| 摘要 |
Single and dual brake feel augmentation valves for use in a vehicle skid control system are disclosed. The brake feel augmentation valve has a first port which receives hydraulic fluid from a constant source, a second port which receives hydraulic fluid from a pilot operated pressure metering valve, a third port which supplies hydraulic fluid to the brakes, and a hydraulic return port. A pressure balancing spool valve, with a brake pressure feedback channel, controls the supply of hydraulic fluid to the brake pressure port from the constant source port as a function of the metered pressure and fedback brake pressure. When the metered pressure is greater than the fedback brake pressure, the spool valve allows hydraulic fluid from the constant source to flow into the brake pressure port, thereby filling the brakes. The spool valve blocks the flow of hydraulic fluid to the brake pressure port from the constant supply port when the fedback brake pressure acting on the spool valve is equal to or greater than the metered pressure. Since the brakes are filled by a constant source of hydraulic fluid, rather than by the pilot's metering valve, the pressure drop which occurs while the brakes fill is isolated from the pilot's pressure metering valve and brake pedal. The brake pedal, therefore, has a more responsive feel during the brake filling process.
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