U.S. patent application number 09/297922 was filed with the patent office on 2002-01-03 for reciprocating compressor.
Invention is credited to KITA, ICHIRO, ODA, MASATAKA, TANAKA, YASUHIKO, UMEOKA, IKUTOMO.
Application Number | 20020000160 09/297922 |
Document ID | / |
Family ID | 27454055 |
Filed Date | 2002-01-03 |
United States Patent
Application |
20020000160 |
Kind Code |
A1 |
TANAKA, YASUHIKO ; et
al. |
January 3, 2002 |
RECIPROCATING COMPRESSOR
Abstract
A reciprocating compressor (K1-K3) comprising: a connecting rod
(21) in which a small end portion (22) having a small hole (22a)
and a large end portion (25) having a large hole (25a) are coupled
with each other; wherein the small end portion (22) is coupled with
a piston (24) by a piston pin (23) loosely fitted into the small
hole (22a), while an eccentric shaft (7a) of a crank shaft (7) is
loosely fitted into the large hole (25a); wherein the large end
portion (25) is formed with a cylindrical bore (25b) having an axis
passing through a center of the large hole (25a) and a fixing hole
(25c, 28, 30) communicating with the cylindrical bore (25b);
wherein after a cylindrical distal end portion (22c) of a rod
portion (22b) of the small end portion (22) has been loosely fitted
into or lightly press fitted into the cylindrical bore (25b), not
only the cylindrical distal end portion (22c) is fixed in the
cylindrical bore (25b) by inserting a locking pin (26) into the
fixing hole (25c, 28, 30) while a small torsional degree of freedom
about an axis of the rod portion (22b) is being imparted to the rod
portion (22b) but axes of the small hole (22a) and the large hole
(25a) of the connecting rod (21) are disposed so as to be
maintained on an identical plane.
Inventors: |
TANAKA, YASUHIKO; (NARA,
JP) ; UMEOKA, IKUTOMO; (NARA, JP) ; KITA,
ICHIRO; (SHIKI-GUN, JP) ; ODA, MASATAKA;
(OSAKA, JP) |
Correspondence
Address: |
WENDEROTH LIND & PONACK
2033 K STREET NW
SUITE 800
WASHINGTON
DC
20006
|
Family ID: |
27454055 |
Appl. No.: |
09/297922 |
Filed: |
July 13, 1999 |
PCT Filed: |
November 25, 1997 |
PCT NO: |
PCT/JP97/04275 |
Current U.S.
Class: |
92/140 |
Current CPC
Class: |
F16C 7/02 20130101; F16B
21/12 20130101; Y10T 74/2152 20150115; F04B 39/14 20130101; F04B
39/0022 20130101; F16B 21/16 20130101; Y10T 74/2162 20150115 |
Class at
Publication: |
92/140 |
International
Class: |
F01B 009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 26, 1996 |
JP |
P8-314575 |
Jan 14, 1997 |
JP |
P9-4296 |
Jan 27, 1997 |
JP |
P9-12166 |
Sep 24, 1997 |
JP |
P9-258140 |
Claims
1. A reciprocating compressor (K1-K3) comprising: a connecting rod
(21) which includes a small end portion (22) and a large end
portion (25) coupled with each other; wherein the small end portion
(22) has a small hole (22a) and is coupled with a piston (24) by a
piston pin (23) loosely fitted into the small hole (22a), while the
large end portion (25) has a large hole (25a) such that an
eccentric shaft (7a) of a crank shaft (7) is loosely fitted into
the large hole (25a); wherein the large end portion (25) is formed
with a cylindrical bore (25b) having an axis passing through a
center of the large hole (25a) and a fixing hole (25c, 28, 30)
communicating with the cylindrical bore (25b); wherein the small
end portion (22) includes a cylindrical portion (22e) having the
small hole (22a) and a rod portion (22b) extending radially
outwardly from the cylindrical portion (22e) such that the
cylindrical portion (22e) and the rod portion (22b) are formed
integrally; wherein a cylindrical retaining portion (22c) is
provided at a distal end portion of the rod portion (22b) of the
small end portion (22); wherein after the cylindrical retaining
portion (22c) has been loosely fitted into or lightly press fitted
into the cylindrical bore (25b), not only the cylindrical retaining
portion (22c) is fixed in the cylindrical bore (25b) by inserting a
locking pin (26) into the fixing hole (25c, 28, 30) while a small
torsional degree of freedom about an axis of the rod portion (22b)
is being imparted to the rod portion (22b) but axes of the small
hole (22a) and the large hole (25a) of the connecting rod (21) are
disposed so as to be maintained on an identical plane.
2. A reciprocating compressor (K3) as claimed in claim 1, wherein a
key groove (29) is formed on a side surface of the cylindrical
retaining portion (22c); wherein when the cylindrical retaining
portion (22c) of the rod portion (22) is loosely fitted into or
lightly press fitted into the cylindrical bore (25b) and the
locking pin (26) is inserted into the fixing hole (30) so as to
extend through the key groove (29), the cylindrical retaining
portion (22c) is fixed in the cylindrical bore (25b) while the
small torsional degree of freedom about the axis of the rod portion
(22b) is being imparted to the rod portion (22b).
3. A reciprocating compressor (K4-K6) comprising: a connecting rod
(40) which includes a small end portion (50) and a large end
portion (52); wherein the small end portion (50) has a small hole
(51) and is coupled with a piston (24) at the small hole (51) by a
piston pin (23), while the large end portion (52) has a large hole
(53) and is coupled with an eccentric shaft (7a) of a crank shaft
(7) at the large hole (53); wherein the large end portion (52)
includes a boss (56) having a cylindrical bore (54) and a fixing
hole (55) communicating with the cylindrical bore (54) and the
cylindrical bore (54) has a hemispherical or substantially conical
bottom (63); wherein the cylindrical bore (54) extends from an end
face (57) of the boss (56) towards a center of the large hole (53)
to such a depth as not to open to the large hole (53); wherein the
small end portion (50) includes a cylindrical rod portion (58)
extending radially outwardly from the small hole (51) and the rod
portion (58) is provided, at its one end portion, with a retaining
hole (59) and a retaining portion (60) having a hemispherical or
substantially conical distal end (61); wherein when the retaining
portion (60) is loosely fitted into or lightly press fitted into
the cylindrical bore (54) of the boss (56) and a locking pin (65)
is inserted through the fixing hole (55) and the retaining hole
(59), the retaining portion (60) is fixed in the cylindrical bore
(54) and axes of the small hole (51) of the small end portion (50)
and the large hole (53) of the large end portion (52) are disposed
so as to be maintained on an identical plane.
4. A reciprocating compressor (K6) as claimed in claim 3, wherein
an oil hole (79) for communicating a tip (64) of the bottom (63) of
the cylindrical bore (54) and the large hole (53) with each other
is formed on the large end portion (52) and is communicated with an
oil groove (78) of the eccentric shaft (7a) of the crank shaft
(7).
5. A reciprocating compressor (K10) comprising: a connecting rod
(95) which includes a small end portion (100) and a large end
portion (102); wherein the small end portion (100) has a small hole
(101) and is coupled with a piston (24) at the small hole (101) by
a piston pin (23), while the large end portion (102) has a large
hole (103) and is coupled with an eccentric shaft (7a) of a crank
shaft (7) at the large hole (103); wherein a dovetail groove (105)
is formed on one (102) of the small end portion (100) and the large
end portion (102) and a dovetail (104) is formed on the other (100)
of the small end portion (100) and the large end portion (102); and
a substantially U-shaped clamp (107) which is engaged with the
dovetail (104) so as to limit vertical movement of the large end
portion (102) and the small end portion (100).
6. A reciprocating compressor (K10) comprising: a connecting rod
(95) which includes a small end portion (100) and a large end
portion (102); wherein the small end portion (100) has a small hole
(101) and is coupled with a piston (24) at the small hole (101) by
a piston pin (23), while the large end portion (102) has a large
hole (103) and is coupled with an eccentric shaft (7a) of a crank
shaft (7) at the large hole (103); wherein a dovetail groove (105)
is formed on one (102) of the small end portion (100) and the large
end portion (102) and a dovetail (104) is formed on the other (100)
of the small end portion (100) and the large end portion (102);
wherein an engageable slot (109) and an engageable recess (108)
are, respectively, formed on the one (102) of the small end portion
(100) and the large end portion (102) and the dovetail (104); and a
substantially U-shaped clamp (107) which is fitted into the
engageable slot (109) and the engageable recess (108).
