Bearing holding mechanism

Abstract

The invention provides a bearing holding mechanism. The durability of the bearing holding mechanism is improved by reducing the influence caused by the fastening of the restricting member. The invention relates to a bearing retention mechanism. A bearing holding mechanism according to an embodiment includes: a first member having an inner peripheral surface including a female screw portion; a second member inserted into the inner peripheral surface; a rolling member that rolls on a rolling surface formed on the second member; a crankshaft that is rotatably supported by the second member via the rolling member; and a restricting member that has a male thread portion that is threadingly fixed to the female thread portion of the first member, and that is supported by the first member and the second member.

Description

[0001] This application is a divisional application with an application date of August 15, 2019, application number 201910752837.4, and invention name “Bearing Retaining Mechanism”. Technical Field

[0002] The present invention relates to a bearing holding mechanism, and more particularly to a bearing holding mechanism applicable to a gear device such as a speed reducer. Background Art

[0003] There is known a gear device in which a crankshaft is rotatably supported by a through hole formed in a carrier.

[0004] A conventional gear device is disclosed in Patent Document 1. In the gear device disclosed in Patent Document 1, the limiting member is fixed to the gear frame by threading the external threaded portion of the limiting member to the internal threaded portion of the gear frame, and the axial movement of the crankshaft is limited by the limiting member fixed to the gear frame.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-130536 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] As shown in Patent Document 1, in a conventional gear transmission, a restriction member that restricts axial movement of a crankshaft is fixed to the carrier by threading a male thread portion of the restriction member into a female thread portion of the carrier.

[0008] However, when the limiting member is fastened to the gear rack, the roundness or cylindricity of the rolling surface (also called the crank hole) of the rolling member decreases under the action of the fastening torque. If the rolling member rolls on the rolling surface with reduced roundness or cylindricity, the rolling surface may also be damaged.

[0009] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to improve the durability of a bearing holding mechanism by reducing the influence of tightening of a restricting member.

[0010] Solutions for solving problems

[0011] A bearing retaining mechanism according to one embodiment of the present invention includes: a first member having an inner circumferential surface including an internal threaded portion; a second member inserted into the inner circumferential surface; a rolling member rolling on a rolling surface formed on the second member; a crankshaft rotatably supported on the second member by means of the rolling member; and a limiting member having an external threaded portion threadedly fixed to the internal threaded portion of the first member and supported by the first member and the second member.

[0012] A bearing retaining mechanism according to one embodiment of the present invention includes: a first member having an inner circumferential surface including an internal threaded portion; a second member inserted into the inner circumferential surface; a rolling member rolling on a rolling surface formed on the second member; a crankshaft rotatably supported on the second member by means of the rolling member; and a limiting member having an external threaded portion threadedly fixed to the internal threaded portion and supported by the first member.

[0013] In one embodiment of the present invention, the second member is arranged with a gap therebetween.

[0014] In one embodiment of the present invention, the second member is a bushing.

[0015] Effects of the Invention

[0016] According to the bearing holding mechanism of one embodiment of the present invention, the durability of the bearing holding mechanism can be improved by reducing the influence of the tightening of the restriction member. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a cross-sectional view for explaining a gear device including a bearing holding mechanism according to an embodiment of the present invention.

[0018] Figure 2 It is a cross-sectional view for explaining a gear device including a bearing holding mechanism according to an embodiment of the present invention.

[0019] Figure 3 It is a magnified representation Figure 2 A diagram of a portion of a bearing retaining mechanism.

[0020] Description of Reference Numerals

[0021] 1. Gear device; 2. Outer cylinder; 3. Gear frame; 4. Swing gear; 5. Crankshaft; 6. Crankshaft bearing; 6A, 6B, rolling member; 7. Transmission gear; 9. Limiting member; 10, 110, bearing holding mechanism; 11A, 11B, bushing; 31, first gear frame body; 32, second gear frame body; 31b, 32d, crankshaft mounting portion (through hole); 31c, 32c, inner circumferential surface; 31d, 32g, internal thread portion; 31e, 32h, step portion (positioning portion); 61, rolling element; 62, retainer; 62b, second portion; 91a, 92a, external thread portion; 91b, insertion hole; 91C, limiting surface. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. For convenience of description, only main components of the components of the gear device are briefly shown in each drawing. The gear device shown in each drawing can include various components that are not shown.

