초록 ▼

A transmission assembly includes a variable displacement hydraulic pump, a hydraulic motor operatively connected to the pump, a speed sensor operable to sense the speed of an output shaft of the motor, a first actuator for setting displacement of the pump in a positive displacement range in response

A transmission assembly includes a variable displacement hydraulic pump, a hydraulic motor operatively connected to the pump, a speed sensor operable to sense the speed of an output shaft of the motor, a first actuator for setting displacement of the pump in a positive displacement range in response to a first actuator command and a second actuator for setting displacement of the pump in a negative displacement range in response to a second actuator command. A controller is operable to transmit first actuator commands to the first actuator and transmit second actuator commands to the second actuator in response to operator inputs. The operator inputs require that the displacement of the pump to move from the positive displacement range to the negative displacement range. The controller generates first actuator commands which cause the first actuator to set the displacement to zero. The controller generates second actuator commands in response to the speed of the output shaft reaching a predetermined motor speed limit which cause the second actuator to set the displacement of the pump in the negative displacement region.

대표청구항 ▼

1. A method of controlling a transmission having (i) a variable displacement hydraulic pump, (ii) a hydraulic motor operatively connected to the pump, (iii) a speed sensor operable to sense a speed of an output shaft of the hydraulic motor, (iv) a first actuator for setting displacement of the pump

1. A method of controlling a transmission having (i) a variable displacement hydraulic pump, (ii) a hydraulic motor operatively connected to the pump, (iii) a speed sensor operable to sense a speed of an output shaft of the hydraulic motor, (iv) a first actuator for setting displacement of the pump in a positive displacement range in response to a first actuator command, (v) a second actuator for setting displacement of the pump in a negative displacement range in response to a second actuator command, and (vi) a controller operable to transmit first actuator commands to the first actuator and transmit second actuator commands to the second actuator in response to operator inputs, comprising the steps of:receiving operator inputs which require the displacement of the pump to move from the positive displacement range to the negative displacement range; generating first actuator commands which cause the first actuator to set the displacement to zero; and generating second actuator commands in response to the motor speed reaching a predetermined motor speed limit which cause the second actuator to set the displacement of the pump in the negative displacement region, the second actuator commands coinciding with a transitioning drive condition of the transmission between first and second transmission operating ranges.