Power steering pump

Claim 2

In a pump of the type having a housing plate through which extends a shaft for rotatably driving a rotor carrying a plurality of slippers and wherein a cam ring surrounds the rotor and an upper pressure plate abuts the cam ring and rotor on the side opposite the housing plate, the improvement of a top plate adjacent said upper pressure plate and including a radially inwardly disposed recess in one face thereof bounded by axially extending walls, said recess comprising a reduced pressure area communicating with the pump-generated pressure at the upper pressure plate to receive said pressurized fluid, a guide member having a portion shaped for complemental fit in said recess and together with said top plate confining pressurized fluid in said reduced area recess, thereby optimizing the size of the pressure area acting on the upper pressure plate.

Claim 3

In a pump as defined in claim 1 and further characterized by a rigid shell made of metal formed in a cup-shaped configuration and having an end wall fastened to said guide member and having side walls surrounding the other portions of the pump with sufficient clearance to receive and retain a supply of inlet fluid therein, said shell member being flanged for sealing assembly to the housing plate.

Claim 4

In a pump as defined in claim 2 and further characterized by a flow control valve extending axially through the cam ring and the upper pressure plate, and having a line outlet passage formed in said top plate through which flow may be directed, said line outlet passage extending through said upper pressure plate, said cam ring and said housing plate.

Claim 5

A pump comprising, in combination, a housing plate through which a drive shaFt extends, a cam ring having a bore forming a pumping chamber and including an integral boss projecting to one side of said ring through which extends a valve passage for receiving a flow control valve, a rotor in said pumping chamber carrying a plurality of slipper pumping elements which are free to rock angularly and to move radially in following the bore contour of the adjoining wall of said pumping chamber, an upper pressure plate overlying said cam ring, rotor, and pumping elements and having ports formed therein through which pump-generated pressure is ported, said upper pressure plate having a correspondingly disposed and shaped boss overlying the cam ring boss, a top plate overlying said upper pressure plate and having a corresponding boss overlying the boss on said upper pressure plate, said top plate having a reduced area recess formed therein bounded by axial walls and having ports formed therein receiving fluid at pump-generated pressure, a guide member having a portion shaped to be received in said reduced area recess, thereby forming a reduced area pressure chamber for optimizing the size of the pressure area acting on the upper pressure plate, a steel shell drawn to a shape including an end wall for attachment to said guide member and side walls including a substantially cylindrical portion surrounding the cam ring, upper pressure plate and top plate and having a boss portion extending to one side sufficiently to enclose the other corresponding boss portions of said plate and said cam ring, said steel shell being flanged for attachment to said housing plate, and a housing shell attached to said guide member and having side walls sealingly engaged with said housing plate to form a reservoir surrounding said steel shell.

Claim 6

A pump comprising, in combination, a housing plate through which a drive shaFt extends, a cam ring having a bore forming a pumping chamber and including an integral boss projecting to one side of said ring through which extends a valve passage for receiving a flow control valve, a rotor in said pumping chamber carrying a plurality of slipper pumping elements which are free to rock angularly and to move radially in following the bore contour of the adjoining wall of said pumping chamber, an upper pressure plate overlying said cam ring, rotor, and pumping elements and having ports formed therein through which pump-generated pressure is ported, said upper pressure plate having a correspondingly disposed and shaped boss overlying the cam ring boss, a top plate overlying said upper pressure plate and having a corresponding boss overlying the boss on said upper pressure plate, said top plate having a reduced area recess formed therein bounded by axial walls and having ports formed therein receiving fluid at pump-generated pressure, a guide member having a portion shaped to be received in said reduced area recess, thereby forming a reduced area pressure chamber for optimizing the size of the pressure area acting on the upper pressure plate, a steel shell drawn to a shape including an end wall for attachment to said guide member and side walls including a substantially cylindrical portion surrounding the cam ring, upper pressure plate and top plate and having a boss portion extending to one side sufficiently to enclose the other corresponding boss portions of said plate and said cam ring, said steel shell being flanged for attachment to said housing plate, and a housing shell attached to said guide member and having side walls sealingly engaged with said housing plate to form a reservoir surrounding said steel shell.

Claim 7

A pump as defined in claim 4, said cam ring having an axially extending opening in said boss portion receiving a flow control valve, said cam ring having a pair of oppositely extending by-pass passages extending from said flow control valve to the area between said cam ring and said steel shell, said cam ring further including a pair of aspirator passages each intersecting a corresponding by-pass passage and extending generally radially outwardly through said boss portion, said steel shell having a pair of make-up openings communicating fluid from said reservoir into said aspirating passages.

Claim 8

A pump as defined in claim 5 and means for preventing supercharged fluid around the cam ring and inside the steel shell from interfering with the intake of fluid from the reservoir.

Claim 9

A pump as defined in claim 6 and further characterized by said last mentioned means comprising a baffle formed to fit said cam ring inside of the steel shell and upper and lower pressure plates, said baffle and said cam ring having a snap assembly means for connection of said baffle prior to assembly of the housing shell over the pump element stack, thereby to isolate the inlet zone inwardly of said steel shell from the reservoir area.

Claim 10

A pump as defined in claim 6 wherein said last mentioned means comprise rubber grommets disposed between said steel shell and said ring and having passages extending through said grommets directly communicating with said aspirator passages, thereby to isolate the inlet zone inwardly of said steel shell from the reservoir.