7. A reciprocating compressor (K10) as claimed in claim 6, wherein
depths of the engageable slot (109) and the engageable recess (108)
are determined such that the engageable slot (109) and the
engageable recess (108) form a step (110) when the small end
portion (100) and the large end portion (102) have been set in
place; wherein the clamp (107) is retained by the step (110) so as
to be prevented from being detached from the one (102) of the small
end portion (100) and the large end portion (102).
8. A reciprocating compressor (K11) comprising: a connecting rod
(95) which includes a small end portion (100) and a large end
portion (102); wherein the small end portion (100) has a small hole
(101) and is coupled with a piston (24) at the small hole (101) by
a piston pin (23), while the large end portion (102) has a large
hole (103) and is coupled with an eccentric shaft (7a) of a crank
shaft (7) at the large hole (103); wherein a dovetail groove (105)
is formed on one (102) of the small end portion (100) and the large
end portion (102) and a dovetail (104) is formed on the other (100)
of the small end portion (100) and the large end portion (102); and
a press fitting pin (114) which is press fitted into a pin hole
(115) formed at a boundary between the dovetail groove (105) and
the dovetail (104) so as to secure the small end portion (100) and
the large end portion (102) to each other.
9. A reciprocating compressor (K12) comprising: a connecting rod
(120) which includes a small end portion (100) and a large end
portion (102); wherein the small end portion (100) has a small hole
(101) and is coupled with a piston (24) at the small hole (101) by
a piston pin (23), while the large end portion (102) has a large
hole (103) and is coupled with an eccentric shaft (7a) of a crank
shaft (7) at the large hole (103); wherein a dovetail groove (105)
is formed on one (102) of the small end portion (100) and the large
end portion (102) and a dovetail (104) is formed on the other (100)
of the small end portion (100) and the large end portion (102);
wherein two retaining faces (124) acting as positioning faces for
assembly are formed at one vertex portion of the dovetail groove
(105) such that only two neighboring sides of the dovetail (104)
are brought into engagement with the retaining faces (124).
10. A reciprocating compressor (K13) comprising: a connecting rod
(120) which includes a small end portion (100) and a large end
portion (102); wherein the small end portion (100) has a small hole
(101) and is coupled with a piston (24) at the small hole (101) by
a piston pin (23), while the large end portion (102) has a large
hole (103) and is coupled with an eccentric shaft (7a) of a crank
shaft (7) at the large hole (103); wherein a dovetail groove (105)
is formed on one (102) of the small end portion (100) and the large
end portion (102) and a dovetail (104) is formed on the other (100)
of the small end portion (100) and the large end portion (102);
wherein a contact face (126) acting as a positioning face for
assembly is formed on the dovetail (104) so as to be brought into
engagement with only two neighboring sides of the dovetail groove
(105).
Description
TECHNICAL FIELD
[0001] The present invention relates to a relatively compact
reciprocating compressor employed in a refrigerator for home use or
the like.
BACKGROUND ART
[0002] 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.
[0003] 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).
[0004] 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 4a for
mounting a motor stator 5 thereon, a bearing portion 4b for
supporting a crank shaft 7 and a cylinder 4c 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 7a.
[0005] 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 11e having a small hole 11a and a rod portion
11b having a rectangular cross-sectional shape, which are formed
integrally. The rod portion 11b extends radially outwardly from the
cylindrical portion 11e and has a pair of parallel side faces 11d
and a V-shaped distal end 11c. Meanwhile, the large end portion 14
includes a cylindrical portion 14d having a large hole 14a and a
boss 14b projecting radially outwardly from the cylindrical portion
14d, which are formed integrally. A bore 14c for fitting the distal
end 11c of the rod portion 11b of the small end portion 11
thereinto is formed at a central portion of an end face of the boss
14b.
[0006] 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 4c 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 4c. On the other hand, the eccentric shaft 7a of the crank
shaft 7 is fitted into the large hole 14a of the large end portion
14 of the connecting rod 10. Subsequently, the distal end 11c of
the rod portion 11b of the small end portion 11 is fitted into the
bore 14c of the boss 14b 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.
[0007] 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.
[0008] 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 11c of the
rod portion 11b of the small end portion 11 into the bore 14c of
the large diameter portion 14. Thus, such an inconvenience is
incurred that the distal end 11c of the rod portion 11b and the
bore 14c of the large end portion 14 should be finished to highly
is accurate surface roughness.
[0009] Furthermore, even if an axis of the large hole 14a and an
axis of the bore 14c deviate from each other even slightly or
parallel of the parallel surfaces 11b of the rod portion 11b to an
axis of the small hole 11a is out of order even slightly, there is
a risk that the axis of the large hole 14a and the axis of the
small hole 11a 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.
[0010] 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
7a.
[0011] Moreover, in this known reciprocating compressor, since the
small end portion hand 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 11a and the
large hole 14a 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 11a, the large hole 14a, the distal end
11c and the bore 14c should be raised.
DISCLOSURE OF INVENTION
[0012] 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.
[0013] 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.
[0014] 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.
[0015] This object and features of the present invention will
become clear from the following description taken in conjunction
with the preferred embodiments thereof with reference to the
accompanying drawings throughout which like parts are designated by
like reference numerals.
BRIEF DESCRIPTION OF DRAWINGS
[0016] FIG. 1 is a partly sectional fragmentary view of a
reciprocating compressor according to a first embodiment of the
present invention.
[0017] FIG. 2 is a partly sectional exploded view of the
reciprocating compressor of FIG. 1, particularly showing a
connecting rod and a piston.
[0018] FIG. 3 is a top plan view showing the connecting rod of FIG.
2 prior to its assembly.
[0019] FIG. 4 is a partly sectional front elevational view showing
the connecting rod of FIG. 2 during its assembly.
[0020] FIG. 5 is an end view as observed in the direction of the
arrow V in FIG. 4, showing the connecting rod of FIG. 2 during
drive of the reciprocating compressor of FIG. 1.
[0021] FIG. 6 is a top plan view showing a connecting rod of a
reciprocating compressor according to a second embodiment of the
present invention prior to its assembly.
[0022] FIG. 7 is a partly sectional front elevational view showing
the connecting rod of FIG. 6 during its assembly.
[0023] FIG. 8 is a top plan view showing a connecting rod of a
reciprocating compressor according to a third embodiment of the
present invention prior to its assembly.
[0024] FIG. 9 is a partly sectional front elevational view showing
the connecting rod of FIG. 8 during its assembly.
[0025] FIG. 10 is a fragmentary sectional view of a reciprocating
compressor according to a fourth embodiment of the present
invention.
[0026] FIG. 11 is a partly sectional exploded view of the
reciprocating compressor of FIG. 10, particularly showing a
connecting rod and a piston.
[0027] FIG. 12 is a top plan view showing the connecting rod of
FIG. 11 prior to its assembly.
[0028] FIG. 13 is a partly sectional front elevational view showing
the connecting rod of FIG. 11 during its assembly.
[0029] FIG. 14 is a top plan view showing a connecting rod of a
reciprocating compressor according to a fifth embodiment of the
present invention prior to its assembly.
[0030] FIG. 15 is an end view as observed in the direction of the
arrow XV in FIG. 14, particularly showing a large end portion of
the connecting rod of FIG. 14.
[0031] FIG. 16 is a partly sectional front elevational view showing
the connecting rod of FIG. 14 during its assembly.
[0032] FIG. 17 is a partly sectional fragmentary view of a
reciprocating compressor according to a sixth embodiment of the
present invention, particularly showing a connecting rod and an
eccentric shaft during a suction process.
[0033] FIG. 18 is a view similar to FIG. 17, particularly showing
the connecting rod and the eccentric shaft during a compression
process.
[0034] FIG. 19 is a top plan view showing a connecting rod of a
reciprocating compressor according to a seventh embodiment of the
present invention prior to its assembly.
