JP6529863B2 - Eccentric oscillating gear device and industrial robot - Google Patents

Description

  The present invention relates to an eccentric oscillating gear device and an industrial robot incorporating the gear device.

  Patent Document 1 discloses a gear device of an eccentric oscillation type.

  The eccentric rocking gear device includes a casing, a carrier that rotates relative to the casing, a rocking gear, and a crankshaft that rocks and rotates the rocking gear.

  The crankshaft has a hollow portion. A shaft member integrated with the carrier is disposed in the hollow portion. The crankshaft is supported by a pair of bearings disposed between the crankshaft and the shaft member. The bearings are comprised of conical roller bearings.

Patent No. 5122450 (FIG. 4)

  However, in the case of a gear device having a structure as disclosed in Patent Document 1 above, it is difficult to secure a large transmission capacity, particularly with regard to the support of the crankshaft, and in order to secure the necessary transmission capacity, Has a problem of becoming larger.

  The present invention has been made to solve such conventional problems, and it is an object of the present invention to provide an eccentrically oscillating gear device capable of achieving compactness while maintaining a large transmission capacity. The problem is that.

  The present invention relates to an eccentric rocking gear device comprising a casing, a carrier that rotates relative to the casing, a rocking gear, and a crankshaft that rocks and rotates the rocking gear. A hollow portion, and the casing or the carrier has a shaft member inserted into the hollow portion, and the gear unit further includes an outer periphery of the crankshaft and an inner periphery of the casing or the carrier. The above problem is solved by including an outer bearing disposed between the inner and outer bearings, an inner bearing disposed between the inner periphery of the crankshaft, and an outer periphery of the shaft member. .

  In the present invention, the crankshaft has a hollow portion, and the casing or the carrier has a shaft member inserted into the hollow portion. The outer bearing is disposed between the outer periphery of the crankshaft and the inner periphery of the casing or the carrier, and the inner bearing is disposed between the inner periphery of the crankshaft and the outer periphery of the shaft member.

  Thus, the outer bearing can be disposed on the outer periphery of the crankshaft, so a large transmission capacity can be secured. In addition, since the inner bearing can be disposed on the inner periphery of the crankshaft, compactness can be realized.

  According to the present invention, it is possible to obtain an eccentrically oscillating gear device capable of realizing compactness while maintaining a large transmission capacity.

Sectional drawing which shows the gear apparatus of the eccentric oscillation type | mold which concerns on an example of embodiment of this invention Sectional drawing which shows the gear apparatus of the eccentric oscillation type | mold which concerns on other embodiment of this invention. Sectional drawing which shows the gear apparatus of the eccentric oscillation type | mold which concerns on other embodiment of this invention. Principal part sectional view showing an example of an industrial robot incorporating the eccentrically oscillating gear device of FIG. 3 Principal part enlarged sectional view which expands and shows a part of FIG. 4

  Hereinafter, an example of an embodiment of the present invention will be described in detail based on the drawings.

  FIG. 1 is a cross-sectional view showing an eccentrically oscillating gear device G1 according to an example of an embodiment of the present invention.

  The eccentric rocking gear device G1 includes a casing 10, a carrier 20 rotating relative to the casing 10, an external gear (oscillating gear) 30 whose axis is oscillated, and the external gear 30 And a crankshaft 40 that is dynamically rotated.

  The crankshaft 40 of the gear device G1 is formed in a tubular shape, and is disposed with the axis C40 of the internal gear 50 coincident with the axis C50 of the internal gear 50 described later. A tap hole 40T is formed at an axial end 40E of the crankshaft 40. Connected to the crankshaft 40 is a power input member 52 (in this example, a spur gear) for inputting power from a drive source (for example, a motor) to the crankshaft 40. The power input member 52 is connected by screwing a bolt 53 into the tap hole 40T. That is, the crankshaft 40 constitutes an input shaft of the gear device G1.

  The crankshaft 40 is provided with two eccentrics 54 for swinging the external gear 30. The axial center C54 of the eccentric body 54 is eccentric to the axial center C40 of the crankshaft 40. The two eccentric bodies 54 are eccentric with a phase difference of 180 ° to balance the oscillation of the external gear 30. The configuration regarding the support of the crankshaft 40 will be described in detail later.

  An eccentric bearing 56 is disposed between the eccentric 54 and the external gear 30. In the gear device G1, the eccentric bearing 56 is constituted by a roller 56C having no inner ring and no outer ring. The roller 56C is held by a retainer 56R. The external gear 30 is incorporated in the outer periphery of the eccentric body 54 via the roller 56C. Therefore, the axial center C30 of the external gear 30 swings.

The external gear 30, which is a rocking gear, is in mesh with the internal gear 50, which is a non-rocking gear.
The axial center C50 of the internal gear 50 is fixed (does not swing). The internal gear 50 includes an internal gear main body 50A integrated with the casing 10 (a first casing body 11 described later) and a pin groove 50B formed along the axial direction on the inner periphery of the internal gear main body 50A. And a cylindrical internal tooth pin 50C rotatably incorporated in the pin groove 50B and constituting an internal tooth of the internal gear 50. The number of internal teeth of the internal gear 50 (the number of internal tooth pins 50C) is slightly larger (by 1 in this example) than the number of external teeth of the external gear 30.

  A carrier 20 is disposed on the axial direction repulsive power input side of the external gear 30. The carrier 20 is a member that rotates relative to the casing 10. The configuration of the casing 10 and the carrier 20 will be described in detail later.

