1. Field of the Invention
This invention relates to a refrigerant compressor, and more particularly to a refrigerant compressor for use in an air conditioning system for an automotive vehicle.
2. Description of the Prior Art
Conventionally, a refrigerant compressor, such as a swash plate compressor, includes a cylinder block formed therethrough with a plurality of cylinder bores, a housing secured to the cylinder block, a swash plate which is tiltably mounted on a drive shaft, for rotation in unison with the drive shaft, a plurality of pistons each reciprocating within a corresponding one of the cylinder bores as the swash plate rotates, and a crankcase defined in the housing. The swash plate is received in the crankcase.
When the compressor is in operation, lubricant collected at a bottom of the crankcase is drawn up and splashed within the crankcase by rotating members including the swash plate as they rotate to be supplied to sliding portions of bearings, the pistons, and other components within the crankcase (so-called splash lubrication method).
Another lubricating method of supplying lubricant is a forced-feed lubrication method in which lubricant is forcedly fed to a particular sliding portion by the use of a pump, such as a trochoid pump driven by torque transmitted from a drive shaft of a compressor.
However, when the splash lubrication method is employed, a sufficient amount of lubricant cannot be supplied to unexposed sliding members within the crankcase, such as bearings supporting a rear end of the drive shaft.
On the other hand, the forced-feed lubrication method makes it possible to supply a sufficient amount of lubricant even to the unexposed sliding portions within the crankcase. However, this method necessitates provision of a pump, which results in increased manufacturing costs of the compressor. Moreover, it is necessary to secure space for installation of the pump, which inevitably increases the size and weight of the compressor.