Hydraulic pump/motor

Patent metadata

Field	Value
Publication number	US-10018174-B2
Application number	US-201415027322-A
Country	US
Kind code	B2
Filing date	Oct 31, 2014
Priority date	Oct 31, 2014
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

An axial-type hydraulic pump/motor in which a cylinder block with a plurality of cylinder bores formed around a rotation axis slides with respect to a valve plate that has a valve plate discharge port and a valve plate suction port, and controls the amount of reciprocation of a piston in each cylinder bore depending on the inclination of a swash plate. Based on the rotational direction of the cylinder block, an opening shape of an end portion on the front side in the rotational direction of a cylinder port and an opening shape of an end portion on the rear side in the rotational direction of the valve plate suction port PB 1 have the same shape or partially have the same shape.

First claim

The invention claimed is:

1. A hydraulic pump/motor in which a cylinder block with a plurality of cylinder bores formed around a rotation axis slides with respect to a valve plate including a high-pressure port and a low-pressure port, and which controls an amount of reciprocation of a piston in each of the cylinder bores depending on an inclination of a swash plate,
wherein a first opening shape of the high-pressure port and a second opening shape of the low-pressure port extend circumferentially on a same arc centered around the rotation axis and are annular band shapes that do not include a top dead point and a bottom dead point,
a third opening shape of a cylinder port in each of the cylinder bores extends circumferentially on a same arc where the high-pressure port and the low-pressure port are disposed, and is an annular band shape that does not communicate with the high-pressure port and the low-pressure port at least when positioned at the top dead point and the bottom dead point,
a fourth opening shape of an end portion on a front side of the cylinder port and a fifth opening shape of an end portion of a rear side of the cylinder port with reference to a rotational direction of the cylinder block are circular convex shapes,
a sixth opening shape of an end portion on a front side of the high-pressure port and a seventh opening shape of an end portion on a rear side of the high-pressure port in a rotational direction of the high-pressure port, and an eighth opening shape of an end portion on a front side of the low-pressure port in a rotational direction of the low-pressure port are circular convex shapes,
a ninth opening shape of an end portion on a rear side of the low-pressure port in the rotational direction of the low-pressure port is a circular concave shape, and
the fourth opening shape of the end portion on the front side of the cylinder port in a rotational direction of the cylinder port and the ninth opening shape of the end portion on the rear side of the low-pressure port in the rotational direction of the low-pressure port are a same shape.

2. A hydraulic pump in which a cylinder block with a plurality of cylinder bores formed around a rotation axis slides with respect to a valve plate including a high-pressure port and a low-pressure port, and which controls an amount of reciprocation of a piston in each of the cylinder bores depending on an inclination of a swash plate,
wherein a first opening shape of the high-pressure port and a second opening shape of the low-pressure port extend circumferentially on a same arc centered around the rotation axis and are an annular band shape that does not include a top dead point and a bottom dead point,
a third opening shape of a cylinder port in each of the cylinder bores extends circumferentially on the same arc where the high-pressure port and the low-pressure port are disposed, and is an annular band shape that does not communicate with the high-pressure port and the low-pressure port at the top dead point and the bottom dead point,
a fourth opening shape of an end portion on a front side of the cylinder port and a fifth opening shape of an end portion of a rear side of the cylinder port with reference to a rotational direction of the cylinder block are circular convex shapes,
a sixth opening shape of an end portion on a front side of the high-pressure port in a rotational direction of the high-pressure port is a circular concave shape,
a seventh opening shape of an end portion on a rear side of the high-pressure port in the rotational direction of the high-pressure port is a circular convex shape,
an eighth opening shape of an end portion on a front side of the low-pressure port and a ninth opening shape of an end portion of a rear side of the low-pressure port in a rotational direction of the low-pressure port are circular concave shapes,
the fourth opening shape of the end portion on the front side of the cylinder port in a rotational direction of the cylinder port and the ninth opening shape of the end portion on the rear side of the low-pressure port in the rotational direction of the low-pressure port are a same shape,
the fifth opening shape of the end portion on the rear side of the cylinder port in the rotational direction of the cylinder port, the eighth opening shape of the end portion on the front side of the low-pressure port in the rotational direction of the low-pressure port, and the sixth opening shape of the end portion on the front side of the high-pressure port in the rotational direction of the high-pressure port are a same shape,
the valve plate further includes a residual pressure release port which communicates with each of the cylinder bores after each of the cylinder bores pass the top dead point and before each of the cylinder bores communicate with the low-pressure port, and
a first opening portion of the end portion on the rear side of the low-pressure port in the rotational direction of the low-pressure port is separated from the top dead point
so as to communicate with a second opening portion of an end portion on the front side of the cylinder port in the rotational direction of the cylinder port after passing a rotation assist region where rotation of the cylinder block is assisted by a pressure oil inside each of the cylinder bores from a top dead point position of the cylinder port and a residual pressure release region where a pressure inside each of the cylinder bores is decreased by a communication between the residual pressure release port and each of the cylinder bores and
so as to shift to a suction process.

3. A hydraulic pump in which a cylinder block with a plurality of cylinder bores formed around a rotation axis slides with respect to a valve plate including a high-pressure port and a low-pressure port, and which controls an amount of reciprocation of a piston in each of the cylinder bores depending on an inclination of a swash plate,
wherein a first opening shape of the high-pressure port and a second opening shape of the low-pressure port extend circumferentially on a same arc centered around the rotation axis and are an annular band shape that does not include a top dead point and a bottom dead point,
a third opening shape of a cylinder port in each of the cylinder bores extends circumferentially on the same arc where the high-pressure port and the low-pressure port are disposed, and is an annular band shape that does not communicate with the high-pressure port and the low-pressure port at the top dead point and the bottom dead point,
a fourth opening shape of an end portion on a front side of the cylinder port and a fifth opening shape of an end portion of a rear side of the cylinder port with reference to a rotational direction of the cylinder block are circular convex shapes,
a combination of eighth and ninth opening shapes of end portions on a front side and a rear side of the low-pressure port in a rotational direction of the low-pressure port differs from a combination of sixth and seventh opening shapes of end portions on a front side and a rear side of the high-pressure port in a rotational direction of the high-pressure port,
at least one of the eighth opening shape of the end portion on the front side and the ninth opening shape of the end portion on the rear side of the low-pressure port is a circular concave shape,
when the eighth opening shape of the end portion of the front side of the low-pressure port in the rotational direction of the low-pressure port is a circular concave shape, the fifth opening shape of the end portion of the rear side of the cylinder port in a rotational direction of the cylinder port and the eighth opening shape of the end portion of the front side of the low-pressure port in the rotational direction of the low-pressure port are a same shape,
when the ninth opening shape of the end portion of th

Assignees

• Komatsu Mfg Co Ltd

Inventors

• Iida Takeo
• Usami Hideaki
• Hasegawa Seiichi

Classifications

• F04B1/2021

  characterised by the contact area between cylinder barrel and valve plate · CPC title

• F04B1/2042

  Valves · CPC title

• F03C1/0647 Primary

  Particularities in the contacting area between cylinder barrel and valve plate · CPC title

• F03C1/0652

  Cylinders · CPC title

• F04B1/2035

  Cylinder barrels · CPC title