  A main bearing 60 is disposed between the casing 10 and the carrier 20. The main bearing 60 is a bearing that supports the casing 10 and the carrier 20 so as to be able to rotate relative to each other, and in this gear device G1, it is configured by cross roller bearings. The main bearing 60 comprises a rolling surface 60A on the carrier 20 side corresponding to the inner ring, a rolling surface 60B on the casing 10 side corresponding to the outer ring, and rollers 60C rolling in the rolling surfaces 60A and 60B. ing. Since the main bearings 60 are cross roller bearings, only one can support the carrier 20 in the axial and radial directions.

  On the other hand, a plurality of inner pins 62 pass through the external gear 30 at a position offset from the axial center C30. The external gear 30 is formed with a plurality of inner pin holes 30A through which the inner pin 62 passes. Since the inner pin 62 penetrates the external gear 30, it moves in synchronization with the rotation of the external gear 30. The inner pin 62 integrally protrudes from the carrier 20 in a cantilever manner.

  In the gear device G1, an inner roller 64 is externally fitted to the inner pin 62 as a sliding promoting member. A portion of the inner roller 64 is in contact with the inner pin hole 30 A of the external gear 30. The outer diameter of the inner roller 64 is smaller than the inner diameter of the inner pin hole 30A, and a gap δ30A is secured between the inner roller 64 and the inner pin hole 30A. The swing component of the external gear 30 is absorbed by the gap δ30A secured between the inner roller 64 and the inner pin hole 30A.

  Here, the structure regarding support of the crankshaft 40 is demonstrated.

  Describing the outline, the crankshaft 40 of the gear device G1 has a large diameter hollow portion 40P2. The casing 10 or the carrier 20 (in this example, the carrier 20) integrally has a shaft member 20S inserted into the large diameter hollow portion 40P2. The gear unit G1 includes an outer bearing 72 disposed between the outer periphery 40A of the crankshaft 40 and the inner periphery 20R2 of the casing 10 or the carrier 20 (in this example, the carrier 20). The gear device G1 further includes an inner bearing 74 disposed between the inner periphery (large diameter hollow portion 40P2) of the crankshaft 40 and the outer periphery 20S1 of the shaft member 20S.

  A more detailed description will be given below.

  As described above, the crankshaft 40 of the present gear device G1 is generally formed in a tubular shape. However, the outer diameter and the inner diameter of the crankshaft 40 are not constant.

  The crankshaft 40 has a small diameter hollow portion 40P1 having a small hollow diameter D40P1 and a large diameter hollow portion 40P2 having a hollow diameter D40P2 larger than the hollow diameter D40P1 of the small diameter hollow portion 40P1.

  The small diameter hollow portion 40P1 is formed on the axial direction counterpower input side of the crankshaft 40. The large diameter hollow portion 40P2 is formed on the axial power input side of the crankshaft 40. The small diameter hollow portion 40P1 and the large diameter hollow portion 40P2 are both formed parallel to the axial center C40 of the crankshaft 40.

  The casing 10 of the present gear device G1 includes a first casing body 11 integrated with the internal gear main body 50A, and a second casing body 12 disposed on the axial opposite side of the first casing body 11; The third casing body 13 is disposed on the axial power input side of the first casing body 11.

  The first casing body 11 is located radially outward of the external gear 30, and also serves as the internal gear main body 50A of the internal gear 50, as described above. The second casing body 12 is formed in a ring shape, and a rolling contact surface 60B of the main bearing 60 is formed on the inner periphery thereof. The third casing body 13 is formed of a substantially disc-like member having an opening 13A at the center in the radial direction, and covers the axial power input side of the gear device G1.

  A connecting tap hole 11T is formed through the first casing body 11. The first casing body 11 and the second casing body 12 are connected by screwing the bolt 15 inserted from the second casing body 12 side into the connection tap hole 11T of the first casing body 11. The first casing body 11 and the third casing body 13 are connected by screwing a bolt (not shown) inserted from the third casing body 13 side into the connection tap hole 11T of the first casing body 11 . An O-ring 70 is disposed between the first casing body 11 and the second casing body 12. An O-ring 71 is disposed between the first casing body 11 and the third casing body 13. An oil seal 17 is disposed between the second casing body 12 and the carrier 20.

  The casing 10 seals the inside of the gear device G <b> 1 on the radially outer side of the crankshaft 40 with such a configuration. A lubricant is enclosed in the gear device G1.

  The carrier 20 of the present gear device G1 has a disk-shaped flange portion 20F, a ring portion 20R integrally formed on the outer peripheral portion of the flange portion 20F in the axial direction external gear 30, and a flange portion 20F. Shaft member 20S integrally formed on the side of the external gear 30 in the axial direction C20F (= axial center C20R of the ring portion 20R = axial center C40 of the crankshaft 40 = axial center C50 of the internal gear 50) And a plurality of inner pins 62 integrally formed on the axially external gear 30 side at positions offset from the axial center C20F of the flange portion 20F.

  An outer peripheral surface 20R1 of the ring portion 20R of the carrier 20 is radially opposed to the inner periphery of the second casing body 12. A rolling surface 60A on the carrier 20 side of the main bearing 60 is formed on an outer peripheral surface 20R1 of the ring portion 20R.

