WO2009051371A2

WO2009051371A2 - Reciprocompressor

Info

Publication number: WO2009051371A2
Application number: PCT/KR2008/005946
Authority: WO
Inventors: Bok-Ann Park; Dong-Woo Park; Phil-Ho Cho
Original assignee: Lg Electronics Inc.
Priority date: 2007-10-19
Filing date: 2008-10-09
Publication date: 2009-04-23
Also published as: CN102171456B; WO2009051371A3; CN102171456A

Abstract

Disclosed is a reciprocating compressor which can prevent a deformation of a sleeve, when the sleeve is to be fixed to a connecting rod, by fixing the sleeve using a separate fixing member elastically coupled to the connecting rod, and accordingly, the sleeve may smoothly perform a sliding-rotation with respect to a eccentric portion of the crank shaft, thus to enhance compressor efficiency by preventing abrasion between a piston and a cylinder block.

Description

RECIPROCOMPRESSOR

TECHNICAL FIELD

The present invention relates to a reciprocating compressor in which a piston performs a linear motion by receiving a rotation force from a driving motor.

BACKGROUND ART

In general, a reciprocating compressor serves to suck, compress and discharge a refrigerant as a piston performs a linear reciprocating motion in a cylinder. The reciprocating compressor may be divided into a linear type and a rotary type according to the type of a driving motor. The linear type reciprocating compressor adopts a linear motor and uses a mechanism for a mover of a motor to perform a linear reciprocating motion. The rotary type reciprocating compressor adopts a rotary motor and uses a mechanism for converting a rotation force of the driving motor into a linear motion.

For instance, the reciprocating compressor implementing the rotary type driving motor uses a connecting rod for connecting between a crank shaft of the driving motor and the piston, and converts a rotation force of the driving motor into a linear motion of the piston. For this, a sleeve is interposed between an eccentric portion of the crank shaft and the connecting rod, and thusly the connecting rod may perform forward/rearward movements while smoothly performing a sliding-rotation with respect to the crank shaft. An outer circumferential surface of the sleeve is pressingly inserted into the connecting rod, and an inner circumferential surface thereof performs a slide motion while forming a bearing surface together with the eccentric portion of the crank shaft.

The sleeve of the conventional reciprocating compressor is configured to be pressingly inserted and thereby fixed into the connecting rod. However, during or after the insertion process of the sleeve, the sleeve may be pressed by the connecting rod and thus to cause a deformation of the inner circumferential surface thereof. Thusly, the sleeve cannot smoothly perform the slide motion with the eccentric portion of the crank shaft, thereby reducing compressor efficiency.

DISCLOSURE OF THE INVENTION

Therefore, it is an object of the present invention to provide a reciprocating compressor which can enhance compressor efficiency by preventing a deformation of a sleeve when the sleeve is coupled to a connecting rod. To achieve this and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a reciprocating compressor, including: a driving motor; a connecting rod eccentrically coupled to a crank shaft of the driving motor and converting a rotation motion of the driving motor into a linear motion; a piston coupled to the connecting rod and compressing a refrigerant while performing a linear reciprocating motion in a cylinder; a sleeve inserted into the connecting rod and performing a sliding-rotation with respect to an eccentric portion of the crank shaft; and a fixing member coupled to the connecting rod and fixing the sleeve to the connecting rod. EFFECT

The reciprocating compressor according to the present invention may prevent a deformation of a sleeve as the sleeve is fixed by using a separate fixing member without being pressingly inserted into a connecting rod. Accordingly, the sleeve may smoothly perform a sliding-rotation with respect to an eccentric portion of a crank shaft, thus to enhance compressor efficiency by preventing abrasion between a piston and a cylinder block.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a longitudinal cross-sectional view showing an exemplary reciprocating compressor according to the present invention;

Figure 2 is an exploded perspective view showing a fixing device of a sleeve in the reciprocating compressor in Fig. 1 ;

Figure 3 is a longitudinal cross-sectional view showing an assembled state of the fixing device of the sleeve in Fig. 2;

Figure 4 is a plane view showing the assembled state of the fixing device of the sleeve in Fig. 2;

Figures 5 and 6 are longitudinal cross-sectional views each showing that a fixing groove is formed at the sleeve in the reciprocating compressor in Fig. 1 ;

Figure 7 is an exploded perspective view showing another exemplary fixing device of the sleeve in the reciprocating compressor in Fig. 1 ;

Figure 8 is a longitudinal cross-sectional view showing an assembled state of the fixing device of the sleeve in Fig. 7; Figure 9 is a plane view showing the assembled state of the fixing device of the sleeve in Fig. 7; and Figure 10 is a longitudinal cross-sectional view showing that the fixing groove is formed at the sleeve in the reciprocating compressor in Fig. 7.

