Tandem pump

Abstract

An apparatus comprising a tandem pump which includes first and second pump sections driven by a rotation shaft, and a housing defining a pump receiving portion including a first pump chamber receiving the first pump section and a second pump chamber receiving the second pump section. The first and second pump chambers are separated by a partition. The partition is positioned by the housing at least in the axial direction of the rotation shaft.

1 . An apparatus comprising a tandem pump which comprises:
 a rotation shaft extending in an axial direction;   first and second pump sections driven by the rotation shaft;   a housing defining a pump receiving portion including a first pump chamber receiving the first pump section and a second pump chamber receiving the second pump section; and   a partition separating the first and second pump chambers from each other, the partition being positioned in the axial direction by the housing.   
   
   
       2 . The apparatus as claimed in  claim 1 , wherein the housing is arranged to regulate rotation of the partition. 
   
   
       3 . The apparatus as claimed in  claim 2 , wherein the housing includes a main housing member including the pump receiving portion and a cover member closing the pump receiving portion. 
   
   
       4 . The apparatus as claimed in  claim 3 , wherein the partition includes a plate member which is separate from the housing and which includes an outer circumferential portion clamped between the housing main member and the cover member so that the position of the partition is fixed by being clamped. 
   
   
       5 . The apparatus as claimed in  claim 4 , wherein the main housing member includes a surrounding wall surrounding the pump receiving portion including a first portion having a smaller sectional size, a second portion having a larger sectional size greater than the smaller sectional size, and a step which is formed between the first and second portions of the pump receiving portion and which is arranged to abut against the plate member of the partition so that the plate member is clamped between the step and the cover member. 
   
   
       6 . The apparatus as claimed in  claim 3 , wherein the housing includes an internally threaded portion formed inside the pump receiving portion, and the partition is a plate member which is separate from the housing, the plate member including an externally threaded portion which is formed on an outer circumference of the plate member and which is screwed in the internally threaded portion of the housing so that the position of the plate member is fixed. 
   
   
       7 . The apparatus as claimed in  claim 6 , wherein the main housing member includes a surrounding wall which surrounds the pump receiving portion including a first portion having a smaller sectional size, a second portion which has a larger sectional size greater than the smaller sectional size, and which includes the internally threaded portion formed in the second portion. 
   
   
       8 . The apparatus as claimed in  claim 5 , wherein the plate member of the partition includes a first plate member, a second plate member, and a seal groove which is formed between the first and second plate member and which receives a seal member surrounding the rotation shaft. 
   
   
       9 . The apparatus as claimed in  claim 3 , wherein the partition is formed as an integral part of the housing. 
   
   
       10 . The apparatus as claimed in  claim 9 , wherein the housing is made of an aluminum alloy, the first and second pump sections are made of a ferrous material, and a slide member is provided between the partition and each of the first and second pump sections. 
   
   
       11 . The apparatus as claimed in  claim 5 , wherein each of the first and second pump sections includes a driving gear drivingly connected with the rotation shaft and a driven gear engaged with the driving gear, the first pump section is interposed between a first side plate and a first side portion of the partition, the second pump section is interposed between a second side plate and a second side portion of the partition, and the first and second side portions are integral parts of the partition. 
   
   
       12 . The apparatus as claimed in  claim 3 , wherein the apparatus is further comprises:
 a wheel cylinder set including a first subset including a first wheel cylinder provided for braking a first wheel of a vehicle and a second subset including a second wheel cylinder provided for braking a second wheel of the vehicle; and   a hydraulic system including a first subsystem including a first control valve and connecting the first pump section with the first wheel cylinder to increase a fluid pressure of the first wheel cylinder, and a second subsystem including a second control valve and connecting the second pump section with the second wheel cylinder to increase a fluid pressure of the second wheel cylinder.   
   
   
       13 . The apparatus as claimed in  claim 1 , wherein the partition is arranged to separate the first and second pump chambers from each other in a liquid-tight manner to enable control of fluid pressures in the first and second pump chambers at different pressure levels, and the housing is arranged to fix the position of the partition in the axial direction and in a radial direction of the rotation axis. 
   
   
       14 . An apparatus comprising a tandem pump which comprises:
 a rotation shaft extending in an axial direction;   first and second pump sections driven by the rotation shaft;   a housing defining a pump receiving portion including a first pump chamber receiving the first pump section and a second pump chamber receiving the second pump section;   a partition located axially between the first and second pump chambers, and   volume change preventing means for preventing volume change of the first and second pump chambers by preventing the partition from being moved in the axial direction relative to the housing.