[0023] Figure 1 An example of a bearing retaining mechanism 10 and a gear device 1 using the bearing retaining mechanism 10 according to an embodiment of the present invention is shown. As shown in the figure, the gear device 1 is, for example, an eccentric swing type gear device. The gear device 1 includes: an outer cylinder 2, a gear frame 3, a swing gear 4, a crankshaft 5 and a crankshaft bearing 6. The illustrated gear device 1 is configured to cause the outer cylinder 2 and the gear frame 3 to rotate relative to each other by causing the swing gear 4 to swing and rotate along with the rotation of the crankshaft 5. The gear frame 3 has a first gear frame body 31 and a second gear frame body 32. The gear frame 3 (i.e., the first gear frame body 31 and the second gear frame body 32) is an example of the "first component" in the claims.

[0024] The bearing retaining mechanism 10 includes: at least one of the first gear frame body 31 and the second gear frame body 32, the crankshaft 5, at least one of the rolling member 6A and the rolling member 6B, at least one of the bushing 11A and the bushing 11B, and the limiting member 9. The gear frame body 31 has an inner peripheral surface 31c, and the gear frame body 32 has an inner peripheral surface 32c. The inner peripheral surface 31c has an internal threaded portion 31d, and the inner peripheral surface 32c has an internal threaded portion 32g. The crankshaft 5 is rotatably supported on the inner periphery of the gear frame 3. The limiting member 9 has at least one of the first limiting member 91 and the second limiting member 92. The first limiting member 91 has an external threaded portion 91a, and the second limiting member 92 has an external threaded portion 92a. The external threaded portion 91a is threadedly coupled to the internal threaded portion 31d, and the external threaded portion 92a is threadedly coupled to the internal threaded portion 32g. The bushing 11A is provided between the first gear frame body 31 and the rolling member 6A, and the bushing 11B is provided between the second gear frame body 32 and the rolling member 6B. A rolling surface for the rolling member 6A is formed on the inner periphery of the bushing 11A, and a rolling surface for the rolling member 6B is formed on the inner periphery of the bushing 11B. The limiting member 9 threadedly coupled to the gear frame 3 is supported by the first gear frame body 31 and the bushing 11A, or by the second gear frame body 32 and the bushing 11B. The bushing 11A and the bushing 11B are examples of the "second member" in the claims. The second member may also be a member other than a bushing.

[0025] According to the bearing holding mechanism 10 of one embodiment of the present invention, since the pressure acting on the bushing 11A or the bushing 11B is dispersed to the first gear frame body 31 or the second gear frame body 32 when the limiting member 9 is tightened, the pressure acting on the bushing 11A or the bushing 11B can be reduced. As a result, the deformation of the rolling surface of the bushing 11A or the rolling surface of the bushing 11B can be suppressed. As a result, the durability of the bearing holding mechanism 10 can be improved.

[0026] Next, refer to Figure 2 and Figure 3 A bearing holding mechanism 110 according to another embodiment of the present invention is described. As shown in the figure, the bearing holding mechanism 110 includes: a first gear frame body 31 or a second gear frame body 32, a crankshaft 5, a rolling member 6A or a rolling member 6B, a bushing 111A or a bushing 111B, and a limiting member 9. In the bearing holding mechanism 110, the same structure as the bearing holding mechanism 10 is omitted. The bushing 111A is provided between the first gear frame body 31 and the rolling member 6A, and the bushing 111B is provided between the second gear frame body 32 and the rolling member 6B. A rolling surface for the rolling member 6A is formed on the inner periphery of the bushing 111A, and a rolling surface for the rolling member 6B is formed on the inner periphery of the bushing 111B. The limiting member 9 threadedly coupled to the gear frame 3 is supported by the first gear frame body 31 or the second gear frame body 32. The bushing 111A and the bushing 111B are examples of the "second member" in the claims.

