Automatic transmission pump apparatus or pump apparatus

An automatic transmission pump apparatus for supplying hydraulic fluid to an automatic transmission of a vehicle, the automatic transmission pump apparatus comprising:

• a pump housing including a pump element containing portion;
• a driving shaft pivotally supported on the pump housing;
• a pump element provided in the pump element containing portion and configured to be rotationally driven by the driving shaft, the pump element forming a plurality of pump chambers around the driving shaft;
• an intake port formed at the pump housing and opened to an intake region where a volume of a pump chamber increases according to a rotation of the driving shaft among the plurality of pump chambers;
• a discharge port formed at the pump housing and opened to a discharge region where the volume of the pump chamber reduces according to the rotation of the driving shaft among the plurality of pump chambers;
• a discharge passage connected to the discharge port;
• and
• a venturi portion provided on the way along the discharge passage, the venturi portion including a small diameter portion having a smaller inner diameter than an inner diameter of the discharge passage from the discharge port to the venturi portion and an inner diameter gradually-increasing portion formed in such a manner that an inner diameter thereof gradually increases from the small diameter portion toward a downstream side of the discharge passage;
• and
• a control valve configured to receive introduction of hydraulic fluid on an upstream side of the venturi portion and hydraulic fluid in the venturi portion, the control valve including a spool valve body controlled based on a differential pressure between the hydraulic fluid on the upstream side of the venturi portion and the hydraulic fluid in the venturi portion, the control valve being configured to control a flow amount of the hydraulic fluid to be supplied into the automatic transmission at least by switching a flow passage of the hydraulic fluid introduced from the upstream side of the venturi portion.