  The shaft member 20S of the carrier 20 is inserted into the large diameter hollow portion 40P2 of the crankshaft 40. The outer periphery 20S1 of the shaft member 20S is opposed to the large diameter hollow portion 40P2. In addition, the code | symbol 20T is a tap hole for connecting the other member (driven member) which is not shown in figure.

  In the gear unit G1 having the crankshaft 40, the casing 10, and the carrier 20 having such a configuration, the outer bearing 72 of the main gear unit G1 includes the outer periphery 40A of the end of the crankshaft 40 in the axial direction and the carrier and the carrier. 20 (the ring portion 20R) is disposed between the inner circumference 20R2.

  The outer bearing 72 is configured by a ball bearing having an inner ring 72A, an outer ring 72B, and rolling elements 72C. The positioning of the outer bearing 72 in the axial direction on the reaction power input side is performed by the abutment of the outer ring 72B of the outer bearing 72 and the flange portion 20F (described later) of the carrier 20. Positioning on the axial power input side of the outer bearing 72 is performed by a shoulder 40W1 formed adjacent to the eccentric body 54 via the pressing plate 57 of the retainer 56R of the eccentric bearing 56.

  On the other hand, the inner bearing 74 of the present gear device G1 is a shaft member integrated with the large diameter hollow portion 40P2 of the crankshaft 40, that is, the inner periphery of the end on the axial power input side of the crankshaft 40 and the carrier 20. It is disposed between the outer circumference 20S1 of 20S.

  The inner bearing 74 is composed of a self-aligning roller bearing having an inner ring 74A, an outer ring 74B and two sets of roller rows 74C. At the boundary between the small diameter hollow portion 40P1 and the large diameter hollow portion 40P2 of the crankshaft 40, a wall surface 40W2 formed of a plane perpendicular to the axis is formed in a ring shape. The wall surface 40W2 constitutes a positioning surface on the axial direction counterpower input side of the inner bearing 74. The positioning on the axial power input side of the inner bearing 74 is performed by a snap ring 75 fitted in the shaft member 20S.

  In the present gear device G1, the eccentric body bearing 56 disposed between the external gear (oscillating gear) 30 and the crankshaft 40 does not overlap the inner bearing 74 as viewed in the radial direction. The inner bearing 74 is located closer to the axial power input side (the opposite carrier side) than the eccentric bearing 56.

  Specifically, in the present gear device G1, the shaft member 20S extends from one axial direction side (opposite power input side) of the external gear 30 to the other side (power input side). The inner bearing 74 is disposed at a portion where the shaft member 20S extends beyond the external gear 30 in the axial direction.

  More specifically, the shaft member 20S extends from one axial direction side (opposite power input side) of the casing 10 of the gear device G1 to the other side (power input side). That is, the shaft member 20S extends beyond the axial end face 13E of the casing 10 of the gear device G1 to the outside of the gear device G1. The inner bearing 74 is disposed at a portion where the shaft member 20S extends to the outside of the gear device G1.

  Further, as described above, in the present gear device G1, the power input member 52 (a member to which the power from the drive source is input) is connected to the end 40E of the crankshaft 40 on the power input side. The inner bearing 74 overlaps the power input member 52 as viewed in the radial direction. In the present embodiment, the entire inner bearing 74 is disposed inside the large diameter hollow portion 40P2. However, a part of the inner bearing 74 may be disposed on the inner periphery of the power input member 52. That is, the inner bearing 74 may be disposed across the inner periphery of the large diameter hollow portion 40P2 and the inner periphery of the power input member 52.

  Further, in the present gear device G <b> 1, a main bearing 60 for supporting the casing 10 and the carrier 20 in a relatively rotatable manner is disposed between the casing 10 and the carrier 20. The main bearing 60 overlaps the outer bearing 72 as viewed in the radial direction. That is, in the gear device G1, the main bearing 60 and the outer bearing 72 are located on substantially the same plane Pc.

  As already mentioned, in the present gear device G1, the shaft member 20S is integrated with the carrier 20 (not the casing 10). Further, the outer bearing 72 is disposed between the outer periphery 40A of the crankshaft 40 and the inner periphery 20R2 of the carrier 20 (rather than the inner periphery of the casing 10).

  Further, in the present gear device G1, the outer bearing 72 is disposed closer to the axial reaction force input side than the inner bearing 74.

  Next, the operation of the eccentrically oscillating gear device G1 according to the present embodiment will be described.

  First, the operation of the power transmission system of the eccentrically oscillating gear device G1 will be described. A power input member 52 is connected to an axial end 40E of the crankshaft 40 (input shaft) via a tap hole 40T and a bolt 53. The crankshaft 40 receives power from the drive source through the power input member 52 and rotates. When the crankshaft 40 rotates, the eccentric body 54 integrally formed with the crankshaft 40 rotates.

  When the eccentric body 54 rotates, the axial center C30 of the external gear 30 incorporated in the outer periphery of the eccentric body 54 via the eccentric bearing 56 swings. The external gear 30 internally meshes with the internal gear 50.

  The number of external teeth of the external gear 30 is smaller by one than the number of internal teeth of the internal gear 50 (the number of internal tooth pins 50C). As a result, the external gear 30 is rotated by one rotation of the axial center C 30 each time the crankshaft 40 rotates once, and the number of teeth difference (one tooth) with respect to the meshing internal gear 50. It is out of phase and rotates. The rotation component is transmitted to the inner roller 64 and the inner pin 62 penetrating the external gear 30, and the inner pin 62 revolves around the axial center C50 of the internal gear 50.

