Eccentric oscillation gear device and method for assembling eccentric oscillation gear device

Abstract

To provide an eccentric oscillation gear device capable of obtaining excellent workability in assembly work in a case of using a separable bearing for a crank bearing.SOLUTION: An eccentric oscillation gear device comprises a crankshaft 14 having an eccentric part 12, and a crank bearing 22A supporting the crankshaft 14 at a position axially deviating from the eccentric part 12. The crank bearing 22A is a separable bearing in which an inner ring 56 can be axially separated from a rolling element 50, and comprises a restriction member 60 capable of restricting axial movement of the rolling element 50 relative to the inner ring 56 when an outer ring 54 of the crank bearing 22A is separated from the rolling element 50.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an eccentric swing type gear device.

Background Art

[0002] Patent Document 1 discloses an eccentric swing type gear device including a crankshaft having an eccentric portion, a crankshaft bearing that supports the crankshaft at a position axially displaced with respect to the eccentric portion, and a carrier that supports the crankshaft bearing. This crankshaft bearing uses a separable bearing in which the inner ring is separable axially with respect to the rolling elements. The outer ring of the crankshaft bearing of Patent Document 1 is integrally provided by the same member as the carrier, and its inner ring is integrally provided by the same member as the crankshaft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the separable bearing is used as the crankshaft bearing, in the assembly process of the gear device, when the outer ring is separated from the rolling elements, axial movement of the rolling elements arranged on the inner ring is allowed. Therefore, there is a problem that the workability in the assembly work deteriorates because the rolling elements on the inner ring are largely displaced axially during the assembly process.

[0005] Therefore, one object of the present disclosure is to provide an eccentric swing type gear device capable of obtaining good workability in the assembly work when a separable bearing is used as the crankshaft bearing.

Means for Solving the Problems

[0006] The eccentric swing type gear device of the present disclosure includes a crankshaft having an eccentric portion and a crankshaft bearing that supports the crankshaft at a position axially displaced with respect to the eccentric portion. The crankshaft bearing is a separable bearing capable of axially separating the inner ring with respect to the rolling elements. When the outer ring of the crankshaft bearing is separated from the rolling elements, the eccentric swing type gear device includes a regulating member capable of regulating the axial movement of the rolling elements with respect to the inner ring.

Effect of the Invention

[0007] According to the present disclosure, when a separable bearing is used for the crankshaft bearing, good workability can be obtained in the assembly work.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments for implementing the eccentric swing type gear device (hereinafter, also simply referred to as a gear device) of the present disclosure will be described. The same or equivalent elements are denoted by the same reference numerals, and redundant descriptions will be omitted. In each drawing, for convenience of explanation, components are appropriately omitted, enlarged, or reduced. The drawings are to be viewed in accordance with the direction of the reference numerals.

[0010] Refer to Fig. 1. The gear device 10 is incorporated into a driven machine as part of the driven machine. The driven machine is, for example, various machines such as industrial machines (machine tools, construction machines, etc.), robots (industrial robots, service robots, etc.), transportation equipment (conveyors, vehicles, etc.).

[0011] The gear device 10 includes a crankshaft 14 having at least one eccentric portion 12, a swing gear 16 swung by the eccentric portion 12, a meshing gear 18 meshing with the swing gear 16, and a casing 20 disposed radially outside the swing gear 16. In addition, the gear device 10 includes crankshaft bearings 22A and 22B that support the crankshaft 14 at positions axially displaced with respect to the eccentric portion 12 of the crankshaft 14, and carriers 24A and 24B that support the crankshaft bearings 22A and 22B. Hereinafter, the direction along the swing center C16A of the swing gear 16 is referred to as the axial direction of the swing gear 16, and with respect to the radial direction and the circumferential direction centered on the swing center C16A, they are referred to as the radial direction and the circumferential direction of the swing gear 16.

[0012] In this embodiment, a distribution type eccentric swing type gear device 10 will be described. This type of gear device 10 includes a plurality of crankshafts 14 disposed at positions offset in the radial direction of the swing gear 16 from the swing center C16A of the swing gear 16, and a crankshaft gear 26 fixed to at least one crankshaft 14.

[0013] The gear device 10 includes an input member to which rotation is input from an external drive source, and an output member that outputs rotation to an external driven member. Here, an example will be described in which the crankshaft gear 26 is the input member and the second carrier 24B described later is the output member. The drive source is, for example, a motor, but in addition, a gear motor, an engine, etc. may also be used.

[0014] The number of crankshafts 14 in this embodiment is three, and only one of them is shown in the figure. The plurality of crankshafts 14 are arranged at intervals in the circumferential direction of the swing gear 16. The plurality of crankshafts 14 penetrate the carriers 24A and 24B together with the swing gear 16 in the axial direction of the swing gear 16.

[0015] The crankshaft 14 includes at least one (here, two) eccentric portions 12, and shaft portions 28A and 28B provided on both axial sides of the eccentric portion 12. The shaft portions 28A and 28B include an input-side shaft portion 28A (one-side shaft portion) provided on one axial side (the right side of the drawing in FIG. 1) of the eccentric portion 12, and an output-side shaft portion 28B (the other-side shaft portion) provided on the other axial side (the left side of the drawing in FIG. 1) of the eccentric portion 12. In this specification, for convenience of explanation, one axial side is referred to as the input side, and the other axial side is referred to as the output side. The eccentric portion 12 of the present embodiment is integrally provided by the same member as the shaft portions 28A and 28B, but may be provided separately from the shaft portions 28A and 28B.

[0016] The axis C12 of the eccentric portion 12 is eccentric with respect to the rotation center line C14 of the crankshaft 14. The eccentric portion 12 has a circular shape centered on the axis C12. The eccentric portion 12 can swing the oscillating gear 16 by rotating around the rotation center line C14 of the crankshaft 14. Here, "swing" means that the gear center C16B of the oscillating gear 16 rotates around the swing center C16A. The number of the eccentric portions 12 is not particularly limited, and may be either a single one or three or more.

[0017] The number of the crankshaft gears 26 in the present embodiment is three, and only one of them is shown in the figure. The number of the crankshaft gears 26 may be a single one. The plurality of crankshaft gears 26 are individually fixed to each of the plurality of crankshafts 14. A common transmission gear 30 meshes with the crankshaft gears 26 of each of the plurality of crankshafts 14. The rotation output from the drive source is distributed to each of the plurality of crankshafts 14 via the transmission gear 30. The transmission gear 30 is provided, for example, on the outer peripheral portion of the output shaft 32 of the drive source.

