JP2002039047A - Swash plate type piston motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a swash plate type piston motor, wherein a hole 36 is given as in concave form on the rear terminal face of a cylinder block 16, and a boss portion 38 is given as in convex form on the front terminal face of a housing cover 11 to this hole 36, the boss portion 38 is connected to the swash plate type piston motor through a bearing 37, then the oil film that is formed on the sliding surface can be kept in a suitable thickness, and the duarability of the bearing 37 can be improved. SOLUTION: A hydraulic oil introducing hole 40 which introduces the hydraulic oil to a gap portion 39 located between the hole 36 and the boss portion 38, is put on the housing cover 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swash plate type piston motor used as a motor for driving a swing body of a construction machine, for example.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a swash plate type piston motor of this type has a cylindrical housing 10 with a rear end opened and a rear end opening of the housing 10 closed. And a housing cover 11.
Inside the housing 10, a swash plate 12, a piston 14, a cylinder block 16, a valve plate 18, a motor shaft 2
3 and the like are provided.

The swash plate 12 has a front surface fixed to an inner surface of the housing 10 by bolts or the like, and a shoe 13 is slidably abutted on the back surface of the swash plate 12.

[0004] A plurality of pistons 14 are provided in the housing 10. Each piston 14 has a spherical head 15
And is swingably engaged with the shoe 13 via the spherical head 15.

[0005] The cylinder block 16 is formed in a columnar shape.
A plurality of cylinder chambers 17 for slidably holding 4 are formed.

[0006] The valve plate 18 is formed in an annular shape. Further, the valve plate 18 is mounted on the cylinder block 16.
A crescent-shaped pressure oil supply / discharge port 19 for supplying / discharging pressure oil to / from the cylinder chamber 17 of the cylinder block 16 is provided on the valve plate 18. .

The motor shaft 23 has a retainer portion 24, and a ring-shaped leaf spring 26 for pressing the shoe 13 against the swash plate 12 via a return plate 25 is attached to the retainer portion 24. The motor shaft 23 passes through a center hole of the swash plate 12 and is rotatably supported by a boss 27 formed at the front end of the housing 10 via a bearing 28. Further, the motor shaft 23 is connected to the cylinder block 1
6 is formed integrally with the cylinder block 16 so as to extend from the front end face.

The housing cover 11 is fixed to the housing 10 by bolts or the like. The housing cover 11 has a pressure oil supply / discharge port 19 of a valve plate 18,
Pressure oil supply ports 20 and 20 for supplying and discharging pressure oil
And pressure oil discharge ports 21 and 21, and a leak oil discharge port 22 for discharging hydraulic oil leaked in the housing 10 (hereinafter referred to as leak oil) to the outside.

In such a configuration, the cylinder block 16 is connected to the pressure oil supply port 20 of the housing cover 11.
The pressure oil is supplied to the cylinder chamber 17 through the pressure oil supply / discharge port 19 of the valve plate 18, and the piston 14 is moved in a direction in which the piston 14 is pushed out of the cylinder chamber 17 by the pressure oil supplied to the cylinder chamber 17. When the shoe 13 is pressed against the swash plate 12, the reaction force at that time acts on the cylinder block 16 via the piston 14 as a component in the rotation direction, so that the cylinder block 16 and the motor shaft 23 start rotating.

By the way, in such a swash plate type piston motor, as described above, the cylinder block 1 is extended so that the motor shaft 23 extends from the front end face of the cylinder block 16.
6, it is necessary to support the cylinder block 16 with bearings instead of supporting the rear end of the motor shaft 23 with bearings. Therefore, conventionally, a hole 36 is formed in the rear end face of the cylinder block 16, and a cylindrical boss 38 protruding from the front end face of the housing cover 11 is engaged with the hole 36 via a bearing 37. ing.

