Rotation device

Abstract

To provide a rotation device which ensures improvement of driving efficiency.SOLUTION: A rotation device includes: a cylindrical case 2; a carrier which is rotatably supported by an inner peripheral surface 2b of the case 2 through a first bearing and a second bearing 16 and in which first pin insertion holes and second pin insertion holes 25b are formed along a direction of a rotation axis; power transmission pins 9 each of which is inserted into the pin insertion holes of the carrier and supported by the carrier; pairs of first bush and second bush 72 each of which is fitted with an outer peripheral surface 9a of the power transmission pin 9 and disposed arranged side by side with the first bearing and the second bearing 16 in the direction of the rotation axis; and pairs of first oscillation gear and second oscillation gear 12 each of which engages with the power transmission pin 9 through the first bush and the second bush 72 and transmits rotational force between themselves and the carrier through the power transmission pin 9. An outer end surface 72a of each bush 72 contacts only with the first bearing or the second bearing 16.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rotating device. [Background technology]

[0002] Among rotating devices, there is a transmission that receives rotation from an input section, for example, an electric motor, and outputs the rotation from an output section after slowing or accelerating it. Among transmissions, there is, for example, an eccentric oscillating type reducer that has high rotational position accuracy and high load resistance. This type of reducer includes, for example, a case (frame) with an internal gear formed on its inner circumferential surface, an oscillating gear (external gear) that meshes with the internal gear and oscillates and rotates, a crankshaft (input rotor) that has an eccentric part that rotatably supports the oscillating gear and transmits a rotational force to the oscillating gear, a pin (carrier pin) to which the rotational force of the oscillating gear is transmitted, and a carrier (output rotor) connected to the pin.

[0003] The crankshaft is rotatably supported by the carrier via bearings. The carrier is rotatably supported by the case via bearings. The carrier is also formed with pin insertion holes into which pins are inserted or press-fitted. The oscillating gear is also formed with pin insertion holes into which pins are inserted. By inserting the pins into these pin insertion holes, the rotation of the oscillating gear is transmitted to the carrier via the pins. The pin insertion hole of the oscillating gear is formed to a size that allows the oscillating movement of the oscillating gear relative to the pin. A cylindrical bush is fitted onto the outer circumferential surface of the pin at the location of the pin insertion hole of the oscillating gear. This allows sliding contact between the bush, the pin, and the oscillating gear, minimizing contact resistance and improving drive efficiency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-82993 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned conventional technology, the axial end face of the bush slides against the bearing or carrier, resulting in large contact resistance, which makes it difficult to improve the drive efficiency of the reducer.

[0006] The present invention provides a rotation device capable of reliably improving drive efficiency. [Means for solving the problem]

[0007] A rotating device according to one embodiment of the present invention comprises a cylindrical first member, a second member rotatably supported on an inner surface of the first member via a bearing and having a pin insertion hole formed along the direction of a rotation axis, a pin inserted into the pin insertion hole of the second member and supported by the second member, a bush fitted to the outer surface of the pin and arranged side by side with the bearing in the direction of the rotation axis, and a third member that engages with the pin via the bush and transmits rotational force between the pin and the second member via the pin, and the end face of the bush on the bearing side is in contact only with the bearing.

[0008] This configuration can prevent the bush from coming into contact with the second member in addition to the bearing. As a result, the contact area of ​​the end face of the bush on the bearing side can be made smaller than when the bush contacts the bearing and the second member. As a result, the contact resistance of the bush can be reduced, and the drive efficiency of the rotating device can be reliably improved.

[0009] In the above configuration, the bearing may protrude beyond the end face of the second member facing the bush, and the radial thickness of the bush may be greater than the distance between the outer peripheral surface of the pin and the inner peripheral surface of the bearing.

[0010] In the above configuration, the bearing and the bush may have the same hardness.

[0011] A rotating device according to another aspect of the present invention includes a cylindrical internal gear having internal teeth, a carrier rotatably supported on an inner circumferential surface of the internal gear via a first bearing and having a first pin insertion hole along the direction of a rotation axis, a crankshaft rotatably supported on the carrier via a second bearing and having an eccentric portion, an oscillating gear rotatably supported on the eccentric portion of the crankshaft and having external teeth meshing with the internal teeth and a second pin insertion hole, a pin inserted into the first pin insertion hole and the second pin insertion hole, and a bush fitted into a portion of an outer circumferential surface of the pin that is inserted into the second pin insertion hole, wherein the first bearing and the second bearing are arranged side by side in the radial direction, the first pin insertion hole and the second pin insertion hole are arranged opposite each other in the direction of the rotation axis, the first bearing, the second bearing, and the bush are arranged side by side in the direction of the rotation axis, and an end face of the bush facing the first bearing and the second bearing is in contact with at least one of the first bearing and the second bearing.

