| 摘要 |
A combined master cylinder and dump valve includes a piston slideable within a body bore that defines a master cylinder for pressurizing a brake port. The piston includes a piston seal for isolating a pressure port from a tank port, a piston bore, a first piston hole set for hydraulically connecting the pressure port to the piston bore and a second piston hole set for hydraulically connecting the piston bore to the tank port. A plunger slideably received in the piston bore has a plunger hole set for selectively connecting the first piston hole set with a plunger bore, and a plunger seal arrangement for selectively isolating the first piston hole set from the plunger bore. The plunger bore is hydraulically connected to the piston bore. In a rest condition, the master cylinder is unpressurized and the plunger seal arrangement isolates the first piston hole set from the plunger bore, thereby isolating the pressure port from the tank port. In an actuated condition, the plunger acts to slideably move the piston to pressurize the brake port. The plunger hole set hydraulically connects the first piston hole set with the plunger bore, hydraulically connecting the pressure port to the tank port.
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