Information
-
Patent Grant
-
6192699
-
Patent Number
6,192,699
-
Date Filed
Tuesday, April 13, 199925 years ago
-
Date Issued
Tuesday, February 27, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
- McDermott; Corrine
- Drake; Malik N.
Agents
- Morgan & Finnegan, L.L.P.
-
CPC
-
US Classifications
Field of Search
US
- 062 2283
- 062 2285
- 417 2222
-
International Classifications
-
Abstract
A compressor includes a transpire passageway exclusively communicated with a suction pressure area, and a throttle constituted by a clearance gap between an inner peripheral surface of an end portion of the shaft hole adjoining a crankcase chamber and an outer peripheral surface of a drive shaft. The transpire passageway has one end passageway portion being opened at a sealed portion sealed by a shaft sealing member disposed in a shaft hole. The transpire passageway has another end passageway portion being opened a suction pressure area.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a variable capacity compressor. The present invention is applicable to refrigerant compressors, in particular, variable capacity compressors having single-head-type pistons.
2. Description of Related Art
There has been a variable capacity compressor which is a wobble type or a swash type and which is mainly employed for vehicle air-conditioners. The variable capacity compressor has a cam plate which is connected with a rotor by way of a hinge mechanism and which is to be oscillated around a fulcrum. The compressor varies a pressure of a crankcase chamber having the cam plate, controlling a force working to the rear surface of the single-head-type piston, and balancing the rear surface and the front surface of the single-head-type piston. Accordingly, the compressor varies an inclination angle of the cam plate around the fulcrum of the cam plate. Namely, the compressor varies a piston-stroke.
The compressor sucks a refrigerant gas, which returns from an exterior refrigerating circuit, from a suction chamber, supplying the sucked refrigerant gas into bores by reciprocating the pistons, compressing the refrigerant gas, and thereby discharging the refrigerant gas into a discharge chamber. As aforedescribed, the compressor has a construction in which the refrigerant gas doesn't pass through the crankcase chamber but directly flows into the bores fitting the corresponding pistons. Accordingly, lubricating ability with respect to sliding parts disposed in the crankcase chamber depends on a blow-by gas leaked to the crankcase chamber. Also, lubricating ability with respect to the sliding parts in the crankcase chamber depends on lubricating oil contained in the refrigerant gas in discharge pressure which is positively supplied into the crankcase chamber during capacity-control to change the pressure in the crankcase chamber.
The conventional compressor is provided with a shaft sealing member arranged for sealing an exposed end portion of the drive shaft. Since the shaft sealing member is arranged in a shaft hole, located apart from the crankcase chamber, the refrigerant gas flowing toward the shaft sealing member is extremely decreased in quantity. As a result, the compressor causes secondary anxiety that the shaft sealing member is heat-deteriorated by shortage of the lubricating and the cooling, and that a clutch slips by gas-leakage.
Japanese Unexamined Patent Publication No. 7-332,250 discloses the compressor in which an appended passageway is disposed in the inside of a drive shaft along a shaft centre thereof. One end passageway portion of the appended passageway is opened in a shaft hole of a front housing, and another end passageway portion of the appended passageway is communicated with a suction pressure area. Also, this publication discloses a technique that the refrigerant gas in the crankcase chamber flows into the suction pressure area by way of the neighborhood of the shaft sealing member.
Judging from view that it is preferable that the shaft sealing member is fully lubricated and cooled, such construction concerning the publication is not satisfied. The reason is that the refrigerant gas—a flow stream from the crankcase chamber to the suction pressure area—is not limited only within the aforesaid appended passageway formed in the inside of the drive shaft. Namely, the refrigerant gas flows into the suction pressure area, not only by way of the aforesaid appended passageway but also by way of another passageway which passes through the radial bearing for supporting the drive shaft arranged in a central hole of a cylinder block.
In other words, since the refrigerant gas flows in two-passageways in the aforedescribed way, less lubricating oil is supplied to the shaft sealing member with the refrigerant gas, as a logical consequence. Also, a pressure reduction is not largely generated at a sealed portion sealed by the shaft sealing member; so, it is apparent that the conventional compressor concerning the aforesaid publication does not cool the shaft sealing member effectively.
SUMMARY OF THE INVENTION
The present invention has been developed in view of the aforementioned circumstances. It is therefore an object of the present invention to provide a variable capacity compressor which improves endurance of a shaft sealing member by designating a transpire passageway connected with a crankcase chamber and a suction pressure area.