[0012] In this way, in a so-called eccentric oscillating type reduction mechanism having a crankshaft and an oscillating gear, the bush can be prevented from contacting the carrier in addition to the first and second bearings. As a result, the contact area of ​​the bush at the end face on the bearing side can be made smaller than when the bush contacts the carrier and each bearing. As a result, the contact resistance of the bush can be reduced, and the drive efficiency of the rotating device can be reliably improved.

[0013] In the above configuration, the first bearing may protrude beyond the end face of the carrier facing the bush, and the radial thickness of the bush may be greater than the distance between the outer peripheral surface of the pin and the inner peripheral surface of the first bearing.

[0014] In the above configuration, the second bearing may protrude from the end face of the carrier facing the bush, and the radial thickness of the bush may be greater than the distance between the outer peripheral surface of the pin and the outer peripheral surface of the second bearing.

[0015] In the above configuration, the first bearing, the second bearing, and the bushing may have the same hardness. Effect of the Invention

[0016] The above-described rotating device can reliably improve the driving efficiency. [Brief description of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view of a reducer according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view of part II in FIG. [Diagram 3] FIG. 11 is a partially enlarged view of a reduction gear according to a modified example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Next, an embodiment of the present invention will be described with reference to the drawings.

[0019] <Reducer> FIG. 1 is a cross-sectional view of a reducer 1. The reducer 1 as a rotating device is a so-called eccentric oscillating type reducer. The reducer 1 includes a cylindrical case (an example of an internal gear and a first member in the claims) 2, and a carrier (an example of a second member in the claims) 7 rotatably supported on the case 2 via two bearings (an example of a bearing and a first bearing in the claims) 15, 16 (first bearing 15, second bearing 16). Hereinafter, the axial direction of the case 2 will be simply referred to as the axial direction. The circumferential direction of the case 2 will be simply referred to as the circumferential direction. The radial direction of the case 2 will be simply referred to as the radial direction. With regard to the axial direction, the axial center side of the case 2 may be referred to as the axial inner side, and the side opposite the axial inner side may be referred to as the axial outer side.

[0020] <Case> The case 2 is made of an iron-based material such as cast iron. Alternatively, the case 2 may be made of an aluminum alloy, a magnesium alloy, a carbon fiber reinforced plastic (CFRP), a resin containing boron nitride to increase thermal conductivity, or the like. A plurality of bolt holes 2a are formed at equal intervals in the circumferential direction on the outer periphery of the case 2, penetrating in the axial direction. The reducer 1 is fixed to the external device by inserting bolts (not shown) into the bolt holes 2a and tightening the bolts to the external device.

[0021] Bearing housings 3, 4 (a first bearing housing 3 and a second bearing housing 4) are formed on both axial sides of the inner circumferential surface 2b of the case 2. The bearing housings 3, 4 are formed so that their inner diameters are larger than the inner diameter of the inner circumferential surface 2b of the case 2 via stepped portions 3a, 4a.

[0022] A seal housing 5 is formed on the inner circumferential surface 2b of the case 2, axially outward of the second bearing housing 4. The seal housing 5 is formed so that its inner diameter is larger than the inner diameter of the second bearing housing 4 via a step portion 5a. A seal 40 is fitted into the seal housing 5. The seal 40 provides a seal between the case 2 and the carrier 7.

[0023] A plurality of internal tooth pins 6 are provided on the inner circumferential surface 2b of the case 2 between the two bearing housings 3, 4. The internal tooth pins 6 are formed in a cylindrical shape extending in the axial direction. However, this is not limited thereto, and the internal tooth pins 6 may be hollow members. The internal tooth pins 6 are arranged at equal intervals in the circumferential direction. The internal tooth pins 6 function as a part of the reduction mechanism 30. That is, the internal tooth pins 6 function as internal teeth that mesh with the oscillating gears 11, 12 described later.

[0024] A first bearing 15 is fitted into the first bearing housing 3 of the case 2 configured in this manner. A second bearing 16 is fitted into the second bearing housing 4. Since the first bearing 15 and the second bearing 16 have the same configuration, only the second bearing 16 will be described below. The first bearing 15 will be denoted by the same reference numerals as the second bearing 16 and will not be described again.

[0025] The second bearing 16 is formed of high carbon chromium bearing steel such as SUJ2. The second bearing 16 is a ball bearing. More specifically, the second bearing 16 is an angular contact ball bearing. The second bearing 16 includes an annular outer ring 17, an annular inner ring 18 disposed radially inside the outer ring 17, and rolling elements 19 disposed between the outer ring 17 and the inner ring 18. The outer ring 17 is fitted into the second bearing housing 4. An end face 17a on the axially inner side of the outer ring 17 abuts against a stepped portion 4a of the second bearing housing 4. This positions the second bearing 16 relative to the case 2.

