Abstract: A zero turn mower vehicle 10 includes left and right hydrostatic transmissions 11a, 11b driving wheels 15a, 15b. The transmissions 11a, 11b each include a swashplate type axial piston hydraulic pump 17 having a swashplate 22. A system 12 and method controls each pump 17. A controller 31 receives input signals and provides output signals to electric motors 33a, 33b to control each swashplate 22. Operator interface input devices 30a, 30b provide inputs to controller 31. Angle sensors 35a, 35b provide additional inputs to controller 31. Displacement amplifiers 36a, 36b amplify displacement of each swashplate 22, and torque amplifiers 34a, 34b amplify torque of electric motors 33a, 33b.

Abstract: Provided is a hydrostatic transmission including a pump/motor module having a reservoir housing and a hydraulic pump and motor disposed in the reservoir housing, and a speed reduction module having a speed reduction housing coupled to the reservoir housing and a speed reduction assembly disposed in the speed reduction housing. The speed reduction assembly includes an input member driven by the output shaft of the hydraulic motor, an output member rotationally connected to the input member by one or more belts/chains, and an axle shaft driven by rotation of the output member. By providing the speed reduction assembly in a separate housing from the hydraulic fluid in the reservoir housing, the speed reduction assembly is isolated from the hydraulic fluid thereby preventing particulates from the speed reduction assembly from entering the hydraulic fluid in the reservoir housing.

Abstract: A hydraulic apparatus is provided with a return to neutral mechanism for returning a trunnion control bracket arm to a neutral position. The return to neutral mechanism comprises a pair of springs, one spring connecting a fixed bracket to a first rotatable bracket and the other spring connecting the fixed bracket to a second rotatable bracket. The mechanism uses springs with different spring constants and the springs are attached to the brackets in a single plane.

Abstract: A zero turn mower vehicle 10 includes left and right hydrostatic transmissions 11a, 11b driving wheels 15a, 15b. The transmissions 11a, 11b each include a swashplate type axial piston hydraulic pump 17 having a swashplate 22. A system 12 and method controls each pump 17. A controller 31 receives input signals and provides output signals to electric motors 33a, 33b to control each swashplate 22. Operator interface input devices 30a, 30b provide inputs to controller 31. Angle sensors 35a, 35b provide additional inputs to controller 31. Displacement amplifiers 36a, 36b amplify displacement of each swashplate 22, and torque amplifiers 34a, 34b amplify torque of electric motors 33a, 33b.

Abstract: Provided is a hydrostatic transmission including a pump/motor module having a reservoir housing and a hydraulic pump and motor disposed in the reservoir housing, and a speed reduction module having a speed reduction housing coupled to the reservoir housing and a speed reduction assembly disposed in the speed reduction housing. The speed reduction assembly includes an input member driven by the output shaft of the hydraulic motor, an output member rotationally connected to the input member by one or more belts/chains, and an axle shaft driven by rotation of the output member. By providing the speed reduction assembly in a separate housing from the hydraulic fluid in the reservoir housing, the speed reduction assembly is isolated from the hydraulic fluid thereby preventing particulates from the speed reduction assembly from entering the hydraulic fluid in the reservoir housing.

Abstract: A hydraulic apparatus is provided with a return to neutral mechanism for returning a trunnion control bracket arm to a neutral position. The return to neutral mechanism comprises a pair of springs, one spring connecting a fixed bracket to a first rotatable bracket and the other spring connecting the fixed bracket to a second rotatable bracket. The mechanism uses springs with different spring constants and the springs are attached to the brackets in a single plane.