the torque transmission mechanism in the rotational axis caused by the movement of the first rolling member and the fourth rolling member in the rotational axis can be suppressed.

[0122] (13) In the above-described manner, the first groove and the second groove may also have a triangular wave shape. According to this method, more efficient torque transmission can be achieved between the first component and the second component.

Claims

1. A torque transmission mechanism, characterized in that, have: The first component has a cylindrical shape, is configured to rotate about a rotation axis, and has an outer peripheral surface provided with a first groove, the first groove being a serrated shape extending about the rotation axis. The second component has an annular shape surrounding the first component, the second component is configured to be rotatable about the rotation axis, and has an inner circumferential surface provided with a second groove, the second groove being a serrated shape extending about the rotation axis. One or more first rolling members are disposed in the first groove and the second groove, and are configured to roll within the first groove and the second groove; and A first limiting member is disposed between the first member and the second member, allowing the first rolling member to move along the rotation axis and limiting the movement of the first rolling member about the rotation axis.

2. The torque transmission mechanism according to claim 1, characterized in that, The first groove and the second groove are periodic wave shapes with one or more peaks and valleys. The number of peaks and valleys in the first groove is different from the number of peaks and valleys in the second groove.

3. The torque transmission mechanism according to claim 1, characterized in that, The first rolling component has a spherical shape.

4. The torque transmission mechanism according to claim 1, characterized in that, The first rolling component includes one rolling component and another rolling component. The first limiting member has: a limiting portion that allows the movement of the first rolling member along the rotation axis and limits the movement of the first rolling member about the rotation axis; and another limiting portion that allows the movement of the other rolling member along the rotation axis and limits the movement of the other rolling member about the rotation axis.

5. The torque transmission mechanism according to claim 1, characterized in that, It also has: A first bearing portion is disposed between the first component and the first limiting component, holding the first component so that it can rotate relative to the first limiting component.

6. The torque transmission mechanism according to claim 1, characterized in that, It also has: A second bearing portion is disposed between the second component and the first limiting component, holding the second component so that it can rotate relative to the first limiting component.

7. The torque transmission mechanism according to claim 2, characterized in that, A third groove is provided on the outer peripheral surface of the second component. The third groove has a serrated shape extending around the rotation axis. The torque transmission mechanism also includes: The third component has an annular shape surrounding the second component, the third component is configured to be rotatable about the rotation axis, and has an inner circumferential surface provided with a fourth groove, the fourth groove being a serrated shape extending about the rotation axis. One or more second rolling members are disposed within the third groove and the fourth groove, and are configured to roll within the third groove and the fourth groove; and A second limiting member, disposed between the second member and the third member, allows movement of the second rolling member along the rotation axis and restricts movement of the second rolling member about the rotation axis. The third and fourth grooves are periodic wave shapes with one or more peaks and valleys. The number of peaks and valleys in the third groove is different from the number of peaks and valleys in the fourth groove.

8. The torque transmission mechanism according to claim 1, characterized in that, On the outer peripheral surface of the first component, a first corresponding groove and a first groove are arranged in the direction of the rotation axis, and the first corresponding groove has a sawtooth shape corresponding to the first groove. On the inner circumferential surface of the second component, a second corresponding groove and a second groove are arranged in the direction of the rotation axis, and the second corresponding groove has a sawtooth shape corresponding to the second groove. The torque transmission mechanism further includes one or more third rolling components, which are disposed in the first corresponding groove and the second corresponding groove, and are configured to roll within the first corresponding groove and the second corresponding groove. The first limiting component also allows the third rolling component to move along the rotation axis, while limiting the movement of the third rolling component about the rotation axis.

9. The torque transmission mechanism according to claim 8, characterized in that, The first groove and the first corresponding groove are periodic wave shapes with the same number of peaks and valleys, respectively. The second groove and the second corresponding groove are periodic wave shapes, each having the same number of peaks and valleys. At least one of the first rolling members is configured such that, when at least one of the third rolling members is located in the valley of the first corresponding groove, at least one of the first rolling members is located in the peak of the first groove, and when at least one of the third rolling members is located in the valley of the second corresponding groove, at least one of the first rolling members is located in the peak of the second groove.

10. The torque transmission mechanism according to claim 9, characterized in that, The first groove and the first corresponding groove are configured such that the peak of the first groove is opposite to the valley of the first corresponding groove. The second groove and the second corresponding groove are configured such that the peak of the second groove is opposite to the valley of the second corresponding groove.

11. The torque transmission mechanism according to claim 2, characterized in that, It also has: The fourth component has a cylindrical shape, is configured to rotate about the rotation axis, and has an outer peripheral surface provided with a fifth groove, the fifth groove being a serrated shape extending about the rotation axis; The fifth component has an annular shape surrounding the fourth component, the fifth component is configured to be rotatable about the rotation axis, and has an inner circumferential surface provided with a sixth groove, the sixth groove being a serrated shape extending about the rotation axis; A fourth rolling member is disposed in the fifth groove and the sixth groove, and is configured to be able to roll in the fifth groove and the sixth groove; A third limiting member, disposed between the fourth and fifth members, allows movement of the fourth rolling member along the rotation axis and limits movement of the fourth rolling member about the rotation axis; and A connecting component connects the second component and the fourth component so that they can rotate about the rotation axis. The fourth and fifth components are arranged in the direction of the rotation axis along with the first and second components. The fifth and sixth grooves are periodic wave shapes having one or more peaks and valleys. The number of peaks and valleys in the fifth groove is different from the number of peaks and valleys in the sixth groove.

12. The torque transmission mechanism according to claim 11, characterized in that, The first groove and the fifth groove each have the same number of peaks and valleys. The second groove and the sixth groove each have the same number of peaks and valleys. At least one of the first rolling members is configured such that, when at least one of the fourth rolling members is located in the valley of the fifth groove, at least one of the first rolling members is located in the peak of the first groove, and is configured such that, when at least one of the fourth rolling members is located in the valley of the sixth groove, at least one of the first rolling members is located in the peak of the second groove.

13. The torque transmission mechanism according to any one of claims 1 to 12, characterized in that, The first groove and the second groove have a triangular wave shape.

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