In the first aspect of the present invention, a variable capacity compressor comprises: (1) a cylinder block including a plurality of bores arranged therein, constituting a body of the compressor, and having a front end and a rear end; (2) a front housing including a shaft hole, and a crankcase chamber disposed in the inside thereof, the front housing closing the front end of the cylinder block, and the crankcase chamber having a rotor and a hinge mechanism; (3) a drive shaft rotatably supported by the cylinder block and the front housing, the drive shaft having an end portion disposed in the shaft hole of the front housing; (4) a shaft sealing member disposed in the shaft hole between the drive shaft and the front housing for sealing the shaft hole of the front housing; (5) a rear housing including a suction pressure area and a discharge pressure area, and the rear housing closing the rear end of the cylinder block; (6) a cam plate connected to be inclined with respect to the drive shaft, and connected with the rotor by way of the hinge mechanism to synchronously be rotated with the drive shaft; (7) a plurality of pistons associated with the cam plate for reciprocating in each of the bores; (8) a capacity control valve for controlling a pressure of the crankcase chamber by supplying a discharge pressure from the discharge pressure area to the crankcase chamber, the capacity control valve for varying an inclination angle and a piston stroke on the basis of a differential pressure between a suction pressure and the pressure of the crankcase chamber; and (9) the improvement comprising;
(9-1) a transpire passageway exclusively communicated with a suction pressure area, having one end passageway portion being opened at a sealed portion being sealed by the shaft sealing member disposed in the shaft hole, and having another end passageway portion being opened the suction pressure area; and
(9-2) a throttle constituted by a clearance gap between an inner peripheral surface of an end portion of the shaft hole adjoining the crankcase chamber and an outer peripheral surface of the drive shaft.
In the first aspect of the present invention, the sealed portion sealed by the shaft sealing member is communicated with the crankcase chamber by way of the shaft hole of the front housing. Also, the sealed portion sealed by the shaft sealing member is communicated with the suction pressure area, which indicates a lower pressure, by the transpire passageway. Accordingly, an exclusive flow stream is generated in the refrigerant gas of the crankcase chamber, the exclusive flow stream moves toward the transpire passageway by way of the shaft sealing member because of a pressure difference. Therefore, the shaft sealing member is effectively lubricated and cooled by the flow stream.
In the case of a compressor which controls a capacity by controlling a pressure of the crankcase chamber, namely, by increasing a pressure of the crankcase chamber, the refrigerant gas is positively supplied to the crankcase chamber, and accordingly, the shaft sealing member is more effectively lubricated and cooled. Also, the throttle, communicated with the transpire passageway, is constituted by a clearance gap between an inner peripheral surface of an end portion of the shaft hole adjoining the crankcase chamber and an outer peripheral surface of the drive shaft. Therefore, the throttle decreases a back pressure of the shaft sealing member to the same pressure as the suction pressure area, thereby remarkably decreasing load applied to the shaft sealing member, and thereby obtaining a cooling ability caused by a pressure reduction resulting from the throttle.
In the first aspect of the present invention, the compressor has the transpire passageway being exclusively communicated with a suction pressure area by way of the shaft sealing member, and the compressor has the throttle formed at the end portion of the shaft hole which corresponds with a starting location of the transpire passageway and which adjoins the crankcase chamber. In the first aspect of the present invention, the shaft sealing member is considerably improved in endurance.
In the second aspect of the present invention, since the transpire passageway passes through the body of the front housing, the body of the cylinder block, and the body of the rear housing; so, the transpire passageway is concisely formed as compared with a manner that a transpire passageway is attached at the outside the compressor body.
In the third aspect of the present invention, a radial bearing having an outer ring is inserted at the end portion of the shaft hole adjoining the crankcase chamber, and the throttle is constituted by a clearance gap between the outer ring of the radial bearing and the drive shaft. Accordingly, the third aspect of the present invention effectively contributes to the lubricating of the radial bearing and the cooling of the radial bearing, without affecting the forming of the front housing and assembling of parts constituting the compressor.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the present invention and many of its advantages will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings and detailed specification, all of which forms a part of the disclosure:
FIG. 1
illustrates a cross sectional view showing a variable capacity compressor;
FIG. 2
illustrates an enlarged cross sectional view showing a capacity control valve disposed in the variable capacity compressor; and
FIG. 3
illustrates an enlarged cross sectional view showing the neighborhood of a shaft hole.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Having generally described the present invention, a further understanding can be obtained by reference to the specific preferred embodiment which is provided herein for purposes of illustration only and are not intended to limit the scope of the appended claims.