[0018] A central hole 26a through which an input-side shaft portion 28A of the crankshaft 14 penetrates is formed in the central portion of the crankshaft gear 26. The axial position of the crankshaft gear 26 with respect to the crankshaft 14 is fixed by a gear fixing member 34 such as a retaining ring attached to the crankshaft 14. The crankshaft gear 26 is integrally rotatably coupled to the crankshaft 14 by a coupling structure 36. Although the spline structure is exemplified as this coupling structure 36, other structures such as a key structure may also be used.

[0019] In the present embodiment, the oscillating gear 16 is an external gear, and the meshing gear 18 is an internal gear. The oscillating gears 16 are individually provided corresponding to each of the plurality of eccentric portions 12 and are supported by the corresponding eccentric portions 12 via eccentric bearings 38. The meshing gear 18 of the present embodiment includes a meshing gear body 18a integrated with the casing 20 and a plurality of tooth portions 18b provided on the meshing gear body 18a and meshing with the oscillating gear 16. The plurality of tooth portions 18b of the present embodiment are integrally provided by the same member as the meshing gear body 18a. Alternatively, the plurality of tooth portions 18b may be provided by a plurality of pins rotatably supported by the meshing gear body 18a.

[0020] The crankshaft bearings 22A and 22B include a first crankshaft bearing 22A that supports the input-side shaft portion 28A of the crankshaft 14 and a second crankshaft bearing 22B that supports the output-side shaft portion 28B of the crankshaft 14. An eccentric bearing restricting member 39 is disposed between each of the crankshaft bearings 22A and 22B and the eccentric bearing 38. The eccentric bearing restricting member 39 restricts the axial outward movement of the eccentric bearing 38 by contacting the eccentric bearing 38 from the axial outside. The eccentric bearing restricting member 39 is provided separately from the crankshaft 14.

[0021] The carriers 24A and 24B include a first carrier 24A that supports the first crank bearing 22A and a second carrier 24B that supports the second crank bearing 22B. A first shaft hole 24Aa into which the input-side shaft portion 28A of the crankshaft 14 is inserted is formed in the first carrier 24A. A second shaft hole 24Ba into which the output-side shaft portion 28B of the crankshaft 14 is inserted is formed in the second carrier 24B. The first carrier 24A and the second carrier 24B are connected via a pin body 40 that passes through the oscillating gear 16. The pin body 40 is integrated with one of the first carrier 24A and the second carrier 24B (here, the second carrier 24B) and is fixed by a fixing member 42 such as a bolt in a state of being in contact with the other thereof (here, the first carrier 24A).

[0022] A main bearing 44 is arranged between the casing 20 and the carriers 24A and 24B. The main bearing 44 exemplifies an angular ball bearing, but its specific example is not particularly limited and may be constituted by a cross roller bearing, a ball bearing, or the like.

[0023] An example of the operation of the above-described gear device 10 will be described. When the transmission gear 30 rotates due to the output of the drive source, the rotation of the transmission gear 30 is transmitted to at least one crankshaft 14 via the crankshaft gear 26. At this time, the rotation of the transmission gear 30 is decelerated by the crankshaft gear 26 and then transmitted to the crankshaft 14. When the crankshaft 14 rotates, the oscillating gear 16 oscillates due to the eccentric portion 12 of the crankshaft 14. When the oscillating gear 16 oscillates, the meshing position between the oscillating gear 16 and the meshing gear 18 changes in the circumferential direction. Accordingly, each time the crankshaft 14 makes one rotation, either one of the oscillating gear 16 and the meshing gear 18 (here, the oscillating gear 16) rotates, and the rotation component thereof is taken out by the output member (here, the second carrier 24B). At this time, with respect to the input rotation input to the crankshaft 14, an output rotation decelerated at a reduction ratio corresponding to the difference in the number of teeth between the oscillating gear 16 and the meshing gear 18 is taken out by the output member.

[0024] Refer to FIG. 2. Hereinafter, components related to one crankshaft 14 (such as crankshaft bearings, carriers, crankshaft gears 26, etc.) will be described with attention paid thereto. In explaining the positional relationships regarding these, mainly, the axial direction, radial direction, and circumferential direction of the crankshaft 14 will be used for the explanation. Also, in explaining these, there may be cases of the outer side in the axial direction and the inner side in the axial direction. The outer side in the axial direction here refers to the side that moves away from the eccentric portion 12 in the axial direction of the crankshaft 14, and the inner side in the axial direction refers to the side that approaches the eccentric portion 12 in the axial direction. Also, hereinafter, regarding the configuration common to the first and second crankshaft bearings 22A and 22B, the explanation will be made with reference to the first crankshaft bearing 22A.

[0025] The crankshaft bearings 22A and 22B include a plurality of rolling elements 50, a cage 52 that rotatably holds the plurality of rolling elements 50, an outer ring 54 and an inner ring 56 on which the plurality of rolling elements 50 roll.

[0026] The cage 52 is rotatable around the rotation center line C14 of the crankshaft 14 together with the plurality of rolling elements 50. The plurality of rolling elements 50 and the cage 52 constitute a rolling element unit 58.

[0027] The outer ring 54 is integrated with the carriers 24A and 24B. Here, "integration" means that the two mentioned components are integrated, regardless of whether they are the same member or separate entities. The outer ring 54 of the first crank bearing 22A is integrated with the first carrier 24A, and the outer ring 54 of the second crank bearing 22B is integrated with the second carrier 24B. In the present embodiment, the outer ring 54 is integrally provided by the same member as the carriers 24A and 24B, and is formed by the inner peripheral portions of their shaft holes 24Aa and 24Ba. In addition to this, the outer ring 54 may be provided separately from the carriers 24A and 24B and fixed to the shaft holes 24Aa and 24Ba of the carriers 24A and 24B by interference fit or the like. The outer ring 54 includes an outer raceway surface 54a on which the rolling elements 50 roll, and an outer movement restricting portion 54b that restricts the axial outward movement of the rolling elements 50. The outer raceway surface 54a has a shape in which the inner diameter gradually decreases as it goes axially outward. The outer movement restricting portion 54b of the present embodiment is provided axially outward with respect to the rolling elements 50 and forms a stepped shape that protrudes radially inward with respect to the outer raceway surface 54a.

