Hydraulic motor with reducer

Abstract

To provide a hydraulic motor having a reduction gear for preventing a load operating on a bearing from becoming excessive even if a carrier of a planetary gear is tilted and for preventing a bearing life from becoming short.SOLUTION: A hydraulic motor having a reduction gear includes: a carrier (second carrier 54) of a planetary gear spline-connected to a motor casing 13; bearings 18, 19 for rotatably supporting a rotary drum 16 relative to the motor casing; and a collar 96 and a spacer 97 for applying a preload to a bearing by abutting on a side face of the bearing. The collar 96 is disposed in a side of the carrier (second carrier 54) relative to the bearings 18, 19, and the spacer 97 is disposed in a side opposite to the carrier (second carrier 54) relative to the bearings 18, 19. The carrier 54 has an annular part 54a that projects so as to prevent omission of the collar 96, and a recess 54b for forming a predetermined gap between the collar and itself within the annular part.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a hydraulic motor with a speed reducer, and more particularly to a hydraulic motor with a speed reducer aiming at stabilizing the life of the speed reducer having bearings used with appropriate preloading.

Background Art

[0002] Conventionally, in a hydraulic motor with a speed reducer such as a power shovel car, there is one that uses a swash plate type piston motor as a drive source to rotate a rotary drum (casing of the speed reducer) to transmit a driving force. As the speed reducer, a planetary gear mechanism with a large reduction ratio is used. In the planetary gear mechanism, the sun gear is attached to the shaft of the hydraulic motor (drive shaft), the rotary drum has an internal gear (driven shaft), and the carrier of the planetary gear is fixed to the motor casing (fixed shaft). Since a large torque is applied between the carrier of the planetary gear and the motor casing, a spline coupling (spline engagement) is used.

[0003] Angular ball bearings or tapered roller bearings are used in a back-to-back combination for the bearings arranged between the motor casing and the rotary drum. And a preload adjustment mechanism is provided to apply a preload to the bearings. The preload adjustment mechanism is composed of a spacer for adjusting the magnitude of the preload (adjusting the preload by thickness) and a lock washer mechanism for fixing the bearing and the spacer together.

[0004] For example, in the hydraulic motor with a speed reducer described in Patent Document 1, the second carrier 29 is in contact with the lock washer mechanism 32 (see FIG. 3 of Patent Document 1). The lock washer mechanism 32 is in contact with a spacer (no number), and the spacer is in contact with the inner ring end face of the bearing 22b. The bearings 22a and 22b are angular ball bearings, and generally, since angular ball bearings are used with appropriate preloading, it is considered that a preload is applied by adjusting the thickness of the spacer.

[0005] Further, for example, in the hydraulic traveling motor with a speed reducer described in Patent Document 2, a spacer 97 is disposed between the bearing 18a and the collar 96 to apply preload (see FIG. 2 of Patent Document 2). The gap between the second carrier 54 and the spacer 97 is slight, and the gap between the second carrier 54 and the collar 96 is also slight. The second carrier 54 is spline-coupled to the motor casing 13 by a spline 22.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the hydraulic motor with a speed reducer described in Patent Document 1, when the second carrier 29 transmits the rotation and torque of the second planetary gear 28, it slightly tilts due to elastic deformation, and a load in the horizontal direction (thrust load) acts on the rotation axis. The thrust load acts on the inner ring of the bearing 22b via the second carrier 29, the lock washer 33, and the spacer. For a bearing with an appropriate preload, when a load due to the thrust load is added, the load acting on the bearing becomes excessive, leading to a problem of a reduction in bearing life.

[0008] In the hydraulic traveling motor with a speed reducer described in Patent Document 2, generally there is a gap (play) in the spline coupling part. When a thrust load acts as in Patent Document 1, the second carrier 5 may tilt with respect to the speed reducer rotating shaft. Then, the second carrier 54 comes into contact with the spacer 97 or the collar 96, and a thrust load acts on the inner ring of the bearing through these. Therefore, also in this case, a load due to the thrust load is added to the bearing to which an appropriate preload is applied, resulting in an excessive load acting on the bearing and leading to a problem of a reduction in bearing life.

[0009] Therefore, an object of the present invention is to provide a hydraulic motor with a speed reducer in which the load acting on the bearing does not become excessive even when the carrier of the planetary gear tilts, and there is no risk of a reduction in bearing life.

Means for Solving the Problems

[0010] A typical configuration of the hydraulic motor with a speed reducer according to the present invention includes a motor casing incorporating a hydraulic motor, a rotating drum rotatably supported by the motor casing and having a planetary gear speed reduction mechanism, a carrier of the planetary gear spline-coupled to the motor casing, a bearing rotatably supporting the rotating drum with respect to the motor casing, and a collar and a spacer that abut against the side surface of the bearing to apply preload to the bearing. The collar is disposed on the carrier side with respect to the bearing, and the spacer is disposed on the side opposite to the carrier with respect to the bearing. The carrier has an annular portion protruding to prevent the collar from falling off, and a recess inside the annular portion that forms a predetermined gap with the collar.

