KR20210028978A - Piston and reciprocation compressor including the same - Google Patents

Abstract

Provided are a piston capable of compressing fluids while reciprocating in interoperation with the rotation of a rotary shaft, and a reciprocating compressor including the same. According to one aspect of the present invention, the piston includes: a body part having a cross section formed into a pipe shape to press the inside of the cylinder through a closed end part and combine the connecting rod through an open end part; a circumference reinforcement part formed as a protruding surface of a circumferential cross section along the entire outer circumference surface of the body part, from the closed end part to a first spot; and an arc reinforcement part formed as a protruding surface of an arc cross section on the outer circumference surface of the body part, from the first spot to the open end part. The arc reinforcement part is formed such that the arc length at the open-end part is relatively shorter than the arc length at the first spot.

Description

Piston and reciprocating compressor including the same TECHNICAL FIELD [PISTON AND RECIPROCATION COMPRESSOR INCLUDING THE SAME}

The present invention relates to a piston and a reciprocating compressor including the same, and more particularly, to a piston for compressing fluid while reciprocating in conjunction with rotation of a rotary shaft, and a reciprocating compressor including the same.

A compressor is a device that increases pressure by compressing gas. The compressor compresses gas, such as a recipro compressor that compresses and discharges gas sucked into a cylinder with a piston, and a scroll compressor that compresses gas by relatively rotating two scrolls.

In the reciprocating compressor, a piston reciprocating inside a cylinder compresses fluid flowing into a bore of a cylinder. A rotation shaft vertically installed for the reciprocating motion of the piston rotates at a predetermined speed, and the piston inside the cylinder also reciprocates in connection therewith.

In the case of such a reciprocating compressor, in order for the piston to effectively compress the fluid flowing into the bore of the cylinder, the airtightness between the inside of the cylinder and the piston must be maintained. In addition, in order for the piston to smoothly reciprocate inside the cylinder, the frictional force between the inside of the cylinder and the piston must be reduced.

Accordingly, a structure capable of simultaneously improving the airtightness and friction between the cylinder and the piston is closely related to the performance improvement of the reciprocating compressor, and related technologies are being actively developed.

In relation to the above compressor, Korean Patent Laid-Open Publication No. 10-2010-0085760 (hereinafter referred to as'priority document 1') discloses a reciprocating compressor.

Specifically, a housing shell forming a closed space, a drive unit provided in the housing shell and providing a driving force, is connected to the rotating shaft of the drive unit, and compresses the refrigerant by reciprocating movement of the piston in the cylinder using the driving force from the drive unit. A compression unit that sucks the refrigerant and a suction/discharge unit that discharges the compressed refrigerant through the reciprocating motion of the compression unit is disclosed in Prior Document 1.

However, the piston of Prior Document 1 is only related to a configuration that prevents the occurrence of dead volume in which the refrigerant remains in the compression space by forming the head inclined, and it is possible to improve the airtightness and friction between the cylinder and the piston at the same time. It is not considered for the existing configuration.

In addition, Korean Patent Laid-Open Publication No. 10-2018-0138073 (hereinafter referred to as “priority document 2”) discloses a piston of a reciprocating compressor and a method of manufacturing the same.

Specifically, a configuration capable of reducing the mass of the piston by removing a portion unnecessary for the sliding action of the piston after processing the piston for forming the sliding portion and the non-sliding portion is disclosed in Prior Document 2.

However, although the piston of Prior Document 2 discloses a configuration capable of reducing friction by removing unnecessary parts while maintaining a certain part airtightness, it is still not efficient with respect to the left and right bending of the piston centered on the piston pin.

As described above, the piston used in the reciprocating compressor has a problem for effectively distributing the load acting from the piston pin and minimizing the bearing area, but there is a limitation in that the conventional reciprocating compressor cannot adequately solve this problem.

An object of the present invention is to solve the above problems of a piston and a reciprocating compressor including the same.

Specifically, an object of the present invention is to optimize the shape of the piston so as to reduce the frictional force between the piston and the cylinder while preventing leakage of refrigerant in the cylinder during the reciprocating motion of the piston.

In addition, it is an object of the present invention to disperse the load acting from the piston pin during the reciprocating motion of the piston, so that more effective reinforcement is made to the part where the piston lateral force acts.

In addition, an object of the present invention is to improve the efficiency of the reciprocating compressor by stabilizing the behavior of the piston against the right and left bending of the piston centered on the piston pin during the reciprocating movement of the piston.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems that are not mentioned will be clearly understood by those of ordinary skill in the technical field to which the present invention belongs from the following description. I will be able to.

In order to achieve the above or other objects, a piston according to an aspect of the present invention and a reciprocating compressor including the same are configured such that a reinforcing portion made of a protruding surface is formed in an optimal shape on an outer circumferential surface of the piston. Specifically, a circumferential reinforcing portion and an arc reinforcing portion are formed on the outer circumferential surface of the piston, and the arc at each point of the circular reinforcing portion is configured to have an optimum required length.

