Eccentric oscillating gear device

Abstract

The present invention addresses the problem of better suppressing the entry of dust into a bearing. An eccentric oscillating gear device (1) is provided with: external gears (22A, 22B) provided with offset holes at positions offset from the center; a crankshaft (21) that is inserted into the offset hole and has eccentric bodies (21A, 21B) that oscillate the external gears (22A, 22B); crankshaft bearings (26, 27) for supporting the crankshaft (21); an eccentric body bearing (25) disposed between the external gears (22A, 22B) and the eccentric bodies (21A, 21B); and a spacer (4) disposed on a side portion of the crankshaft bearings (26, 27). The spacer (4) prevents abrasive powder from entering at least one of the crankshaft bearings (26, 27) and the eccentric body bearing (25).

Description

[0001] This application claims priority based on Japanese Patent Application No. 2023-205041 filed on December 5, 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] Conventionally, a so-called distributed eccentric oscillating gear device is known (for example, see Patent Document 1). In the distributed eccentric oscillating gear device, a crankshaft having an eccentric body for oscillating an oscillating gear (external gear) is arranged at a position offset from the center.

[0004] In a distributed eccentric oscillating gear device, the distance from the meshing portion of the external gear to the eccentric body bearing or the crankshaft bearing is relatively short. Therefore, abrasive powder (dust) generated in the meshing portion of the external gear may enter the bearing, thereby shortening the life of the bearing.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2023-4083 Summary of the invention

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress the intrusion of dust into a bearing.

[0007] The present invention provides an eccentric swing type gear device, which comprises: an external gear, which is provided with an offset hole at a position offset from the center; a crankshaft, which is inserted into the offset hole and has an eccentric body that causes the external gear to swing; a crankshaft bearing, which supports the crankshaft; and an eccentric body bearing, which is arranged between the external gear and the eccentric body, the eccentric swing type gear device has a spacer arranged on the side of the crankshaft bearing, and the spacer prevents abrasive powder from entering at least one of the crankshaft bearing and the eccentric body bearing.

[0008] According to the present invention, it is possible to better suppress the intrusion of dust into the bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a longitudinal sectional view of the eccentric oscillating gear device according to the embodiment.

[0010] Figure 2 yes Figure 1 Enlarged view of the R section.

[0011] Figure 3 It is a diagram showing changes in the hole portion of the first spacer according to the embodiment.

[0012] Figure 4It is a diagram for explaining a modified example of the first spacer according to the embodiment.

[0013] In the figure: 1-eccentric oscillating gear device, 4-spacer, 21-crankshaft, 21A, 21B-eccentric body, 22a-step portion, 22A-first external gear, 22B-second external gear, 23-distribution gear, 24-output shaft, 25-eccentric body bearing, 26, 27-crankshaft bearing, 26b-inner ring, 26e-notch portion, 28, 29-main bearing, 28b-inner ring, 28d- Retaining frame, 28e-connecting channel, 30-housing, 32-internal gear, 41-first spacer, 41a-inner diameter portion, 41b-flattened bent portion (first obstruction portion, extension portion), 41c-outer diameter portion (second obstruction portion), 41d-hole portion, 42-second spacer, 42a-inner diameter portion, 42b-U-shaped portion (concave portion), 221-step portion, Ax2-center axis, P-grease chamber. DETAILED DESCRIPTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0015] [Overall structure of the eccentric oscillating gear device]

[0016] Figure 1 It is a longitudinal sectional view of the eccentric oscillating gear device 1 according to the present embodiment.

[0017] Hereinafter, the direction along the central axis Ax1 in the figure is referred to as the "axial direction". Figure 1 The left side of the load side is called the "load side", and the side opposite to the load side ( Figure 1 The right side of the load is called the "opposite load side".

[0018] like Figure 1 As shown, the eccentric oscillating gear device 1 involved in this embodiment is a so-called distributed eccentric oscillating reducer. Specifically, the eccentric oscillating gear device 1 comprises: a crankshaft (eccentric body shaft) 21 having eccentric bodies 21A and 21B; a first external gear 22A, the eccentric body 21A of the crankshaft 21 is inserted into a through hole (offset hole) offset from the axis (central axis Ax1) of the first external gear 22A; and a second external gear 22B, the eccentric body 21B of the crankshaft 21 is inserted into a through hole (offset hole) offset from the axis of the second external gear 22B.

