Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
1999-02-22
2001-02-27
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S149000, C417S902000
Reexamination Certificate
active
06193485
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a sealing structure of a casing, and more particularly, to a sealing structure between a partition member and a casing in the case where there are both a high pressure chamber and a low pressure chamber divided by the partition member in the casing.
BACKGROUND ART
FIGS. 4 and 5
show a sealing structure of a casing of a conventional scroll fluid machine.
FIG. 4
shows a scroll fluid machine disclosed in Japanese Patent Publication No. 6-65880 (Japanese Patent Laying-Open No. 60-190690), and
FIG. 5
shows a scroll fluid machine disclosed in Japanese Patent Laying-Open No. 7-310677. For the purposes of convenience, components in
FIGS. 4 and 5
related to those of the invention of the present application have reference characters allotted, and the labels thereof will be appropriately altered corresponding to the components of the invention of the present application.
Referring to
FIG. 4
, the casing of the scroll fluid machine is constituted by an upper casing
2
a
and a lower casing
2
b.
A fixed scroll
3
, a movable scroll
4
, a housing
5
, a crank shaft
6
, and a motor
22
are incorporated within the casing.
A compression chamber
15
for compressing gas refrigerant is formed of fixed scroll
3
and movable scroll
4
. Movable scroll
4
includes a boss unit
4
a
and an outlet
4
b
for discharging compressed gas refrigerant. Crank shaft
6
includes an eccentric unit
6
a
into which boss unit
4
a
is inserted. A bearing metal
7
a
is provided between boss unit
4
a
and eccentric unit
6
a.
Motor
22
includes a rotor
21
and a stator
20
. Crank shaft
6
is inserted inside rotor
21
. The peripheral portion of housing
5
is sandwiched between upper housing
2
a
and lower housing
2
b.
An O-ring
24
for sealing is attached at the boundary between housing
5
and upper casing
2
a.
A suction pipe
10
and a discharge pipe
23
are attached to the casing. The compressed gas refrigerant is discharged outside according to the open arrow in FIG.
4
.
Referring to the conventional art of
FIG. 5
, a notch stepped portion
25
is provided in upper casing
2
a
to receive a peripheral portion
5
a
of housing
5
. The lower end of upper casing
2
a
is fixed to the outer circumferential face of lower casing
2
b
by a welding portion
13
. Housing
5
is secured by a spot welding portion
13
a.
In the conventional art of
FIG. 4
, an O-ring
24
is provided between housing
5
and upper casing
2
a.
The usage of O-ring
24
induces the problem of increase in cost. In the case of
FIG. 4
, reduction in the spacing in the casing is a matter of concern since the open end of upper casing
2
a
is fitted into the inner side of the opening end of lower casing
2
b.
In contrast, the problem of increase in cost due to usage of an O-ring is not encountered in the conventional case of
FIG. 5
since no O-ring is used. Furthermore, the problem of reduction in the spacing in the casing is eliminated since upper casing
2
a
is outer-fitted to lower casing
2
b.
However, a welding process is carried out with respect to upper casing
2
a
and lower casing
2
b.
There is a possibility that housing
5
is deformed caused by deformation of upper and lower casings
2
a
and
2
b
by the welding process.
DISCLOSURE OF THE INVENTION
The present invention is directed to solve the above problems. An object of the present invention is to provide a sealing structure of a casing that can have increase in cost suppressed by providing sealing between the casing and a housing member abutted on the inner wall of the casing without using an O-ring, and that can have deformation of the housing member caused by shrinkage-fitting or press-fitting and welding suppressed.
According to a sealing structure of a casing of the present invention, the casing includes a first casing, a second casing that is outer-fitted to the outer circumferential face of the first casing, and a housing member held by the first casing and having the outer circumferential face abutted on the inner wall of the second casing. A convex portion is formed at at least one of the outer circumferential face of the housing member and the inner circumferential face of the second casing . The second casing is shrinkage-fitted or press-fitted to the housing member. By this shrinkage-fitting or press-fitting, the convex portion is deformed to provide sealing between the inner circumferential face of the second casing and the outer circumferential face of the housing member.
As described above, the second casing is shrinkage-fitted or press-fitted to the housing member. Accordingly, the convex portion is deformed. The outer circumferential face of the housing member and the inner wall of the second casing can abut each other hermetically to allow sealing between the outer circumferential face of the housing member and the inner wall of the casing. As a result, it is not necessary to provide an O-ring between the outer circumferential face of the housing member and the inner wall of the casing. Therefore, the cost can be reduced. Furthermore, since a convex portion is selectively provided at at least the outer circumferential face of the housing member or the inner wall of the second casing, the convex portion is pressed by the outer circumferential face or the inner wall at the time of shrinkage-fitting or press-fitting to be deformed with priority. More specifically, the compressive stress exerted to the housing member in the shrink-fitting or press-fitting process can be made to concentrate at the convex portion. Accordingly, the amount of deformation of the housing member itself caused by the shrinkage-fitting or press-fitting can be reduced effectively.
The above-described casing is preferably a casing of a scroll fluid machine in which both a high pressure chamber and a low pressure chamber are present during operation of the scroll fluid machine. The high pressure chamber and the low pressure chamber are partitioned by the peripheral portion of the housing member. The peripheral portion of the housing member is mounted on the end face located at the opening side of the first casing. A concave portion for receiving the peripheral portion of the housing member is provided at the inner wall of the second casing. The peripheral portion of the housing member is sandwiched by the wall face of the concave portion and the end face of the first casing.
As described above, there are both a high pressure chamber and a low pressure chamber in a casing, and a concave portion is provided at the inner wall of the second casing to receive the peripheral portion of the housing member. Accordingly, the peripheral portion of the housing member can be made to abut against the wall face of the concave portion by the difference in pressure between the high pressure chamber and the low pressure chamber. As a result, the sealing performance between the peripheral portion of the housing member and the inner wall of the casing can be further improved.
The above casing is a casing of a scroll fluid machine in which the second casing and the first casing are welded. A deformation suppression portion for suppressing deformation of the main body of the housing member according to deformation of the casing caused by the above welding is provided between the casing and the housing member.
As described above, the second casing and the first casing are welded, and a deformation suppression portion for suppressing deformation of the main body of the housing member is provided between the casing and the housing member. A gap provided between the housing member and the casing is an example of the deformation suppression portion. The provision of such a gap allows alleviation of the degree of press to the housing member body from the casing when the casing is deformed inwards by welding. Therefore, the amount of deformation of the housing member body caused by welding can be suppressed to a minimum.
REFERENCES:
patent: 3285504 (1966-11-01), Smith
patent: 4552518 (1985-11-01), Utter
patent: 5382143 (1995-01-0
Hashimoto Kenichi
Hori Kazutaka
Inoue Takeshi
Ueda Shusaku
Burns Doane , Swecker, Mathis LLP
Daikin Industries Ltd.
Vrablik John J.
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