Preferred Embodiment
A compressor according to the present invention will be hereinafter described with reference to a Preferred Embodiment thereof.
As shown in
FIG. 1
, there is a cylinder block
1
having a front end If and a rear end
1
r. The front end
1
f of the cylinder block
1
is closed by a front housing
2
, and the rear end
1
r of the cylinder block
1
is closed by way of a valve plate
4
by a rear housing
3
. These parts are connected together by bolts
21
. The cylinder block
1
and the front housing
2
form a crankcase chamber
5
in which a drive shaft
6
extends in a direction of the shaft centre. The drive shaft
6
is rotatably supported by radial bearings
7
a,
7
b.
The front end portion
6
f
of the drive shaft
6
is to be connected with a vehicle engine by way of an electro-magnetic clutch and a transmitting mechanism. Also, the cylinder block
1
has a plurality of bores
8
which are arranged around the drive shaft
6
. The compressor has pistons
9
which are fitted in each of bores
8
to be reciprocated respectively.
The crankcase chamber
5
has a rotor
10
which is connected with the drive shaft
6
, and a thrust bearing
11
is arranged between the rotor
10
and the front housing
2
. The rotor
10
, therefore, is capable of rotating synchronously with the drive shaft
6
. The crankcase chamber
5
has a cam plate
12
which is located on one side of the rotor
10
and is rotated integrally with the drive shaft
6
via the rotor
10
. The crankcase chamber
5
has an urging spring
13
which is disposed between the rotor
10
and the cam plate
12
and which usually urges the cam plate
12
backwards.
The cam plate
12
has sliding surfaces
12
a
which are opposite to each other to has a flatness and which are formed in the outer peripheral portion of the cam plate
12
. The sliding surface
12
a
comes in contact with shoes
14
. Each of shoes
14
exhibits a hemisphere shape having a convex spherical surface
14
x
which is engaged with a concave spherical surface
9
x
of the piston
9
.
The compressor has a pair of brackets
12
b
projecting from the cam plate
12
at a location which is set inner than the sliding surface
12
a
and which faces the rotor
10
. The pair of brackets
12
b
straddle a top dead centre “T” of the cam plate
12
. One end portion of each of guiding pins
12
c
is fixed to the bracket
12
b.
The ball portion
12
d
is formed at the other end portion of the guiding pin
12
c.
So, a hinge mechanism “K” is constituted by the pair of brackets
12
b,
the corresponding guiding pins
12
c,
and the ball portions
12
d.
The bracket
12
b,
the guiding pin
12
c,
and the ball portion
12
d
are plural, respectively.
The cam plate
12
has a bent through-hole
20
which is formed at the central portion of the cam plate
12
. The bent through-hole
20
permits the cam plate
12
to be displaced on the drive shaft
6
. There is a counter weight
15
installed by rivets at the bottom dead centre area of the cam plate
12
. The counter weight
15
is outwardly extended from the centre line of the drive shaft
6
. The counter weight
15
covers the sliding surface
12
a,
while avoiding the shoes
14
facing the rotor
10
.
The cam plate
12
has a front end surface
12
e
which is centrally disposed in a radius direction of the cam plate
12
. The front end surface
12
e
of the cam plate
12
comes in contact with the rear end surface
10
a
of the rotor
10
; so, the cam plate
12
is regulated in its maximum angle. On the other hand, the cam plate
12
has a seat hole portion which comes in contact with a circlip
22
fixed onto the drive shaft
6
; so, the cam plate
12
is regulated in its minimum angle.
Also, the rotor
10
has a pair of supporting arms
17
constituting the remnants of the aforesaid hinge mechanism “K”. The supporting arm
17
is disposed at the upper portion of the rotor
10
. The supporting arm
17
projects backwards along an axial direction of the drive shaft
6
. The supporting arm
17
is arranged with the guiding pin
12
c
therein. The top end of the supporting arm
17
has a guide hole
17
a.
The guide hole
17
a
is arranged to approach the centre line of the drive shaft
6
from the outside of the drive shaft
6
, and the guide hole
17
a
is parallel to an imaginary plane decided by the centre line of the drive shaft
6
and the top dead centre “T” of the cam plate
12
. Orientation of the guide hole
17
a
is set to immovably hold the top dead centre of the piston
9
, regardless of the inclination angles of the cam plate
12
. The ball portion
12
d
is slidablly inserted into the guide hole
17
a.