[0011]

However, in the above-described swash plate type piston motor, the operating internal oil used for lubrication of the bearings 28 and 37 is combined with the operating oil injected into the housing 10 before starting. Internal leak oil. Paying attention to the gap 39 between the hole 36 and the boss 38, the hydraulic oil in the gap 39 has some flow due to internal leak, but most of the oil stays in the gap 39. Therefore,
If the operating oil temperature or the housing temperature rises to meet the demand for a further high-speed rotation of the motor in the future, the oil film formed on the sliding surface of the bearing 37 is kept at an appropriate thickness. There was a drawback that it became difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to form a hole in a rear end surface of a cylinder block, and a boss portion protruding from the front end surface of a housing cover in the hole. In the swash plate type piston motor engaged with the bearing via the bearing, the oil film formed on the sliding surface of the bearing interposed between the hole and the boss can be maintained at an appropriate thickness,
An object of the present invention is to provide a swash plate type piston motor capable of improving the durability and the like of a bearing.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a housing formed into a tubular shape with a rear end opened, a housing cover for closing the rear end opening of the housing, A swash plate provided in the housing, a plurality of pistons swingably engaged with the swash plate via shoes, and a cylinder block having a plurality of cylinder chambers slidably holding these pistons. An annular valve plate provided between the cylinder block and the housing cover, and a motor shaft integrally formed with the cylinder block so as to extend from a front end face of the cylinder block opposite to the valve plate. Comprising a hole in the rear end surface of the cylinder block,
In a swash plate type piston motor in which a boss protruding from the front end face of the housing cover is engaged with the hole via a bearing, hydraulic oil introduction for introducing hydraulic oil into a gap between the hole and the boss. The means is provided on the housing cover or the motor shaft.

In this case, the hydraulic oil introduced into the gap may flow through the bearing, and may further flow through the space between the valve plate and the housing cover, and then may be discharged from the housing. It is preferable that a groove for allowing the hydraulic oil introduced into the gap to flow between the housing cover and the valve plate is provided in one or both of the valve plate and the housing cover. Further, the swash plate type piston motor according to the present invention further includes a mechanical brake mechanism for applying a brake force to the motor shaft, and a brake release hydraulic timer for releasing the brake force of the mechanical brake mechanism by hydraulic pressure. The hydraulic oil introduced into the hydraulic fluid may be oil supplied to a brake release hydraulic timer.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the internal structure of a swash plate type piston motor according to a first embodiment of the present invention. In FIG. 1, the swash plate type piston motor according to the present embodiment includes a cylindrical housing 10 having a rear end opened, and a housing cover 11 for closing the rear end opening of the housing 10. Inside the swash plate 12, a piston 14, a cylinder block 16, a valve plate 18, a motor shaft 23, a mechanical brake mechanism 2
9 and the like are provided.

A front surface of the swash plate 12 is fixed to an inner surface of the housing 10 by bolts or the like, and a shoe 13 is slidably abutted on a rear surface of the swash plate 12.

A plurality of pistons 14 are provided in the housing 10. Each piston 14 has a spherical head 15
And is swingably engaged with the shoe 13 via the spherical head 15.

The cylinder block 16 is formed in a columnar shape.
A plurality of cylinder chambers 17 for slidably holding 4 are formed.

The valve plate 18 is formed in an annular shape. Further, the valve plate 18 is mounted on the cylinder block 16.
A crescent-shaped pressure oil supply / discharge port 19 for supplying / discharging pressure oil to / from the cylinder chamber 17 of the cylinder block 16 is provided on the valve plate 18. .

The motor shaft 23 has a retainer portion 24, and a ring-shaped leaf spring 26 for pressing the shoe 13 against the swash plate 12 via a return plate 25 is attached to the retainer portion 24. The motor shaft 23 passes through a center hole of the swash plate 12 and is rotatably supported by a boss 27 formed at the front end of the housing 10 via a bearing 28. Further, the motor shaft 23 is connected to the cylinder block 1
6 is formed integrally with the cylinder block 16 so as to extend from the front end face.