[0026] <Deceleration mechanism> The reduction gear mechanism 30 includes a carrier 7, a power transmission pin 9 provided on the carrier 7, a crankshaft 8 rotatably supported on the carrier 7 via two bearings (an example of the second bearings in the claims) 33, 34 (third bearing 33, fourth bearing 34), and two oscillating gears (an example of the third member in the claims) 11, 12 (first oscillating gear 11, second oscillating gear 12) rotatably supported on the crankshaft 8. The rotation axis of the carrier 7 and the rotation axis of the crankshaft 8 coincide with each other. These rotation axes coincide with the central axis of the case 2.

[0027] The carrier 7 is composed of a disk-shaped first flange 13 and a second flange 14 arranged on both sides in the axial direction. The first flange 13 and the second flange 14 are made of an iron-based material such as cast iron. Of the two flanges 13, 14, the second flange 14 is disposed on the seal housing 5 side of the case 2. That is, the outer peripheral surface of the second flange 14 is fitted into the inner ring 18 of the second bearing 16. The outer peripheral surface of the first flange 13 is fitted into the inner ring 18 of the first bearing 15.

[0028] The first flange 13 is formed so that its axial thickness is uniform throughout. That is, an outer end surface 13b on the axial outside and an inner end surface 13c on the axial inside of the first flange 13 are each formed flat and arranged parallel to each other. A first opening 13a is formed in the radial center of the first flange 13, penetrating the first flange 13 in the axial direction. A third bearing housing 35 is formed in the first opening 13a. A plurality of first bolt insertion holes 51 are formed in the first flange 13 between the outer circumferential surface and the third bearing housing 35. The first bolt insertion holes 51 penetrate the first flange 13 in the axial direction. The first bolt insertion holes 51 are arranged at equal intervals in the circumferential direction.

[0029] The second flange 14 is formed so that its thickness in the axial direction is uniform throughout. That is, an outer end surface 14d on the axial outside and an inner end surface 14e on the axial inside of the second flange 14 are each formed flat and disposed parallel to each other. A part of the outer peripheral surface of the second flange 14 faces the seal housing 5 of the case 2 in the radial direction. A seal 40 is fitted into this facing portion. This provides a seal between the case 2 and the second flange 14 of the carrier 7.

[0030] An outer peripheral bearing housing 14a is formed on the axially inner side of the outer peripheral surface of the second flange 14. The outer peripheral bearing housing 14a is formed so that the outer diameter is smaller than the outer diameter of the second flange 14 via a step portion 14b. An inner ring 18 of the second bearing 16 is fitted into the outer peripheral bearing housing 14a. An outer end surface 18a on the axially outer side of the inner ring 18 abuts against the step portion 14b. This positions the second bearing 16 relative to the second flange 14.

[0031] A second opening 14c is formed in the radial center of the second flange 14, penetrating the second flange 14 in the axial direction. A fourth bearing housing 36 is formed on the axially inner side of the inner circumferential surface of the second opening 14c. The fourth bearing housing 36 is formed so that its inner diameter is larger than the inner diameter of the second opening 14c via a step portion 36a. The fourth bearing housing 36 is aligned radially with the outer circumferential bearing housing 14a and the second bearing housing 4.

[0032] A plurality of second bolt insertion holes 52 are formed in the second flange 14 between the outer peripheral bearing housing 14a and the fourth bearing housing 36. The second bolt insertion holes 52 penetrate the second flange 14 in the axial direction. The second bolt insertion holes 52 are arranged at equal intervals in the circumferential direction and coaxially with the first bolt insertion holes 51. The inner diameter of the second bolt insertion holes 52 is the same as the inner diameter of the first bolt insertion holes 51. A countersunk portion 52a is formed on the axially outer side of the second bolt insertion holes 52. The countersunk portion 52a is formed so that the inner diameter is larger than the inner diameter of the second bolt insertion holes 52 via a step portion 52b.

[0033] In the carrier 7 configured as described above, a third bearing 33 is fitted into a third bearing housing 35 of the first flange 13. A fourth bearing 34 is fitted into a fourth bearing housing 36 of the second flange 14. Since the third bearing 33 and the fourth bearing 34 have the same configuration, only the fourth bearing 34 will be described below, and the third bearing 33 will be denoted by the same reference numeral as the fourth bearing 34 and will not be described again.

[0034] The fourth bearing 34 is made of high carbon chromium bearing steel such as SUJ2. The fourth bearing 34 is a ball bearing. More specifically, the fourth bearing 34 is a deep groove ball bearing. The fourth bearing 34 includes an annular outer ring 41, an annular inner ring 42 disposed radially inside the outer ring 41, and rolling elements 43 disposed between the outer ring 41 and the inner ring 42. The outer ring 41 is fitted into the fourth bearing housing 36. An outer end surface 41a on the axially outer side of the outer ring 41 abuts against a step portion 36a of the fourth bearing housing 36. This positions the fourth bearing 34 relative to the second flange 14.

[0035] A power transmission pin 9 is inserted into each of the bolt insertion holes 51, 52 of each flange 13, 14. The power transmission pin 9 is made of, for example, aluminum chrome molybdenum steel. The power transmission pin 9 includes a cylindrical shaft portion 61, a male thread portion 62 integrally formed with one axial end of the shaft portion 61, and a head portion 63 integrally formed with the other axial end of the shaft portion 61. The shaft portion 61, the male thread portion 62, and the head portion 63 are arranged coaxially.