[0035] FIG. 20 is a partly sectional front elevational view showing
the connecting rod of FIG. 19 during its assembly.
[0036] FIG. 21 is a top plan view showing a connecting rod of a
reciprocating compressor according to an eighth embodiment of the
present invention prior to its assembly.
[0037] FIG. 22 is a partly sectional front elevational view showing
the connecting rod of FIG. 21 during its assembly.
[0038] FIG. 23 is a top plan view showing a connecting rod of a
reciprocating compressor according to a ninth embodiment of the
present invention prior to its assembly.
[0039] FIG. 24 is a partly sectional front elevational view showing
the connecting rod of FIG. 23 during its assembly.
[0040] FIG. 25 is a partly sectional fragmentary view of a
reciprocating compressor according to a tenth embodiment of the
present invention.
[0041] FIG. 26 is a fragmentary exploded view of the reciprocating
compressor of FIG. 25.
[0042] FIG. 27 is a top plan view of a connecting rod of the
reciprocating compressor of FIG. 25.
[0043] FIG. 28 is a sectional view taken along the line
XXVIII-XXVIII in FIG. 27.
[0044] FIG. 29 is a top plan view of a connecting rod of a
reciprocating compressor according to an eleventh embodiment of the
present invention.
[0045] FIG. 30 is fragmentary exploded view of a reciprocating
compressor according to a twelfth embodiment of the present
invention.
[0046] FIG. 31 is a perspective view of an overturned large end
portion of a connecting rod of the reciprocating compressor of FIG.
30.
[0047] FIG. 32 is a side elevational view of the large end portion
of FIG. 31.
[0048] FIG. 33 is a perspective view indicative of coupling between
the large end portion and a small end portion of the connecting rod
of the reciprocating compressor of FIG. 30.
[0049] FIG. 34 is a fragmentary perspective view of a small end
portion of a connecting rod of a reciprocating compressor according
to a thirteenth embodiment of the present invention.
[0050] FIG. 35 is a partly sectional fragmentary view of a prior
art reciprocating compressor.
[0051] FIG. 36 is a partly sectional exploded view of the prior art
reciprocating compressor of FIG. 35, particularly showing a
connecting rod and a piston.
[0052] FIG. 37 is an exploded top plan view of the connecting rod
of FIG. 36.
BEST MODE FOR CARRYING OUT THE INVENTION
[0053] Hereinafter, preferred embodiments of the present invention
are described with reference to the attached drawings. FIG. 1 shows
a reciprocating compressor K1 according to a first embodiment of
the present invention. In the reciprocating compressor K1, a
compressor body 1 is suspended in a housing 3 so as to be
supported. A crank case 4 includes a mounting portion 4a for
mounting a motor stator 5 thereon, a bearing portion 4b for
supporting a crank shaft 7 and a cylinder 4c for reciprocating a
piston 24 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 7a. A valve plate 12 and a cylinder head 13 are
secured to the cylinder 4c.
[0054] The reciprocating compressor K1 further includes a
connecting rod 21. The connecting rod 21 includes a small end
portion 22 and a large end portion 25. The small end portion 22 is
coupled with the piston 24 by a piston pin 23 loosely fitted into a
small hole 22a of the small end portion 22, while the eccentric
shaft 7a of the crank shaft 7 is loosely fitted into a large hole
25a of the large end portion 25.
[0055] FIG. 2 shows an assembly method of the reciprocating
compressor K1 in which the piston 24 assembled with the small end
portion 22 is inserted into the cylinder 4c from one side of the
cylinder 4c remote from the crank shaft 7 and the eccentric shaft
7a of the crank shaft 7 is fitted into the large hole 25a of the
large end portion 25 by lowering the large end portion 25
downwardly from above the eccentric shaft 7a.
[0056] A cylindrical bore 25b is formed on an end face of the large
end portion 25 such that an axis of the cylindrical bore 25b passes
through a center of the large hole 25a. A fixing hole 25c is formed
on the large end portion 25 so as to pierce through an upper wall
of the cylindrical bore 25b such that the fixing hole 25c opens to
the cylindrical bore 25c. Meanwhile, the small end portion 22
includes a cylindrical portion 22e having the small hole 22a and a
cylindrical rod portion 22b extending radially outwardly from the
cylindrical portion 22e, which are formed integrally. A retaining
hole 22d is formed, as a blind hole, at a distal end portion of the
rod portion 22b such that the distal end portion of the rod portion
22b acts as a retaining portion 22c.
[0057] In FIGS. 3 and 4, after the retaining portion 22c of the rod
portion 22b of the small end portion 22 has been inserted into the
cylindrical bore 25b of the large end portion 25, a locking pin 26
is inserted from the fixing hole 25c into the retaining hole 22d of
the small end portion 22 so as to couple the small end portion 22
and the large end portion 25 of the connecting rod 21 with each
other.
[0058] In the above described arrangement of the reciprocating
compressor K1, since both of the bore 25b of the large end portion
25 and the retaining portion 22c of the small end portion 22, which
act as a coupling means between the large end portion 25 and the
small end portion 22, are cylindrical, the bore 25b and the
retaining portion 22c can be easily machined with high dimensional
precision.
[0059] FIG. 5 shows a view in the direction of the arrow V in FIG.
4. In FIG. 5, a line C represents an axis of the large hole 25a,
while lines D and E represent an axis of the small hole 22a. When
the line C has a length of 100 mm, a deflection from the line C to
the line D or E is mere 100 microns or so. As described above, both
of the bore 25b and the retaining portion 22c, which acts as the
coupling means between the large end portion 25 and the small end
portion 22, are cylindrical. Thus, before the locking pin 26 is
inserted into the retaining hole 22d, the axis of the small hole
22a can be deflected about an axis of the rod portion 22b from the
line D to the line E or from the line E to the line D. However,
after the locking pin 26 has been inserted into the retaining hole
22d, the axis of the small hole 22a is fixed by elastic force of
the locking pin 26 so as to substantially coincide with the line
C.
[0060] Therefore, if the axes of the small hole 22a and the large
hole 25a do not coincide with each other completely at the line C
due to their distortion during compression and suction processes of
a reciprocating compressor, abnormal contact between the small hole
22a and the piston pin 23 or between the large hole 25a and the
eccentric shaft 7a happens and thus, rotational load increases,
thereby resulting in drop of efficiency.
[0061] On the contrary, in the reciprocating compressor K1, since
the rod portion 22b has slight torsional degree of freedom about
the axis of the rod portion 22b and the locking pin 25 has a
self-compensating function of absorbing the minute deflection of
the axis of the small hole 22a between the lines D and E so as to
make the axes of the small hole 22a and the large hole 25a
coincident with each other stably, increase of rotational load
caused by torsion of the axes of the small hole 22a and the large
hole 25a and drop of efficiency due to this increase of rotational
load can be prevented.
[0062] FIGS. 6 and 7 show the connecting rod 21 employed in a
reciprocating compressor K2 according to a second embodiment of the
present invention. A retaining through-hole 27 is formed at the
retaining portion 22c in parallel with the small hole 22a.
Meanwhile, a fixing through-hole 28 is formed on the large end
portion 25 so as to pierce through upper and lower walls of the
cylindrical bore 25b via the retaining through-hole 27 of the small
end portion 22 when the retaining portion 22c of the small end
portion 22 has been inserted into the cylindrical bore 25b of the
large end portion 25. By inserting the locking pin 26 through the
fixing through-hole 28 of the large end portion 25 via the
retaining through-hole 27 of the small end portion 22, the
connecting rod 21 is assembled. Since other constructions of the
reciprocating compressor K2 are similar to those of the
reciprocating compressor K1, the description is abbreviated for the
sake of brevity.
[0063] Therefore, when the small end portion 22 and the large end
portion 25 are coupled with each other during assembly of the
reciprocating compressor K2, the retaining through-hole 27 of the
small end portion 22 and the fixing through-hole 28 of the large
end portion 25 form a through-hole, so that the locking pin 26 can
be inserted into the fixing through-hole 28 from either one of
opposite faces of the large end portion 25. As a result, not only
the retaining through-hole 27 and the fixing through-hole 28 can be
easily machined with high dimensional accuracy but assembly of the
reciprocating compressor K2 is further facilitated. Meanwhile,
increase of rotational load caused by torsion of the axes of the
small hole 22a and the large hole 25a and drop of efficiency due to
this increase of rotational load can be prevented.
