Hermetic compressor

Abstract

Disclosed is a hermetic compressor capable of preventing an intake valve from making contact with a piston without reducing compressing efficiency of the compressor. The hermetic compressor includes a cylinder block having a compressing chamber, a piston performing a reciprocation, a cylinder block coupled at an side of the cylinder block so as to close the compressing chamber and an intake valve plate which is provided between the cylinder block and the cylinder head and has an intake valve which controls a flow of a refrigerant introduced into the compressing chamber, wherein a compressing surface of the piston facing the intake valve plate forms a flat surface parallel to the intake valve plate and an anti-contact portion which receives a part of the intake valve is formed on the compressing surface so as to prevent the piston from making contact with the intake valve during the reciprocation of the piston.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 2006-32423 filed on Apr. 10, 2006, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hermetic compressor, and more particularly to a hermetic compressor capable of preventing an intake valve from making contact with a piston without reducing the compressing efficiency of the compressor.

2. Description of the Prior Art

A hermetic compressor has been widely used in a refrigerating cycle for a refrigerator or an air conditioner. Such a hermetic compressor includes a closed casing forming an external appearance, a compressing unit which is provided in the closed casing to compress refrigerant and a driving unit which provides the compressing unit with driving force.

Among these components, the compressing unit includes a cylinder block forming a compressing chamber in which the refrigerant is compressed, a piston performing a linear reciprocation in the compressing chamber so as to compress the refrigerant, a cylinder head coupled to one side of the cylinder block so as to close the compressing chamber and provided with an intake chamber and an exhaust chamber that are separated from each other, and a valve unit which is provided between the cylinder block and the cylinder head so as to control the flow of the refrigerant which is introduced into the compressing chamber from the intake chamber or is exhausted from the compressing chamber into an exhaust chamber.

Under this configuration, if the driving unit is operated, the piston performs the linear reciprocation in the compressing chamber so that the refrigerant provided at an outer portion of the closed casing is introduced into the intake chamber of the cylinder head, and then is transferred to the compressing chamber so that the refrigerant is compressed in the compressing chamber. In this manner, the refrigerant compressed in the compressing chamber is exhausted into the exhaust chamber of the cylinder head and then is exhausted out of the closed casing through an exhaust tube. Such a process is repeated, so that the refrigerant is compressed by means of the compressor.

The valve unit includes a valve plate having an intake hole and an exhaust hole through which the compressing chamber is communicated with the intake chamber and the exhaust chamber, an intake valve which opens/closes the intake hole and an exhaust valve assembly which opens/closes the exhaust hole.

the intake valve is designed to be easily opened according to the movement of the piston during an intake process of such a hermetic compressor. In order to allow the intake valve to be easily opened, the intake valve is designed to be easily bent according to pressure variation in the compressing chamber.

Since the intake valve is designed to be easily bent according to the pressure variation in the compressing chamber, if the intake vlave is excessively bent relative to the moving distance of the piston when the piston moves from the top dead point to the bottom dead point, the intake valve makes contact with a surface of the piston. If the intake valve makes contact with the piston, the intake valve or the piston may be broken, degrading the reliability of the product. In addition, if debris derived from the breakage remains in the compressing chamber, the cylinder block may be worn.

In this manner, in order to prevent the intake valve from making contact with the piston, a gasket having a large thickness is interposed between the piston and the intake valve. However, if the thickness of the gasket is too large, a dead volume is increased between the piston and the intake valve, degrading the compressing efficiency of the compressor.

SUMMARY OF THE INVENTION

The present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a hermetic compressor capable of preventing an intake valve from making contact with a piston without reducing the compressing efficiency of the compressor.

In order to accomplish the above object, according to an aspect of the present invention, there is provided a hermetic compressor comprising a cylinder block having a compressing chamber, a piston performing a reciprocation in the compressing chamber, a cylinder head which is coupled to one side of the cylinder block so as to close the compressing chamber and an intake valve plate having an intake valve which is provided between the cylinder block and the cylinder head so as to control a flow of a refrigerant which is introduced into the compressing chamber, wherein a compressing surface of the piston facing the intake valve plate forms a flat surface parallel to the intake valve plate, and an anti-contact portion which receives a part of the intake valve is formed on the compressing surface so as to prevent the piston from making contact with the intake valve during the reciprocation of the piston.

The anti-contact portion includes a recess having a shape corresponding to a shape of the intake valve.

The anti-contact portion has a width larger than a width of the intake valve so that the intake valve passes through the anti-contact portion.

