Eccentric oscillating gear device

Abstract

The invention provides an eccentric swing type gear device capable of preventing a limiting component from being clamped between a crankshaft bearing and an eccentric part of a crankshaft. An eccentric oscillating gear device is provided with: a crankshaft (14) having an eccentric section (12A); an eccentric bearing (50A) disposed on the eccentric portion (12A); a restricting member (52A) that restricts the movement of the eccentric bearing (50A) in the axial direction and is provided so as to be rotatable relative to the crankshaft (14); a crankshaft bearing (54A) that is disposed on the opposite side of the regulating member (52A) from the eccentric section (12A) in the axial direction and that supports the crankshaft (14); and a positioning part (56A) which is provided separately from the restricting member (52A), and which is in contact with the crankshaft bearing (54A) from the eccentric part (12) side, thereby positioning the crankshaft bearing (54A) in the axial direction with respect to the crankshaft (14).

Description

[0001] This application claims priority based on Japanese Patent Application No. 2023-191536 filed on November 9, 2023. The entire contents of the Japanese Patent Application are incorporated herein by reference. Technical Field

[0002] The invention relates to an eccentric swing type gear device. Background Art

[0003] Patent document 1 discloses an eccentric swing type gear device, which comprises: a crankshaft having an eccentric portion; an eccentric bearing disposed at the eccentric portion; a limiting member that limits the eccentric bearing from moving in the axial direction; and a crankshaft bearing that is disposed axially on the side of the limiting member opposite to the eccentric portion and supports the crankshaft. In this gear device, an axial gap is provided between the crankshaft bearing and the limiting member, so that the limiting member is provided to be relatively rotatable relative to the crankshaft. Thus, by suppressing the speed difference between the limiting member and the eccentric bearing compared to the case where the limiting member and the crankshaft rotate integrally, wear of the limiting member caused by sliding between the limiting member and the eccentric bearing is suppressed.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2021-28528

[0005] In the disclosed technology of Patent Document 1, the crankshaft bearing is allowed to move axially toward the eccentric portion relative to the crankshaft by the amount of axial clearance between the crankshaft bearing and the limiting component. Therefore, if the crankshaft bearing moves axially toward the eccentric portion, the limiting component may be clamped between the crankshaft bearing and the eccentric portion. In this way, if the limiting component is clamped, the limiting component cannot rotate relative to the crankshaft. In this way, the effect of suppressing the wear of the limiting component, which is the purpose of the disclosed technology of Patent Document 1, cannot be obtained, and therefore it is expected to be improved. Summary of the invention

[0006] One of the objects of the present invention is to provide an eccentric oscillating gear device that can prevent a restricting member from being caught between an eccentric portion of a crankshaft and a crankshaft bearing.

[0007] The eccentric oscillating gear device of the present invention comprises: a crankshaft having an eccentric portion; an eccentric bearing arranged on the eccentric portion; a limiting component that limits the eccentric bearing from moving in the axial direction and is arranged to be able to rotate freely relative to the crankshaft; a crankshaft bearing that is axially arranged on the side of the limiting component opposite to the eccentric portion and supports the crankshaft; and a positioning component that is arranged between the eccentric portion and the crankshaft bearing in a state separate from the limiting component and positions the crankshaft bearing in the axial direction relative to the crankshaft.

[0008] According to the present invention, it is possible to avoid the restriction member being caught between the eccentric portion of the crankshaft and the crankshaft bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a side cross-sectional view showing the gear device according to the embodiment.

[0010] Figure 2 It is magnified Figure 1 A magnified view of a portion of .

[0011] Figure 3 It is magnified Figure 2 A magnified view of a portion of .

[0012] In the figure: 10-eccentric swing type gear device, 12A, 12B-eccentric part, 14-crankshaft, 50A, 50B-eccentric bearing, 52A, 52B-limiting part, 54A, 54B-crankshaft bearing, 56A, 56B-positioning part, 68-positioning part, 70-inner part, 72-axially opposite part. DETAILED DESCRIPTION

[0013] Hereinafter, an embodiment of an eccentric oscillating gear device (hereinafter, also referred to as a gear device) of the present invention will be described. Hereinafter, the same or equivalent elements are marked with the same symbols, and repeated descriptions are omitted. In each of the drawings, for the convenience of description, the constituent elements are appropriately omitted, enlarged, or reduced. The drawings are viewed according to the direction of the symbols.

