JPH08247023A - Swash plate type piston pump and motor - Google Patents

Abstract

PURPOSE: To improve the durability of a member slidingly supporting a swash plate and improve positioning accuracy. CONSTITUTION: The angle of a swash plate 26 is freely adjusted in a piston pump and a motor. A semicylindrical recess 31 is formed at part of a housing 20 on the cylindrical back face 30 of the swash plate 26, a nearly semicylindrical bush plate 33 slidably supporting the back face 30 of the swash plate 26 is arranged on the recess 31, the through hole 34 of a main shaft 21 penetrating the swash plate 26 is provided at the center section of the bush plate 33, and the outer periphery of a bearing 35 supporting the main shaft 21 on the housing 20 is coupled with the through hole 34.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a swash plate type piston pump.
Related to motor improvement.

[0002]

2. Description of the Related Art In a piston pump / motor in which the tilt angle of a swash plate is variably controlled, a pair of arcuate bushes are used to support the back surface of the swash plate in a slidable manner with respect to a housing. There is a thing (Actual exploitation Sho 63-7557)
No. 1).

As shown in FIG. 7, the semicylindrical back surface 10a of the swash plate 10 is slidably supported by a pair of arcuate bushes 11 arranged in parallel. in this case,
The bush 11 is formed by a circular arc-shaped plate having the same curvature as the cylindrical back surface 10a of the swash plate 10. The bush 11 is firmly fixed to a housing (not shown) by a knock pin or an adhesive so that the bush 11 does not move. To be done.

The swash plate 10 rotates about the trunnion shaft 13, and at this time, the back surface 10a slides along the inner surface of the bush 11. By changing the tilt angle of the swash plate 10, the effective strokes of a plurality of pistons arranged in a cylinder block (not shown) are changed, which changes the discharge amount per rotation in the case of a piston pump, and the piston motor In the case of, the motor rotation speed changes.

[0005]

However, when the back surface 10a of the swash plate 10 is supported by the pair of strip-shaped arc-shaped bushes 11 as described above, the sliding area with respect to the swash plate 10 is small, so that the high pressure is high. Has a drawback that it is not suitable for high-pressure pumps and motors, because the load per unit area becomes large when it acts, causing problems in durability.

When fixing a set of bushes 11 by using knock pins or the like, it is necessary to accurately control the height of the knock pins in accordance with the thickness of the bushes 11, which is troublesome to process and the bushes 11 need to be fixed. The thickness cannot be too thin.

Furthermore, it is necessary to fix a set of bushes 11 in parallel accurately, and the coaxiality (circularity) of the bushes 11 must be controlled very strictly, which increases the production cost. It was also the cause.

The present invention aims to solve such a problem.

[0009]

According to a first aspect of the invention, a cylinder block which rotates integrally with a main shaft is arranged inside a housing, and a plurality of pistons are arranged on the same circumference of the cylinder block. In a piston pump / motor whose tip is brought into contact with a swash plate and whose swash plate angle is freely adjustable, a semi-cylindrical recess is formed in a part of the housing located on the cylindrical back surface of the swash plate. A semi-cylindrical bush plate that supports the back surface of the swash plate in a slidable manner is provided in this recess, and a through hole for the main shaft that penetrates the swash plate is provided in the center of the bush plate. The outer periphery of the bearing that supports the spindle in the housing was fitted into the through hole.

[0010]

In the first aspect of the invention, the back surface of the swash plate is slidably supported entirely in the recess of the housing through the bush plate having a substantially semi-cylindrical shape. For this reason, the sliding area of the swash plate becomes large, the average surface pressure is reduced even with a high load, and the durability is improved.

Since the bush plate is closely sandwiched between the recess of the housing and the back surface of the swash plate, and the bearing of the main shaft is fitted in the central portion of the bush plate, no special fixing member is required. Accurately positioned.

[0012]

EXAMPLE This example is an example applied as a piston pump. In FIGS. 1 to 3, 20 is a housing, 21 is a main shaft penetrating the housing 20, and a cylinder block 23 rotates integrally with the main shaft 21. Mounted on.
In the cylinder block 23, a plurality of pistons 24 are arranged at equal intervals on the same circumference around the main shaft 21, and the pistons 24 slide on the cylinder 25.

The tip of the piston 24 contacts the swash plate 26 via the shoe 27, and expands and contracts with a stroke according to the inclination angle of the swash plate 26 as the cylinder block 23 rotates via the main shaft 21. Due to the reciprocating motion of the piston 24, the valve plate 28 that is in sliding contact with the bottom surface of the cylinder block 23.
The fluid is sucked into the cylinder 25 through the suction port and the fluid is pressurized and sent out through the discharge port.

The back surface 30 of the swash plate 26 is formed in a semi-cylindrical shape, and is in close contact with a semi-cylindrical concave portion 31 formed at a corresponding position of the housing 20 via a bush plate 33 and is freely slidable. Supported.

