阅读说明：本技术 轴保持机构和减速器 (Shaft holding mechanism and speed reducer ) 是由 纪平诚人 于 2021-04-23 设计创作，主要内容包括：本发明涉及轴保持机构和减速器,本发明的轴保持机构具有：壳体(5),其形成收纳润滑剂的收纳空间(S)；输入轴(7),其穿过形成于壳体(5)的贯通孔(36)而贯通壳体(5)；密封环(123),其在贯通孔(36)内包围输入轴(7)的周围,并将输入轴(7)和壳体(5)之间密闭；以及轴承(115),其设于相对于密封环(123)而言与收纳空间(S)相反的一侧,并在贯通孔(36)内将输入轴(7)支承成能够旋转。(The present invention relates to a shaft holding mechanism and a speed reducer, the shaft holding mechanism of the present invention comprises: a housing (5) that forms a housing space (S) for housing a lubricant; an input shaft (7) that penetrates the housing (5) through a through hole (36) formed in the housing (5); a seal ring (123) that surrounds the periphery of the input shaft (7) within the through hole (36) and seals the space between the input shaft (7) and the housing (5); and a bearing (115) which is provided on the opposite side of the seal ring (123) from the housing space (S) and rotatably supports the input shaft (7) in the through hole (36).)

1. A shaft holding mechanism, wherein,

the shaft holding mechanism includes:

a base portion forming a housing space for housing a lubricant;

a shaft penetrating the base portion through a through hole formed in the base portion;

a seal member that surrounds the periphery of the shaft in the through hole and seals a space between the shaft and the base; and

and a bearing provided on the opposite side of the seal member from the housing space and rotatably supporting the shaft in the through hole.

2. The shaft holding mechanism according to claim 1,

the seal member is not disposed on a side opposite to the housing space with respect to the bearing.

3. The shaft holding mechanism according to claim 1,

the shaft is configured to be removable from the base in a state of being separated from the sealing member,

the inner diameter of the sealing member is smaller than the inner diameter of the bearing.

4. The shaft holding mechanism according to claim 3,

a speed reduction mechanism portion is provided in the housing space, and the speed reduction mechanism portion is connected to the shaft.

5. The shaft holding mechanism according to claim 4,

a gear connected to the reduction mechanism portion is provided at an end of the shaft on the side of the housing space with respect to the seal member,

the gear has an outer diameter smaller than an inner diameter of the seal member.

6. The shaft holding mechanism according to claim 3,

a restricting member is detachably provided on the base portion on a side opposite to the seal member with respect to the bearing, the restricting member restricting movement of the bearing in a direction away from the seal member.

7. A speed reducer, wherein,

the speed reducer is provided with:

a housing forming a housing space for housing a lubricant;

a speed reduction mechanism portion housed in the housing space;

a shaft that penetrates the housing through a through hole formed in the housing and is connected to the reduction mechanism section in the housing;

a seal member that surrounds the periphery of the shaft in the through hole and seals a space between the shaft and the housing; and

and a bearing provided on the opposite side of the seal member from the housing space and rotatably supporting the shaft in the through hole.

Technical Field

The invention relates to a shaft holding mechanism and a speed reducer.

This application claims priority based on Japanese patent application No. 2020-.

Background

A rotating device used for an industrial robot or the like is equipped with a speed reducer for reducing a driving torque of a motor. Such a reduction gear includes a housing and a plurality of gears housed in the housing (see, for example, patent document 1 below). The housing is formed with a through hole through which an input shaft of the motor passes. A bearing is provided in the through hole to rotatably support the input shaft.

However, a lubricant is sealed in the case of the reduction gear for the purpose of ensuring lubricity between the gears, cooling the seal member, and the like. The lubricant is restricted from flowing out of the housing by a seal member provided in the through hole.

Documents of the prior art

Patent document

Patent document 1: japanese Kokai publication Sho 59-131641

Disclosure of Invention

Problems to be solved by the invention

However, in the above-described conventional technique, the seal member is disposed outside the housing with respect to the bearing, and therefore the lubricant hardly reaches the seal member. Therefore, the sealing member may become high temperature due to frictional heat or the like generated between the sealing member and the input shaft.

The invention provides a shaft holding mechanism and a speed reducer capable of effectively supplying lubricant to a sealing component.

Means for solving the problems

In order to solve the above problems, the present invention adopts the following technical means.

The shaft holding mechanism according to an aspect of the present invention includes: a base portion forming a housing space for housing a lubricant; a shaft penetrating the base portion through a through hole formed in the base portion; a seal member that surrounds the periphery of the shaft in the through hole and seals a space between the shaft and the base; and a bearing provided on the opposite side of the seal member from the housing space and rotatably supporting the shaft in the through hole.

By using the technical scheme, the condition that the bearing blocks the flow of the lubricant in the accommodating space can be inhibited. Therefore, the lubricant can be efficiently made to reach the seal member. As a result, the sealing member can be prevented from becoming high in temperature due to frictional heat or the like generated between the sealing member and the shaft. In this case, for example, thermal deformation of the sealing member or the like can be suppressed, and the sealing property can be maintained for a long period of time.