[0014] refer to Figure 1 The gear device 10 is incorporated into the driven machine as a 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.), and transportation equipment (conveyors, vehicles, etc.).

[0015] The gear device 10 includes: a crankshaft 14 having at least one eccentric portion 12A, 12B; a swing gear 16 that is swung by the eccentric portion 12A, 12B; an engaging gear 18 that meshes with the swing gear 16; wheel carriers 22A, 22B that support the crankshaft 14 via crankshaft bearings 54A, 54B; and a housing 24 that is arranged on the radially outer side of the swing gear 16. In this embodiment, a distributed eccentric swing type gear device 10 is described. This type of gear device 10 includes a plurality of crankshafts 14 that are arranged at positions that are offset from the swing center C16A of the swing gear 16 in the radial direction of the swing gear 16, and a crankshaft gear 26 that is provided on at least one crankshaft 14.

[0016] The gear device 10 includes an input component that inputs rotation from an external driving source and an output component that outputs rotation to an external driven component. Here, an example in which the crankshaft gear 26 is the input component and the wheel carrier 22A is the output component is described. The driving source is, for example, a motor, but it can also be a gear motor, an engine, etc. The driven component is, for example, a part of a driven machine.

[0017] The number of crankshafts 14 in this embodiment is three, but only one is shown in the drawing. The plurality of crankshafts 14 are arranged at intervals along the circumferential direction of the swing gear 16. The plurality of crankshafts 14 penetrate the swing gear 16 and the carriers 22A, 22B along the axial direction of the swing gear 16.

[0018] The crankshaft 14 includes at least one (here, two) eccentric portions 12A, 12B and shaft portions 28A, 28B disposed on both sides of the eccentric portions 12A, 12B in the axial direction. The shaft portions 28A, 28B include one side ( Figure 1 The first shaft portion 28A and the other side surface ( Figure 1 The eccentric portions 12A and 12B are provided on the right side of the paper (on the right side of the paper). Hereinafter, for the sake of convenience, one side in the axial direction is referred to as the load side, and the other side in the axial direction is referred to as the opposite side to the load. The first shaft portion 28A is continuous to one end portion 14a of the crankshaft 14 located on the load side, and the second shaft portion 28B is continuous to the other end portion 14b of the crankshaft 14 located on the opposite side to the load. The shaft portions 28A and 28B are circular with the rotation center line C14 of the crankshaft 14 as the center. The eccentric portions 12A and 12B of the present embodiment are integrally formed by the same components as the shaft portions 28A and 28B, but may also be provided separately from the shaft portions 28A and 28B.

[0019] The axis C12 of the eccentric portions 12A and 12B is eccentric with respect to the rotation center line C14 of the crankshaft 14. The eccentric portions 12A and 12B are circular with the axis C12 as the center. The eccentric portions 12A and 12B rotate about the rotation center line C14 of the crankshaft 14, thereby enabling the swing gear 16 to swing. The "swing" here means that the gear center C16B of the swing gear 16 rotates around the swing center C16A. When the number of eccentric portions 12A and 12B is set to M (two in the present embodiment), the eccentric phases of the plurality of eccentric portions 12A and 12B differ by 360° / M. The number of eccentric portions 12A and 12B is not particularly limited, and may be any number from one to more than three.

[0020] The number of crankshaft gears 26 in this embodiment is three, but only one of them is illustrated in the accompanying drawings. The number of crankshaft gears 26 may also be one. A plurality of crankshaft gears 26 are respectively provided on a plurality of crankshafts 14. The crankshaft gears 26 are provided on the shaft portion 28B of the crankshaft 14 by spline connection or the like so as to be able to rotate integrally therewith. A common transmission gear 30 is meshed with the crankshaft gears 26 of each of the plurality of crankshafts 14, and the rotational power of the driving source is distributed to each crankshaft 14 via the transmission gear 30. The transmission gear 30 is provided, for example, on the outer periphery of the output shaft 32 of the driving source.