[0036] The outer diameter of the shaft portion 61 is equal to or slightly smaller than the inner diameter of the first bolt insertion hole 51 and the inner diameter of the second bolt insertion hole 52 . The male thread portion 62 is formed so that the outer diameter is smaller than the outer diameter of the shaft portion 61 via a thread step portion 62a. The head 63 is formed so that its outer diameter is larger via a head step 63a than the outer diameter of the shaft portion 61. The outer diameter of the head 63 is slightly smaller than the outer diameter of the countersunk portion 52a of the second flange 14.

[0037] With this configuration, the power transmission pin 9 is inserted from the second flange 14 side into the second bolt insertion hole 52 and the first bolt insertion hole 51 in that order, with the male thread portion 62 facing the first flange 13 side. At this time, the head 63 of the power transmission pin 9 is inserted into the countersunk portion 52a of the second bolt insertion hole 52. The head stepped portion 63a of the power transmission pin 9 abuts against the stepped portion 52b of the second bolt insertion hole 52, thereby positioning the power transmission pin 9 in the axial direction with respect to the second flange 14.

[0038] Meanwhile, the male thread portion 62 of the power transmission pin 9 protrudes axially outward through the first bolt insertion hole 51. A flat washer 65 is inserted into the male thread portion 62. A nut 66 is fastened onto the male thread portion 62 from above the flat washer 65. This fixes the power transmission pin 9 to the carrier 7 (first flange 13, second flange 14).

[0039] At this time, an annular first spacer 64a is provided between the inner ring 18 of the first bearing 15 and the flat washer 65. An annular second spacer 64b is provided between the outer ring 41 of the third bearing 33 and the flat washer 65. The thickness T1 of the first spacer 64a is thicker than the thickness T2 of the second spacer 64b. The thicknesses T1 and T2 will be described in more detail below.

[0040] The thickness T1 of the first spacer 64a is a thickness that causes the axially inner end surface 18b of the inner ring 18 of the first bearing 15 to slightly protrude from the inner end surface 13c of the first flange 13. Hereinafter, the conditions that satisfy such a state of the first bearing 15 will be referred to as the first bearing conditions. The thickness T2 of the second spacer 64b is a thickness such that the axially inner end surface 41b of the outer ring 41 of the third bearing 33 is slightly recessed from the inner end surface 13c of the first flange 13. Hereinafter, the conditions that satisfy such a state of the third bearing 33 will be referred to as third bearing conditions.

[0041] With the power transmission pin 9 fixed, two bushes 71, 72 (first bush 71, second bush 72) are fitted between the first flange 13 and the second flange 14 of the shaft portion 61. The bushes 71, 72 are formed of high carbon chromium bearing steel such as SUJ2. That is, the hardness of the bushes 71, 72 is the same as the hardness of the bearings 15, 16, 33, and 34.

[0042] The crankshaft 8 is rotatably supported by the flanges 13, 14 via a third bearing 33 and a fourth bearing 34. The crankshaft 8 is made of, for example, an aluminum alloy, similar to the power transmission pins 9. Alternatively, the crankshaft 8 may be made of, for example, stainless steel or various iron-based metals, similar to the power transmission pins 9.

[0043] The crankshaft 8 is formed to be hollow. On the outer circumferential surface of the crankshaft 8, a first eccentric portion 21a and a second eccentric portion 21b are formed side by side in the axial direction between a third bearing 33 and a fourth bearing 34. The first eccentric portion 21a is disposed on the first flange 13 side. The second eccentric portion 21b is disposed on the second flange 14 side. The eccentric portions 21a, 21b are eccentric from the rotation axis of the crankshaft 8 (carrier 7). The eccentric portions 21a, 21b are shifted in phase angle from each other. For example, the eccentric portions 21a, 21b are shifted in phase angle from each other by 180°.

[0044] The eccentric portions 21a and 21b are provided with bearings 37 and 38 (a fifth bearing 37 and a sixth bearing 38), respectively. These bearings 37 and 38 are, for example, needle bearings. The eccentric portions 21a and 21b rotatably support the oscillating gears 11 and 12 (first oscillating gear 11 and second oscillating gear 12) via bearings 37 and 38, respectively. That is, the oscillating gears 11 and 12 are disposed between the first flange 13 and the second flange 14.

[0045] The two oscillating gears 11, 12 are made of an iron-based material such as chrome molybdenum steel. Crankshaft insertion holes 24a, 24b (first crankshaft insertion hole 24a, second crankshaft insertion hole 24b) that penetrate in the thickness direction are formed in the radial center of the two oscillating gears 11, 12. Bearings 37, 38 are fitted into the crankshaft insertion holes 24a, 24b, respectively. External teeth 23a, 23b that mesh with the internal pin 6 of the case 2 are formed on the outer periphery of the two oscillating gears 11, 12. The number of teeth of each of the external teeth 23a, 23b is less than the number of the internal pin 6 by, for example, one.