In the shaft holding mechanism according to the above aspect, it is preferable that the seal member is not disposed on a side opposite to the housing space with respect to the bearing.

In the shaft holding mechanism according to the above aspect, it is preferable that the shaft is configured to be removable from the base in a state separated from the seal member, and an inner diameter of the seal member is smaller than an inner diameter of the bearing.

In the shaft holding mechanism according to the above aspect, it is preferable that a speed reduction mechanism portion is provided in the housing space, and the speed reduction mechanism portion is connected to the shaft.

In the shaft holding mechanism according to the above aspect, it is preferable that a gear is provided at an end of the shaft located on the housing space side with respect to the seal member, the gear is connected to the speed reduction mechanism portion, and an outer diameter of the gear is smaller than an inner diameter of the seal member.

In the shaft holding mechanism according to the above aspect, it is preferable that a restricting member that restricts movement of the bearing in a direction away from the seal member is detachably provided on the base portion on a side of the base portion opposite to the seal member with respect to the bearing.

A reduction gear according to an aspect of the present invention includes: a housing forming a housing space for housing a lubricant; a speed reduction mechanism portion housed in the housing space; a shaft that penetrates the housing through a through hole formed in the housing and is connected to the reduction mechanism section in the housing; a seal member that surrounds the periphery of the shaft in the through hole and seals a space between the shaft and the housing; and a bearing provided on the opposite side of the seal member from the housing space and rotatably supporting the shaft in the through hole.

ADVANTAGEOUS EFFECTS OF INVENTION

With the above-described aspects, the lubricant can be efficiently supplied to the seal member.

Drawings

Fig. 1 is a sectional view of a reduction gear according to embodiment 1.

Fig. 2 is an enlarged view of a portion II of fig. 1.

Fig. 3 is a sectional view of the reduction gear of embodiment 2.

Fig. 4 is a partial sectional view of the speed reducer of embodiment 3.

Description of the reference numerals

5. A housing (base); 6. a speed reduction mechanism section; 7. an input shaft (shaft); 22. a 2 nd housing (base); 36. a through hole; 42. component 2 (base); 57. 2 nd through hole (through hole); 117. a retainer ring (restricting member); 123. a seal ring (seal member); 131. an input gear (gear); 230. an input shaft (shaft); 236. a bearing; 237. a retainer ring (restricting member); 257. an input gear (gear); 311. a through hole; 342. an input gear (gear); 345. a bearing; 346. a retainer ring (restricting member); 347. a seal ring (seal member).

Detailed Description

Next, embodiments of the present invention will be described based on the drawings. In the embodiments and modifications described below, the same reference numerals are given to corresponding components, and descriptions thereof may be omitted. In the following description, for example, expressions indicating relative or absolute arrangements such as "parallel", "orthogonal", "central", and "coaxial" indicate not only such arrangements as they are strictly described, but also a state in which relative displacements occur with a tolerance, an angle of a degree to obtain the same function, and a distance.

(embodiment 1)

[ speed reducer 1]

Fig. 1 is a sectional view of a speed reducer 1.

As shown in fig. 1, the speed reducer 1 is provided at a coupling portion (joint portion) of a pair of arms rotatably coupled to each other in, for example, an industrial robot. The speed reducer 1 reduces the speed of the driving torque input from a motor (not shown) and outputs the reduced driving torque. On the output side of the reduction gear 1, for example, a grip head is attached.

The speed reducer 1 includes a housing (base) 5, a speed reduction mechanism 6, and an input shaft (shaft) 7.

< housing 5 >

The housing 5 forms a housing space S for housing the reduction mechanism portion 6. The case 5 is a bottomed cylinder as a whole by combining the 1 st case 21 and the 2 nd case 22. In the following description, the direction along the axis O1 of the housing 5 is simply referred to as the axial direction, the direction intersecting the axis O1 when viewed from the axial direction is referred to as the radial direction, and the direction revolving around the axis O1 is referred to as the circumferential direction.

The 1 st housing 21 has a cylindrical portion 21a and a flange portion 21 b.

The inner circumferential surface of the cylindrical portion 21a is provided with internal teeth 24. The internal teeth 24 have: a plurality of pin grooves 25 formed in the inner circumferential surface of the tube portion 21 a; and inner pins 26 housed in the pin grooves 25, respectively.

The pin groove 25 is open on the inner peripheral surface of the cylindrical portion 21a, and extends in the axial direction. The pin grooves 25 are formed at equal intervals in the circumferential direction.

The inner pin 26 is formed in a cylindrical shape extending in the axial direction. The inner pin 26 is housed in the pin groove 25 in a state where a part thereof protrudes radially inward from the pin groove 25. The inner rack pin 26 is held by the pin groove 25 so as to be rotatable about an axis parallel to the axis O1. The internal teeth 24 may be formed integrally with the cylindrical portion 21 a.

The flange portion 21b protrudes radially outward from the center portion of the cylindrical portion 21a in the axial direction.

