Patent ID: 6109896
Filing Date: 2000-08-29
Classification: B60T,F04B,F05C,Y10T

Abstract:
A piston pump for pumping hydraulic fluid for vehicle brake systems, comprising a stepped piston axially displaceable in a pump space (11), said piston includes one piston portion which divides the pump space into a low-pressure chamber (21) and a high-pressure chamber (22) of variable chamber volume, the stepped piston (12) includes a cylinder portion (14) which forms a larger diameter cylinder portion (142), and a smaller diameter cylinder portion (141) having a shoulder (15) oriented toward the high-pressure chamber (22) at a transition between said larger-diameter cylinder portion (142) and said smaller diameter cylinder portion (141), and a bush (16, 16') holds an elastomer seal (17) that seals the high-pressure chamber (22) off from the low-pressure chamber (21).