Hydraulic radial-type piston pump

A radial piston pump comprising:

• a pump housing;
• at least one elongated piston received within said housing;
• drive means for reciprocating said pistons;
• an elongated bushing mounted within said housing and having a bore slidingly receiving said piston;
• an elongated valve body, and means mounting said valve body at one end to said one end of said bushing, said valve body having a bore extending within said one end thereof;
• said piston projecting from said bushing bore into said valve body bore and being slidably received therein and having an end terminating in said valve body bore;
• a pressure chamber defined by said valve body bore and said piston end;
• an inlet passage formed in said piston and extending along the length of said piston and into said pressure chamber;
• an inlet port in said housing and means placing said inlet port in communication with said inlet passage;
• suction valve means controlling communication of said inlet passage and said inlet passage to allow inflow of fluid only as said piston is retracted;
• an outlet port in said housing;
• outlet passage means in said valve body extending out of said pressure chamber and means placing said outlet passage in communication with said outlet port;
• discharge valve means establishing communication between said outlet passage means and said pressure chamber only as said piston is advanced;
• a first seal interposed between axially facing opposing surfaces on said valve body and said housing, said seal disposed within an inner radial surface of said bushing and surrounding an outer radial surface of said piston;
• a second seal interposed between axially facing opposing surfaces on said bushing and said housing, said second seal disposed within an inner radial surface of said housing and surrounding said outer radial surface of said piston at an axially spaced location from said first seal;
• and
• means for exerting an axial pressure on said valve body and bushing to compress said first and second seals to cause engagement of each seal with said outer radial surface of said piston.

A hydraulic radial-type piston pump including a housing, a cylindrical bushing fit within said housing, a cylindrical valve body, fixed at one end to said bushing body, at least one cylindrical piston performing working strokes and which is slidingly accommodated within said bushing, a pressure chamber defined at one end of said piston;

• a suction and a discharge valve, positioned in line along the longitudinal axis of said piston, said suction and discharge valves opened, and closed respectively by pressure in said pressure chamber, said suction valve having a valve seat at said end of the piston, an inlet port in said housing for receiving the hydraulic fluid to be aspirated and with an outlet port in said housing for receiving the pressurized hydraulic fluid, said pressure chamber being located within said valve body, said discharge valve having a valve seat located at one end of said valve body, a pair of axially spaced annular seals adjacent respective axially facing surfaces of said bushing, one of said surfaces adjacent and facing an opposing, axially facing surface on said valve body, one of said seals interposed between said opposing axially facing surfaces on said bushing and valve body and disposed within an inner radial surface of said bushing, said other axially facing surface on said bushing adjacent an opposing axially facing surface on said housing, the other of said seals interposed between said axially facing surfaces on said bushing and housing and disposed within an inner radial surface on said housing, said seals surrounding the outer radial surface of said piston at axially spaced locations, and means applying an axial force acting to compress said seals between said axially facing surfaces on said bushing and said adjacent portions of said valve body and housing respectively to be forced into sealing engagement with said outer radial surface of said piston.