Pump with reciprocating high pressure seal and valve for vehicle braking systems

Abstract

A pump apparatus includes a housing having a bore formed therethrough. A piston is disposed within the bore for reciprocal movement therein. The piston includes a piston body, and an inlet flange extending radially outwardly from the piston body. An outer peripheral surface of the inlet flange and a wall of the bore define a first passageway. A retaining flange extends radially outwardly from the piston body and have a substantially square transverse section. An outer peripheral surface of the retaining flange and the wall of the bore define a second passageway. An intermediate portion is disposed between the inlet flange and the retaining flange. An annular seal is disposed around the intermediate portion of the piston body. The seal slidingly engages the wall of the bore, and the seal and the piston cooperate to form a check valve assembly.

1 . A pump apparatus comprising: 
 a housing having a bore formed therethrough;    a piston disposed within said bore for reciprocal movement therein, said piston comprising: 
 a piston body;  
 an inlet flange extending radially outwardly from said piston body, an outer peripheral surface of said inlet flange and a wall of said bore defining a first passageway;  
 a retaining flange extending radially outwardly from said piston body and having a substantially square transverse section, an outer peripheral surface of said retaining flange and said wall of said bore defining a second passageway; and  
 an intermediate portion disposed between said inlet flange and said retaining flange;  
   an annular seal disposed around said intermediate portion of said piston body, said seal slidingly engaging said wall of said bore, said seal and said piston cooperating to form a check valve assembly.    
   
   
       2 . The pump apparatus of  claim 1 , wherein said bore of said housing is divided into an inlet chamber and a pumping chamber by said check valve assembly, said seal being moveable to a first position spaced apart from said inlet flange such that said check valve assembly is in a flow-through position to allow fluid to fill the pumping chamber, such that fluid flows between said seal and said intermediate portion of said piston, said seal being further moveable to a second position sealing against said inlet flange such that said check valve assembly is in a closed position to allow fluid within said pumping chamber to be pressurized during movement of said piston in a pumping stroke.  
   
   
       3 . The pump apparatus of  claim 1 , wherein an outer peripheral surface of said intermediate portion is substantially cylindrical.  
   
   
       4 . The pump apparatus of  claim 1 , wherein an outer peripheral surface of said inlet flange is substantially cylindrical.  
   
   
       5 . The pump apparatus of  claim 2 , wherein said piston body includes: 
 a first end extending into said pumping chamber;    a second end extending into said inlet chamber;    a first body portion between said first end and said retaining flange, an outer circumferential surface of said first body portion including a flat portion extending axially from said retaining flange toward said first end of said piston body, said flat portion being substantially coplanar with a peripheral side surface of said retaining flange; and    a second body portion between said second end and said inlet flange.    
   
   
       6 . The pump apparatus of  claim 5 , wherein said first body portion includes four radially arrayed flat portions extending axially from said retaining flange toward said first end of said piston body, each of said flat portions being substantially coplanar with a peripheral side surface of said retaining flange.  
   
   
       7 . The pump apparatus of  claim 5 , wherein said flat portion and said wall of said bore define a portion of said second passageway.  
   
   
       8 . The pump apparatus of  claim 5 , wherein said second body portion includes a reduced diameter portion.  
   
   
       9 . A check valve assembly for a vehicle braking system pump comprising: 
 a piston including: 
 a piston body;  
 an inlet flange extending radially outwardly from said piston body;  
 a retaining flange extending radially outwardly from said piston body and having a substantially square transverse section; and  
 an intermediate portion disposed between said inlet flange and said retaining flange; and  
   an annular seal disposed around said intermediate portion of said piston, said seal and said piston cooperating to form a check valve assembly, said seal being moveable to a first position spaced apart from said inlet flange such that said check valve assembly is in a flow-through position, wherein a passageway is defined between said seal and said intermediate portion of said piston, said seal being moveable to a second position sealing against said inlet flange in which said check valve assembly is in a closed position.    
   
   
       10 . The check valve assembly of  claim 9 , wherein an outer peripheral surface of said intermediate portion is substantially cylindrical.  
   
   
       11 . The check valve assembly of  claim 9 , wherein an outer peripheral surface of said inlet flange is substantially cylindrical.  
   
   
       12 . The check valve assembly of  claim 9 , wherein said piston body further includes: 
 a first end;    a second end;    a first body portion between said first end and said retaining flange, an outer circumferential surface of said first body portion including a flat portion extending axially from said retaining flange toward said first end of said piston body, said flat portion being substantially coplanar with a portion of a peripheral side surface of said retaining flange; and    a second body portion between said second end and said inlet flange.    
   
   
       13 . The check valve assembly of  claim 12 , wherein said first body portion includes a plurality of radially arrayed flat portions extending axially from said retaining flange toward said first end of said piston body, each of said flat portions being substantially coplanar with a portion of a peripheral side surface of said retaining flange.  
   
   
       14 . The check valve assembly of  claim 12 , wherein said flat portion defines a fluid flow path.  
   
   
       15 . The check valve assembly of  claim 12 , wherein said second body portion a includes a reduced diameter portion.  
   
   
       16 . A piston and seal assembly for a vehicle braking system pump comprising: 
 a piston having a first end, a second end, an inlet flange, a retaining flange, and an intermediate portion disposed between said inlet flange and said retaining flange, a first piston portion being defined between said retaining flange and said first end of said piston, and a second piston portion being defined between said inlet flange and said second end of said piston; and    an annular seal disposed around said intermediate portion of said piston, said seal and said piston cooperating to form a first check valve assembly, said seal being moveable to a first position relative to said inlet flange in which said first check valve assembly is in a flow-through position, wherein a passageway is defined between said seal and said intermediate portion of said piston, said seal being moveable to a second position relative to said inlet flange in which said first check valve assembly is in a closed position;    wherein an outer circumferential surface of said first piston portion includes at least one flat portion extending axially from said retaining flange toward said first end of said piston, said at least one flat portion defining a plane parallel with an axis of said piston.    
   
   
       17 . The piston and seal assembly of  claim 16 , wherein said first piston portion has the shape of the frustum of a cone, a peripheral edge of said at least one flat portion defining a hyperbola.  
   
   
       18 . The piston and seal assembly of  claim 16 , wherein said first piston portion includes a first part and a second part, said first part having the shape of the frustum of a cone, said second part having the shape of a cylinder and being between said retaining flange and said first part, and wherein said at least one flat portion includes a first planar area in said first part coplanar with a second planar area in said second part, said first planar area having a peripheral edge defining a hyperbola, said second planar area having a peripheral edge defining a rectangle.  
   
   
       19 . The piston and seal assembly of  claim 18 , wherein said at least one flat portion further includes a third planar area in said intermediate portion and coplanar with said first and second planar areas, said third planar area having a peripheral edge defining a rectangle.