In addition, the piston and the reciprocating compressor including the same according to an aspect of the present invention are configured to form an arc reinforcing part by dividing a part where the piston side force acts and a part that does not. Specifically, the circular reinforcement portion is configured to include a first arc end formed to have a first arc length and a second arc end formed to have a second arc length shorter than the first arc length.

In addition, in the piston and the reciprocating compressor including the same according to an aspect of the present invention, each circular arc end may have a rectangular projected shape on a plane.

In addition, in the piston and the reciprocating compressor including the same according to an aspect of the present invention, at least one of each arc end may have a projected shape on a plane in a trapezoidal shape.

In addition, the piston and the reciprocating compressor including the same according to an aspect of the present invention are configured to stabilize the behavior of the piston against the left and right bending of the piston centered on the piston pin. Specifically, the central axis of the piston pin is configured to be located within the section in which the first arc end is formed.

In addition, in the piston and the reciprocating compressor including the same according to an aspect of the present invention, the circumferential reinforcement portion may be formed by 7 mm or more from the closed end of the piston.

In addition, in the piston and the reciprocating compressor including the same according to an aspect of the present invention, the first arc end may be formed on an arc of 70° or less with respect to the center of the piston.

In addition, in the piston and the reciprocating compressor including the same according to an aspect of the present invention, the first arc end may be formed by 2 mm or more in both directions from the central axis of the piston pin.

In addition, in the piston and the reciprocating compressor including the same according to an aspect of the present invention, the second arc end may be formed on an arc of 30° or more with respect to the center of the piston.

In addition, in the piston and the reciprocating compressor including the same according to an aspect of the present invention, a circumferential reinforcement part, a first arc end, and a second arc end may all be integrally formed.

In addition, in the piston and the reciprocating compressor including the same according to an aspect of the present invention, the first arc end and the second arc end may be formed to be symmetrical about a plane perpendicular to the piston pin, respectively.

The means for solving the technical problems to be achieved in the present invention is not limited to the above-mentioned solutions, and other solutions that are not mentioned are obvious to those of ordinary skill in the art from the following description. It will be understandable.

The effect of the piston and the reciprocating compressor including the same according to the present invention will be described as follows.

According to at least one of the embodiments of the present invention, a circumferential reinforcing portion and an arc reinforcing portion are formed on the outer circumferential surface of the piston, and the arc at each point of the arc reinforcing portion has an optimum required length, so that the refrigerant in the cylinder is It is possible to reduce the frictional force between the piston and the cylinder while preventing leakage.

In addition, according to at least one of the embodiments of the present invention, since the circular reinforcement portion includes a first arc end formed to have a first arc length and a second arc end formed to have a second arc length shorter than the first arc length In the case of the reciprocating movement of the piston, a more effective reinforcement can be made for the part where the piston side force acts.

In addition, according to at least one of the embodiments of the present invention, since each arc end has a projected shape on a plane of a quadrangle, the area of the arc reinforcement portion may be gradually reduced so as to correspond to an optimal required area.

In addition, according to at least one of the embodiments of the present invention, since at least one of each arc end has a projected shape on a plane of a trapezoid, it is possible to minimize an unnecessary portion of the area of the arc reinforcement portion that is gradually reduced.

In addition, according to at least one of the embodiments of the present invention, since the central axis of the piston pin is located within the section in which the first arc end is formed, the movement of the piston against the left and right bending of the piston centered on the piston pin during the reciprocating movement of the piston. Can stabilize

In addition, according to at least one of the embodiments of the present invention, since the circumferential reinforcement portion is formed by 7 mm or more from the closed end of the piston, an optimum circumferential reinforcement portion for preventing refrigerant leakage may be formed.

In addition, according to at least one of the embodiments of the present invention, since the first arc end is formed on an arc of 70° or less with respect to the center of the piston, it is possible to form an optimal arc reinforcement for a portion where the lateral force of the piston acts. .

In addition, according to at least one of the embodiments of the present invention, since the first arc end is formed by 2 mm or more in both directions from the central axis of the piston pin, it is possible to form an optimal arc reinforcement part for the left and right bending of the piston.

In addition, according to at least one of the embodiments of the present invention, since the second arc end is formed on an arc of 30° or more with respect to the center of the piston, it is possible to form an optimal arc reinforcement for reducing friction.

In addition, according to at least one of the embodiments of the present invention, since the circumferential reinforcement portion, the first arc end and the second arc end are all integrally formed, it is possible to secure structural rigidity of the reinforcement portion and to make the piston easier to manufacture. I can do it.

In addition, according to at least one of the embodiments of the present invention, since the first arc end and the second arc end are each formed symmetrically about a plane orthogonal to the piston pin, the pressure applied to the piston is uniformly distributed to provide reinforcement. The reliability can be further improved.

Further scope of the applicability of the present invention will become apparent from the detailed description below. However, since various changes and modifications within the spirit and scope of the present invention can be clearly understood by those skilled in the art, specific embodiments such as the detailed description and preferred embodiments of the present invention should be understood as being given by way of example only.