Effects of the Invention

[0011] According to the present invention, it is possible to provide a hydraulic motor with a speed reducer in which the load acting on the bearing does not become excessive even when the carrier of the planetary gear tilts, and there is no risk of a reduction in bearing life.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0013] Regarding the hydraulic motor 10 with a speed reducer of the present invention, preferred embodiments will be given and described in detail with reference to the accompanying drawings.

[0014] As shown in FIG. 1, the hydraulic motor 10 with a speed reducer is generally composed of a hydraulic motor 11 and a speed reducer 14. When the output shaft 24 of the hydraulic motor 11 rotates, the rotating drum 16 which is the exterior of the speed reducer 14 rotates.

[0015] The hydraulic motor 11 is composed of a piping port 12, a motor casing 13, an output shaft 24, and a cylinder block, a piston, a variable displacement mechanism, etc. (not shown). The hydraulic motor 11 rotates the output shaft 24 by the pressure oil supplied or discharged through the piping port 12 from a hydraulic pump (not shown), and changes the rotational speed of the output shaft 24 by the variable displacement mechanism.

[0016] The motor casing 13 forms the outer shell of the hydraulic motor 11. A fixed flange 34 is formed on the outer peripheral surface 38 of the motor casing 13, and the fixed flange 34 is fixed to the frame of a construction vehicle (not shown) such as a crawler hydraulic excavator using bolts or the like.

[0017] On one end surface 37 (the left end surface in FIG. 1) of the motor casing 13, a plurality of protrusions 21 that abut against the second carrier 54 are formed. Further, a spline 22 is formed on the outer peripheral surface 38 behind the protrusions 21 (the right side in FIG. 1) of the motor casing 13. Similarly, a spline 22 is also formed inside the second carrier 54 described later, and these are meshed with each other to be combined in a non-rotatable manner.

[0018] The speed reducer 14 is roughly composed of a rotating drum 16, an output shaft 24, and planetary gear speed reduction mechanisms 48 and 49.

[0019] The rotating drum 16 forms the outer shell of the speed reducer 14. A drive flange 35 is formed on the outer peripheral surface of the rotating drum 16. The drive flange 35 is fixed to a sprocket that drives a crawler belt of a construction vehicle (not shown) using bolts or the like, and drives a construction vehicle such as a hydraulic excavator. Further, a speed reducer internal gear 52 is formed on the inside of the rotating drum 16 over the entire circumference.

[0020] The rotating drum 16 is rotatably supported by bearings 18 and 19 with respect to the motor casing 13. The bearings 18 and 19 are fitted to a stepped portion 38a whose diameter becomes thinner from the outer peripheral surface 38 of the motor casing 13. Also, a mechanical seal 20 is disposed at the joint between the rotating drum 16 and the motor casing 13.

[0021] The speed reducer chamber 51 is a region surrounded by the rotating drum 16, a cover 17 that covers the rotating drum 16, and the motor casing 13. And the planetary gear speed reduction mechanisms 48 and 49 are housed in the speed reducer chamber 51.

[0022] The planetary gear speed reduction mechanism 48 is disposed in the first stage (the left side in FIG. 1) in the speed reducer chamber 51, and includes a first sun gear 56 that is coupled to the output shaft 24 of the hydraulic motor 11 and rotates integrally therewith, a plurality of first planetary gears 58 that mesh with the first sun gear 56 and the speed reducer internal gear 52 and rotate and revolve, and a first carrier 53 that rotatably supports the first planetary gears 58. A carrier internal gear 55 is formed on the first carrier 53 and meshes with the second sun gear 57.

[0023] The planetary gear reduction mechanism 49 is arranged in the second stage (the right side in FIG. 1) within the reduction gear chamber 51, and is composed of a second sun gear 57 meshing with the internal gear 55 within the carrier, a plurality of second planetary gears 59 meshing with the second sun gear 57 and the internal gear 52 within the reduction gear, and a second carrier 54 rotatably supporting the second planetary gears 59. One end side in the axial direction (the right side in FIG. 1) of the second carrier 54 is spline-coupled to the motor casing 13 by a spline 22 and does not rotate. Therefore, the second planetary gears 59 rotate on their own axes but do not revolve. Since the second planetary gears 59 and the internal gear 52 within the reduction gear are meshed, the rotating drum 16 integrated with the internal gear 52 within the reduction gear rotates when the second planetary gears 59 rotate on their own axes. With these configurations, when the output shaft 24 rotates, the rotating drum 16 can be rotated with a large reduction ratio.

[0024] FIG. 2 is an enlarged detailed view of the portion surrounded by the dotted line II shown in FIG. 1. As shown in FIG. 2, bearings 18 and 19 are fitted into the stepped portion 38a of the motor casing 13. A groove 95 is formed on the outer peripheral surface 38 on the side of the second carrier 54 (the left side in FIGS. 1 and 2) of the stepped portion 38a. A collar 96 formed by dividing a ring into three parts is inserted into the groove 95.

