Expansible chamber devices – Relatively movable working members – Interconnected with common rotatable shaft
Reexamination Certificate
1999-11-10
2002-01-08
Ryznic, John E. (Department: 3745)
Expansible chamber devices
Relatively movable working members
Interconnected with common rotatable shaft
Reexamination Certificate
active
06336392
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a compressor for use in an automobile air conditioner and, in particular, to an improvement of a bearing structure supporting an end of a shaft.
As a typical compressor of the type, there is known a swash-plate compressor having a structure illustrated in FIG.
1
. The swash-plate compressor comprises a front housing
1
, a cylinder block
2
′, and a rear housing (cylinder head)
3
assembled together by the use of a through bolt
4
penetrating through the front housing
1
and the cylinder block
2
′ to be received in the rear housing
3
. Specifically, the front housing
1
is coupled to a front end of the cylinder block
2
′ while the rear housing
3
is coupled to a rear end of the cylinder block
2
′ with a valve plate
9
interposed therebetween. A combination of the front housing
1
and the cylinder block
2
′ defines a crank chamber
15
in which a shaft (drive shaft)
5
′ extends in an axial direction. The shaft
5
′ is rotatably supported by a pair of bearings
18
and
19
attached to the cylinder block
2
′ and the front housing
1
, respectively. Upon assembling, the shaft
5
′ is inserted through the front housing
1
towards the rear housing
3
until one end of the shaft
5
′ is received in a receptacle portion of the cylinder block
2
′. At this time, the one end of the shaft
5
′ is pushed back by an adjusting screw
22
disposed in the cylinder block
2
′ towards the front housing
1
to leave an axial clearance. Thus, the adjusting screw
22
serves to adjust the axial clearance of the shaft
5
′. The cylinder block
2
′ is provided with a plurality of cylinder bores
8
formed at positions surrounding the shaft
5
′ to receive a plurality of pistons
7
inserted therein, respectively.
Within the crank chamber
15
, a swash plate
6
to coupled to the shaft
5
′. Specifically, the shaft
5
′ is inserted into a through hole formed in the swash plate
6
to fix the swash plate
6
around the shaft
5
′. Between the swash plate
6
and the front housing
1
, a thrust bearing
20
having elasticity is interposed to urge the swash plate
6
towards the rear housing
3
. The swash plate
6
has an outer peripheral portion kept in contact with a plurality of semispherical shoes
23
as a coupling mechanism. Each of the shoes
23
has an outer semispherical surface engaged with a ball bearing surface of each of the pistons
7
. Following the rotation of the shaft
5
′, each of the pistons
7
coupled through the shoe
23
to the swash plate
6
performs reciprocal movement within the cylinder bore
8
.
The rear housing
3
has an inner space divided into a suction chamber
10
and a discharge chamber
11
. The valve plate
9
is provided with a suction port
12
and a discharge port
13
formed in an area corresponding to each cylinder bore
8
. A compression space is formed between the valve plate
9
and each of the pistons
7
. Through the suction port
12
and the discharge port
13
, the compression space communicates with the suction chamber
10
and the discharge chamber
11
, respectively. Each suction port
12
is provided with a valve (not shown) for opening and closing the suction port
12
in response to the reciprocal movement of the piston
7
. Likewise, each discharge port
13
is provided with a valve (not shown) for opening and closing the discharge port
13
under the restraint of a retainer
14
in response to the reciprocal movement of the piston
7
.
The swash-plate compressor described above is of a fixed displacement type. When the swash plate
6
is rotated following the rotation of the shaft
5
′, the rotation is transmitted through the shoe
23
to each piston
7
so that each piston
7
performs the reciprocal movement within the cylinder bore
8
. As a consequence, a refrigerant gas is sucked from the suction chamber
10
through the suction port
12
into the compression chamber. The refrigerant gas is compressed within the compression chamber and then discharged through the discharge port
13
to the discharge chamber
11
.
In the swash-plate compressor described above, the adjusting screw for adjusting the axial clearance of the shaft is used. The use of such adjusting screw is disclosed in Japanese Utility Model Publication (JP-Y) No. 3-41101 (41101/1991) which is directed to a variable-displacement compressor.
In the swash-plate compressor described above, the front housing, the cylinder block, and the rear housing are fixed by the use of the through bolt. Alternatively, the front housing and the cylinder block are fixed by a first through bolt while the cylinder block and the rear housing are fixed by a second through bolt. In either event, an assembling process is carried out in the following manner. At first, the shaft, the swash plate, and the piston are coupled to the front housing and the cylinder block. In order to adjust the axial clearance of the shaft, the front housing and the cylinder block are temporarily assembled with the above-mentioned components coupled thereto. An axial end surface at the one end of the shaft is pressed by the adjusting screw to adjust the axial clearance. Thereafter, in order to prevent the adjusting screw from being loosened, an anti-loosening procedure is taken, for example, a head of the adjusting screw is collapsed or caulked. After the other components including the valve plate and the rear housing are coupled, final or permanent assembling is carried out. Thus, the assembling process requires two separate stages including the temporary assembling and the final assembling between which the adjustment of axial clearance and the anti-loosening procedure are carried out. Thus, the assembling process is complicated, time-consuming, and inefficient.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a compressor which is capable of easily adjusting an axial clearance of a shaft and which can be assembled by a simple process with excellent efficiency.
Other objects of the present invention will become clear as the description proceeds.
According to an aspect of the present invention, there is provided a compressor which comprises a cylinder block, a front housing coupled to the cylinder block, a shaft extended in an axial direction and rotatably supported by the cylinder block and the front housing, the shaft being rotated to cause a compressing operation of the compressor, an axial urging arrangement having a compression coil spring for urging the shaft in the axial direction, and a thrust bearing, the axial urging arrangement and the thrust bearing being arranged in series and interposed between an axial end surface of the shaft and the cylinder block.
According to another aspect of the present invention, there is provided a compressor which comprises a cylinder block having a receptacle portion, a shaft extending in an axial direction and having one end inserted into the receptacle portion, a collar fitted over the one end of the shaft, the collar being unrotatable and axially movable with respect to the shaft, and an elastic member arranged inside to elastically urge an axial end surface of the shaft.
According to still another aspect of the present invention, there is provided a compressor which comprises a cylinder block having a plurality of cylinders, a plurality of single-headed pistons adapted to perform reciprocal movement within the cylinders, respectively, a front housing coupled to the cylinder block, a shaft supported by the cylinder block and the front housing, a swash plate integrally fixed to the shaft, a plurality of shoes each of which is interposed between the swash plate and each of the pistons, a pair of radial bearings arranged in the front housing and the cylinder block, respectively, to radially support the shaft, a thrust race bearing arranged between the front housing and the swash plate, a spring for urging an axial end surface of the shaft towards the front housi
Fujita Masaaki
Shimizu Keiji
Baker & Botts L.L.P.
Ryznic John E.
Sanden Corporation
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