KR102351707B1 - Piston for reciprocating compressor and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a piston of a reciprocating compressor and a method for manufacturing the same.
In the piston of the reciprocating compressor according to an embodiment of the present invention, the first part is formed in the front part of the piston and slides on the inner circumferential surface of the cylinder, and is formed in the rear part of the piston and has the same outer diameter as the outer diameter of the first part A fourth part with
In the method of manufacturing the piston, a plurality of second parts extending rearward of the first part and having the same outer diameter as the first part and a pin through hole positioned between the plurality of second parts and into which the piston pin is inserted processing a third part having a; The method further includes processing a fifth part forming an intermediate step between the first part and the fourth part, and cutting the fourth part and the fifth part.

Description

Piston for reciprocating compressor and manufacturing method therefor {Piston for reciprocating compressor and method for manufacturing the same}

An embodiment of the present invention relates to a piston of a hermetic compressor and a method for manufacturing the same.

A reciprocating compressor refers to a device that compresses a fluid by suctioning, compressing, and discharging a refrigerant through a reciprocating motion of a piston in a cylinder. The reciprocating compressor may be divided into a connection type reciprocating compressor and a vibration type reciprocating compressor according to a driving method of a piston. Here, the connected reciprocating compressor is a method of compressing refrigerant by reciprocating motion in a cylinder of a piston connected to the rotating shaft of the drive unit through a connecting rod and a piston pin, and the vibratory reciprocating compressor is connected to the mover of the reciprocating motor to vibrate It is a method of compressing the refrigerant by reciprocating motion in the cylinder of the piston.

A connection-type reciprocating compressor is disclosed in the first prior art (Korean Patent Publication No. 10-2010-0085760, publication date: July 29, 2010, title of invention: reciprocating compressor). The connected reciprocating compressor disclosed in the first prior art includes a housing shell forming a closed space, a driving unit provided in the housing shell and providing driving force, and connected to a rotation shaft of the driving unit, and using driving force from the driving unit to enter the cylinder It includes a compression unit for compressing the refrigerant by the reciprocating motion of the piston, and a suction/discharge unit for sucking the refrigerant and discharging the compressed refrigerant through the reciprocating motion of the compression unit.

A discharge hose through which the compressed refrigerant is discharged is connected to the suction/discharge unit, and the discharge hose is coupled to a discharge pipe coupled to a shell of the compressor.

The piston reciprocates at high speed within the cylinder. A portion of the outer circumferential surface of the piston that slides within the cylinder may form a sliding portion, and a portion to which the connecting rod and the piston pin are connected may not form a sliding portion.

The structure of such a piston is disclosed in the second prior art (Japanese Patent No. 6,048,849, registration date: December 2, 2016, title of invention: hermetic compressor and refrigerator). According to the piston disclosed in the second prior art, the area of the part (non-sliding part) not forming the sliding part is relatively large, so the mass of the piston is increased, and thus there is a problem in that vibration and noise are increased during operation of the compressor.

In order to solve the above problems, an object of the present invention is to provide a piston of a reciprocating compressor capable of reducing the mass of a piston reciprocating within a cylinder, and a method for manufacturing the same.

In particular, an object of the present invention is to provide a piston of a reciprocating compressor capable of reducing the mass of a piston by removing an unnecessary part for a sliding action of the piston after machining the piston to form a sliding part and a non-sliding part, and a method for manufacturing the same.

The piston of the reciprocating compressor according to an embodiment of the present invention is connected to a connecting rod through a piston pin, reciprocates inside the cylinder, and has a cylindrical shape.

The piston includes a first part formed in the front part of the piston and sliding on the inner circumferential surface of the cylinder and a fourth part formed in the rear part of the piston and having the same outer diameter as the outer diameter of the first part.

In the method of manufacturing the piston, a plurality of second parts extending to the rear of the first part and having the same outer diameter as the first part and a plurality of second parts are positioned between the plurality of second parts and the piston pin is inserted through the pin machining a third part having the hole is included.

The manufacturing method further includes processing a fifth part forming an intermediate step between the first part and the fourth part, and cutting the fourth part and the fifth part.

The fifth part may include a groove recessed from the outer circumferential surface of the piston, and may have a ring shape.