The 2 nd case 22 closes the opening of the 1 st case 21 from the 1 st side in the axial direction. The 2 nd case 22 is formed in a bottomed cylindrical shape having a 2 nd side opening in the axial direction. The 1 st housing 21 described above is assembled to the 2 nd housing 22 in a state where the cylindrical portion 21a is fitted into the peripheral wall 31 of the 2 nd housing 22 and the flange portion 21b abuts against the peripheral wall 31 in the axial direction. Further, the sealing material 28 is interposed between the outer peripheral surface of the tube portion 21a and the inner peripheral surface of the peripheral wall 31.

The bottom wall 32 of the 2 nd housing 22 protrudes radially inward from the 1 st side end edge in the axial direction of the peripheral wall 31. The bottom wall 32 is formed in a ring shape. A support cylinder 35 is formed on the inner periphery of the bottom wall 32. The support cylinder 35 is coaxial with the axis O1 and extends to the 1 st side in the axial direction. The inside of the support tube 35 constitutes a through hole 36 connecting the inside and the outside of the housing 5.

Fig. 2 is an enlarged view of a portion II of fig. 1.

As shown in fig. 2, the inner diameter of the support tube 35 is gradually reduced from the 1 st side to the 2 nd side in the axial direction. Specifically, the large diameter portion 37, the medium diameter portion 38, and the small diameter portion 39 of the support cylinder 35 are axially connected. The large diameter portion 37 is formed with a groove 40. The groove 40 extends over the entire circumference on the inner circumferential surface of the large diameter portion 37. The 1 st stepped surface 37a connecting the large diameter portion 37 and the middle diameter portion 38 and the 2 nd stepped surface 38a connecting the middle diameter portion 38 and the small diameter portion 39 are formed as flat surfaces orthogonal to the axial direction, respectively.

< speed reduction mechanism part 6 >

As shown in fig. 1, the reduction mechanism portion 6 includes a carrier 11, a plurality of oscillating gears (a 1 st oscillating gear 12 and a 2 nd oscillating gear 13), and a plurality of crankshafts 14. The speed reduction mechanism portion 6 maintains lubrication performance by the lubricant sealed in the housing space S.

The carrier 11 is an output portion of the reduction gear 1. The carrier 11 is provided rotatably around an axis O1 inside the casing 5. The carrier 11 of the present embodiment has a 1 st block 41 and a 2 nd block 42.

The 1 st block 41 is disposed on the 1 st side in the axial direction in the housing 5 (the right side of the paper in fig. 1, the same applies hereinafter). The 1 st block 41 is formed in a disc shape disposed coaxially with the axis O1. The bearing 43 is interposed between the outer peripheral surface of the 1 st block 41 and the inner peripheral surface of the cylindrical portion 21 a. Thus, the 1 st module 41 is supported by the housing 5 so as to be rotatable about the axis O1.

A 1 st through hole 44 that penetrates the 1 st block 41 in the axial direction is formed in the radial direction center portion of the 1 st block 41. A plurality of 1 st shaft support holes 45 are formed in an outer peripheral portion of the 1 st block 41. The 1 st shaft support hole 45 has a tapered portion whose inner diameter gradually decreases toward the 1 st side in the axial direction. The 1 st shaft support holes 45 are formed at intervals in the circumferential direction.

The 2 nd module 42 is disposed on the 2 nd side in the axial direction with respect to the 1 st module in the housing 5. The 2 nd assembly 42 has a base plate 50 and a support post 51.

The base plate 50 is formed in a disc shape disposed coaxially with the axis O1. The base plate 50 closes an opening of the 1 st case 21 (the cylindrical portion 21a) on the 2 nd side (left side of the paper surface in fig. 1, the same applies hereinafter) in the axial direction. The bearing 53 is interposed between the outer peripheral surface of the substrate 50 and the inner peripheral surface of the cylindrical portion 21 a. Thereby, the 2 nd module 42 is supported by the housing 5 so as to be rotatable about the axis O1.

The seal ring 55 is interposed between the outer peripheral surface of the substrate 50 and the inner peripheral surface of the cylindrical portion 21a, and is positioned on the 2 nd side (opposite side to the 1 st block 41) in the axial direction with respect to the bearing 53. The seal ring 55 surrounds the periphery of the substrate 50. The seal ring 55 is in close contact with the outer peripheral surface of the substrate 50 and the inner peripheral surface of the cylindrical portion 21 a. Thereby, the seal ring 55 blocks the connection between the inside and the outside of the housing 5 via the opening of the 2 nd housing 22. The seal ring 55 is configured to be slidable on at least one of the substrate 50 and the cylindrical portion 21a (the substrate 50 in the present embodiment) in accordance with the rotation of the substrate 50.

A 2 nd through hole 57 penetrating the substrate 50 in the axial direction is formed in the center portion of the substrate 50 in the radial direction. The 2 nd through hole 57 is closed by a center lid 58 a. A plurality of 2 nd shaft support holes 59 are formed in the outer peripheral portion of the base plate 50. The 2 nd shaft support hole 59 has a tapered portion whose inner diameter is gradually reduced toward the 2 nd side in the axial direction. The 2 nd shaft support holes 59 are axially opposed to the 1 st shaft support holes 45 described above, respectively. Further, the 2 nd shaft support hole 59 is closed by an outer peripheral cover 58 b.

