Investigation on a novel high frequency two-dimensional (2D) rotary valve variable mechanism for fluid pulse-width-modulation application

In the traditional valve controlled hydraulic system, flow control is realized by changing the orifice area of the control valve, which inevitably leads to throttling loss. However, the high-speed on-off valve is different from other control valves because it realizes the instantaneous release of energy by quickly opening the valve port. Therefore, it can be theoretically considered that there is no throttling loss in the fully open state. Inspired by the operating principle of the high-speed on/off valve, a novel high frequency two-dimensional (2D) rotary valve variable mechanism is proposed, which is used to generate discrete fluid by the fluid pulse-width-modulation to control and distribute the flow. This rotary valve variable mechanism is similar to an on/off valve group, and a group of rhombic valve ports are evenly arranged on the circumferential shoulder. The valve spool has two non-interference degrees of freedom: rotary motion and sliding. With the high speed rotation of the valve spool, the valve port can be quickly ‘opened’ (connected with the load) - ‘closed’ (connected with the oil tank); while the valve spool slides, the duration ratio of "on" and "off" of the valve port can be adjusted. Similar to the on-off valve, the flow through the rotary valve port mainly depends on the communication time of the valve port (the instant of opening and closing the valve port is not in the scope of discussion). The concept of 2D rotary valve variable mechanism is verified by the simulation and the experiment. The results show that the variable mechanism generates discrete fluid with adjustable duty cycle. In the PWM driven high-speed on/off valve, this is the technology to realize the fluid pulse-width-modulation through the mechanical structure of the fluid control element itself, rather than the PWM control to control the motor, and finally the fluid is controlled to meet the system's demand for oil supply.