Hydraulic system for battery-powered utility vehicles

A hydraulic system configured to provide a variable flow of hydraulic fluid to a load circuit, the hydraulic system comprising:

• a pump configured to pressurize and output hydraulic fluid;
• an electric motor selectively driving the pump;
• a controller configured to selectively control a target speed of the electric motor based on input from an operator control regardless of a pressure generated by the pump;
• a proportional directional control valve in the load circuit and communicating with the pump and the controller, the proportional directional control valve controlling a flow of hydraulic fluid to a hydraulic actuator associated with the load circuit such that the flow of hydraulic fluid to the hydraulic actuator is proportional to a signal provided by the controller, the signal being a function of the input from the operator control;
• and
• a motor controller communicating with the motor, the motor controller receiving feedback from the motor such that the motor controller is configured to adjust an electric current provided to the motor to maintain the target speed even as load on the motor varies,
• wherein flow of hydraulic fluid to the hydraulic actuator through the proportional directional control valve is varied by the controller making:
• a) variations of the target speed of the motor;
• and
• b) variations of the signal to the proportional directional control valve.

A stand-on loader comprising:

• a frame, the frame supporting
• a platform configured to support an operator of the loader in an open space at a rear end of the stand-on loader;
• a boom configured to raise or lower a load;
• and
• a bucket coupled to the boom for supporting the load;
• a plurality of wheels or tracks coupled to the frame and configured to provide motive movement of the stand-on loader, the plurality of wheels or tracks defining a front rotational axis and a rear rotational axis;
• and
• a hydraulic system configured to provide a variable flow of hydraulic fluid to a boom raise/lower circuit and a bucket tilt circuit, the hydraulic system comprising:
• a pump configured to pressurize and output hydraulic fluid;
• an electric motor selectively driving the pump;
• an operator control including a first control associated with the boom raise/lower circuit and a second control associated with the bucket tilt circuit;
• a controller configured to selectively control a target speed of the electric motor based on a position setting of the operator control;
• a first proportional directional control valve in the boom raise/lower circuit and communicating with the pump and the controller, the first proportional directional control valve controlling a flow of hydraulic fluid to a first hydraulic cylinder associated with the boom such that the flow of hydraulic fluid to the first hydraulic cylinder is proportional to a first signal provided by the controller, the first signal being a function of a position of the first control;
• and
• a second proportional directional control valve in the bucket tilt circuit and communicating with the pump and the controller, the second proportional directional control valve controlling a flow of hydraulic fluid to a second hydraulic cylinder associated with the bucket such that the flow of hydraulic fluid to the second hydraulic cylinder is proportional to a second signal provided by the controller, the second signal being a function of a position of the second control;
• wherein at least a portion of the pump and at least a portion of the electric motor are positioned rearward of the rear rotational axis;
• and
• wherein control of the target speed of the electric motor by the controller is open-loop control in which the target speed of the motor is proportional to the position setting of the operator control regardless of a pressure generated by the pump.