[0019] The crankshaft 21 has a distribution gear 23 meshing with the output shaft of a motor (not shown), and rotation is input from the input shaft via the distribution gear 23. Through holes of the external gears 22A and 22B are provided at multiple locations (for example, three locations) in the circumferential direction around the central axis Ax1, and multiple crankshafts 21 are passed through. The eccentric bodies 21A and 21B are rotatably arranged in the through holes of the external gears 22A and 22B via eccentric body bearings 25 arranged between the eccentric bodies and the external gears 22A and 22B.

[0020] The eccentric oscillating gear device 1 includes: an output shaft (wheel carrier) 24 disposed on the side of the load side of the external gears 22A and 22B; a support plate 241 fixed to the opposite side of the load of the output shaft 24; and a housing 30 having an internal gear 32 meshing with the external gears 22A and 22B. The crankshaft 21 is supported by crankshaft bearings 26 and 27 disposed between the crankshaft 21 and the support plate 241 and the output shaft 24. The crankshaft bearings 26 and 27 are tapered roller bearings in this embodiment. The housing 30 rotatably supports the support plate 241 and the output shaft 24 via main bearings 28 and 29 disposed between the housing 30 and the support plate 241 and the output shaft 24. The main bearings 28 and 29 are tapered roller bearings in this embodiment. The output shaft 24 is fixed to a driven member not shown.

[0021] According to this structure, in the eccentric oscillating gear device 1, when the rotational motion is transmitted to the crankshaft 21 via the distribution gear 23 by the drive of the motor, the eccentric bodies 21A and 21B rotate, thereby causing the external gears 22A and 22B to eccentrically oscillate in phases different from each other. Due to this eccentric oscillation, the meshing position between the external gears 22A and 22B and the internal gear 32 changes along the circumferential direction around the central axis Ax1, and since the number of teeth of the two is different, the external gears 22A and 22B rotate (rotate). And the rotation component of the external gears 22A and 22B is output to the driven member via the output shaft 24.

[0022] [Anti-fouling structure of the crankshaft]

[0023] Figure 2 yes Figure 1 Enlarged view of the R section.

[0024] The crankshaft 21 is provided with a spacer 4 that prevents abrasive powder (dirt, hereinafter referred to as "abrasive powder") generated in the meshing portion or the bearing from entering the eccentric bearing 25, the crankshaft bearings 26 and 27, and the main bearings 28 and 29. The spacer 4 is formed of metal in a substantially annular plate shape and is arranged concentrically with respect to the center axis Ax2 of the crankshaft 21.

[0025] The spacer 4 of the present embodiment includes a first spacer 41 and a second spacer 42 .

[0026] The spacer 4 only needs to be able to prevent the grinding powder from entering at least one of the crankshaft bearings 26 and 27 and the eccentric bearing 25 .

[0027] Here, "hindering the intrusion of milled powder" includes "narrowing of the passage", and "narrowing of the passage" includes a labyrinth structure. Furthermore, "hindering the intrusion of milled powder" includes a structure in which a filter that hinders milled powder is arranged in a portion that narrows the passage (narrowing).

[0028] Furthermore, hereinafter, unless otherwise specified, the “radial direction” refers to a direction perpendicular to the central axis Ax2 of the crankshaft 21 , and the “circumferential direction” refers to a rotation direction centered on the central axis Ax2 of the crankshaft 21 .

[0029] <First spacer>

[0030] The first spacer 41 is disposed between the first external gear 22A and the crankshaft bearing 26 and between the second external gear 22B and the crankshaft bearing 27 .

[0031] The structure of the first spacer 41 disposed on the opposite side of the load between the first external gear 22A and the crankshaft bearing 26 will be described below. The first spacer 41 disposed on the load side between the second external gear 22B and the crankshaft bearing 27 is substantially the same in structure as the first spacer 41 on the opposite side of the load, except that the orientation in the axial direction is opposite, so the description thereof will be omitted.

[0032] like Figure 2 As shown, the first spacer 41 prevents the abrasive powder from entering the eccentric bearing 25, the main bearing 28, and the crankshaft bearing 26. Furthermore, the first spacer 41 restricts the movement of the retainer 25b of the eccentric bearing 25 in the axial direction.

[0033] Specifically, the first spacer 41 includes an inner diameter portion 41 a , a crushed curved portion 41 b , and an outer diameter portion 41 c .

[0034] The inner diameter portion 41 a is formed in a disc shape orthogonal to the axial direction, and the end portion on the inner diameter side is sandwiched in the axial direction by the inner ring 26 b of the crankshaft bearing 26 and the crankshaft 21 (eccentric body 21A).

[0035] In the inner diameter portion 41 a , a plurality of holes 41 d serving as passages for the lubricant are arranged at equal intervals in the circumferential direction.

