Expansible chamber devices – Relatively movable working members – Interconnected with common rotatable shaft
Reexamination Certificate
1999-10-13
2001-04-10
Ryznic, John E. (Department: 3745)
Expansible chamber devices
Relatively movable working members
Interconnected with common rotatable shaft
C092S169100
Reexamination Certificate
active
06212995
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a variable-displacement inclined plate compressor, and, more specifically, to a variable-displacement inclined plate compressor with an improved structure of cylinder bores of a cylinder block suitable, for use in a refrigerating cycle of an air conditioner for vehicles.
2. Description of Related Art
Variable-displacement inclined plate compressors are known in the art. A known structure of a variable-displacement inclined plate compressor is constructed as depicted in
FIG. 4
, and such a compressor structure is disclosed, for example, in JP-A-7-91366. In
FIG. 4
, front housing
2
is connected to the front side of cylinder block
1
, and rear housing
3
is connected to the rear side of cylinder block
1
via valve plate
4
. A crank chamber
5
is defined by cylinder block
1
and front housing
2
. A drive shaft
6
, extending in its axial direction X, is disposed in crank chamber
5
. Drive shaft
6
is rotatably supported by bearings
7
a
and
7
b
. Cylinder bores
8
are defined in cylinder block
1
around a central bore
41
, into which one end of drive shaft
6
is inserted. Pistons
9
are slidably inserted into the respective cylinder bores
8
.
Rotor
10
is fixed onto drive shaft
6
in crank chamber
5
. Rotor
10
rotates synchronously with the rotation of drive shaft
6
. Rotor
10
is rotatably supported by bearing
7
c
relative to front housing
2
. Inclined plate
11
is provided around drive shaft
6
at a rear side of rotor
10
in crank chamber
5
. Drive shaft
6
is inserted into a through hole
20
defined at the center of inclined plate
11
. Supporting portion
20
a
is formed in through hole
20
. Inclined plate
11
is supported on drive shaft
6
via supporting portion
20
a
, so that inclined plate
11
may be slid along axial direction X of drive shaft
6
and rotated synchronously with the rotation of drive shaft
6
. Spring
12
is interposed between rotor
10
and inclined plate
11
. Spring
12
urges inclined plate
11
in the direction toward rear housing
3
.
Semi-spherical shoe
14
is provided between the radially outer portion of inclined plate
11
and each piston
9
. Shoe
14
connects inclined plate
11
and each piston
9
by the slidable engagement of shoe
14
with the side surfaces of inclined plate
11
and the spherical inner surface of each piston
9
. Thus, respective pistons
9
, slidably engaged with inclined plate
11
via respective shoes
14
, may be reciprocally moved in respective cylinder bores
8
. Hinge mechanism K is provided on the front side of inclined plate
11
. Hinge mechanism K has a pair of brackets
15
positioned at both sides of top dead center position T of inclined plate
11
. A first end of guide pin
16
is fixed to each bracket
15
, and a second end of guide pin
16
is formed as a spherical portion
16
a.
A pair of supporting arms
17
are provided on rotor
10
, so that each supporting arm
17
slidably engages corresponding guide pin
16
. These supporting arms
17
form the remaining part of hinge mechanism K. Guide hole
17
a
is defined on the tip portion of each supporting arm
17
. Guide hole
17
a
extends in parallel to a plane defined by axis X of drive shaft
6
and top dead center position T of inclined plate
11
, and extends straight in a direction approaching from radially outside of axis X of drive shaft
6
. The axial directions of respective guide holes
17
a
are set, so that top dead center position T of piston
9
does not vary significantly in the front/rear direction despite the inclination of inclined plate
11
. Respective spherical portions
16
a
of respective guide pins
16
are inserted rotatably and slidably into respective guide holes
17
a.
When spring
12
is at its maximum extension, rear end recess
11
b
of inclined plate
11
, which is formed at the rear end of through hole
20
, comes into contact with C-clip
13
engaged on drive shaft
6
. By this contact, inclined plate
11
is restricted from further movement in an inclination angle decreasing direction. When spring
12
is fully contracted, front end surface
11
a
of inclined plate
11
, which is formed at the lower front side surface of inclined plate
11
as an inclined surface, comes into contact with rear end surface
10
a
of rotor
10
. By this contact, inclined plate
11
is restricted from further movement in an inclination angle increasing direction.
The interior of rear housing
3
is divided into suction chamber
30
and discharge chamber
31
. Suction port
32
and discharge port
33
are opened on valve plate
4
in correspondence with each cylinder bore
8
. A compression chamber, formed between valve plate
4
and piston
9
, may communicate with suction chamber
30
and discharge chamber
31
via suction port
32
and discharge port
33
. A control valve (not shown) is provided on each suction port
32
to control the opening and closing of suction port
32
. A control valve (not shown) is provided also on each discharge port
33
to control the opening and closing of discharge port
33
. The opening operation of the control valve for discharge port
33
is restricted by retainer
34
. Further, a pressure control valve (not shown) is provided between suction chamber
30
and crank chamber
5
to control the pressure in crank chamber
5
.
In such a variable-displacement inclined plate compressor, when inclined plate
11
rotates in accompaniment with the rotation of drive shaft
6
, the driving force is transmitted to each piston
9
via each shoe
14
, and each piston
9
reciprocally moves in each cylinder bore
8
. By the reciprocal motion of each piston
9
, gas, for example, refrigerant gas, is sucked from suction chamber
30
into a compression chamber through suction port
32
. The gas is compressed in the compression chamber. The compressed gas is discharged into discharge chamber
31
through discharge port
33
. During this operation, the volume of the compressed gas discharged into discharge chamber
31
is controlled by the controlling pressure in crank chamber
5
due to the pressure control valve.
When the above-described compressor is assembled, in order to facilitate the insertion of piston
9
and piston rings attached thereon into cylinder bore
8
of cylinder block
1
, generally front edge
1
b
of cylinder bore
8
may be chamfered as a straight-line tapered, chamfered portion. However, in such a straight-line tapered, chamfered portion, the end of the tapered, chamfered portion and a connecting portion of a cylinder liner may be formed as a relatively sharp corner portion. If such a corner portion exists, the sliding resistance of piston
9
against a radial pressing force, generated particularly when piston
9
moves from the bottom dead center position toward the top dead center position, may increase. Such an increase of the sliding resistance of piston
9
may result in the generation of scratches on the surface of the coating of piston
9
. Further, an excessive load caused by the sliding resistance of piston
9
may adversely affect the control of the inclination of inclined plate
11
, thereby reducing the durability of inclined plate
11
.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an improved structure for a variable-displacement inclined plate compressor that may decrease the sliding resistance of a piston, generated in accompaniment with the reciprocating motion of the piston, and may prevent the piston coating from being scratched, thereby smoothly controlling the inclination angle of an inclined plate by a reduced load.
To achieve the foregoing and other objects, a variable-displacement inclined plate compressor according to the present invention is herein provided. The variable-displacement inclined plate compressor includes a crank chamber defined by a cylinder block and a front housing connected to the cylinder block. The cylinder block has a central bore, into which a drive shaft is inserted, and a plurality of
Hasegawa Yutaka
Hatakeyama Hideharu
Baker & Botts L.L.P.
Ryznic John E.
Sanden Corporation
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