[0027] In the bearing holding mechanism 110, a gap is formed between at least one of the limiting member 9 and the bushing 111A and between the limiting member and the bushing 111B. That is, the bushing 111A can be arranged with a gap between the first limiting member 91. Furthermore, the bushing 111B can be arranged with a gap between the second limiting member 92.

[0028] According to the bearing holding mechanism 110, since the pressure when the limiting member is tightened is borne by the first gear frame body 31 or the second gear frame body 32, the deformation of the rolling surface of the bushing 111A or the rolling surface of the bushing 111B can be suppressed. In addition, since a gap is provided between the bushing 111A and the limiting member 9 or between the bushing 111B and the limiting member 9, the pressure from the limiting member 9 does not directly act on the bushing 111A or the bushing 111B, and thus the deformation of the rolling surface of the bushing 111A or the rolling surface of the bushing 111B can be suppressed. Thus, the durability of the bearing holding mechanism 110 can be improved.

[0029] Next, further explain Figure 1 and Figure 2The structure of the gear device 1 shown in the figure. In the gear device 1, the outer cylinder 2 is configured in a substantially cylindrical shape with the axis X1 as the central axis. A plurality of pin grooves are formed on the inner circumferential surface 2a of the outer cylinder 2. Each pin groove is arranged in a manner extending along the axis X1 direction and has a semicircular cross-sectional shape in a cross section orthogonal to the axis X1 direction. The pin grooves are arranged at equal intervals along the circumferential direction of the outer cylinder 2.

[0030] The gear device 1 further includes a plurality of internal tooth pins 8 mounted on the inner peripheral surface 2a of the outer cylinder 2. Each internal tooth pin 8 is cylindrical and extends in the direction of the axis X1. Each internal tooth pin 8 is mounted in a pin groove formed in the inner peripheral surface 2a of the outer cylinder 2.

[0031] A plurality of mounting holes 2b are formed in the outer tube 2, which penetrate the outer tube 2 along the axis X1 direction. The mounting holes 2b are arranged at equal intervals along the circumferential direction of the outer tube 2. The mounting holes 2b can be used when a member constituting a joint portion of a robot (not shown) is mounted on the outer tube 2. For example, when a base constituting a joint portion of a robot is mounted on the outer tube 2, the outer tube 2 is configured as a member on the fixed side of the gear device 1.

[0032] The gear frame 3 is configured to sandwich the swing gear 4 in the axis X1 direction and is arranged concentrically with the outer cylinder 2. The gear frame 3 has a first gear frame body 31 and a second gear frame body 32 that are opposite to each other in the axis X1 direction. The first gear frame body 31 and the second gear frame body 32 are fastened to each other by a fastening member T1.

[0033] The first gear frame 31 is roughly disk-shaped. A portion of the first gear frame 31 is located inside the outer cylinder 2, and the remaining portion is located outside the outer cylinder 2 in the direction of the axis X1. A central hole 31a and a crankshaft mounting portion 31b are formed in the first gear frame 31. The central hole 31a is formed in the central portion of the first gear frame 31 in a manner that passes through the first gear frame 31 along the direction of the axis X1.

[0034] The crankshaft mounting portion 31b is a portion for mounting the crankshaft 5. The crankshaft mounting portions 31b are arranged along the circumferential direction of the gear frame 3 on the outside of the central hole 31a. Each crankshaft mounting portion 31b is formed by a through hole that penetrates the first gear frame body 31 along the axis X1 direction, or a recessed hole that makes a part of the first gear frame body 31 recessed along the axis X1 direction. Each crankshaft mounting portion 31b is formed in a manner that penetrates the first gear frame body 31 along the axis X1 direction. Moreover, it is configured so that three crankshaft mounting portions 31b are formed on the first gear frame body 31.