The rear housing
3
has a suction chamber
30
and a discharge chamber
31
. The valve plate
4
has inlet ports
32
and outlet ports
33
opened to face the respective bores
8
. The valve plate
4
and the end surface
9
w
of the pistons
9
are to form respective compression chambers
9
p
which are communicated with the suction chamber
30
by way of the inlet ports
32
and which communicated with the discharge chamber
31
by way of the outlet ports
33
. The valve plate
4
is provided with suction valves (not shown) for opening and closing the respective inlet ports
32
, and discharge valves (not shown) for opening and closing the respective outlet ports
33
. The rear housing
3
has a suction hole
34
which communicates the suction chamber
30
with the outer refrigerant circuit (not shown). The suction hole
34
and the suction chamber
30
work as the suction pressure area of the present invention.
The rear housing
3
has a capacity controls valve
50
built-in for controlling a pressure of the crankcase chamber
5
in response to cooling demand. The compressor has: (1) a pressure-measuring passageway
97
communicated with the suction chamber
30
; (2) a pressure-introducing passageway
96
communicated with the discharge chamber
31
; and (3) a supplying passageway
95
having an opening
95
c
communicated with the crankcase chamber
5
. The capacity control valve
50
has ports which are communicated with the pressure-measuring passageway
97
, the pressure-introducing passageway
96
, and supplying passageway
95
, respectively.
The capacity control valve
50
shown in
FIG. 2
has a diaphragm
53
which is arranged by holding members
54
(
54
a,
54
b
) between a valve main body
51
and a sleeve
52
. The diaphragm
53
works as a pressure sensitive mechanism. The sleeve
52
has an opening which is screwed by a lid plug
55
. The valve
50
has an atmospheric chamber
70
which is formed by the sleeve
52
, the lid plug
55
, the diaphragm
53
, and the holding member
54
a.
The sleeve
52
has pores
52
a
which are communicated with the atmospheric chamber
70
by a backlash
55
x
between the lid plug
55
and the sleeve
52
so as to keep the atmospheric chamber
70
an atmospheric pressure. The atmospheric chamber
70
stores an urging spring
56
having an urging force. The urging spring
56
is disposed between lid plug
55
and a presser
57
having a hat-shape in a cross sectional view. The presser
57
urged by the urging spring
56
is connected to a presser
59
having a ring shape via a ball
58
, so the urging force of the spring
56
is transmitted to the diaphragm
53
.
The valve main body
51
has a suction pressure chamber
71
which is formed between the diaphragm
53
and the holding member
54
b.
The suction pressure chamber
71
is communicated with the pressure-measuring passageway
97
and the suction chamber
30
by a port
71
a
formed in the valve main body
51
. As a result, a suction pressure is supplied to the suction pressure chamber
71
by the pressure-measuring passageway
97
. The suction pressure chamber
71
contains a presser
61
which comes in contact with the diaphragm
53
and which has a “II” shape in a cross sectional view. The capacity control valve
50
has an urging spring
62
which has an urging force and which is disposed between the presser
61
and the bottom surface of the suction pressure chamber
71
. The presser
61
is connected with one end portion
63
u
of the rod
63
capable of sliding in the valve main body
51
. The valve
50
has a ball valve
65
connected with the other one end portion
63
d
of the rod
63
.
Also, the valve
50
has a discharge pressure chamber
72
formed at the end side of the valve main body
51
. The discharge pressure chamber
72
contains a valve seat
72
m
at which the ball valve
65
is to be seated. The valve main body
51
has a lid
60
which closes the end opening of the discharge pressure chamber
72
. The lid
60
has a port
72
a
formed to communicate with the discharge chamber
31
by way of the pressure-introducing passageway
96
, thereby introducing a discharge pressure of the discharge chamber
31
into the discharge pressure chamber
72
of the control valve
50
. The discharge pressure chamber
72
contains a presser
66
, and an urging spring
67
which urges the presser
66
between the presser
66
and the lid
60
. The presser
66
comes in contact with the ball valve
65
. The urging spring
67
has a spring force for urging the ball valve
65
.