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS Reference will now be given in detail of the reciprocating compressor according to the present invention, examples of which are illustrated in the accompanying drawings.

As shown in Fig. 1 , the reciprocating compressor according to the present invention may include a casing 1 having a hermetic inner space therein, a driving motor 10 mounted inside the casing 1 and generating a rotation force by power supplied from an external source, and a compression part 20 coupled to a crank shaft 13 of the driving motor 10 inside the casing 1 and receiving the rotation force of the driving motor 10 so as to suck and compress a refrigerant. The driving motor 10 is comprised of a stator 11 installed inside the casing 1 so as to be elastically supported, a rotor 12 rotatably installed inside the stator 11 , and the crank shaft 13 fixed to the rotor 12 and transferring the rotation force of the rotor 12 to the compression part 20.

The compression part 20 may include a cylinder block 21 horizontally disposed inside the casing 1 and forming a compression space (no reference numeral) at one side thereof in a radial direction, a sleeve 22 rotatably inserted into an eccentric portion 13a of the crank shaft 13 placed on a front surface of the cylinder block 21 , a connecting rod 23 coupled to an outer circumferential surface of the sleeve 22 and converting a rotation motion of the crank shaft 13 into a reciprocating motion of the piston 24 as will be described later, the piston 24 coupled to another end of the connecting rod 23 and performing the reciprocating motion in a radial direction of the crank shaft 13 inside the compression space of the cylinder block 21 , and a valve assembly 25 installed at a discharge side of the cylinder block 21 and controlling suction/discharge of a refrigerant. And, the compression part 20 further includes a discharge cover 26 installed at one side of the cylinder block 21 and fixed to the valve assembly 25 with a prescribed discharge space (no reference numeral), a suction muffler 27 coupled to the discharge cover 26 so as to be communicated with a suction side of the valve assembly 25, and a discharge muffler 28 mounted at the cylinder block 21 so as to be communicated with a discharge side of the valve assembly 25 through the discharge cover 27.

Here, the sleeve 22 is inserted into the connecting rod 23, and a fixing member 31 for fixing the sleeve 22 to the connecting rod 23 is installed between the sleeve 22 and the connecting rod 23. Referring to Figs. 2 and 3, the sleeve 22 is formed to have a cylindrical shape having a certain diameter, and a connecting portion 23a for inserting the sleeve 22 thereinto is formed in a circular band shape at one side of the connecting rod 23. Preferably, an outer diameter of the sleeve 22 is formed to be smaller than or approximately equal to an inner diameter of the connecting portion 23a of the connecting rod 23 such that the sleeve 22 is smoothly inserted into the connecting portion 23a of the connecting rod 23. As shown in Fig. 4, preferably, an inner diameter D1 of the fixing member 31 is formed to be smaller than or equal to an outer diameter D2 of the sleeve 22 such that a portion of the inner circumferential surface of the fixing member 31 tightly contacts a portion of the outer circumferential surface of the sleeve 22.

The outer circumferential surface of the sleeve 22 may be formed to be smooth. In some cases, a fixing groove 22a having an arc shape along a circumferential direction, as shown in Fig. 6, may be formed on the outer circumferential surface of the sleeve 22 such that both ends of the fixing member 31 are inserted onto the outer circumferential surface thereof and thereby to restrict the sleeve 22 in a shaft direction.

The fixing member 31 is formed to have a horseshoe shape or an arc shape of a letter "C" such that the inner circumferential surface of the fixing member 31 partially or entirely contacts the outer circumferential surface of the sleeve 22 and thereby to fix the sleeve 22 to the connecting rod 23. A distance L1 between both ends of the fixing member 31 may be formed to be larger than or equal to the outer diameter D2 of the sleeve 22 such that the fixing member 31 is inserted onto the outer circumferential surface of the sleeve 22 in a radial direction. The distance L1 between both ends of the fixing member 31 may also be formed smaller than the outer diameter D2 of the sleeve 22 if the fixing member 31 is formed of an elastic material capable of being shrunk in a certain degree or a groove is formed on the outer circumferential surface of the sleeve 22.

