JPH09184472A - Forced lubrication structure of bearing of hydraulic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To forcibly lubricate a bearing of a hydraulic motor to extend its span of life. SOLUTION: A spiral groove 19 is formed on an outer peripheral part of an axis 2 of rotation of a hydraulic motor 1 facing an inner peripheral part 18 of a through hole 17 of a valve plate 12. An end surface of a rear bearing 14 axially supporting the axis 2 of rotation communicates with the neighbourhood of an outer peripheral part 16 of the valve plate 12. Working oil is respectively leaked in the circumference of the spiral groove 19 on the inner peripheral side and in the neighbourhood of an opening part of an oil passage 15 on the outer peripheral side from between the valve plate 12 and an end surface of a cylinder block 4. Even when the axis 2 of rotation is rotated in either one direction, working oil leaked on the inner peripheral side or working oil leaked on the outer peripheral side flows in the oil passage 15 and the rear bearing 14, and it is possible to fircibly lubricate the rear bearing 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for forcibly lubricating a rotary shaft of a hydraulic motor such as a swash plate type or an oblique shaft type.

[0002]

2. Description of the Related Art Conventionally, a bearing of a rotary shaft of a hydraulic rotary device such as a hydraulic motor or a hydraulic pump is lubricated by using hydraulic oil leaking around the rotary shaft. In hydraulic rotating equipment, hydraulic oil is supplied and discharged through a valve plate that communicates with a stationary oil passage, and hydraulic oil flows into and out of the bore of a cylinder block that rotates and slides on the surface of the valve plate. Done. The hydraulic oil leaks from the sliding surface due to a slight gap in the sliding surface or the pressure of the hydraulic oil. In general, the bearings that support the rotating shaft are lubricated by natural circulation of the hydraulic oil that has leaked to the rotating shaft.

Prior art relating to forcibly lubricating a bearing is disclosed in, for example, Japanese Patent Application Laid-Open No. 58-206888 and Japanese Patent Application Laid-Open No. 2-161176. JP-A-58-
In the prior art of 206888, the bearing provided on the swash plate side of the swash plate type piston motor or pump is provided in the portion where the rotary shaft is extracted to the outside of the casing. The blade is provided to form an oil passage communicating from the outside to the inside of the bearing, and the working oil is circulated to forcibly lubricate the bearing. In the prior art of Japanese Patent Application Laid-Open No. Hei 2-161176, in order to forcibly lubricate the bearings provided on the outer sides of the swash plate side and the valve plate side of the cylinder block of the swash plate type axial piston pump, the respective bearings are configured as sliding bearings and are rotated. By forming a spiral groove in the side opposite to the rotation direction and forming an oil passage in the rotary shaft that communicates between both ends of the portion where the spiral groove is formed, the working oil is circulated in accordance with the rotation of the rotary shaft. The bearing part can be forcibly lubricated.

[0004]

In a hydraulic rotary device, when the bearing is lubricated by the flow of hydraulic oil by natural circulation, it is difficult to replace the hydraulic oil, and the oil temperature rises and the oil deteriorates. There is a possibility that dust will be generated, resulting in damage to the bearing such as flaking, which will shorten the service life. In particular, when the rotary shaft is used in the direction close to vertical as a revolving structure drive for hydraulic excavators and hydraulic cranes, the output shaft is mounted downward, so the swash plate hydraulic motor has a bearing on the valve plate side that is the upper side. Is insufficiently lubricated.