The mechanical brake mechanism 29 includes a fixed brake plate 30 fixed to the cylinder block 16, a movable brake plate 31 provided on the outer periphery of the cylinder block 16 opposite to the fixed brake plate 30, and a movable brake plate 31 Piston 32 for driving the cylinder piston 16 forward and backward in the axial direction of the cylinder block 16;
And a plurality of compression coil springs 33 for pressing the movable brake plate 31 against the fixed brake plate 30 through the compression coil spring 33. Further, the mechanical brake mechanism 29 has a brake piston chamber 34, and pressure oil is supplied from the brake release hydraulic timer 35 to the brake piston chamber 34, whereby the brake piston 32 and the movable brake plate 31 are compressed by a compression coil spring. When it moves backward in the figure against the spring force of 33, the friction braking force generated between the fixed brake plate 30 and the movable brake plate 31 is released. Accordingly, pressure oil is supplied to the brake piston chamber 34 of the mechanical brake mechanism 29 from the brake release hydraulic timer 35, so that the movable brake plate 31 and the brake piston 32 oppose the spring force of the compression coil spring 33 to the right in the figure. When it moves in the direction, the braking force on the motor shaft 23 is released, and the cylinder block 16 and the motor shaft 23 become rotatable.

The housing cover 11 is fixed to the housing 10 by bolts or the like. The housing cover 11 has a pressure oil supply / discharge port 19 of a valve plate 18,
Pressure oil supply ports 20 and 20 for supplying and discharging pressure oil
And a pressure oil discharge port 21, 21, and a leak oil discharge port 22 for discharging hydraulic oil leaked in the housing 10 to the outside. A cylinder block 16 is provided on the front end face of the housing cover 11.
A column-shaped boss portion 38 is engaged with a hole 36 formed in the rear end surface of the boss portion so as to engage via a bearing 37.

The pressure oil supply ports 20 and 20 and the pressure oil discharge ports 21 and 21 have a large-diameter hole opening toward the valve plate 18 and a small-diameter hole connected to the rear end of the large-diameter hole. A ring-shaped bush 44 is slidably provided in the large-diameter hole portion of each of the ports 20 and 21, and an elastic body that abuts the bush 44 on the back surface of the valve plate 18, preferably Is a spring 45 such as a disc spring
Is provided.

Each bush 44 is provided on the large-diameter portion with its front end slightly projecting from the front end of the housing cover 11, so that oil flows between the housing cover 11 and the valve plate 18. There is formed a gap for making it clear.

The housing cover 11 is provided with a hydraulic oil introduction hole 40 as hydraulic oil introduction means for introducing hydraulic oil into the gap 39 between the hole 36 and the boss 38. The hydraulic oil introduction hole 40 communicates with the brake release hydraulic timer 35 via the hydraulic oil supply line 41 and the throttle 43, and accordingly, the hydraulic oil introduction hole 40 communicates with the operation oil supplied to the brake release hydraulic timer 35. The oil is always supplied via the throttle 43 and the hydraulic oil supply line 41.

In the swash plate type piston motor configured as described above, the brake is released from the brake release hydraulic timer 35,
After the pressure is reduced by the throttle 43, the hydraulic oil supplied to the hydraulic oil supply pipe 41 is supplied to the gap 39 through the hydraulic oil introduction hole 40.
When the oil is introduced into the gap 39, the oil in the gap 39 flows through the bearing 37 together with the hydraulic oil introduced into the gap 39, and further flows between the housing cover 11 and the valve plate 18. The oil is discharged from the leak oil discharge port 22 to the outside.

Therefore, in the present embodiment, the oil used for lubricating the bearing 37 does not stay in the gap portion 39 and does not become hot during high-speed operation. It is possible to keep the thickness at an appropriate thickness, thereby suppressing wear of the bearing 37. Also,
The oil used for lubrication of the bearing 37 does not stay in the gap portion 39 and is always discharged to the outside through the leak oil discharge port 22. Therefore, the sliding surface of the bearing 37 may be damaged by foreign matter such as contamination. Can be suppressed. Thus, in the present embodiment, the durability of the bearing 37 can be improved. Further, since a part of the supply oil to the hydraulic timer 35 for releasing the braking force of the mechanical brake mechanism 29 by the hydraulic pressure is supplied to the gap 39 from the hydraulic oil introduction hole 40, the hydraulic oil is supplied to the hydraulic oil introduction hole 40. The oil film formed on the sliding surface of the bearing 37 can be kept at an appropriate thickness without newly providing a hydraulic pump or the like for supplying oil.