The fixing member 31 is fixed on the upper surface of the connecting portion 23a of the connecting rod 23. For this, as shown in Fig. 3, a coupling hole 23b formed on the upper surface of the connecting portion 23a of the connecting rod 23 and a through-hole 31a formed at the fixing member 31 may be coupled by a bolt 32. Alternatively, as shown in Fig. 5, a through-hole 23c formed at the connecting portion 23a of the connecting rod 23 and a through-hole 31a formed at the fixing member 31 may be coupled by a rivet 33.

Meanwhile, as shown in Fig. 6, a circular band-shaped fixing groove 22a may be concavely formed on the outer circumferential surface of the sleeve 22, so that the fixing member 31 is inserted thereto and thereby an upper end of the inner circumferential surface of the fixing member 31 is fixed to the sleeve 22 by being locked in a shaft direction. The reciprocating compressor according to the present invention has the following operational effects.

If power is applied to the driving motor 10, the crank shaft 13 is rotated by an interacting force of the stator 11 and the rotor 12. As the connecting rod 23, inserted into the eccentric portion 13a of the crank shaft 13 together with the sleeve 22, performs a linear motion while performing an orbiting motion, the piston 24 performs a reciprocating motion in the compression space of the cylinder block 21. By such reciprocating motion of the piston 24, the refrigerant is sucked into the compression space of the cylinder block 21 through the suction muffler 27 and the suction valve (not shown) of the valve assembly 25, and then is sequentially discharged from the discharge cover 26 and the discharge muffler 28 through the discharge valve (not shown) of the valve assembly 25. The above processes are repeated.

Here, during the sleeve 22 is forcibly inserted and fixed to the connecting portion 23a of the connecting rod 23, the sleeve 22 may be deformed, thereby causing the inner circumferential surface of the sleeve 22 to have an increasing friction loss with the outer circumferential surface of the eccentric portion 13a of the crank shaft 13. However, according to the present invention, if the outer diameter D2 of the sleeve 22 is formed to be less than or equal to the inner diameter D1 of the connecting portion 23a of the connecting rod 23, and if the fixing member 31 being assembled into the connecting rod 23 is used to fix the sleeve 22, deformation of the sleeve 22 can be prevented when the sleeve 22 is inserted into the connecting portion 23a of the connecting rod 23. And accordingly, as the sleeve 22 smoothly performs the sliding-rotation with respect to the eccentric portion 13a of the crank shaft 13, abrasion between the piston 24 and the cylinder block 21 can be prevented, thereby increasing the compressor efficiency.

Another exemplary fixing member for fixing the sleeve of the reciprocating compressor according to the present invention to the connecting rod will be described.

That is, in the previous embodiment, the fixing member is formed in a plate shape having the arc shape, and is coupled to the connecting rod using a bolt, etc., under the state that the inner circumferential surface of the fixing member tightly contacts the outer circumferential surface of the sleeve. However, in this embodiment, the fixing member is formed as a linear member so as to be elastically fixed to the connecting rod. Referring to Figs. 7 through 9, an outer circumferential surface of the sleeve 122 is formed to be smooth, and a first fixing groove 122a may be formed to have a stepped portion such that both ends of a third fixing portion 131c of a fixing member 131 , as will be described later, are locked by a lower end of the sleeve 122 and thereby to support the sleeve 122 in a shaft direction. In addition, as shown in Fig. 10, a second fixing groove 122b formed in an arc shape may be formed in along a circumferential direction such that, instead of the first fixing groove 122a, a first fixing portion 131a of the fixing member 131 , which will be described later, is inserted onto an outer circumferential surface of the sleeve 122 and thereby to restrict the sleeve 122 in the shaft direction. Here, as shown in Figs. 8 and 10, one of the first fixing groove 122a and the second fixing groove 122b may be formed at the sleeve 122, or the first and second fixing grooves 122a and 122b may respectively be formed at the lower and upper ends of the sleeve 122.

