Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
1998-09-23
2001-03-20
Yuen, Henry C. (Department: 3747)
Pumps
Motor driven
Electric or magnetic motor
C415S182100
Reexamination Certificate
active
06203290
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a closed-type electrically-driven compressor, and more particularly to a closed-type electrically-driven compressor employing a high pressure chamber system used for refrigerators and air conditioners.
2. Description of the Prior Art
A closed-type electrically-driven compressor employing a conventional high pressure chamber system will be described below with reference to
FIGS. 4
to
6
.
FIG. 4
is a cross sectional view showing a structure of a closed-type electrically-driven compressor of the prior art,
FIG. 5
is a cross sectional view of a main portion of a cylindrical body and a cover body in a general closed-type electrically-driven compressor popular of the prior art and
FIG. 6
is a cross sectional view showing an essential part of the prior closed-type electrically-driven compressor with its cover body deformed due to an internal pressure.
The closed-type electrically-driven compressor shown in
FIG. 4
is structured such that a compressing mechanism portion
10
and an electric motor portion
20
driving the compressing mechanism portion are received within a cylindrical body
30
, which constitutes a main body of a closed container, a refrigerant sucked from a refrigerant suction pipe
40
is compressed in the compressing mechanism portion
10
and then discharged into the cylindrical body
30
(the closed container) from a refrigerant discharge port
11
provided in the compressing mechanism portion
10
to be filled in the cylindrical body
30
and then discharged from a discharge pipe
41
. The closed container is constructed (a high pressure chamber system) such that internal pressures are caused by the refrigerant to act thereon in operation.
The cylindrical body
30
shown in
FIG. 4
is substantially formed in a cylindrical shape, and is provided with a cover body
31
which sealing the cylindrical body
30
. The cover body
31
is formed by press work of a steel sheet. Further, a terminal
50
is fitted in a hole formed in the cover body
31
to be welded to the cover body
31
. Since the refrigerant exerts internal pressures on the cover body
31
during operation as mentioned above, it is necessary to ensure a pressure resisting strength against a high pressure in operation. As a countermeasure thereof, it is generally known as an ideal configuration to form the cover body substantially in a spherical shape.
However, such spherical-shaped cover body increases a length of the closed container of the compressor to increase a space in the refrigerant equipment, into which the compressor is mounted. Further, in the case of mounting on the cover body the terminal
50
for supplying electricity to the electric motor portion
20
, which drives the compressing mechanism portion
10
, and the pipes
40
and
41
for circulating the refrigerant and the like, there are caused problems with espect to weldability, assembling quality, formability of the cover body itself and the like. Then, as shown in
FIG. 5
, the cover body
31
employs a substantially flat configuration to improve productivity.
A structure of the closed container having the substantially flat cover body and shown in
FIG. 5
will be described hereinbelow.
The reference numeral
30
denotes a cylindrical body which constitutes a main body of the closed container, and the compressing mechanism portion
10
and the electric motor portion
20
are received within the cylindrical body
30
, which is not shown in the drawing. The reference numeral
31
denotes a cover body, which is fixed to the cylindrical body
30
through a welded portion
32
to form a container of the closed-type compressor. The reference numeral
50
denotes a terminal, which is fixed to a hole formed on an upper surface of the cover body
31
through a welded portion
51
.
Further, a terminal pin
52
for supplying electricity to the electric motor is provided inside and outside the terminal
50
. The reference numeral
40
denotes a refrigerant suction pipe, which is fixed to the cover body
31
of the cylindrical body
30
through a welded portion
41
. The reference numeral
60
denotes a pin for securing of a cover covering the terminal
50
, which is fixed to the cover body
31
of the cylindrical body
30
through a welded portion
61
.
Incidentally, Japanese Utility Model Publication Nos. 64-1495 and 3-57318 disclose a prior art with respect to the container of prior closed-type compressors.
Such prior closed-type compressors present the following problems in the structure of their cover.
In recent years, it has been necessary to employ an alternative refrigerant in refrigeration and air conditioning equipments for the purpose of preventing an ozone layer from being broken, and the substitutive refrigerant includes a refrigerant, typified by refrigerant R-410A, which involves a pressure about 1.5 times that of the conventional refrigerant under the same temperature condition.
When such refrigerant involving a high pressure is used to operate the compressor having the conventional closed container as shown in
FIG. 5
, internal pressures acting on the cover body
31
tend to deform a substantially flat portion into a spherical shape as shown in FIG.
6
. Accordingly, since a central portion of the cover body
31
is tensioned in a radial direction, it is made thin in thickness. Further, since a force tending to strip off the welded portion
51
between the cover body
31
and the terminal
50
or the welded portion
41
between the cover body
31
and the refrigerant suction pipe
40
is increased more than the conventional manner, problems of leakage of the refrigerant are liable to occur.
Then, increasing a thickness of the cover body may be adopted as means for solving the problem, investigation reveals that the thickness of the cover body
31
should be increased to about 2.5 times the conventional thickness in order to stand an increase of the pressure amounting to about 1.5 times that with the conventional refrigerant. Therefore, there are caused problems that the cover body can not be easily formed by press work of a steel sheet and it is increased in weight.
SUMMARY OF THE INVENTION
The present invention solves the problems the in prior art mentioned above, and has its object to provide a closed-type electrically-driven compressor using an alternative refrigerant, typified by a refrigerant R-410A, in which an increase in a thickness of a cover body is limited as much as possible, a pressure resisting quality is ensured, and an assembling quality such as weldability between the cover body and a terminal and between the cover body and a refrigerant circulating pipe is improved.
In order to achieve the object mentioned above, in an aspect, the present invention provides a closed-type electrically-driven compressor comprising a compressing mechanism portion and an electric motor portion driving the compressing mechanism portion within a closed container, which is formed to be substantially cylindrical, and a terminal fitted into a hole formed in a cover body of the closed container and welded to the cover body, and wherein a central portion and vicinities of the cover body on the closed container are formed in either of concave and convex shapes. In the course of development of the invention, a center of a cover body of a closed container, more specifically, a portion from a terminal toward the center of the cover body, on which a drawn portion (equivalent to a rib) was tested, but an effect of relaxing stress concentration was of little avail. In this respect, it was confirmed that when such drawn portion was extended from the center of the cover body toward vicinities thereof, some effect of relaxing stress concentration was of little avail.
Further, in order to achieve the object mentioned above, in another aspect, the present invention provides a closed-type electrically-driven compressor comprising a compressing mechanism portion and an electric motor portion driving the compressing mechanism portion within a closed container,
Sekiguchi Koichi
Shimada Atsushi
Tadokoro Tetsuya
Tamura Kazumi
Terai Toshiyuki
Antonelli Terry Stout & Kraus LLP
Castro Arnold
Hitachi , Ltd.
Yuen Henry C.
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