[0046] Pin insertion holes 25a, 25b (first pin insertion hole 25a, second pin insertion hole 25b) are formed in the two oscillating gears 11, 12 at positions corresponding to the power transmission pin 9. A shaft portion 61 of the power transmission pin 9 is inserted into each of the pin insertion holes 25a, 25b. A first bushing 71 fitted onto the shaft portion 61 is inserted into the first pin insertion hole 25a of the pin insertion holes 25a, 25b. A second bushing 72 fitted onto the shaft portion 61 is inserted into the second pin insertion hole 25b of the pin insertion holes 25a, 25b.

[0047] With this configuration, the oscillating gears 11, 12 are oscillatingly rotated by the eccentric portions 21a, 21b of the crankshaft 8. The inner diameters of the pin insertion holes 25a, 25b of the oscillating gears 11, 12 are large enough to allow the oscillating rotation of the oscillating gears 11, 12 with the shaft portion 61 of the power transmission pin 9 and the bushes 71, 72 inserted therein.

[0048] <Dimensional relationship between the second flange, second bearing, fourth bearing, and second bush> Next, the dimensional relationships between the second flange 14, the second bearing 16, the fourth bearing 34, and the second bush 72 will be described with reference to FIG. FIG. 2 is an enlarged view of part II in FIG. 2, the axial length L1 of the outer peripheral bearing housing 14a is shorter than the axial length L2 of the inner ring 18 of the second bearing 16. Therefore, the inner end surface 18b of the second bearing 16 protrudes axially inward beyond the inner end surface 14e of the outer peripheral bearing housing 14a (second flange 14). Hereinafter, the condition that satisfies such a state of the second bearing 16 is referred to as the second bearing condition.

[0049] The axial length L3 of the fourth bearing housing 36 is longer than the axial length L4 of the outer ring 41 of the fourth bearing 34. Therefore, the inner end surface 41b of the outer ring 41 of the fourth bearing 34 is recessed from the inner end surface 14e of the fourth bearing housing 36 (second flange 14). Hereinafter, the condition that satisfies such a state of the fourth bearing 34 will be referred to as the fourth bearing condition.

[0050] The radial thickness T3 of the second bushing 72 is greater than the distance T4 between the outer peripheral surface 9a of the power transmission pin 9 and the inner peripheral surface 18c of the inner ring 18 of the second bearing 16. Although not particularly shown, the radial thickness of the first bushing 71 is greater than the distance between the outer peripheral surface 9a of the power transmission pin 9 and the inner peripheral surface 18c of the inner ring 18 of the first bearing 15. Hereinafter, the condition that satisfies such dimensions will be referred to as the outer diameter condition of the bushing.

[0051] In this way, by satisfying the second bearing condition and the outer diameter condition of the bush, the axially outer outer end surface 72a of the second bush 72 contacts only the inner end surface 18b of the inner ring 18 of the second bearing 16. Since the inner end surface 14e of the second flange 14 is formed flat, the outer end surface 72a of the second bush 72 will not contact the fourth bearing housing 36 even if the fourth bearing condition is met.

[0052] The same can be said about the relationship between the first bearing 15 and the first bush 71, and the relationship between the third bearing 33 and the first bush 71. That is, by satisfying the first bearing condition and the outer diameter condition of the bush, an outer end surface 71a (see FIG. 1) on the axially outer side of the first bush 71 comes into contact only with an inner end surface 18b of the inner ring 18 of the first bearing 16. Since the inner end surface 13c of the first flange 13 is formed flat, the outer end surface 71a of the first bush 71 does not come into contact with the first flange 13 even when the third bearing condition is met.

[0053] <Reduction gear operation> Next, the operation of the reducer 1 will be described. For example, when the crankshaft 8 is rotated by an electric motor (not shown), the oscillating gears 11 and 12 rotatably supported by the eccentric portions 21a and 21b are oscillated and rotated. Then, the internal tooth pin 6 of the case 2 meshes with a part of the external teeth 23a and 23b of the oscillating gears 11 and 12. At this time, since the number of teeth of each of the external teeth 23a, 23b is, for example, one less than the number of the internal tooth pins 6, each of the oscillating gears 11, 12 rotates on its axis such that the meshing points of each of the external teeth 23a, 23b with respect to the internal tooth pins 6 (case 2) are shifted sequentially in the circumferential direction. This rotation is decelerated with respect to the rotation of the crankshaft 8.

