| 摘要 |
<p>A hydraulic drive system (2) for a vehicle includes a pressurizing circuit (5, 5'') and a working circuit (7, 7', 7'', 7...). The pressurizing circuit incorporates a pump (11) driven by a prime mover (20) having a nominal horsepower rating. The prime mover is either shut off or idled when the pressure sensed within the pressurizing circuit is within a desired range and run at an optimum high RPM range when the pressure falls below the desired range. At least one accumulator (29) is provided in the pressurizing circuit. The working circuit includes a plurality of motors (107, 108, 128, 129; 606-609; 651-654; 687a-692b) for driving at least one vehicle wheel and a motor control valve arrangement (97, 133, 134; 621-624; 666-669; 710-716) which isolates one or more motors from the flow of pressurized fluid while deactivated and drives the motors while activated. As vehicle speed increases and drive resistance decreases, the number of motors propelling the vehicle is progressively reduced. A flow control valve alters fluid flow to the motors.</p> |