[0064] FIGS. 8 and 9 show the connecting rod 21 employed in a
reciprocating compressor K3 according to a third embodiment of the
present invention. A key groove 29 is formed on a side surface of
the retaining portion 22c of the rod portion 22b of the small end
portion 22 in parallel with the small hole 22a. Meanwhile, a fixing
through-hole 30 is formed on the large end portion 25 so as to
pierce through the large end portion 25 at a periphery of the
cylindrical bore 25b such that the fixing through-hole 30 confronts
the key groove 29 when the retaining portion 22c of the small end
portion 22 has been inserted into the cylindrical bore 25b. By
inserting the locking pin 26 through the fixing through-hole 30 of
the large end portion 25 via the key groove 29 of the small end
portion 22, the connecting rod 21 is assembled. Since other
constructions of the reciprocating compressor K3 are similar to
those of the reciprocating compressor K1, the description is
abbreviated for the sake of brevity.
[0065] Therefore, when the small end portion 22 and the large end
portion 25 are coupled with each other during assembly of the
reciprocating compressor K3, the key groove 29 of the small end
portion 22 and the fixing through-hole 30 of the large end portion
25 form a through-hole, so that the locking pin 26 can be inserted
into the fixing through-hole 30 from either one of opposite faces
of the large end portion 25 and thus, assembly of the reciprocating
compressor K3 is facilitated. In addition, since the key groove 29
can be machined more easily than the retaining hole 22d of the
reciprocating compressor K1 and the retaining through-hole 27 of
the reciprocating compressor K2, machining of -the reciprocating
compressor K3 is further facilitated. It is needless to say that
increase of rotational load caused by torsion of the axes of the
small hole 22a and the large hole 25a and drop of efficiency due to
this increase of rotational load can be prevented.
[0066] As is clear from the foregoing description, the
reciprocating compressors K1 to K3 include the large end portion
formed with the cylindrical bore having the axis passing through
the center of the large hole and the fixing hole communicating with
the cylindrical bore; wherein the small end portion includes the
cylindrical portion having the small hole and the rod portion
extending radially outwardly from the cylindrical portion such that
the cylindrical portion and the rod portion are formed integrally;
wherein the cylindrical retaining portion is provided at the 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 the locking pin into the fixing hole while a
small torsional degree of freedom about the axis of the rod portion
is being imparted to the rod portion but the axes of the small hole
and the large hole of the connecting rod are disposed so as to be
maintained on an identical plane.
[0067] Therefore, in the reciprocating compressors K1 to K3,
increase of rotational load caused by torsion of the axes of the
small hole and the large hole and drop of efficiency due to this
increase of rotational load can be prevented. Meanwhile, both of
the bore of the large end portion and the retaining portion of the
small end portion, which act as the coupling means between the
large end portion and the small end portion, are cylindrical, the
bore and the retaining portion can be easily machined with high
dimensional precision and production and assembly of the
reciprocating compressors K1 to K3
[0068] Meanwhile, in the reciprocating compressor K2, after the
retaining portion of the small end portion has been fitted into the
cylindrical bore of the large end portion, the locking pin is
inserted through the fixing hole of the cylindrical bore via the
retaining hole of the retaining portion of the rod portion.
Therefore, since the locking pin can be inserted into the fixing
hole from either one of the opposite faces of the large end
portion, the reciprocating compressor K2 can be assembled more
easily.
[0069] Furthermore, in the reciprocating compressor K3, the key
groove is formed on the side surface of the cylindrical retaining
portion of the small end portion and the fixing hole is formed on
the large end portion at the periphery of the cylindrical bore so
as to confront the key groove when the cylindrical retaining
portion of the small end portion has been inserted into the
cylindrical bore of the large end portion such that the small end
portion and the large end portion are coupled with each other by
inserting the locking pin through the fixing through-hole via the
key groove. The key groove of the reciprocating compressor K3 can
be machined more easily than the retaining hole of the
reciprocating compressors K1 and K2.
[0070] FIG. 10 shows a reciprocating compressor K4 according to a
fourth embodiment of the present invention. In the reciprocating
compressor K4, a connecting rod 40 includes a small end portion 50
having a small hole 51 and a large end portion 52 having a large
hole 53. One end of the connecting rod 40 is coupled with the
piston 24 by the piston pin 23 loosely fitted into the small hole
51 of the small end portion 50, while the other end of the
connecting rod 40 is coupled with the eccentric shaft 7a by loosely
fitting the eccentric shaft 7a into the large hole 53 of the large
end portion 52.
[0071] In FIG. 11, the piston 24, the piston pin 23 and the small
end portion 50 is inserted into the cylinder 4c from one side of
the cylinder 4c remote from the crank shaft 7, while the eccentric
shaft 7a is inserted into the large hole 53 of the large end
portion 52 by lowering the large end portion 52 from above the
eccentric shaft 7a.
[0072] As shown in FIG. 12, the large end portion 52 of the
connecting rod 40 has a boss 56 and a cylindrical bore 54 is formed
on an end face 57 of the boss 56 such that an axis of the
cylindrical bore 54 passes through an axis of the large hole 53. A
fixing through-hole 55 is formed on the large end portion 52 so as
to pierce through the large end portion 52 via the cylindrical bore
54. The cylindrical bore 54 extends orthogonally to the axis of the
large hole 53 to such a depth as not to open to the large hole 53.
The small end portion 50 includes a rod portion 58 extending
radially outwardly from the small hole 51 at right angles to an
axis of the small hole 51. A retaining portion 60 is provided at a
distal end portion of the rod portion 58 and a retaining
through-hole 59 is formed at the retaining portion 60.
[0073] In FIGS. 12 and 13, a hemispherical or substantially conical
retaining projection 61 having a rounded retaining tip 62 is
provided at a distal end of the retaining portion 60. A
hemispherical or substantially conical fixing slot 63 having a tip
64 is formed at a distal end of the cylindrical bore 54. After the
retaining portion 60 of the small end portion 50 has been inserted
into the cylindrical bore 54 of the large end portion 52, a locking
pin 65 is inserted through the fixing through-hole 55 via the
retaining through-hole 59 and thus, the small end portion 50 and
the large end portion 52 of the connecting rod 40 are securely
coupled with each other.
[0074] Hereinafter, operation of the reciprocating compressor K4 of
the above described arrangement is described. Both of the
cylindrical bore 54 of the large end portion 52 and the retaining
portion 60 of the small end portion 50, which act as a coupling
means between the large end portion 52 and the small end portion
50, are cylindrical and therefore, can be easily machined with high
dimensional accuracy. When the retaining portion 60 is loosely
fitted into or lightly press fitted into the cylindrical bore 54,
the retaining projection 61 disposed at the distal end of the
retaining portion 60 is hemispherical or substantially conical, so
that the retaining portion 60 is fitted into the cylindrical bore
54 smoothly.
[0075] Meanwhile, both of the retaining portion 60 and the
cylindrical bore 54 are cylindrical and therefore, can be slightly
deflected about axes of the retaining portion 60 and the
cylindrical bore 54, respectively. Consequently, such a phenomenon
does not happen that it is difficult to insert the retaining
portion 60 into the cylindrical bore 54 due to torsion of the axes
of the small hole 51 and the large hole 53.
[0076] After the retaining portion 60 has been fitted into the
cylindrical bore 54, a small clearance is defined between the
rounded retaining tip 62 and the tip 64 of the fixing slot 63. At
this time, slight assembly oil is held in the clearance.
[0077] Subsequently, when the locking pin 65 is inserted through
the fixing through-hole 55 via the retaining through-hole 59 of the
small end portion 50, the locking pin 65 corrects in an identical
axial direction through deformation of the locking pin 65 small
torsion of the axes of the small hole 51 and the large hole 53
produced at the time of fitting of the retaining portion 60 into
the cylindrical bore 54 so as to fix the retaining portion 60 in
the cylindrical bore 54.
