Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2001-10-29
2003-05-20
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S055100, C418S104000
Reexamination Certificate
active
06565340
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an open-type compressor which is built into an air conditioner, refrigerating machine, or the like.
2. Description of the Related Art
Conventionally, air conditioners, refrigerating machines, and the like employ a compressor such as a scroll compressor.
Generally, in scroll compressors, a fixed scroll member which has a base plate and a spiral portion, and a revolving scroll member which also has a base plate and a spiral portion face each other in a manner such that their spiral portions are engaged with each other with a phase difference of 180°, and compression chambers are formed between the scroll members. According to the rotation of the shaft, the revolving scroll member revolves around the axis of the fixed scroll member, so that the capacities of the compression chambers gradually reduce while the positions of the compression chambers gradually move from the peripheral side to the center side of the spiral portions, thereby compressing the relevant gas.
FIG. 2
shows a conventional open-type scroll compressor applied to an air conditioner which is built into a vehicle. In a closed housing H consisting of a front housing
4
and a rear housing
5
, a scroll compression mechanism C is contained, and an electromagnetic clutch MC is provided at the outside of an end portion of the front housing
4
. The scroll compression mechanism C and the electromagnetic clutch MC are directly coupled and joined with each other via a shaft
6
, an end of which protrudes from the front housing
4
.
The shaft
6
is rotatably supported by a main bearing
7
a
and a sub bearing
7
b
, where these bearings are contained in the front housing
4
. Here, the main bearing
7
a
is a needle bearing consisting of an outer ring and a plurality of roller-shaped needles, while the sub bearing
7
b
is a ball bearing consisting of a plurality of balls between outer and inner rings.
Between the main bearing
7
a
and the sub bearing
7
b
, a seal member
34
made of an elastic rubber material is provided, which is also contained in the front housing
4
. Owing to the seal member
34
, leakage of gas or lubricating oil inside the housing H can be prevented. Additionally, the motion of the seal member
34
in the axial direction of the front housing
4
is prohibited by a stopper
34
a.
In the above-explained compressor, when power is transmitted from an external power source (not shown) via a belt to the electromagnetic clutch MC, the shaft
6
rotates and drives the scroll compression mechanism C, so that a refrigerant gas is introduced from a suction hole (not shown) into the closed housing H. This introduced gas is compressed by the scroll compression mechanism C and discharged through a discharge hole (not shown) to the outside of the housing H.
Below, the electromagnetic clutch MC will be explained. An end portion of the shaft
6
of the above-explained scroll compressor is inserted through an attachment hole
41
a
of an armature plate
41
. The armature plate
41
, which is a constituent of the electromagnetic clutch MC, is fastened by using a nut
42
which is screwed and fit onto the end portion of the shaft
4
.
A rotor
43
, which is also a constituent of the electromagnetic clutch MC, is rotatably attached to the front housing
4
, and the rotor
43
rotates by receiving power which is transmitted from an external power source (not shown) via a V-belt (not shown). When a coil (not shown) contained in the rotor
43
of the electromagnetic clutch MC is excited (or energized) by receiving a supplied current, the armature plate
41
is attracted to the rotor
43
, so that the rotational power of the rotor
43
is transmitted to the shaft
6
.
As for a clearance &dgr; between the rotor
43
and the armature plate
41
which are constituents of the electromagnetic clutch MC, if the clearance &dgr; set at the time of assembly is too large, the rotor
43
and the armature plate
41
do not contact each other when the coil is excited, so that the shaft
6
cannot be driven. Conversely, if the clearance &dgr; set at the time of assembly is too small, the armature plate
41
will always contact the rotor during rotation, so that an abnormal sound or abnormal abrasion due to heat (generated by continuous contact) may occur. Therefore, in the assembly, a specific clearance &dgr; (approximately 0.1 to 0.3 mm) must be set between the rotor
43
and the armature plate
41
. Accordingly, in this compressor, a shim
56
for adjusting the clearance is placed between the armature plate
41
and the inner ring of the sub bearing
7
b.
Additionally, in the structure of this compressor, the outer ring of the sub bearing
7
b
contacts a step portion
4
b
formed in the front housing
4
. That is, even if a load for forcing the shaft
6
back towards the inside of the housing H acts via the armature plate
41
after assembly, the movement of the outer ring of the sub bearing
7
b
and the front housing
4
is restricted, thereby preventing the clearance &dgr; from being too small.
Furthermore, the inner ring of the sub bearing
7
b
contacts a stopper
6
b
at the compression mechanism side of the sub bearing
7
b
, where the stopper
6
b
is fit into a groove
6
c
which is formed on the shaft
6
. Accordingly, even if a load for extracting the shaft
6
from the housing H acts via the armature plate
41
after assembly, the movement of the shaft
6
and the inner ring of the sub bearing
7
b
is restricted, thereby preventing the clearance &dgr; from being too large.
In the scroll compressor having the above structure, in the first step of attaching the shaft
6
to the front housing
4
, the main bearing
7
a
is pressed into the front housing
4
, and the shaft
6
is made to fall into the front housing
4
which is positioned in a manner such that the side which will contact the rear housing
5
is set to be the top side. In the next step, the position (or orientation) of the front housing
4
is inverted, and the seal member
34
is fit around the shaft
6
and onto the step portion
4
a
, where the step portion
4
a
is formed in an inner-peripheral face of the front housing
4
. The stopper
34
a
is then attached.
In the following step, the stopper
6
b
is attached to the shaft
6
, and the sub bearing
7
b
is pressed into the inner-peripheral face of the front housing
4
, and simultaneously, the sub bearing
7
b
is fit onto the step portion
4
b
which is formed in the inner-peripheral face of the front housing
4
.
However, in the above-explained compressor, the main bearing
7
a
employs a needle bearing consisting of an outer ring and a plurality of roller-shaped needles. Therefore, when the front housing
4
is inverted after the insertion of the shaft
6
into the front housing
4
, the shaft
6
may fall from the front housing
4
because the main bearing
7
a
has no capability of controlling the position of the shaft
6
in its axial direction. Accordingly, improved working conditions have been desired.
In addition, the stoppers
34
a
and
6
b
are positioned very deep in the inner-peripheral side of the front housing
4
. Therefore, various relevant parts are required, and thus the assembling process is complicated and difficult.
Also in the compressor, the stopper
6
b
is fit into the groove
6
c
which is formed on the shaft
6
, so as to determine the clearance &dgr; of the electromagnetic clutch MC. However, if the stopper
6
b
is not appropriately fit into the groove
6
c
(i.e., having play or the like), the clearance &dgr; of the electromagnetic clutch MC is not fixed. In order to solve this problem, the stopper
6
b
and groove
6
c
must be very accurately processed.
In addition, during the checking or repair of the above compressor which has the stopper
6
b
on the shaft
6
, when the shaft
6
is extracted from the front housing
4
, a portion of the stopper
6
b
is caught by the seal member
34
; thus, it is very difficult to exchange the current shaft for another.
SUMMARY OF THE INVEN
Fujita Katsuhiro
Miura Shigeki
Ukai Tetsuzou
Wada Yasuhiro
Mitsubishi Heavy Industries Ltd.
Vrablik John J.
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