| 摘要 |
A self-propelled vehicle, such as a loader, has a hydrostatic drive that includes hydrostatic motors to drive ground engaging wheels under control of the operator. The rotational speed of the motors is proportional to an operator control input provided to a controller which in turn regulates the flow of hydraulic fluid under pressure from a pressure source to the motors. In the form shown, the regulation of the hydraulic fluid under pressure to the motors is achieved by utilizing electrical displacement control pumps that will provide a flow of fluid to a connected motor in direct proportion to an input signal as the flow source. The motors are fixed displacement motors, and when the wheels tend to overrun as the vehicle rolls down a hill or incline, the motors will act as pumps. The movement of the wheels is sensed to provide a signal to the controller to adjust one or both of the electrical displacement control pumps to provide a balancing counter pressure at the high pressure side work port of the associated motor to insure that the vehicle will not creep or roll when it should be stopped. |