[0025] An annular portion 54a for preventing the collar 96 from falling off is formed at one end side in the axial direction (the right side in FIG. 1) of the second carrier 54. The annular portion 54a is cylindrical, protrudes from the second carrier 54 beyond the spline 22, and extends so as to cover at least a part of the outer peripheral surface of the collar 96.

[0026] Inside the annular portion 54a of the second carrier 54, a recess 54b is formed so that when the second carrier 54 and the protrusion 21 of the motor casing 13 come into contact, a predetermined gap 98 is formed between the second carrier 54 and the collar 96. The predetermined gap 98 means that even in a state where the second carrier 54 is tilted (FIG. 3) as described later, the second carrier 54 is collar 96 on the side of does not contact spaced and the gap is maintained.

[0027] As a feature of the present invention, the spacer 97 is disposed on the opposite side (the right side in FIGS. 1 and 2) of the second carrier 54 with respect to the bearings 18 and 19. The spacer 97 is an annular thin plate and abuts against the corner 38b of the stepped portion 38a. Since the inner rings 18a and 19a of the bearings 18 and 19 are sandwiched and fixed by the collar 96 and the spacer 97, appropriate preload can be applied to the bearings 18 and 19 by adjusting the thickness of the spacer 97.

[0028] FIG. 3 is a diagram for explaining the state in which the second carrier 54 is tilted. As described in the background art section, the second carrier 54 is slightly tilted by elastic deformation when transmitting the rotation and torque of the second planetary gear 59, and a load in the horizontal direction (thrust load) acts on the rotation axis. Generally, since there is a gap (play) in the spline coupling portion, when a thrust load acts, the second carrier 54 may tilt with respect to the output shaft 24 as shown in FIG. 3.

[0029] However, in the present invention, the spacer 97 is disposed on the opposite side (the right side in FIGS. 1 and 2) of the second carrier 54 with respect to the bearings 18 and 19. As a result, even when the second carrier 54 is tilted, the annular portion 54a at its tip does not contact the "spacer 97 and the collar 96". If the tilted annular portion 54a were to contact, it would mean contacting the bearing 18. Although the inner ring 18a of the bearing 18 abuts (is adjacent) against the collar 96, the outer ring 18b is recessed further than the collar 96. And when the annular portion 54a tilts, it approaches the bearing 18 as it approaches the outer periphery. Therefore, the fact that the outer ring 18b is recessed can extremely reduce the possibility of the annular portion 54a contacting the bearing 18.

[0030] As described above, according to the present invention, even when the second carrier 54 is tilted, no additional load due to the thrust load is added to the bearings 18 and 19 to which an appropriate preload is applied. Therefore, it is possible to provide a hydraulic motor with a speed reducer in which there is no risk of a decrease in bearing life due to the tilt of the second carrier 54.

[0031] The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. Needless to say, the present invention is not limited to such examples. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and it is naturally understood that they also belong to the technical scope of the present invention.

Industrial Applicability

[0032] The present invention can be used as a hydraulic motor with a speed reducer aiming at stabilizing the life of a speed reducer having a bearing used with appropriate preload.

Explanation of Signs

[0033] 10... Hydraulic motor with speed reducer, 11... Hydraulic motor, 12... Pipe port, 13... Motor casing, 14... Speed reducer, 16... Rotating drum, 17... Cover, 18... Bearing, 18a... Inner ring, 18b... Outer ring, 19... Bearing, 19a... Inner ring, 20... Mechanical seal, 21... Protrusion, 22... Spline, 24... Output shaft, 33... Snap ring, 34... Fixed flange, 35... Driving flange, 37... One end face, 38... Outer peripheral surface, 38a... Step portion, 38b... Corner portion, 41... Sun gear group, 48... Planetary gear reduction mechanism, 49... Planetary gear reduction mechanism, 51... Speed reducer chamber, 52... Internal gear of speed reducer, 53... First carrier, 54... Second carrier, 54a... Annular portion, 54b... Concave portion, 55... Internal gear in carrier, 56... First sun gear, 57... Second sun gear, 58... First planetary gear, 59... Second planetary gear, 72... First bearing, 95... Groove, 96... Collar, 97... Spacer, 98... Gap

Claims

【Claim 1】 A motor casing incorporating a hydraulic motor, a rotary drum rotatably supported by the motor casing and having a planetary gear reduction mechanism, a carrier of a planetary gear spline-coupled to the motor casing, a protrusion provided on the motor casing and abutting against the carrier, a bearing rotatably supporting the rotary drum with respect to the motor casing, a collar and a spacer that abut against a side surface of the bearing to apply preload to the bearing, the collar being disposed on the carrier side of the bearing, the spacer being disposed on the side opposite to the carrier of the bearing, the carrier having an annular portion protruding to prevent the collar from falling off and a recess inside the annular portion to form a predetermined gap with the collar, the gap being an interval at which the carrier does not contact the side surface of the collar when the protrusion contacts the carrier, characterized by a hydraulic motor with a reduction gear.

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