[0035] The second gear frame 32 has a substantially disk-shaped base plate 32a and a shaft 32b extending from the base plate 32a toward the first gear frame 31. A portion of the base plate 32a is located inside the outer cylinder 2, and the remaining portion is located outside the outer cylinder 2 in the axis X1 direction.

[0036] The shaft portion 32b extends from the end surface of the substrate portion 32a on the side of the first gear frame body 31 in the axis X1 direction along the axis X1 direction. A plurality of shaft portions 32b are arranged along the circumferential direction of the gear frame 3. In the present embodiment, the second gear frame body 32 is configured to have three shaft portions 32b. A central hole 32k, a crankshaft mounting portion 32d, and a mounting hole 32j are formed in the second gear frame body 32.

[0037] The center hole 32 k is formed in the center portion of the second gear carrier body 32 so as to penetrate the base plate portion 32 a of the second gear carrier body 32 along the axis X1 direction.

[0038] The crankshaft mounting portion 32d is a portion for mounting the crankshaft 5. A plurality of crankshaft mounting portions 32d are formed on the outer side of the central hole 32k and arranged along the circumferential direction of the gear frame 3. Each crankshaft mounting portion 32d is formed by a through hole that penetrates the substrate portion 32a along the axis X1 direction, or a recessed hole that makes a part of the substrate portion 32a recessed along the axis X1 direction. In the present embodiment, each crankshaft mounting portion 32d is formed in a manner that penetrates the substrate portion 32a of the second gear frame body 32 along the axis X1 direction. Moreover, each crankshaft mounting portion 32d is arranged corresponding to the position of each crankshaft mounting portion 31b formed on the first gear frame body 31.

[0039] The mounting hole 32j is formed in such a manner that the end surface of the second gear frame body 32 on the side opposite to the first gear frame body 31 is recessed along the axis X1 direction. The mounting hole 32j is used to mount the object side member such as the rotating body constituting the joint part of the robot to the gear frame 3. In the case where the rotating body constituting the joint part of the robot is mounted on the gear frame 3, the gear frame 3 becomes a member on the rotating side of the gear device 1. In addition, in the case where, for example, the base constituting the joint part of the robot is mounted on the gear frame 3, the rotating body constituting the joint part of the robot is mounted on the outer cylinder 2, whereby the gear frame 3 becomes a member on the fixed side of the gear device 1 and the outer cylinder 2 becomes a member on the rotating side of the gear device 1.

[0040] The gear device 1 further includes main bearings B1 and B2. The main bearings B1 and B2 are disposed between the outer peripheral surface of the gear frame 3 and the inner peripheral surface 2a of the outer cylinder 2. Specifically, the main bearing B1 is disposed between the outer peripheral surface of the first gear frame body 31 and the inner peripheral surface 2a of the outer cylinder 2, and the main bearing B2 is disposed between the outer peripheral surface of the base plate portion 32a of the second gear frame body 32 and the inner peripheral surface 2a of the outer cylinder 2. The main bearings B1 and B2 allow relative rotation between the outer cylinder 2 and the gear frame 3.

[0041] At the crankshaft mounting portions 31b and 32d, the crankshaft 5 is supported on the gear frame 3 in a rotatable manner. The gear device 1 also includes a crankshaft bearing 6, which includes rolling members (crankshaft bearings) 6A and 6B that allow the crankshaft 5 to rotate relative to the gear frame 3. The crankshaft 5 is supported on the gear frame 3 by means of the crankshaft bearings 6A and 6B. In the present embodiment, three crankshafts 5 are arranged along the circumferential direction of the gear frame 3. In addition, the number of crankshafts 5 is arbitrary and can be appropriately changed according to the usage form of the gear device 1.

[0042] The crankshaft 5 includes a shaft body 51 extending in the direction of the axis X1 and eccentric portions 54 and 55 that are eccentric with respect to the shaft body 51 .

[0043] The shaft body 51 includes a first journal portion (large diameter portion) 51b, a second journal portion (large diameter portion) 51c, and a small diameter portion 51a having an outer diameter slightly smaller than the outer diameters of the first journal portion 51b and the second journal portion 51c.

