Eccentric oscillating gear device

Abstract

The invention provides an eccentric swing type gear device which is beneficial for preventing rollers from toppling over when the rollers are arranged. An eccentric oscillating gear device is provided with: a crankshaft (14) having an eccentric part (12); a swing gear (16) swingable by the eccentric part (12); and an eccentric bearing (20) disposed between the eccentric part (12) and the oscillating gear (16). The eccentric bearing (20) is provided with a roller group (52) composed of a plurality of rollers (50), and is not provided with a holder for holding the relative positions of the plurality of rollers (50). The crankshaft (14) is provided with a support section (60) capable of restricting the axial movement of the corresponding roller group (52). The bearing part (60) corresponds to an eccentric part (12), and the eccentric part (12) is configured at a position overlapped with the roller group (52) corresponding to the bearing part (60) in the radial direction of the crankshaft (14). The outer diameter dimension (L60) from the center axis (L12) of the eccentric part (12) corresponding to the support part (60) to the outer peripheral end of the support part (60) becomes larger than the circumcircle radius (R52) of the roller group (52) corresponding to the support part (60) in the maximum eccentric direction (Da) of the eccentric part (12).

Description

[0001] This application claims priority based on Japanese Patent Application No. 2024-195973, filed November 8, 2024. The entire contents of that Japanese application are incorporated herein by reference. Technical Field

[0002] This disclosure relates to an eccentric oscillating gear device. Background Technology

[0003] Patent Document 1 discloses an eccentric oscillating gear device comprising: a crankshaft having an eccentric portion; an oscillating gear capable of oscillating via the eccentric portion; and an eccentric bearing disposed between the eccentric portion and the oscillating gear. The crankshaft includes a support portion capable of restricting the axial movement of the eccentric bearing. In the gear device of Patent Document 1, the outer diameter (described later) from the central axis of the eccentric portion to the outer peripheral end of the support portion is smaller than the circumscribed circle radius of the plurality of rolling elements used in the eccentric bearing in the direction of maximum eccentricity of the eccentric portion.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2018-119649

[0005] As eccentric bearings, some bearings are used that have multiple rollers but lack a cage to maintain the relative position of the rollers. In this case, when assembling the gear assembly, it is necessary to arrange the multiple rollers one by one between the eccentric part of the crankshaft and the oscillating gear.

[0006] The inventors of this application recognized that, under the structure of Patent Document 1, there is a problem that the rollers are prone to tipping over during the roller configuration process. If a roller tipps over during the configuration process, it is necessary to remove the tipped roller and reconfigure the rollers, which increases the working time. Summary of the Invention

[0007] Therefore, one object of this disclosure is to provide an eccentric oscillating gear device that helps to suppress roller tipping during roller configuration operations.

[0008] The eccentric oscillating gear device disclosed herein includes: a crankshaft having an eccentric portion; an oscillating gear capable of oscillating via the eccentric portion; and an eccentric bearing disposed between the eccentric portion and the oscillating gear. The eccentric bearing comprises a roller assembly consisting of a plurality of rollers and does not have a cage for maintaining the relative position of the plurality of rollers. The crankshaft includes a support portion capable of restricting axial movement of the corresponding roller assembly, the support portion corresponding to the eccentric portion, the eccentric portion being disposed radially on the crankshaft and overlapping with the roller assembly corresponding to the support portion, and the outer diameter from the central axis of the eccentric portion to the outer peripheral end of the support portion being greater than the circumscribed circle radius of the roller assembly corresponding to the support portion in the direction of maximum eccentricity of the eccentric portion.

[0009] Invention Effects

[0010] According to the eccentric oscillating gear device disclosed herein, it is beneficial to suppress the tipping of the rollers during the roller configuration operation. Attached Figure Description

[0011] Figure 1 This is a side sectional view of the gear device according to the embodiment.

[0012] Figure 2 yes Figure 1 An enlarged view of the gear mechanism.

[0013] Figure 3 (A) represents Figure 2 A partial cross-sectional view of section AA and the first support portion. Figure 3 (B) means Figure 2 A partial BB section and a sectional view of the second support.

[0014] Figure 4 This is an explanatory diagram illustrating the roller configuration operation using the gear device of the embodiment.

[0015] Figure 5 (A) is a side sectional view showing the main part of the gear mechanism in reference mode. Figure 5 (B) means Figure 5 A portion of the CC section of (A) and a sectional view of the first support.

[0016] Figure 6 (A) is an explanatory diagram showing the roller tilt when using a gear mechanism in the reference configuration. Figure 6 (B) indicates from Figure 6 (A) is an explanatory diagram showing the roller tilting when observing the eccentric part and bearing hole in the direction of arrow V.

