JPH0437267Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a swash plate type hydraulic rotating machine, and more particularly to a support mechanism for a valve plate thereof.

[Prior Art] Fig. 2 is a vertical sectional view showing a conventional example of a swash plate type hydraulic rotating machine, and Fig. 3 is an explanation showing the relationship of acting forces between the piston, shoe, cylinder block, and swash plate, which will be described later. 4 is a plan view of the valve plate, and FIG. 5 is a detailed longitudinal sectional view of the valve plate support portion of FIG. 2.

In these figures, 1 is a casing, 2 is a rotating shaft, and the rotating shaft 2 is supported by the casing 1 by a bearing 3 (the bearing at the other end is not shown). 6
is a valve plate, and the valve plate 6 is a liquid passage 6 that communicates with liquid passages 4 and 5 provided in the casing 1 for sucking and discharging hydraulic fluid.
A and 6B, and the movement is restrained by the pin 14 and the bearing 3 and abuts against the casing 1. Reference numeral 7 denotes a cylinder block consisting of a plurality of cylinders surrounding the rotating shaft 2, and the cylinder block 7 is connected to the rotating shaft 2 by a connecting member 2A such as a spline.
It is slidably in contact with the spherical sliding surface of the valve plate 6. The cylinder block 7 has a plurality of cylinders 7A.
A piston 8 is provided within each cylinder 7A so as to be able to reciprocate. The tip of the piston 8 has a ball shape, and a shoe 9 is fitted in a swingable manner so as to surround it.
is in slidable contact with the swash plate 15 by a shoe retainer 11, a ball retainer 10, a spacer 12, and a plurality of springs 13. Further, each cylinder 7A provided in the cylinder block 7 is provided with a port 7B, and the port 7B is intermittently communicated with the liquid passages 6A and 6B provided in the valve plate 6 as the cylinder block 7 rotates. Point 16 in FIG. 4 indicates a position corresponding to the top dead center of the reciprocating motion of the piston 8, and point 17 indicates a position corresponding to the bottom dead center of the piston.

In the hydraulic rotating machine configured as described above, the force between the piston 8, shoe 9, swash plate 15, and cylinder block 7 is controlled by connecting the liquid passages 4 and 6A to the high pressure suction side passage, and the liquid passage 5, A case where the same 6B is used as a motor with a low pressure side discharge passage will be explained. The hydraulic fluid, that is, high pressure oil (pressure P) flowing through the liquid passages 4 and 6A acts on the pressure receiving portion 8A of the piston 8 and pushes the piston 8 to the left in FIG. 3 as an acting force FA. When the acting force FA acts on the swash plate 15 having an inclination angle α via the shoe 9, a force Fb=-FB=-FAtanα is applied to the piston 8 as a reaction force.
It is a well-known fact that the rotary shaft 2 applies rotational force to the rotating shaft 2 via the receiving cylinder block 7 and the connecting member 2A.

In addition, the reaction force Fb causes the rotating shaft 2 to deflect, causing the cylinder block 7 supported by it to bend to the second position.
It is also known to displace it together with the axis of rotation 2 in the X direction of the figure. That is, the cylinder block 7 contacts and slides on the valve plate 6 in an eccentric state proportional to the pressure P.

On the other hand, the valve plate 6 is restricted from moving in a plane perpendicular to the axial direction by the bearing 3, and is also restricted from moving in the rotational direction by the pin 14, so it cannot follow the movement of the cylinder block 7, which rotates eccentrically. .

[Problems to be solved by the invention] In the above conventional valve plate support mechanism of the swash plate type hydraulic rotating machine, the cylinder block 7 is eccentric together with the rotating shaft 2, and the amount of eccentricity increases as the pressure P increases. However, since the valve plate 6 is in contact with the casing 1 with its movement restrained by the bearing 3 and pin 14, the sliding surface is in uneven contact, which may cause seizure or change in the amount of leakage from the sliding surface. Therefore, it is difficult to ensure stable performance.