[0044] The first journal portion 51b is located in the crankshaft mounting portion 31b of the first carrier body 31. A rolling member (first crankshaft bearing) 6A is mounted on the outer peripheral surface of the first journal portion 51b.

[0045] The second journal portion 51c has the same outer diameter as the first journal portion 51b. The second journal portion 51c is located in the crankshaft mounting portion 32d of the second carrier body 32. A rolling member (second crankshaft bearing) 6B is mounted on the outer peripheral surface of the second journal portion 51c.

[0046] The small diameter portion 51a is adjacent to the first journal portion 51b in the direction of the axis X1 and extends to the side opposite to the second journal portion 51c. A portion of the small diameter portion 51a is located outside the crankshaft mounting portion 31b. In addition, the small diameter portion 51a may be omitted, and the first journal portion 51b may extend from the inside of the crankshaft mounting portion 31b to the outside of the crankshaft mounting portion 31b.

[0047] The eccentric parts 54 and 55 are located between the first journal part 51b and the second journal part 51c in the axis X1 direction. The swing gear 4 is mounted on the eccentric parts 54 and 55 via eccentric bearings A1 and A2. The eccentric bearings A1 and A2 allow the eccentric parts 54 and 55 and the swing gear 4 to rotate relative to each other.

[0048] The swing gear 4 is located in the outer cylinder 2, and is sandwiched between the base plate portion 32a of the second gear frame 32 and the first gear frame 31 in the direction of the axis X1. The gear device 1 also includes eccentric bearings A1 and A2, and the swing gear 4 has a first swing gear 41 mounted on the first eccentric portion 54 by means of the eccentric bearing A1 and a second swing gear 42 mounted on the second eccentric portion 55 by means of the eccentric bearing A2. The swing gears 41 and 42 have an outer diameter slightly smaller than the inner diameter of the outer cylinder 2, and a plurality of external teeth are formed on their outer peripheral surfaces. The number of external teeth formed on the outer peripheral surfaces of the swing gears 41 and 42 is slightly less than the number of internal tooth pins 8. As a result, the first swing gear 41 and the second swing gear 42 can swing and rotate in different phases from each other in the inner cylinder 2 in a manner that each external tooth meshes with each internal tooth pin 8.

[0049] The first swing gear 41 is formed with a center hole 41 a corresponding to the center hole 31 a of the first gear frame 31 , an insertion hole 41 b into which the shaft portion 32 b is inserted, and a crankshaft mounting portion 41 c into which the first eccentric portion 54 is inserted.

[0050] The second swing gear 42 is formed with a center hole 42a corresponding to the position of the center hole 32k of the second gear frame 32, an insertion hole 42b into which the shaft portion 32b is inserted, and a crankshaft mounting portion 42c into which the second eccentric portion 55 is inserted.

[0051] In the present embodiment, for example, the swing gear 4 includes two swing gears, the first swing gear 41 and the second swing gear 42 , but the present invention is not limited thereto and the swing gear 4 may include only one swing gear or may include three or more swing gears.

[0052] The gear device 1 also includes a transmission gear 7, which transmits a driving force to the crankshaft 5 to rotate the crankshaft 5. The transmission gear 7 can be configured to be provided with three corresponding to the positions of the three crankshafts 5. The transmission gear 7 is located on the side opposite to the second gear frame body 32 across the first gear frame body 31 in the direction of the axis X1. The transmission gear 7 is mounted on the small diameter portion 51a of the shaft body 51 of the crankshaft 5. The movement of the transmission gear 7 in the direction of the axis X1 is limited by a retaining ring mounted on the small diameter portion 51a of the shaft body 51 in a manner that clamps the transmission gear 7 from both sides in the direction of the axis X1.

[0053] In addition, the transmission gear 7 is located on the opposite side of the first gear frame 31 and the second gear frame 32 in the axis X1 direction, but is not limited to this. The transmission gear 7 may also be located between the first eccentric portion 54 and the second eccentric portion 55. That is, the configuration of the transmission gear 7 is arbitrary and can be appropriately changed according to the form of the gear device 1.