The intake valve is formed by cutting the intake valve plate, in which one end of the intake valve serves as a fixing end and the other end of the intake valve serves as a free end.

A depth of the anti-contact portion gradually increases from the fixing end to the free end.

A volume of the anti-contact portion is set within a predetermined range which does not reduce a compressing efficiency of the hermetic compressor.

A volume of the anti-contact portion is set within a predetermined range which does not reduce a compressing efficiency of the hermetic compressor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view representing a hermetic compressor according to an embodiment of the present invention;

FIG. 2 is an exploded perspective view representing a valve unit and a piston shown in FIG. 1;

FIG. 3 is a sectional view representing a piston when the piston shown in FIG. 2 reaches a top dead point; and

FIG. 4 is a sectional view representing an operation of an intake valve when the piston moves back from the top dead point.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a hermetic compressor according to a preferred embodiment of the present invention will be explained in detail with reference to the accompanying drawings.

A hermetic compressor according to an embodiment of the present invention is as shown in FIG. 1 includes a closed casing 1 in which a top casing 1a and a bottom casing 1b are coupled with each other, a compressing unit 10 which is provided in the closed casing 1 to compress refrigerant and a driving unit 20 which provides the compressing unit 10 with driving force. An intake tube 2 which guides the refrigerant from an exterior into the closed casing 1 is provided at one side of the closed casing 1 and an exhaust tube 3 which exhausts the compressed refrigerant in the compressed unit 10 into the outside of the closed casing 1 is provided at the other side of the closed casing 1.

Among these components, the compressing unit 10 includes a cylinder block 11 which has a compressing chamber 11a for compressing the refrigerant, a piston 12 which compresses the refrigerant while performing a linear reciprocation in the compressing chamber 11a, a cylinder head 13 which is coupled to one side of the cylinder block 11 to close the compressing chamber 11a and has an intake chamber 13aand an exhaust chamber 13b that are separated from each other, and a valve unit 30 which is provided between the cylinder block 11 and the cylinder head 13 and controls a flow of the refrigerant which is introduced into the compressing chamber 11a from the intake chamber 13a, or is exhausted from the compressing chamber 11a into the exhaust room 13b.

the driving unit 20 provides a driving force to allow the piston 12 to reciprocate in the compressing chamber 11a, and includes a stator 21 fixed in the closed casing 1 and a rotor 22 which is spaced apart from the stator 21 so as to electro-magnetically interact with the stator 21. A rotating shaft 23 is provided on the center portion of the rotor 22 such that the rotating shaft 23 can rotate together with the rotor 22. Provided below the rotating shaft 23 are an eccentric portion 24, which is eccentrically rotated, and a connecting rod 25. In order to convert the eccentric movement of the eccentric portion 24 connecting rod 25. In order to convert the eccentric movement of the eccentric portion 24 into the linear movement, one end of the connecting rod 25 is rotatably coupled to the eccentric portion 24 and the other end of the connecting rod 25 is coupled to the piston 12 such that the connecting rod 25 can perform the linear and rotating movement.

When a power is applied to the hermetic compressor, the rotating shaft 23 is rotated according to an electromagnetic interaction between the stator 21 and the rotor 22, and the piston 12 which is connected with the eccentric portion 24 by means of the connecting rod 25 performs the linear reciprocation in the compressing chamber 11a. Through this process, the refrigerant remaining at the outside of the closed casing 1 is introduced into the intake chamber 13aof the cylinder head 13 through the intake tube 2 and then is transferred to the compressing chamber 11a so as to be compressed in the compressing chamber 11a. In this manner, the refrigerant compressed in the compressing chamber 11a is exhausted into the exhaust chamber 13b of the cylinder head 13 and is exhausted out of the closed casing 1 through an exhaust tube 4.

Meanwhile, a valve unit 30 includes a valve plate 40 which has an intake hole 41 and an exhaust hole (not shown) through which the compressing chamber 11a of the cylinder block 11 communicates with the intake chamber 13a and the exhaust chamber 13b of the cylinder 13. Further, an intake valve plate 35 having an intake valve 31, which opens/closes the intake hole 41, is assembled to one side surface of the valve plate 40 facing the cylinder block 11 and an exhaust valve assembly 50, which opens/closes the exhaust hole, is assembled to the other side surface of the valve plate 40 facing the cylinder head 13.

For reference, reference numerals 32 and 33 represent gaskets which are interposed between the cylinder head 13 and the valve plate 40, and between the cylinder block 11 and the intake valve plate 35, respectively. Bolt coupling holes are formed at outer peripheral portions of the gaskets, 32 and 33, the valve plate 40, and the cylinder head 13, respectively. Such a valve unit 30 is installed between the cylinder block 11 and the cylinder head 13 by means of a fixing bolt 34, which is screw-coupled into the bolt coupling hole from the outside the cylinder head 13 so as to be coupled with the cylinder block 11.