[0028] The inner ring 56 is integrated with the crankshaft 14. In the present embodiment, the inner ring 56 is integrally provided by the same member as the crankshaft 14 and is formed by its outer peripheral portion. In addition to this, the inner ring 56 may be provided separately from the crankshaft 14 and fixed to the outer peripheral portion of the crankshaft 14 by interference fit or the like. The inner ring 56 includes an inner raceway surface 56a on which the rolling elements 50 roll, and an inner movement restricting portion 56b that restricts the axial inward movement of the rolling elements 50. The inner raceway surface 56a has a shape in which the outer diameter gradually decreases as it goes axially outward. The inner movement restricting portion 56b of the present embodiment is provided axially inward with respect to the rolling elements 50 and forms a stepped shape that protrudes radially outward with respect to the inner raceway surface 56a.

[0029] The crankshaft bearings 22A and 22B are separable bearings that can axially separate the outer ring 54 and the inner ring 56 with respect to the rolling elements 50. Both the first and second crankshaft bearings 22A and 22B are separable bearings. Here, an example using a tapered roller bearing as this separable bearing is shown, but the specific example is not particularly limited, and an angular ball bearing or the like may be used. When it is a tapered roller bearing, the rolling elements 50 are tapered rollers, and when it is an angular ball bearing, the rolling elements 50 are spherical bodies.

[0030] In constituting the separable bearing, the outer ring 54 is provided axially inward with respect to the rolling elements 50 and does not have an inner movement restricting portion (flange portion) that restricts the relative movement of the outer ring 54 axially outward with respect to the rolling elements 50. Thereby, by relatively moving the outer ring 54 axially outward with respect to the rolling elements 50, the outer ring 54 can be axially separated from the rolling elements 50. Further, in constituting the separable bearing, the inner ring 56 is provided axially outward with respect to the rolling elements 50 and does not have an outer movement restricting portion (flange portion) that restricts the relative movement of the rolling elements 50 axially outward with respect to the inner ring 56. Thereby, by relatively moving the rolling elements 50 axially outward with respect to the inner ring 56, the rolling elements 50 can be axially separated from the inner ring 56. The condition that each component of such a separable bearing is separated only needs to be satisfied at least during the assembly process of the gear device 10.

[0031] The gear device 10 includes a regulating member 60 that can regulate the axial movement of the rolling elements 50 with respect to the inner ring 56 of the first crankshaft bearing 22A. The regulating member 60 can regulate the axial movement by contacting the rolling elements 50 from the axially outer side. The condition of "regulating the axial movement" only needs to be satisfied when the outer ring 54 of the first crankshaft bearing 22A is separated from the rolling elements 50 during the assembly process of the gear device 10 as shown in FIG. 4. In this state, the axial movement of the rolling elements 50 axially outward with respect to the inner ring 56 is allowed, and the displacement of the rolling elements 50 with respect to the inner ring 56 occurs. The condition of "regulating the axial movement" does not necessarily need to be satisfied when the gear device 10 is in an operating state after the assembly of the gear device 10 is completed.

[0032] The regulating member 60 is provided separately from the inner ring 56. The regulating member 60 of the present embodiment is attached to the crankshaft 14 on the same side (here, the input side) as the crankshaft gear 26 in the axial direction with respect to the eccentric portion 12 of the crankshaft 14. The regulating member 60 has a shape surrounding the crankshaft 14. As a shape satisfying this condition, the regulating member 60 of the present embodiment forms an annular shape continuous over the entire circumference around the rotation center line C14 of the crankshaft 14. In addition to this, the regulating member 60 may form a notched annular shape with a notch in a part of its circumferential direction.

[0033] The regulating member 60 includes a hard component 62 attached to the crankshaft 14 and a soft component 64 softer than the hard component 62. The material of the hard component 62 is preferably a metal-based material, but may be constituted by a resin-based material or the like. When the gears of the gear device 10 mesh with each other and generate heat during the operation of the gear device 10, the regulating member 60 can become high temperature due to heat conduction. Here, the gear pair refers to, for example, a pair of the crankshaft gear 26 and the transmission gear 30, as well as a pair of the swing gear 16 and the meshing gear 18. When a metal-based material is adopted as the material of the hard component 62, creep of the hard component 62 in a high temperature environment can be suppressed compared with the case of adopting a resin-based material, and rattling of the hard component 62 caused thereby can be suppressed.

[0034] Here, the metal-based material refers to a material mainly composed of metal (including alloys), and includes not only the case constituted only by metal but also the case constituted by a composite material of metal and other materials (for example, fiber-reinforced metal, etc.). The metal used here refers to, for example, iron-based materials such as cast iron and steel, and aluminum-based materials such as aluminum alloys. Here, the resin-based material refers to a material mainly composed of resin, and includes not only the case constituted only by resin but also the case constituted by a composite material of resin and other materials (for example, fiber-reinforced resin, etc.). The resin used here is, for example, a plastic-based material such as general-purpose engineering plastics and special engineering plastics.

[0035] The soft component 64 is composed of a rubber material, a sponge material, a gel material, etc., which are softer than the hard component 62. The soft component 64 is provided at a position axially opposed to the crank bearings 22A and 22B in the hard component 62. The soft component 64 of the present embodiment is provided at the first radially extending portion 68A (described later) of the hard component 62 as a position satisfying such conditions. When the soft component 64 is composed of an elastic material such as a rubber material, it may be integrated with the hard component 62 by adhesion (such as vulcanization adhesion), for example.

[0036] The hard component 62 includes an axially extending portion 66 extending in the axial direction and radially extending portions 68A and 68B extending in the radial direction. The radially extending portions 68A and 68B include a first radially extending portion 68A extending radially outward from the inner end portion of the axially extending portion 66 and a second radially extending portion 68B extending radially inward from the outer end portion of the axially extending portion 66.

[0037] The axially extending portion 66 of the regulating member 60 (hard component 62) is fixed to the outer peripheral portion of the crankshaft 14 by interference fit. Thereby, the regulating member 60 is detachably attached to the crankshaft 14. By fixing the regulating member 60 by interference fit, the regulating member 60 can be fixed without forming a groove portion on the outer peripheral portion of the crankshaft 14. Further, although not described later, since the regulating member 60 can be fixed to the crankshaft 14 without the crankshaft gear 26 that regulates the axial outward movement of the regulating member 60, there is also an advantage that the assembly freedom is improved.

[0038] The soft component 64 constitutes a contact portion 70 against which the cage 52 or the rolling elements 50 of the first crank bearing 22A can abut. The regulating member 60 can regulate the axial movement of the rolling elements 50 when the cage 52 or the rolling elements 50 abut against the contact portion 70. Here, an example is shown in which the object directly abutted by the contact portion 70 of the regulating member 60 is the cage 52. When the cage 52 abuts against the contact portion 70, the outward axial movement of the cage 52 is regulated, and when the rolling elements 50 abut against the cage 52, the outward axial movement of the rolling elements 50 is regulated. By forming the contact portion 70 with the soft component 64, wear associated with sliding with the regulating member 60 can be suppressed as compared with the case where the cage 52 or the rolling elements 50 abut against the hard component 62.