1 is a cross-sectional view schematically showing a reciprocating compressor according to an embodiment of the present invention.
2 is an exploded perspective view showing a piston and a connecting rod in a reciprocating compressor according to an embodiment of the present invention.
3 is a view showing an example of a piston in the reciprocating compressor according to an embodiment of the present invention.
FIG. 4 is a view in which the motion state of the piston of FIG. 3 is compared with the motion state of the piston of another structure.
5 is a cross-sectional view illustrating an exemplary state in which the first arc end and the second arc end of the arc reinforcement part are formed in the piston of FIG. 3.
6 is a view showing a modification of the piston in the reciprocating compressor according to an embodiment of the present invention.
7 is a view comparing the motion state of the piston of FIG. 6 with the motion state of the piston of another structure.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing the present invention, a description of a function or configuration that is already known will be omitted in order to clarify the gist of the present invention.

1 is a cross-sectional view schematically showing a reciprocating compressor according to an embodiment of the present invention. 2 is an exploded perspective view showing a piston and a connecting rod in a reciprocating compressor according to an embodiment of the present invention.

In the reciprocating compressor 1 (hereinafter referred to as'compressor 1') according to an embodiment of the present invention, the piston 450 reciprocates in association with the rotation of the rotary shaft 410 in the space inside the compressor 1 While it is made to compress the fluid. The fluid described in the embodiments of the present invention may be formed of a gas or gaseous refrigerant.

In the following, first, the components constituting the compressor 1 according to an embodiment of the present invention and the operation of these components will be briefly described, and in this case, a refrigerant will be described as an example of a fluid.

The compressor 1 includes a shell 100, and the shell 100 includes a lower shell 110 and an upper shell 120.

The inside of the shell is sealed with the outside, and the inside of the shell 100 forms an internal space of the compressor 1. In the interior of the shell 100 (inside of the compressor 1), various parts constituting the compressor 1 are provided, and also lubricating oil (oil) is accommodated. Lubricating oil is stored on the lower shell 110 and can circulate inside the shell 100.

The lower shell 110 is made in the shape of a container opened upward, and the upper shell 120 is made in the shape of a container opened downward, and the upper part of the lower shell 110 and the lower part of the upper shell 120 are Combined with each other to form a shell 100 forming a sealed inner space. In an embodiment of the present invention, an upper portion of the lower shell 110 and a lower portion of the upper shell 120 may be coupled to each other to form a sealed inner space.

Legs 130 are coupled to the outer surface of the lower shell 110, and the legs 130 allow the compressor 1 to be fixed at a specific installation position. For example, when the compressor 1 according to the embodiment of the present invention constitutes a refrigerator, the legs 130 are fixed to a frame constituting the refrigerator so that the compressor 1 is fixed at a specific position of the refrigerator.

Two or more legs 130 may be provided, and may be coupled to the bottom surface of the lower shell 110.

A main body is provided inside the shell, and several parts constituting the compressor 1 are coupled to the main body.

The body may be connected to the inner surface of the shell 100 (lower shell 110) through the elastic body 470, and the elastic body 470 may be formed in the form of a coil spring, and may be provided in plural.

The main body 400 may be provided with a motor 420 that generates power for operating the compressor 1. The motor 420 includes a stator 421 and a rotor 422.

In the compressor 1 according to an embodiment of the present invention, the motor 420 may have a form in which the stator 421 is formed relatively outside, and the rotor 422 is formed relatively inside.

In contrast, in the compressor 1 according to another embodiment of the present invention, the motor 420 may be formed in a form in which the stator 421 is formed relatively inside, and the rotor 422 is formed relatively outside. .

A rotation shaft 410 is formed in the center of the rotor 422, and the rotation shaft 410 rotates together with the rotor 422. In the compressor 1 according to the embodiment of the present invention, the rotation shaft 410 may be formed in a vertical direction, and the rotation shaft of the rotation shaft 410 is formed in a vertical direction.

An oil supply passage 412 through which lubricating oil moves is provided inside the rotating shaft 410. In addition, an oil supply unit 490 is provided at one side of the rotation shaft 410, and at least a portion of the oil supply unit 490 may be immersed in the lubricating oil accommodated in the shell 100.

In the embodiment of the present invention, the oil supply unit 490 may be coupled to the lower end of the rotary shaft 410.

As the oil supply unit 490 operates according to the rotation of the rotary shaft 410, the lubricant may move upward along the oil supply passage 412, and the lubricating oil discharged from the oil supply passage 412 is Each part can be supplied.

A crank pin 430 is connected to the upper side of the rotating shaft 410. The crankpin 430 may be located above the motor 420. The crank pin 430 is disposed eccentrically in the rotation shaft of the rotation shaft 410. Accordingly, when the rotation shaft 410 rotates, the crank pin 430 rotates while forming a predetermined rotation radius at a position eccentric from the rotation axis of the rotation shaft 410.

