Expansible chamber devices – Relatively movable working members – Interconnected with common rotatable shaft
Reexamination Certificate
2001-09-28
2003-05-27
Look, Edward K. (Department: 3745)
Expansible chamber devices
Relatively movable working members
Interconnected with common rotatable shaft
C384S590000, C384S620000, C384S606000
Reexamination Certificate
active
06568312
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a variable displacement swash plate type compressor for use in an air conditioner of an automobile, and more particularly, to a thrust bearing structure for supporting a driving shaft thereof in an axial direction wherein a correlation between an inner and an outer diameters of a stationary and a driving races and a center bore and an outer diameter of a driving shaft is specified.
2. Description of the Related Art
In general, a variable displacement swash plate type compressor is used for controlling an amount of a fluid to be ejected by increasing or decreasing a piston stroke depending on an inclination angle of a swash plate.
Referring to
FIG. 1
, constitution and operation of a general variable displacement swash plate type compressor
1
will be described. The variable displacement swash plate type compressor
1
comprises a cylinder block
2
including a center bore
4
and a plurality of cylinder bores
6
radially formed around the center bore
4
, both sides of the cylinder block
2
being hermetically covered with a front housing
8
and a rear housing
10
. Between the cylinder block
2
and the front housing
8
, an airtight crank chamber
12
is formed, and between the back end of the cylinder block
2
and the rear housing
10
, a valve plate
14
is interposed. Further, the rear housing
10
is provided with an inlet and an outlet for a refrigerating gas, a suction chamber
16
and a discharge chamber
18
. The refrigerants in the suction and the discharge chambers
16
and
18
flow into/from each of the cylinder bore
6
through a suction and a discharge valve mechanisms. A driving shaft
20
is installed at a central portion of the compressor
1
, the driving shaft extending through the front housing
8
into the cylinder block
2
. Further, the driving shaft
20
is rotatably supported by radial bearings
22
which are installed at the front housing
8
and the cylinder block
2
, and one end thereof is axially supported by a support to prevent the driving shaft
2
from moving the axial direction. The cylinder block
2
is coupled to the front and the rear housings
8
and
10
by a through bolt
24
. In the crank chamber
12
, a rotor
26
is fixedly mounted around the driving shaft
20
extending across the crank chamber
12
in such a manner that the rotor
26
rotates together with the driving shaft
20
. A swash plate
28
is rotatably installed around the driving shaft
20
. Further, between the driving shaft
20
and the swash plate
28
a spherical sleeve may be interposed. In this case, the swash plate
28
is rotatably supported by an outer surface of the spherical sleeve. In
FIG. 1
, the swash plate
28
is positioned at a maximum angle of the inclination. In this case, a stop surface
32
a
of a protuberance
32
of the swash plate
28
comes into contact with the rotor
26
and a spring
30
is compressed in the maximum state. Therefore, the rotor
26
confines a maximal angle of the inclination of the swash plate. Further, the driving shaft
20
is provided with a stopper
34
for defining the minimum angle of the inclination of the swash plate
28
.
Further, the swash plate
28
and the rotor
26
are connected with each other through a hinge mechanism so that they rotate together. To be more specific, a support arm
36
protrudes outwardly from one side of the rotor
26
in the axial direction of the driving shaft
20
, and an arm
38
extends from one side of the swash plate
28
to the support arm
36
. The arms
36
and
38
are connected to each other through a pin
40
.
A piston
42
is slidably disposed in each of the cylinder bores
6
, each of the pistons
42
having a body
44
slidably installed in the cylinder bore
6
and a bridge
46
. The bridge
46
of the piston
42
has a recess
48
in which a portion of the outer periphery of the swash plate is positioned. The hemispherical shoe
50
are installed at the shoe pocket
52
formed in the bridge
46
of the piston
42
, and slidably engaged with both sides of the outer peripheral portion of the swash plate
28
. Consequently, during the rotation of the driving shaft
20
, the swash plate
28
rotates also, and the rotational movement of the swash plate
28
is converted into the reciprocation of the piston through the shoe
50
. The piston
42
has at its one end a cutout portion
54
. The cutout portion
54
functions to prevent the swash plate
28
and the body
44
of the piston
42
from coming into contact with each other when the piston
42
reaches a bottom dead point.
With reference to
FIG. 2
, the support mechanism
56
for axially supporting the driving shaft
20
is positioned in the center bore
4
of the cylinder block
2
, and includes a driving race
60
closely fixed at one side of a thrust bearing
58
, which is provided around the driving shaft
20
in the center bore
4
of the cylinder block
2
, so as to rotate together with the driving shaft
20
, and a stationary race
62
closely fixed at the other side of a thrust bearing
58
so as to be stationary independent on the rotation of the driving shaft
20
. The support mechanism
56
further includes a resilient member
64
which supports the driving shaft
20
by axially supporting the thrust bearing
58
and races
60
,
62
.
In such a compressor, since the driving race
60
should be rotated together with the driving shaft
20
, its inner diameter (d1) has to be almost the same as an outer diameter (d2) of the driving shaft
20
, and since the stationary race
62
should be kept stationary in the center bore
4
, its outer diameter (D3) has to be almost the same as a diameter (d4) of the center bore
4
. However, in a prior art compressor, a distance (Lr1) between the inner diameter (d3) of the stationary race
62
and the outer diameter (d2) of the driving shaft
20
is smaller than a distance (Lr2) between the outer diameter (D3) and a surface
4
a
of the center bore
4
. Accordingly, as shown in
FIG. 3
, the stationary race
66
may be eccentrically assembled with the driving shaft
20
by a predetermined distance, e.g., &lgr; (he maximum eccentric distance) during assembling process. In this case, an inner periphery of the stationary race
66
and an outer periphery of the driving shaft
20
come into contact with each other to generate a frictional heat, thereby deteriorating durability of the compressor. Further, abrasive particle due to the contact (c) between the stationary race
66
and the driving shaft
20
disturbs the flow of the refrigerants, thereby lowering the cooling performance of the air conditioner.
SUMMARY OF THE INVENTION
It is, therefore, a primary object of the present invention to provide a thrust bearing structure capable of the above-mentioned problems, the thrust bearing structure supporting a driving shaft of a variable displacement swash plate type compressor having a stationary and a driving race.
Another object of the present invention is to provide the thrust bearing structure capable of reducing a noise due to friction between the driving shaft and the race.
Still another object of the present invention is to provide the thrust bearing structure capable of improving an assembling process of the races for use in the driving shaft of the variable displacement swash plate type compressor.
In accordance with one aspect of the present invention, there is provided a thrust bearing structure in which a distance between an inner diameter of the stationary race and an outer diameter of the driving shaft is greater than a distance between an outer diameter of the stationary race and a surface of the center bore.
In accordance with another aspect of the present invention, there is provided a thrust bearing structure in which a distance between an outer periphery of the driving race and a surface of the center bore is greater than a distance between an inner periphery of the driving race and an outer periphery of the driving shaft, and a distance between an outer periphery of the stationa
Ahn Hew-nam
Park Tae-young
Greenblum & Bernstein P.L.C.
Halla Climate Control Corporation
Kershteyn Igor
Look Edward K.
LandOfFree
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