Variable displacement pump

A variable displacement pump, comprising:

• a pump housing including a pump element accommodation part thereinside;
• a cam ring formed in an annular shape and provided inside the pump element accommodation part;
• a pump element rotatably provided inside the cam ring and configured to carry out suction and discharge of hydraulic fluid;
• a first fluid pressure chamber and a second fluid pressure chamber that are a pair of spaces provided between the pump element accommodation part and the cam ring, wherein by acting a pressure of at least the first fluid pressure chamber on the cam ring, the cam ring is driven, and a proper discharge amount that is a discharge amount per one rotation of the pump element varies;
• a suction port provided to the pump housing and opened to a suction region of the pump element;
• a discharge port provided to the pump housing and opened to a discharge region of the pump element;
• a suction passage provided to the pump housing and used for supplying the hydraulic fluid to the suction port;
• a discharge passage provided to the pump housing and used for supplying the hydraulic fluid discharged from the discharge port to an outside of the pump housing;
• a variable metering orifice that is a throttle portion provided to the discharge passage;
• a first control valve that is a first control valve controlled based on a pressure on an upstream side and a pressure on a downstream side of the variable metering orifice, and which is configured to control a pressure to be introduced into the first fluid pressure chamber with the pressure on the upstream side of the metering orifice and a pressure of the suction passage;
• and
• a second control valve that is a second control valve configured to variably control an opening area of the variable metering orifice, and which is provided with a valve body controlled based on a pressure of the second fluid pressure chamber or the suction passage and a pressure of the first fluid pressure chamber.