In the compressor 1 according to the embodiment of the present invention, a cylinder 440 having a generally cylindrical shape may be positioned above the motor 420 and disposed in a horizontal direction. The cylinder 440 may be formed integrally with the main body 400, or may be formed separately and then fixedly coupled to the main body 400.

The piston 450 reciprocates in the bore 441 in the cylinder 440 along the longitudinal direction of the cylinder 440 (axial direction of the cylinder 440, anteroposterior direction). In the embodiment of the present invention, the direction in which the piston 450 reciprocates is defined as the front-rear direction.

The connecting rod 460 connects the crank pin 430 and the piston 450. The connecting rod 460 is reciprocally coupled to the crank pin 430 and reciprocally rotated based on the axis in the vertical direction, and is coupled to the piston 450 and reciprocally rotated based on the axis in the vertical direction.

Accordingly, when the rotation shaft 410 is rotated, the crankpin 430 rotates eccentrically and the piston 450 reciprocates in the front-rear direction.

In front of the cylinder 440, a cylinder head 480 is coupled, and a suction chamber 481 through which refrigerant flows into the cylinder 440 and a discharge chamber 482 through which the compressed refrigerant is discharged are provided.

The refrigerant may be compressed by the operation of the compressor 1 according to the embodiment of the present invention made as described above.

3 is a view showing an example of a piston in the reciprocating compressor according to an embodiment of the present invention. FIG. 4 is a view in which the motion state of the piston of FIG. 3 is compared with the motion state of the piston of another structure. 5 is a cross-sectional view illustrating an exemplary state in which the first arc end and the second arc end of the arc reinforcement part are formed in the piston of FIG. 3.

A detailed configuration of the piston 450 according to the present embodiment will be described with reference to FIGS. 3 to 5.

In the reciprocating compressor 1 according to an embodiment of the present invention, the piston 450 includes a body portion 510, a circumferential reinforcement portion 520, and an arc reinforcement portion 530.

The main body 510 has a pipe shape in cross section to pressurize the inside of the cylinder 440 through the closed end E1 and the connecting rod 460 is coupled through the open end E2, and the piston 450 The circumferential reinforcement portion 520 and the arc reinforcement portion 530, which will be described later by configuring the main appearance of, are formed on the outer peripheral surface of the body portion 510, respectively.

In this case, the closed end E1 of the main body 510 may be a left end with reference to FIGS. 1 and 3, and the open end E2 of the main body 510 is based on FIGS. 1 and 3. Therefore, it may be the right end.

The closed end E1 may compress the refrigerant while the piston 450 moves to the left while the refrigerant is introduced into the bore of the cylinder 440. In addition, the small end of the connecting rod 460 is inserted into the open end E2 so that the connecting rod 460 and the piston 450 may be coupled.

When the body portion 510 is formed as described above, it may be desirable that the outer diameter of the body portion 510 is formed to correspond to the inner diameter of the bore of the cylinder 440 to maintain airtightness when the refrigerant is compressed.

However, if the outer diameter of the body portion 510 is substantially the same as the inner diameter of the bore of the cylinder 440 and there is no clearance above a certain level between them, frictional resistance between the piston 450 and the cylinder 440 may be large.

Due to such frictional resistance, the movement of the piston 450 in the cylinder 440 may not be smooth, and as a result, the performance of the reciprocating compressor 1 may be deteriorated. Specifically, among the mechanical losses of the reciprocating compressor 1, the friction loss occurring between the piston 450 and the cylinder 440 accounts for 40% or more of the total loss.

Therefore, the piston 450 needs to be formed so as to simultaneously improve airtightness and friction between the piston 450 and the cylinder 440. Therefore, a circumferential reinforcement portion 520 and an arc reinforcement portion 530 are formed on the outer circumferential surface of the body portion 510.

The circumferential reinforcing portion 520 is a portion formed as a protruding surface of a circumferential cross-section along the entire outer circumferential surface of the body portion 510 from the closed end E1 to the first point P1, and is a first from the closed end E1. The outer diameter of the piston 450 to the point P1 may be extended from the body portion 510.

That is, since the circumferential reinforcing portion 520 is formed to protrude from the body portion 510 from the closed end portion E1 to the first point P1, the overall outer diameter of the piston 450 may be expanded. Accordingly, airtightness between the bore of the piston 450 and the cylinder 440 may be improved from the closed end E1 to the first point P1.

In this case, the first point P1 is an arbitrary point spaced apart from the closed end E1 by a predetermined interval, and may be appropriately selected through experiments and accumulated data in advance.

The circular reinforcement portion 530 is a portion formed as a protruding surface of an arc cross section on the outer circumferential surface of the body portion 510 from the first point P1 to the open end E2, and is not directly related to the airtightness. It can be formed to be structurally reinforced.

That is, as described above, since compression of the refrigerant is mainly performed on the side of the closed end (E1), the influence on the airtightness of the portion on the side of the open end (E2) is relatively small.