[Means for Solving the Problems] As a means for solving the above-mentioned problems, the present invention provides a cylinder block consisting of a plurality of reciprocating pistons and cylinders surrounding a rotating shaft, the shaft end surface of which is concave; The axis of the spherical surface is slidably in contact with the concave surface of the piston, and the axis of the spherical surface is moved in the direction connecting the top dead center and bottom dead center of the piston to the axis of the rotating shaft by an amount equivalent to eccentricity when the cylinder block rotates. It is an object of the present invention to provide a swash plate type hydraulic rotary machine characterized by comprising a valve plate mounted on a casing with a displacement of 1.

[Function] Since the present invention is constructed as described above, the center of the spherical surface of the valve plate is set eccentrically in advance by the amount by which the cylinder block rotates when the cylinder block rotates, and is supported on the casing. The centers of the sliding surfaces of the cylinder block and valve plate coincide, creating a stable sliding condition with no uneven contact between the cylinder block and valve plate.

[Embodiment] An embodiment of the present invention will be described with reference to a detailed vertical cross-sectional view of the valve plate support portion in FIG. 1. In the figure, δ is the eccentricity between the bearing center of the rotating shaft 2 and the spherical center of the valve plate 6. The other parts are constructed in the same manner as in FIGS. 2 and 5.

As mentioned above, since the spherical center of the valve plate 6 is supported eccentrically by δ in the X direction of FIG. The centers of the sliding surface of the valve plate 6 coincide with each other, and a stable state of the sliding surface can be created. The amount of eccentricity δ is a value assuming the amount of deflection of the rotating shaft 2 when the hydraulic fluid is at high pressure.

At low pressure, the cylinder block 7 and the valve plate 6 come into contact with each other in a slightly eccentric state, but since the pressure is low, seizure of the sliding surfaces and influence on the amount of leakage are small and do not pose a problem.

In this embodiment, the valve plate 6 is
is supported by the casing 1, but the supporting member may be supported by a member having another shape. As a means to eccentrically center the spherical center of the valve plate 6, a valve plate whose spherical center and support center are aligned may be eccentrically supported, or a valve plate whose spherical center and support center are eccentrically aligned may be eccentrically supported. may be supported.

[Effects of the invention] Since the present invention is constructed as described above, the center of the spherical surface of the valve plate can be shifted from the center of the bearing of the rotating shaft by the amount of eccentricity when the cylinder block rotates, so that the cylinder block can be installed in an eccentric state. Even if the valve plate rotates at a constant speed, the centers of the sliding surfaces between the valve plate and the cylinder block are aligned, so uneven contact during high-pressure operation can be avoided, and a stable state of the sliding surfaces can be maintained. Therefore, problems such as seizure of sliding surfaces and oil leakage are eliminated.

[Brief explanation of the drawing]

Fig. 1 is a detailed longitudinal sectional view of a valve plate support part according to an embodiment of the present invention, Fig. 2 is a longitudinal sectional view of a conventional swash plate type hydraulic rotating machine, and Fig. 3 is a longitudinal sectional view of a swash plate type hydraulic rotating machine. Fig. 4 is a plan view of the valve plate of a swash plate type hydraulic rotating machine, and Fig. 5 is a diagram of the conventional example corresponding to Fig. 1. FIG. 3 is a detailed vertical cross-sectional view of the valve plate support portion. DESCRIPTION OF SYMBOLS 1... Casing, 2... Rotating shaft, 3... Bearing, 6... Valve plate, 7... Cylinder block, 8...
...Piston, 9...Show, 14...Pin, 15
... Swash plate.

Claims (1)

[Scope of utility model registration request] It is composed of a plurality of reciprocating pistons and cylinders surrounding a rotating shaft, and includes a cylinder block whose shaft end surface is concave, and a spherical surface that slidably abuts on the concave surface of the cylinder block, and the top dead center and bottom of the piston. and a valve plate attached to the casing such that the axial center of the spherical surface is shifted by an amount equivalent to the eccentricity during rotation of the cylinder block with respect to the axial center of the rotating shaft in the direction connecting the dead center. Swash plate type hydraulic rotating machine.