[0054] The transmission gear 7 has a plurality of external teeth on its outer peripheral surface, and the input shaft of the motor (not shown) is meshed with the plurality of external teeth, thereby transmitting the driving force (torque) of the motor to the crankshaft 5. Then, the eccentric parts 54 and 55 of the crankshaft 5 receiving the driving force from the transmission gear 7 rotate, and the swing gear 4 swings and rotates in the outer cylinder 2 in accordance with the rotation. As a result, the outer cylinder 2 and the gear frame 3 rotate relative to each other.

[0055] The gear device 1 further includes a limiting member 9 for limiting the movement of the crankshaft 5 in the direction of the axis X1. The limiting member 9 includes a first limiting member 91 and a second limiting member 92 that are separated from each other in the direction of the axis X1. The first limiting member 91 and the second limiting member 92 sandwich the crankshaft 5 in the direction of the axis X1. Thus, the first limiting member 91 and the second limiting member 92 limit the movement of the crankshaft 5 in the direction of the axis X1. The bearing retaining mechanism 10 and the bearing retaining mechanism 110 are Figure 1 and Figure 2 The gear device 1 is formed on both sides of the gear frame 3 in the axis X1 direction. Figure 3 2 shows the bearing holding mechanism 110 located on the upper side in the axis X1 direction of the gear device 1 .

[0056] The first limiting member 91 is in the shape of a disk, and an insertion hole 91b is formed in the first limiting member 91, which passes through the central portion along the axis X1 direction. The diameter of the insertion hole 91b is set to be slightly larger than the diameter of the small diameter portion 51a and smaller than the diameter of the first shaft neck portion 51b. Figure 2 As shown in FIG. 1 , the first restricting member 91 is arranged so that the small diameter portion 51 a is located in the insertion hole 91 b .

[0057] The first restriction member 91 has an external thread portion 91a for fixing the first restriction member 91 to the carrier 3. The external thread portion 91a is formed on the entire periphery of the outer peripheral portion of the first restriction member 91.

[0058] The inner circumferential surface 31c of the first gear frame body 31 forming the crankshaft mounting portion 31b has: an internal thread portion 31d, a step portion 31e, and a support portion 31f. In the present embodiment, the internal thread portion 31d, the step portion 31e, and the support portion 31f are continuous from the outer end surface 31A side of the first gear frame body 31 in the order of the internal thread portion 31d, the step portion 31e, and the support portion 31f.

[0059] The internal thread portion 31d is formed from the end of the inner peripheral surface 31c on the outer end surface 31A side to the middle part of the inner peripheral surface 31c in the axis X1 direction. The external thread portion 91a is threadedly engaged with the internal thread portion 31d. Thus, the restricting member 9 is configured to be attached to the gear frame 3.

[0060] The step portion 31e connects the internal thread portion 31d and the support portion 31f. The step portion 31e extends from the end of the internal thread portion 31d on the first swing gear 41 side in the axis X1 direction to the radial inner side of the crankshaft 5. In the direction orthogonal to the axis X1 direction, the step portion 31e is arranged in line with the axial end face 51A, which is the end face of the first journal portion 51b on the side opposite to the eccentric portion 54.

[0061] The outer peripheral portion (restriction surface 91B) of the main surface 91A of the first restriction member 91 contacts the step portion 31e in the axis X1 direction. The central portion (restriction surface 91C) of the main surface 91A of the first restriction member 91 contacts the axial end surface 51A of the first journal portion 51b.

[0062] In addition, in the present embodiment, the limiting surface 91C contacts the axial end surface 51A of the first journal portion 51b, but the present invention is not limited thereto. The limiting surface 91C may also be arranged with a gap between the axial end surface 51A and the limiting surface 91C in the axis X1 direction. In this case, the step portion 31e is located closer to the outer end surface 31A side than the axial end surface 51A in the axis X1 direction.