The outer peripheral surface of the piston includes a first inclined portion extending from the front end of the fifth part to the second part and a second inclined portion extending from the rear end of the fifth part to the fourth part.

An outer diameter of the fifth part may be smaller than outer diameters of the second part and the fourth part.

The first and second inclined portions may extend obliquely outwardly in a radial direction.

An outer diameter of the fifth part may be larger than an outer diameter of the third part.

The cutting of the fourth part and the fifth part includes performing the cutting using a cutting line extending in a radial direction at a point where the first inclined portion and the fifth part meet.

When the cutting of the fourth part and the fifth part is completed, an end of the first inclined portion forms a rear end of the piston.

The machining of the second part and the third part includes supporting the piston on a support and placing it between the first and second rollers to perform centerless grinding.

In the step of processing the second part and the third part,

Supporting the piston on a support and placing it between the first and second rollers to perform centerless grinding.

A plurality of the second parts may be provided, and the plurality of second parts may be spaced apart from each other and provided on both sides of the rear surface of the first part.

The first and second parts may form a sliding portion in contact with the inner circumferential surface of the cylinder.

According to the above solution, by reducing the mass of the piston, vibration or noise that may be generated during operation of the compressor can be reduced.

In particular, by reducing the mass of the piston, it is possible to reduce the size of an unbalanced force that may be generated in the process of the piston reciprocating forward and backward, so that the wear of the piston sliding part can be reduced.

In addition, since the fifth part necessary in the process of machining the outer surface of the piston can be removed (cut) after machining the piston, there is an advantage that the mass of the piston can be easily reduced.

In addition, by forming a cut surface on the fourth part connecting the sliding part of the piston and the fifth part, there is an effect that it is possible to reduce the occurrence of deformation of the piston sliding part during the cutting process.

1 is a cross-sectional view showing the configuration of a reciprocating compressor according to an embodiment of the present invention.
2 is a plan view showing a partial configuration of a reciprocating compressor according to an embodiment of the present invention.
3 is a cross-sectional view illustrating a state in which a piston is disposed in a cylinder of a reciprocating compressor according to an embodiment of the present invention.
4 is a perspective view showing the configuration of a piston according to an embodiment of the present invention.
5 is a view showing a piston base material used to manufacture a piston according to an embodiment of the present invention.
6 is a schematic view showing a state of processing the piston base material according to an embodiment of the present invention using a roller device.
7 and 8 are views showing a state in which a plurality of parts are formed on the outer circumferential surface of the piston by processing the piston base material according to an embodiment of the present invention.
FIG. 9 is an enlarged view of part “A” of FIG. 7 .
FIG. 10 is a view showing a state in which a cutting process is performed on the piston in the intermediate stage of manufacture shown in FIGS. 7 and 8 .
11 is a cross-sectional view taken along line I-I' of FIG. 4 .
12 is a flowchart showing a method of manufacturing a piston according to an embodiment of the present invention.

1 is a cross-sectional view showing a configuration of a reciprocating compressor according to an embodiment of the present invention, FIG. 2 is a plan view showing a partial configuration of a reciprocating compressor according to an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention It is a cross-sectional view showing the arrangement of the piston in the cylinder of the reciprocating compressor.

1 to 3 , in the reciprocating compressor 10 according to an embodiment of the present invention, a shell 11 having a closed space and driving units 12 and 13 disposed inside the shell 11 are provided. Included. The driving units 12 and 13 include a stator 12 and a rotor 13 disposed inside the stator 12 .

A suction pipe 15 for sucking the refrigerant and a discharge pipe (not shown) for discharging the compressed refrigerant may be coupled to the shell 11 . In addition, a suction muffler 20 for reducing noise of the refrigerant sucked through the suction pipe 15 may be coupled to the suction pipe 15 .

The reciprocating compressor 10 further includes a rotation shaft 15 coupled to a central portion of the rotor 13 and a cylinder block 30 supporting an upper portion of the rotation shaft 15 . A shaft support part 32 supporting the rotation shaft 15 is included in a lower portion of the cylinder block 30 , and the rotation shaft 15 is inserted into the shaft support part 32 to rotate.