The support post 51 protrudes from a portion of the base plate 50 located between the adjacent 2 nd axial support holes 59 toward the 1 st side in the axial direction. The support column 51 is fixed to the 1 st block 41 by a bolt 60 or the like in a state of being abutted against the 1 st block 41 in the axial direction. Thereby, the 1 st block 41 and the 2 nd block 42 rotate integrally with respect to the housing 5.

The 1 st oscillating gear 12 and the 2 nd oscillating gear 13 are disposed inside the cylindrical portion 21a in an axially overlapping state. The 1 st and 2 nd oscillating gears 12, 13 are formed to have an outer diameter slightly smaller than the inner diameter of the cylindrical portion 21 a. External teeth 12a are formed on the outer peripheral surface of the 1 st oscillating gear 12. The 2 nd oscillating gear 13 has external teeth 13a formed on its outer peripheral surface. The external teeth 12a of the 1 st oscillating gear 12 and the external teeth 13a of the 2 nd oscillating gear 13 mesh with the internal teeth 24 (internal gear pins 26), respectively. The number of teeth of the external teeth 12a, 13a is set to be slightly smaller (for example, one smaller) than the number of internal pins 26 (pin grooves 25). Further, the oscillating gear may be one.

A 1 st central hole 62 is formed in the center of the 1 st oscillating gear 12. A 2 nd central hole 63 is formed in a central portion of the 2 nd oscillating gear 13. The inner diameters of the center holes 62 and 63 are equal to the inner diameter of the 1 st through hole 44.

A plurality of 1 st escape holes 65 are formed at an outer circumferential portion of the 1 st swing gear 12. The 1 st avoidance holes 65 are formed at intervals in the circumferential direction. A plurality of 2 nd escape holes 66 are formed at an outer circumferential portion of the 2 nd swing gear 13. The 2 nd avoidance holes 66 are formed at the same pitch as the 1 st avoidance holes 65 at intervals in the circumferential direction. The escape holes 65 and 66 are penetrated by the corresponding support columns 51 of the plurality of support columns 51. The inside diameter of the relief holes 65, 66 is larger than the outside diameter of the pillar 51. This prevents the support column 51 from interfering with the operation of the oscillating gears 12 and 13.

A 1 st passing hole 67 is formed in a portion of the outer peripheral portion of the 1 st swing gear 12 between the adjacent 1 st avoiding holes 65. A 2 nd passing hole 68 is formed in a portion of the outer peripheral portion of the 2 nd swing gear 12 between the adjacent 2 nd avoidance holes 66. The through holes 67 and 68 are arranged at the same pitch as the shaft support holes 45 and 46.

The crankshaft 14 functions as a power transmission unit between the carrier 11 and the oscillating gears 12 and 13. The crankshaft 14 passes through the corresponding shaft support holes 45, 46 and the through holes 67, 68, and is bridged between the 1 st block 41 and the base plate 50. Specifically, the crankshaft 14 includes a main shaft 71, a 1 st eccentric portion 72, a 2 nd eccentric portion 73, and a protruding portion 74.

The spindle 71 extends along an axis O2 that is parallel to the axis O1. The 1 st end of the main shaft 71 in the axial direction is supported by a bearing 76 so as to be rotatable in the 1 st shaft support hole 45. The 2 nd axial end of the main shaft 71 is rotatably supported in the 2 nd shaft support hole 46 by a bearing 77. The bearings 76 and 77 are angular contact bearings having cylindrical rollers as rolling elements, for example.

The 1 st eccentric portion 72 is formed in a portion of the main shaft 71 located within the 1 st through hole 67. The axis O3 of the 1 st eccentric portion 72 is eccentric with respect to the axis O2 of the main shaft 71. The 1 st eccentric portion 72 is supported by an eccentric portion bearing 81 so as to be rotatable in the 1 st through hole 67.

The 2 nd eccentric portion 73 is formed in a portion of the main shaft 71 located within the 2 nd through hole 68. The axis O4 of the 2 nd eccentric portion 73 is eccentric with respect to the axis O2 of the main shaft 71. The 2 nd eccentric portion 73 is supported by an eccentric portion bearing 82 so as to be rotatable in the 2 nd through hole 68. The phases of the eccentric portions 72 and 73 are shifted by, for example, 180 ° about the axis O2.

The protrusion 74 protrudes from the spindle 71 toward the 1 st side in the axial direction. A transmission gear 85 is attached to the projection 74.

< input shaft 7 >

As shown in fig. 2, the input shaft 7 rotates about the axis O1 in accordance with the rotation of the motor, thereby transmitting the driving torque of the motor to the speed reduction mechanism 6. The input shaft 7 is a combination of an outer shaft 100, an inner shaft 101, and a gear shaft 102.

The outer shaft 100 is a hollow circular shaft extending along the axis O1. The motor is coupled to the outer shaft 100 from the 1 st axial side. An enlarged portion 110 having an enlarged outer diameter with respect to a central portion of the outer shaft 100 is formed at the 2 nd axial end of the outer shaft 100. A groove 111 is formed in the outer peripheral surface of the enlarged portion 110. The groove 111 extends over the entire circumference of the outer circumferential surface of the enlarged portion 110 in the circumferential direction. A projection 112 projecting radially outward is formed on a portion of the enlarged portion 110 located on the 1 st side in the axial direction with respect to the groove 111. The protrusion 112 extends, for example, over the entire circumference of the enlarged portion 110.

