Metal working – Method of mechanical manufacture – Prime mover or fluid pump making
Reexamination Certificate
2001-12-04
2003-11-25
Jordan, Charles T. (Department: 3644)
Metal working
Method of mechanical manufacture
Prime mover or fluid pump making
C029S890090, C419S026000, C419S028000, C419S029000
Reexamination Certificate
active
06651328
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for manufacturing a sliding part for a hermetic compressor, and more particularly, to a method for manufacturing a sliding part for a hermetic compressor that is capable of improving an abrasion resistance of a sliding part and capable of shortening a manufacturing process.
2. Description of the Background Art
FIG. 1
is a sectional view of a general hermetic compressor.
In general, the hermetic compressor includes a hermetic case
6
in which a suction pipe
2
into which fluid is sucked from an external source and a discharge pipe
4
for discharging compressed fluid are connected, a drive unit
8
being disposed at a lower portion of the case
6
and generating a rotational force, and a compressing unit
10
being disposed at an upper portion of the case
6
and compressing the fluid according to the rotational force generated by the drive unit
8
.
The drive unit
8
includes a stator
12
being disposed fixed at the inner circumference of the case
6
, to which power is applied from an external source, a rotor
14
being disposed at an inner circumference of the stator
12
with a certain distance and rotated by electromagnetic interacting with the stator
12
when power is applied to the stator
12
, and a crank shaft
18
being fixed at the rotor
14
and rotated accordingly and supported at a frame
16
fixed at the case
6
.
The compression unit
10
includes a connecting rod
20
being connected to the upper end of the crank shaft
18
and making a reciprocating and linear movement according to a rotational movement of the crank shaft
18
, a cylinder
22
being disposed fixed at an upper side of the frame
16
and having a space to which a fluid is provided, a piston
24
being connected to the connecting rod
20
for a linear movement together with the connecting rod
20
, and slidably disposed inside the cylinder to compress fluid introduced into the cylinder, and a valve assembly
26
being mounted at one side of the cylinder
22
to supply fluid into the cylinder
22
and discharging a coolant compressed by the piston
24
.
When such a hermetic compressor is driven for a fluid compression operation, friction is created between the crank shaft
18
and the frame
16
, friction is created between the piston
24
and the inner wall of the cylinder
22
, and friction is also created between the connecting rod
20
and the crank shaft
18
.
Thus, the surface of sliding parts where friction is generated is to be surface-processed to increase lubrication and abrasion resistance.
A method for manufacturing a sliding part of a conventional art will now be described by taking an example of the piston
24
.
The piston is manufactured by using a sintering and casting method for a mass production.
First, a method for manufacturing the piston
24
by sintering will now be described with reference to FIG.
2
.
A material of ferrite group is pressed to form an exterior and subjected to sintering at a high temperature to obtain a compact organization and increase an adhesiveness between organizations (step S
100
).
After the sintering process, a steam treatment is carried out to maintain air tightness according to closure of pores formed in the organizations of the sintered product and increase corrosion resistance and abrasion resistance (step S
200
).
After the steam treatment, a roughing process is performed to process a shape of an inner and outer diameter (step S
300
).
After the roughing process, in order to improve a surface roughness of the sintered product, a sand blasting process is performed (step S
400
).
After the sand blasting process, in order to improve lubrication and abrasion resistance on a plastic deformation processed surface, a manganese phosphate coating treatment, a kind of lubricating treatment, is performed to form a coated layer
102
(step S
500
).
After the manganese phosphate coating process, molybdenum desulfidel treatment serving as a lubricant is carried to form a coated layer
104
at the surface of the piston (step S
600
).
According to a piston manufacturing method by a casting is that molten metal having a dissolved ferrite-group material is poured in a molding box to process a shape of a piston and then the same process as that of the piston manufacturing method by sintering as described above is performed to finally manufacture a piston.
The manganese phosphate coating process is a kind of phosphate coating process and performed for the purpose of a base of a paint, improvement of abrasion resistance, lubrication of plastic deformation process and electric insulation, for which phosphate solution of various metals is used suitable to the purpose.
For the molybdenum desulfide treatment process, a method is used in which the molybdenum desulfide(MoS
2
) is made to be powders or coated on a surface of the metal by mixing it with grease or oil.
After the piston manufacturing process of the conventional art is completed, as shown in
FIG. 3
, dual soft-coated layers
102
and
104
are formed at the surface of the piston by the manganese phosphate and molybdenum disulfide.
However, the coated layers
102
and
104
of the piston
24
, the soft-coated layer, have a problem that as a predetermined time elapses, a gap (L) is generated due to a friction according to sliding with the cylinder
22
, into which a coolant is leaked.
In addition, the conventional method for manufacturing a sliding part for a hermetic compressor has a problem that since the dual surface treatment process that the manganese phosphate treatment process and the molybdenum disulfide treatment process are subsequently performed is carried out, its production cost is increased, and especially, in case of the molybdenum disulfide surface processing, its unit cost is so high that its production cost is inevitably increased.
Moreover, because of the dual process performing the manganese phosphate treatment and the molybdenum disulfide treatment are subsequently performed, the thickness is increased due to the respective surface processing, causing exceeding the tolerance and the size deficiency occurs.
That is, When the thickness is increased in the surface treatment process of the piston, it is difficult to assembly the piston into the cylinder, and the fluid may be leaked due to the irregular surface of the piston in working.
Furthermore, due to the performing of the dual surface treatment of the piston, the size is changed when the piston and a piston pin are assembled, considerably degrading a combination rate, and it is difficult to compute a design size corresponding to the fact that the piston pin is released from the piston.
In addition, since the surface treatment process of the sliding part is dually performed, resultantly, the process is complicated, the manufacturing process duration is increased, and a defective generation rate is increased.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a method for manufacturing a sliding part for a hermetic compressor that is capable of simplifying a process and reducing a production cost and working time period by reducing a surface treatment process of a manufacturing process of a sliding part.
Another object of the present invention is to provide a method for manufacturing a sliding part for a hermetic compressor that is capable of facilitating assembling of sliding parts and improving a reliability in operation and abrasion resistance by minimizing a change in the thickness according to a surface treatment of the sliding parts and reducing a tolerance.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a method for manufacturing a sliding part for a hermetic compressor including the steps of: sintering a powder material of a ferrite group and forming a shape of a sliding part; performing a first stream treatment to close air pores formed in the organization of the sliding part after the si
Jordan Charles T.
LG Electronics Inc.
Nguyen T.
Ostrolenk Faber Gerb & Soffen, LLP
LandOfFree
Method for manufacturing sliding parts for hermetic 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 for manufacturing sliding parts for hermetic compressor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for manufacturing sliding parts for hermetic compressor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3142749