A spring 19 for absorbing vibration transmitted to the stator 12 when the rotor 13 rotates is provided at a lower portion of the stator 12 . The spring 19 is coupled to the lower portion of the shell 11, and may be configured in plurality.

In the reciprocating compressor 10 , an eccentric portion 16 is provided on the upper portion of the rotation shaft 15 and has a central portion eccentric from the center of the rotation shaft 15 , and a sleeve coupled to the outer circumferential surface of the eccentric portion 16 . (17) is further included.

The reciprocating compressor 10 further includes a connecting rod 40 coupled to the outside of the sleeve 17 and converting the rotational motion of the rotary shaft 15 into a linear motion. A counterweight 18 may be provided at a lower portion of the eccentric portion 16 to balance parts moving in the shell 10 .

The cylinder block 30 includes a cylinder 50 forming a compression chamber 55 . A piston 100 provided to be reciprocating may be disposed inside the cylinder 50 . The piston 100 may be coupled to the connecting rod 40 .

A volume spacer 102 may be provided on the front portion 101 of the piston 100 to reduce a dead volume formed in the discharge hole 73 . The volume spacer 102 may be deflected from the center of the front part 102 and protrude, and may be inserted into the discharge hole 73 when the piston 100 moves to top dead center.

define the direction A direction in which the piston 100 advances and compresses the refrigerant, that is, a right direction with reference to FIG. 1 is defined as "front", and the opposite direction is defined as "rear". In addition, the front and rear may be collectively referred to as “axial direction”, and a direction perpendicular to the axial direction may be referred to as “radial direction”.

The rear portion of the piston 100 is opened to form an opening 103 (refer to FIG. 4 ), and at least a portion of the connecting rod 40 may be inserted into the opening 103 .

A pin through hole 105 into which the piston pin 60 is inserted may be formed in the piston 100 . The singi pin through-hole 105 may be formed at a position eccentric to the front from the reference center in the front-rear direction of the piston 100 . The piston pin 60 may be inserted into the pin through hole 105 to connect the connecting rod 40 and the piston 100 .

The reciprocating compressor (10) is provided on one side of the cylinder (50) so that the refrigerant is sucked into the compression chamber (55) of the cylinder (50), or the refrigerant compressed in the compression chamber (55) is discharged. A valve assembly 70 for guiding to do so may be included. The valve assembly 70 may include a suction hole 71 through which the suction refrigerant flows and a discharge hole 73 through which the discharge refrigerant flows.

In addition, a head cover 75 for separating the suction refrigerant and the discharge refrigerant may be provided on one side of the valve assembly 70 . The head cover 75 may be coupled to the upper side of the suction muffler 20 .

An oil supply part 82 for sucking in the oil 80 stored in the bottom of the shell 10 may be installed at a lower portion of the rotation shaft 15 . And, supplying the oil 80 sucked by the oil supply unit 82 into the rotating shaft 15, the connecting rod 40, the cylinder 50, the piston 100, etc. An oil flow path 84 for the may be formed.

4 is a perspective view showing the configuration of a piston according to an embodiment of the present invention.

4, the piston 100 according to the embodiment of the present invention may have a cylindrical shape. In detail, the piston 100 includes a front portion 101 facing the compression chamber 55 of the cylinder 50 and a rear portion 106 having an opening 103 to which the connecting rod 40 is connected.

The piston 100 may reciprocate while moving forward in a direction in which the front part 101 compresses the compression chamber 55 or backward in a direction in which the compression chamber 55 expands. A position in which the piston 100 maximizes the compression of the compression chamber 55 is referred to as a top dead center (TDC), and the piston 100 maximizes the expansion of the compression chamber 55 . The position of the state can be called the Bottom Dead Center (BDC). That is, the piston 100 may reciprocate between the top dead center (TDC) and the bottom dead center (BDC).

The volume spacer 102 is provided on the front part 101 of the piston 100 . In addition, a rod coupling portion 104 to which the connecting rod 40 is coupled is provided on the rear portion 106 of the piston 100 . The piston 100 may be understood as a component extending forward and backward from the front portion 101 toward the rear portion 106 .

The piston 100 includes an outer peripheral surface that slides with respect to the inner surface of the cylinder 50 . A first part 110 , a second part 130 , and a third part 150 are included on the outer peripheral surface of the piston 100 .

