JPH0441258Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an axial piston type fluid machine in which the movement of a cylinder block is stabilized by a spherical body.

[Conventional technology]

A fluid machine such as an axial piston type fluid pump or motor is, as shown in the cross-sectional view of Fig. 2,
A cylinder block 10 in which a plurality of cylinders 11 are arranged on the same circumference around a rotating body 40 is connected to the rotating shaft 40 by a known method such as a spline 15 or a key.
A piston 12 is attached to a spline 41 provided in the cylinder 11, and a piston 12 is attached to a spline 41 provided in the cylinder 11.
It is arranged to slide in a direction parallel to 0. A cylinder port 13 communicating with each cylinder 11 is opened in the cylinder block 10, and is opened toward the valve plate 20 side to communicate with an inlet port and a discharge port provided in the valve plate 20. The end face 14 of the cylinder block 10 is arranged opposite the end face 24 of the valve plate 20. Cylinder block 10, valve plate 20
The rotating shaft 40 is built into the casing 30, and the rotating shaft 40 is supported by the end plate 29 and the casing 30 via bearings 50 and 75. Further, the end plate 29 is attached to one end of the casing 30, and is provided with an inlet 31 and an outlet 32 that communicate with the inlet and outlet opened in the valve plate 20.

On the other hand, a shoe 73 is attached to one end of the piston 12 so as to freely rotate, and the sliding surface of the shoe 73 is configured to slide on a swash plate 70 provided inside the casing 30. , are pressed by a spring 74 via a retainer 71 and a retainer ball 72.

In such an axial piston type fluid machine, the cylinder block 10 is connected to the valve plate 20.
In order to prevent the two end surfaces 14 and 24 from floating up and separating, the spring 7 is compressed with the necessary amount of compression.
4 is provided so that the cylinder block 10 is always pressed against the valve plate 20.

[Problem that the invention attempts to solve]

A spring 74 is used to prevent the cylinder block 10 from floating up and separating from the valve plate 20.
One end of the spring 74 pushes the retainer ball 72, the retainer ball 72 pushes the retainer 71, and the retainer 71 presses the shoe 73 against the swash plate 70 provided in the casing, while the other end of the spring 74 pushes the retainer ball 72. presses the cylinder block 10, and the cylinder block 10 is pressed against the valve plate 20.

Note that the casing 30, end plate 29, and swash plate 70 are integrally coupled.

Here, since the force with which the cylinder block 10 is pressed against the valve plate 20 depends on the amount of compression of the spring 74, it is fixed at a constant value.
On the other hand, the cylinder block 10 is connected to the valve plate 2.
The reason why the cylinder block 10 floats up and separates from zero is because the centrifugal force acting on the combined body of the piston 12 and the shoe 73 generates a moment that causes the cylinder block 10 to tilt.

Incidentally, if the cylinder block 10 is inclined with respect to the valve plate 20 and the end faces 14 and 24 are separated, there is a problem in that high pressure fluid leaks through the resulting gap, reducing the volumetric efficiency of the fluid machine. In addition, the above-mentioned piston 12 and shoe 7
Since the centrifugal force acting on the joint 3 increases in proportion to the square of the rotational speed, an axial piston type fluid machine must be used to keep the cylinder block 10 stably pressed against the valve plate 20 by the spring 74. It is necessary to set the spring force of the spring 74 so that the cylinder block 10 does not tilt even under centrifugal force at the highest rotational speed in the range. For this reason, even at low rotational speeds, that is, when the centrifugal force is small, the cylinder block 10 is pressed against the valve plate 20 with an unnecessarily large spring force, resulting in a reduction in torque efficiency at low rotational speeds and a loss in the cylinder block sliding surface 14. Alternatively, problems such as a decrease in the durability of the sliding surface 24 of the valve plate 20 that slides thereon may occur.

This invention improves the above-mentioned problems of conventional fluid machines, and the pressing force increases at high rotation speeds.
The cylinder block 10 is stably pressed against the valve plate 20 to maintain good adhesion between the end surfaces 14 and 24, and when the rotation speed is low, the pressing force is reduced to prevent the cylinder block from tilting or lifting. In addition to having the ability to
It is an object of the present invention to provide an axial piston type fluid machine that can prevent a decrease in torque efficiency and maintain good durability of sliding surfaces.

[Means for solving problems]

Therefore, in the axial piston type fluid machine of the present invention, pistons are inserted into a plurality of cylinders that are bored on the circumference around the rotation axis center of a cylinder block attached to a rotation axis and parallel to the rotation axis. ,
In an axial piston fluid machine in which one end of the piston is slid on a swash plate having a sliding surface inclined with respect to the rotation axis, the piston is given reciprocating motion and fluid is driven. a spherical body receiving part provided on the outer periphery of the block, into which a spherical body is fitted and supporting the component of the force exerted by the spherical body in the direction of the rotating shaft fluid inlet/outlet; and a casing facing the spherical body receiving part of the cylinder block. and a truncated conical surface part that extends in the direction of the fluid inlet and outlet of the rotating shaft with which the spherical body comes into contact. is pressed against the valve plate appropriately.