The input shaft 7 is rotatably supported by the housing 5 via a bearing 115 interposed between the enlarged portion 110 and the support cylinder 35. The outer race 115a of the bearing 115 is inserted into the large diameter portion 37 of the support tube 35. The outer ring 115a is held between the 1 st step surface 37a and a retainer ring (restricting member) 117 fitted into the groove 40. The retainer 117 is formed in an annular shape with a part cut off in the circumferential direction, such as a C-ring or an E-ring. The retainer 117 is fitted into the groove 40 with its inner peripheral portion protruding from the inner peripheral surface of the large diameter portion 37. The retainer ring 117 is configured to be elastically deformable so as to expand or contract in the radial direction. Therefore, the retainer 117 is configured to be attachable to and detachable from the groove 40 by contracting from a natural length state using a tool or the like, for example.

The axial 2 nd side end surface of the outer ring 115a abuts on the 1 st step surface 37 a. The 1 st end surface in the axial direction of the outer ring 115a abuts against the retainer 117. Thereby, the axial movement of the outer ring 115a relative to the housing 5 is restricted in the through hole 57.

The inner race 115b in the bearing 115 is held between the protrusion 112 of the enlarged portion 110 and the retainer 119 fitted into the groove 111. Specifically, the enlarged portion 110 is inserted into the inner ring 115 b. The retainer ring 119 is fitted into the groove 111 with its inner peripheral portion protruding from the outer peripheral surface of the enlarged portion 110. The 1 st end surface in the axial direction of the inner ring 115b abuts on the projection 112. The axial 2 nd side end surface of the inner ring 115b abuts against the retainer ring 119. Thereby, the movement of the inner race 115b in the axial direction with respect to the input shaft 7 is restricted.

Inner shaft 101 is a hollow circular shaft extending along axis O1. Specifically, inner shaft 101 has fixing portion 120 and protrusion 121 connected to axial 2 nd side with respect to fixing portion 120.

The fixing portion 120 is fixed to the outer shaft 100 by press fitting or the like. However, the inner shaft 101 may be fixed to the outer shaft 100 by a method other than press fitting (for example, a key, a D-shaped notch, or the like) as long as it cannot rotate relative to the outer shaft 100.

The protrusion 121 protrudes from the outer shaft 100 toward the 2 nd side in the axial direction. The protruding portion 121 has an outer diameter larger than that of the fixing portion 120 and smaller than that of the enlarged portion 110. A seal ring (seal member) 123 is interposed between the protrusion 121 and the intermediate diameter portion 38 of the support cylinder 35. The seal ring 123 surrounds the periphery of the protrusion 121. The inner diameter of the seal ring 123 is smaller than the inner diameter of the bearing 115 (inner ring 115 b). The seal ring 123 is in close contact with the outer peripheral surface of the protruding portion 121 and the inner peripheral surface of the intermediate portion 38. Thus, the seal ring 123 blocks the connection between the inside and the outside of the housing 5 at the 2 nd side (the housing space S side) in the axial direction from the bearing 115 in the through hole 36. That is, the bearing 115 is disposed on the atmospheric side with respect to the seal ring 123. The seal ring 123 is configured to be slidable on at least one of the outer peripheral surface of the protruding portion 121 and the inner peripheral surface of the intermediate portion 38 (the protruding portion 121 in the present embodiment) in accordance with the rotation of the input shaft 7. Further, the movement of the seal ring 123 in the axial direction relative to the housing 5 between the 2 nd step surface 38a and the bearing 115 is restricted.

The gear shaft 102 is a solid circular shaft extending along the axis O1. The gear shaft 102 has: a fixed portion 130; and an input gear (gear) 131 connected to the 2 nd side in the axial direction with respect to the fixed portion 130.

Fixing portion 130 is fixed inside inner shaft 101 by press fitting or the like.

The input gear 131 protrudes from the inner shaft 101 to the 2 nd side in the axial direction. The input gear 131 meshes with the transmission gear 85 in the housing 5. The maximum outer diameter of the input gear 131 is smaller than the inner diameter of the seal ring 123. The shaft holding mechanism of the present embodiment is configured by at least the input shaft 7, the housing 5, the bearing 115, and the seal ring 123.

As shown in fig. 1, in the reduction gear 1 of the present embodiment, the input shaft 7 is rotated by the driving torque of the motor, and the driving torque of the motor is input to the reduction mechanism portion 6 through the transmission gear 85. When the respective crankshafts 14 are rotated in one direction by the torque transmitted to the transmission gear 85, the respective eccentric portions 72 and 73 of the crankshafts 14 are eccentrically rotated about the axis O2. Accordingly, the oscillating gears 12 and 13 rotate about the axis O1 while oscillating in the housing 5 in accordance with the rotation of the eccentric portions 72 and 73. As a result, the external teeth 12a and 13a of the oscillating gears 12 and 13 rotate while passing over the internal gear pins 26, for example, one by one. The carrier 11 rotates about the 1 st axis O1 in accordance with the rotation of the swing gears 12 and 13. As a result, the rotation of the crankshaft 14 is decelerated and output as the rotation of the carrier 11.

