Axial piston device

• US 7,708,531 B2
• Filed: 09/01/2004
• Issued: 05/04/2010
• Est. Priority Date: 09/09/2003
• Status: Active Grant

• Current Assignee: Kanzaki Kokyukoki Mfg. Co., Ltd. (Yanmar Holdings Co., Ltd.)
• Original Assignee: Kanzaki Kokyukoki Mfg. Co., Ltd. (Yanmar Holdings Co., Ltd.)
• Inventors: Kawakami, Manabu, Sakikawa, Shigenori
• Primary Examiner(s): Freay; Charles G
• Assistant Examiner(s): COMLEY, ALEXANDER BRYANT
• Application Number:
  US10/931,095
• Publication Number:
  US 20050053478A1
• Time in Patent Office: 2,071 Days
• Field of Search: 417/269, 915/05, 92/122, 921/28, 92/86, 92/82, 604/89, 604/68
• US Class Current: 417/269
• CPC Class Codes: F04B 1/2014 Details or component parts
• CPC Class Codes: F04B 1/2035 Cylinder barrels
• CPC Class Codes: F04B 23/106 being an axial piston pump

Abstract

There is provided an axial piston device that includes a housing, a rotary shaft, a cylinder block, and a piston. The housing includes a housing body opened at a first end thereof and a plate disposed at the first end of the housing body. The rotary shaft is rotatably supported about an axis by the housing body and the plate. The cylinder block is rotated together with the rotary shaft and is accommodated inside the housing. The piston is accommodated in the cylinder block in slidable a manner in an axial direction. Furthermore, the plate is provided with a pair of first oil passages having first ends communicating with a discharge port and a suction port of the cylinder block and second ends opened to the surface of the plate, and a drain oil passage for allowing at least one of the first oil passages to communicate with an oil sump. The drain oil passage is provided with a rotary valve which can selectively switch a shutoff position at which the drain oil passage is shut off and a communication position at which the drain oil passage is communicated.

Claims

1. An axial piston device comprising:

(a) a housing including a housing body opened at a first end thereof and a plate disposed at the first end of the housing body;

(b) a rotary shaft rotatably supported about an axis by said housing body and said plate;

(c) a cylinder block rotated together with said rotary shaft, the cylinder block being accommodated inside said housing; and

(d) a piston accommodated in said cylinder block in a slidable manner along an axial direction, wherein

(e) said plate is provided with a pair of first oil passages having first ends fluidly connected to a discharge port and a suction port of said cylinder block and second ends opened to an outer surface of the plate, and a drain oil passage for fluidly connecting the pair of first oil passages to an internal space of the housing that functions as an oil sump,

(f) said pair of first oil passages extends in a direction orthogonal to an axis line of the rotary shaft and are parallel to each other, sandwiching the rotary shaft therebetween,

(g) said drain oil passage includes a single substantially linear cross oil passage that fluidly connects the pair of first oil passages, and a connecting oil passage having a first end fluidly connected to the cross oil passage and a second end opposite from the first end,

(h) said plate is provided with a rotary valve which can selectively take a shutoff position at which the drain oil passage is shut off and a communication position at which the drain oil passage is communicated, and

(i) the rotary valve is inserted in a rotatable manner around its axis line in a disposing hole that is formed in the plate so as to be positioned between the pair of first oil passages with and parallel thereto, and is configured so as to selectively take the shutoff position and the communication position by being rotated around its axis line without a movement along the axis line,

(j) there is provided a valve plate between the plate and the cylinder block, the valve plate fluidly connecting the discharge port and the suction port of the cylinder block to the pair of first oil Passages, respectively, and supporting the cylinder block in a rotatable manner about the rotary shaft,

(k) a surface of the plate that is faced to the internal space of the housing is formed with a groove that is opened toward the valve plate,

(l) the second end of the connecting oil passage of the drain oil passage is fluidly connected to the groove, and

(m) the groove extends further than the valve plate in a radial direction with the rotary shaft as a reference.

2. An axial piston device according to claim 1, further comprising:

a pump body to be driven by said rotary shaft; and

a pair of second oil passages communicating with the discharge port and the suction port of said pump body, respectively, wherein

at least a part of oil, which is supplied to a hydraulic device from the discharge port of said pump body via one of said second oil passages and is returned to the suction port of said pump body via the other one of said second oil passages, is introduced into said pair of first oil passages.

3. An axial piston device according to claim 1, wherein

said housing is configured in such a manner as to surround said plate in addition to said cylinder block, and

the second ends of said the pair of first oil passages are fluid-connected to a conduit member supported by the housing astride inward and outward of said housing.