[0039] The second radially extending portion 68B of the hard component 62 constitutes a positioning portion 72 that is axially positioned with respect to the crankshaft 14. The positioning portion 72 is positioned with respect to the crankshaft 14 by abutting against a part of the crankshaft 14 from the outside in the axial direction. The "part of the crankshaft 14" here is a stepped portion 74 provided so as to protrude radially outward on the outer peripheral portion of the crankshaft 14, but it may also be the end face portion thereof. In the present embodiment, this stepped portion 74 is provided so as to protrude radially outward from the axially inner end portion of the male spline portion constituted by the coupling structure 36. The regulating member 60 of the present embodiment is regulated in its outward axial movement by the crankshaft gear 26 disposed axially outside the regulating member 60. By this positioning portion 72, the axial movement of the regulating member 60 toward the crank bearings 22A and 22B can be regulated, and an axial gap 76 can be stably formed between the contact portion 70 of the regulating member 60 and the crank bearings 22A and 22B.

[0040] This axial clearance 76 is provided to avoid wear due to sliding between the components (rolling elements 50, cage 52) of the first crank bearing 22A that rotates relative to the crankshaft 14 and the regulating member 60. The axial clearance 76 is provided over the entire circumference around the rotation center line C14 of the crankshaft 14 between the first crank bearing 22A and the regulating member 60. The axial dimension L76 of the axial clearance 76 has a size of 0 or more and is positively larger than the axial internal clearance of the first crank bearing 22A. Here, the axial internal clearance refers to the amount of play in the axial direction of the rolling elements 50 with respect to the outer ring 54 and the inner ring 56 of the first crank bearing 22A. Here, an example where this axial internal clearance becomes zero is shown. The axial dimension L76 of this axial clearance 76 refers to the axial dimension at the location where the axial dimension is the smallest between the first crank bearing 22A and the regulating member 60.

[0041] The axial clearance 76 of the present embodiment is provided between the first crank bearing 22A and the regulating member 60 when the rolling element 50 is in contact with the inner movement restricting portion 56b in the inner ring 56 of the first crank bearing 22A. In this state, in the present embodiment, a clearance 78 is provided between the outer movement restricting portion 54b in the outer ring 54 of the first crank bearing 22A and the rolling element 50. The axial dimension L76 of the axial clearance 76 is larger than the minimum axial dimension L78 of this clearance 78.

[0042] With such an axial clearance 76, the regulating member 60 satisfies the positional condition of being provided at a position where it does not contact the cage 52. This positional condition is satisfied when the gear device 10 is in an assembled state. This positional condition only needs to be satisfied when the regulating member 60 is arranged downward with respect to the cage 52. Consider the case where axial displacement of the cage 52 with respect to the rolling elements 50 is allowed. In this case, in order to satisfy the above-mentioned positional condition, the regulating member 60 only needs to be provided at a position where it does not contact the cage 52 when the cage 52 is located most axially outward within the range where the cage 52 can relatively move with respect to the rolling elements 50. Also, in order to satisfy this positional condition, the regulating member 60 only needs to be provided at a position where it does not contact the cage 52 that moves with the rolling elements 50 when the rolling elements 50 are located most axially outward within the range where the rolling elements 50 can relatively move with respect to the crankshaft 14 and the first carrier 24A. This "when the rolling elements 50 are located most axially outward within the range where the rolling elements 50 can relatively move" means that when the rolling elements 50 are tapered rollers, it can be a position where the movement axially outward is restricted by the tapered outer raceway surface 54a, or a position where the movement is restricted by the outer movement restricting portion 54b. In addition to this, this "when the rolling elements 50 are located most axially outward within the range where the rolling elements 50 can relatively move" means that when the rolling elements 50 are cylindrical rollers, it can be a position where the movement of the rolling elements 50 axially outward is restricted by the contact with a straight surface 77 extending along the axial direction that is continuous axially outward with respect to the inner raceway surface 56a. Thus, the outer movement restricting portion 54b of the outer ring 54 is not essential.

[0043] The effects of the above-described gear device 10 will be described. When a separable bearing is used for the first crank bearing 22A, during the assembly process of the gear device 10, when the rolling elements 50 and the outer ring 54 are separated, the axial movement of the rolling elements 50 (rolling element unit 58) on the inner ring 56 is permitted. Due to this, if the rolling elements 50 on the inner ring 56 are greatly displaced axially, it will take time to return them to their original positions. Also, depending on the amount of displacement of the rolling element unit 58 including the rolling elements 50, there is a risk that the rolling element unit 58 will come off the crankshaft 14. These factors combined result in a problem that the workability in the assembly work deteriorates due to the large displacement of the rolling elements 50 on the inner ring 56.

[0044] In this regard, the gear device 10 of the present embodiment includes a restricting member 60 capable of restricting the axial movement of the rolling elements 50 with respect to the inner ring 56 of the first crank bearing 22A. Therefore, even when the outer ring 54 is separated from the rolling elements 50 during the assembly process of the gear device 10, the large axial displacement of the rolling elements 50 on the inner ring 56 can be suppressed by the restricting member 60. As a result, even when a separable bearing is used for the first crank bearing 22A, by suppressing the occurrence of the problems caused by the displacement of the rolling elements 50 described above, good workability can be obtained in the assembly work of the gear device 10.

[0045] Also, if the outer ring 54 is placed over the rolling elements 50 while the rolling elements 50 are greatly displaced from the planned placement positions on the inner ring 56 of the first crank bearing 22A, there is a risk of damage to the raceway surfaces 54a, 56a of the outer ring 54 and the inner ring 56. In this regard, according to the present embodiment, since the large displacement of the rolling elements 50 can be suppressed by the restricting member 60, it is possible to avoid a situation where the raceway surfaces 54a, 56a of the outer ring 54 and the inner ring 56 are damaged due to the displacement.