[0021] In the present embodiment, the swing gear 16 is an external gear and the meshing gear 18 is an internal gear. The swing gear 16 is respectively provided corresponding to the plurality of eccentric portions 12A and 12B, and is supported on the corresponding eccentric portions 12A and 12B via eccentric bearings 50A and 50B. The meshing gear 18 of the present embodiment comprises a meshing gear body 18a integrated with the housing 24 and a plurality of teeth 18b provided on the meshing gear body 18a and meshing with the swing gear 16. The plurality of teeth 18b of the present embodiment are provided integrally with the meshing gear body 18a by the same components as the meshing gear body 18a. In addition, the plurality of teeth 18b may also be composed of a plurality of pins rotatably supported on the meshing gear body 18a.

[0022] The wheel carriers 22A and 22B include a first wheel carrier 22A disposed on the load side relative to the swing gear 16 and a second wheel carrier 22B disposed on the opposite side of the load relative to the swing gear 16. The first wheel carrier 22A and the second wheel carrier 22B are connected together by a pin body 36 that penetrates the swing gear 16. A main bearing 38 is disposed between the housing 24 and the wheel carriers 22A and 22B. The main bearing 38 is, for example, an angular contact ball bearing, but its specific example is not particularly limited, and it may also be composed of a cross roller bearing, a ball bearing, etc.

[0023] Next, an example of the operation of the gear device 10 is described. If the transmission gear 30 rotates based on the output of the driving source, the rotation of the transmission gear 30 is transmitted to at least one crankshaft 14 via the crankshaft gear 26, so that the crankshaft 14 rotates. At this time, the rotation of the transmission gear 30 is transmitted to the crankshaft 14 after being decelerated by the crankshaft gear 26. If the crankshaft 14 rotates, the eccentric parts 12A and 12B of the crankshaft 14 cause the swing gear 16 to swing. If the swing gear 16 swings, the meshing position of the swing gear 16 and the meshing gear 18 changes in the circumferential direction. As a result, every time the crankshaft 14 rotates once, any one of the swing gear 16 and the meshing gear 18 (here, the swing gear 16) rotates, and the rotation component is output to the output member (here, the wheel carrier 22A, 22B). At this time, the input speed input to the crankshaft 14 is output to the output member as the output rotation after being decelerated by the reduction ratio corresponding to the difference in the number of teeth between the swing gear 16 and the meshing gear 18.

[0024] refer to Figure 2 The gear device 10 includes: eccentric bearings 50A, 50B disposed on the eccentric portions 12A, 12B; limiting members 52A, 52B that limit the axial movement of the eccentric bearings 50A, 50B; crankshaft bearings 54A, 54B that are disposed on the axial side of the limiting members 52A, 52B opposite to the eccentric portions 12A, 12B and support the crankshaft 14; and positioning members 56A, 56B that position the crankshaft bearings 54A, 54B relative to the crankshaft 14 in the axial direction.

[0025] The eccentric bearings 50A and 50B include a first eccentric bearing 50A located closest to the load side in the axial direction and a second eccentric bearing 50B located closest to the opposite side of the load in the axial direction among the eccentric bearings 50A and 50B arranged on the crankshaft 14. When there are a plurality of eccentric bearings 50A and 50B as in the present embodiment, the first eccentric bearing 50A and the second eccentric bearing 50B are separately provided. In contrast, when there is only one eccentric bearing 50A and 50B, the first eccentric bearing 50A and the second eccentric bearing 50B are composed of one eccentric bearing.

[0026] The eccentric portions 12A and 12B of the crankshaft 14 include a first eccentric portion 12A for configuring the first eccentric bearing 50A and a second eccentric portion 12B for configuring the second eccentric bearing 50B. When there are a plurality of eccentric portions 12A and 12B as in the present embodiment, the first eccentric portion 12A and the second eccentric portion 12B are separately provided. In contrast, when there is only one eccentric portion 12A and 12B, the first eccentric portion 12A and the second eccentric portion 12B are composed of one eccentric portion.

[0027] The limiting components 52A and 52B include a first limiting component 52A that limits the axial movement of the first eccentric bearing 50A toward the load side and a second limiting component 52B that limits the axial movement of the second eccentric bearing 50B toward the opposite side of the load. The first limiting component 52A is arranged on the radially outer side of the first shaft portion 28A of the crankshaft 14, and the second limiting component 52B is arranged on the radially outer side of the second shaft portion 28B of the crankshaft 14.