A peripheral portion of the intake valve 31, except for an end portion thereof, is cut from the intake valve plate 35 so that the intake valve 31 is integrally formed with the intake valve plate 35. At this time, one end portion of the intake valve 31 serves as a fixing end 31a fixed to the intake plate 35 and the tip portion of the intake valve 31 serves as a free end 31b, which is elastically deformed so as to open or close the intake hole 41.

Meanwhile, the piston 12, which is guided by the cylinder block 11 while moving in forward and backward directions, has a cylindrical shape and a compressing surface 12a of the piston 12 facing the intake valve plate 35 forms a flat surface which is parallel to the intake valve plate 35. Further, the compressing surface 12a has an anti-contact portion 60 so as to prevent the compressing surface 12a from making contact with the intake valve 31 during the reciprocation of the piston 12.

The anti-contact portion 60 is a recess having a shape corresponding to the shape of the intake valve 31 and the volume of the anti-contact portion 60 is set within a range which does not reduce the compressing efficiency of the hermetic compressor. In addition, the anti-contact portion 60 has a width larger than a width of the intake valve 31, so that the intake valve 31 can pass through the anti-contact portion 60 when the free end 31b of the intake valve 31 is bent to be received in the anti-contact portion 60.

In addition, since the free end 31b of the intake valve 31 is rotated about the fixing end 31a, the depth of the anti-contact portion 60 is gradually increased from the fixing end 31a to the free end 31b.

Hereinafter, the operation and functions of the hermetic compressor according to the exemplary embodiment of the present invention will be explained with reference to FIGS. 3 and 4.

FIG. 3 is a view representing a piston when the piston moves forward to the maximum extent so as to reach a top dead point. At this time, pressure is applied in a direction in which the piston 12 pushes the intake valve 31, so that the intake valve 31 does not open the intake hole 41.

FIG. 4 is a view representing positions of the piston 12 and the intake valve 31 when the piston 12 moves back from the top dead point to the bottom dead point. If the piston 12 reaches the top dead point and moves back to the bottom dead point, negative pressure is applied to an inside of the compressing chamber 11a, so that the free end 31b of the intake valve 31 is bent toward the inside of the compressing chamber 11a about the fixing end 31a.

In this case, the anti-contact portion 60, which can receive the free end 31b of the intake valve 31, is formed on the compressing surface 12a of the piston 12 so as to prevent the intake valve 31 from making contact with the piston 12.

As described above, the hermetic compressor according to the present invention can prevent the components from being damaged by preventing the intake valve from making contact with the piston, and can prevent the cylinder block from being worn by preventing debris derived from the breakage of the components from being introduced into the compressing chamber.

In addition, since the recess having a minimum volume is formed in the compressing surface of the piston, the distance between the piston and the intake valve plate can be reduced, so that the compressing efficiency of the compressor can be prevented from being degraded.

Claims

1. A hermetic compressor comprising:

a cylinder block having a compressing chamber;

a piston performing a reciprocation in the compressing chamber;

a cylinder head which is coupled to one side of the cylinder block so as to close the compressing chamber; and

an intake valve plate having an intake valve which is provided between the cylinder block and the cylinder head so as to control a flow of a refrigerant which is introduced into the compressing chamber,

wherein a compressing surface of the piston facing the intake valve plate forms a flat surface parallel to the intake valve plate, and an anti-contact portion which receives a part of the intake valve is formed on the compressing surface so as to prevent the piston from making contact with the intake valve during the reciprocation of the piston.

2. The hermetic compressor as claimed in claim 1, wherein the anti-contact portion includes a recess having a shape corresponding to a shape of the intake valve.

3. The hermetic compressor as claimed in claim 2, wherein the anti-contact portion has a width larger than a width of the intake valve so that the intake valve passes through the anti-contact portion.

4. The hermetic compressor as claimed in claim 2, wherein the intake valve is formed by cutting the intake valve plate, in which one end of the intake valve serves as a fixing end and the other end of the intake valve serves as a free end.

5. The hermetic compressor as claimed in claim 4, wherein a depth of the anti-contact portion gradually increases from the fixing end to the free end.

6. The hermetic compressor as claimed in claim 2, wherein a volume of the anti-contact portion is set within a predetermined range which does not reduce a compressing efficiency of the hermetic compressor.