Rather, if the outer diameter of the piston 450 at the open end E2 side is too large, it may be disadvantageous by increasing the frictional force with the bore of the cylinder 440. Accordingly, the outer diameter of the piston 450 from the first point P1 to the open end E2 may not be expanded from the main body 510.

However, when the reciprocating compressor 1 is operated, the piston 450 receives a force due to the rotational motion of the rotor 422 and a force due to compression of the refrigerant. Among them, the rotational motion of the rotor 422 receives a force in the lateral direction of the reciprocating motion at the coupling portion between the piston 450 and the connecting rod 460, which may greatly affect the stability of the motion.

Therefore, it is necessary to lower the maximum pressure generated by structural reinforcement for the portion receiving the force in the lateral direction as described above. For example, structural reinforcement can be achieved by increasing the area of the portion receiving the force in the lateral direction so that the maximum pressure is dispersed.

The portion receiving the force in the lateral direction may be a side surface between the upper and lower points that are coupled to the connecting rod 460 by a piston pin 540 or the like as shown in FIG. 2.

Accordingly, by reinforcing the side surfaces between these coupling points with an arc-shaped arc reinforcing portion 530, reinforcement can be achieved with respect to the force received in the lateral direction.

Centering on the structure as described above, in the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, the arc reinforcing part 530 has an arc length at the open end E2 at the first point. It is formed relatively shorter than the arc length in (P1).

That is, the size of the protruding surface of the arc reinforcing portion 530 for reinforcement may be formed to be relatively small toward the open end portion E2 from the first point P1.

As described above, reinforcement for the force received from the piston 450 in the lateral direction is most necessary at the point where it is coupled with the connecting rod 460 by the piston pin 540, etc., and is received in the lateral direction toward the open end (E2). Since the force itself is not large, the need for reinforcement may be relatively low.

Therefore, in this case, reinforcing from the first point (P1) to the open end (E2) with a uniform arc reinforcement portion 530 is not only unnecessary for structural reinforcement, but rather reduces the frictional resistance at the open end (E2). By making it larger, it can be a more disadvantageous structure in terms of performance.

Therefore, it may be desirable to form a relatively small arc length of the arc reinforcement portion 530 in a portion close to the open end portion E2 that does not require structural reinforcement.

In this way, the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment have a circumferential reinforcing portion 520 and an arc reinforcing portion 530 formed on the outer circumferential surface of the piston 450, and arc reinforcing Since the arc at each point of the part 530 has an optimum required length, the friction between the piston 450 and the cylinder 440 is reduced while preventing the refrigerant leakage in the cylinder 440 when the piston 450 reciprocates. I can make it.

In the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, the circular reinforcing portion 530 is from the first point P1 to the second point P2, the outer peripheral surface of the body portion 510 From the first arc end 531 and the second point P2 to the open end E2 formed to have a first arc length L1 on the top, than the first arc length L1 on the outer circumferential surface of the main body 510 It may include a second arc end 533 formed to have a short second arc length L2.

That is, as shown in FIG. 3, a first arc end 531 having a first arc length L1 is formed from the first point P1 to the second point P2, and the second point P2 A second arc end 533 having a second arc length L2 is formed from to the open end E2. And, in this case, the first arc length L1 is made to be relatively longer than the second arc length L2.

In this case, the second point P2 is also an arbitrary point spaced apart from the first point P1 and the open end E2 by a predetermined interval, and may be appropriately selected through experiments and accumulated data in advance.

Therefore, a first arc end 531 is formed to structurally reinforce a portion where reinforcement is required for the force received in the lateral direction, and a second arc end 533 is formed at a portion where the need for structural reinforcement is not large. Only structural reinforcement can be made.

As described above, the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment have a first arc end 531 formed so that the arc reinforcing portion 530 has a first arc length L1 and Since it includes a second arc end 533 formed to have a second arc length L2 shorter than the first arc length L1, the piston 450 lateral force acts on a portion of the piston 450 reciprocating motion. More effective reinforcement can be made.

In the piston 450 and the reciprocating compressor 1 including the piston 450 according to the present embodiment, the first arc end 531 and the second arc end 533 may have a rectangular projected shape on a plane.

That is, as shown in FIG. 3, the first arc end 531 and the second arc end 533 may be formed in a shape in which a rectangular flat plate member is bent along the outer circumferential surface of the body portion 510 and attached thereto.

Accordingly, the arc reinforcing portion 530 may be formed to decrease in a stepwise area in a stepwise manner toward the open end E2.

As described above, in the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, each arc end 531 and 533 has a projected shape on a plane of a quadrangle, so that the arc reinforcing portion 530 The area can be reduced step by step so that the area corresponds to the optimal required area.

The piston 450 and the reciprocating compressor 1 including the same according to the present embodiment further include a piston pin 540 that passes through the main body 510 and is fastened with one end of the connecting rod 460, and the piston The central axis X of the pin 540 may be positioned between the first point P1 and the second point P2.

That is, as shown in FIG. 2, a piston pin 540 penetrating the main body 510 of the piston 450 in the vertical direction is inserted into the small end of the connecting rod 460, so that the piston 450 and the connecting rod ( 460) can be combined.