  By the revolution of the inner pin 62, the carrier 20 with which the inner pin 62 is integrated rotates (rotations) around the axial center C50 of the internal gear 50. The rotation of the carrier 20 drives the mating member (driven member) coupled to the carrier 20 by utilizing the tap holes 20T.

  Here, in the gear unit G1 according to the present embodiment, the crankshaft 40 has a hollow portion (large diameter hollow portion 40P2), and the casing 10 or the carrier 20 (in this example, the carrier 20) is a large diameter hollow. It integrally has a shaft member 20S to be inserted into the portion 40P2. The outer bearing 72 is disposed between the outer periphery 40A of the crankshaft 40 and the inner periphery 20R2 of the carrier 20, and between the inner periphery (large diameter hollow portion 40P2) of the crankshaft 40 and the outer periphery 20S1 of the shaft member 20S. An inner bearing 74 is arranged.

  Therefore, since the outer bearing 72 can be disposed on the “outer periphery” of the crankshaft 40, the outer diameter of the outer bearing 72 can be set large. For example, in the present gear device G1, the inner diameter D72A of the inner ring 72A of the outer bearing 72 is larger than the outer diameter d74B of the outer ring 74B of the inner bearing 74. That is, the outer bearing 72 has a larger diameter as the whole is positioned radially outward of the inner bearing 74. As a result, a large transmission capacity can be secured, and the support rigidity of the crankshaft 40 can be maintained high.

  In the present embodiment, the outer bearing 72 is formed of a ball bearing by utilizing this merit. As a result, it is possible to configure the gear unit G1 with lower power loss and lower cost (compared to the case where, for example, a bearing having roller-based rolling elements is adopted as the bearing of the crankshaft 40). Since the power loss tends to increase as the diameter of the bearing increases, it is advantageous to be able to configure the bearing of the crankshaft 40 as a ball bearing.

  However, in the present invention, the outer diameter or inner diameter of the outer bearing 72 and the outer diameter or inner diameter of the inner bearing 74 are not particularly limited (the outer bearing 72 needs to be larger than the inner bearing 74). Absent). For example, the inner diameter of the hollow portion (in the above example, the large diameter hollow portion 40P2) in which the inner bearing of the crankshaft is disposed is the outside of the outer periphery (in the above example, the outer periphery 40A of the counteracting input side) in which the outer bearing is disposed. For example, the outer diameter of the outer bearing may be set to be smaller than the outer diameter of the inner bearing by enlarging the diameter so as to be much larger than the diameter.

  Here, the inner bearing 74 of the present embodiment is disposed on the “inner periphery” of the crankshaft 40 and supports the crankshaft 40 from the inside in the radial direction. For this reason, the crankshaft 40 is designed at an arbitrary axial position of the crankshaft 40 in design without depending on the arrangement position of the members (the external gear 30, the power input member 52, etc.) incorporated into the crankshaft 40. Can support. Therefore, compactness (especially, axial compactness) can be realized, and a more flexible design can be realized.

  Specifically, for example, in the gear device G1, in consideration of the fact that the power input member 52 is connected to the axial end 40E of the crankshaft 40, the shaft member 20S is used as the external gear 30 An inner bearing 74 is disposed in a portion extending from one axial side (repulsive power input side) to the other side (power input side), and the shaft member 20S is extended beyond the external gear 30 in the axial direction There is. As a result, the inner bearing 74 overlaps the power input member 52 as viewed in the radial direction, and accordingly, the axial compactness of the entire device can be realized. Also, the power input member 52 can be stably supported.

  On the other hand, in the present gear device G1, the inner bearing 74 is disposed so as not to overlap with the eccentric body bearing 56 (the bearing disposed between the swing gear and the crankshaft) as viewed in the radial direction. There is. Thereby, when the inner bearing 74 is press-fit into the large diameter hollow portion 40P2, the deformation of the crankshaft 40 due to the press-fit is prevented from adversely affecting the eccentric bearing 56.

  Since the outer bearing 72 is originally disposed on the carrier 20 having a large thickness in the axial direction, the axial compactness is not impaired even if disposed on the outer side of the crankshaft 40, By arranging the large diameter outer bearing 72, the transmission capacity can be increased.

  Further, in the present gear device G1, the main bearing 60 for supporting the casing 10 and the carrier 20 in a relatively rotatable manner is disposed between the casing 10 and the carrier 20, and the main bearing 60 and the outer bearing 72 have diameters. Seeing from the direction is overlapping. That is, the main bearing 60 and the outer bearing 72 are located on substantially the same plane Pc. As a result, the axial direction of the gear device G1 can be made compact, the support rigidity around the plane Pc can be maintained high, and the rotational stability of each member can be improved.

  Further, in the present gear device G1, the crankshaft 40 has a small diameter hollow portion 40P1 having a small hollow diameter D40P1 and a large diameter hollow portion 40P2 having a hollow diameter D40P2 larger than the hollow diameter D40P1 of the small diameter hollow portion 40P1. doing. The inner bearing 74 is disposed in the large diameter hollow portion 40P2.

  Thus, the outer diameter d74B of the outer ring 74B of the inner bearing 74 can be made larger, and the transmission capacity of the inner bearing 74 can be secured larger. Further, the wall surface 40W2 formed at the boundary between the small diameter hollow portion 40P1 and the large diameter hollow portion 40P2 can be utilized as a positioning surface on the reaction force input side of the inner bearing 74, and the arrangement of positioning members such as retaining rings is omitted. can do.