[0046] The inner ring 56 of the crank bearing 22A is integrally provided by the same member as the crankshaft 14. Thereby, the number of parts around the crank bearing 22A can be reduced, and the product cost can be reduced. Further, when the inner ring 56 is integrally provided by the same member as the crankshaft 14, if an outer movement restricting portion for restricting the axial outward movement of the rolling elements 50 with respect to the inner ring 56 is directly formed on the crankshaft 14, the machining difficulty increases. In this regard, according to the present embodiment, even without directly forming the outer movement restricting portion on the crankshaft 14, by attaching the restricting member 60 to the crankshaft 14, the axial movement of the rolling elements 50 with respect to the inner ring 56 can be restricted. Therefore, the axial movement of the rolling elements 50 with respect to the inner ring 56 can be restricted without increasing the machining difficulty of the crankshaft 14.

[0047] Next, an assembling method of the gear device 10 will be described. The assembling method of the gear device 10 mainly includes a restricting member assembling step S10 (see FIG. 3) of assembling the restricting member 60 to the crankshaft 14, and a first assembling step S12 (see FIGS. 3 and 4) of assembling an output side bearing structure 80 (second bearing structure) including the crankshaft 14, the second crank bearing 22B, and the second carrier 24B. In addition to this, this assembling method includes a second assembling step S14 (see FIGS. 4 and 5) of assembling an input side bearing structure 82 (first bearing structure) including the crankshaft 14, the first crank bearing 22A, and the first carrier 24A, and a gear assembling step S16 (see FIG. 5) of assembling the crankshaft gear 26 to the crankshaft 14.

[0048] Refer to FIG. 3. Hereinafter, in order to distinguish the common components (rolling elements 50, cage 52, outer ring 54, inner ring 56) of the first crank bearing 22A and the second crank bearing 22B respectively, the components of the first crank bearing 22A are labeled with "first", and the components of the second crank bearing 22B are labeled with "second". In the regulating member assembling step S10, in advance, by arranging the rolling element unit 58 on the inner raceway surface 56a of the first inner ring 56 of the first crank bearing 22A integrated with the crankshaft 14, the first rolling element 50 is assembled to the crankshaft 14. At this time, the rolling element unit 58 is arranged on the first inner ring 56 by relatively moving the rolling element unit 58 axially inward with respect to the crankshaft 14. In the regulating member assembling step S10, with the rolling element 50 (rolling element unit 58) assembled to the crankshaft 14, a regulating member 60 that regulates the axial movement of the first rolling element 50 is fixed to the crankshaft 14, thereby assembling it to the crankshaft 14. In the present embodiment, before and after the regulating member assembling step S10, in addition to the crankshaft 14, a sub-assembly 84 combining the oscillating gear 16, the meshing gear 18, the casing 20, and the eccentric bearing 38 is assembled. When handling the crankshaft 14 in the subsequent steps, the sub-assembly 84 in which the crankshaft 14 is incorporated is handled.

[0049] Refer to FIGS. 3 and 4. The first assembling step S12 is a step of assembling the output-side bearing structure 80 such that the crankshaft 14 is supported by the second carrier 24B via the second crank bearing 22B. By going through the first assembling step S12, a sub-assembly 84 in which the output-side bearing structure 80 is incorporated can be obtained.

[0050] The first assembly step S12 of this embodiment is performed with the second carrier 24B having its input side facing upward placed on the workbench 86. At this time, the rolling element unit 58 is arranged on the outer raceway surface 54a of the second outer ring 54 of the second crank bearing 22B integrated with the second carrier 24B, so that the second rolling element 50 is pre-assembled to the second carrier 24B. In this state, by moving the crankshaft 14 (sub-assembly 84) integrated with the second inner ring 56 of the second crank bearing 22B downward in the vertical direction, the output side shaft portion 28B of the crankshaft 14 is inserted into the second shaft hole 24Ba of the second carrier 24B. Thereby, with the first rolling element 50 and the regulating member 60 assembled to the crankshaft 14, the crankshaft 14 integrated with the second inner ring 56 is assembled to the second rolling element 50 assembled to the second carrier 24B. Thereby, the output side bearing structure 80 is assembled, and the first assembly step S12 is completed.

[0051] When the second outer ring 54 of the second crank bearing 22B is separate from the second carrier 24B, the output side shaft portion 28B of the crankshaft 14 may be first inserted into the second shaft hole 24Ba of the second carrier 24B that is not integrated with the second outer ring 54. In this case, thereafter, the second outer ring 54 may be integrated with the second carrier 24B by fitting the second outer ring 54 into the second shaft hole 24Ba from the output side. Thereby, the output side bearing structure 80 is assembled, and the first assembly step S12 is completed. In the process of performing the above first assembly step S12, the state where the rolling element 50 and the regulating member 60 are assembled to the crankshaft 14 is maintained.

[0052] Refer to FIGS. 4 and 5. The second assembly step S14 is a step of assembling the input side bearing structure 82 so that the first carrier 24A is supported by the crankshaft 14 via the first crank bearing 22A. By going through the second assembly step S14, a sub-assembly 84 with the input side bearing structure 82 incorporated can be obtained.

[0053] The second assembly step S14 of this embodiment is performed with the second carrier 24B having its input side facing upward placed on the workbench 86. At this time, as described above, the first rolling element 50 of the first crank bearing 22A is pre-assembled to the crankshaft 14. In this state, in this embodiment, the first carrier 24A integrated with the first outer ring 54 of the first crank bearing 22A is moved downward in the vertical direction, so that the input side shaft portion 28A of the crankshaft 14 is inserted into the first shaft hole 24Aa of the first carrier 24A. In this embodiment, the crankshaft 14 is inserted into the first shaft hole 24Aa of the first carrier 24A until the pin body 40 integrated with the second carrier 24B abuts against the first carrier 24A. After that, the first carrier 24A and the second carrier 24B are connected using the pin body 40 by the fixing member 42 (see FIG. 1). As a result, with the restricting member 60 assembled to the crankshaft 14, the first outer ring 54 of the first crank bearing 22A is assembled to the first rolling element 50 assembled to the crankshaft 14. Here, the first outer ring 54 integrated with the first carrier 24A is assembled to the first rolling element 50 assembled to the crankshaft 14. Thereby, the input side bearing structure 82 is assembled, and the second assembly step S14 is completed.

[0054] When the first outer ring 54 of the first crank bearing 22A is separate from the first carrier 24A, the first outer ring 54 may be assembled to the first rolling element 50 assembled to the crankshaft 14 first, and then the first carrier 24A may be integrated with the first outer ring 54. At this time, the first carrier 24A may be integrated with the first outer ring 54 by inserting the first outer ring 54 into the first shaft hole 24Aa of the first carrier 24A. In addition to this, the input side shaft portion 28A of the crankshaft 14 may be inserted into the first shaft hole 24Aa of the first carrier 24A that is not integrated with the first outer ring 54 first. In this case, thereafter, the first outer ring 54 may be integrated with the first carrier 24A by fitting the first outer ring 54 into the first shaft hole 24Aa of the first carrier 24A from the input side. Thereby, the input side bearing structure 82 is assembled, and the second assembly step S14 is completed. In the process of performing the second assembly step S14 as described above, the rolling element 50 and the restricting member 60 are maintained in a state of being assembled to the crankshaft 14.