When combined in this way, the left and right bending of the piston 450 occurs around the piston pin 540, and the larger the bending, the more unstable the piston 450 behaves and the refrigerant leaks. ) Performance may be degraded.

Therefore, it can be said that improving the left and right bending of the piston 450 around the piston pin 540 as described above is a very important task for improving the performance of the reciprocating compressor 1.

In addition, in order to improve the left and right bending of the piston 450, it is necessary to reduce the maximum pressure at the portion where the lateral force of the piston 450 acts, and the maximum pressure due to the lateral force is the central axis of the piston pin 540 (X It can occur in the part close to ).

Accordingly, the central axis (X) of the piston pin 540 is configured to be positioned between the first point (P1) and the second point (P2), and this portion is a first arc end 531 having a relatively large reinforcement area. ), it is possible to disperse the maximum pressure due to the lateral force.

In this regard, the bending of the piston 450 will be described in more detail with reference to FIG. 4.

4(a) shows a motion state for a piston of another structure, and FIG. 4(b) shows a motion state for the piston 450 according to the present embodiment.

First, in the structure shown in FIG. 4A, the minimum oil film thickness between the piston and the cylinder 440 is not uniform at the top and bottom, and the minimum oil film thickness on the upper surface is about 1.25 μm, which is relatively small.

In this case, the minimum oil film thickness means the thickness of the oil filled between the piston and the cylinder 440, and the smaller this value, the more unstable behavior of the piston bends left and right. And, the more the piston is bent left and right, the more refrigerant leaked into the gap, and the performance of the reciprocating compressor 1 deteriorates.

On the other hand, in the structure shown in (b) of FIG. 4, it can be seen that the minimum oil film thickness between the piston 450 and the cylinder 440 appears more uniformly at the top and bottom, and the minimum oil film thickness is also improved as 2.06 μm.

Accordingly, in the state of motion with respect to the piston 450 according to the present embodiment, the stability of the movement of the piston 450 is increased, so that the performance and reliability of the reciprocating compressor 1 may be improved.

As described above, in the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, since the central axis X of the piston pin 540 is located within the section in which the first arc end 531 is formed, During the reciprocating movement of the piston 450, the movement of the piston 450 may be stabilized with respect to the left and right bending of the piston 450 centered on the piston pin 540.

In the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, the first point P1 may be separated from the closed end E1 by 7 mm or more. That is, the width of the circumferential reinforcing portion 520 may be configured to be secured at least 7mm or more.

As described above, in order to secure airtightness between the cylinder 440 and the piston 450 through the circumferential reinforcing part 520, the circumferential reinforcing part 520 needs to be formed to have a minimum width.

Accordingly, the width of the circumferential reinforcing part 520 needs to be secured at least 7 mm, and if the width is less than that, the amount of refrigerant leakage may increase, and the performance of the reciprocating compressor 1 may be deteriorated.

As described above, in the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, since the circumferential reinforcing portion 520 is formed by 7 mm or more from the closed end E1 of the piston 450, the refrigerant leakage is prevented. It is possible to form an optimal circumferential reinforcement portion 520 for.

In the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, the first arc end 531 may be formed on an arc of 70° or less with respect to the center of the body portion 510.

That is, as shown in FIG. 5, an angle between the upper and lower ends of the first arc end 531 and the center of the body portion 510 may be formed to be 70° or less.

As described above, in order to perform structural reinforcement through the first arc end 531, it may be advantageous to have the first arc end 531 largely formed. However, when the first arc end 531 is formed too large, even if structural reinforcement is performed, frictional resistance is largely generated, and the performance of the reciprocating compressor 1 may be rather deteriorated.

Accordingly, the first arc end 531 needs to be formed to be limited to 70° or less with respect to the center of the body portion 510.

As described above, in the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, since the first arc end 531 is formed on an arc of 70° or less with respect to the center of the piston 450, It is possible to form an optimal arc reinforcement portion 530 for a portion where the piston 450 lateral force acts.

In the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, the first point P1 and the second point P2 are 2 mm or more from the central axis X of the piston pin 540, respectively. Can be separated.

That is, the width of the first arc end 531 may be configured to be at least 2mm or more secured on both sides from the central axis X of the piston pin 540.

As described above, in order to distribute the maximum pressure due to the lateral force through the first arc end 531, the central axis X of the piston pin 540 must be located within the first arc end 531, and the first arc end 531 Since the arc end 531 is formed to have a minimum width or more, the central axis X of the piston pin 540 needs to be stably positioned within the first arc end 531.

Accordingly, the width of the first arc end 531 needs to be secured at least 2mm on both sides from the central axis X of the piston pin 540, and when formed with a width less than that, the piston 450 lateral force effectively It may not be possible to reinforce the affected area.

As described above, in the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, since the first arc end 531 is formed by 2 mm or more in both directions from the central axis X of the piston pin 540 , It is possible to form an optimal arc reinforcement portion 530 for the left and right bending of the piston 450.