[0036] Each hole portion 41d overlaps with the adjacent eccentric body bearing 25 in the axial direction (overlaps when viewed from the axial direction). Each hole portion 41d only needs to overlap with the eccentric body bearing 25 in the axial direction at least in part. However, each hole portion 41d is more preferably formed to include a portion that overlaps with the rolling elements 25a of both rows of eccentric body bearings 25 in the axial direction. In other words, each hole portion 41d is more preferably formed to include a portion (radial range) between the maximum inner diameter and the minimum outer diameter of the two rows of eccentric body bearings 25.

[0037] The shape of each hole portion 41d is not particularly limited, and for example Figure 3 As shown in (a) and (b), it can be formed into a circle or a square, such as Figure 3 As shown in (c), it may be formed into a trapezoidal shape or the like in which the width becomes narrower toward the inner diameter side.

[0038] The hole portion 41 d allows the lubricant to flow well between the eccentric bearing 25 and the crankshaft bearing 26 .

[0039] That is, the lubricant is transferred from the load side ( Figure 1 The grease is supplied to the GR portion of the first spacer 41 and sealed inside the device, and is supplied to the eccentric body bearing 25, the crankshaft bearings 26 and 27, and the main bearings 28 and 29. At this time, although the inner diameter portion 41a of the first spacer 41 is arranged between the eccentric body bearing 25 and the crankshaft bearings 26 and 27, a hole portion 41d is formed in the inner diameter portion 41a to overlap the eccentric body bearing 25 in the axial direction. Therefore, the lubricant can flow well in the axial direction through the hole portion 41d.

[0040] Furthermore, the corner portion of the outer diameter side of the load side (eccentric body bearing 25 side) of the inner ring 26b of the crankshaft bearing 26 is cut into a tapered shape to form a notch portion 26e. The notch portion 26e (tapered surface) overlaps the surface (outer peripheral surface) of the eccentric body 21A on which the eccentric body bearing 25 is arranged in the axial direction. Therefore, compared with the case where the inner ring 26b of the crankshaft bearing 26 does not have the notch portion 26e and the end surface on the load side is upright, the lubricant can flow well in the axial direction.

[0041] The flattened curved portion 41b is continuous with the outer diameter end of the inner diameter portion 41a, and is formed by bending from the outer diameter end toward the load side and then folding back to the opposite side of the load. That is, the flattened curved portion 41b includes an extension portion extending in the axial direction. The flattened curved portion 41b is equivalent to an example of the "first obstruction portion" involved in the present invention. The extension portion involved in the present invention can be provided to protrude in the axial direction from the portion extending in the radial direction, and a plurality of extension portions can also be provided.

[0042] The flattened curved portion 41b is opposed to the step portion 221 formed on the side surface opposite to the load side of the first external gear 22A. The step portion 221 of the first external gear 22A is formed so as to be located on the load side in stages as it moves toward the inner diameter side. The portion on the load side of the flattened curved portion 41b overlaps with the step portion 22a in the radial direction (overlaps when viewed from the radial direction) and is thereby opposed to the step portion 22a. Furthermore, the radial position of the flattened curved portion 41b is set so as not to contact the step portion 22a of the first external gear 22A even when the first external gear 22A is most eccentric to the inner diameter side around the center axis Ax1. The step portion 22a is an example of the opposing portion involved in the present invention, and it is sufficient that it is opposed to the extension portion in the radial direction. For example, it may also be an inclined portion that is continuous without a step, and the inclined portion is opposed to the extension portion in the radial direction.

[0043] Thus, a connecting passage having a labyrinth structure is defined between the flattened curved portion 41b and the stepped portion 22a of the first external gear 22A. Here, the labyrinth structure refers to a structure that includes at least a channel portion having an axial direction component and a channel portion having a radial direction component. Furthermore, at least one of these channel portions becomes a narrow portion, and the width of the narrow portion is narrower than the upstream side or the downstream side of the connecting passage, so that a greater resistance acts on the lubricant passing through. The labyrinth structure can effectively prevent the abrasive powder generated in the meshing portion between the first external gear 22A and the internal gear 32 from entering the eccentric body bearing 25.

[0044] The outer diameter portion 41c is continuous with the end portion on the opposite side of the crushed curved portion 41b and is formed in a disk shape perpendicular to the axial direction. The outer diameter portion 41c corresponds to an example of the "second obstruction portion" according to the present invention.

[0045] The axial position of the outer diameter portion 41c corresponds to the retainer 28d of the main bearing 28, and the end portion on the outer diameter side is radially opposed to the retainer 28d, with a narrow portion formed therebetween. This narrow portion can effectively prevent the grinding powder generated in the meshing portion between the first external gear 22A and the internal gear 32 from entering the main bearing 28 or the crankshaft bearing 26.

