Lubricating oil supply structure

Abstract

A housing supporting a rotational shaft and accommodating an axial piston member is provided with an oil reservoir space that faces at least one of the two end faces in the axial direction of the rotational shaft. The rotational shaft is provided with a rotational-shaft-side supply oil passage that includes an axial hole open to the oil reservoir space and an axial-piston-member lubricating oil hole having one end fluidly connected to the axial hole and the other end open to a portion of the external surface of the first rotational shaft that faces the axial piston member.

What is claimed is: 
     
         1 . A lubricating oil supply structure applicable to an axial piston device including a rotational shaft, an axial piston member supported by the rotational shaft in a relatively non-rotatable manner with respect thereto and a housing accommodating the axial piston member wherein the rotational shaft supports the axial piston device at a central part in an axial direction and is supported at one end side and the other end side in the axial direction by first-end-side and second-end-side bearing holes formed in the housing in a rotatable manner around the axis line, the lubricating oil supply structure comprising,
 an oil reservoir space formed in the housing so as to be capable of receiving oil from an oil source and face at least one of the two end faces in the axial direction of the rotational shaft, and a rotational-shaft-side supply oil passage that is formed in the rotational shaft,   wherein the rotational-shaft-side supply oil passage has an axial hole open to an end face of the rotational shaft that faces the oil reservoir space among the two end faces in the axial direction of the rotational shaft and an axial-piston-member lubricating oil hole having one end fluidly connected to the axial hole and the other end open to a portion of the external surface of the first rotational shaft that faces the axial piston member.   
     
     
         2 . The lubricating oil supply structure according to  claim 1 , wherein the rotational-shaft-side supply oil passage has a lubricating oil hole for bearing member having one end fluidly connected to the axial hole and the other end open to at least one of portions of the external surface of the rotational shaft that are located in the first- and second-end-side bearing holes, respectively. 
     
     
         3 . The lubricating oil supply structure according to  claim 2 , wherein the lubricating oil hole for bearing member includes a first-end-side lubricating oil hole that is fluidly connected to the axial hole and open to the portion of the external surface of the rotational shaft located in the first-end-side bearing hole, and a second-end-side lubricating oil hole that is fluidly connected to the axial hole and open to the portion of the external surface of the rotational shaft located in the second-end-side bearing hole. 
     
     
         4 . The lubricating oil supply structure according to  claim 3 ,
 wherein the rotational shaft includes first and second rotational shafts coaxially disposed to each other,   wherein the axial piston member includes first and second axial piston members supported by the first and second rotational shafts, respectively,   wherein the first and second rotational shafts are disposed such that there is a gap between the end face on the first end side of the first rotational shaft and the end face on the second end side of the second rotational shaft, the gap being used as the oil reservoir space,   wherein the axial hole includes first and second axle holes that are fluidly connected to the oil reservoir space and formed in the first and second rotational shafts, respectively, and   wherein the axial-piston-member lubricating oil hole includes a first-axial-piston-member lubricating oil hole having one end fluidly connected to the first axial hole and the other end open to a portion of the external surface of the first rotational shaft that faces the first axial piston member, and a second-axial-piston-member lubricating oil hole having one end fluidly connected to the second axial hole and the other end open to a portion of the external surface of the second rotational shaft that faces the second axial piston member.   
     
