Vehicle IC engine driven pump - is operated by leverage with movable pivot for varying output inversely to pressure

摘要

The hydraulic vehicle brake system pump (9) is actuated by an engine-driven cam (3) acting on one end of a two-armed lever (6) whose other end bears against the spring-loaded (4) pump plunger (8). This lever has a movable pivot (29) mounted on the cylinder (23) of a piston (24) cylinder unit parallel to the lever. A drill through piston bore (25) is connected to pump discharge so that pump pressure can move the cylinder against a spring (27). When that pressure reaches working level this locates the pivot so that plunger travel does not involve the effective part (14) of the cylinder. Thus the delivery quantity of the pump is automatically controlled within a range from zero to max. in dependence on delivery pressure.