Throttling overflow valve

The invention discloses a throttling overflow valve. The throttling overflow valve is composed of a valve body, a spring, a valve deck and a valve element. The throttling overflow valve is characterized in that a cylindrical cavity is formed in the valve body; the rear end of the valve body is open; an oil inlet is formed in the front end of the valve body; an oil overflow port is formed in the front side of the valve body; the rear end of the valve body is buckled to the valve deck; the valve element is arranged in the cavity; the spring is located behind the valve element; a throttling hole is formed in the front end of the valve element; an overflow hole is formed in the front side of the valve element; and when the front end of the valve element abuts against the front end of the valve body, the overflow hole of the valve element is communicated with the overflow port of the valve body, and the throttling hole is communicated with the overflow hole. The throttling overflow valve is of a single structure, is simple in structure, small in size and sensitive in response, solves low-speed (the rotation speed is smaller than 100r/min) running problem, and meanwhile has an overload protection function for a system. Compared with a common safety valve, the throttling overflow valve has the beneficial effects that a small-amplitude pressure fluctuation response is fast, meanwhile, the pressure overload protection function is achieved, and pressure over speed is small in the overflow process.