[0028] The crankshaft bearings 54A and 54B include a first crankshaft bearing 54A disposed axially on the side of the first restricting member 52A opposite to the first eccentric portion 12A, and a second crankshaft bearing 54B disposed axially on the side of the second restricting member 52B opposite to the second eccentric portion 12B.

[0029] The positioning portions 56A and 56B include a first positioning portion 56A that positions the first crank bearing 54A in the axial direction relative to the crankshaft 14 , and a second positioning portion 56B that positions the second crank bearing 54B in the axial direction relative to the crankshaft 14 .

[0030] The group of the first eccentric portion 12A and the first shaft portion 28A, the first eccentric bearing 50A, the first limiting member 52A, the first crankshaft bearing 54A and the first positioning portion 56A of the crankshaft 14 is referred to as the first group. The group of the second eccentric portion 12B and the second shaft portion 28B, the second eccentric bearing 50B, the second limiting member 52B, the second crankshaft bearing 54B and the second positioning portion 56B of the crankshaft 14 is referred to as the second group. The first group and the second group have the same characteristics and effects except that the positional relationship of the components in the axial direction on the crankshaft 14 is opposite. Hereinafter, reference will be made mainly to the drawings related to the first group ( Figure 3 ) The same features and effects of the first group and the second group are described. The features and effects of the first group described below are also applicable to the second group. In addition, when describing their positional relationship, the axial direction, radial direction, and circumferential direction of the crankshaft 14 are mainly used for description.

[0031] refer to Figure 3 . The eccentric bearings 50A and 50B include a plurality of rolling elements 50a, a retaining frame 50b for retaining the plurality of rolling elements 50a, and an outer ring 50c and an inner ring 50d for the plurality of rolling elements 50a to roll. The rolling elements 50a of the present embodiment are rollers, but are not limited thereto, and various rolling elements such as spheres may also be used. In the present embodiment, the outer ring 50c is formed by the same component as the swing gear 16 and is integrally provided with the swing gear 16, but may also be provided separately from the swing gear 16. In the present embodiment, the inner ring 50d is formed by the same component as the eccentric portions 12A and 12B of the crankshaft 14 and is integrally provided with the eccentric portions 12A and 12B, but may also be provided separately from the eccentric portions 12A and 12B.

[0032] The retainer 50b includes an annular portion 50ba continuous around the rotation center line C14 of the crankshaft 14, a notch 50bb radially penetrating the annular portion 50ba and accommodating the rolling element 50a, and a flange portion 50bc protruding radially inward from the annular portion 50ba. The flange portions 50bc of this embodiment protrude radially inward from both axial ends of the annular portion 50ba.

[0033] The crankshaft bearings 54A and 54B are arranged in bearing holes 62 formed in the wheel carriers 22A and 22B (see also Figure 2 The crankshaft bearings 54A and 54B are disposed between the bearing holes 62 of the wheel carriers 22A and 22B and the shaft portions 28A and 28B of the crankshaft 14, and support the crankshaft 14 rotatably.

[0034] The crankshaft bearings 54A and 54B include a plurality of rolling elements 54a and an outer ring 54b and an inner ring 54c on which the plurality of rolling elements 54a roll. The rolling elements 54a of the present embodiment are tapered rollers, but the specific examples thereof are not particularly limited, and various rolling elements such as spheres and rollers may be used. The outer ring 54b of the present embodiment is provided separately from the wheel carriers 22A and 22B, but it may also be provided integrally with the wheel carriers 22A and 22B by the same components as the wheel carriers 22A and 22B. The inner ring 54c of the present embodiment is provided separately from the crankshaft 14, but it may also be provided integrally with the crankshaft 14 by the same components as the crankshaft 14. The inner ring 54c of the present embodiment is fixed to the shaft portions 28A and 28B of the crankshaft 14 by interference fit.

[0035] The wheel carriers 22A and 22B are provided with bearing restriction members 64 (see also FIG. 6 ) for restricting the crankshaft bearings 54A and 54B from moving in the axial direction toward the side opposite to the eccentric portions 12A and 12B of the crankshaft 14. Figure 2 ) The bearing restriction member 64 of the present embodiment is constituted by a retaining ring fitted into a groove portion of the bearing hole 62 provided in the wheel carrier 22A, 22B, but the specific example is not particularly limited.