On the other hand, the valve main body
51
has a port
73
a
communicated with the supplying passageway
95
. The port
73
a
is communicated with the discharge pressure chamber
72
by way of a valve hole
72
b
formed at the surroundings of the rod
63
. The lid
60
has a filter
60
a
facing the pressure-introducing passageway
96
.
Nextly, the transpire passageway
41
showing the feature of the present invention will be further explained hereinafter.
The front housing
2
has a shaft sealing member
40
in the shaft hole
2
a
thereof for sealing the end portion
6
f
of the drive shaft
6
. The shaft sealing member
40
has a sealing lip
40
m
for coming into contact with the drive shaft
6
, and the shaft sealing member
40
is formed of polymer based material, such as rubber or resin.
A radial bearing
7
a,
a needle bearing, is arranged in the rear side with respect to the shaft sealing member
40
, namely, in the hole end portion
5
m
adjoining the crankcase chamber
5
. So, the radial bearing
7
a
faces the crank chamber
5
by way of the rotor
10
. As shown in
FIG. 3
, the radial bearing
7
a
has an outer ring
7
k
having a channel ring space
7
r,
a plurality of rollers
7
m
arranged in a circumferential direction in the channel ring space
7
r,
and a cage
7
n
for holding the rollers
7
m
in the outer ring
7
k.
As shown in
FIG. 3
, the outer ring
7
k
faces an inner peripheral surface
5
x
of the hole end portion
5
m
of the front housing
2
. The rollers
7
m
face an outer peripheral surface
6
x
of the shaft
6
. As shown in
FIG. 3
showing a cross sectional view, the outer ring
7
k
has a ring portion
7
k
1
formed along the axial direction and end ring portions
7
k
2
formed inwardly along the radius direction from ends of the ring portion
7
k
1
.
The compressor has the transpire passageway
41
. As shown in
FIG. 1
, the transpire passageway
41
is formed, in sequence, through the body of the front housing
2
, the body of the cylinder block
1
, and the body of the rear housing
3
so as to connect to the suction hole
34
. The transpire passageway
41
has one end passageway portion
41
s
which is opened between the radial bearing
7
a
and the shaft sealing member
40
, namely, which is opened at the sealed portion
40
p
being sealed by the shaft sealing member
40
in the shaft hole
2
a.
Also, the transpire passageway
41
has another end passageway portion
41
t
opened at the suction hole
34
formed in the rear housing
3
.
As shown in
FIG. 1
, the transpire passageway
41
has a passageway
41
o
formed in the front housing
2
along a radius direction, a passageway
41
p
formed in the body wall of the front housing
2
along an axial direction, a passageway
41
q
formed in the body wall of the cylinder block
1
along an axial direction, and a passageway
41
r
formed in the body wall of the rear housing
3
along an axial direction.
A throttle
42
is constituted by a clearance gap between the inner peripheral surface
5
x
of the hole end portion
5
m
adjoining the crankcase chamber
5
and an outer peripheral surface
6
x
of the drive shaft
6
.
As shown in
FIG. 3
, in the present embodiment, the throttle
42
is formed by a clearance gap between the end ring portions
7
k
2
of the outer ring
7
k
of the radial bearing
7
a
and the outer peripheral surface
6
x
of the drive shaft
6
.
The transpire passageway
41
is to exclusively extract the refrigerant gas of the crankcase chamber
5
into the suction pressure area, the suction hole
34
. The refrigerant gas of the crankcase chamber
5
is not extracted by way of other passageways.
The compressor of the present embodiment is constituted in the aforesaid construction. A force “F
1
” is the resultant force adding a pressure of the suction pressure chamber
71
and the spring force of the urging spring
62
. A force “F
2
” is the resultant force adding an atmospheric pressure of the atmospheric chamber
70
and the spring force of the urging spring
56
. When the compressor is stopped, a pressure in the compressor is balanced at a higher pressure than a predetermined suction-pressure value, accordingly, the force “F
1
” is larger than the force “F
2
”, and the force “F
1
” works to the diaphragm
53
. The rod
63
, therefore, is displaced in a direction “Y
1
” in
FIG. 2
, the ball valve
65
is seated onto the valve seat
72
m
to close the valve hole
72
b,
closing the supplying passageway
95
, thereby closing the communication between the discharge chamber
31
and the crankcase chamber
5
.