The first part 110 may be located in a front portion of the outer circumferential surface of the piston 100 and may have a ring shape having a predetermined width in the front and rear directions. The outer diameter of the first part 110 may be formed to be slightly smaller than the inner diameter of the inner circumferential surface of the cylinder 50 . Accordingly, the outer circumferential surface of the first part 110 forms a first gap with the inner circumferential surface of the cylinder 50 .

Lubricating oil 80 is supplied to the first gap, and the compression chamber 55 may be sealed by the lubricating oil 80 . Also, the first part 110 may slide while being in contact with the inner circumferential surface of the cylinder 50 through the lubricant 80 . Accordingly, the first part 110 may be referred to as a “first sliding unit” or a “first sliding unit”.

The second part 130 may be configured to extend rearwardly from the rear side of the first part 110 . For example, the second part 130 includes an arc surface having a substantially rectangular or square shape.

In addition, a plurality of second parts 130 may be provided, and the plurality of second parts 130 may be spaced apart from each other. For example, two second parts 130 may be provided, and the two second parts 130 may be provided on both sides of the rear surface of the first part 110 .

The outer diameter of the second part 130 may be slightly smaller than the inner diameter of the inner circumferential surface of the cylinder 50 . For example, the outer diameter D1 (refer to FIG. 8 ) of the first part 110 and the outer diameter D1 (refer to FIG. 8 ) of the second part 130 may be the same. Accordingly, the outer circumferential surface of the second part 130 forms a second gap with the inner circumferential surface of the cylinder 50 .

Lubricating oil 80 is supplied to the second gap, and the second part 130 may slide while being in contact with the inner circumferential surface of the cylinder 50 through the lubricating oil 80 . Accordingly, the second part 130 may be referred to as a “second sliding part” or a “second sliding part”.

The third part 150 may be configured to extend rearwardly from the rear side of the first part 110 . In addition, the pin through hole 105 may be formed to penetrate through the third part 150 .

The third part 150 may be understood as a portion extending in a circumferential direction between the plurality of second parts 130 among the outer peripheral surfaces formed on the rear side of the first part 110 . As described above, when the second part 130 is composed of two, the third part 150 may be composed of two on the outer circumferential surface between the two second parts 130 .

The third part 150 may be configured to be more depressed than the first part 110 or the second part 130 . For example, the third part 150 may be further cut from the outer peripheral surfaces of the first and second parts 110 and 130 in the inner radial direction. Accordingly, the outer diameter D2 of the third part 150 (refer to FIG. 8 ) may be smaller than the outer diameter D1 of the first and second parts 110 and 130 .

Accordingly, a third gap may be formed between the third part 150 and the inner circumferential surface of the cylinder 50 , and the gap between the third gap may be greater than the gap between the first gap or the second gap. . According to this configuration, in the process of the piston 100 reciprocating, the third part 150 does not come into contact with the inner circumferential surface of the cylinder 50 and forms a "non-sliding part" or "non-sliding part". .

The rear end of the second part 130 and the rear end of the third part 150 may form the rear surface 106 of the piston 100 . The fourth part 170 generated during the processing of the piston 100 is cut in the final processing step, and accordingly, the rear ends of the second and third parts 130 and 150 form the rear surface 106 of the piston 100. do. A detailed description thereof will be described later with reference to the drawings.

Figure 5 is a view showing a piston base material used to manufacture a piston according to an embodiment of the present invention, Figure 6 is a schematic view showing a state of processing the piston base material according to an embodiment of the present invention, using a roller device 7 and 8 are views showing a state in which a plurality of parts are formed on the outer circumferential surface of the piston by processing the piston base material according to an embodiment of the present invention, and FIG. 9 is an enlarged view of part "A" of FIG. , and FIG. 10 is a view showing a state in which a cutting process is performed on the piston in the intermediate stage of manufacture shown in FIGS. 7 and 8, and FIG. 11 is a cross-sectional view taken along I-I' in FIG. It is a flowchart showing a method of manufacturing a piston according to an embodiment of the present invention.