[0078] Furthermore, if torsion of the axes of the small hole 51 and
the large hole 53 is produced due to compressive load, etc. during
operation of the reciprocating compressor K4, the locking pin 65 is
slightly deformed by this torsion and thus, the reciprocating
compressor K4 is well balanced mechanically at a point so as to be
stabilized at the well-balanced point.
[0079] Meanwhile, the connecting rod 40 converts rotation of the
crank shaft 7 into reciprocation of the piston 24. Therefore,
during operation of the reciprocating compressor K4, force is
applied from the large end portion 52 to the small end portion 50
through the cylindrical bore 54 and the retaining portion 60 in all
directions, i.e., in a longitudinal direction of the arrow A and in
a lateral direction of the arrow B in FIG. 12 as well as in a
vertical direction of the arrow C in FIG. 13 but slightly. At this
time, since the retaining projection 61 of the retaining portion 60
is hemispherical or substantially conical, a surface of the
retaining projection 61 faces in all directions. Thus, the axes of
the small hole 51 and the large hole 53 are stabilized in an
identical direction during operation of the reciprocating
compressor K4, so that rotational force of the crank shaft 7 can he
transmitted to the piston pin 23 with substantially no loss at the
retaining portion 60.
[0080] In the above described reciprocating compressor K4, the
large end portion 52 of the connecting rod 40 includes the boss 56
having the cylindrical bore 54 and the fixing through-hole 55
communicating with the cylindrical bore 54, while the bottom of the
cylindrical bore 54 has a hemispherical or substantially conical
shape. The cylindrical bore 54 is formed on the end face 57 of the
boss 56 and extends radially inwardly towards the axis of the large
hole 53 to such a depth as not to open to the large hole 53. The
small end portion 50 includes the cylindrical long rod portion 58
extending radially outwardly from the small hole 51. The retaining
portion 60 having the retaining through-hole 59 and the
hemispherical or substantially conical distal end is provided at
the end portion of the rod portion 58. By loosely fitting or
lightly press fitting the retaining portion 60 into the cylindrical
bore 54 of the boss 56 and inserting the locking pin 65 through the
fixing through-hole 55 via the retaining through-hole 59, the
retaining portion 60 is fixed in the cylindrical bore 54 such that
the axes of the small hole 51 and the large hole 53 of the
connecting rod 40 are maintained on an identical plane.
[0081] Therefore, the reciprocating compressor K4 can be machined
and assembled easily with high precision. In addition, it is
possible to prevent drop of efficiency due to increase of
rotational load caused by torsion of the axes of the small hole 51
and the large hole 53 as well as increase of noises and vibrations
due to abnormal rubbing between the small hole 51 and the piston
pin 23, between the large hole 53 and the eccentric shaft 7a and
between the retaining portion 60 and the cylindrical bore 54.
[0082] FIGS. 14 to 16 show the connecting rod 40 of a reciprocating
compressor K5 according to a fifth embodiment of the present
invention. In FIGS. 14 to 16, a flat fixing portion 70 is formed at
an periphery of the cylindrical bore 54 of the large end portion 52
so as to extend in an axial direction of the cylindrical bore 54.
Since the flat fixing portion 70 is provided on the large end
portion 52, a diameter of a base of the fixing slot 63 is made
smaller than that of the cylindrical bore 54. Meanwhile, a flat
engageable portion 71 is provided on the retaining portion 60 of
the small end portion 50 so as to extend in an axial direction of
the retaining portion 60. Since the flat engageable portion 71 is
provided on the small end portion 50, a diameter of a base of the
retaining projection 61 is made smaller than that of the retaining
portion 60. Since other constructions of the reciprocating
compressor K5 are similar to those of the reciprocating compressor
K4, the description is abbreviated for the sake of brevity.
[0083] When the retaining portion 60 is fitted into the cylindrical
bore 54, the flat engageable portion 71 is brought into engagement
with the flat fixing portion 70 so as to function as a positioning
guide. Therefore, since the retaining through-hole 59 and the
fixing through-hole 55 which are brought out of alignment with each
other slightly simultaneously with fitting of the retaining portion
60 into the cylindrical bore 54 are brought into alignment with
each other highly accurately, the locking pin 65 can be easily
inserted through the fixing through-hole 55 via the retaining
through-hole 59.
[0084] Meanwhile, since movement of the retaining portion 60 about
the axis of the cylindrical bore 54 is regulated by engagement of
the flat engageable portion 71 with the flat fixing portion 70,
behavior of the connecting rod 40 is stabilized.
[0085] In the reciprocating compressor K5, the flat engageable
portion 71 is provided on the cylindrical retaining portion 60 of
the rod portion 58 and the flat fixing portion 70 is provided on
the cylindrical bore 54 of the boss 56 as described above.
Therefore, at the time of assembly of the connecting rod 40, the
fixing through-hole 55 and the retaining through-hole 59 are
brought into alignment with each other highly accurately
simultaneously with fitting of the retaining portion 60 into the
cylindrical bore 54, so that the locking pin 65 can be easily
inserted through the fixing through-hole 55 via the retaining
through-hole 59 and thus, the connecting rod 40 can be assembled
easily.
[0086] Meanwhile, since movement of the retaining portion 60 about
the axis of the cylindrical bore 54 is regulated, behavior of the
connecting rod 40 can be stabilized.
[0087] Furthermore, in the reciprocating compressor K5, the
retaining through-hole 59 is formed on the flat engageable portion
71 and the fixing through-hole 55 is formed on the flat fixing
portion 70. However, it is needless to say that the flat engageable
portion 71 and the flat fixing portion 70 may be arbitrarily
positioned relative to the retaining through-hole 59 and the fixing
through-hole 55, respectively.
[0088] FIGS. 17 and 18 show the connecting rod 40 of a
reciprocating compressor K6 according to a sixth embodiment of the
present invention. In FIGS. 17 and 18, a first oiling hole 75 is
provided in the crank shaft 7 and is communicated with a second
oiling hole 76 provided in the eccentric shaft 7a. The second
oiling hole 76 opens to an upper end face of the eccentric shaft
7a. A lateral oil hole 77 extends radially outwardly from the
second oiling hole 76 so as to be communicated with an oil groove
78 formed on an outer periphery of the eccentric shaft 7a. The
lateral oil hole 77 and the oil groove 78 are disposed at one side
of the eccentric shaft 7a adjacent to an axis of the crank shaft 7.
A communication oil hole 79 extends through the boss 56 of the
large end portion 52 so as to communicate the tip 64 of the fixing
slot 63 and the large hole 53 with each other. Since other
constructions of the reciprocating compressor K6 are similar to
those of the reciprocating compressor K4, the description is
abbreviated for the sake of brevity.
[0089] Hereinafter, operation of the reciprocating compressor K6 of
the above described arrangement is described. In FIGS. 17 and 18,
black dots represents oil particles and arrows indicates flow of
oil. FIG. 17 corresponds to a suction process of the reciprocating
compressor K6, while FIG. 18 corresponds to a compression process
of the reciprocating compressor K6.
[0090] During the suction process of the reciprocating compressor
K6, lubricating oil (not shown) collected at a bottom of the
housing 3 is pushed upwardly to the second oiling hole 76 by
centrifugal pump action of the first oiling hole 75 of the crank
shaft 7 in response to rotation of the reciprocating compressor K6.
Then, the oil particles are introduced from the second oiling hole
76 to the oil groove 78 through the lateral oil hole 77 by
centrifugal force produced by rotation of the eccentric shaft 7a.
Meanwhile, a portion of the oil particles is discharged from the
upper end face of the eccentric shaft 7a into the housing 3.
[0091] Therefore, during the suction process of the reciprocating
compressor K6 as shown in FIG. 17, since the oil groove 78 is
disposed at one side of the eccentric shaft 7a adjacent to the axis
of the crank shaft 7, the oil groove 78 is communicated with the
communication oil hole 79 formed on the large end portion 52 of the
connecting rod 40. Furthermore, the small end portion 50 is pulled
leftwards in FIG. 17, while the large end portion 52 is pulled
rightwards in FIG. 17. As a result, a small gap is produced between
the retaining projection 61 and the fixing slot 63. Therefore, the
oil particles which have reached the oil groove 78 by centrifugal
force pass through the communication oil hole 79 without losing
their inertia force so as to be carried to the small gap between
the retaining projection 61 and the fixing slot 63.
