In a refrigerant compressor wherein a piston slidably received in a cylinder bore is operable on refrigerant gas for compression and the compressed gas is discharged through an outlet port while pushing, or springing out a flexible reed valve normally closed over the port, the pressure built up in the cylinder bore during gas discharging depends on resistance against the flow of gas through the outlet port. To establish the discharged gas pressure at a desired value, a retainer is usually provided in the compressor for restricting the maximum opening of the discharge reed valve. In operation, the discharge reed valve is opened when the gas pressure in the cylinder bore is increased above a predetermined value and the reed valve opening movement is stopped by the retainer.
A valve retainer for restricting the opening of a discharge reed valve is disclosed, for example, in the Publication of Unexamined Japanese Patent Application 60-209674 (1985). This retainer is formed as an integral part of a circular gasket plate mounted between an end housing of the compressor and a valve plate. The retainer portion of the gasket plate is formed as a slightly raised portion with a slant extending from its base portion lying in the plane of the gasket plate toward its radially outward distal end so as to conform to the "sprung-out" shape of the discharge reed valve when fully opened. The gasket plate is formed also with a slit-shaped aperture adjacently to the distal end of the retainer portion, providing a relatively large space or passage for allowing compressed gas to flow therethrough toward a discharge chamber. The retainer portion is held in its raised position by a pair of lateral support or stay portions formed as an integral part of the gasket plate on opposite sides of the distal end portion of the retainer, so that a clearance is formed on each side of the base portion of the retainer through which part of the compressed refrigerant gas may escape. It is noted, however, that most of the compressed gas comes out of the cylinder bore through the slit-shaped aperture adjacent to the distal end of the retainer.
The gasket plate, in which the retainer is formed integrally therewith, is made as thin as possible for the sake of lightweightness of the compressor and, therefore, the retainer is held in position by the above paired stay portions having a relatively thin structure. That is, high pressure of the compressed refrigerant gas received by the retainer is transmitted inevitably to the stay portions. Application of such high pressure causes harmful stresses in the retainer, particularly at outer edges of the stay portions, with the result that damage or breakage may occur at such locations of the retainer.