5 to 12 , the piston 100 according to the embodiment of the present invention may be manufactured by processing the piston base material 100a. Hereinafter, a method of manufacturing the piston 100 will be described.

The piston base material 100a is formed in a cylindrical shape. In addition, the opening 105 and the rod coupling portion 104 may be formed in the piston base material 100a through casting or internal processing.

The apparatus for processing the outer circumferential surface of the piston 100 includes roller apparatuses 200 and 300 and a support 400 .

In detail, the piston base material 110a is supported on the support 400 and is positioned between the first and second rollers 200 and 300 to perform centerless grinding. In the process of performing the centerless grinding, the piston base material 100a has a first part 110 , a second part 130 , a third part 150 , a fourth part 170 , and a fifth part 180 . ) can be formed.

For example, on the outer circumferential surface of the piston base material 100a, the first part 110, the second part 130, and the fourth part 170 having the largest diameter may be processed first. Thereafter, the fifth part 180 having a smaller diameter than the first, second, and fourth parts 110, 130, and 170 is machined, and finally, the third part 150 having the smallest diameter among the piston 100 is machined. can

The outer circumferential surface of the piston base material 100a may be processed in the course of rotation using the roller devices 200 and 300 . The roller devices 200 and 300 include a first roller 200 and a second roller 300 .

The first and second rollers 200 and 300 may be disposed to be spaced apart from each other, and the piston base material 100a may be positioned between the first and second rollers 200 and 300 . In addition, the outer peripheral surface of the piston base material 100a may be cut or surface treated while rotating the first and second rollers 200 and 300 .

The first roller 200 includes a grinding wheel for processing the piston base material (100a). And, the second roller 300 includes an adjustment wheel for adjusting the processing position of the piston base material (100a). For example, the first roller 200 and the second roller 300 rotate in a clockwise direction, and the piston base material 100a may be processed while rotating in a counterclockwise direction.

A support 400 for supporting the piston base material 100a may be provided under the piston base material 100a. When processing the piston base material 100a using the first and second rollers 200 and 300 , the front and rear portions of the piston base material 100a need to be stably supported.

If, when the movement of the piston base material (100a) occurs, there is a problem that the processing precision is lowered. In order to prevent such a problem, the front and rear portions of the piston base material 100a have the same outer diameter, so that they can be stably supported by the support 400 .

In more detail, referring to FIG. 7 , in the process of machining the piston base material 100a , a front part of the outer peripheral surface of the piston base material 100a may be machined to form the first part 110 . In addition, a rear portion of the outer circumferential surface may be processed to form a fourth part 170 having the same outer diameter as that of the first part 110 .

In addition, the piston base material 100a may be processed by the first and second rollers 200 and 300 in a state in which the first part 110 and the fourth part 170 are supported. That is, the fourth part 170 may be understood to form the most important sliding part of the piston 100 , that is, a supporting outer circumferential surface necessary for processing the first part 110 and the second part 130 . .

Meanwhile, in the process of processing the outer peripheral surface of the piston base material 100a, the fifth part 180 recessed from the outer peripheral surface of the piston base material 100a may be formed. The fifth part 180 is understood as an “intermediate step” formed on the outer circumferential surface of the piston base material 100a, and has a ring shape positioned between the second part 130 and the fourth part 170 . includes home.

In detail, the fifth part 180 is a part defining the rear end of the second part 130, and when performing a process of removing an unnecessary part of the piston base material 100a later, the sliding part of the piston, that is, the first It may be processed so as not to cause deformation of the first part 110 and the second part 130 . The rear portions of the plurality of third parts 150 may be connected to each other by the fifth part 180 .

The outer diameter of the fifth part 180 may be smaller than the outer diameter D1 of the first and second parts 110 and 130 and larger than the outer diameter D2 of the third part 150 .

In the process of processing the piston base material 100a, on the outer peripheral surface of the piston base material 100a, a first inclined portion 181 extending from the front end of the fifth part 180 to the second part 130 and A second inclined portion 183 extending from the rear end of the fifth part 180 to the fourth part 170 is included. Since the outer diameter of the fifth part 180 is formed to be smaller than the outer diameter of the second and fourth parts 130 and 170 , the first and second inclined portions 181 and 183 may be inclined to extend outwardly in the radial direction ( S11 and S12 ). ).