In the piston 450 and the reciprocating compressor 1 including the piston 450 according to the present embodiment, the second arc end 533 may be formed on an arc of 30° or more with respect to the center of the body portion 510.

That is, as illustrated in FIG. 5, an angle between the upper and lower ends of the second arc end 533 and the center of the body portion 510 may be formed to be 30° or more.

As described above, it may be advantageous that the second arc end 533 is formed small in order to minimize frictional resistance. However, when the second arc end 533 is formed too small, the open end E2 side becomes a structurally weak point, and thus the performance of the piston 450 and the reciprocating compressor 1 including the piston 450 may be deteriorated.

Accordingly, the second arc end 533 needs to be formed to have a minimum size of 30° or more with respect to the center of the body portion 510.

As described above, in the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, since the second arc end 533 is formed on an arc of 30° or more with respect to the center of the piston 450, friction It is possible to form an optimal arc reinforcement portion 530 for reduction.

In the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, the circumferential reinforcing portion 520, the first arc end 531, and the second arc end 533 may all be integrally formed. have.

That is, as shown in FIG. 3, the circumferential reinforcement part 520, the first arc end 531, and the second arc end 533 may be formed by processing one member differently only in size from each other. In this case, the circumferential reinforcement portion 520, the first arc end 531, and the second arc end 533 are formed by processing the body portion 510, so that it is further formed integrally with the body portion 510. It may be desirable.

For example, the circumferential reinforcement portion 520, the first arc end 531, and the second arc end 533 may be formed by cutting the outer circumferential surface of the body portion 510 or the like. Alternatively, after processing one plate-like member to correspond to the area of the circumferential reinforcing part 520, the first arc end 531, and the second arc end 533, it is bent and attached to the outer circumferential surface of the body part 510 I can make it.

Through this, there is no cut surface between the circumferential reinforcement portion 520, the first arc end 531 and the second arc end 533, so that rigidity against shearing force, etc. can be secured, as well as the processing process Can be further simplified.

In this way, the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, the circumferential reinforcing portion 520, the first arc end 531 and the second arc end 533 are all integrally Since it is formed, not only can the structural rigidity of the reinforcing portion be secured, but also the manufacture of the piston 450 can be made easier.

In the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, the first arc end 531 and the second arc end 533 are respectively centered on a plane perpendicular to the piston pin 540. It can be formed symmetrically.

That is, as shown in FIG. 3, the first arc end 531 and the second arc end 533 may be formed to be vertically symmetric about a horizontal plane.

As described above, in order to secure the stability of the movement of the piston 450, it is necessary to ensure that the minimum oil film thickness between the upper and lower surfaces of the piston 450 and the cylinder 440 is uniformly secured. Therefore, it is necessary to form the arc reinforcing portion 530 so as to be uniformly reinforced against external forces such as lateral forces applied to the upper and lower surfaces of the piston 450.

As described above, in the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, the first arc end 531 and the second arc end 533 are respectively perpendicular to the piston pin 540 Since it is formed to be symmetrical around, it is possible to further improve the reliability of reinforcement by uniformly distributing the pressure applied to the piston 450.

6 is a view showing a modification of the piston in the reciprocating compressor according to an embodiment of the present invention. 7 is a view comparing the motion state of the piston of FIG. 6 with the motion state of the piston of another structure.

A detailed configuration of a modification example of the piston 450 according to the present embodiment will be described with reference to FIGS. 6 and 7.

In the piston 450 according to the present embodiment and the reciprocating compressor 1 including the same, at least one of the first arc end 531 and the second arc end 533 may have a projection shape on a plane formed in a trapezoidal shape. have.

That is, as shown in FIG. 6, at least one of the first arc end 531 and the second arc end 533 is formed in a shape in which a trapezoidal plate member is bent and attached along the outer circumferential surface of the body part 510. I can.

In this case, in FIG. 6, only the second arc end 533 is formed through the trapezoidal member, but is not limited thereto, and only the first arc end 531 is formed through the trapezoidal member or the first arc Both the end 531 and the second arc end 533 may be formed through a trapezoidal member.

As described above, the need for reinforcement may be relatively lowered toward the open end E2. In particular, the need for reinforcement is lower for each corner portion of the circular arc reinforcing portion 530 formed in a square shape, and rather, it is necessary to minimize the area of each corner to reduce frictional resistance.

Accordingly, forming the first arc end 531 and the second arc end 533 in a trapezoid shape may be the best form in terms of structural reinforcement and frictional resistance improvement.

As described above, in the piston 450 and the reciprocating compressor 1 including the same according to the present embodiment, at least one of the arc ends 531 and 533 is formed in a trapezoidal projected shape on a plane, so that it is gradually reduced. It is possible to minimize unnecessary parts of the area of the arc reinforcing part 530.

In this regard, the bending of the piston 450 will be described in more detail with reference to FIG. 7.

