Expansible chamber devices – With assembly or disassembly facilitating means
Reexamination Certificate
1999-07-13
2002-05-07
Lopez, F. Daniel (Department: 3745)
Expansible chamber devices
With assembly or disassembly facilitating means
C092S157000, C074S57900F, C074S587000
Reexamination Certificate
active
06382081
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a relatively compact reciprocating compressor employed in a refrigerator for home use or the like.
BACKGROUND ART
Recently, various improvements for more compactness and facilitation of assembly have been made in reciprocating-compressors and there are users' demands for higher efficiency and lower noises.
Reciprocating compressors of this kind are disclosed in, for example, Japanese Patent Laid-Open Publication No. 4-164174 (1992) and Japanese Patent Publication No. 5-84837 (1993).
In the known reciprocating compressor disclosed in Japanese Patent Publication No. 5-84837 (1993), a compressor body
1
is suspended in a housing
3
by a spring
2
so as to be supported as shown in
FIG. 35. A
crank case
4
includes a mounting portion
4
a
for mounting a motor stator
5
thereon, a bearing portion
4
b
for supporting a crank shaft
7
and a cylinder
4
c
for reciprocating a piston
8
therein, which are formed integrally. A motor rotor
6
is mounted on the crank shaft
7
and the crank shaft
7
includes an eccentric shaft
7
a.
A detailed construction of a connecting rod
10
is shown in FIG.
37
. The connecting rod
10
includes a small end portion
11
and a large end portion
14
. The small end portion
11
includes a cylindrical portion
11
e
having a small hole
11
a
and a rod portion
11
b
having a rectangular cross-sectional shape, which are formed integrally. The rod portion
11
b
extends radially outwardly from the cylindrical portion
11
e
and has a pair of parallel side faces
11
d
and a V-shaped distal end
11
c
. Meanwhile, the large end portion
14
includes a cylindrical portion
14
d
having a large hole
14
a
and a boss
14
b
projecting radially outwardly from the cylindrical portion
14
d
, which are formed integrally. A bore
14
c
for fitting the distal end
11
c
of the rod portion
11
b
of the small end portion
11
thereinto is formed at a central portion of an end face of the boss
14
b.
This known reciprocating compressor is assembled as shown in FIG.
36
. Namely, the small end portion
11
of the connecting rod
10
is coupled with the piston
8
by a piston pin
9
and is fitted into the cylinder
4
c
from an outer side, i.e., a right side in FIG.
36
. Then, a valve plate
12
and a cylinder head
13
are fixed to the cylinder
4
c
. On the other hand, the eccentric shaft
7
a
of the crank shaft
7
is fitted into the large hole
14
a
of the large end portion
14
of the connecting rod
10
. Subsequently, the distal end
11
c
of the rod portion
11
b
of the small end portion
11
is fitted into the bore
14
c
of the boss
14
b
of the large end portion
14
and then, the small end portion
11
and the large end portion
14
are coupled with each other by welding, etc.
Therefore, by coupling the small end portion
11
and the large end portion
14
of the connecting rod
10
as described above, rotation of the crank shaft
7
is converted into reciprocation of the piston
8
so as to compress refrigerant sucked into the cylinder
4
c.
However, in the above described arrangement of the known reciprocating compressor, the small end portion
11
and the large diameter portion
14
of the connecting rod
10
are joined to each other by welding, etc. after fitting of the distal end
11
c
of the rod portion
11
b
of the small end portion
11
into the bore
14
c
of the large diameter portion
14
. Thus, such an inconvenience is incurred that the distal end
11
c
of the rod portion
11
b
and the bore
14
c
of the large end portion
14
should be finished to highly accurate surface roughness.
