Pump apparatus, power steering apparatus and assembly method of housing

A power steering apparatus comprising:

• a power cylinder which is for a steering assist, and which includes a piston, and first and second pressure chambers formed within the power cylinder on both sides of the piston;
• and
• a reversible pump apparatus which is driven by an electromotive motor, which includes first and second suction discharge openings connected, respectively, with the first and second pressure chambers, and which is arranged to supply a hydraulic fluid selectively to the first and second pressure chambers by controlling the electromotive motor in accordance with a steering torque inputted from a steering wheel;
• the pump apparatus including;
• a first housing member which includes a first drive shaft insertion hole extending in an axial direction;
• a second housing member which includes a second drive shaft insertion hole extending in the axial direction, and which is disposed to confront the first housing member;
• a pump element disposed between the first housing member and the second housing member, and arranged to suck and discharge the hydraulic fluid by rotating;
• a pump drive shaft rotatably inserted into the first drive shaft insertion hole and the second drive shaft insertion hole, connected with a motor drive shaft of the electromagnetic motor, and arranged to drive and rotate the pump element;
• a first abutment portion formed in the second housing member, and arranged to position the second housing member with respect to the first housing member in a radial direction by abutting, from a radially inside direction of the first housing member, on a first positioning protruding portion protruding from the first housing member toward the second housing member;
• a second abutment portion formed in the second housing member, and arranged to position the second housing member with respect to the first housing member in a swing direction of the second housing member about the first positioning protruding portion, by abutting, in the swing direction, on a second positioning protruding portion protruding from the first housing member toward the second housing member;
• and
• a joining member joining the first housing member and the second housing member,
• the first and second drive shaft insertion holes being previously co-processed in a state in which the first housing member and the second housing member are relatively positioned by abutments between the first and second positioning protruding portions and the first and second abutment portions, and
• the joining member joining the first housing member and the second housing member in a state in which the first housing member and the second housing member are relatively positioned by the abutments of the first and second positioning protruding portions and the first and second abutment portions so as to re-create a relative position between the first housing member and the second housing member at the co-processing.

A method of assembling a housing including a first housing member, a second housing member which is disposed to confront the first housing member, and which receives an inner member between the first housing member and the second housing member, a first abutment portion formed in the second housing member, and arranged to position the second housing member with respect to the first housing member in an abutment direction perpendicular to a separating direction of the first and second housing members, by abutting, in the abutment direction, on a first positioning protruding portion protruding from the first housing member toward the second housing member, and a second abutment portion formed in the second housing member, and arranged to position the second housing member with respect to the first housing member in a swing direction of the second housing member about the first positioning protruding portion, by abutting, in the swing direction, on a second positioning protruding portion protruding from the first housing member toward the second housing member, the first and second housing members being joined while the inner member is received between the first housing members after the first housing member is formed with a first processing portion and the second housing member is formed with a second processing portion, the assembly method comprising:

• a first assembly step of relatively positioning the first housing member and the second housing member by abutments of the first and second positioning protruding portions and the first and second abutment portions while the first housing member and the second housing member are assembled without receiving the inner member, and joining the first and second housing members in this state;
• a processing step of forming the first processing portion and the second processing portion in the first and second housing members by co-processing the first and second housing members after the first assembly step;
• a disassembly step of disassembling the first and second housing members after the processing step;
• and
• a second assembly step of assembling the first and second housing members after receiving the inner member, abutting the first and second positioning protruding portions and the first and second abutment portions so as to re-create the relative position between the first and second housing members at the processing step, and joining the first and second housing members in this state.