[0036] The limiting members 52A and 52B are in an annular shape surrounding the rotation center line C14 of the crankshaft 14. In terms of achieving this, the limiting members 52A and 52B may be continuous over the entire circumference of the rotation center line C14 of the crankshaft 14, or may have a gap in a part. The limiting members 52A and 52B are in a plate shape with the axial direction of the crankshaft 14 as the thickness direction.

[0037] The first limiting member 52A is arranged between the first eccentric portion 12A of the crankshaft 14 and the first eccentric bearing 50A and the first crankshaft bearing 54A. A portion of the first limiting member 52A located on the radial inner side is arranged at a position overlapping with the first eccentric portion 12A of the crankshaft 14 in the axial direction. A portion of the first limiting member 52A located on the radial outer side is arranged at a position overlapping with the first eccentric bearing 50A in the axial direction. A portion of the first limiting member 52A of the present embodiment is arranged at a position overlapping with the retaining frame 50b of the first eccentric bearing 50A in the axial direction, but may also be arranged at a position overlapping only with the rolling element 50a of the first eccentric bearing 50A in the axial direction.

[0038] When the first eccentric bearing 50A is about to move axially toward the first crankshaft bearing 54A side, the first eccentric bearing 50A (here, the retainer 50b of the first eccentric bearing 50A) contacts the first limiting member 52A. Then, the first limiting member 52A moves axially toward the first crankshaft bearing 54A side together with the first eccentric bearing 50A until it contacts the first crankshaft bearing 54A. And, the movement of the first crankshaft bearing 54A in the axial direction toward the side opposite to the first eccentric portion 12A is restricted by the bearing limiting member 64. Therefore, the axial movement of the first limiting member 52A is restricted by the first crankshaft bearing 54A, and thus the axial movement of the first eccentric bearing 50A is restricted by the first limiting member 52A. In this way, the first eccentric bearing 50A contacts the first limiting member 52A, and thus the first limiting member 52A restricts the first eccentric bearing 50A from moving axially toward the first crankshaft bearing 54A side.

[0039] In the present embodiment, the first limiting member 52A limits the movement of the plurality of eccentric bearings 50A and 50B including the first eccentric bearing 50A toward the first crankshaft bearing 54A side (one side in the axial direction). Furthermore, the second limiting member 52B limits the movement of the plurality of eccentric bearings 50A and 50B including the second eccentric bearing 50B toward the second crankshaft bearing 54B side (the other side in the axial direction). The first limiting member 52A and the second limiting member 52B limit the movement of the plurality of eccentric bearings 50A and 50B toward both sides in the axial direction.

[0040] The first limiting member 52A is arranged to be relatively rotatable with respect to the crankshaft 14. To achieve this, in the present embodiment, an axial gap 66 is provided between the first limiting member 52A and at least one of the first crankshaft bearing 54A and the first eccentric portion 12A of the crankshaft 14 (here, the first crankshaft bearing 54A) to allow the first limiting member 52A to move axially with respect to the crankshaft 14. By providing this axial gap 66, the first limiting member 52A is prevented from being sandwiched between the first crankshaft bearing 54A and the first eccentric portion 12A. In addition, in terms of arranging the first limiting member 52A to be relatively rotatable with respect to the crankshaft 14, the first limiting member 52A is supported by the first shaft portion 28A of the crankshaft 14 to be relatively rotatable. In the present embodiment, a first positioning portion 56A is disposed between the first restricting member 52A and the first shaft portion 28A of the crankshaft 14 , and the first restricting member 52A is relatively rotatably supported by the first shaft portion 28A of the crankshaft 14 via the first positioning portion 56A.

[0041] The first positioning portion 56A is provided separately from the first limiting member 52A. The first positioning portion 56A is disposed between the first eccentric portion 12A and the first crankshaft bearing 54A of the crankshaft 14. When the first crankshaft bearing 54A is to move axially toward the first eccentric portion 12A side, the first positioning portion 56A contacts the first crankshaft bearing 54A from the first eccentric portion 12A side, thereby positioning the first crankshaft bearing 54A relative to the crankshaft 14 in the axial direction. The first positioning portion 56A limits the first crankshaft bearing 54A from moving axially toward the first eccentric portion 12A side, thereby positioning the first crankshaft bearing 54A relative to the crankshaft 14 in the axial direction. The first crankshaft bearing 54A is positioned in the axial direction by the first positioning portion 56A, thereby forming the above-mentioned axial gap 66.