Furthermore, even if an axis of the large hole
14
a
and an axis of the bore
14
c
deviate from each other even slightly or parallel of the parallel surfaces
11
d
of the rod portion
11
b
to an axis of the small holes
11
a
is out of order even slightly, there is a risk that the axis of the large holes
14
a
and the axis of the small hole
11
a
are subjected to torsion so as to increase rotational load during compression and suction processes upon rotation of the crank shaft
7
, thereby resulting in drop of efficiency.
Meanwhile, in the known reciprocating compressor, there is also a risk that vibrations produced at the piston
8
, the piston pin
9
and the small end portion
11
are directly transmitted to the large end portion
14
, thus resulting in production of abnormal noises between the large end-portion
14
and the eccentric shaft
7
a.
Moreover, in this known reciprocating compressor, since small end portion
11
and the large end portion
14
of the connecting rod
10
are coupled with each other by welding or bonding, the number of its assembly steps increases. In addition, since the small end portion
11
and the large end portion
14
of the connecting rod
10
are fixed to each other immovably by welding or bonding, distortion or torsion of the axes of the small hole
11
a
and the large hole
14
a
is not absorbed by coupling between the small end portion
11
and the large end portion
14
. As a result, machining accuracy of the small hole
11
a
, the large hole
14
a
, the distal end
11
c
and the bore
14
c
should be raised.
DISCLOSURE OF INVENTION
Accordingly, the present invention has for its object to provide, with a view to eliminating the above mentioned disadvantages of prior art, a reciprocating compressor in which its parts can be machined and assembled with high precision easily and rotational load caused by torsion of axes of a large hole and a small hole of a connecting rod is lessened such that not only efficiency of the reciprocating compressor is raised but noises and vibrations of the reciprocating compressor are reduced.
In order to accomplish this object, a reciprocating compressor according to the present invention comprises: a connecting rod which includes a small end portion and a large end portion coupled with each other; wherein the small end portion has a small hole and is coupled with a piston by a piston pin loosely fitted into the small hole, while the large end portion has a large hole such that an eccentric shaft of a crank shaft is loosely fitted into the large hole; wherein the large end portion is formed with a cylindrical bore having an axis passing through a center of the large hole and a fixing hole communicating with the cylindrical bore; wherein the small end portion includes a cylindrical portion having the small hole and a rod portion extending radially outwardly from the cylindrical portion such that the cylindrical portion and the rod portion are formed integrally; wherein a cylindrical retaining portion is provided at a distal end portion of the rod portion of the small end portion; wherein after the cylindrical retaining portion has been loosely fitted into or lightly press fitted into the cylindrical bore, not only the cylindrical retaining portion is retained in the cylindrical bore by inserting a locking pin into the fixing hole while a small torsional degree of freedom about an axis of the rod portion is being imparted to the rod portion but axes of the small hole and the large hole of the connecting rod are maintained on an identical plane.
Therefore, in the reciprocating compressor of the present invention, increase of rotational load upon rotation of the crank shaft during compression and suction processes and drop of efficiency due to this increase of rotational load can be obviated. Furthermore, machining properties of its parts can be upgraded and production and assembly of the reciprocating compressor can be facilitated.
REFERENCES:
patent: 1741621 (1929-12-01), Godfrey
patent: 2005107 (1935-06-01), Phillips et al.
patent: 2445020 (1948-07-01), Charles
patent: 2675759 (1954-04-01), Yarger
patent: 3276677 (1966-10-01), Trask
patent: 4930405 (1990-06-01), Lilie
patent: 5848566 (1998-12-01), Walsh
patent: 31 11 947 (1982-10-01), None
patent: 44 18 112 (1995-12-01), None
patent: 0 592 812 (1994-04-01), None
patent: 2 211 272 (1989-06-01), None
patent: 4-164174 (1992-06-01), None
patent: 5-84837 (1993-12-
Kita Ichiro
Oda Masataka
Tanaka Yasuhiko
Umeoka Ikutomo
Lopez F. Daniel
Matsushita Refrigeration Company
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Reciprocating compressor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reciprocating compressor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reciprocating compressor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2844683