CN-116018460-B - Valve plate, cylinder body, hydraulic pump and motor

CN116018460BCN 116018460 BCN116018460 BCN 116018460BCN-116018460-B

Abstract

Provided is a port plate capable of avoiding problems such as a cylinder sticking between the port plate and the end surface of a cylinder even under high-pressure and high-speed conditions. The port plate has a discharge port 52 and a suction port 51 on a circumference centered on the rotation axis 20C, and further has an endless annular oil groove 54 and a plurality of radial oil grooves 55 extending from the annular oil groove 54 toward the outer circumference at a portion of the outer circumference around the rotation axis 20C, and a plurality of outer ring oil grooves 58 are provided at a portion of the outer circumference of the discharge port 52 on the downstream side of the relative rotation in an outer ring region 57 where the radial oil grooves 55 abut against the end surface 40a of the cylinder 40, the plurality of outer ring oil grooves 58 communicate with the annular oil groove 54 and open toward the end surface 40a of the cylinder 40, and the plurality of outer ring oil grooves 58 are provided so that a ratio of an opening area of the plurality of outer ring oil grooves to the end surface 40a of the cylinder 40 is larger on the downstream side of the relative rotation than on the upstream side of the relative rotation.

Inventors

IKEDA MITSUTAKA
HONGO HIROAKI

Assignees

株式会社小松制作所

Dates

Publication Date: 20260508
Application Date: 20210907
Priority Date: 20200914

Claims (14)

1. A port plate which is a port plate of a hydraulic pump/motor and which has a high-pressure side port and a low-pressure side port on a circumference centered on a rotation axis, and which has a first oil groove provided in a ring shape and a plurality of second oil grooves provided on an outer periphery of the high-pressure side port and the low-pressure side port, and which is configured to rotate relatively about the rotation axis with being in contact with an end surface of a cylinder block so that the high-pressure side port and the low-pressure side port alternately communicate with a cylinder bore provided in the cylinder block, In an outer ring region of the second oil grooves abutting against the end face of the cylinder body, at least a portion of the outer periphery of the high-pressure side port on the downstream side of the relative rotation is provided with a plurality of outer ring oil grooves which communicate with the first oil groove and are open toward the end face of the cylinder body, The plurality of outer ring oil grooves are provided such that the ratio of the opening area of the plurality of outer ring oil grooves with respect to the end surface of the cylinder is larger on the downstream side than on the upstream side of the relative rotation.
2. The port plate of claim 1, wherein, The plurality of outer ring oil grooves extend linearly and are inclined with respect to a radial direction about the rotation axis.
3. The port plate of claim 2, wherein, The plurality of outer ring oil grooves are inclined toward the same direction with respect to the radial direction.
4. The port plate of claim 1, wherein, The plurality of outer ring oil grooves are provided only in a portion of the outer ring region on the downstream side of the relative rotation.
5. The port plate of claim 1, wherein, The plurality of outer ring oil grooves are disposed at unequal intervals so that the lengths of the outer ring oil grooves extending from the first oil groove and the opening widths of the outer ring oil grooves with respect to the end surface of the cylinder block are equal to each other, and the intervals between the outer ring oil grooves gradually decrease toward the downstream side of the relative rotation.
6. The port plate of claim 1, wherein, The outer peripheral side ends of the plurality of outer ring oil grooves are closed.
7. A cylinder block which is a hydraulic pump/motor, has a plurality of cylinder bores around a rotation axis, and has a first oil groove formed in a ring shape and a plurality of second oil grooves formed in an outer periphery of the cylinder bores in a portion of an end surface where the plurality of cylinder bores open, the cylinder block being configured to alternately communicate with a high-pressure side port and a low-pressure side port provided in a port plate by relatively rotating the cylinder block in a state where the end surface is brought into contact with the port plate, In the outer ring region of the second oil grooves which is in contact with the port plate, at least a portion on the downstream side of the relative rotation is provided with a plurality of outer ring oil grooves which communicate with the first oil groove and open toward the port plate, The plurality of outer ring oil grooves are arranged such that the ratio of the plurality of outer ring oil grooves to the opening area of the port plate is such that the downstream side of the relative rotation is larger than the upstream side of the relative rotation.
8. The cylinder as claimed in claim 7, wherein, The plurality of outer ring oil grooves extend linearly and are inclined with respect to a radial direction about the rotation axis.
9. The cylinder as claimed in claim 8, wherein, The plurality of outer ring oil grooves are inclined toward the same direction with respect to the radial direction.
10. The cylinder as claimed in claim 7, wherein, The plurality of outer ring oil grooves are provided only in a portion of the outer ring region on the downstream side of the relative rotation.
11. The cylinder as claimed in claim 7, wherein, The plurality of outer ring oil grooves are disposed at unequal intervals so that the distance between the plurality of outer ring oil grooves becomes smaller toward the downstream side of the relative rotation, the extending lengths from the first oil groove and the opening widths with respect to the end face of the port plate being the same as each other.
12. The cylinder as claimed in claim 7, wherein, The outer peripheral side ends of the plurality of outer ring oil grooves are closed.
13. A hydraulic pump/motor is characterized in that, A port plate according to any one of claims 1 to 6.
14. A hydraulic pump/motor is characterized in that, A cylinder as claimed in any one of claims 7 to 12.