[0042] The first positioning portion 56A of the present embodiment includes a positioning component 68 that is separate from the crankshaft 14. In addition, the first positioning portion 56A can also be provided as a whole with the crankshaft 14 by the same component as the crankshaft 14. At this time, the first positioning portion 56A can include a stepped portion protruding radially outward from the outer periphery of the first shaft portion 28A of the crankshaft 14 that is closer to the first crankshaft bearing 54A side than the first eccentric portion 12A of the crankshaft 14. In addition, the first positioning portion 56A can also include both the positioning component 68 and the stepped portion. The positioning component 68 is in a shape (annular, partially notched annular, etc.) that surrounds the crankshaft 14. The positioning component 68 can be fitted into the outer periphery of the first shaft portion 28A of the crankshaft 14 by any one of an interference fit and a clearance fit.

[0043] The first positioning portion 56A includes an inner portion 70 located radially inward of the first restricting member 52A. The first positioning portion 56A of the present embodiment is composed only of the inner portion 70. At least a portion of the inner portion 70 is disposed at a position radially overlapping the first restricting member 52A.

[0044] The first limiting member 52A includes an axially opposed portion 72 that is axially opposed to the axial end face 54d of the first crankshaft bearing 54A, and an outer portion 74 that extends radially outward from the axially opposed portion 72. The axial end face 54d of the first crankshaft bearing 54A here refers to an end face of the first crankshaft bearing 54A that is located closest to the first eccentric portion 12A in the axial direction. In the present embodiment, the axial end face 54d of the first crankshaft bearing 54A is formed by the inner ring 54c of the first crankshaft bearing 54A, but may be formed by the rolling element 54a of the first crankshaft bearing 54A.

[0045] The axial dimension L70 of the inner portion 70 of the first positioning portion 56A is larger than the axial dimension L72 of the axially opposed portion 72 of the first limiting member 52A. Thus, the above-mentioned axial gap 66 can be provided between at least one of the first crankshaft bearing 54A and the first eccentric portion 12A and the axially opposed portion 72 of the first limiting member 52A. In particular, when the first positioning portion 56A is a positioning member 68 that is separate from the crankshaft 14, the above-mentioned axial gap 66 can be provided even if the positioning member 68 is not fixed to the crankshaft 14, which is advantageous in this respect.

[0046] The axial dimension L72 of the axially opposed portion 72 of the first limiting member 52A is preferably 0.5 times or more the axial dimension L70 of the inner portion 70 of the first positioning portion 56A. The advantages thereof are described below. When the first limiting member 52A limits the axial movement of the first eccentric bearing 50A, an axial load acts on the first limiting member 52A, so the first limiting member 52A deforms in a manner inclined relative to the radial direction of the crankshaft 14. In this way, when the first limiting member 52A is about to deform, if the above-mentioned conditions of the axial dimensions L70 and L72 (L72 ≥ 0.5 × L70) are satisfied, the first limiting member 52A is more likely to contact the axial end face 54d of the first crankshaft bearing 54A and the first eccentric portion 12A than when the axial dimension L72 of the first limiting member 52A is less than 0.5 times the axial dimension L70 of the first positioning portion 56A. As a result, it is easy to suppress the deformation of the first limiting member 52A due to the increase of the inclination angle relative to the radial direction. Furthermore, if the above-mentioned conditions are met, the axial movement margin of the first limiting member 52A becomes smaller than the case where the axial dimension L72 of the first limiting member 52A is less than 0.5 times the axial dimension L70 of the first positioning portion 56A. Therefore, as a result, the axial movement margin of the first eccentric bearing 50A can be reduced. In addition, the axial dimension L72 of the axially opposed portion 72 of the limiting members 52A and 52B may also be less than 0.5 times the axial dimension L70 of the inner portion 70 of the positioning member 68. Furthermore, the upper limit value of the axial dimension L72 is, for example, less than the axial dimension L70.

