Metal working – Method of mechanical manufacture – Prime mover or fluid pump making
Reexamination Certificate
2002-06-13
2004-06-15
Rosenbaum, Irene Cuda (Department: 3726)
Metal working
Method of mechanical manufacture
Prime mover or fluid pump making
C029S557000, C072S356000
Reexamination Certificate
active
06748654
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing a shoe for a compressor.
2. Description of the Related Art
A compressor, that compresses a refrigerant gas, is built into a refrigerating circuit that is used as a vehicle air conditioner or the like. For example, a known variable-displacement type swash-plate compressor has a plurality of cylinder bores
91
a
formed in a cylinder block
91
, as shown in
FIG. 10. A
piston
92
is accommodated within each cylinder bore
91
a
so as to be able to carry out a reciprocating motion. Further, a swash plate
93
is supported by a drive shaft, not shown, such that the swash plate
93
is rotatable synchronously with the drive shaft and is tiltable with respect to the drive shaft. A pair of shoes
94
are provided, on each side of the swash plate
93
, between the swash plate
93
and each piston
92
. As shown in
FIG. 11
, the upper surface of each shoe
94
forms a part of a spherical surface as a spherical surface portion
94
a
, and the lower surface of the shoe forms approximately a plane surface as a plane surface portion
94
b
. A cylindrical portion
94
c
is formed in the middle between the upper portion and the lower portion via a round portion R.
In a compressor having the above structure, the swash plate
93
rotates synchronously with the drive shaft and makes an inclined movement with respect to the drive shaft, and a rotary motion of the swash plate
93
is converted into a linear reciprocating motion of the piston
92
within the cylinder bore
91
a
via the shoes
94
, based on the rotation of the drive shaft, as shown in
FIG. 10. A
suction, a compression, and a discharging of a refrigerant gas are carried out at the head end of the piston
92
, based on these motions. During this period, the spherical surface portion
94
a
of each shoe
94
slides on the surface of a spherical surface seat
92
a
of the piston
92
, and the plane surface portion
94
b
of the shoe slides on the surface of the swash plate
93
. Therefore, the shoe
94
is required to have high size precision and small surface roughness in order to allow smooth sliding.
Conventionally, a shoe
94
has been manufactured according to a cutting process, a forging process, and a finishing process, as follows.
<Cutting Process>
As shown in
FIG. 12
, a wire
70
prepared from SUJ2 (JIS Japanese Industry Standard G4805) as a high carbon chrome bearing steel is provided first. This wire
70
is cut into pieces to obtain cut pieces
71
in a cutting process S
90
.
<Forging Process>
Next, in a forging process S
91
, each cut piece
71
is forged with a lower die
95
a
and an upper die
95
b
, by using a forging die
95
that has a single cavity
95
c
to form a sphere as shown in FIG.
13
. As a result, an approximately spherical steel sphere
72
having a slight flash
72
a
is obtained as shown in FIG.
14
.
<Finishing Process>
Then, the following finishing process S
92
is carried out as shown in FIG.
12
. First, in a flash removing (deburring) process S
92
a
, a flash (a burr) is removed by sandwiching the steel sphere
72
between two rotary casting boards, not shown, and by rotating the casting boards, thereby to obtain a flash-removed ball
73
.
Next, in a heat treating process S
92
b
, a hardening and a tempering are carried out to obtain a heat-treated ball
74
.
In a grinding process S
92
c
, the heat-treated ball
74
is ground with a casting board similar to that explained above and is ground with a grindstone, thereby to obtain a ground ball
75
. The hard ground ball
75
obtained in this way can also be used as a ball of a rolling bearing.
Further, the ground ball
75
is annealed in an annealing process S
92
d
, thereby to obtain an annealed ball
76
that has a slightly lower hardness than that of the ground ball
75
and that has any internal distortion removed.
Then, in a rotary grinding process S
92
e
, the annealed balls
76
and a slurry are put into a rotary grinder not shown, and are rotated together. As a result, the annealed balls
76
are brought into contact with each other, and are mutually ground. Gloss is added to these balls, and stains adhered to the surfaces of these balls are removed.
Further, in a cleaning process S
92
f
, an ultrasonic cleaning is carried out to remove slight stains adhered to the surfaces. A visual inspection process S
92
g
is carried out, and an anticorrosive is coated onto the balls in an anticorrosive processing process S
92
h
. As a result, a raw ball
77
having a true spherical shape is obtained.
In a pressing process S
92
i
, the raw ball
77
is pressed to obtain a material
78
formed in a shoe shape.
Further, in a heat treating process S
92
j
, a hardening and a tempering are carried out. Then, the shoe-shaped material is ground to obtain a shoe shape and a surface coarseness within a standard, in a finish grinding process S
92
k
. The shoe-shaped material is further cleaned in a cleaning process S
92
l
, and is dried in a drying process S
92
m
to finally obtain a shoe
94
for a compressor.
The conventional manufacturing method employs the flash removing process S
92
a
. Therefore, the grinding process S
92
c
and the rotary grinding process S
92
e
are necessary. As the steel sphere
72
is obtained in one process of the forging process S
91
by using the forging die
95
consisting of the lower die
95
a
and the upper die
95
b
, it is difficult to obtain a desired shape. Therefore, the cut piece
71
having a slightly larger volume than that of a desired shoe is obtained. This cut piece
71
has a flash (burr)
72
a
. As a slight gap is formed between the upper die
95
b
and the lower die
95
a
of the forging die
95
, the flash
72
a
occurs in this gap. The obtained steel sphere
72
having the flash
72
a
is further subjected to the flash removing process S
92
a
, the grinding process S
92
c
, and the rotary grinding process S
92
e
. Based on these processes, dispersion in the volume of the raw ball
77
is eliminated. The raw ball
77
that has approximately the same volume as that of the desired shoe
94
is pressed in the pressing process S
92
i
. As a result, the shoe-shaped material
78
also has a constant volume, and the finally-obtained shoe
94
for a compressor has high size precision. The obtained shoe
94
has small surface roughness after the heat treating process S
92
j
and the finish grinding process S
92
k.
According to the above conventional manufacturing method, however, the shoe
94
is manufactured from the raw ball
77
, after the raw ball
77
has been manufactured.
In other words, according to the conventional manufacturing method, the steel sphere
72
after the forging process S
91
is further subjected to many processes including the flash removing process S
92
a
, the heat treating process S
92
b
, the grinding process S
92
c
, the annealing process S
92
d
, and the rotary grinding process S
92
e
. The raw ball
77
is completed through the above processes. Thereafter, the raw ball
77
is again subjected to the pressing process S
92
i
that deforms the raw ball
77
to obtain the material
78
. This material
78
is then subjected to the heat treating process S
92
j
, and the finish grinding process S
92
k
. Therefore, an extremely large number of processes are carried out on the wire
70
. Consequently, the process takes a long time, and is expensive.
SUMMARY OF THE INVENTION
The present invention has been made in the light of the above problems. It is, therefore, an object of the present invention to provide a method of manufacturing a shoe for a compressor that can shorten the manufacturing time and can reduce the manufacturing cost.
In order to achieve the above object, according to a first aspect of the present invention, there is provided a method of manufacturing a shoe for a compressor comprising: a cutting process that cuts a steel wire to obtain cut pieces; a forging process that forges each cut piece to obtain a steel sphere; and a finishing process that ob
Miura Yasuhiro
Mukai Takamitsu
Tomita Masanobu
LandOfFree
Method of manufacturing shoe for 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 Method of manufacturing shoe for compressor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of manufacturing shoe for compressor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3360881