The prior art of Japanese Patent Laid-Open No. 58-206888 discloses the forced lubrication of the bearing on the swash plate side for taking out the output shaft. Regarding the forced lubrication of the bearing on the valve plate side, the prior art discloses a valve plate as prior art. From the end of the bearing on the side of the bearing to the end of the bearing on the side of the swash plate, an oil passage is provided at the center of the rotary shaft, and an oil passage extending in the radial direction that opens on the outer peripheral surface at the end of the bearing on the side of the swash plate is provided. The configuration for circulating the entire working oil by utilizing the centrifugal force in the oil passage extending in the radial direction is described. Circulation of the hydraulic oil is performed by the centrifugal force that acts on the radial oil passage provided on the swash plate side, so it is necessary to increase the diameter of this passage in order to increase the amount of passage through the valve plate side bearing portion. There is a problem with the strength of the rotating shaft. Therefore, the cooling capacity of the valve plate side bearing part that receives a high load,
The lubrication ability cannot be improved. In addition, Japanese Unexamined Patent Publication
A configuration in which the bearing of the rotating shaft is configured as a sliding bearing and a spiral groove is provided on the rotating side as in the prior art of 161176 is applicable to a pump in which the rotating direction is one direction, but the rotating direction is It cannot be applied to motors that need to be switchable. That is, if the spiral groove rotates in one direction, it is possible to send the working oil to the tip side of the bearing on the valve plate side, but when rotating the rotating shaft in the other direction, the oil to the sump on the tip side of the rotating oil Is no longer supplied, and the valve plate side bearing cannot be lubricated. Further, since it is necessary to form the bearing as a sliding bearing, the frictional resistance becomes larger than that in the case of a rolling bearing, and the starting characteristics of the rotating shaft deteriorate.

An object of the present invention is to provide a hydraulic motor forced lubrication structure capable of sufficiently lubricating the valve plate side of the hydraulic motor.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to bearing forcing to lubricate a bearing of a rotary shaft that penetrates a valve plate in a valve casing that covers the valve plate side of a cylinder block provided in a hydraulic motor. The lubrication structure is provided on the outer peripheral portion of the rotary shaft facing the inner peripheral portion of the through hole provided in the valve plate, and the rotation of the rotary shaft is used for the axial direction with respect to the hydraulic oil existing near the through hole. A fluidizing means for causing the fluid to flow in the valve casing, and the valve casing is provided with an oil passage that connects the other end of the bearing facing the valve plate at one end in the axial direction and the vicinity of the outer periphery of the valve plate. It is a bearing forced lubrication structure of the hydraulic motor. According to the present invention, fluidizing means is provided on the outer peripheral portion of the rotary shaft, and the working oil existing near the through hole is fluidized in the axial direction by utilizing the rotation of the rotary shaft. The valve casing that covers the valve plate is provided with an oil passage that connects the other end side of the bearing facing the valve plate at one end side in the axial direction and the vicinity of the outer peripheral portion of the valve plate. At the inner and outer peripheral portions of the valve plate, hydraulic oil leaks from between the fixed valve plate and the rotating and sliding cylinder block, is fluidized by the fluidizing means, and passes through an oil passage provided in the valve casing. The bearings are forced to be lubricated as they circulate.

Further, in the invention, the fluidizing means is a spiral groove formed on the outer peripheral portion of the rotating shaft.
According to the present invention, since the spiral groove is formed on the outer peripheral portion of the rotary shaft, the surrounding hydraulic oil can be made to flow in one or the other axial direction in accordance with the rotation of the rotary shaft. Since the outer peripheral side of the valve plate and the other end side of the bearing communicate with each other through an oil passage,
Regardless of the direction in which the hydraulic oil flows in the axial direction, the hydraulic oil leaking from the outer peripheral side or the inner peripheral side of the valve plate can be made to flow through the bearings for forced lubrication.

Further, in the invention, the fluidizing means is a blade attached to an outer peripheral portion of the rotating shaft. According to the present invention, since the fluidizing means is formed by mounting the blades on the outer peripheral portion of the rotary shaft, it is possible to efficiently fluidize the hydraulic oil without affecting the strength of the rotary shaft and the like.