[0017] In the diagram: 10 - Eccentric oscillating gear device, 12 - Eccentric part, 12A - First eccentric part, 12B - Second eccentric part, 14 - Crankshaft, 16 - Oscillating gear, 16A - First oscillating gear, 16B - Second oscillating gear, 20 - Eccentric bearing, 50 - Roller, 52 - Roller group, 52A - First roller group, 52B - Second roller group, 60 - Support part, 60A - First support part, 60B - Second support part, 64 - Eccentric side region, 66 - Anti-eccentric side region, 72 - Clearance. Detailed Implementation

[0018] The following describes embodiments of the eccentric oscillating gear device for implementing this disclosure. Identical or equivalent elements are labeled with the same reference numerals, and repeated descriptions are omitted. In the figures, for ease of explanation, constituent elements are appropriately omitted, enlarged, or reduced. The figures should be viewed according to the orientation of the symbols.

[0019] refer to Figure 1 An eccentric oscillating gear device 10 (hereinafter referred to as the gear device) is assembled on the main machine. The gear device 10 can drive the driven component (not shown) of the main machine by outputting rotation. The main machine is, for example, (1) industrial machinery such as machine tools and construction machinery; (2) robots such as industrial robots and service robots; (3) conveying equipment such as conveyors; (4) various machines such as vehicles.

[0020] The gear assembly 10 includes a crankshaft 14 with an eccentric portion 12, a oscillating gear 16 that can oscillate via the eccentric portion 12, a meshing gear 18 that meshes with the oscillating gear 16, and an eccentric bearing 20 disposed between the eccentric portion 12 and the oscillating gear 16. Furthermore, the gear assembly 10 also includes a bearing located on one axial side of the oscillating gear 16. Figure 1 The wheel carrier 22 of the first side component (on the left side of the paper) is set as the axial side of the swing gear 16 on the other side. Figure 1 The cover 24 of the second side component (on the right side of the paper) and the housing 26 that at least accommodates the oscillating gear 16. In this specification, the direction along the rotation center line of the crankshaft 14 (hereinafter referred to as the crankshaft axis L14) is simply referred to as the axial direction.

[0021] The eccentric oscillating gear device 10 can rotate one of the oscillating gear 16 and the meshing gear 18 by rotating the input member 28, and the output member 30 is rotated by this rotation component. In this embodiment, an example in which the crankshaft 14 is the input member 28 and the wheel carrier 22 is the output member 30 will be described. The rotation output from an external drive source is input to the input member 28. The drive source is, for example, a motor, a geared motor, or an engine. The output member 30 outputs rotation to the driven components of the external main machine.

[0022] The crankshaft 14 includes at least one eccentric portion 12 and shaft portions 32 disposed on both axial sides of the eccentric portion 12. A first crankshaft bearing 34A is disposed between the shaft portion 32 on one axial side of the eccentric portion 12 and the wheel carrier 22. A second crankshaft bearing 34B is disposed between the shaft portion 32 on the other axial side of the eccentric portion 12 and the housing 24. Details of the crankshaft 14 will be described later.

[0023] One of the oscillating gear 16 and the meshing gear 18 is an external gear, and the other is an internal gear. In this embodiment, the oscillating gear 16 is an external gear. The oscillating gear 16 is rotatably supported on the corresponding eccentric portion 12 via an eccentric bearing 20. The oscillating gear 16 has a bearing hole 16a, and the eccentric bearing 20 is disposed inside the bearing hole 16a. In this embodiment, the meshing gear 18 is disposed on the inner periphery of the housing 26.

[0024] Pin 36 protrudes axially from wheel carrier 22 and passes through oscillating gear 16. Pin 36 enables the rotational component of wheel carrier 22 and oscillating gear 16 to be synchronized. In this embodiment, pin 36 contacts pin hole 16b of oscillating gear 16 via roller 38 rotatably supported on pin 36, but direct contact is also possible.

[0025] In addition to housing the oscillating gear 16, the outer casing 26 also houses the crankshaft 14, wheel carrier 22, etc. In this embodiment, the outer casing 26 is composed of multiple outer casing components 40 connected by bolts or the like, but it can also be composed of a single component. In this embodiment, one outer casing component 40 also serves as the cover 24. A main bearing 42 is disposed between the wheel carrier 22 and the outer casing 26.

[0026] refer to Figure 2 In this figure, cross-sectional lines are omitted for ease of explanation. In this embodiment, the eccentric portion 12 of the crankshaft 14 and the central side portion located on the crank axis L14 relative to the eccentric portion 12 are integrally formed from the same component, but they can also be separately formed. The eccentric portion 12 has a circular shape with its central axis L12 eccentric relative to the crank axis L14. The eccentric portion 12 can cause the oscillating gear 16 to oscillate by rotating around the crank axis L14. Here, "oscillation" refers to the movement of the oscillating gear 16 as a whole, with its central axis L16 revolving around the oscillation center Ca. The direction from the crank axis L14 toward the central axis L12 of the eccentric portion 12 is called the maximum eccentricity direction Da of the eccentric portion 12. Furthermore, the direction from the central axis L12 of the eccentric portion 12 toward the direction directly opposite to the maximum eccentricity direction Da is called the anti-maximum eccentricity direction Db of the eccentric portion 12.