Here, as described above, a lubricant is sealed in the housing 5 for the purpose of lubrication of the speed reducing mechanism portion 6 and the like. The lubricant moves in the housing 5 by the operation of the speed reducing mechanism portion 6 (for example, rotation of the speed reducing mechanism portion 6 itself, reduction in viscosity by heat generated in the speed reducing mechanism portion 6, or the like). In the present embodiment, the housing space S is sealed by the seal ring 55 interposed between the housing 5 and the 2 nd module 42 and the seal ring 123 interposed between the housing 5 and the input shaft 7. This can suppress leakage of the lubricant from the housing 5.

In particular, the present embodiment has a structure in which: the bearing 115 is disposed on the opposite side (atmosphere side) of the seal ring 123 from the housing space S in the through hole 57 of the housing 5.

With this structure, the bearing 115 can be prevented from blocking the flow of the lubricant in the housing 5. Therefore, the lubricant can be efficiently made to reach the seal ring 123. As a result, the seal ring 123 can be prevented from becoming high in temperature due to frictional heat or the like generated between the seal ring and the input shaft 7. In this case, for example, thermal deformation of the seal ring 123 can be suppressed, and the sealing performance can be maintained for a long period of time.

In the present embodiment, the structure is such that: the seal ring is not disposed on the opposite side of the bearing 115 from the housing space S.

With this configuration, the lubricant can be efficiently supplied to all the seal rings 55 and 123 included in the reduction gear 1.

However, in the conventional structure in which the seal member is disposed outside the housing with respect to the bearing, if it is necessary to take out the input shaft from the speed reducer, it is necessary to take out the seal member before the input shaft. In this case, the case may be damaged by inserting a jig or the like between the through hole and the sealing member during removal of the sealing member.

Here, a method of attaching and detaching the input shaft 7 of the speed reducer 1 according to the present embodiment will be described.

First, after the motor is removed, a tool or the like is inserted into the through hole 57 from the 1 st side in the axial direction. Then, the retainer 117 is contracted and deformed, and the retainer 117 is removed from the housing 5. This allows the bearing 115 to move to the 1 st side in the axial direction with respect to the housing 5.

Next, the input shaft 7 is pulled out from the housing 5, whereby the entire input shaft 7 is taken out from the housing 5 together with the bearing 115. That is, the input shaft 7 is taken out from the housing 5 in a state separated from the seal ring 123. This allows the retainer ring 119 to be removed to replace the bearing 115 or the seal ring 123 in the through hole 57.

When the input shaft 7 is mounted to the housing 5 again, the bearing 115 is first mounted to the input shaft 7. Specifically, the enlarged portion 110 is inserted into the inner ring 115b, and then the retainer ring 119 is attached to the enlarged portion 110. Next, the input shaft 7 is inserted into the through hole 57 together with the bearing 115. At this time, the input shaft 7 is inserted until the outer ring 115a abuts against the 1 st step surface 37a, whereby the input gear 131 meshes with the transmission gear 85. After that, the retainer 117 is fitted into the through hole 57, and the input shaft 7 is completely fitted.

As described above, in the present embodiment, the input shaft 7 is configured to be detachable from the housing 5 in a state separated from the seal ring 123.

With this configuration, when the input shaft 7 is taken out from the housing 5, the seal ring 123 does not need to be taken out. Therefore, the possibility of a tool or the like coming into contact with the inner peripheral surface of the through hole 57 can be reduced. Therefore, damage to the case 5 can be suppressed. Further, maintenance can be improved as compared with a case where work is performed while there is a concern that the tool and the housing 5 come into contact with each other.

In the present embodiment, the inner diameter of the seal ring 123 is smaller than the inner diameter of the bearing 115.

Therefore, when the input shaft 7 is removed, the contact portion (the enlarged portion 110) of the input shaft 7 that is in close contact with the seal ring 123, the bearing 115, and the housing 5 can be prevented from contacting.

In the present embodiment, the speed reduction mechanism 6 is provided in the housing space S.

With this configuration, since the leakage of the lubricant from the housing 5 can be suppressed as described above, the lubrication performance of the speed reduction mechanism portion 6 can be maintained for a long period of time.

In the present embodiment, the outer diameter of the input gear 131 is smaller than the inner diameter of the seal ring 123.

With this structure, the input gear 131 and the seal ring 123 can be suppressed from coming into contact when the input shaft 7 is removed. As a result, the maintainability can be further improved.

In the present embodiment, the structure is such that: a retainer 117 is detachably provided to the housing 5, and the retainer 117 regulates movement of the bearing 115 in a direction away from the seal ring 123 (the 1 st side in the axial direction).

With this configuration, when the input shaft 7 is removed, the input shaft 7 can be removed integrally with the bearing 115 simply by removing the retainer ring 117 from the housing 5. This can achieve further improvement in maintainability.