[0092] Meanwhile, during the compression process of FIG. 18, the
oil groove 78 is not communicated with the communication oil hole
79 and the retaining projection 61 and the fixing slot 63 are
subjected to compressive load from the small end portion 50 so as
to depress each other. As a result, the oil particles delivered
into the small gap between the retaining projection 61 and the
fixing slot 63 during the suction process are squeezed between the
retaining projection 61 and the fixing slot 63 and thus, flow to
the locking pin 65 through a minute gap or flow backwardly in the
communication oil hole 79 so as to be discharged from upper and
lower end portions of the eccentric shaft 7a. Meanwhile, the oil
particles drawn into the oil groove 78 via the lateral oil hole 77
act as lubricating-oil between the large hole 53 and the eccentric
shaft 7a.
[0093] Consequently, the lubricating oil is sufficiently supplied
to the retaining projection 61 and the fixing slot 63, which act as
a coupling means of the connecting rod 40. Furthermore, since the
lubricating oil is circulated, the lubricating oil serves also to
cool vicinity of the coupling means of the connecting rod 40.
Accordingly, sliding loss of the connecting rod 40 is lessened and
wear of the connecting rod 40 due to metallic contact between the
retaining projection 61 and the fixing slot 63 can be reduced.
[0094] In the reciprocating compressor K6, since the communication
oil hole 79 is provided so as to communicate the large hole 53 and
the tip 64 of the fixing slot 63 with each other and is
communicated with the oil groove 78 of the eccentric shaft 7a as
described above, the lubricating oil can be sufficiently supplied
to the retaining projection 61 and the fixing slot 63, which act as
the coupling means of the connecting rod 40. Therefore, sliding
loss of the connecting rod 40 is lessened and wear of the
connecting rod 40 due to metallic contact between the retaining
projection 61 and the fixing slot 63 can be reduced.
[0095] Meanwhile, in the reciprocating compressor K6, the oil
groove 78 and the communication oil groove 79 are communicated with
each other during the suction process. However, the oil groove 78
and the communication oil groove 79 may also be communicated with
each other during other processes or at all times.
[0096] FIGS. 19 and 20 show the connecting rod 40 of a
reciprocating compressor K7 according to a seventh embodiment of
the present invention. In FIGS. 19 and 20, a retaining groove 80 is
formed on an outer periphery of the cylindrical retaining portion
60 of the small end portion 50, while a fixing groove 81 is formed
on the boss 56 of the large end portion 52 so as to be partially
communicated with the cylindrical bore 54. A substantially U-shaped
fixing plate 82 for fixing the retaining portion 60 to the
cylindrical bore 54 includes a pair of legs and a hook 83 is
provided at a distal end of each of the legs. Since other
constructions of the reciprocating compressor K7 are similar to
those of the reciprocating compressor K4, the description is
abbreviated for the sake of brevity.
[0097] Hereinafter, operation of the reciprocating compressor K7 of
the above described arrangement is described. When the retaining
portion 60 has been fitted into the cylindrical bore 54, the
retaining groove 80 and the fixing groove 81 coincide in position
with each other. Then, the fixing plate 82 is inserted from the
fixing groove 81 through the retaining groove 80 such that the
hooks 83 of the fixing plate 82 embrace the boss 56 of the large
end portion 52. As a result, the retaining portion 60 is depressed
against the bottom of the cylindrical bore 54 so as to be secured
in position.
[0098] Therefore, since load otherwise born by the retaining
projection 61 and the fixing slot 63 is almost born by the fixing
plate 82, coupling between the small end portion 50 and the large
end portion 52 of the connecting rod 40 can be strengthened,
thereby resulting in stable behavior of the connecting rod 40.
[0099] Accordingly, in the reciprocating compressor K7, the
retaining groove 80 is formed on the outer periphery of the
retaining portion 60 of the small end portion 50 and the fixing
groove 81 is formed on the boss 56 of the large end portion 52 so
as to be communicated with the cylindrical bore 54. Thus, after the
retaining portion 60 has been fitted into the cylindrical bore 54,
the fixing plate 82 having the hooks 83 formed at the distal end of
each of the legs is inserted from the fixing groove 81 through the
retaining groove 80 so as to securely couple the small end portion
50 and the large end portion 52 with each other. Consequently,
since the retaining portion 60 is securely fixed to the cylindrical
bore 54, almost all loads applied to the connecting rod 40 during
operation of the reciprocating compressor K7 are born by the fixing
plate 82 and thus, behavior of the connecting rod 40 can be
stabilized.
[0100] FIGS. 21 and 22 show the connecting rod 40 of a
reciprocating compressor K8 according to an eighth embodiment of
the present invention. In FIGS. 21 and 22, a holder portion 85 is
provided between the rod portion 58 and the retaining portion 60 of
the small end portion 50 and includes an auxiliary flat portion 86
having a flat surface confronting the end face 57 of the boss 56 of
the large end portion 52. Since other constructions of the
reciprocating compressor K8 are similar to those of the
reciprocating compressor K4, the description is abbreviated for the
sake of brevity.
[0101] Hereinafter, operation of the reciprocating compressor K8 of
the above described arrangement is described. When the retaining
portion 60 has been fitted into the cylindrical bore 54, the
auxiliary flat portion 86 is brought into contact with the end face
57 of the boss 56. As a result, since a distance for fitting the
retaining portion 60 into the cylindrical bore 54 can be
determined, the locking pin 65 can be simply inserted through the
fixing through-hole 55 and the retaining through-hole 59 and thus,
the connecting rod 40 can be assembled.
[0102] Meanwhile, since load applied to the connecting rod 40
during a compression process of the reciprocating compressor K8 can
be born by the auxiliary flat portion 86, behavior of the
connecting rod 40 can be stabilized.
[0103] Accordingly, in the reciprocating compressor K8, since the
holder portion 85 having the auxiliary flat portion 86 confronting
the end face 57 of the boss 56 is provided between the retaining
portion 60 and the rod portion 58, the distance for fitting the
retaining portion 60 into the cylindrical bore 54 can be determined
and thus, the connecting rod 40 can be assembled simply. In
addition, since load produced during the compression process is
born by the auxiliary flat portion 86, behavior of the connecting
rod 40 can be stabilized.
[0104] Meanwhile, in the reciprocating compressor K8, the retaining
projection 62 and the fixing slot 63 are provided but may also be
eliminated.
[0105] FIGS. 23 and 24 show the connecting rod 40 of a
reciprocating compressor K9 according to a ninth embodiment of the
present invention. In FIGS. 23 and 24, a second retaining
projection 90 is provided between the rod portion 58 and the
retaining portion 60 of the small end portion 50 and has a pair of
retaining end faces 91 extending in parallel with the axis of the
small hole 51. Meanwhile, the boss 56 of the large end portion 52
has a pair of fixing end faces 92 extending in parallel with the
axis of the large hole 53 and confronting the retaining end faces
91, respectively.
[0106] Hereinafter, operation of the reciprocating compressor K9 of
the above described arrangement is described. When the retaining
portion 60 has been fitted into the cylindrical bore 54, the
retaining end faces 91 are brought into contact with the fixing end
faces 92 so as to determine a distance for fitting the retaining
portion 60 into the cylindrical bore 54 and lateral position of the
retaining portion 60, so that the fixing through-hole 55 and the
retaining through-hole 59 are brought into alignment with each
other highly accurately. As a result, since the locking pin 65 can
be inserted through the fixing through-hole 55 via the retaining
through-hole 59, the connecting rod 40 can be assembled easily.
[0107] Meanwhile, since the second retaining projection 90 prevents
the small end portion 50 and the large end portion 52 from
deviating laterally or about the axis of the retaining portion 60,
coupling between the small end portion 50 and the large end portion
52 of the connecting rod 40 can be strengthened and thus, behavior
of the connecting rod 40 can be stabilized.