In the above-described embodiment, the hydraulic oil introduction hole 40 as the hydraulic oil introduction means is provided in the housing cover 11, but the present invention is not limited to this. The motor shaft 23 may be provided integrally with the block 16. In the above-described embodiment, the hydraulic timer 35 is provided separately from the housing 10. However, the hydraulic timer 35 may be provided integrally with the housing 10, and in this case, the hydraulic oil from the hydraulic timer 35 is introduced into the hydraulic oil. It goes without saying that a passage for supplying the hole 40 needs to be formed in the housing 10 and the housing cover 11. Further, in the above-described embodiment, the leak oil discharge port 22 is connected to the housing cover 11.
The present invention is applied to the swash plate type piston motor provided in the above, but the present invention is also applicable to a swash plate type piston motor in which the leak oil discharge port 22 is provided in the housing 10.

The present invention is not limited to the above embodiment. For example, as in the second embodiment shown in FIG. 2 or the third embodiment shown in FIG. 3, a groove 42 for allowing the hydraulic oil introduced into the gap 39 to flow between the housing cover 11 and the valve plate 18. May be provided on one or both of the valve plate 18 and the housing cover 11.

A groove 42 for allowing the hydraulic oil introduced into the gap 39 to flow between the housing cover 11 and the valve plate 18 is provided in one or both of the valve plate 18 and the housing cover 11. This facilitates the flow of the hydraulic oil introduced into the gap portion 39 through the bearing 37, so that the thickness of the oil film formed on the sliding surface of the bearing 37 can be more reliably maintained at an appropriate thickness.

[0032]

As described above, according to the present invention,
In the swash plate type piston motor in which a hole is formed in the rear end surface of the cylinder block and a boss protruding from the front end surface of the housing cover is engaged with the hole through a bearing, the hole and the boss are formed. It is possible to provide a swash plate type piston motor in which an oil film formed on a sliding surface of a bearing interposed therebetween can be maintained at an appropriate thickness, and durability and the like of the bearing can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an internal structure of a swash plate type piston motor according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a second embodiment of the present invention;
It is a rear view of a valve plate.

FIG. 3 is a sectional view showing an internal structure of a swash plate type piston motor according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing an internal structure of a conventional swash plate type piston motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Housing 11 Housing cover 12 Swash plate 13 Shoe 14 Piston 16 Cylinder block 17 Cylinder chamber 18 Valve plate 23 Motor shaft 29 Mechanical brake mechanism 35 Hydraulic timer for brake release 36 Hole 37 Bearing 38 Boss 39 Gap 40 Hydraulic oil introduction hole 42 groove

Claims (6)

[Claims] A housing formed in a cylindrical shape with a rear end opened; a housing cover for closing the rear end opening of the housing; a swash plate provided in the housing;
A plurality of pistons that swingably engage the swash plate via shoes, a cylinder block having a plurality of cylinder chambers that slidably hold the pistons, and a cylinder block and the housing cover. And a motor shaft integrally formed with the cylinder block so as to extend from a front end face of the cylinder block opposite to the valve plate, and a rear end face of the cylinder block. A swash plate type piston motor in which a boss portion protruding from the front end surface of the housing cover is engaged with the hole portion through a bearing, and a hole is formed in the gap portion between the hole portion and the boss portion. A swash plate type piston motor, wherein a hydraulic oil introducing means for introducing hydraulic oil is provided on the housing cover or the motor shaft. 2. The slant according to claim 1, wherein the hydraulic oil introduced into the gap flows through the bearing, further flows between the valve plate and the housing cover, and is then discharged from the housing. Plate type piston motor. 3. The valve plate according to claim 1, wherein a groove for allowing the hydraulic oil introduced into the gap to flow between the housing cover and the valve plate is provided in the valve plate. Swash plate type piston motor. 4. The housing cover according to claim 1, wherein a groove for allowing the hydraulic oil introduced into the gap to flow between the housing cover and the valve plate is provided in the housing cover. The swash plate type piston motor according to claim 1. 5. The system according to claim 1, further comprising a mechanical brake mechanism for applying a braking force to said motor shaft, and a brake release hydraulic timer for releasing the braking force of said mechanical brake mechanism by hydraulic pressure. The swash plate type piston motor according to claim 1. 6. The swash plate type piston motor according to claim 5, wherein the hydraulic oil introduced into the gap is oil supplied to the brake release hydraulic timer.