In embodiment 1, the description has been given of the structure in which the bearing 115 is integrally taken out with the input shaft 7, but the structure is not limited to this. That is, the input shaft 7 and the bearing 115 may be separately removed. In this case, the dimensions of the bearing 115, the seal ring 123, and the input gear 131 can be appropriately changed. The input shaft 7 may not be removable (a configuration not assuming removal).

In the above-described embodiment, the structure in which the bearing 115 is disposed on the atmosphere side with respect to the seal ring 123 has been described, but the structure is not limited to this structure. The seal ring 123 of the speed reducer 1 may be disposed on the side of the housing space S with respect to the bearing 115.

In the above-described embodiment, the configuration in which the input shaft 7 is divided into the plurality of members (the outer shaft 100, the inner shaft 101, and the gear shaft 102) has been described, but the configuration is not limited to this configuration. The input shaft 7 may also be integrally formed.

In the above-described embodiment, the structure in which the bearing 115 is inserted into the through hole 36 has been described, but the structure is not limited to this structure. The bearing 115 may be fixed to the housing 5 by press fitting or the like.

(embodiment 2)

Next, embodiment 2 of the present invention will be explained. Fig. 3 is a sectional view of the reduction gear 200 of embodiment 2. In the present embodiment, the input shaft 230 penetrates the speed reduction mechanism unit 6 in the axial direction, which is different from the above-described embodiment 1.

In the reduction gear 200 shown in fig. 3, the 2 nd case 22 of the case 5 is formed in a bottomed tubular shape having a 2 nd opening toward the axial direction. The 2 nd housing 22 is formed with a flange portion 210 protruding radially outward from the peripheral wall 31. The flange portion 210 is fixed to the cylindrical portion 21a of the 1 st housing 21 in a state of being in contact with the cylindrical portion 21a in the axial direction.

The through hole 36 of embodiment 1 is not formed in the bottom wall 32 of the 2 nd case 22. Therefore, the 2 nd housing 22 closes the entire opening of the 1 st housing 21 from the 1 st side in the axial direction.

In the present embodiment, the inner diameter of the 2 nd through hole 57 gradually decreases toward the 2 nd side in the axial direction. Specifically, the 2 nd through hole 57 has a large diameter portion 220, a medium diameter portion 221, and a small diameter portion 222. The large diameter portion 220 and the middle diameter portion 221 are connected by a stepped surface 220 a. In the 2 nd module (base) 42, a recess 225 is formed around the 2 nd through hole 57. The recess 225 has a larger inner diameter than the large diameter portion 220 and is open to the 2 nd side in the axial direction. When the motor is coupled to the decelerator 200, a part of the housing in the motor is fitted into the concave portion 225. The 2 nd through hole 57 is opened in the bottom surface of the recess 225.

A seal ring 235 is fitted into the small diameter portion 222 of the 2 nd through hole 57.

A bearing 236 is inserted into the large diameter portion 220. The outer race 236a of the bearing 236 is held between the step surface 220a of the 2 nd through hole 57 and the retainer ring 237, and the retainer ring 237 is held by the large diameter portion 220. That is, the bearing 236 is disposed on the atmosphere side with respect to the seal ring 235. Retaining ring 237 is held in groove 223, and groove 223 is formed in the inner peripheral surface of large diameter portion 220. The inner diameter of the bearing 236 (inner diameter of the inner race 236b) is larger than the inner diameter of the seal ring 235 and smaller than the inner diameter of the small diameter portion 222 of the 2 nd through hole 57.

The input shaft 230 transmits the driving torque of the motor to the transmission gear 85. The input shaft 230 passes through the carrier 11 and the swing gears 12 and 13 through the 2 nd through hole 57, the 2 nd through hole 63, the 1 st through hole 62, and the 1 st through hole 44. Specifically, the input shaft 230 is a structure in which the coupling shaft 231 and the gear shaft 232 are axially assembled.

The coupling shaft 231 is a hollow circular shaft extending along the axis O1. A motor is coupled to the coupling shaft 231 from the 2 nd side in the axial direction. The outer diameter of the coupling shaft 231 is gradually reduced toward the 1 st side in the axial direction. Specifically, the coupling shaft 231 includes a large diameter portion 240, a medium diameter portion 241, and a small diameter portion 242. The large diameter portion 240 and the middle diameter portion 241 are connected by a stepped surface 240 a. The outer diameter of the large diameter portion 240 of the connecting shaft 231 is smaller than the inner diameter of the intermediate diameter portion 221 of the 2 nd through hole 57 and larger than the inner diameter of the seal ring 235. The small diameter portion 242 of the connecting shaft 231 has an outer diameter sufficiently smaller than the inner diameter of the center holes 62, 63 of the oscillating gears 12, 13. Thereby, interference between the oscillating gears 12, 13 and the input shaft 230 is suppressed.

The coupling shaft 231 is inserted into the 2 nd through hole 57 from the 2 nd side in the axial direction. In this state, the small diameter portion 242 passes through the inside of the seal ring 235 and is positioned in the center holes 62, 63. The outer peripheral surface of the small diameter portion 242 is in close contact with the seal ring 235. This blocks the connection between the inside and the outside of the housing 5 via the 2 nd through hole 57. Further, the intermediate diameter portion 221 is inserted inside the bearing 236 (inner race 236 b). The bearing 236 is held between the step surface 240a of the coupling shaft 231 and the retainer ring 250, and the retainer ring 250 is held by the intermediate diameter portion 241. The retainer ring 250 is held by a groove 251, and the groove 251 is formed in the intermediate diameter portion 241.