[0027] In this embodiment, the number of eccentric portions 12 is two, but it is not limited to this; it can be any number, from one to three or more. When the number of eccentric portions 12 is set to M, the eccentric phases of the multiple eccentric portions 12 are offset from each other by an amount of 360° / M. Here, the eccentric phase refers to the phase on the maximum eccentric direction Da of the eccentric portion 12, determined according to the angle around the crank axis L14.

[0028] The crankshaft 14 may have a flange portion 14c protruding radially outward from its outer periphery. In this embodiment, the flange portion 14c and the central side portion located on the crankshaft axis L14 side relative to the flange portion 14c are integrally provided with the same component, but they may also be separately provided. The flange portion 14c is provided between adjacent eccentric portions 12 in the arrangement sequence of the plurality of eccentric portions 12.

[0029] The eccentric bearing 20 includes a roller assembly 52 consisting of a plurality of rollers 50. A roller receiving space 54 for accommodating the roller assembly 52 is provided between the bearing bore 16a of the oscillating gear 16 and the eccentric portion 12. The eccentric bearing 20 is a bearing without a cage to maintain the relative position of the plurality of rollers 50. As described later, this bearing refers to a bearing in which the plurality of rollers 50 need to be arranged in the roller receiving space 54 during the assembly of the gear assembly 10. In this embodiment, a full roller bearing is used, which accommodates the maximum number of rollers 50 that can be filled in the roller receiving space 54. Alternatively, a bearing can be used that accommodates fewer than the maximum number of rollers 50 that can be filled in the roller receiving space 54. Furthermore, a bearing in which spacers are arranged between a portion of the adjacent rollers 50 in the arrangement sequence of the plurality of rollers 50 can be used.

[0030] Thus, by using a bearing without a cage as the eccentric bearing 20, the space for the cage can be utilized as space for the rollers, thereby helping to ensure the roller fill factor. In particular, when miniaturizing the gear assembly 10, there are limitations to miniaturizing the size of the cage in the circumferential direction of the crankshaft 14 during manufacturing, resulting in a problem where the roller fill factor is reduced due to the influence of the cage. By omitting the cage, which causes this reduction in roller fill factor, it is possible to miniaturize the gear assembly 10 while ensuring the roller fill factor.

[0031] In this embodiment, the rotation axis of the roller 50 extends axially. The eccentric bearing 20 of this embodiment does not have a dedicated inner ring; the outer peripheral surface of the eccentric portion 12 serves as the inner ring. Furthermore, the eccentric bearing 20 of this embodiment does not have a dedicated outer ring; the inner peripheral surface of the bearing bore 16a serves as the outer ring. Alternatively, the eccentric bearing 20 may have either a dedicated inner ring fixed to the outer peripheral surface of the eccentric portion 12 or a dedicated outer ring fixed to the bearing bore 16a.

[0032] refer to Figure 2 , Figure 3 (A) and Figure 3 (B) The crankshaft 14 includes a support portion 60, which restricts the axial movement of the corresponding roller group 52 by supporting the end faces of each roller 50 of the corresponding roller group 52. The support portion 60 is generally flat and orthogonal to the axial direction. The support portion 60 includes a first support portion 60A and a second support portion 60B, with the second support portion 60B facing the side opposite to the first support portion 60A in the axial direction. In this embodiment, the first support portion 60A is provided on one side of the flange portion 14c, and the second support portion 60B is provided on the side of the flange portion 14c on the side opposite to the first support portion 60B in the axial direction.

[0033] The roller assembly 52 includes a first roller assembly 52A corresponding to the first support portion 60A and a second roller assembly 52B corresponding to the second support portion 60B. The first support portion 60A can restrict the axial movement of the corresponding first roller assembly 52A, and the second support portion 60B can restrict the axial movement of the corresponding second roller assembly 52B. The eccentric portion 12 includes a first eccentric portion 12A corresponding to the first support portion 60A and a second eccentric portion 12B corresponding to the second support portion 60B. The first eccentric portion 12A and the second eccentric portion 12B are different in eccentric phase. The oscillating gear 16 includes a first oscillating gear 16A corresponding to the first support portion 60A and a second oscillating gear 16B corresponding to the second support portion 60B. The first eccentric portion 12A and the first oscillating gear 16A are arranged at a position that overlaps with the first roller assembly 52A corresponding to the first support portion 60A in the radial direction of the crankshaft 14. The second eccentric portion 12B and the second oscillating gear 16B are arranged at a position that overlaps radially with the second roller group 52B corresponding to the corresponding second seat portion 60B on the crankshaft 14.