[0010]

1 shows the configuration of a hydraulic motor 1 according to an embodiment of the present invention. The hydraulic motor 1 is of a swash plate type, and the rotary shaft 2 is inserted into a cylinder block 4 via a spline coupling portion 3. Cylinder block 4
A bore 6 into which a plurality of pistons 5 are inserted is formed inside. The piston 5 can reciprocate parallel to the axial direction of the rotary shaft 2. The shoe 7 is attached to one end of the piston 5.
Are connected via spherical bearings. The shoe 7 abuts on the surface of the swash plate 8 and can be slidably displaced when the rotary shaft 2 rotates with the rotation of the cylinder block 4. The swash plate 8
It is fixed to the casing 9 of the hydraulic motor 1 so as to be inclined with respect to the axis of the rotary shaft 2. The rotating shaft 2 is a swash plate 8
Through and through to the outside of the casing 9 to serve as an output shaft. Between the rotary shaft 2 on the output side and the casing 9,
A front bearing 10 that is a rolling bearing and a seal portion 11 that prevents leakage of hydraulic oil are provided.

The rotary shaft 2 is rotatably supported by the front bearing 10 on one side and penetrates the valve plate 12 on the other side.
It is pivotally supported by a rear bearing 14 housed in the valve casing 13. The valve casing 13 is attached to the casing 9 so that the surface on one side covers the surface on the other side of the valve plate 12 on which the cylinder block 4 rotates and slides. In the valve casing 13, an oil passage (not shown) for supplying and discharging hydraulic oil to and from the bore 6 in the cylinder block 4 via a valve hole provided in the valve plate 12 is provided. The end surface of the cylinder block 4 that rotates and slides on the surface of the fixed valve plate 12 has a slight gap, and the hydraulic oil leaks little by little from this gap.
An oil passage 15 is formed in the valve casing 13 so that one end faces the other end of the rear bearing 14, and the other end of the oil passage 15 has the other end.
2 facing the outer peripheral portion 16. A spiral groove 19 is formed on the outer peripheral portion of the rotating shaft 2 facing the inner peripheral portion 18 of the through hole 17 provided on the inner side of the valve plate 12 in the radial direction. Can be flowed to either one of the above. The inner diameter of the through hole 17 is the same as that of the rotary shaft 2.
Make it small so that it is close to the outer diameter of. In FIG. 1, the portion of the rotary shaft 2 where the spiral groove 19 is formed is shown by hatching.

From the gap between the valve plate 12 and the end surface of the cylinder block 4, the hydraulic oil leaks as described above and is fluidized to either one side in the axial direction by the spiral groove 19 which is a fluidizing means. When the spiral groove 19 fluidizes the working oil toward the rear bearing 14, the fluidized working oil is transferred to the rear bearing 1.
4 and flows from the oil passage 15 to the periphery of the outer peripheral portion 16 of the valve plate 12. Around the outer peripheral portion 16 of the valve plate 12, hydraulic oil leaking from between the valve plate 12 and the end surface of the cylinder block 4 also flows, and this hydraulic oil flows between the outer peripheral portion of the cylinder block 4 and the inner peripheral portion of the casing 9. It is discharged to the tank side through the space between. When a flow of hydraulic oil is formed from the rear bearing 14 to the front bearing 10 side by the spiral groove 19, the rear bearing 1
Hydraulic oil leaking to the outer peripheral portion 16 side of the valve plate 12 is supplied to the other end of the rear bearing 4 via the oil passage 15 in the valve casing 13 to the other end of the rear bearing 14. The hydraulic oil fluidized to the front bearing 10 side by the spiral groove 19 is fluidized to the front bearing 10 side through the gap between the inner peripheral side of the cylinder block 4 and the outer peripheral side of the rotary shaft 2, and finally Is discharged from a tank port provided in the casing 9. That is, by processing the spiral groove 19 on the rotating shaft 2, the spiral groove 1
By utilizing the pumping action of No. 9, hydraulic oil can be supplied to the rear bearing 14 for forced lubrication.

