| 摘要 |
A hydraulic brake system comprises a pedal-actuated tandem generator cylinder (3), an auxiliary-pressure supply system with electromotively driven pump (8) and pressure fluid supply reservoir (31) and an auxiliary-pressure control valve (7, 67). The tandem generator cylinder (3) is provided with a bore (24) extending wherethrough is an actuating rod (25, 72) which acts upon a primary piston (4, 68) and whose end remote from the primary piston (4, 68) cooperates with an initial-pressure piston (16) or a vacuum brake power booster (84) slidably supported in the bore (24) and being in turn coupled with the brake pedal (19) by way of a piston rod (17, 86). An annular piston (26) is displaceably arranged in the bore (24) between the primary piston (4, 68) and the initial-pressure piston (16) or, respectively, the force-output member (74) of the booster (84). The annular piston subdivides the space between the primary piston (4, 68) and the initial-pressure piston (16 ) or the force-output member (74) into two chambers (59 and 44), the one thereof communicating with a feed tank (6) of the tandem generator cylinder (3), while the other one is connected to the pressure-fluid supply reservoir (31). The working chamber (44) accommodates an annular disc (29) comprising a ramp (30) which coacts with the contact pin (32) of an electric switch (33) which switches on the pump (8) when the initial-pressure piston (16) or the force-output member (74) has displaced the annular disc (29) in the actuating direction. An auxiliary cylinder (62), or the working chambers of the vacuum brake power booster (84) whereon the brake pedal (19) is acting, is connected to the auxiliary-pressure control valve (7, 67). The pressure in the auxiliary cylinder (62) or the pressure in the working chambers of the booster (84) controls the pressure of the pump (8) which communicates with the feed tank (6).
|