[0034] A first pressing member 62A is disposed on the side of the first roller group 52A opposite to the first support portion 60A in the axial direction. The first pressing member 62A restricts the axial movement of the first roller group 52A to the side opposite to the first support portion 60A. A second pressing member 62B is disposed on the side of the second roller group 52B opposite to the second support portion 60B in the axial direction. The second pressing member 62B restricts the axial movement of the second roller group 52B to the side opposite to the second support portion 60B.

[0035] The support portion 60 has an eccentric side region 64 and an anti-eccentric side region 66. The eccentric side region 64 is a half-circumference region located on the side of the maximum eccentric direction Da of the corresponding eccentric portion 12 relative to the central axis L12. The anti-eccentric side region 66 is a half-circumference region located on the side of the opposite maximum eccentric direction Db of the eccentric portion 12 relative to the central axis L12.

[0036] In this embodiment, the radial outer diameter radius R60 of the crankshaft 14 from the crankshaft axis L14 to the outer peripheral end of the support portion 60 is the same size throughout the entire circumference surrounding the crankshaft axis L14. Here, "outer peripheral end of the support portion 60" refers to the outer peripheral end of the part that can contact the surface of the roller 50 when the support portion 60 supports the end face of the roller 50 during the roller arrangement operation.

[0037] The radial direction perpendicular to the central axis L12 of the eccentric portion 12 is simply referred to as the radial direction of the eccentric portion 12. Furthermore, the radial dimension of the eccentric portion 12 from its central axis L12 (corresponding to the support portion 60) to the outer peripheral end of the support portion 60 is called the outer diameter L60 of the support portion 60 based on the eccentric portion 12. In this embodiment, the outer diameter L60 of the support portion 60 based on the eccentric portion 12 is smallest in the maximum eccentricity direction Da of the eccentric portion 12 and largest in the opposite maximum eccentricity direction Db of the eccentric portion 12. Figure 2 and Figure 3 The minimum outer diameter dimension L60 is shown in the figure. The outer diameter dimension L60 of the support portion 60 gradually decreases in the circumferential direction around the central axis L12 of the eccentric portion 12 from the anti-maximum eccentricity direction Db toward the maximum eccentricity direction Da.

[0038] The radius of the circumscribed circle 56 of the roller assembly 52 corresponding to the support portion 60 is called the circumscribed circle radius R52 of the roller assembly 52. ​​The circumscribed circle radius R52 is the same size throughout the entire circumference surrounding the central axis L12 of the eccentric portion 12 corresponding to the support portion 60. The circumscribed circle radius R52 is provided on the bearing bore 16a side relative to the roller assembly 52, and is the inner radius of the circular rolling surface on which the roller assembly 52 rolls. In this embodiment, the rolling surface is provided in the bearing bore 16a, but it may also be provided on the outer ring of the eccentric bearing 20 fixed to the bearing bore 16a.

[0039] Here, the outer diameter L60 of the support portion 60, based on the eccentric portion 12, is larger than the circumscribed circle radius R52 of the roller group 52 corresponding to the support portion 60 in the maximum eccentric direction Da of the eccentric portion 12. Furthermore, the outer diameter L60 of the support portion 60 is larger than the circumscribed circle radius R52 of the roller group 52 corresponding to the support portion 60 in both the eccentric side region 64 and the anti-eccentric side region 66. A detailed explanation will follow.

[0040] refer to Figure 3(A). The outer diameter L60 of the first support portion 60A, based on the first eccentric portion 12A, is greater than the circumscribed circle radius R52 of the first roller group 52A corresponding to the first support portion 60A in the maximum eccentric direction Da of the first eccentric portion 12A. The outer diameter L60 of the first support portion 60A is also greater than the circumscribed circle radius R52 of the first roller group 52A in its eccentric side region 64. To satisfy this condition, the outer diameter L60 is greater than the circumscribed circle radius R52 in at least a majority of its eccentric side region 64. Furthermore, the outer diameter L60 of the first support portion 60A is greater than the circumscribed circle radius R52 of the first roller group 52A in its anti-eccentric side region 66. To satisfy this condition, the outer diameter L60 is greater than the circumscribed circle radius R52 in at least a majority of its anti-eccentric side region 66. In this specification, "majorly" refers to more than 90% of the circumferential range of the mentioned area surrounding the central axis L12 of the mentioned eccentric portion 12. In this embodiment, the outer diameter L60 of the first support portion 60A is larger than the circumscribed circle radius R52 in the entire regions of the eccentric side region 64 and the anti-eccentric side region 66, respectively.