[0055] Refer to FIG. 5. The gear assembly step S16 of the present embodiment is performed with the second carrier 24B having its input side facing upward placed on the workbench 86. In the gear assembly step S16, the input side shaft portion 28A of the crankshaft 14 is inserted into the central hole 26a of the crankshaft gear 26. After that, by attaching the gear fixing member 34 to the crankshaft gear 26, the crankshaft gear 26 is fixed to the crankshaft 14. Thereby, the gear assembly step S16 is completed.

[0056] The effects of the above assembly method will be described. In the process of the second assembly step S14, the first outer ring 54 is separated from the first rolling elements 50 of the first crankshaft bearing 22A. In this case, the first rolling elements 50 (rolling element unit 58) can be greatly displaced axially outward from the crankshaft 14. For example, it is the case where a part of the operator accidentally hits the first rolling elements 50 (rolling element unit 58). In the second assembly step S14 of the present embodiment, since the crankshaft 14 with the restricting member 60 assembled in addition to the first rolling elements 50 is used, in the second assembly step S14, the large displacement of the rolling elements 50 can be suppressed by the restricting member 60.

[0057] As shown in FIG. 3, when the output side shaft portion 28B of the crankshaft 14 is inserted into the second shaft hole 24Ba of the second carrier 24B placed on the workbench 86, the second rolling elements 50 of the second crankshaft bearing 22B are assembled to the second carrier 24B. The axial position of the rolling elements 50 is restricted by the outer movement restricting portion 54b of the second outer ring 54 of the second crankshaft bearing 22B integrated with the second carrier 24B stationary on the workbench 86. Therefore, even if a separable bearing is used as the second crankshaft bearing 22B, in the process of performing the first assembly step S12, the problem of displacement of the second rolling elements 50 hardly occurs, and the restricting member 60 for suppressing the displacement becomes unnecessary.

[0058] On the other hand, the first rolling element 50 of the first crankshaft bearing 22A assembled to the input side shaft portion 28A of the crankshaft 14 is likely to be displaced relative to the crankshaft 14 in the process of moving the crankshaft 14 in the first assembly step S12. In this regard, in the present embodiment, in this first assembly step S12, the crankshaft 14 with the restricting member 60 assembled in addition to the first rolling element 50 of the first crankshaft bearing 22A is used. Therefore, in the first assembly step S12 where displacement of the first rolling element 50 of the first crankshaft bearing 22A is likely to be a problem, it is advantageous in that a large displacement thereof can be suppressed by the restricting member 60.

[0059] If the second assembly step S14 → the first assembly step S12 → the gear assembly step S16 are performed in this order, in the second assembly step S14, when moving the crankshaft 14 with the second rolling element 50 assembled thereto separated from the second outer ring 54 of the second crankshaft bearing 22B, a problem of displacement of the second rolling element 50 relative to the crankshaft 14 is likely to occur. In this case, in the second assembly step S14 and the first assembly step S12, the work is performed with the first carrier 24A having the output side facing upward placed on the workbench 86. After that, in the gear assembly step S16, it is necessary to turn the sub-assembly 84 in the vertical direction in order to place the second carrier 24B having the input side facing upward on the workbench 86. Here, considering the case where a restricting member 60 for restricting displacement of the second rolling element 50 is assembled to the crankshaft 14 as a countermeasure against displacement of the second rolling element 50 of the second crankshaft bearing 22B relative to the crankshaft 14 in the second assembly step S14. In this case, although a large displacement thereof can be suppressed by the restricting member 60 in the second assembly step S14 where displacement of the rolling element 50 relative to the crankshaft 14 is likely to be a problem, it becomes necessary to turn the sub-assembly 84 in the vertical direction.

[0060] On the other hand, consider the case where, as in the present embodiment, the first assembly step S12 → the second assembly step S14 → the gear assembly step S18 are performed in sequence. In this case, in the first assembly step S12, when moving the crankshaft 14 with the first rolling elements 50 assembled thereto separated from the first outer ring 54 of the first crankshaft bearing 22A, a problem of displacement of the first rolling elements 50 is likely to occur. In this case, as described above, in the process of performing the first assembly step S12 → the second assembly step S14 → the gear assembly step S16, the orientation of the sub-assembly 84 can be maintained, and there is no need to turn the sub-assembly 84 in the vertical direction. Therefore, in the first assembly step S12 where displacement of the first rolling elements 50 with respect to the crankshaft 14 is likely to be a problem, while suppressing such large displacement by the regulating member 60, there is no need to turn the sub-assembly 84 in the vertical direction, and particularly good workability can be obtained in the assembly work.

[0061] The above effects are obtained by satisfying the following first and second conditions. The first condition is that when the crankshaft gear 26 is fixed to the input-side shaft portion 28A of the crankshaft 14, the regulating member 60 is attached to the input-side shaft portion 28A of the crankshaft 14 that is on the same axial side as the crankshaft gear 26 with respect to the eccentric portion 12 of the crankshaft 14. The second condition is that in the process of assembling the gear device 10, when performing the first assembly step S12 → the second assembly step S14 in sequence, in the first assembly step S12, the first rolling elements 50 of the first crankshaft bearing 22A and the regulating member 60 are pre-assembled to the input-side shaft portion 28A of the crankshaft 14. The above effects are considered to be obtained when the second condition regarding the assembly method of the gear device 10 is satisfied if the first condition regarding the configuration of the gear device 10 is satisfied.

[0062] Other features of the gear device 10 will be described. Referring to FIG. 1, an input-side member 90 disposed on the input side with respect to the gear device 10 is attached to the gear device 10. The input-side member 90 is, for example, an adapter that connects the gear device 10 and a drive source. At least a part of an enclosed space 92 in which a lubricant is enclosed is provided inside the gear device 10. The enclosed space 92 of the present embodiment is formed by being surrounded by the gear device 10 and the input-side member 90.

[0063] Refer to FIG. 2. An outer passage 94 is formed axially outside the first crank bearing 22A between the first axial hole 24Aa of the first carrier 24A and the crankshaft 14. The lubricant attempting to flow axially inward into this outer passage 94 may contain contaminants generated in the enclosed space 92. This contamination may be caused, for example, by the meshing of the crankshaft gear 26 and the transmission gear 30.