FIG. 2 shows a forced lubrication structure for the rear bearing 14 according to another embodiment of the present invention. In this embodiment, parts corresponding to those in the embodiment of FIG. 1 are designated by the same reference numerals, and description thereof will be omitted. In the present embodiment, the inner peripheral portion 18 of the valve plate 20.
Has a through hole 21 that is not as small as the through hole 17 of the valve plate 12 of the embodiment of FIG. 1, and an impeller 22 is mounted on the rotary shaft 2 side. The impeller 22 is a front view in (a) of FIG. 3, and (b).
As shown in the right side view, a spiral blade 23 is formed on the surface, and like the spiral groove 19 of the embodiment of FIG. 1, the surrounding hydraulic oil flows in one or the other axial direction in accordance with the rotation of the rotary shaft 2. Can be made. That is, by mounting the impeller 22 on the rotating shaft 2, the rear bearing 14 can be forcibly lubricated by the pumping action of the impeller 22 as in the embodiment shown in FIG.

As described above, according to each of the embodiments of the present invention, the clearance between the rotary shaft and the valve plate is reduced, and the surrounding hydraulic oil is continuously discharged or sucked toward the rear bearing side as the rotary shaft rotates. Since such a flow is generated, it is possible to generate a flow of the hydraulic oil for the forced lubrication of the rear bearing with the hydraulic oil. This makes it possible to achieve a cooling effect on the rear bearing, prevent deterioration of the hydraulic oil, and remove dust from the rear bearing portion.

[0015]

As described above, according to the present invention, there is provided an oil passage that connects the other end of the bearing, which faces the inner circumference of the valve plate at one end, and the outer circumference of the valve plate, and A circulation path is formed,
Since the fluidizing means causes the hydraulic fluid to flow in the axial direction in accordance with the rotation of the rotary shaft, the hydraulic fluid can be circulated in the path including the bearing. The hydraulic oil leaking from the rotary sliding portion between the valve plate and the cylinder block is constantly supplied to this path, and the bearing can be forcibly lubricated with the hydraulic oil that has not deteriorated.

Further, according to the present invention, since the spiral groove is formed on the rotary shaft as the fluidizing means, it is possible to give the hydraulic oil a flow in the axial direction as the rotary shaft itself rotates.

Further, according to the present invention, since the blades are mounted on the outer peripheral portion of the rotary shaft, it is not necessary to process the rotary shaft to form the blades and the like, and the hydraulic fluid can be efficiently fluidized. .

[Brief description of the drawings]

FIG. 1 is a sectional view of a hydraulic motor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a hydraulic motor according to another embodiment of the present invention.

3 is a front view and a right side view of the impeller 22 of FIG. 2. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic motor 2,30 Rotating shaft 4 Cylinder block 8 Swash plate 9 Casing 10 Front bearing 12,20 Valve plate 13 Valve casing 14 Rear bearing 15 Oil passage 16 Outer peripheral portion 17,21 Through hole 18 Inner peripheral portion 19 Spiral groove 22 Blade car

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[Procedure amendment]

[Submission date] February 20, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for forcibly lubricating a bearing portion of a rotary shaft of a hydraulic motor such as a swash plate type or an oblique type.

Claims (3)

[Claims] 1. A bearing forced lubrication structure for lubricating a bearing of a rotary shaft that penetrates a valve plate in a valve casing that covers an outer side of a valve plate side of a cylinder block provided in a hydraulic motor. Has a fluidizing means provided on the outer peripheral portion of the rotary shaft facing the inner peripheral portion of the through hole provided therein to fluidize the hydraulic oil existing near the through hole in the axial direction by utilizing the rotation of the rotary shaft. However, the valve casing is provided with an oil passage that connects the other end of the bearing, which faces the valve plate at one end in the axial direction, with the vicinity of the outer periphery of the valve plate. Construction. 2. The bearing forced lubrication structure for a hydraulic motor according to claim 1, wherein the fluidizing means is a spiral groove formed on an outer peripheral portion of the rotary shaft. 3. The bearing forced lubrication structure for a hydraulic motor according to claim 1, wherein the fluidizing means is a blade attached to an outer peripheral portion of a rotary shaft.