[0041] refer to Figure 3 (B). The outer diameter L60 of the second support portion 60B, based on the second eccentric portion 12B, is greater than the circumscribed circle radius R52 of the second roller group 52B corresponding to the second eccentric portion 12B in the maximum eccentric direction Da of the second eccentric portion 12B. The outer diameter L60 of the second support portion 60B is greater than the circumscribed circle radius R52 of the second roller group 52B in its eccentric side region 64. To satisfy this condition, the outer diameter L60 is greater than the circumscribed circle radius R52 in at least a majority of the eccentric side region 64. Furthermore, the outer diameter L60 of the second support portion 60B is greater than the circumscribed circle radius R52 of the second roller group 52B in its anti-eccentric side region 66. To satisfy this condition, the outer diameter L60 is greater than the circumscribed circle radius R52 in at least a majority of the anti-eccentric side region 66. In this embodiment, the outer diameter L60 of the second support portion 60B is greater than the circumscribed circle radius R52 in the entire regions of the eccentric side region 64 and the anti-eccentric side region 66.

[0042] The component that overlaps with the support portion 60 radially in the crankshaft 14 and is closest to the support portion 60 is called the nearest-position component. In this embodiment, the nearest-position component is the roller 38 (see reference). Figure 2 However, it is not limited to this; it can also be pin 36, etc. The outer diameter radius R60 of each support 60 is smaller than the radial dimension from the crank axis L14 of the crankshaft 14 on which the support 60 is provided to the crankshaft 14 of the nearest position member, so as to avoid contact with the nearest position member.

[0043] An example of the assembly steps of the gear assembly 10 described above will be explained. First, the crankshaft 14 is inserted into the bearing bore 16a of each oscillating gear 16. Then, rollers 50 are arranged in the roller receiving space 54 between the crankshaft 14 and each oscillating gear 16, thereby obtaining the gear assembly (described later). Then, the wheel carrier 22 is assembled for the gear assembly via the first crankshaft bearing 34A. Then, the housing 26 and the wheel carrier 22 are assembled for the gear assembly via the second crankshaft bearing 34B. Thus, the gear assembly 10 is assembled.

[0044] When assembling the gear assembly 10, using an eccentric bearing 20 without a cage, the operation of arranging each roller 50 of the roller group 52 in the roller receiving space 54 between the eccentric portion 12 of the crankshaft 14 and the oscillating gear 16 is performed. In this roller 50 arrangement operation, each roller 50 of the roller group 52 is arranged one by one in the corresponding roller receiving space 54. The roller 50 arrangement operation includes a first step of arranging each roller 50 of the first roller group 52A in the roller receiving space 54 and a second step of arranging each roller 50 of the second roller group 52B in the roller receiving space 54.

[0045] refer to Figure 4 In the first step, a roller mounting operation is performed as follows: with the roller receiving space 54 accommodating the first roller group 52A positioned above the first support portion 60A, each roller 50 of the first roller group 52A is inserted into the roller receiving space 54 from above, and the roller 50 is mounted on the first support portion 60A. By performing the roller mounting operation on each roller 50 of the first roller group 52A, the first roller group 52A is positioned in the roller receiving space 54. Then, in order to prevent the first roller group 52A from falling out of the roller receiving space 54, a first pressing member 62A is provided to restrict the axial movement of the first roller group 52A.

[0046] Then, although not shown, the second process is performed after the crankshaft 14 and each oscillating gear 16 are flipped up and down. In the second process, a roller mounting operation is performed as follows: with the roller receiving space 54 accommodating the second roller group 52B positioned above the second support portion 60B, each roller 50 of the second roller group 52B is inserted into the roller receiving space 54 from above, and the rollers 50 are mounted on the second support portion 60B. By performing the roller mounting operation on each roller 50 of the second roller group 52B, the second roller group 52B is positioned in the roller receiving space 54. Then, to prevent the second roller group 52B from falling out of the roller receiving space 54, a second pressing member 62B is provided to restrict the axial movement of the second roller group 52B. The gear assembly is thus obtained.

[0047] Next, the background to the design of the gear device of this disclosure will be explained in conjunction with the effects of the gear device 10 of this embodiment. Figure 5 (A) is a side sectional view showing the main part of the gear mechanism in reference mode. Figure 5 (B) means Figure 5 A portion of the CC section of (A) and a cross-sectional view of the first support portion 60A. The gear device in the reference configuration differs from that in the embodiment only in the outer diameter L60 of each support portion 60 of the crankshaft 14.