     
         5 . The lubricating oil supply structure according to  claim 3 ,
 wherein the rotational shaft includes first and second rotational shafts arranged parallel to each other to have axis lines mutually displaced,   wherein the axial piston member includes first and second axial piston members supported by the first and second rotational shafts, respectively,   wherein the oil reservoir space includes a first oil reservoir space formed in the housing so as to be capable of receiving an oil from the oil source and face at least one of the end faces on one side and the other side in the axis direction of the first rotational shaft, and a second oil reservoir space formed in the housing so as to be capable of receiving an oil from the oil source and face at least one of the end faces on one side and the other side in the axis direction of the second rotational shaft,   wherein the axial hole includes a first axle hole formed in the first rotational shaft so as to be fluidly connected to the first oil reservoir space and a second axle hole formed in the second rotational shaft so as to be fluidly connected to the second oil reservoir space, and   wherein the axial-piston-member lubricating oil hole includes a first-axial-piston-member lubricating oil hole having one end fluidly connected to the first axial hole and the other end open to a portion of the external surface of the first rotational shaft that faces the first axial piston member and a second-axial-piston-member lubricating oil hole having one end fluidly connected to the second axial hole and the other end open to a portion of the external surface of the second rotational shaft that faces the second axial piston member.   
     
     
         6 . The lubricating oil supply structure according to  claim 2 ,
 wherein the rotational shaft includes first and second rotational shafts coaxially disposed to each other,   wherein the axial piston member includes first and second axial piston members supported by the first and second rotational shafts, respectively,   wherein the first and second rotational shafts are disposed such that there is a gap between the end face on the first end side of the first rotational shaft and the end face on the second end side of the second rotational shaft, the gap being used as the oil reservoir space,   wherein the axial hole includes first and second axle holes that are fluidly connected to the oil reservoir space and formed in the first and second rotational shafts, respectively, and   wherein the axial-piston-member lubricating oil hole includes a first-axial-piston-member lubricating oil hole having one end fluidly connected to the first axial hole and the other end open to a portion of the external surface of the first rotational shaft that faces the first axial piston member, and a second-axial-piston-member lubricating oil hole having one end fluidly connected to the second axial hole and the other end open to a portion of the external surface of the second rotational shaft that faces the second axial piston member.   
     
     
         7 . The lubricating oil supply structure according to  claim 2 ,
 wherein the rotational shaft includes first and second rotational shafts arranged parallel to each other to have axis lines mutually displaced,   wherein the axial piston member includes first and second axial piston members supported by the first and second rotational shafts, respectively,   wherein the oil reservoir space includes a first oil reservoir space formed in the housing so as to be capable of receiving an oil from the oil source and face at least one of the end faces on one side and the other side in the axis direction of the first rotational shaft, and a second oil reservoir space formed in the housing so as to be capable of receiving an oil from the oil source and face at least one of the end faces on one side and the other side in the axis direction of the second rotational shaft,   wherein the axial hole includes a first axle hole formed in the first rotational shaft so as to be fluidly connected to the first oil reservoir space and a second axle hole formed in the second rotational shaft so as to be fluidly connected to the second oil reservoir space, and   wherein the axial-piston-member lubricating oil hole includes a first-axial-piston-member lubricating oil hole having one end fluidly connected to the first axial hole and the other end open to a portion of the external surface of the first rotational shaft that faces the first axial piston member and a second-axial-piston-member lubricating oil hole having one end fluidly connected to the second axial hole and the other end open to a portion of the external surface of the second rotational shaft that faces the second axial piston member.   
     
     
         8 . The lubricating oil supply structure according to  claim 1 ,
 wherein the rotational shaft includes first and second rotational shafts coaxially disposed to each other,   wherein the axial piston member includes first and second axial piston members supported by the first and second rotational shafts, respectively,   wherein the first and second rotational shafts are disposed such that there is a gap between the end face on the first end side of the first rotational shaft and the end face on the second end side of the second rotational shaft, the gap being used as the oil reservoir space,   wherein the axial hole includes first and second axle holes that are fluidly connected to the oil reservoir space and formed in the first and second rotational shafts, respectively, and   wherein the axial-piston-member lubricating oil hole includes a first-axial-piston-member lubricating oil hole having one end fluidly connected to the first axial hole and the other end open to a portion of the external surface of the first rotational shaft that faces the first axial piston member, and a second-axial-piston-member lubricating oil hole having one end fluidly connected to the second axial hole and the other end open to a portion of the external surface of the second rotational shaft that faces the second axial piston member.   
     