As described above, the fixing member 131 uses the linear member to surround and fix the outer circumferential surface of the sleeve 122, and simultaneously, both ends of the fixing member 131 are inserted into the connecting rod 123. For this, the first fixing portion 131a for surrounding the outer circumferential surface of the sleeve 122 is formed at one side of the fixing member 131 , and the second fixing portion 131 b for fixing the fixing member 131 to the connecting rod 123 is formed by being curved at both ends of the first fixing portion 131a in the shaft direction and inserted into a supporting groove 123b penetratingly formed at a periphery of the connecting portion 123a of the connecting rod 123. The second fixing portion 131 b is inserted into the supporting groove and thereby to restrict a force of the first fixing portion 131a to be widened toward the circumferential direction, thereby enabling the first fixing portion 131a to tighten and fix the sleeve 122. And, the fixing member 131 includes a third fixing portion 131c bent from each end of the second fixing portion 131 b in the radial direction and having both ends thereof locked by the first fixing groove 122a of the sleeve 122, thereby supporting the sleeve 122 in the shaft direction. The operational effect of the reciprocating compressor according to this exemplary embodiment of the present invention is almost the same as that in the previous exemplary embodiment. However, in this embodiment, the fixing member 131 formed in the linear member is configured to be fixed by being locked into the connecting rod 123. Accordingly, there is no need to use an additional coupling member during the assembly process of the fixing member 131 into the connecting rod 123, thereby reducing the number of components, thus to simplify the assembly process and reduce a production cost.

Industrial applicability The reciprocating compressor according to the present invention may be applied to a cooling cycle apparatus such as a refrigerator, an air conditioner, and the like.

It will also be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

1. A reciprocating compressor, comprising: a driving motor; a connecting rod eccentrically coupled to a crank shaft of the driving motor and converting a rotation motion of the driving motor into a linear motion; a piston coupled to the connecting rod and compressing a refrigerant while performing a linear reciprocating motion in a cylinder; a sleeve inserted into the connecting rod and performing a sliding-rotation with respect to an eccentric portion of the crank shaft; and a fixing member coupled to the connecting rod and fixing the sleeve to the connecting rod.

2. The reciprocating compressor of claim 1 , wherein the fixing member formed in an arc shape has both ends.

3. The reciprocating compressor of claim 2, wherein the fixing member is configured such that its inner diameter is formed to be equal to or less than an outer diameter of the sleeve.

4. The reciprocating compressor of claim 2, wherein a distance between both ends of the fixing member is formed to be equal to or less than the outer diameter of the sleeve.

5. The reciprocating compressor of claim 4, wherein a fixing groove is formed at the sleeve such that both ends ot tne Tixing member are inserted onto an outer circumferential surface of the sleeve.

6. The reciprocating compressor of claim 4, wherein the fixing member is formed of a material having elasticity in a contracted direction.

7. The reciprocating compressor of claim 2, wherein a distance between both ends of the fixing member is formed greater than an outer diameter of the sleeve.

8. The reciprocating compressor of claim 1 , wherein the fixing member is fixed to the connecting rod by a bolt or a rivet.

9. The reciprocating compressor of claim 1 , wherein the fixing member is formed in a linear member.

10. The reciprocating compressor of claim 9, wherein a first fixing portion for surrounding and fixing the sleeve is formed at one side of the fixing member, and a second fixing portion extending from the first fixing portion is formed at one side of the first fixing portion such that the fixing member is supported by the connecting rod.

11. The reciprocating compressor of claim 10, wherein the first fixing portion is configured such that its inner circumferential surface can contact an outer circumferential surface of the sleeve by 3^ or more.

12. The reciprocating compressor of claim 10, wherein the second fixing portion is formed to have both ends such that said both ends are widened in a circumferential direction of the connecting rod.

13. The reciprocating compressor of claim 10, wherein the connecting rod is provided with a supporting groove for receiving the second fixing portion and supporting both ends thereof by widening said both ends to the circumferential direction of the connecting rod.

14. The reciprocating compressor of claim 10, wherein a third fixing portion for supporting the sleeve in a shaft direction is further provided at an end of the second fixing portion.

15. The reciprocating compressor of claim 14, wherein the sleeve is further provided with a fixing groove for locking the third fixing portion of the fixing member.

16. The reciprocating compressor of claim 1 , wherein the fixing member is configured such that its inner circumferential surface closely contacts at least one position on an outer circumferential surface of the sleeve.

17. The reciprocating compressor of claim 1 , wherein at least one fixing groove is formed on the outer circumferential surface of the sleeve in the circumferential direction such that the fixing member is inserted into the fixing groove.