  In the present embodiment, the outer bearing 72 is disposed at the end of the crankshaft 40 on the side of the carrier 20, and the inner bearing 74 is disposed at the end of the crankshaft 40 on the side opposite to the carrier 20. However, in the present invention, the position of the outer bearing 72 and the inner bearing 74 in the axial direction of the crankshaft 40 is not particularly limited. For example, the outer bearing 72 may be disposed at the end on the side opposite to the carrier 20 of the crankshaft 40, or in the vicinity of the axial center of the crankshaft 40 as in the embodiment described later. May be The same applies to the inner bearing 74, and the axial arrangement position is not particularly limited. When at least one of the outer bearing 72 and the inner bearing 74 is configured by a single bearing such as a spherical roller bearing or a cross roller bearing that can support the crankshaft 40 in the thrust and radial directions. Alternatively, the outer bearing 72 and the inner bearing 74 may be arranged so as to overlap in the radial direction.

  FIG. 2 shows a configuration example of an eccentrically oscillating gear device G101 according to another embodiment of the present invention.

  The parts common to the embodiment in FIG. 1 technically or the corresponding parts are denoted by the same reference numerals in the lower two digits, and the repeated description will be appropriately omitted.

  Also in the eccentrically oscillating gear device G101, the crankshaft 140 has a hollow portion (small diameter hollow portion 140P1 and large diameter hollow portion 140P2). The casing 110 or the carrier 120 integrally has a shaft member 110S inserted into the large diameter hollow portion 140P2. In this example, unlike the previous example, the casing 110 (specifically, a third casing body 113 described later) integrally includes the shaft member 110S.

  As in the example of FIG. 2 and the example of FIG. 3 to be described next, for example, in the case where the shaft member does not penetrate the small diameter hollow portion, the hollow diameter of the small diameter hollow portion is 0 Good. That is, it may be a structure in which there is virtually no small diameter hollow portion (the portion corresponding to the small diameter hollow portion is solid) and only a large diameter hollow portion with a bottom.

  The gear unit G101 includes an outer bearing 172 disposed between the outer periphery 140A of the crankshaft 140 and the inner periphery 120R2 of the casing 110 or the carrier 120 (in this example, the carrier 120). In addition, the gear device G101 includes an inner bearing 174 disposed between the inner periphery (large diameter hollow portion 140P2) of the crankshaft 140 and the outer periphery 110S1 of the shaft member 110S.

  The crankshaft 140 of this gear train G101 has a tap hole 140T for connecting a power input member (not shown) to the end 140E on the side where the carrier 120 is disposed (as opposed to the previous example) There is. That is, the side on which the carrier 120 is disposed is the power input side.

  In other words, in the gear device G101, the outer bearing 172 is disposed on the axial power input side more than the inner bearing 174, contrary to the previous gear device G1.

  The casing 110 of the gear device G101 includes a first casing body 111 integrated with the internal gear body 150A, a second casing body 112 disposed on the carrier 120 side of the first casing body 111, and a first casing body. The third casing body 113 is disposed on the side opposite to the carrier 120 of 111.

  The configurations of the first and second casing bodies 111 and 112 are the same as in the embodiment of FIG. However, the third casing body 113 is formed of a disk-shaped member without an opening. The third casing body 113 integrally has a shaft member 110S inserted in the large diameter hollow portion 140P2 of the crankshaft 140 at the center in the radial direction. The shaft member 110S protrudes from the third casing body 113 by an axial length substantially corresponding to the axial width of the inner bearing 174.

  Thus, the shaft member may be integrated with the carrier as in the previous embodiment, or may be integrated with the casing as in the present embodiment. In addition, as in the two embodiments described above, the configuration may be integrated with the casing and the carrier from the beginning, or a single shaft member may be connected to the casing and the carrier by bolts or press-fits, etc. It is also good.

  In addition, the radial direction center part of the 3rd casing body 113 is shifted only by (delta) 113 to the anti-carrier 120 side (anti-power input side). With this configuration, the third casing body 113 functions as a pressing plate for the internal tooth pin 150C and the inner roller 164 in the radially outer portion of the third casing body 113. Further, in the radial direction central portion of the third casing body 113, a space for forming the protrusion 140H on the crankshaft 140 is secured. The projection 140H positions the retainer 156R of the eccentric bearing 156.

  The carrier 120 of the gear device G101 is formed so as to protrude toward the axially external gear 130 side at a ring portion 120R arranged to face the second casing body 112 and a position offset from the axial center C120R of the ring portion 120R. And a plurality of inner pins 162. That is, since the carrier 120 of the gear device G101 does not have to have a disk-like flange portion for causing the shaft member to protrude, it does not have the flange portion that was present in the gear device G1 of FIG. Instead, an opening 120R5 is formed in the ring portion 120R of the carrier 120, and the opening 120R5 is used to input power from the drive source side.

  Gear device G101 includes crankshaft 140, casing 110, and carrier 120 having such a configuration, and between the outer periphery 140A of the center of crankshaft 140 substantially in the axial direction and the inner periphery of (the ring portion 120R of) carrier 120. An outer bearing 172 is arranged. In addition, an inner bearing 174 is provided between the inner periphery (large diameter hollow portion 140P2) of the end on the axial direction counterpower input side of the crankshaft 140 and the outer periphery 110S1 of the shaft member 110S (integrated with the casing 110). It is arranged.