[0108] Accordingly, in the reciprocating compressor K9, the second
retaining projection 90 having the retaining end faces 91 extending
in parallel with the axis of the small hole 51 is provided between
the retaining portion 60 and the rod portion 58 of the small end
portion 50, while the fixing end faces 92 extending in parallel
with the axis of the large hole 53 are provided on the boss 56 of
the large end portion 52. Therefore, when the retaining portion 60
has been fitted into the cylindrical bore 54, the retaining end
faces 91 are brought into contact with the fixing end faces 92,
respectively, so that the retaining through-hole 59 and the fixing
through-hole 55 can be brought into alignment with each other
highly accurately and thus, the connecting rod 40 can be assembled
easily. Meanwhile, since the small end portion 50 and the large end
portion 52 can be securely fixed laterally or about the axis of the
retaining portion 60, behavior of the connecting rod 40 can be
stabilized.
[0109] Meanwhile, in the reciprocating compressor K9, the retaining
projection 60 and the fixing slot 63 are provided but may also be
eliminated.
[0110] As is clear from the foregoing, the reciprocating
compressors K4 to K6 comprise: the connecting rod which includes
the small end portion and the large end portion; wherein the small
end portion has the small hole and is coupled with the piston at
the small hole by the piston pin, while the large end portion has
the large hole and is coupled with the eccentric shaft of the crank
shaft at the large hole; wherein the large end portion includes the
boss having the cylindrical bore and the fixing hole communicating
with the cylindrical bore and the cylindrical bore has the
hemispherical or substantially conical bottom; wherein the
cylindrical bore extends from the end face of the boss towards the
center of the large hole to such a depth as not to open to the
large hole; wherein the small end portion includes the cylindrical
rod portion extending radially outwardly from the small hole and
the rod portion is provided, at its one end portion, with the
retaining hole and the retaining portion having the hemispherical
or substantially conical distal end; wherein when the retaining
portion is loosely fitted into or lightly press fitted into the
cylindrical bore of the boss and the locking pin is inserted
through the fixing hole and the retaining hole, the retaining
portion is fixed in the cylindrical bore and the axes of the small
hole of the small end portion and the large hole of the large end
portion are disposed as to be maintained on an identical plane.
[0111] Therefore, in the reciprocating compressors K4 to K6, since
not only machining and assembly can be performed easily with high
precision but torsion of the small hole and the small hole and
abnormal rubbing of the fitting members against the small hole and
the large hole can be prevented, it is possible to prevent drop of
efficiency due to increase of rotational load as well as increase
of noises and vibrations.
[0112] Meanwhile, in the reciprocating compressor K5, since the
flat engageable portion and the flat fixing portion are,
respectively, provided on the cylindrical retaining portion of the
rod portion and the cylindrical bore of the boss, the retaining
portion can be positioned when the retaining portion is fitted into
the cylindrical bore and thus, the connecting rod can be assembled
highly accurately. In addition, rotation of the retaining portion
is prevented through engagement of the flat engageable portion with
the flat fixing portion. Therefore, in the reciprocating compressor
K5, it is possible to prevent drop of efficiency due to increase of
rotational load as well as increase of noises and vibrations.
[0113] Furthermore, in the reciprocating compressor K6, since the
oil hole for communicating the tip of the bottom of the cylindrical
bore and the large hole with each other is formed on the large end
portion and is communicated with the oil groove of the eccentric
shaft of the crank shaft, lubricating oil can be sufficiently
supplied to the retaining portion and the cylindrical bore, so that
wear of the retaining portion and the cylindrical bore due to
metallic contact therebetween can be reduced, thereby resulting in
improvement of reliability.
[0114] Meanwhile, in the reciprocating compressor K7, the retaining
groove and the fixing groove are, respectively, provided on the
cylindrical retaining portion of the rod portion and the boss.
Therefore, when the retaining groove of the rod portion is loosely
fitted into or lightly press fitted into the cylindrical bore of
the boss and the fixing plate is fitted from the fixing groove
through the retaining groove, the retaining portion is retained in
the cylindrical bore. Furthermore, by maintaining the axes of the
small hole and the large hole on an identical plane, coupling
between the retaining portion and the cylindrical bore can be
strengthened by the fixing plate and thus, behavior of the
connecting rod can be stabilized. As a result, in the reciprocating
compressor K7, it is possible to reduce drop of efficiency caused
by increase of rotational load of the reciprocating compressor K7
due to loosening of coupling between the retaining portion and the
cylindrical portion as well as increase of noises and
vibrations.
[0115] Meanwhile, in the reciprocating compressor K8, the holder
portion is provided between the rod portion and the retaining
portion and the auxiliary flat portion of the holder portion is
brought into contact with the end face of the boss at the time the
retaining portion is fitted into the cylindrical bore. Therefore,
in the reciprocating compressor K8, the retaining portion 60 can be
coupled with the cylindrical bore efficiently. Furthermore, since
load produced during compression can be scattered by the auxiliary
flat portion and the end face of the boss, behavior of the
connecting rod can be stabilized. As a result, in the reciprocating
compressor K8, it is possible to reduce drop of efficiency due to
increase of rotational load of the reciprocating compressor K8 as
well as increase of noises and vibrations.
[0116] Moreover, in the reciprocating compressor K9, the second
retaining projection having the retaining end faces extending in
parallel with the axis of the small hole is provided between the
rod portion and the retaining portion and the fixing end faces
extending in parallel with the large hole are provided on the boss
of the large end portion. Therefore, when the small end portion and
the large end portion are coupled with each other, the retaining
end faces 91 are brought into contact with the fixing end faces 92
so as to determine fitting position between the small end portion
and the large end portion. Consequently, since the retaining
portion and the cylindrical bore can be coupled with each other
highly accurately, assembly of the connecting rod is improved.
Furthermore, since the connecting rod is prevented from deviating
laterally or about the axis of the retaining portion of the
connecting rod, behavior of the connecting rod is stabilized. As a
result, in the reciprocating compressor K9, it is possible to
reduce drop of efficiency due to increase of rotational load as
well as increase of noises and vibrations.
[0117] FIGS. 25 to 28 show a reciprocating compressor K10 according
to a tenth embodiment of the present invention. In FIG. 25, a
connecting rod 95 includes a small end portion 100 disposed at its
one end and a large end portion 102 disposed at the other end. The
small end portion 100 has a small hole 101 and is coupled with the
piston 24 by the piston pin 23 loosely fitted into the small hole
101, while the large end portion 102 has a large hole 103 and is
coupled with the crank shaft 7a of the crank shaft 7, which is
loosely fitted into the large hole 103. A dovetail 104 is provided
at one end of a rod 106 of the small end portion 100, while a
dovetail groove 105 is formed on the large end portion 102 so as to
receive the dovetail 104.
[0118] A clamp 107 for preventing vertical movement of the small
end portion 100 and the large end portion 102 in FIG. 25 is
horizontally inserted into engageable slots 109 formed on upper and
lower faces of the large end portion 102 and engageable recesses
108 formed on upper and lower faces of the dovetail 104 of the
small end portion 100 so as to stretch over the large end portion
102 and the dovetail 104 of the small end portion 100 as shown in
FIG. 27. When the clamp 107 has been fitted into the engageable
slots 109 and the engageable recesses 108 as shown in FIG. 28, the
engageable slots 109 and the engageable recesses 108 have different
depths so as to form a step 110. In this embodiment, the engageable
slot 109 is made shallower than the engageable recess 108 as shown
in FIG. 28.
[0119] The clamp 107 has a substantially U-shaped configuration and
includes a pair of retaining legs 111. An oblique portion 112 and a
flat portion 113 are sequentially formed on each of opposed edges
of the retaining legs 111 so as to not only prevent the clamp 107
by the step 110 from being detached from the large end portion 102
but prevent vertical movement of the large end portion 102 and the
small end portion 100.
[0120] Hereinafter, assembly steps of the reciprocating compressor
K10 of the above described arrangement are described with reference
to FIG. 26. The crank shaft 7 is preliminarily mounted in the crank
case 4 and an assembly in which the small end portion 100 is
coupled with the piston 24 by the piston pin 23 is inserted into
the cylinder 4c as shown. Then, the crank shaft 7a of the crank
shaft 7 is inserted into the large hole 103 and the dovetail 104 is
inserted into the dovetail groove 105. Subsequently, the clamp 107
is press fitted into the engageable slots 109 and the engageable
recesses 108 horizontally and thus, assembly of the reciprocating
compressor K10 is completed.