From such situation, when the drive shaft
6
is rotated by way of a electro-magnetic clutch, the cam plate
12
is rotated with oscillation by way of the rotor
10
and the hinge mechanism “K”, reciprocating the piston
9
to start compression work. In the early stage of the compression work, the suction pressure and temperature of the vehicle room are generally higher, the capacity control valve
50
keeps the supplying passageway
95
closed, as above-mentioned. Thus, the blow-by gas returned to the crankcase chamber
5
during compression work flows into the suction chamber
30
by way of the transpire passageway
41
. Thus, a differential pressure between the pressure of the crankcase chamber
5
and suction pressure is kept lower than the predetermined suction-pressure value; so, the pistons
9
are driven to exhibit a maximum piston-stroke; namely: the compressor is driven at the full capacity.
When the compressor is continuously driven at the full capacity, the temperature of the vehicle room becomes gradually lower, the suction pressure becomes lower than the predetermined suction-pressure value, and thereby the force “F
1
” is defeated by the force “F
2
”. Accordingly, this operates the diaphragm
53
to the presser
61
, displacing the rod
63
in a direction “Y
2
”, further detaching the ball valve
65
from the valve seat
72
m.
Also, this opens the valve hole
72
b,
the supplying passageway
95
, further opening the pressure-introducing passageway
96
, the port
72
a,
the discharge pressure chamber
72
, and the port
73
a.
So, the supplying passageway
95
introduces the high pressure refrigerant gas of the discharge chamber
31
into the crankcase chamber
5
, thereby increasing the pressure of the crankcase chamber
5
.
When the pressure of the crankcase chamber
5
becomes higher to increase the differential pressure between the pressure of the crankcase chamber
5
and the suction pressure, the compressor decreases the inclination angle of the cam plate
12
and the stroke of the piston
9
, and the compressor is shifted into a small capacity mode. Subsequently, the capacity control valve
50
closes the valve hole
72
b
by ball valve
65
, and closing the supplying passageway
95
again after the suction pressure increases again in response to the increase in temperature.
The capacity control of the compressor is carried out in the above-mentioned way. When cooling demand is large, only the blow-by gas flows into the crankcase chamber
5
. When cooling demand is small, the high pressure refrigerant gas is positively supplied into the crankcase chamber
5
by way of the capacity control valve
50
and the supplying passageway
95
.
In either case, a part of the high pressure refrigerant gas flows along the throttle
42
which is disposed at the hole end portion
5
m
of the shaft hole
2
a
of the front housing
2
; so, a part of the high pressure refrigerant gas flows toward the suction pressure area, namely the suction hole
34
, exclusively by way of the transpire passageway
41
adjoining the sealed portion
40
p
sealed by the shaft sealing member
40
—a feature of the present invention.
In other words, the exclusive flow stream is generated in the refrigerant gas in the crankcase chamber
5
by the differential pressure, passing through the vicinity of the shaft sealing member
40
. The exclusive flow stream, whose quantity is large, lubricates and cools the shaft sealing member
40
effectively.
In the case where the compressor increases the pressure of the crankcase chamber
5
so as to control the capacity, the high pressure refrigerant gas containing oil is positively supplied into the crankcase chamber
5
in controlling the capacity. This further generates the gas-flow stream passing through the vicinity of the shaft sealing member
40
. So, the shaft sealing member
40
is effectively lubricated and cooled.
In the present embodiment, the throttle
42
is constituted by the gap between the inner peripheral surface
5
x
of the hole end portion
5
m
adjoining the crankcase chamber
5
and the outer peripheral surface
6
x
of the drive shaft
6
, the back pressure “Px” (shown in
FIG. 1
) with respect to the shaft sealing member
40
is decreased to equal to the pressure of the suction pressure area, the suction hole
34
.
Accordingly, the present embodiment reduces the load applied to the seal portion, and it obtains a cooling ability on the basis of the reduced pressure caused by the throttle
42
.
Also, the throttle
42
is constituted by the clearance gap between the drive shaft
6
and the outer ring
7
k
of the radial bearing
7
a
which is disposed at the hole end portion
5
m
adjoining the crankcase chamber
5
in the shaft hole
2
a.
Accordingly, the present embodiment additionally obtains the lubricating ability and cooling effect with respect to the radial bearing
7
a,
without affecting the forming of the front housing
2
and the assembling of the parts.
In another embodiment of the present invention, it is possible that decreasing the inner diameter of hole end portion
5
m
of the shaft hole
2
a
constitutes another throttle.