Description

Valve plate, cylinder body, hydraulic pump and motor Technical Field The present invention relates to a hydraulic pump/motor having a cylinder body that rotates in a state where an end surface abuts against a port plate, and to a port plate and a cylinder body that are applied to the hydraulic pump/motor. Background Such a hydraulic pump/motor includes a hydraulic pump/motor in which an annular oil groove and a plurality of radial oil grooves are provided between a port plate and an end surface of a cylinder block. The annular oil groove is an annular groove-shaped space having no end and provided at a portion closer to the outer periphery than the high-pressure side port and the low-pressure side port of the port plate. The radial oil grooves extend from the annular oil groove to the outer periphery along the radial direction and are arranged at a plurality of positions which are equally spaced between each other. In this hydraulic pump/motor, oil between the port plate and the end surface of the cylinder is discharged into the casing through the annular oil groove and the radial oil groove. Therefore, there is a risk that it is difficult to maintain an oil film between the port plate and the end face of the cylinder block in a region (hereinafter, referred to as an outer ring region) on the outer periphery of the annular oil groove. In order to solve the above-described problems, there has been conventionally provided an invention in which an oil reservoir is formed in a portion on the outer periphery of an annular oil groove to lubricate an outer ring region (for example, see patent document 1). Patent document 1 Japanese patent laid-open publication No. 2010-116813 Disclosure of Invention On the other hand, there is a demand for high-pressure and high-speed hydraulic pumps and motors at present. Even in the case of providing the above-mentioned oil reservoir in the hydraulic pump/motor with high pressure and high speed, it is difficult to maintain the oil film in the outer ring region, and thus there is a risk of problems such as seizing and abrasion occurring between the port plate and the end face of the cylinder block. The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a port plate, a cylinder block, and a hydraulic pump/motor capable of avoiding the occurrence of problems such as cylinder sticking and abrasion between the port plate and an end surface of the cylinder block even in a high-pressure and high-speed condition. In order to achieve the above object, the present invention provides a hydraulic pump/motor valve plate having a high-pressure side port and a low-pressure side port on a circumference centered on a rotation axis, wherein the valve plate has a first oil groove provided in an endless manner and a plurality of second oil grooves provided in an outer circumferential portion of the high-pressure side port and the low-pressure side port, the plurality of second oil grooves being provided in an opening portion of the cylinder toward the end face of the cylinder, the valve plate being configured such that the high-pressure side port and the low-pressure side port alternately communicate with a cylinder bore provided in the cylinder in a state of abutting against the end face of the cylinder, and a plurality of outer ring oil grooves are provided in a portion of the outer circumferential portion of the second oil grooves abutting against the end face of the cylinder, the portion being located at least on a downstream side of the relative rotation, the plurality of outer ring oil grooves being communicated with the first oil grooves, and the plurality of outer ring oil grooves being provided in a large proportion to the outer ring opening portion of the cylinder facing the downstream side of the opening portion of the rotation axis. According to the present invention, the oil in the first oil groove is supplied to the outer ring region through the outer ring oil groove, and thus an oil film between the port plate and the end face of the cylinder is ensured even at high pressure and high speed, and problems such as seizing and abrasion can be avoided. Further, the outer ring oil groove is provided such that the ratio of the opening area thereof with respect to the cylinder end surface is such that the downstream side of the relative rotation, which is not easily reached by the oil of the second oil groove, is larger than the upstream side of the relative rotation, which is easily reached by the oil of the second oil groove. In other words, the portion formed as the outer ring region on the upstream side of the relative rotation ensures the state of the sliding portion with the cylinder. Therefore, there is no risk that the rotation of the cylinder becomes unstable due to the provision of the outer ring oil groove, and high-pressure and high-speed operation can be realized. Drawings Fig. 1A is a cross-sectional vie