[0054] A power transmission pin 9 is inserted into the pin insertion holes 25a, 25b of each of the oscillating gears 11, 12. Therefore, when each of the oscillating gears 11, 12 rotates, the rotational force of the oscillating gears 11, 12 in the rotational direction is transmitted to each of the power transmission pins 9 via the bushes 71, 72. That is, the bushes 71, 72 slide with the corresponding oscillating gears 11, 12. Each of the power transmission pins 9 is fixed to the carrier 7 (first flange 13, second flange 14). Therefore, the rotational force of the oscillating gears 11, 12 is transmitted to the carrier 7 via each of the power transmission pins 9. The carrier 7 is rotatably supported by the case 2 via the first bearing 15 and the second bearing 16. As a result, the carrier 7 rotates relative to the case 2. That is, the rotation input to the crankshaft 8 is decelerated and output from the carrier 7.

[0055] Incidentally, the bushes 71 and 72 may move slightly in the axial direction as the oscillating gears 11 and 12 are driven. In this case, the bushes 71 and 72 slide against members located on the axially outer side of the bushes 71 and 72.

[0056] Here, the outer end surface 72a of the second bush 72 contacts only the inner end surface 18b of the inner ring 18 of the second bearing 16. The outer end surface 72a of the second bush 72 does not contact the fourth bearing housing 36. The outer end surface 71a (see FIG. 1) of the first bush 71 contacts only the inner end surface 18b of the inner ring 18 of the first bearing 15. The outer end surface 71a of the first bush 71 does not contact the first flange 13. For this reason, the contact area at the outer end surfaces 71a, 72a of each bush 71, 72 can be made smaller than when the outer end surfaces 71a, 72a of each bush 71, 72 contact the corresponding flanges 13, 14 as well as the corresponding bearings 15, 16.

[0057] In this manner, in the embodiment described above, the outer end faces 71a, 72a of the bushes 71, 72 contact only the inner end faces 18b of the inner rings 18 of the corresponding bearings 15, 16. This makes it possible to minimize the contact area of ​​the outer end faces 71a, 72a of the bushes 71, 72, thereby reducing the contact resistance of the bushes 71, 72. This reliably improves the drive efficiency of the reducer 1.

[0058] Since the outer end surface 72a of the second bush 72 contacts only the inner end surface 18b of the inner ring 18 of the second bearing 16, a minute gap G1 is formed between the outer end surface 72a of the second bush 72 and the inner end surface 14e of the outer bearing housing 14a. Moreover, this minute gap G1 is surrounded by the outer end surface 72a of the second bush 72, the outer peripheral surface 9a of the power transmission pin 9, the inner end surface 14e of the outer bearing housing 14a, and the inner peripheral surface 18c of the inner ring 18 of the second bearing 16. For this reason, it is possible to actively retain lubricating oil in the minute gap G1. Therefore, the driving efficiency of the reducer 1 can be further improved. The same is true between the outer end surface 71a of the first bush 71 and the first flange 13.

[0059] By satisfying the second bearing condition and the outer diameter condition of the bushing, the outer end surface 72a of the second bushing 72 can be reliably brought into contact with only the inner ring 18 of the second bearing 16. By satisfying the first bearing condition and the outer diameter condition of the bushing, the outer end surface 71a of the first bushing 71 can be reliably brought into contact with only the inner ring 18 of the first bearing 16.

[0060] Moreover, the hardness of each bush 71, 72 is the same as that of each bearing 15, 16, 33, 34. If the hardness of the first bearing 15 or the second bearing 16 differs from that of each bush 71, 72, wear of either the bearings 15, 16 or the bushes 71, 72 will be accelerated. As a result, the drive efficiency of the reducer 1 may decrease. Therefore, by making the hardness of each bush 71, 72 the same as that of each bearing 15, 16, 33, 34, it is possible to suppress the accelerated wear of either the bearings 15, 16 or the bushes 71, 72. Therefore, the drive efficiency of the reducer 1 can be improved more reliably.

[0061] [Variations] The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention.

[0062] For example, in the above embodiment, the reducer 1 has been described as a rotating device. However, the present invention is not limited to this, and the configuration of the reducer 1 described above can be adopted in various rotating devices. The rotating device may include a cylindrical first member, an example of which is the case 2; a second member, an example of which is the carrier 7 rotatably supported on the inner circumferential surface of the first member via a bearing; a pin inserted into a pin insertion hole formed in the second member; a bush fitted to the outer circumferential surface of the pin; and a third member, an example of which is the oscillating gears 11, 12 that engage with the pin via the bush and transmit a rotational force between the pin and the second member via the pin. The bush and the bearing may be arranged side by side in the axial direction.

[0063] In the above embodiment, the reducer 1 including the speed reduction mechanism 30 that reduces the speed of rotation of the crankshaft 8 and outputs it has been described. However, the present invention is not limited to this, and the power transmission pin 9 may be used in a speed increaser instead of the speed reduction mechanism 30. Furthermore, the power transmission pin 9 may be used in a rotating device provided with a member that replaces the speed reduction mechanism 30 (the carrier 7 or the oscillating gears 11 and 12). It is only necessary that the member that replaces the speed reduction mechanism 30 has a pin insertion hole (pin insertion holes 25a and 25b) for inserting the power transmission pin 9 therein.