[0047] In the radially overlapping portion of the first limiting member 52A and the first positioning member 56A, the outer diameter R56A of the first positioning member 56A is smaller than the inner diameter R52A of the first limiting member 52A. Here, the outer diameter R56A is slightly smaller than the inner diameter R52A, but is shown as the same in the figure. Thus, a radial gap (not shown) that allows the first positioning portion 56A and the first limiting member 52A to rotate relative to each other can be provided. Moreover, even when a part of the first positioning portion 56A is arranged on the radially inner side of the first limiting member 52A, the limiting members 52A and 52B can be maintained in a state where they can rotate freely relative to the crankshaft 14. It can also be said that the first limiting member 52A can rotate freely not only relative to the crankshaft 14 but also relative to the first positioning member 56A.

[0048] Next, the effect of the above gear device 10 will be described. When the gear device 10 is used, the first crankshaft bearing 54A may sometimes try to move axially toward the first eccentric portion 12A side due to the load acting on the first crankshaft bearing 54A and the crankshaft 14. In addition, when the first crankshaft bearing 54A is pushed toward the first eccentric portion 12A side in order to interference fit the inner ring 54c of the first crankshaft bearing 54A to the first shaft portion 28A of the crankshaft 14, the first crankshaft bearing 54A may sometimes unexpectedly move axially toward the first eccentric portion 12A side to a large extent relative to the crankshaft 14.

[0049] In this way, when the first crankshaft bearing 54A is about to move toward the first eccentric portion 12A side in the axial direction, the first crankshaft bearing 54A contacts the first positioning portion 56A, and thus the first crankshaft bearing 54A is positioned relative to the crankshaft 14 in the axial direction through the first positioning portion 56A. As a result, it is possible to avoid the first limiting member 52A being sandwiched between the first crankshaft bearing 54A and the first eccentric portion 12A, thereby avoiding the occurrence of a situation in which the first limiting member 52A cannot rotate relative to the crankshaft 14 caused by this. Furthermore, it is possible to maintain the state in which the first limiting member 52A can rotate freely relative to the crankshaft 14, so that the following effect can be stably obtained: the first limiting member 52A is suppressed from sliding between the first limiting member 52A and the first eccentric bearing 50A to cause wear of the first limiting member 52A. In addition, the effect of suppressing wear can be obtained by suppressing the rotation speed difference between the first limiting member 52A and the first eccentric bearing 50A compared to the case in which the first limiting member 52A and the crankshaft 14 rotate integrally.

[0050] At least a portion of the first positioning portion 56A is disposed at a position radially inside the first limiting member 52A and radially overlapping therewith. Thus, compared with disposing the first positioning portion 56A at a position axially deviated from the first limiting member 52A further toward the first crankshaft bearing 54A, the interval between the first eccentric portion 12A and the first crankshaft bearing 54A can be reduced, which is beneficial to miniaturization of the overall axial dimension of the gear device 10.

[0051] (A) The first positioning portion 56A includes a positioning component 68 that is separate from the crankshaft 14. Thus, by preparing a plurality of types of positioning components 68 having different axial dimensions, the plurality of types of positioning components 68 can be used as gaskets for adjusting the internal clearance (preload) of the crankshaft bearings 54A and 54B. For example, the larger the axial dimension of the positioning component 68, the more the internal clearance of the crankshaft bearings 54A and 54B can be reduced (the preload can be increased). By using a positioning component 68 having an axial dimension corresponding to the desired internal clearance of the crankshaft bearings 54A and 54B, the desired internal clearance (preload) corresponding to the axial dimension can be adjusted.

[0052] In the above, the effect of the gear device 10 is described by using the relationship with the first group (the first limiting member 52A and the first positioning member 56A, etc.) described above. The same effect can be obtained by using the relationship with the second group (the second limiting member 52B and the second positioning member 56B, etc.). In addition, in terms of the relationship with the effect of (A) described above, it is sufficient that any one of the first positioning member 56A and the second positioning member 56B includes the positioning member 68 that is separate from the crankshaft 14.

[0053] In the above, modifications of the gear device have been described.

[0054] As a specific type of eccentric oscillating gear device, a distributed type eccentric oscillating gear device is described as an example. The type is not particularly limited, and for example, a center crank type in which the crankshaft 14 is arranged on the oscillation center C16A of the oscillating gear 16 may be used. In this case, the crankshaft 14 may serve as an input member.