     
         9 . The lubricating oil supply structure according to  claim 8 , wherein the housing has a port block including the reservoir space, a first housing body removably connected to the port block to form a first accommodating space accommodating the first axial piston member, and a second housing body removably connected to the port block to form a second accommodating space that is positioned opposite to the first accommodating space with reference to the port block and accommodates the second axial piston member. 
     
     
         10 . The lubricating oil supply structure according to  claim 8 ,
 wherein the first rotational shaft functions as a pump shaft that is operatively connected to a driving source, and the second rotational shaft functions as a motor shaft that outputs rotative power,   wherein at least one of the first axial piston member functioning as a hydraulic pump and the second axial piston member functioning as a hydraulic motor is a variable-volume type,   wherein the housing is formed with a pair of hydraulic oil passages that fluidly connects the first and second axial piston members so as to form a closed circuit including them, and a charge oil passage for replenishing the closed circuit with hydraulic oil, and   wherein a part of oil in the charge oil passage is supplied to the oil reservoir space.   
     
     
         11 . The lubricating oil supply structure according to  claim 10 ,
 wherein the first axial piston member includes a first cylinder block supported by the first rotational shaft in a relatively non-rotatable manner with respect thereto and having a plurality of cylinder holes arranged around the axis line of the first rotational shaft, and a plurality of first pistons accommodated in the plurality of the cylinder holes in a reciprocating manner, free ends of the plurality of first pistons being directly or indirectly come into contact with a first swash plate provided in the first axial piston device to define the volume of the first axial piston member,   wherein the second axial piston member includes a second cylinder block supported by the second rotational shaft in a relatively non-rotatable manner with respect thereto and having a plurality of cylinder holes arranged around the axis line of the second rotational shaft, and a plurality of second pistons accommodated in the plurality of the cylinder holes in a reciprocating manner, free ends of the plurality of second pistons being directly or indirectly come into contact with a second swash plate provided in the second axial piston device to define the volume of the second axial piston member,   wherein the other end of the first-axial-piston-member lubricating oil hole is open to a portion of the external surface of the first rotational shaft that is close to a region where the free ends of the plurality of first pistons are come into contact with the first movable swash plate, and   wherein the other end of the second-axial-piston-member lubricating oil hole is open to a portion of the external surface of the second rotational shaft that is close to a region where the free ends of the plurality of second pistons are come into contact with the second movable swash plate.   
     
     
         12 . The lubricating oil supply structure according to  claim 8 ,
 wherein the first axial piston member includes a first cylinder block supported by the first rotational shaft in a relatively non-rotatable manner with respect thereto and having a plurality of cylinder holes arranged around the axis line of the first rotational shaft, and a plurality of first pistons accommodated in the plurality of the cylinder holes in a reciprocating manner, free ends of the plurality of first pistons being directly or indirectly come into contact with a first swash plate provided in the first axial piston device to define the volume of the first axial piston member,   wherein the second axial piston member includes a second cylinder block supported by the second rotational shaft in a relatively non-rotatable manner with respect thereto and having a plurality of cylinder holes arranged around the axis line of the second rotational shaft, and a plurality of second pistons accommodated in the plurality of the cylinder holes in a reciprocating manner, free ends of the plurality of second pistons being directly or indirectly come into contact with a second swash plate provided in the second axial piston device to define the volume of the second axial piston member,   wherein the other end of the first-axial-piston-member lubricating oil hole is open to a portion of the external surface of the first rotational shaft that is close to a region where the free ends of the plurality of first pistons are come into contact with the first movable swash plate, and   wherein the other end of the second-axial-piston-member lubricating oil hole is open to a portion of the external surface of the second rotational shaft that is close to a region where the free ends of the plurality of second pistons are come into contact with the second movable swash plate.   
     