[0046] Furthermore, the axial position of the outer diameter portion 41c is different from (does not overlap) the axial position of the communication passage 28e that communicates between the inner ring 28b and the retainer 28d of the main bearing 28. Specifically, the outer diameter portion 41c does not protrude further than the flange portion of the retainer 28d in the axial direction. Therefore, the outer diameter portion 41c does not block the communication passage 28e and prevent the lubricant from being supplied to the main bearing 28.

[0047] <Second spacer>

[0048] The second spacer 42 is disposed between the crankshaft bearing 26 and the distributor gear 23 , thereby preventing the abrasive particles from entering the crankshaft bearing 26 .

[0049] Specifically, the second spacer 42 has an inner diameter portion 42 a and a U-shaped portion 42 b .

[0050] The inner diameter portion 42 a is formed in a disc shape orthogonal to the axial direction, and is sandwiched between the inner ring 26 b of the crankshaft bearing 26 and the sleeve 231 in the axial direction.

[0051] More specifically, the U-shaped portion 42b is formed in a shape that bends from the outer diameter end of the inner diameter portion 42a toward the opposite side of the load and then toward the outer diameter side, with the outer diameter end of the U-shaped portion 42b bending toward the load side.

[0052] Thus, the space inside the U-shaped portion 42b functions as a grease chamber P for storing lubricant from the load side (crankshaft bearing 26 side). In the crankshaft bearing 26, which is a tapered roller bearing, grease is more likely to move toward the inner diameter side of the rolling element (roller) 26a (i.e., the opposite side to the load). The U-shaped portion 42b can well receive the lubricant that has moved to the opposite side to the load.

[0053] An end portion on the outer diameter side of the U-shaped portion 42 b is axially opposed to a C-ring 242 that regulates the axial position of the outer ring 26 c of the crankshaft bearing 26 .

[0054] The end of the outer diameter side of the U-shaped portion 42b is radially opposed to the support plate 241 to form a narrow portion therebetween. This narrow portion can effectively prevent the grinding powder generated in the meshing portion of the distribution gear 23 from entering the crankshaft bearing 26 (and further, the eccentric body bearing 25).

[0055] Furthermore, the outer diameter side end of the U-shaped portion 42b forms a labyrinth structure with the support plate 241 and the C-shaped ring 242. This can better prevent the grinding powder from entering the crankshaft bearing 26 (and further entering the eccentric bearing 25).

[0056] [Technical Effects of Implementation Methods]

[0057] As described above, according to the present embodiment, the spacer 4 disposed on the side of the crankshaft bearing 26 prevents abrasive powder (dust) from entering at least one of the crankshaft bearing 26 and the eccentric bearing 25 .

[0058] This can better suppress the intrusion of abrasive powder into at least one of the crankshaft bearing 26 and the eccentric bearing 25 .

[0059] Furthermore, according to the present embodiment, the first spacer 41 disposed between the first external gear 22A and the crankshaft bearing 26 in the spacer 4 has a flattened curved portion 41b (first obstruction portion) that obstructs the entry of abrasive particles into the eccentric bearing 25. The flattened curved portion 41b can suppress the entry of abrasive particles into the eccentric bearing 25.

[0060] The first spacer 41 has an outer diameter portion 41c (second obstruction portion) that cooperates with the retainer 28d of the main bearing 28 to obstruct the entry of grinding powder into the crankshaft bearing 26. The outer diameter portion 41c can suppress the entry of grinding powder into the crankshaft bearing 26.

[0061] Furthermore, according to the present embodiment, the external gear has the step portion 221 which is radially opposed to the extending portion of the crushed curved portion 41 b extending in the axial direction.

[0062] Thus, the crushed curved portion 41 b and the step portion 221 form a labyrinth structure, which can suppress the intrusion of grinding powder into the eccentric bearing 25. In addition, since it is a non-contact labyrinth structure, loss torque can be suppressed.

[0063] According to the present embodiment, the outer diameter portion 41c (second obstruction portion) of the first spacer 41 is radially opposed to the retainer 28d of the main bearing 28 to form a narrow portion. This narrow portion can prevent abrasive particles from entering the main bearing 28 or the crankshaft bearing 26.

[0064] Furthermore, the outer diameter portion 41c (second obstruction portion) does not axially overlap the communication passage 28e that connects the inner ring 28b and the retainer 28d of the main bearing 28. Therefore, the outer diameter portion 41c does not block the communication passage 28e and obstruct the supply of lubricant to the main bearing 28.

[0065] Furthermore, according to the present embodiment, the first spacer 41 has the hole 41 d in the portion overlapping with the eccentric body bearing 25 in the axial direction.