[0064] In the above embodiment, the reduction mechanism 30 includes one crankshaft 8, and the rotation axis of the carrier 7 and the rotation axis of the crankshaft 8 are aligned. However, the present invention is not limited to this, and the reduction mechanism 30 may be a so-called eccentric oscillating type reduction mechanism that oscillates and rotates the two oscillating gears 11, 12. For example, three crankshafts 8 may be provided and arranged around the rotation axis of the carrier 7. The two oscillating gears 11, 12 may be oscillated and rotated by these crankshafts 8.

[0065] In the above embodiment, the bushes 71 and 72 are formed of the same material as the bearings 15, 16, 33, and 34. As a result, the hardness of the bushes 71 and 72 is the same as the hardness of the bearings 15, 16, 33, and 34. However, this is not limited to this, and the bushes 71 and 72 do not have to be formed of the same material as the bearings 15, 16, 33, and 34. The hardness of the bushes 71 and 72 does not have to be completely the same as the hardness of the bearings 15, 16, 33, and 34, but may be about the same. In this specification, the meaning that the hardness of the bushes 71 and 72 is the same as the hardness of the bearings 15, 16, 33, and 34 also includes the meaning that they are about the same. The wording "about the same" refers to, for example, an absolute value of the difference in Rockwell hardness of 6HRC or less.

[0066] In the above embodiment, the outer end surface 71a of each bush 71, 72 is in contact only with the inner end surface 18b of the inner ring 18 of the corresponding first bearing 15 and second bearing 16. However, this is not limited to the above, and it is sufficient that the outer end surface 71a of each bush 71, 72 is in contact only with at least the bearings 15, 16, 33, 34. It is sufficient that the outer end surface 71a of each bush 71, 72 is not in contact with the carrier 7 (first flange 13, second flange 14). A specific example will be described with reference to FIG. 3.

[0067] Fig. 3 is a partially enlarged view of the speed reducer 1 in a modified example. Fig. 3 corresponds to Fig. 2 described above. 3, the outer end surface 71a of each bush 71, 72 may be in contact with only the inner end surface 41b of the outer ring 41 of the corresponding third bearing 33 and fourth bearing 34. The dimensional relationship of each part in such a case will be described below.

[0068] <Dimensional Relationship Between the Second Flange, the Second Bearing, the Fourth Bearing, and the Second Bush in the Modified Example> That is, the axial length L1' of the outer peripheral bearing housing 14a is equal to or slightly longer than the axial length L2' of the inner ring 18 of the second bearing 16. Therefore, the inner end surface 18b of the second bearing 16 and the inner end surface 14e of the outer peripheral bearing housing 14a (second flange 14) are on the same plane. Alternatively, the inner end surface 18b of the second bearing 16 is recessed from the inner end surface 14e of the outer peripheral bearing housing 14a (second flange 14). Hereinafter, the condition that satisfies such a state of the second bearing 16 will be referred to as the second bearing condition of the modified example.

[0069] The axial length L3' of the fourth bearing housing 36 is shorter than the axial length L4' of the outer ring 41 of the fourth bearing 34. Therefore, the inner end surface 41b of the outer ring 41 of the fourth bearing 34 protrudes axially inward beyond the inner end surface 14e of the fourth bearing housing 36 (second flange 14). Hereinafter, the condition that satisfies such a state of the fourth bearing 34 will be referred to as the fourth bearing condition of the modified example.

[0070] The radial thickness T3 of the second bushing 72 is greater than the distance T5 between the outer peripheral surface 9a of the power transmission pin 9 and the outer peripheral surface 41c of the outer ring 41 of the fourth bearing 34. Although not particularly shown, the radial thickness of the first bushing 71 is greater than the distance between the outer peripheral surface 9a of the power transmission pin 9 and the outer peripheral surface 41c of the outer ring 41 of the third bearing 33. Hereinafter, the condition that satisfies such dimensions will be referred to as the outer diameter condition of the modified bushing.

[0071] In this way, by satisfying the second bearing condition of the modified example and the outer diameter condition of the bush of the modified example, the outer end surface 72a on the axially outer side of the second bush 72 contacts only the inner end surface 41b of the outer ring 41 of the fourth bearing 34. Since the inner end surface 14e of the second flange 14 is formed flat, the outer end surface 72a of the second bush 72 does not contact the outer peripheral bearing housing 14a even when the second bearing condition of the modified example is met.

[0072] The same conditions as those described above can be adopted for the conditions between the first bearing 15 and the first bush 71, and the conditions between the third bearing 33 and the first bush 71. This allows the outer end surface 71a of the first bush 71 to contact only the inner end surface 41b of the outer ring 41 of the third bearing 33. Therefore, this modified example provides the same effects as the above-described embodiment.