[0048] In the gear mechanism of the reference embodiment, such as Patent Document 1, the outer diameter L60 of the support portion 60, based on the eccentric portion 12, is smaller than the circumscribed circle radius R52 of the roller set 52 in the maximum eccentric direction Da of the eccentric portion 12. Furthermore, in the gear mechanism of the reference embodiment, the outer diameter L60 of the support portion 60 is smaller than the circumscribed circle radius R52 throughout its eccentric side region 64, and smaller than the circumscribed circle radius R52 in a portion of its anti-eccentric side region 66. At this time, as... Figure 6 As shown in (A), during the arrangement of the roller 50 described above, it is difficult to place the roller 50 within a wide range in the eccentric side region 64 of the support portion 60 located on the side of the maximum eccentric direction Da of the eccentric portion 12, and the posture of the roller 50 is prone to instability. As a result, the roller 50 is prone to tilting, which can lead to the roller 50 easily tipping over.

[0049] The tilt of roller 50 here refers, for example, to the tilt of roller 50's axis of rotation L50 relative to crank axis L14 as it moves axially away from support 60. (See reference) Figure 6 (B). As shown by the double-dotted line, more precisely, the rotation axis L50 of the roller 50 is arranged axially. Here, the tilting of the roller 50 refers to the state in which its rotation axis L50 is arranged approximately parallel to a plane perpendicular to the axial direction, as shown by the solid line. When arranging the roller 50, assuming that due to an unexpected positional offset La between the central axis L12 of the eccentric portion 12 and the central axis L16a of the bearing hole 16a of the oscillating gear 16, the roller receiving space 54 widens on the side of the maximum eccentric direction Da of the eccentric portion 12. At this time, a wider space is created in the roller receiving space 54 that allows the roller 50 to tilt, and it is difficult to place the roller 50 in a wider range in the eccentric side region 64 of the support portion 60, so the problem of the roller 50 tilting is likely to occur.

[0050] In particular, the smaller the gear assembly 10 becomes, the more prone the roller 50 is to tipping over due to the positional misalignment between the eccentric portion 12 and the bearing bore 16a. This is because, as the gear assembly 10 is miniaturized along with the roller group 52, when the eccentric portion 12 and the bearing bore 16a have the same absolute positional misalignment, the space that allows the roller 50 to tip over due to this misalignment tends to become relatively larger relative to the roller 50. For example, depending on the size of the roller group 52, sometimes the roller 50 can easily tip over if the central axis L12 of the eccentric portion 12 is only offset from the central axis L16a of the bearing bore 16a by 0.1 mm. Furthermore, this problem of roller 50 tipping is more likely to occur when the number of rollers 50 arranged in the roller receiving space 54 is small and the tipping of the rollers 50 cannot be limited by other rollers 50.

[0051] As a countermeasure, in this embodiment, the outer diameter L60 of the support portion 60, based on the eccentric portion 12, is greater than the circumscribed circle radius R52 of the roller assembly 52 in the maximum eccentric direction Da of the eccentric portion 12. Therefore, as... Figure 4 As shown, compared to the case where this condition is not met, when performing the above-described roller 50 arrangement operation, the roller 50 is more easily placed within a wider area of ​​the eccentric side region 64 of the support portion 60, and the posture of the roller 50 is more easily stabilized. Furthermore, when performing the roller 50 arrangement operation, it is beneficial to suppress the tipping of the roller 50. For example, in Figure 4 In the middle, although the central axis L12 of the eccentric part 12 and the central axis L16a of the bearing hole 16a are in harmony... Figure 6 The same positional offset La is offset, but by placing the roller 50 in a wider range of the eccentric side region 64 of the support 60, the roller 50 exhibits a stable posture.

[0052] In this embodiment, the outer diameter L60 of the support portion 60, based on the eccentric portion 12, is larger than the circumscribed circle radius R52 of the roller assembly 52 in the eccentric side region 64. Therefore, compared to cases where this condition is not met, when arranging the rollers 50, it is easier to mount the rollers 50 on the support portion 60 over a wider area of ​​the eccentric side region 64. Furthermore, during the arrangement of the rollers 50, it is more advantageous to suppress the tipping of the rollers 50.

[0053] In this embodiment, the outer diameter L60 of the support portion 60, based on the eccentric portion 12, is larger than the circumscribed circle radius R52 of the roller assembly 52 in the anti-eccentric side region 66. Therefore, compared to cases where this condition is not met, during the roller arrangement operation, the rollers 50 can be easily mounted on the support portion 60 within a wider range in both the eccentric side region 64 and the anti-eccentric side region 66. Furthermore, during the roller arrangement operation, it is more advantageous to suppress the tipping of the rollers 50.