[0063] The support portion 31f extends from the inner end of the step portion 31e in the radial direction of the crankshaft 5 along the axis X1 direction toward the first swing gear 41. The support portion 31f is configured to support the first journal portion 51b rotatably by means of a rolling member (first crankshaft bearing) 6A, and the rolling member (first crankshaft bearing) 6A has a rolling element 61 extending along the axis X1 direction. By making the rolling element 61 rotate freely between the support portion 31f and the first journal portion 51b, the crankshaft 5 can be relatively rotated with respect to the gear carrier 3.

[0064] The second limiting member 92 can be configured as a disc shape in the same manner as the first limiting member 91. The second limiting member 92 forms an insertion hole 92b in the central portion in the same manner as the first limiting member 91. Moreover, the second limiting member 92 has an external threaded portion 92a in the same manner as the first limiting member 91. Moreover, the inner circumferential surface 32c of the second gear frame body 32 forming the crankshaft mounting portion 32d has an internal threaded portion 32g, a step portion 32h and a support portion 32f in the same manner as the inner circumferential surface 31c of the first gear frame body 31. Moreover, the rolling member (second crankshaft bearing) 6B has a rolling element 61 in the same manner as the rolling member (first crankshaft bearing) 6A. The second limiting member 92 is provided in a manner symmetrical with respect to the first limiting member 91 in the direction of the axis X1, the inner circumferential surface 32c of the second gear carrier body 32 is provided in a manner symmetrical with respect to the inner circumferential surface 31c of the first gear carrier body 31 in the direction of the axis X1, and the rolling member (second crankshaft bearing) 6B is provided in a manner symmetrical with respect to the first crankshaft bearing 6A in the direction of the axis X1. Therefore, a detailed description of the respective shapes and configurations of the second limiting member 92, the inner circumferential surface 32c of the second gear carrier body 32, and the rolling member (second crankshaft bearing) 6B is omitted.

[0065] The second limiting member 92 contacts the step portion 32h in the direction of the axis X1, and at this position is opposite to the axial end face 51B of the second journal portion 51c which is the end face on the side close to the outer end face 32A. Thus, the second limiting member 92 limits the movement of the crankshaft 5 toward the outer end face 32A in the direction of the axis X1. Moreover, the second limiting member 92 is opposite to the second portion 62b of the retainer 62 of the second crankshaft bearing 6B in the direction of the axis X1. Thus, the second limiting member 92 limits the movement of the retainer 62 toward the outer end face 32A in the direction of the axis X1. Moreover, recesses 91e and 92e are formed in the first limiting member 91 and the second limiting member 92. By inserting a jig into the recesses 91e and 92e, the first limiting member 91 and the second limiting member 92 can be rotated at a specified tightening torque. As Figure 2 As shown, the hole may be a through hole, and the lubricity of the rolling members 6A and 6B may be improved by passing a lubricant through the through hole.

[0066] The above is a description of an exemplary embodiment of the present invention. The above embodiment is not limited to the above description, but can be applied to various gear devices. Some of the various features described in connection with one embodiment of the above various embodiments can also be applied to the gear device described in connection with another embodiment.

Claims

1. A bearing retaining mechanism, wherein: The bearing retaining mechanism comprises: A first member having an inner peripheral surface including an internal thread portion; a second member inserted into the inner peripheral surface; a rolling member that rolls on a rolling surface formed on the second member; a crankshaft rotatably supported by the second member via the rolling member; and The restricting member has a male thread portion threadedly fixed to the female thread portion of the first member and is supported by the first member and the second member.

2. A bearing retaining mechanism, wherein: The bearing retaining mechanism comprises: A first member having an inner peripheral surface including an internal thread portion; a second member inserted into the inner peripheral surface; a rolling member that rolls on a rolling surface formed on the second member; a crankshaft rotatably supported by the second member via the rolling member; and The restricting member includes a male thread portion threadedly fixed to the female thread portion and is supported by the first member.

3. The bearing holding mechanism according to claim 2, wherein: The second member is arranged with a gap therebetween.

4. The bearing holding mechanism according to any one of claims 1 to 3, wherein: The second member is a bushing.

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