[0073] In this modification, a minute gap G2 is formed between the outer end surface 72a of the second bushing 72 and the inner end surface 14e of the fourth bearing housing 36. The minute gap G2 is surrounded by the outer end surface 72a of the second bushing 72, the outer peripheral surface 9a of the power transmission pin 9, the inner end surface 14e of the fourth bearing housing 36, and the outer peripheral surface 41c of the outer ring 41 of the fourth bearing 34. This makes it possible to actively retain lubricating oil in the minute gap G2. The same applies to the gap between the outer end surface 71a of the first bushing 71 and the first flange 13.

[0074] Alternatively, the outer end surface 71a of the first bushing 71 may be in contact with both the inner ring 18 of the first bearing 15 and the outer ring 41 of the third bearing 33. The outer end surface 72a of the second bushing 72 may be in contact with both the inner ring 18 of the second bearing 16 and the outer ring 41 of the fourth bearing 34. Even in this configuration, the contact area at the outer end surface 71a of each bushing 71, 72 can be made smaller than when the outer end surface 71a of each bushing 71, 72 contacts the corresponding bearings 15, 16 and the corresponding flanges 13, 14.

[0075] Among the embodiments disclosed in this specification, those that are composed of multiple objects may be integrated, and conversely, those that are composed of one object may be divided into multiple objects. Regardless of whether they are integrated or not, it is sufficient that they are configured to achieve the object of the invention. [Explanation of symbols]

[0076] 1...Reduction gear (rotating device) 2...Case (internal gear, first member) 2b…Inner peripheral surface 6...Inner tooth pin (inner tooth) 7...Carrier (second member) 8…Crankshaft 9…Power transmission pin (pin) 9a...Outer surface 11...First oscillating gear (third member) 12...Second oscillating gear (third member) 13...First flange (second member) 13c…Inner end surface 14...Second flange (second member) 14e…Inner end surface 15…First bearing (bearing, first bearing) 16...2nd bearing (bearing, 1st bearing) 18…Inner circle 18b…Inner end surface 18c…Inner peripheral surface 21a...First eccentric part (eccentric part) 21b...Second eccentric part (eccentric part) 23a…external teeth 23b…external teeth 25a…First pin insertion hole (pin insertion hole) 25b…Second pin insertion hole (pin insertion hole) 33…Third bearing (second bearing) 34…4th bearing (2nd bearing) 41…Outer ring 41b…Inner end surface 41c...Outer surface 71…First Bush (Bush) 71a…Outer end face (end face) 72…Second Bush (Bush) 72a…Outer end face (end face) T3…Thickness T4,T5…distance

Claims

1. A cylindrical first member; a second member that is rotatably supported on an inner peripheral surface of the first member via a bearing and has a pin insertion hole formed therein along the direction of the rotation axis; a pin that is inserted into the pin insertion hole of the second member and supported by the second member; a bush fitted to an outer peripheral surface of the pin and arranged side by side with the bearing in the direction of the rotation axis; a third member that engages with the pin via the bush and transmits a rotational force between the third member and the second member via the pin; Equipped with The end surface of the bush on the bearing side is in contact with only the bearing. Rotating device.

2. the bearing protrudes beyond an end surface of the second member on the bushing side, A radial thickness of the bush is greater than a distance between the outer circumferential surface of the pin and the inner circumferential surface of the bearing. The rotating device according to claim 1 .

3. The hardness of the bearing and the hardness of the bush are the same. The rotating device according to claim 1 or 2.

4. a cylindrical internal gear having internal teeth; a carrier that is rotatably supported on an inner peripheral surface of the internal gear via a first bearing and that is provided with a first pin insertion hole that is aligned along the direction of the rotation axis; a crankshaft that is rotatably supported by the carrier via a second bearing and has an eccentric portion; an oscillating gear that is rotatably supported by the eccentric portion of the crankshaft and that is provided with external teeth that mesh with the internal teeth and a second pin insertion hole; A pin to be inserted into the first pin insertion hole and the second pin insertion hole; a bushing fitted to a portion of an outer circumferential surface of the pin that is inserted into the second pin insertion hole; Equipped with The first bearing and the second bearing are arranged side by side in a radial direction, The first pin insertion hole and the second pin insertion hole are disposed opposite to each other in the direction of the rotation axis, The first bearing, the second bearing and the bush are arranged side by side in the direction of the rotation axis, an end surface of the bush on the side of the first bearing and the second bearing is in contact with at least one of the first bearing and the second bearing; Rotating device.

5. the first bearing protrudes beyond an end surface of the carrier on the bush side, a radial thickness of the bush is greater than a distance between the outer circumferential surface of the pin and an inner circumferential surface of the first bearing; The rotating device according to claim 4.

6. the second bearing protrudes beyond an end surface of the carrier on the bushing side, a radial thickness of the bush is greater than a distance between the outer circumferential surface of the pin and the outer circumferential surface of the second bearing; The rotating device according to claim 4 or 5.

7. the hardness of the first bearing, the hardness of the second bearing, and the hardness of the bush are the same; The rotating device according to claim 4.

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