7(a) shows a motion state for a piston of another structure, and FIG. 7(b) shows a motion state for the piston 450 according to the present embodiment.

First, since (a) of FIG. 7 has been described in (a) of FIG. 4 above, detailed descriptions of overlapping contents will be omitted.

In addition, in the structure shown in (b) of FIG. 7, it can be seen that the minimum oil film thickness between the piston 450 and the cylinder 440 appears more uniformly at the top and bottom, and the minimum oil film thickness is also improved as 2.54 μm.

Accordingly, in the state of motion with respect to the piston 450 according to the present embodiment, the stability of the movement of the piston 450 is increased, so that the performance and reliability of the reciprocating compressor 1 may be further improved.

In the above, although specific embodiments of the present invention have been described and illustrated, the present invention is not limited to the described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. It is self-evident to those who have Therefore, such modifications or variations should not be individually understood from the technical spirit or point of view of the present invention, and the modified embodiments should be said to belong to the claims of the present invention.

1: reciprocating compressor 100: shell
110: lower shell 120: upper shell
130: leg 410: rotating shaft
412: oil supply passage 420: motor
421: stator 422: rotor
430: crankpin 440: cylinder
450: piston 460: connecting rod
480: cylinder head 481: suction chamber
482: discharge chamber 490: oil supply unit
510: main body 520: circumferential reinforcement
530: circular reinforcement part 531: first circular end
533: second circular end 540: piston pin
E1: closed end E2: open end
L1: first arc length L2: second arc length
P1: first point P2: second point
X: central axis of the piston pin

Claims (14)

In the piston inserted into the cylinder in a state coupled to the connecting rod to reciprocate the inside of the cylinder by the driving force transmitted from the connecting rod,
A body portion having a pipe shape in cross section to pressurize the inside of the cylinder through a closed end and to which the connecting rod is coupled through an open end;
A circumferential reinforcing portion formed as a protruding surface of a circumferential cross section along the entire outer circumferential surface of the main body from the closed end to the first point; And
An arc reinforcing part formed as a protruding surface of an arc cross section on an outer circumferential surface of the main body from the first point to the open end;
Including,
The arc reinforcing portion, the arc length at the open end is formed relatively shorter than the arc length at the first point, the piston. The method of claim 1,
The circular reinforcement part
From the first point to the second point, a first arc end formed to have a first arc length on the outer circumferential surface of the body portion, and
A piston comprising a second arc end formed to have a second arc length shorter than the first arc length on an outer circumferential surface of the body portion from the second point to the open end. The method of claim 2,
The first arc end and the second arc end are formed in a rectangular projected shape on a plane, the piston. The method of claim 3,
At least one of the first arc end and the second arc end is formed in a trapezoidal projection shape on a plane, the piston. The method of claim 2,
A piston pin penetrating the main body and fastened with one end of the connecting rod;
Including more,
The piston, wherein the central axis of the piston pin is located between the first point and the second point. The method of claim 5,
The first point is a piston spaced apart by 7 mm or more from the closed end. The method of claim 6,
The first arc end is formed on an arc of 70° or less with respect to the center of the body portion, the piston. The method of claim 7,
The first point and the second point are each spaced apart by 2 mm or more from the central axis of the piston pin, the piston. The method of claim 8,
The second arc end is formed on an arc of 30° or more with respect to the center of the body part, the piston. The method of claim 2,
The circumferential reinforcing portion, the first arc end and the second arc end are all integrally formed, the piston. The method of claim 5,
The first arc end and the second arc end are each formed to be symmetrical about a plane perpendicular to the piston pin, the piston. A shell forming an enclosed space and receiving lubricating oil therein;
A rotating shaft rotatably installed inside the shell;
A motor that rotates the rotation shaft about a central axis;
A crank pin positioned on the upper side of the motor and eccentrically disposed on the rotation shaft to rotate;
A cylinder positioned above the motor and disposed in a horizontal direction;
A piston reciprocating within the cylinder; And
Including; a connecting rod connecting the crank pin and the piston,
The piston
A body portion having a cross section formed in a pipe shape to pressurize the inside of the cylinder through a closed end and to which the connecting rod is coupled through an open end,
From the closed end to the first point, a circumferential reinforcing portion formed as a protruding surface of a circumferential cross section along the entire outer circumferential surface of the main body; and
From the first point to the open end, including an arc reinforcement portion formed as a protruding surface of an arc cross section on the outer circumferential surface of the main body,
The arc reinforcing portion is formed in a relatively shorter arc length than the arc length at the first point at the open end, the reciprocating compressor. The method of claim 12,
The circular reinforcement part
From the first point to the second point, a first arc end formed to have a first arc length on the outer circumferential surface of the body portion, and
A reciprocating compressor comprising a second arc end formed to have a second arc length shorter than the first arc length on an outer circumferential surface of the main body from the second point to the open end. The method of claim 12,
The piston
Further comprising a piston pin through the body portion and fastened with one end of the connecting rod,
The reciprocating compressor, wherein the central axis of the piston pin is located between the first point and the second point.

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