  In the gear unit G101 of FIG. 2, the positioning of the outer bearing 172 on the axial power input side is provided with the outer ring of the outer bearing 172 on the ring portion 120R of the carrier 120 (because the carrier 120 does not have a flange portion). This is done by contacting the shoulder 120R3.

  The large diameter hollow portion 140P2 of the crankshaft 140 of the present gear device G101 overlaps with the eccentric bearing 156 when viewed from the radial direction. That is, in the present gear device G101, the eccentric body bearing 156 and the inner bearing 174 overlap as viewed in the radial direction. Thereby, the protrusion amount of the crankshaft 140 on the side opposite to the carrier 120 from the eccentric body 154 is suppressed, and the axial direction of the gear device G101 is made compact.

  FIG. 3 shows a configuration example of an eccentrically oscillating gear device G201 according to still another embodiment of the present invention.

  The gear unit G201 of FIG. 3 basically has the same configuration as the gear unit G101 of FIG. Therefore, the lower two digits are assigned the same reference numerals in the parts that are technically common to the embodiment of FIG. 2 or the corresponding parts.

  A major feature of this gear train G201 is that the main bearing 260 for rotatably supporting the casing 210 and the carrier 220 is not disposed between the casing 210 and the carrier 220. That is, in this gear device G201, the main bearing 260 is not disposed between the casing 210 and the carrier 220 of the gear device G201 on the premise that the gear device G201 is incorporated into the joint of the industrial robot, It is arranged between the first joint member 981 and the second joint member 982 which are components of the robot R901.

  This configuration will be described in more detail with reference to FIGS. 4 and 5.

  FIG. 4 shows an example of an industrial robot R901 in which the gear device G201 of FIG. 3 is incorporated in the indirect part of the fifth stage. For convenience, the gear unit G201 of FIG. 3 is hereinafter referred to as a fifth gear unit. The industrial robot R901 is a welding robot called a spot gun having six degrees of freedom.

  A bevel gear 952 as a power input member is connected to an axial end 240E of the crankshaft 240, which is an input shaft of the fifth gear unit G201, by utilizing the tap hole 240T. The power from the motor (not shown) is input to the bevel gear 952 through the bevel pinion 954.

  The carrier 220 of the fifth gear unit G201 is connected to the first joint member 981 of the industrial robot R901 via a bolt 984. In this example, the first joint member 981 is an output member of a gear device (fourth gear device) G401 incorporated in a joint portion of a front stage (fourth gear).

  The casing 210 of the fifth gear unit G201 is connected to the second joint member 982 of the industrial robot R901 via a bolt 985. In this example, the second joint member 982 connects the casing 210 of the fifth gear device G201 and the casing 610 of the gear device (sixth gear device) G601 incorporated in the joint portion of the rear stage (sixth stage). It is a joint casing.

  In other words, the fifth stage gear train G201 of the industrial robot shown in FIG. 3 is connected to the first joint member 981 (which is the output member of the previous stage) connected to the carrier 220 and the casing 210. It can be understood that the second joint member 982 (which is the rear casing 210) is attached.

  In the fifth gear unit G201, the main bearing 260 supporting the casing 210 and the carrier 220 so as to be relatively rotatable is not disposed between the casing 210 and the carrier 220, and the first joint member 981 and the second joint It is disposed between the member 982. The main bearing 260 is, in this embodiment, a cross roller bearing.

  More specifically, as shown in FIG. 4, the first joint member 981 has its rotation center line (the rotation center line of the output member of the fourth gear device G 401 incorporated in the front joint) C 981 It extends substantially coaxially and reaches near the crankshaft 240 of the fifth gear unit G201.

  The first joint member 981 is connected to the carrier 220 of the fifth gear unit G201 via a bolt 984 on one side of the rotation center line C981 across the rotation center line C981 of the first joint member 981. . The first joint member 981 has a pipe shaft portion 981S coaxially with the axial center C240 of the crankshaft 240 of the fifth gear device G201 on the other side of the rotation center line C981.

  On the other hand, the second joint member 982 is constituted by a substantially cylindrical member. The second joint member 982 has an outer fitting portion 982R surrounding the pipe shaft portion 981S from the outside at the cylindrical end 982E.

  The main bearing 260 of the fifth gear unit G201 is disposed between the pipe shaft portion 981S of the first joint member 981 and the outer fitting portion 982R of the second joint member 982.

  That is, the fifth gear unit G201 is disposed on one side of the rotation center line C981 across the rotation center line C981 of the first joint member 981, and the main bearing 260 of the fifth gear unit G201 is disposed on the other side. It is done. With such a configuration, the carrier 220 and the casing 210 of the fifth gear unit G201 are supported so as to be relatively rotatable by the main bearing 260, thereby, in particular, particularly for the fifth gear unit G201 of the rotation center line C981. The axial dimension LG201 on the gear mechanism side (the side on which the crankshaft 240 and the external gear 230 are present) is made compact.

  The “rotation center line” of the configuration “the fifth gear unit G201 is disposed on one side of the rotation center line C981 and the main bearing 260 of the fifth gear unit G201 is disposed on the other side”. The rotation center line C622 of the output member (second carrier 622 described later) of the sixth gear device G601 incorporated in the “joint portion of the second stage (sixth stage)” of the joint portion can also be grasped. That is, the industrial robot R901 is regarded as "the fifth gear unit G201 is disposed on one side of the rotation center line C 622 and the main bearing 260 of the fifth gear unit G201 is disposed on the other side". It can also be done.