[0066] The hole portion 41 d allows the lubricant to flow favorably in the axial direction between the eccentric bearing 25 and the crankshaft bearing 26 .

[0067] Furthermore, according to the present embodiment, the second spacer 42 disposed between the crankshaft bearing 26 and the distributor gear 23 among the spacers 4 prevents the abrasive powder from entering the crankshaft bearing 26 from the distributor gear 23 side.

[0068] The second spacer 42 can suppress the abrasive particles from entering the crankshaft bearing 26 .

[0069] Furthermore, the crankshaft bearing space can be isolated from the surrounding gears (distributor gear, external gear).

[0070] Furthermore, according to the present embodiment, the second spacer 42 has the U-shaped portion 42 b that opens toward the crankshaft bearing 26 side.

[0071] Thereby, the space inside the U-shaped portion 42 b can be made to function as the grease chamber P.

[0072] [other]

[0073] As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment.

[0074] For example, in the above embodiment, the axial position of the outer diameter portion 41c of the first spacer 41 corresponds to the axial position of the retainer 28d of the main bearing 28. However, the outer diameter portion 41c only needs to have its outermost diameter portion facing the retainer 28d in the radial direction to form a narrow portion.

[0075] For example, Figure 4 As shown in FIG. 1 , the outer diameter portion 41c of the first spacer 41 may be formed in a shape that bends from the end of the flattened curved portion 41b toward the outer diameter side closer to the load side than the retainer 28d of the main bearing 28, then bends toward the opposite load side at the outermost diameter portion and extends to a portion facing the retainer 28d. In this case, the distance between the outer diameter portion 41c of the first spacer 41 and the first external gear 22A can be shortened compared to the above-described embodiment. Furthermore, the intrusion of abrasive powder into the eccentric bearing 25 can be better suppressed.

[0076] Furthermore, the types of bearings of the eccentric bearing, the crankshaft bearing, and the main bearing are not particularly limited.

[0077] Furthermore, the present invention is applicable to any eccentric oscillating gear device in which the crankshaft is arranged at a position offset from the center, and is not particularly limited, and can be widely applied to eccentric oscillating gear devices. For example, it can also be applied to an eccentric oscillating gear device in which a ring gear is meshed with a distribution gear of a plurality of crankshafts and a pinion shaft offset from the center is meshed with the ring gear.

[0078] In addition, the details shown in the above-mentioned embodiment can be appropriately changed within the scope not departing from the gist of the invention.

Claims

1. An eccentric oscillating gear device, comprising: The outer gear is provided with an offset hole at a position offset from the center; a crankshaft inserted into the offset hole and having an eccentric body for causing the external gear to swing; a crankshaft bearing, supporting the crankshaft; and The eccentric bearing is arranged between the external gear and the eccentric body. The eccentric oscillating gear device is characterized in that: A spacer is provided on a side of the crankshaft bearing. The spacer prevents abrasive powder from entering at least one of the crankshaft bearing and the eccentric bearing.

2. The eccentric oscillating gear device according to claim 1, characterized in that: The invention also comprises: a wheel carrier arranged on the side of the external gear; a housing having an internal gear meshing with the external gear; and a main bearing arranged between the wheel carrier and the housing. The spacer includes a first spacer disposed between the external gear and the crankshaft bearing, The first spacer has: A first obstruction portion, which obstructs the grinding powder from entering the eccentric body bearing; and The second blocking portion cooperates with the retainer of the main bearing to block the abrasive particles from entering the crankshaft bearing.

3. The eccentric oscillating gear device according to claim 2, characterized in that: The first spacer has an extending portion extending in the axial direction. The external gear has an opposing portion that is opposed to the extending portion in a radial direction.

4. The eccentric oscillating gear device according to claim 2 or 3, characterized in that: The first spacer has a hole in a portion overlapping with the eccentric body bearing in the axial direction.

5. The eccentric oscillating gear device according to claim 2, characterized in that: The second obstruction portion and the retainer are opposed to each other in the radial direction to form a narrow portion. The second hindering portion does not overlap in the axial direction with a communication passage that connects the inner ring of the main bearing and the retainer.

6. The eccentric oscillating gear device according to claim 1 or 2, characterized in that: The crankshaft has a distribution gear, The spacer includes a second spacer disposed between the crankshaft bearing and the distribution gear, The second spacer prevents the abrasive powder from entering the crankshaft bearing from the distribution gear side.

7. The eccentric oscillating gear device according to claim 6, characterized in that: The second spacer has a concave portion that opens toward the crankshaft bearing side.

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