Liquid pressure rotary machine

Patent metadata

Field	Value
Publication number	US-10920757-B2
Application number	US-201916445740-A
Country	US
Kind code	B2
Filing date	Jun 19, 2019
Priority date	Jul 12, 2018
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

A liquid pressure rotary machine in which a rotation delay of a retainer with respect to a cylinder block is reduced and contact of pistons placed between the retainer and the cylinder block with peripheral members is suppressed is provided.
A piston pump includes a rotation shaft, a cylinder block, piston heads, piston rods, a retainer, a swash plate, and a tilt adjustment mechanism. When the tilt adjustment mechanism swings the swash plate, a discharge amount of the piston pump becomes variable. The retainer to be rotated together with the piston heads and the piston rods is supported by a retainer bushing provided in the rotation shaft. By engaging ball pins of the retainer bushing with spherical surface pin grooves of the retainer, the retainer and the retainer bushing are integrally rotatable about the center axis of the rotation shaft and the retainer is swung about the spherical surface center.

First claim

What is claimed is:

1. A variable capacity type liquid pressure rotary machine comprising: a housing; a rotation shaft rotatably and axially supported by the housing; a cylinder block including plural cylinders arranged and spaced from each other about the rotation shaft, the cylinder block to be rotated about a center axis of the rotation shaft integrally with the rotation shaft; plural pistons respectively housed in the plural cylinders of the cylinder block, the pistons performing reciprocating motion in accordance with rotation of the cylinder block along an axial direction of the cylinder block; a retainer bushing including a bushing outer peripheral surface having a spherical surface shape projected radially outward in relation to the rotation shaft, the retainer bushing being supported on the rotation shaft so as to be rotatable about the center axis together with the rotation shaft; a retainer including a retainer inner peripheral surface which is formed in a recessed spherical surface shape arranged to oppose the bushing outer peripheral surface, the retainer being supported by the retainer bushing so as to be swingable about an orthogonal axis which is orthogonal to the center axis of the rotation shaft; plural piston rods arranged to extend in the axial direction, the piston rods respectively connect the plural pistons and the retainer and rotate the retainer about the center axis in conjunction with rotation of the cylinder block about the center axis; a swash plate arranged to oppose the retainer on an axially opposite side to the cylinder block, the swash plate being supported by the housing so as to be swingable about the orthogonal axis; a thrust placed between the swash plate and the retainer in an axial direction, the thrust bearing that supports the retainer in such a manner that the retainer is rotatable about the center axis with respect to the swash plate; and a tilt adjustment mechanism that, by swinging the swash plate about the orthogonal axis, swings the retainer about the orthogonal axis through the thrust bearing while relatively displacing the retainer inner peripheral surface relative to the bushing outer peripheral surface, and adjusts an axially moving amount of the pistons, wherein the retainer bushing has at least one projecting portion projecting radially outward from the bushing outer peripheral surface and having a leading end portion in a radially outward direction formed in a spherical surface shape, at least one groove portion extending along a direction in which the retainer is swung about the orthogonal axis is formed on the retainer inner peripheral surface of the retainer, and by engaging the at least one projecting portion with the at least one groove portion, the retainer and the retainer bushing are integrally rotatable about the center axis, and by moving the at least one projecting portion in the at least one groove portion, the retainer is swingable about the orthogonal axis.

2. The liquid pressure rotary machine according to claim 1 , wherein
the at least one projecting portion includes plural projecting portions arranged and spaced from each other along a rotation direction of the rotation shaft, and
the at least one groove portion includes plural groove portions arranged and spaced from each other along the rotation direction.

3. The liquid pressure rotary machine according to claim 2 , wherein
the plural groove portions are formed in a recessed circular shape when seen in a section orthogonal to the center axis, and
a curvature of the circular shape of the plural groove portions is set to be the same as a curvature of the spherical surface shape of the leading end portions of the plural projecting portions.

4. The liquid pressure rotary machine according to claim 2 , wherein the retainer has an even number of the projecting portions arranged about the center axis at equal intervals, and the retainer inner peripheral surface is formed with the same number of the groove portions as the plural projecting portions, the groove portions being arranged about the center axis at equal intervals.

5. The liquid pressure rotary machine according to claim 4 , wherein in the cylinder block, an odd number of the pistons are arranged about the center axis at equal intervals, and the same number of the piston rods as the pistons are provided in the cylinder block, the piston rods being arranged about the center axis at equal intervals.

Assignees

• Kobe Steel Ltd

Inventors

• Morita Kei
• Sugano Naoki
• Maekawa Satoshi

Classifications

• F03C1/002

  details; components parts · CPC title

• F04B1/124

  Pistons · CPC title

• F03C1/2462

  the rotary cylinder being provided with only one piston reciprocating within this cylinder · CPC title

• F04B1/2085 Primary

  Bearings for swash plates or driving axles · CPC title

• F04B1/30

  of machines or pumps with rotary cylinder blocks · CPC title