Swash-plate type compressor

#The present invention relates to a swash-plate type compressor for use in air conditioners for vehicles or the like, and more particularly to lubrication of the bearing portions supporting the drive shaft as well as the sliding portions between the swash plate and the pistons.

#As known, e.g., from U.S. Pat. No. 3,801,227, a conventional compressor of this kind is typically constructed such that a pair of cylinder blocks are combined together in axial alignment and horizontally disposed. The cylinder blocks each include an axial through bore extending along the axis thereof, through which bore a drive shaft extends. A swash plate is secured on the drive shaft. Each one pair of valve plates and cylinder heads are mounted on the outer ends of the combined cylinder blocks. The cylinder blocks further include a plurality of cylinder bores axially extending therethrough, in each of which a piston is slidably received. The cylinder bore, the piston and the valve plate deline in cooperation a pumping chamber therebetween. The swash plate has its outer fringe disposed in engagement with the pistons in such a manner that rotation of the drive shaft causes the pistons to make reciprocating motions within the cylinder bores by means of the swash plate, for pumping action. The drive shaft is supported in the radial directions by radial bearings mounted within the through bores and in the axial directions by thrust bearings arranged at opposite sides of the swash plate.

#With this arrangement, lubrication of the radial bearings, the thrust bearings and the sliding portions between the swash plate and the pistons is carried out due to a pressure differential produced in the compressor. More specifically, an oil reservoir is provided beneath the swash plate chamber between the cylinder blocks. Lubricating oil stored in the oil reservoir is splashed into a mist by the swash plate being rotated in unison with rotation of the drive shaft, and the misty oil is supplied to the thrust bearings arranged at the opposite sides of the swash plate and the sliding portions between the swash plate and the pistons. Simultaneously, due to a pressure differential between the swash plate chamber and the radial bearing sections which is caused by the reciprocating motions of the pistons within the cylinder bore which are in communication with the swash plate chamber, part of the misty oil fed to the thrust bearings is delivered to the radial bearings through gaps between the drive shaft and the axial through bores.

#FIG. 1 is a longitudinal sectional view of a conventional swash-plate type compressor;

#FIG. 2 is a longitudinal sectional view of a swash-plate type compressor according to one embodiment of the invention; and

#FIG. 3 is a sectional view taken along line A--A in FIG. 2, showing only a cylinder block used in the compressor; and

#Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout the views, FIG. 1 illustrates a conventional swash-plate type compressor. A pair of cylinder blocks 1, 2 are combined together in axial alignment with their axes horizontally disposed. These combined cylinder blocks 1, 2 are formed therein with a plurality of cylinder bores 3, 4 extending along the axes of the cylinder blocks and a plurality of through bores interposed between adjacent cylinder bores 3, 4 (each one of the cylinder bores and the through bores 5, 6 is shown in FIG. 1). Secured to the outer ends of the combined cylinder blocks 7, 8 are cylinder heads 7, 8 with valve plates 9, 10 intervenining between the cylinder blocks 1, 2 and the cylinder heads 7, 8. The cylinder heads, the cylinder blocks and the valve plates are connected together in an airtight manner.

#A drive shaft 11 extends through the cylinder blocks 1, 2 axially thereof, on which a swash plate 12 is rigidly fitted. The drive shaft 11 further extends outwardly of the compressor through the front cylinder head 7 via a sealing member 21 fitted in the same head. The cylinder blocks 1, 2 have boss portions 13, 14 formed therein with through bores 15, 16 in which the drive shaft 11 is inserted. Radial bearings 17, 18 which are formed of plain bearings, are arranged within the through bores 15, 16 for supporting the drive shaft 11 in the radial directions, while thrust bearings 19, 20, which are formed of needle bearings, are mounted between the boss portions 13, 14 and the swash plate 12 at opposite ends of the latter, for supporting the swash plate 12 in the axial directions.

#The swash plate 12 has its outer fringe disposed in engagement with double acting pistons 24 via shoes 22 and balls 23, which pistons are slidably received within the cylinder bores 3, 4 of the opposed cylinder blocks 1, 2.