[0054] In this embodiment, the outer diameter L60 of the first support portion 60A is greater than the circumscribed circle radius R52 of the first roller group 52A in the maximum eccentric direction Da of the first eccentric portion 12A. Furthermore, the outer diameter L60 of the second support portion 60B is greater than the circumscribed circle radius R52 of the second roller group 52B in the maximum eccentric direction Da of the second eccentric portion 12B. Therefore, compared to the case where the condition related to the outer diameter L60 of the first support portion 60A is not met, during operation of arranging the rollers 50 belonging to the first roller group 52A, the rollers 50 are more easily mounted on the first support portion 60A over a wider area of ​​the eccentric side region 64 of the first support portion 60A, and it is beneficial to suppress the tipping of the rollers 50. Furthermore, compared to cases where the conditions related to the outer diameter L60 of the second support portion 60B are not met, when configuring the rollers 50 belonging to the second roller group 52B, the rollers 50 are more easily mounted on the second support portion 60B over a wider area of ​​the eccentric side region 64 of the second support portion 60B, and this helps to suppress the tipping of the rollers 50. In other words, when configuring the rollers 50 belonging to either the first roller group 52A or the second roller group 52B, it also helps to suppress the tipping of the rollers 50.

[0055] The above-mentioned effect of preventing the roller 50 from tipping over is effective when the gear device 10 is miniaturized along with the miniaturization of the roller assembly 52. ​​Related to this effect, the circumscribed circle radius R52 of the roller assembly 52 can, for example, be set to 10 mm or less.

[0056] Next, other features of the gear device 10 of this embodiment will be described. (See reference...) Figure 1 The gear assembly 10 includes a spacer 70 that positions the oscillating gear 16 axially between the wheel carrier 22 and the housing 24. In this embodiment, the spacer 70 includes a first spacer 70A disposed between the first oscillating gear 16A and the second oscillating gear 16B, and a second spacer 70B disposed between the second oscillating gear 16B and the housing 24. The first oscillating gear 16A is positioned axially by contacting both the wheel carrier 22 and the first spacer 70A. The second oscillating gear 16B is positioned axially by contacting both the first spacer 70A and the second spacer 70B.

[0057] refer to Figure 2The oscillating gear 16 is axially opposed to the support portion 60 and is disposed relative to the support portion 60 with a gap 72. Specifically, the first oscillating gear 16A is axially opposed to the first support portion 60A and is disposed relative to the first support portion 60A with a gap 72. Furthermore, the second oscillating gear 16B is axially opposed to the second support portion 60B and is disposed relative to the second support portion 60B with a gap 72. These gaps 72 can be provided between the support portion 60 and the oscillating gear 16 within the entire circumference of the crankshaft 14's crank axis L14. The oscillating gear 16 is positioned axially by the aforementioned spacer 70, thereby maintaining the state where the support portion 60 and the oscillating gear 16 are separated by a gap 72.

[0058] In the gear device 10 of this embodiment, as described above, the outer diameter L60 of the support portion 60, based on the eccentric portion 12, is increased. A swing gear 16 is provided axially opposite to the support portion 60 over a relatively wide range in the circumferential direction surrounding the crankshaft 14. Therefore, assuming the swing gear 16 contacts the support portion 60, the increased outer diameter L60 of the support portion 60 may lead to problems such as power loss due to increased frictional resistance between the swing gear 16 and the support portion 60.

[0059] In this respect, the oscillating gear 16 of this embodiment is provided with an axial gap 72 between it and the axially opposed support portion 60. Therefore, even if the outer diameter L60 of the support portion 60 is increased, the increase in frictional resistance caused by the contact between the support portion 60 and the oscillating gear 16 can be avoided. In particular, in this embodiment, the first oscillating gear 16A and the second oscillating gear 16B are provided with an axial gap 72 between them and different axially opposed support portions 60A and 60B, respectively. Therefore, even if the outer diameter L60 of each support portion 60A and 60B is increased, the increase in frictional resistance caused by the contact between each support portion 60A and 60B and the first oscillating gear 16A and the second oscillating gear 16B can be avoided, which is advantageous.

[0060] Next, variations of the constituent elements described so far will be explained.

[0061] As a specific type of eccentric oscillating gear device 10, a central crank type in which a crankshaft 14 is arranged on the oscillation center Ca of the oscillating gear 16 is described. This type is not particularly limited; for example, it can be a distributed type in which multiple crankshafts 14 are arranged at positions radially offset from the oscillation center Ca of the oscillating gear 16.

[0062] The housing 26 can be used as the output component 30 instead of the wheel carrier 22. The eccentric oscillating gear device 10 of this embodiment has been described as an external tooth oscillating type where the external gear is the oscillating gear 16. Alternatively, the eccentric oscillating gear device 10 can be an internal tooth oscillating type where the internal gear is the oscillating gear 16. In this embodiment, an example of the gear device 10 functioning as a speed reduction device has been described, but it can also function as a speed increase device. In this case, the wheel carrier 22 or housing 26 can be used as the input component 28 instead of the crankshaft 14, and the crankshaft 14 can be used as the output component 30 instead of the wheel carrier 22 or housing 26.