[Effect]

With the above-described structure of the present invention, it is possible to generate a force that pushes the cylinder block against the valve plate in proportion to the centrifugal force that acts on the cylinder block and tends to tilt it. In other words, when the cylinder block rotates, the spherical body is pressed against the casing by centrifugal force, and since the casing is a truncated cone-shaped surface that spreads toward the fluid inlet and outlet of the rotation axis, the spherical body receives an oblique force from the casing, and the spherical body is balanced by receiving force from the cylinder block in the axial direction. A reaction force of this axial force acts on the cylinder block to press the cylinder block against the valve plate with an appropriate force. This prevents the cylinder block from tilting at high speeds, and
It works to improve mechanical efficiency at low speeds and durability of sliding surfaces.

〔Example〕

Hereinafter, an axial piston type fluid machine as an embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a sectional view of the fluid machine.

Components having the same reference numerals as those in FIG. 2 showing the conventional example are the same members as those described above and have the same functions, so a description thereof will be omitted.

The cylinder block 10', which has a bulged end near the valve plate 20, is formed with slopes 4 in a direction toward the rotation axis from the outer periphery of the bulged portions at equal intervals in the same direction. Incidentally, the slope 4 may be formed over the entire circumference of the cylinder block 10'.

Holes 2 are bored at equal intervals in the radial direction in the middle of this slope 4. A spherical body 1 is inserted into this hole 2.

On the other hand, the end of the casing 30' on the side where the end plate 29 is attached is also bulged outward, and a slope 3 having the same slope angle as the slope provided on the cylinder block 10' is completely formed on the inner surface of the bulge. It is formed around the circumference. The spherical body 1 is attached to this slope 3.
are placed so that they touch each other. When the spherical body 1 is inserted into the hole 2 and assembled, the spherical body 1 is guided by the hole 2 and can come into contact with the slope 3 provided on the casing 30'. You can prevent it from falling off from 2. As the cylinder block 10' rotates, the spherical body 1 in the hole 2 rotates together with the cylinder block 10', and a centrifugal force acts on it. This force acts on the slope 3 provided on the casing 30', and its component force acts on the cylinder block 10' via the spherical body 1, and the direction of the force acts in the direction of pressing the cylinder block 10' against the valve plate 20. can be done. The force that presses this cylinder block 10' against the valve plate 20 is different from the force applied by the conventional spring 74, and is proportional to the square of the rotation speed, and is large at high speed rotation and small at low speed rotation. Even during rotation, the cylinder block 10' does not tilt, and high-pressure fluid does not leak and reduce volumetric efficiency. Furthermore, at low rotational speeds, the centrifugal force acting on the cylinder block 10' is small, and the pressing force exerted on the cylinder block 10' by the spherical body 1 against the valve plate 20 is small, resulting in a decrease in torque efficiency or a decrease in cylinder block 10', valve plate 20. Problems such as a decrease in the durability of the sliding surface are eliminated.

In addition, in this embodiment, the cylinder block 1
Although the example in which the slope 4 is provided on the bulge at the end of 0' is shown,
Instead of this, a step-like structure is formed and a hole 2 is formed in the middle.
The centrifugal force acting on the cylinder block 10' applied to the spherical body 1 inserted into the required hole 2 can generate a component in the direction of the rotational axis by the inclined surface 3 provided on the casing 30'. It's fine as long as it's something.

[Effect of idea]

As described in detail above, according to the axial piston type fluid machine of the present invention, the tilting moment of the cylinder block, which is generated when the cylinder block including the piston shoe rotates, is absorbed by using the slope of the spherical body and the casing. This generates a force that resists the tilting of the cylinder block from the centrifugal force acting on the cylinder block, preventing the cylinder block from tilting, suppressing leakage between the valve plate and cylinder block at high speeds, and preventing leakage at low speeds. The mechanical efficiency of the cylinder block and the durability of the sliding surfaces of the valve plate can be improved.

[Brief explanation of drawings]

FIG. 1 shows a sectional view of an axial piston type fluid machine as an embodiment of the present invention. FIG. 2 shows a sectional view of a conventional axial piston type fluid machine. 1... Spherical body, 2... Hole, 3... Slope, 10',
10... Cylinder block, 11... Cylinder hole, 12... Piston, 13... Cylinder port, 14... Valve plate sliding surface, 15... Cylinder block spline, 20... Valve plate, 24... Cylinder Block sliding surface, 2
9... End plate, 30', 30... Casing, 33... Space between casing 30 and cylinder block 10, 40... Shaft, 41...
... Spline of shaft 40, 50... Bearing, 70... Inclined surface provided at one end of casing, 71... Retainer, 72... Retainer ball, 73... Show, 74... Spring, 75
... Bearing, 76 ... Seal box, 77
...Seal, 78...Key.

Claims (1)

[Scope of utility model registration request] Pistons are fitted into a plurality of cylinders that are bored parallel to the rotation axis on a circumference centered on the rotation axis of a cylinder block attached to the rotation axis, and one end of the piston is tilted with respect to the rotation axis. In an axial piston fluid machine in which a piston is caused to reciprocate and drive fluid by sliding on a swash plate having a sliding surface, a spherical body is installed on the outer periphery of the cylinder block. a spherical body receiving part that supports a component of the force exerted by the spherical body in the direction of the fluid inlet/outlet of the rotating shaft; and a rotating shaft that is provided in a casing facing the spherical body receiving part of the cylinder block and in contact with the spherical body. An axial piston type fluid machine characterized by comprising a truncated conical surface portion that spreads in the direction of a fluid inlet and outlet.