[0055] The housing 24 may be used as an output member instead of the carriers 22A and 22B. The internal gear may be used as the swing gear 16 instead of the external gear, and the external gear may be used as the meshing gear 18 instead of the internal gear. The gear device 10 may also function as an acceleration device. In this case, the carriers 22A and 22B or the housing 24 may be used as an input member instead of the crankshaft gear 26 (crankshaft 14), and the crankshaft gear 26 (crankshaft 14) may be used as an output member instead of the carriers 22A and 22B or the housing 24.

[0056] In the above, an example in which the gear device 10 includes the first and second restricting members 52A and 52B and the first and second positioning portions 56A and 56B has been described, but the gear device 10 may include only the first restricting member 52A and the first positioning portion 56A.

[0057] The positioning parts 56A and 56B may also be composed of a retaining ring or the like fixed in the axial direction relative to the crankshaft 14. In this case, the first positioning part 56A may be provided at a position deviated from the first limiting member 52A in the axial direction toward the first crankshaft bearing 54A instead of being arranged at a position overlapping with the first limiting member 52A in the radial direction.

[0058] The first positioning portion 56A may also have a portion protruding radially outward from its inner portion 70. In the above, an example in which the outer diameter R56A of the first positioning portion 56A is smaller than the inner diameter R52A of the first limiting member 52A as a whole is described. In addition, the first positioning portion 56A may also have a different outer diameter in a part. For example, the outer diameter of the portion of the first positioning portion 56A that overlaps with the first limiting member 52A in the radial direction may be smaller than the inner diameter R52A of the first limiting member 52A, and the outer diameter of the portion that does not overlap with the first limiting member 52A in the radial direction may be larger than the inner diameter R52A of the first limiting member 52A. The portion of the first positioning portion 56A that does not overlap with the limiting members 52A, 52B in the radial direction is a portion that is axially located closer to the first crankshaft bearing 54A side than the first limiting member 52A.

[0059] The above description describes an example in which the axially facing portion 72 and the outer portion 74 of the first limiting member 52A have the same axial dimensions. The specific shape of the first limiting member 52A is not particularly limited. For example, the axial dimension of the outer portion 74 may be larger than that of the axially facing portion 72.

[0060] The above embodiments and variations are for illustration. These abstracted technical ideas should not be limited by the contents of the embodiments and variations. Regarding the contents of the embodiments and variations, many design changes such as changes, additions, and deletions of constituent elements can be made. In the above embodiments, the content that can make such design changes is emphasized by marking the mark "implementation method". However, it does not mean that design changes are not allowed for content without such a mark. The hatching marked on the cross section of the accompanying drawings is not used to limit the material of the object marked with the hatching. The structures and values ​​mentioned in the embodiments and variations certainly include structures and values ​​that can be regarded as the same when considering manufacturing errors, etc. In the embodiments, the constituent elements composed of a single component can also be composed of multiple components. Similarly, in the embodiments, the constituent elements composed of multiple components can also be composed of a single component.

Claims

1. An eccentric swing type gear device, characterized in that: have: A crankshaft having an eccentric portion; An eccentric bearing, disposed on the eccentric portion; A limiting component, which limits the eccentric bearing from moving in the axial direction and is arranged to be rotatable relative to the crankshaft; a crankshaft bearing arranged on the side of the limiting member opposite to the eccentric portion in the axial direction and supporting the crankshaft; and The positioning portion is provided separately from the restriction member and contacts the crankshaft bearing from the eccentric portion side, thereby positioning the crankshaft bearing relative to the crankshaft in the axial direction.

2. The eccentric oscillating gear device according to claim 1, characterized in that: The positioning portion includes an inner portion located radially inward of the limiting member. At least a portion of the inner portion is arranged at a position overlapping with the restriction member in the radial direction.

3. The eccentric oscillating gear device according to claim 2, characterized in that: The limiting member includes an axially opposed portion axially opposed to an axial end surface of the crankshaft bearing. The axial dimension of the inner portion is larger than the axial dimension of the axially opposed portion.

4. The eccentric oscillating gear device according to claim 3, characterized in that: The axial dimension of the axially opposing portion is greater than or equal to 0.5 times the axial dimension of the inner portion.

5. The eccentric oscillating gear device according to claim 2, characterized in that: In a portion where the restricting member and the inner portion overlap each other in the radial direction, the outer diameter of the positioning portion is smaller than the inner diameter of the restricting member.

6. The eccentric oscillating gear device according to claim 1, characterized in that: The positioning portion includes a positioning component that is separate from the crankshaft.

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