To provide a check valve which hardly causes a hunting phenomenon after valve opening, thus reducing abnormal noises, vibrations and pressure losses in a compressor, a cooling circuit and a vehicle.
This check valve 33 is composed of a valve seat member 70, a housing 71, a valve element and a spring. In this case, a communicating port 71b of the case 71 has no linear portion extending from a seat face in the other direction, is symmetric with respect to the axial direction and is shaped into an isosceles triangle whose vertical angle faces the seat face. Accordingly, the opening area of the communicating port 71b is below proportional relation with respect to lift length of the valve element heading in the other direction from the seat face.
IMANISHI TAKESHI
KIMURA KAZUYA
MORISHITA ATSUSHI