Claims
- 1. A variable capacity compressor, comprising:a cylinder block including a plurality of bores arranged therein, constituting a body of said compressor, and having a front end, and a rear end; a front housing including a shaft hole, and a crankcase chamber disposed in the inside thereof, said front housing closing said front end of said cylinder block, and said crankcase chamber having a rotor and a hinge mechanism; a drive shaft rotatably supported by said cylinder block and said front housing, said drive shaft having an end portion disposed in said shaft hole of said front housing; a shaft sealing member disposed in said shaft hole between said drive shaft and said front housing for sealing said shaft hole of said front housing; a rear housing including a suction pressure area and a discharge pressure area, and said rear housing closing said rear end of said cylinder block; a cam plate connected to be inclined with respect to said drive shaft, and connected with said rotor by way of said hinge mechanism to synchronously be rotated with said drive shaft; a plurality of pistons associated with said cam plate for reciprocating in each of said bores; a capacity control valve for controlling a pressure of said crankcase chamber by supplying a discharge pressure from said discharge pressure area to said crankcase chamber, said capacity control valve for varying an inclination angle and a piston stroke on the basis of a differential pressure between a suction pressure and said pressure of said crankcase chamber; and the improvement comprising; a transpire passageway exclusively being communicated with said suction pressure area, having one end passageway portion being opened at a sealed portion being sealed by said shaft sealing member disposed in said shaft hole, and having another end passageway portion being opened said suction pressure area; and a throttle constituted by a clearance gap between an inner peripheral surface of an end portion of said shaft hole adjoining said crankcase chamber and an outer peripheral surface of said drive shaft.
- 2. A variable capacity compressor according to claim 1, wherein said transpire passageway passes through an inside of a body of said front housing, an inside of a body of said cylinder block, and an inside of a body of said rear housing, for communicating with said suction pressure area.
- 3. A variable capacity compressor according to claim 1, wherein a radial bearing having an outer ring is inserted at said end portion of the shaft hole adjoining said crankcase chamber, said radial bearing for rotatably supporting said drive shaft, and said throttle is constituted by a clearance gap between said outer ring and said outer peripheral surface of said drive shaft.
- 4. A variable capacity compressor according to claim 3, wherein said radial bearing and said shaft sealing member are adjacent to each other in said shaft hole, and said radial bearing faces said crankcase chamber.
- 5. A variable capacity compressor according to claim 4, wherein said one end passageway portion of said transpire passageway is opened between said radial bearing and said shaft sealing member in said shaft hole.
- 6. A variable capacity compressor according to claim 1, wherein said crankcase chamber is controlled by said capacity control valve in such a manner that refrigerant gas containing lubricating oil is supplied into said crankcase chamber.
- 7. A variable capacity compressor according to claim 1; wherein said radial bearing has an outer ring having a channel ring space and facing said inner peripheral surface of said end portion of the shaft hole adjoining said crankcase chamber, and a plurality of rollers arranged in a peripheral direction in said channel ring space and rotatably facing said outer peripheral surface of said drive shaft; andwherein said throttle is constituted by a clearance gap between said outer ring of said radial bearing and said outer peripheral surface of said drive shaft.
- 8. A variable capacity compressor according to claim 1; wherein said compressor is used for an air-conditioner, said capacity control valve controls a pressure of said crankcase chamber in response to a cooling demand; andwherein said compressor has a supplying passageway communicated with said crankcase chamber and said capacity control valve, and when said cooling demand is small, high pressure refrigerant gas is supplied into said crankcase chamber by way of said supplying passageway by said capacity control valve.
- 9. A variable capacity compressor according to claim 8; wherein said capacity control valve has a discharge pressure chamber communicated with said discharge chamber of said rear housing, a valve hole formed between said discharge pressure chamber and said supplying passageway, and a valve body for closing and opening said valve hole; andwherein when said cooling demand is small, said valve body opens said valve hole to supply said high pressure refrigerant gas of said discharge chamber of said rear housing into said crankcase chamber by way of said valve hole and said supplying passageway.
Priority Claims (1)
Number |
Date |
Country |
Kind |
10-107540 |
Apr 1998 |
JP |
|
US Referenced Citations (9)
Foreign Referenced Citations (5)
Number |
Date |
Country |
19633533 A1 |
Feb 1997 |
DE |
19644431 A1 |
Apr 1997 |
DE |
0711918 A2 |
May 1996 |
EP |
3-6875 |
Feb 1991 |
JP |
7-332250 |
Dec 1995 |
JP |