| 摘要 |
1,223,212. Hydraulic reciprocating-pumps. BENDIX CORP. April 8, 1969 [April 22, 1968], No.17906/68. Heading F1A. [Also in Division F2] In a pump for a braking system a pumping plunger 24 mating with a fixed block 28 is driven by an eccentric 20 and a valve member 42 controls a port 34 between a port 32 and an inlet chamber 14, the valve member being actuated by a plunger 54 to which the pressure at an outlet port 40 is applied through passages 60, 62, a chamber 58 and a helical passage between screw threads for a plug 48. Pressure fluctuations at the chamber 58 are reduced by the helical passage. A compression spring 44 opposes the downward thrust on the plunger 54. Harmonic motion at the centre of the spring owing to said pressure fluctuations and/or external vibrations is damped by friction due to a sleeve 68. Alternatively, or additionally, the spring is coated with an elastomeric material and/or a portion 72 of one central coil lies in a plane 73 normal to the axis 74. A non-return valve 38 co-operates with the block 28. |