[0121] In the above described arrangement of the reciprocating
compressor K10, the small end portion 100 and the large end portion
102 are positively coupled with each other securely in a stroke
direction of the piston 24 through engagement of the dovetail 104
with the dovetail groove 105 and are prevented by the clamp 107
from being moved vertically. Furthermore, since a clearance of, for
example, about 5 to 20 .mu.ms for permitting the dovetail 104 to be
fitted into the dovetail groove 105 is provided between the
dovetail 104 and the dovetail groove 105, error not only in
parallelism between the small hole 101 and the large hole 103 but
in orthogonality between the eccentric shaft 7a and the cylinder 4c
is reduced, so that extremely high dimensional accuracy is not
required and abnormal rubbing between the components can be
prevented. As a result, loss in mechanical slide and rotational
loss can be reduced.
[0122] FIG. 29 shows the connecting rod 95 of a reciprocating
compressor K11 according to an eleventh embodiment of the present
invention. A pin hole 115 is formed at a boundary between the
dovetail 104 and the dovetail groove 105. A press fitting pin 114
having a C-shaped or spiral cross section is press fitted into the
pin hole 115. In this embodiment, a center of the pin hole 115 is
positioned substantially at the boundary between the dovetail 104
and the dovetail groove 105. However, the center of the pin hole
115 may also be positioned so as to sightly deviate from the
boundary between the dovetail 104 and the dovetail groove 105 such
that the press fitting pin 114 presses one of the dovetail 104 and
the large end portion 102 against the other of the dovetail 104 and
the large end portion 102. Since other constructions of the
reciprocating compressor K11 are similar to those of the
reciprocating compressor K10, the description is abbreviated for
the sake of brevity.
[0123] In the above mentioned arrangement of the reciprocating
compressor K11, the press fitting pin 114 functions to elastically
reduce a clearance between the dovetail 104 and the dovetail groove
105. Furthermore, since a function of preventing abnormal rubbing
between the components is secured by elasticity of the press
fitting pin 114, machining accuracy can be further lowered and
thus, productivity can be raised. In addition, since self-alignment
between the dovetail 104 and the dovetail groove 105 is performed
elastically by press fitting the press fitting pin 114 into the pin
hole 115, vibrations are damped in the minute clearance between the
dovetail 104 and the dovetail groove 105 and noises can be
reduced.
[0124] In the reciprocating compressors K10 and K11, the small end
portion and the large end portion of the connecting rod are coupled
with each other by the dovetail and the dovetail groove and
vertical movement of the small end portion and the large end
portion is prevented by the clamp. Since machining errors can be
eliminated by the minute clearance between the dovetail and the
dovetail groove, machining is facilitated and abnormal rubbing
between the components is reduced during operation, so that loss in
rotation and slide can be lessened.
[0125] In the reciprocating compressors K10 and K11, the step is
formed between the small end portion and the large end portion at
the engageable slots and the engageable recesses. Therefore, by
inserting the clamp into the engageable slots and the engageable
recesses, the clamp is prevented by the step from being detached
from the large end portion so as to be supported positively,
thereby resulting in improvement of assembly.
[0126] In addition, in the reciprocating compressor K11, by press
fitting the press fitting pin into the pin hole formed at the
boundary between the dovetail and the dovetail groove,
self-alignment between the dovetail and the dovetail groove is
performed such that the dovetail is held in close contact with the
dovetail groove, so that minute vibrations can be restrained and
noises can be reduced.
[0127] FIG. 30 shows a reciprocating compressor K12 according to a
twelfth embodiment of the present invention. The reciprocating
compressor K12 includes a connecting rod 120. As shown in FIGS. 31
and 32; a recessed portion 123 is formed on the lower face of the
large end portion 102 of the connecting rod 120 along two sides or
one side of a periphery of the dovetail groove 105 so as to form
retaining faces 124 acting as positioning faces for assembly. Since
other constructions of the reciprocating compressor K12 are similar
to those of the reciprocating compressor K10, the description is
abbreviated for the sake of brevity.
[0128] Hereinafter, assembly steps of the reciprocating compressor
K12 of the above described arrangement are described with reference
to FIG. 30. The crank shaft 7 is preliminarily mounted in the crank
case 4 and an assembly in which the small end portion 100 is
coupled with the piston 24 by the piston pin 23 is inserted into
the cylinder 4c as shown. Then, the crank shaft 7a of the crank
shaft 7 is inserted into the large hole 103 and the dovetail 104 is
inserted into the dovetail groove 105. At this time, the dovetail
104 of the small end portion 100 has degrees of freedom of movement
in a sliding direction S of the piston 24, in a pivotal direction
.beta. of the connecting rod 120 and a rotational direction .zeta.
about an axis of the cylinder 4c as shown in FIG. 33. On the other
hand, the large end portion 102 has degrees of freedom of movement
in a rotational direction .alpha. of the crank shaft 7 and in a
rotational direction .theta. about the eccentric shaft 7a.
Therefore, when the dovetail 104 is fitted into the dovetail groove
105, the recessed portion 123 of the large end portion 102 and an
upper face 125 of the dovetail 104 are initially brought into
contact with each other so as to restrain movement in the
rotational direction .zeta.. Then, two neighboring sides of the
dovetail 104 are regulated by the retaining face 124 such that the
sliding direction S of the small end portion 100, the pivotal
direction .beta., the rotational direction a and the rotational
direction .theta. are defined. Thus, by displacing the large end
portion 102 axially to a predetermined position, the dovetail 104
is fitted into the dovetail groove 105. Subsequently, by press
fitting the clamp 107 into the engageable slots 109 and the
engageable recesses 108 horizontally, assembly of the reciprocating
compressor K12 is completed.
[0129] In the reciprocating compressor K12 of the above described
arrangement, the dovetail 104 and the dovetail groove 105 can be
easily positioned and assembled. Furthermore, the small end portion
100 and the large end portion 102 are positively coupled with each
other securely in the sliding direction S of the piston 24 by the
dovetail 104 and the dovetail groove 105. Meanwhile, vertical
movement of the small end portion 100 and the large end portion 102
is prevented by the clamp 107. Furthermore, since a clearance of,
for example, about 5 to 20 .mu.ms for permitting the dovetail 104
to be fitted into the dovetail groove 105 is provided between the
dovetail 104 and the dovetail groove 105, error not only in
parallelism between the small hole 101 and the large hole 103 but
in orthogonality between the eccentric shaft 7a and the cylinder 4c
is reduced, so that extremely high dimensional accuracy is not
required and abnormal rubbing between the components can be
prevented. As a result, loss in mechanical slide and rotational
loss can be reduced.
[0130] FIG. 34 shows the small end portion 100 of a reciprocating
compressor K13 according to a thirteenth embodiment of the present
invention. In FIG. 34, at one vertex portion of the dovetail 104 of
the small end portion 100 of the reciprocating compressor K13, a
projecting retaining portion 126 having two sides continuous with
those of the dovetail 104 of the reciprocating compressor K13
projects upwardly slightly from an upper face of the dovetail 104.
By bringing the two sides of the projecting retaining portion 126
with those of the dovetail groove 105, the dovetail 104 can be
positioned relative to the dovetail groove 105 quite easily.
[0131] By the above described arrangements of the reciprocating
compressors K12 and K13, the dovetail groove and the dovetail each
having the several degrees of freedom of movement can be positioned
easily and positively and the small end portion and the large end
portion of the connecting rod are coupled with each other by the
dovetail and the dovetail groove such that vertical movement of the
small end portion and the large end portion is prevented by the
clamp. However, since the minute clearance is provided between the
dovetail and the dovetail groove, this clearance reduces machining
errors of the components of the reciprocating compressors K12 and
K13 so as to facilitate machining of the components and lessens
abnormal rubbing between the components during operation so as to
reduce loss in rotation and slide.
[0132] Although the present invention has been fully described in
connection with the preferred embodiments thereof with reference to
the accompanying drawings, it is to be noted that various changes
and modifications are apparent to those skilled in the art. Such
changes and modifications are to be understood as included within
the scope of the present invention as defined by the appended
claims unless they depart therefrom.
* * * * *