[0063] The outer diameter L60 of the support portion 60 may be greater than the circumscribed circle radius R52 of the roller group 52 only in the maximum eccentric direction Da of the eccentric portion 12, and less than or equal to that circumscribed circle radius R52 in other locations. Furthermore, the outer diameter L60 of the support portion 60 may be greater than the circumscribed circle radius R52 of the roller group 52 only in the maximum eccentric direction Da and the anti-eccentric side region 66 of the eccentric portion 12, and less than or equal to that circumscribed circle radius R52 in other locations. The outer diameter L60 of the first support portion 60A may be greater than the circumscribed circle radius R52 of the first roller group 52A in the maximum eccentric direction Da of the first eccentric portion 12A, and the outer diameter L60 of the second support portion 60B may be smaller than the circumscribed circle radius R52 of the second roller group 52B in the maximum eccentric direction Da of the second eccentric portion 12B.

[0064] The oscillating gear 16 can contact the support portion 60. To achieve this, a gap 72 is provided only between the first oscillating gear 16A and the first support portion 60A, allowing the second oscillating gear 16B to contact the second support portion 60B. Alternatively, the first oscillating gear 16A can contact the first support portion 60A, and the second oscillating gear 16B can contact the second support portion 60B.

[0065] The components described in the above embodiments are examples. These abstracted technical concepts should not be interpreted as limited to the content of this specification. Many design changes, such as alterations, additions, and deletions, are possible for the components described in the embodiments. The terms "this embodiment" or "implementation" emphasize the aspects allowing for such design changes. However, design changes are also permitted even without such descriptions. Any combination of the above components is also valid. The cross-sectional lines marked on the cross-sections in the drawings do not limit the material of the object marked with the cross-section lines. The structures and values ​​mentioned in the embodiments and variations naturally include structures and values ​​that can be considered the same when considering manufacturing errors, etc. In the descriptions in this specification, a component consisting of a single part can be consisting of multiple parts. Similarly, a component consisting of multiple parts can be consisting of a single part.

Claims

1. An eccentric oscillating gear device, comprising: The crankshaft has an eccentric section; The oscillating gear is capable of oscillation via the eccentric portion; and An eccentric bearing is disposed between the eccentric portion and the oscillating gear. The eccentric bearing has a roller assembly consisting of multiple rollers, but lacks a cage to maintain the relative position of the multiple rollers. The crankshaft includes a support portion capable of restricting the axial movement of the corresponding roller assembly. The support portion corresponds to the eccentric portion, which is positioned radially on the crankshaft and overlaps with the roller assembly corresponding to the support portion. The outer diameter of the eccentric portion from the central axis to the outer peripheral end of the support portion is greater than the circumcircle radius of the roller group corresponding to the support portion in the direction of maximum eccentricity of the eccentric portion.

2. The eccentric oscillating gear device according to claim 1, wherein, The support portion has an eccentric side region, which is a half-circumference region located on the side of the eccentric portion in the direction of maximum eccentricity relative to the central axis of the corresponding eccentric portion. The outer diameter of the support portion is greater than the circumcircle radius of the roller group corresponding to the support portion in the eccentric side region.

3. The eccentric oscillating gear device according to claim 2, wherein, The support portion has an anti-eccentric side region, which is a half-circumference region located on the side of the opposite maximum eccentric direction of the corresponding eccentric portion relative to the central axis of the eccentric portion. The outer diameter of the support portion is greater than the circumcircle radius of the roller group corresponding to the support portion in the anti-eccentric side region.

4. The eccentric oscillating gear device according to claim 1, wherein, The support portion includes a first support portion and a second support portion, the second support portion facing a side opposite to the first support portion in the axial direction. The roller assembly includes a first roller assembly whose axial movement is restricted by the first support portion and a second roller assembly whose axial movement is restricted by the second support portion. The eccentric portion includes a first eccentric portion corresponding to the first support portion and a second eccentric portion corresponding to the second support portion. The outer diameter of the distance from the central axis of the first eccentric portion to the outer peripheral end of the first support portion is greater than the circumscribed circle radius of the first roller group in the direction of maximum eccentricity of the first eccentric portion. The outer diameter from the central axis of the second eccentric portion to the outer peripheral end of the second support portion is greater than the circumscribed circle radius of the second roller group in the direction of maximum eccentricity of the second eccentric portion.

5. The eccentric oscillating gear device according to claim 1, wherein, The oscillating gear is axially opposed to the support portion and is disposed with a gap relative to the support portion.

6. The eccentric oscillating gear device according to claim 5, wherein, The support portion includes a first support portion and a second support portion, the second support portion facing a side opposite to the first support portion in the axial direction. The oscillating gear includes a first oscillating gear that is axially opposed to the first support portion and a second oscillating gear that is axially opposed to the second support portion. The first oscillating gear is disposed with a gap relative to the first support portion. The second oscillating gear is disposed with a gap relative to the second support portion.

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