  Furthermore, in the industrial robot R901, “the fifth gear unit G201 is disposed on one side of the plane P901 across the plane P901 including the rotation center line C981 and the rotation center line C622, and the fifth The main bearing 260 of the step gear device G201 is disposed. "

  Finally, the configuration of the second stage gear unit G201 of the industrial robot R901 will be briefly described.

  As described mainly with reference to FIG. 5, the sixth gear gear G <b> 601 subsequent to the fifth gear gear G <b> 201 includes a dedicated motor 605. A motor shaft 605A of the motor 605 is connected to a crankshaft 640 via pulleys 608 and 609. An external gear 630 is incorporated in the crank shaft 640 so as to be capable of oscillating and rotating via an eccentric body 654 and an eccentric body bearing 656. The external gear 630 is internally meshed with the internal gear 650. The number of internal teeth of the internal gear 650 is slightly (for example, 1) larger than the number of external teeth of the external gear 630. First and second carriers 621 and 622 are disposed on both axial sides of the external gear 630. The first and second carriers 621 and 622 are rotatably supported by the casing 610 via main bearings 660A and 660B.

  As described above, the casing 610 of the sixth gear device G601 is connected to the casing 210 of the fifth gear device G201 via the second joint member 982. The external gear 630 has a plurality of inner pins 662 penetrating therethrough at a position offset from the axial center thereof. Since the inner pin 662 passes through the external gear 630, it moves in synchronization with the rotation of the external gear 630. The inner pin 662 is supported by the first and second carriers 621 and 622.

  The inner pin 662 is fitted into the first carrier 621 by clearance fitting. The inner pin 662 is press-fit into the second carrier 622 by an interference fit. An inner roller 664 is externally fitted to the inner pin 662 as a slide promoting member.

  Between the inner pin 662 and the inner roller 664, two rows of first and second needle bearings 691, 692 are arranged in line in the axial direction. The first and second needle bearings 691 and 692 are held via first and second retainers 691R and 692R, respectively. The first and second needle bearings 691 and 692 are axially positioned by being pinched by the first and second carriers 621 and 622 with the first and second retainers 691R and 692R in axial contact. ing.

  When the first and second needle bearings 691 and 692 are thus arranged between the inner pin 662 and the inner roller 664, relative rotation between the inner pin 662 and the inner roller 664 is extremely smoothly performed. Even if an unexpected load is transmitted from the side of the spot gun apparatus 988, the influence thereof can be minimized, and as a result, the external gear 630 can be smoothly rocked and rotated.

  In addition, since the two first and second needle bearings 691 and 692 are incorporated in parallel, the first and second needle bearings 691 and 692 are compared with a configuration in which one long needle bearing is incorporated. 692 will be able to rotate individually in slightly different ways. This makes it possible to better absorb the load from the side of the spot gun apparatus 988.

  The revolution of the inner pin 662 and the inner roller 664 causes the first and second carriers 621 and 622 to rotate. An attachment 989 provided with a spot gun device 988 is connected to the second carrier 622 via an adapter 983 connected by bolts 986. In the sixth gear unit G601, when the motor shaft 605A of the motor 605 rotates, the first and second carriers 621 and 622 relatively rotate with respect to the casing 610 connected to the second joint member 982, The entire attachment 989 connected to the second carrier 622 rotates around a rotation center line C 622 of the second carrier 622, which is an output member of the sixth gear unit G601.

  In the above embodiment, a) the outer bearing is disposed between the outer periphery of the crankshaft and the inner periphery of the carrier, and the inner bearing is the inner periphery of the crankshaft and the outer periphery of the shaft member integrated with the carrier. A configuration in which the outer bearing is disposed between the outer periphery of the crankshaft and the inner periphery of the carrier, and the inner bearing is integrated with the inner periphery of the crankshaft and the casing A configuration (the configuration of FIGS. 2 and 3) disposed between the outer periphery of the member was shown.

  However, the present invention is not limited to this configuration example. For example, c) the outer bearing is disposed between the outer periphery of the crankshaft and the inner periphery of the casing, and the inner bearing is integral with the inner periphery of the crankshaft and the carrier. A configuration disposed between the outer periphery of the fixed shaft member or d) an outer bearing is disposed between the outer periphery of the crankshaft and the inner periphery of the casing, and the inner bearing is disposed on the inner periphery of the crankshaft and the casing You may employ | adopt the structure arrange | positioned between the outer periphery of the integrated shaft member.

  In addition, as this type of eccentrically oscillating gear device, those having various casing structures and carrier structures are conventionally known. That is, in each of the above embodiments, the configuration example in which the carrier is disposed only on one side in the axial direction of the oscillating gear is shown, but as the eccentric oscillating type gear device, for example, the sixth stage It is also known to have the carrier on both axial sides of the oscillating gear, as has been adopted in gearing. Further, in the above embodiment, an eccentrically oscillating gear device called a so-called center crank type in which only one crankshaft is provided on the axial center of the non-oscillating gear (in the above example, the internal gear) It was shown. However, as an eccentric rocking type gear device, for example, so-called distribution type in which a plurality of crankshafts having an eccentric body for rocking the rocking gear are provided at a plurality of positions offset from the axis of the non rocking gear. The known eccentrically oscillating gearing is also known. Furthermore, in the said embodiment, the structural example in which the rocking gear was comprised by the external gear, and the non-rocking gear was comprised by the internal gear was shown. However, as a gear device of an eccentric rocking type, for example, a gear device in which this relationship is reversed, the external gear is a non-rocking gear, and the internal gear is a rocking gear is also known. It is. The present invention is applicable to an eccentrically oscillating gear device of any configuration.