     
         13 . The lubricating oil supply structure according to  claim 12 ,
 wherein the first swash plate is a movable swash plate including a base portion supported by the housing in a rotatable manner around a rocking axis perpendicular to the first rotational shaft, and a swash plate body supported by the base portion and directly or indirectly engaged with the free ends of the plurality of first pistons, and   wherein the housing is formed with a lubricating oil hole for the first swash plate having one end side fluidly connected to the oil source and the other end side open to a supporting hole that is formed in the housing so as to support the base portion.   
     
     
         14 . The lubricating oil supply structure according to  claim 1 ,
 wherein the rotational shaft includes first and second rotational shafts arranged parallel to each other to have axis lines mutually displaced,   wherein the axial piston member includes first and second axial piston members supported by the first and second rotational shafts, respectively,   wherein the oil reservoir space includes a first oil reservoir space formed in the housing so as to be capable of receiving an oil from the oil source and face at least one of the end faces on one side and the other side in the axis direction of the first rotational shaft, and a second oil reservoir space formed in the housing so as to be capable of receiving an oil from the oil source and face at least one of the end faces on one side and the other side in the axis direction of the second rotational shaft,   wherein the axial hole includes a first axle hole formed in the first rotational shaft so as to be fluidly connected to the first oil reservoir space and a second axle hole formed in the second rotational shaft so as to be fluidly connected to the second oil reservoir space, and   wherein the axial-piston-member lubricating oil hole includes a first-axial-piston-member lubricating oil hole having one end fluidly connected to the first axial hole and the other end open to a portion of the external surface of the first rotational shaft that faces the first axial piston member and a second-axial-piston-member lubricating oil hole having one end fluidly connected to the second axial hole and the other end open to a portion of the external surface of the second rotational shaft that faces the second axial piston member.   
     
     
         15 . The lubricating oil supply structure according to  claim 14 , wherein the housing includes a port block and a housing body removably connected to the port block to form an accommodating space accommodating the first and second axial piston members. 
     
     
         16 . The lubricating oil supply structure according to  claim 14 ,
 wherein the first rotational shaft functions as a pump shaft that is operatively connected to a driving source, and the second rotational shaft functions as a motor shaft that outputs rotative power,   wherein at least one of the first axial piston member functioning as a hydraulic pump and the second axial piston member functioning as a hydraulic motor is a variable-volume type,   wherein the housing is formed with a pair of hydraulic oil passages that fluidly connects the first and second axial piston members so as to form a closed circuit including them, and a charge oil passage for replenishing the closed circuit with hydraulic oil, and   wherein a part of oil in the charge oil passage is supplied to the oil reservoir space.   
     
     
         17 . The lubricating oil supply structure according to  claim 14 ,
 wherein the first axial piston member includes a first cylinder block supported by the first rotational shaft in a relatively non-rotatable manner with respect thereto and having a plurality of cylinder holes arranged around the axis line of the first rotational shaft, and a plurality of first pistons accommodated in the plurality of the cylinder holes in a reciprocating manner, free ends of the plurality of first pistons being directly or indirectly come into contact with a first swash plate provided in the first axial piston device to define the volume of the first axial piston member,   wherein the second axial piston member includes a second cylinder block supported by the second rotational shaft in a relatively non-rotatable manner with respect thereto and having a plurality of cylinder holes arranged around the axis line of the second rotational shaft, and a plurality of second pistons accommodated in the plurality of the cylinder holes in a reciprocating manner, free ends of the plurality of second pistons being directly or indirectly come into contact with a second swash plate provided in the second axial piston device to define the volume of the second axial piston member,   wherein the other end of the first-axial-piston-member lubricating oil hole is open to a portion of the external surface of the first rotational shaft that is close to a region where the free ends of the plurality of first pistons are come into contact with the first movable swash plate, and   wherein the other end of the second-axial-piston-member lubricating oil hole is open to a portion of the external surface of the second rotational shaft that is close to a region where the free ends of the plurality of second pistons are come into contact with the second movable swash plate.