[0064] The first radially extending portion 68A of the restricting member 60 protrudes from the outer peripheral portion side of the crankshaft 14 toward the first axial hole 24Aa side of the first carrier 24A, and constitutes a labyrinth seal that partially narrows the radial dimension of the outer passage 94. Here, an example of a so-called direct-through type labyrinth seal is shown in which a part of the labyrinth seal protrudes only from one of the portions facing the outer passage 94 in the radial direction. Thereby, the inflow of contaminants toward the first crank bearing 22A side in the outer passage 94 is inhibited by the first radially extending portion 68A of the restricting member 60, which is advantageous for extending the service life of the first crank bearing 22A. From the viewpoint of effectively inhibiting the inflow of contaminants, the first radially extending portion 68A of the restricting member 60 preferably forms an annular shape that is continuous over the entire circumference around the rotation center line C14 of the crankshaft 14. Also, from the same viewpoint, the first radially extending portion 68A of the restricting member 60 preferably protrudes to a position that axially overlaps with the outer end portion 52a that is axially outside the cage 52, and more preferably protrudes radially outside the outer end portion 52a.

[0065] (Second Embodiment) Refer to FIG. 6. The assembling method of the gear device 10 according to the present embodiment is different from that of the first embodiment in that, in addition to the above-described first assembling step S12, second assembling step S14, and gear assembling step S16, it includes a removing step S18 of removing the restricting member 60 from the crankshaft 14. The removing step S18 is performed between the second assembling step S14 and the gear assembling step S16. The restricting member 60 is removed from the crankshaft 14 by moving it axially outward with respect to the crankshaft 14. Even if the restricting member 60 is removed in this way, in the second assembling step S14, the input-side bearing structure 82 including the first carrier 24A, the first crankshaft bearing 22A, and the crankshaft 14 has been assembled. Therefore, the axial movement of the rolling elements 50 of the first crankshaft bearing 22A axially outward is restricted by the inner ring 56, and the rolling elements 50 do not axially shift outward from the inner ring 56. Thus, it is possible to simplify the configuration of the gear device 10 while suppressing a large axial displacement of the rolling elements 50 on the inner ring 56 during the assembling process. Further, regarding the restricting member 60, it is possible to adopt a structure that can withstand only the restriction of the axial movement of the rolling elements 50 during assembly, and the structure can be simplified.

[0066] (Third Embodiment) Refer to FIG. 7. The gear device 10 according to the present embodiment is different from the gear device 10 of the first embodiment in that it includes a clearance forming member 100 attached to the first carrier 24A. The clearance forming member 100 of the present embodiment includes an axially extending portion 102 fixed to the first axial hole 24Aa of the first carrier 24A by interference fit, and a radially extending portion 104 protruding radially inward from the axially extending portion 66. The radially extending portion 104 of the clearance forming member 100 protrudes from the side of the first axial hole 24Aa of the first carrier 24A toward the outer peripheral portion side of the crankshaft 14.

[0067] The gap forming member 100 cooperates with the restricting member 60 to form a labyrinth gap 106 in the outer passage 94. The labyrinth gap 106 is formed in the outer passage 94 so as to meander radially toward the first crank bearing 22A side while advancing axially inward. To achieve this, the labyrinth gap 106 includes a radial gap 106a and an axial gap 106b that are alternately arranged toward the first crank bearing 22A side in the outer passage 94.

[0068] The radial gap 106a is formed to extend axially. The radial gap 106a is formed between a portion that faces radially with respect to the radially extending portion 104 of the gap forming member 100 (here, the axially extending portion 66 of the restricting member 60) and the radially extending portion 104 of the gap forming member 100. In addition to this, the radial gap 106a is formed between a portion that faces radially with respect to the first radially extending portion 68A of the restricting member 60 (here, the axially extending portion 102 of the gap forming member 100) and the first radially extending portion 68A of the restricting member 60. The axial gap 106b is formed to extend radially. The axial gap 106b is formed between the radially extending portion 104 of the gap forming member 100 and the first radially extending portion 68A of the restricting member 60. By forming such a labyrinth gap 106, the inflow of contaminants toward the first crank bearing 22A side in the outer passage 94 can be significantly reduced.

[0069] The above-described modified forms of the gear device will be described.

[0070] As a specific type of the eccentric swing type gear device, the sorting type has been described as an example. This type is not particularly limited. For example, a center crank type in which the crank shaft 14 is arranged on the swing center C16A of the swing gear 16 may be used. In this case, the crank shaft 14 may serve as an input member.

[0071] Instead of carriers 24A and 24B, the casing 20 may serve as the output member. Instead of the external gear, an internal gear may be used as the oscillating gear 16, and instead of the internal gear, an external gear may be used as the meshing gear 18. The gear device 10 may function as a speed increasing device. In this case, instead of the crankshaft gear 26 (crankshaft 14), carriers 24A, 24B or the casing 20 may be the input member, and instead of carriers 24A, 24B or the casing 20, the crankshaft gear 26 (crankshaft 14) may be the output member.

[0072] So far, an example in which the crankshaft bearings 22A and 22B are separable bearings in which both the outer ring 54 and the inner ring 56 are axially separable with respect to the rolling elements 50 has been described. The crankshaft bearings 22A and 22B only need to be separable bearings in which at least the inner ring 56 is axially separable with respect to the rolling elements 50. The outer ring 54 may be separable not only axially but also radially with respect to the rolling elements 50.

[0073] The restricting member 60 may be attached to the crankshaft 14 on the side axially opposite to the crankshaft gear 26 with respect to the eccentric portion 12 of the crankshaft 14. In this case, in the embodiment, the restricting member 60 can restrict the axial movement of the rolling elements 50 with respect to the inner ring 56 of the second crankshaft bearing 22B. Further, the restricting members 60 may be provided individually corresponding to the first crankshaft bearing 22A and the second crankshaft bearing 22B, respectively. In this case, the individual restricting members 60 are provided to restrict the axial movement of the rolling elements 50 of the corresponding crankshaft bearings 22A and 22B.

[0074] An example in which the restricting member 60 includes the hard component 62 and the soft component 64 has been described, but the restricting member 60 may include only the hard component 62. In this case, the contact portion 70 of the restricting member 60 only needs to be provided on the hard component 62.

[0075] The specific method for attaching the restricting member 60 to the crankshaft 14 is not particularly limited. The restricting member 60 may be attached to the crankshaft 14 by fitting it into a groove provided in the outer peripheral portion of the crankshaft 14. In this case, the restricting member 60 may be loosely fitted, press-fitted, or the like into the crankshaft 14.