When the processing and surface treatment of the first part 110 and the second part 130 as a "sliding part" are completed, and the processing of the third part 150 as a non-sliding part is completed, the fourth part 170 and a process of removing the fifth part 180 may be performed. The fourth part 170 and the fifth part 180 do not function as a sliding part of the piston 100 and may be removed as unnecessary parts that increase the mass of the piston 100 (cutting process).

In detail, referring to FIG. 10 , the fifth part 180 and the fourth part 170 may be cut and removed. As described above, the fifth part 180 is a portion formed in the machining process of the piston base material 100a before the cutting process, and may act as a guide groove for forming a cut surface.

In addition, by performing the cutting based on the fifth part 180 when performing the cutting process using a cutting tool, it is possible to prevent the stress generated in the cutting process from acting on the first and second parts 110 and 130 . can As a result, deformation of the first and second parts 110 and 130 may be reduced.

For example, the cutting line CL for cutting the fourth and fifth parts 170 and 180 may be formed to extend in a radial direction at a point where the first inclined portion 181 and the fifth part 180 meet. have. Therefore, after performing the cutting process, the rear end of the first inclined portion 181 forms the rear end of the piston base material 100a.

When the cutting process is completed, the manufacture of the piston 100 is completed, and the piston 100 has a configuration as shown in FIG. 4 . And, the rear end of the piston 100 is to form a cut surface 188 (S13).

In this way, in the machining process of the piston, the fourth part 170 and the fifth part 180, which are necessary for processing precision and processing efficiency, but are not required for the function of the piston 100, can be removed, so that the piston The mass of (100) can be reduced.

10: reciprocating compressor 15: rotary shaft
40: connecting rod 50: cylinder
60: piston pin 100: piston
102: volume spacer 105: pin through hole
110: first part 130: second part
150: third part 170: fourth part
180: fifth part 181: first inclined portion
183: second inclined portion 200: first roller
300: second roller 400: support

Claims (12)

In the method of manufacturing a piston connected to a connecting rod through a piston pin and reciprocating inside a cylinder, and having a cylindrical shape,
The piston includes a first part formed in the front part of the piston and sliding on the inner circumferential surface of the cylinder, and a fourth part formed in the rear part of the piston and having the same outer diameter as the outer diameter of the first part,
The first part has a plurality of second parts extending rearward of the first part and having the same outer diameter as the first part, and a pin through hole positioned between the plurality of second parts and into which the piston pin is inserted. machining a third part formed with an outer diameter smaller than the outer diameter of the part and the second part;
machining a fifth part smaller than the outer diameters of the first part and the second part and larger than the outer diameters of the third part to form an intermediate step between the first part and the fourth part; and
and cutting the fourth part and the fifth part from the second part and the third part based on the fifth part. The method of claim 1,
The fifth part is
A method of manufacturing a piston of a reciprocating compressor comprising a groove recessed from an outer circumferential surface of the piston. 3. The method of claim 2,
The fifth part is a method of manufacturing a piston of a reciprocating compressor having a ring shape. 4. The method of claim 3,
On the outer peripheral surface of the piston,
a first inclined portion extending from the front end of the fifth part to the second part; and
and a second inclined portion extending from the rear end of the fifth part to the fourth part. 5. The method of claim 4,
The method for manufacturing a piston of a reciprocating compressor in which the first and second inclined portions extend obliquely outwardly in a radial direction. delete 5. The method of claim 4,
In the step of cutting the fourth part and the fifth part,
and performing cutting using a cutting line extending in a radial direction at a point where the first inclined portion and the fifth part meet. 8. The method of claim 7,
When the cutting of the fourth part and the fifth part is completed,
An end of the first inclined portion forms a rear end of the piston. The method of claim 1,
In the step of processing the second part and the third part,
and supporting the piston on a support and positioning it between first and second rollers to perform centerless grinding. The method of claim 1,
A plurality of the second part is provided, and the plurality of second parts are spaced apart from each other and provided on both sides of the rear surface of the first part. The method of claim 1,
The first and second parts are a method of manufacturing a piston of a reciprocating compressor to form a sliding portion in contact with the inner circumferential surface of the cylinder. delete

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