That is, the back surface 30 of the swash plate 26 is
Is formed with a part of the circumference centered on the center of rotation of
Moreover, the housing 20 has the same center as the back surface 30.
A semi-cylindrical concave portion 31 is formed in each of them, and a semi-cylindrical bush plate 33 having a predetermined thickness is sandwiched therebetween.

A through hole 34 through which the main shaft 21 penetrates is provided in the central portion of the bush plate 33, and the through hole 34 has an outer side of a bearing 35 for supporting the main shaft 21 in a penetrating portion of the housing 20. The cylinder is fitted and the bush plate 33 is positioned.

As shown in FIGS. 4 to 6, the bush plate 33 is formed by rolling a rectangular plate material into a semi-cylindrical shape, and a through hole 34 is formed in the center thereof.

A through hole 36 is formed in the swash plate 26 so that the swash plate 26 does not interfere with the main shaft 21 even if the swash plate 26 is tilted in one direction from the neutral position (zero tilt). The through hole 36 is a bearing 3 that fits into the bush plate 33.
An opening recess 37 larger than the through hole 36 is formed facing the cylindrical back surface 30 so as not to interfere with the hole 5.

Therefore, the back surface 30 of the swash plate 26 contacts the bush plate 33 in the hatched area around the opening recess 37.

As shown in FIGS. 2 and 3, the swash plate 2
A hydraulic piston 39 is provided in a part of the housing 20 in order to change the inclination angle of the piston 6.
Due to the displacement of the swash plate 26, the pin 41 projected from the swash plate 26 is driven by the piston 39 to incline the swash plate 26.

With the above construction, the operation will be described below.

The cylinder block 2 is rotated by the rotation of the main shaft 21.
3, the piston 24 reciprocates while slidingly contacting the swash plate 26, and sucks fluid into the cylinder 25.
And discharge.

Depending on the inclination angle of the swash plate 26, the piston 24
Stroke changes, and the amount of fluid discharged per revolution also changes.

The back surface 30 of the swash plate 26 is slidably supported in the semi-cylindrical recess 31 of the housing 20 via a bush plate 33. Since the bush plate 33 is in sliding contact with the entire rear surface 30 and is supported by a large area, the surface pressure of the sliding surface of the swash plate 26 is reduced. Therefore, sufficient durability is ensured even when the pump is used as a high-pressure type pump that exerts a large reaction force on the swash plate 26.

On the other hand, the bush plate 33 is sandwiched between the semi-cylindrical concave portion 31 and the semi-cylindrical rear surface 30 of the swash plate 26, and is fitted in the through hole 34 in the central portion of the bearing 3.
Since the position is determined by 5, it can be held at the same position without positioning by special fixing means. Therefore, it is not necessary to use a knock pin or an adhesive for positioning as in the conventional case, and positioning and fixing can be performed very easily.

It is obvious that the present invention can also be applied to a piston motor.

[0027]

As described above, according to the present invention, the back surface of the swash plate is slidably supported entirely in the recess of the housing through the bush plate having a substantially semi-cylindrical shape.
The sliding area of the swash plate is large, the average surface pressure is reduced even under high load, and the durability is improved, and the bush plate is in close contact with the recess of the housing and the back surface of the swash plate. Since the bearing of the main shaft is fitted in the central portion thereof while being sandwiched, accurate positioning is possible without requiring a special fixing member.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view of the same taken along line XX.

FIG. 3 is a Y-Y sectional view of the same.

FIG. 4 shows a bush plate, (A) is a plan view and (B) is a sectional view.

5A and 5B show a swash plate, in which FIG. 5A is a rear view and FIG. 5B is a sectional view.

FIG. 6 is an exploded perspective view of a swash plate and a bush plate.

FIG. 7 is a perspective view of a conventional example.

[Explanation of symbols]

 20 Housing 21 Spindle 23 Cylinder Block 26 Swash Plate 30 Back 31 Recess 33 Bush Plate 34 Through Hole 35 Bearing 37 Open Recess

Claims (1)

[Claims] 1. A cylinder block which rotates integrally with a main shaft is arranged inside a housing, a plurality of pistons are arranged on the same circumference of the cylinder block, and a tip end portion of the piston is brought into contact with a swash plate. In a piston pump / motor in which the angle of the swash plate is freely adjustable, a semi-cylindrical recess is formed in a part of the housing located on the cylindrical back surface of the swash plate, and the back surface of the swash plate is formed in this recess. A semi-cylindrical bush plate for freely sliding support is provided, a main shaft through hole that penetrates the swash plate is provided in the center of the bush plate, and the main shaft is supported in the housing in this through hole. A swash plate type piston pump / motor characterized by fitting the outer periphery of the.