  When this type of eccentric rocking gear device is incorporated into, for example, a joint of an industrial robot, as exemplified in the above-described embodiment, the gear device is mounted in relation to the arrangement of the front and rear joint members and the motor, etc. In contrast, it is necessary to input and output power from various directions. In addition, it is required to realize high compactness while maintaining high transmission capacity or high support rigidity.

  For this reason, the design of the gear apparatus with various casing structures and carrier structures is calculated | required according to those requirements. On the other hand, in this type of eccentric rocking gear device, as exemplified in the above embodiment, for example, there is a carrier on only one side in the axial direction of the crankshaft, or power on only one side. There are many cases where the input member is present, and in many cases, there is a "difference" in the radial allowance between the axial power input side and the counterpower input side of the crankshaft. In the present invention, since the outer bearing is provided on the outer periphery of the crankshaft and the inner bearing is provided on the inner periphery of the crankshaft, flexibility with respect to this “difference” in the radial margin is extremely high. It is possible to design a dynamic gear system and is widely applicable to various industrial robots.

G1 Gear device 10 Casing 20 Carrier 20S Shaft member 30 External gear (oscillation gear)
40 Crankshaft 40P2 (large diameter) hollow portion 72 Outer bearing 74 inner bearing

Claims (10)

An eccentric rocking gear device comprising a casing, a carrier rotating relative to the casing, a rocking gear, and a crankshaft rotating the rocking gear.
The crankshaft has a hollow portion,
The casing or the carrier has a shaft member inserted into the hollow portion,
The gear unit further comprises:
An outer bearing disposed between the outer periphery of the crankshaft and the inner periphery of the casing or the carrier;
And an inner bearing for supporting the crankshaft, which is disposed between an inner periphery of the crankshaft and an outer periphery of the shaft member,
Eccentric rocking type in which only a single outer bearing is disposed as a bearing for supporting the crankshaft between the outer periphery of the crankshaft and the inner periphery of the casing or the carrier Gear device. In claim 1,
An eccentric bearing disposed between the oscillating gear and the crankshaft;
An eccentric rocking gear device characterized in that the eccentric bearing and the inner bearing overlap as viewed in the radial direction. In claim 1,
An eccentric bearing disposed between the oscillating gear and the crankshaft;
An eccentric oscillation gear device characterized in that the eccentric bearing and the inner bearing do not overlap as viewed in the radial direction. In claim 3,
The shaft member extends from one axial direction side of the rocking gear to the other side.
The eccentrically oscillating gear device characterized in that the inner bearing is disposed at a portion where the shaft member extends axially beyond the oscillating gear. In claim 3 or 4,
A power input member connected to an end of the crankshaft and receiving power from a power source;
An eccentric rocking gear device characterized in that the power input member and the inner bearing overlap as viewed in the radial direction. In any one of claims 1 to 5,
A main bearing rotatably supporting the casing and the carrier relative to each other is disposed between the casing and the carrier;
An eccentric rocking gear device characterized in that the main bearing and the outer bearing overlap as viewed in the radial direction. In any one of claims 1 to 6,
The shaft member is integrated with the carrier,
The eccentrically oscillating gear device, wherein the outer bearing is disposed between an outer periphery of the crankshaft and an inner periphery of the carrier. An eccentric rocking gear device comprising a casing, a carrier rotating relative to the casing, a rocking gear, and a crankshaft rotating the rocking gear.
The crankshaft has a hollow portion,
The casing or the carrier has a shaft member inserted into the hollow portion,
The gear unit further comprises:
An outer bearing disposed between the outer periphery of the crankshaft and the inner periphery of the casing or the carrier;
And an inner bearing disposed between the inner periphery of the crankshaft and the outer periphery of the shaft member,
The eccentric rocking gear device, wherein the outer bearing is disposed on the axial power input side with respect to the inner bearing. In any one of claims 1 to 8,
The crankshaft has a small diameter hollow portion having a small hollow diameter including 0, and a large diameter hollow portion having a hollow diameter larger than the hollow diameter of the small diameter hollow portion,
An eccentric rocking gear device characterized in that the inner bearing is disposed in the large diameter hollow portion. Polarized KokoroYurado type gear device is a industrial robot incorporated into the joint,
The gear unit is
An eccentric rocking gear device comprising a casing, a carrier rotating relative to the casing, a rocking gear, and a crankshaft rotating the rocking gear.
The crankshaft has a hollow portion,
The casing or the carrier has a shaft member inserted into the hollow portion,
The gear unit further comprises:
An outer bearing disposed between the outer periphery of the crankshaft and the inner periphery of the casing or the carrier;
And an inner bearing disposed between the inner periphery of the crankshaft and the outer periphery of the shaft member,
The industrial robot is
A first joint member coupled to the carrier;
And a second joint member connected to the casing.
A main bearing that supports the casing and the carrier relatively rotatably is not disposed between the casing and the carrier, but is disposed between the first joint member and the second joint member, and The reduction gear mechanism of the gear unit is disposed on one side of the rotation center line with respect to the rotation center line of an output member of the gear unit incorporated in the front joint portion or the rear joint portion of the joint portion. An industrial robot, wherein the main bearing is disposed.

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