[0076] The specific shape of the restricting member 60 is not particularly limited. For example, the restricting member 60 does not necessarily need to include a positioning portion 72 that is positioned with respect to the crankshaft 14. Also, the position of the positioning portion 72 of the restricting member 60 is not particularly limited. For example, when the restricting member 60 is constituted by a retaining ring, it may be constituted by its inner peripheral end portion.

[0077] An axial clearance 76 does not necessarily need to be provided between the first crank bearing 22A and the restricting member 60.

[0078] The second carrier 24B among the first carrier 24A and the second carrier 24B may not be provided. In this case, in the above-described assembly method, only the second assembly step S14 among the first assembly step S12 and the second assembly step S14 needs to be performed. Also, when the eccentric swing type gear device is of a center crank type without the crankshaft gear 26, the gear assembly step S16 does not exist in the above-described assembly method.

[0079] The restricting member assembly step S10 of assembling the rolling elements 50 of the first crank bearing 22 and the restricting member 60 to the crankshaft 14 may be performed prior to the second assembly step S14. As an example of this, the restricting member assembly step S10 was described as being performed prior to the first assembly step S12, but it may also be performed between the first assembly step S12 and the second assembly step S14.

[0080] In the embodiment, an example in which the first assembly step S12 and the second assembly step S14 are performed in this order has been described. However, the second assembly step S14 and the first assembly step S12 may be performed in this order. In this case, in the second assembly step S14, after placing the first carrier 24A with the output side facing upward on the workbench 86, the rolling element unit 58 may be arranged on the outer ring 54 of the first crank bearing 22A integrated with the first carrier 24A, and the rolling elements 50 may be assembled to the first carrier 24A. Further, in this case, in the second insertion step S14A of the second assembly step S14, in this state, the crankshaft 14 integrated with the inner ring 56 of the first crank bearing 22 may be moved downward in the vertical direction, and the input side shaft portion 28A of the crankshaft 14 may be inserted into the first shaft hole 24Aa.

[0081] The above embodiments and modified forms are examples. The technical ideas abstracted from these should not be construed as being limited to the contents of the embodiments and modified forms. Many design changes such as changes, additions, and deletions of components are possible for the contents of the embodiments and modified forms. In the foregoing embodiments, regarding the contents for which such design changes are possible, the notation "embodiment" is added for emphasis. However, design changes are also permitted for the contents without such notation. The hatching attached to the cross-section of the drawing does not limit the material of the object to which the hatching is attached. Structures and numerical values mentioned in the embodiments and modified forms naturally include those that can be regarded as the same considering manufacturing errors and the like. Components configured by a single member in the embodiment may be configured by a plurality of members. Similarly, components configured by a plurality of members in the embodiment may be configured by a single member.

Explanation of Reference Numerals

[0082] 10... Eccentric swing type gear device, 12... Eccentric portion, 14... Crankshaft, 22A... First crank bearing, 22B... Second crank bearing, 24A... First carrier, 24B... Second carrier, 26... Crankshaft gear, 50... Rolling element, 52... Retainer, 54... Outer ring, 56... Inner ring, 60... Restricting member, 62... Hard component, 64... Soft component, 70... Contact portion, 72... Positioning portion, 76... Axial clearance.

Claims

1. A crankshaft having an eccentric portion, and a crankshaft bearing that supports the crankshaft at a position axially displaced with respect to the eccentric portion, comprising: the crankshaft bearing is a separable bearing capable of axially separating an inner ring with respect to rolling elements, an eccentric swing type gear device comprising a regulating member capable of regulating axial movement of the rolling elements with respect to the inner ring when the outer ring of the crankshaft bearing is separated from the rolling elements.

2. The eccentric swing type gear device according to claim 1, wherein the inner ring is integrally provided by the same member as the crankshaft.

3. Comprising a crankshaft gear fixed to the crankshaft, The eccentric swing type gear device according to claim 1, wherein the regulating member is attached to the crankshaft on the same side as the crankshaft gear in the axial direction with respect to the eccentric portion.

4. The eccentric swing type gear device according to claim 1, wherein in a state where the eccentric swing type gear device is assembled, the regulating member is provided at a position that does not contact a cage that holds rolling elements of the crankshaft bearing.

5. The eccentric swing type gear device according to claim 1, wherein the regulating member includes a contact portion with which a cage or the rolling elements of the crankshaft bearing can come into contact, and a positioning portion axially positioned with respect to the crankshaft.

6. The eccentric swing type gear device according to claim 5, wherein the regulating member is fixed to the crankshaft by interference fit.

7. The regulating member includes a contact portion with which a cage or the rolling elements of the crankshaft bearing can come into contact, The regulating member includes a hard component attached to the crankshaft and a soft component softer than the hard component, The eccentric swing type gear device according to claim 1, wherein the contact portion is constituted by the soft component.

8. A crankshaft having an eccentric portion, a first crankshaft bearing that supports the crankshaft at a position axially displaced with respect to the eccentric portion, a first carrier that supports the first crankshaft bearing, comprising: a method of assembling an eccentric swing type gear device, wherein the first crankshaft bearing is a separable bearing capable of axially separating a first inner ring with respect to first rolling elements, a regulating member assembling step of assembling the rolling elements and a regulating member capable of regulating axial movement of the first rolling elements with respect to the first inner ring with respect to the crankshaft integrated with the first inner ring; and an assembling step of assembling a first bearing structure including the crankshaft, the first crankshaft bearing, and the first carrier. The assembly process is performed after the regulating member assembling process. With the regulating member assembled to the crankshaft, the first outer ring of the first crank bearing is assembled to the first rolling element assembled to the crankshaft in an eccentric swing type gear device assembling method.

9. The assembling method of the eccentric swing type gear device according to Claim 8, including a removing process of removing the regulating member from the crankshaft after the assembling process.

10. The eccentric swing type gear device includes a second crank bearing that supports the crankshaft at a position shifted axially opposite to the first crank bearing with respect to the eccentric portion, and a second carrier that supports the second crank bearing. Before the assembling process, it includes another assembling process of assembling a second bearing structure including the crankshaft, the second crank bearing, and the second carrier. The other assembling process is performed after the regulating member assembling process. The crankshaft, to which the first rolling element and the regulating member are assembled and which is integrated with the second inner ring of the second crank bearing, is assembled to the second rolling element of the second crank bearing assembled to the second carrier in the assembling method of the eccentric swing type gear device according to Claim 8.

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