The gear shaft 232 has a fixing portion 255, an extension portion 256, and an input gear 257.

The fixing portion 255 is fixed to the small diameter portion 242 of the connecting shaft 231 by press fitting or the like. The extension 256 penetrates the 1 st center hole 62 of the 1 st swing gear 12 and the 1 st through hole 41a of the 1 st block 41. The input gear 257 protrudes from the extension portion 256 toward the 1 st side in the axial direction. The input gear 257 meshes with the transmission gear 85 inside the housing 5. The maximum outer diameter of the input gear 257 is smaller than the inner diameter of the seal ring 123.

In the present embodiment, when the input shaft 230 is removed, the retainer 237 is removed from the 2 nd through hole 57, and then the input shaft 230 is pulled out. Thus, the input shaft 230 is taken out from the reduction gear 1 together with the bearing 236.

The present embodiment also provides the same operational advantages as embodiment 1.

(embodiment 3)

Next, embodiment 3 of the present invention will be described. Fig. 4 is a sectional view of the reduction gear 300 of embodiment 3. In the present embodiment, the difference from the above embodiments is that the input shaft 340 is arranged parallel to (offset from) the axis O1.

In the reduction gear 300 shown in fig. 4, a support cylinder 310 is formed on the bottom wall 32 of the 2 nd housing 22. The support cylinder 310 protrudes from the outer peripheral portion of the bottom wall 32 to the 1 st side in the axial direction. The axis O5 of the support cylinder 310 is arranged parallel to the axis O1. The support tube 310 has a through hole 311 formed therein to connect the inside and the outside of the housing 5.

The inner diameter of the support cylinder 310 gradually increases toward the 1 st side in the axial direction. Specifically, the large diameter portion 320, the intermediate diameter portion 321, and the small diameter portion 322 of the support cylinder 310 are axially connected.

When the motor is coupled to the decelerator 300, a portion of the housing 331 of the motor 330 is embedded in the large diameter portion 320. The output shaft 332 of the motor 330 is located inside the middle diameter portion 321 through the large diameter portion 320.

The input shaft 340 has: a coupling portion 341 coupled to the output shaft 332; and an input gear 342 protruding from the coupling portion 341 to the 2 nd side in the axial direction.

The bearing 345 is interposed between the 1 st end portion and the intermediate diameter portion 321 in the axial direction in the coupling portion 341. Thereby, the input shaft 340 is rotatably supported by the housing 5 via the bearing 345. The bearing 345 is positioned in the axial direction between a retaining ring 346 detachably attached to the inner peripheral surface of the intermediate diameter portion 341 and a boundary surface between the same small diameter portion 322 of the intermediate diameter portion 341.

The seal ring 347 is interposed between the 2 nd end (the housing space S side with respect to the bearing 345) of the coupling portion 341 in the axial direction and the small diameter portion 322. The seal ring 347 is in close contact with the outer peripheral surface of the coupling portion 341 and the inner peripheral surface of the small-diameter portion 322 to block the connection between the inside and the outside of the housing 5 via the through hole 311.

The reduction mechanism portion 6 of the present embodiment includes an intermediate gear 350 that connects the transmission gear 85 and the input gear 342. The intermediate gear 350 is disposed between the bottom wall 32 and the 1 st block 41 in the 2 nd housing 22. The intermediate gear 350 is a secondary gear having a 1 st gear 351 and a 2 nd gear 352. The 1 st gear 351 and the 2 nd gear 352 are fixed by, for example, a screw 355 in a state of coaxially overlapping the axis O1. The intermediate gear 350 is fixed to a support shaft 360. The support shaft 360 extends coaxially with the axis O1 and axially penetrates the intermediate gear 350. The support shaft 360 is rotatably supported by the 1 st block 41 and the bottom wall 32.

The 1 st gear 351 has a larger outer diameter than the 2 nd gear 352. The 1 st gear 351 meshes with the input gear 342 of the input shaft 340. The 2 nd gear 352 meshes with the transmission gear 85.

The present embodiment can also provide the same operational advantages as those of the above-described embodiments.

(other modification example)

The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Addition, omission, replacement, and other changes in configuration may be made within the scope not departing from the spirit of the present invention. The invention is not to be limited by the foregoing description, but is only limited by the scope of the appended claims.

In the above-described embodiment, the configuration in which the input shaft 7 transmits the driving torque of the motor to, for example, the speed reduction mechanism unit 6 has been described as an example of the shaft holding mechanism, but the present invention is not limited to this configuration. The shaft may be connected to a portion other than the reduction mechanism portion 6.

In the above embodiment, the case where the shaft is used as the input shaft has been described, but the present invention is not limited to this configuration. The shaft may also be an output shaft.

In addition, the components of the above embodiments may be replaced with known components as appropriate without departing from the scope of the present invention, and the above modifications may be combined as appropriate.