Hermetic type compressor

Abstract

A hermetic type compressor including balance weights installed on a rotor so as to compensate for rotating unbalance of a rotary shaft, thereby reducing a level of noise. The hermetic type compressor has a compressing unit, which compresses a refrigerant, a driving unit, which provides driving force to compress the refrigerant, a stator, a rotor that rotates in electromagnetic interaction with the stator, and a rotary shaft, which is press-fit into a center of the rotor so as to transmit the driving force of the driving unit to the compressing unit, and has an eccentric part on one end thereof. The rotor has balance weights so as to compensate for rotating unbalance of the rotary shaft caused by the eccentric part on upper and lower ends thereof, where each balance weight has a shape of a ring, part of which has at least a hollow space.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2007-0030159, filed on Mar. 28, 2007, 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 disclosure relates to a hermetic type compressor. More particularly, the present disclosure relates to a hermetic type compressor in which balance weights, which are installed on a rotor so as to compensate for rotating unbalance of a rotary shaft, are structurally improved.

2. Description of the Related Art

In general, a compressor applied to a refrigeration cycle for a refrigerator or an air conditioner has a hermetic case for an outward appearance. The hermetic case is equipped therein with a driving unit providing driving force for compressing a refrigerant, and a compressing unit receiving the driving force from the driving unit and compressing the refrigerant.

The driving unit comprises a stator, and a rotor installed in the stator so as to rotate in electromagnetic interaction with the stator. A rotary shaft is press-fit into the center of the rotor. Further, the rotary shaft includes an eccentric part at one end thereof so as to be eccentric to the central axis of the rotary shaft. The compressing unit compresses the refrigerant using eccentric motion of this eccentric part.

Thus, during compressing the refrigerant, the rotary shaft causes vibration or noise while rotating in an unbalanced state due to the eccentric motion of the eccentric part. In order to compensate for this rotating unbalance, the rotor includes balance weights having a predetermined mass at upper and lower ends thereof, which are disposed so as to cross each other at an angle of 180 degrees. Each balance weight usually has the shape of a semi-ring because it is disposed around the rotary shaft.

FIG. 1 illustrates the structure of a conventional hermetic type compressor, in which a balance weight is coupled to the upper end of a rotor. For reference, a reference number 3 indicates a rotary shaft.

In the case of this conventional hermetic type compressor, since the balance weight 2 is disposed so as to be eccentric to the central axis of the rotary shaft 3, a leading end of the rotating balance weight 2 excites vibration of a fluid such as a refrigerant inside a hermetic case when the rotary shaft 3 of the rotor 1 rotates to compress the refrigerant. As a result, aeroacoustic noise of a specific frequency is caused in the hermetic case, and thus overall driving noise of the hermetic type compressor is increased.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present disclosure to provide a hermetic type compressor, in which balance weights installed on a rotor so as to compensate for rotating unbalance of a rotary shaft are structurally improved, thereby reducing a level of noise.

Additional aspects and/or advantages of the disclosure will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosure.

The foregoing and/or other aspects of the present disclosure are achieved by providing a hermetic type compressor, which comprises a compressing unit, which compresses a refrigerant, a driving unit, which provides driving force to compress the refrigerant, and comprises a stator and a rotor installed in the stator so as to rotate in electromagnetic interaction with the stator, and a rotary shaft, which is press-fit into a center of the rotor so as to transmit the driving force of the driving unit to the compressing unit, and comprises an eccentric part on one end thereof. The rotor comprises balance weights so as to compensate for rotating unbalance of the rotary shaft caused by the eccentric part on upper and lower ends thereof, each balance weight has a shape of a ring, part of which has at least a hollow space.

According to an aspect of the present disclosure, each balance weight comprises a solid part and a hollow part, both of which are integrally formed with each other and have a shape of a semi-ring.

According to an aspect of the present disclosure, each balance weight comprises a solid part and a hollow part, both of which are separately formed and coupled with each other and have a shape of a semi-ring.

According to an aspect of the present disclosure, the hollow part is open to one face thereof which is in contact with the rotor.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a plan view illustrating the structure of a conventional hermetic type compressor, in which a rotor is rotating in the state in which a balance weight is coupled to a rotor;

FIG. 2 is a sectional view illustrating the overall structure of a hermetic type compressor according to an exemplary embodiment of the present disclosure;

FIG. 3 is a perspective view illustrating the partial structure of a hermetic type compressor according to an exemplary embodiment of the present disclosure, in which balance weights are decoupled from a rotor;

FIG. 4 is a plan view illustrating the structure of a hermetic type compressor according to an exemplary embodiment of the present disclosure, in which a rotor is rotating in the state in which balance weights are coupled to a rotor; and

FIG. 5 is a perspective view illustrating the structure of a balance weight according to another exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present disclosure by referring to the figures.

As illustrated in FIG. 2, a reciprocating type compressor of the present disclosure comprises a hermetic case 10, in which an upper case 10a and a lower case 10b are coupled to each other. The hermetic case 10 comprises an inlet pipe 11 and an outlet pipe 12 on one side thereof. The inlet pipe 11 guides a refrigerant from the exterior to the interior of the hermetic case 10, while the outlet pipe 12 guides the refrigerant compressed in the hermetic case 10 to the exterior of the hermetic case 10.

The hermetic case 10 is equipped therein with a compressing unit 20 compressing the refrigerant, and a driving unit 20 providing driving force to compress the refrigerant. The compressing unit 20 and the driving unit 20 are installed through a frame 40.

The driving unit 30 comprises a stator 31 fixed around a lower portion of the frame 40, and a rotor 32 installed in the stator 31 so as to rotate in electromagnetic interaction with the stator 31.

Further, the compressing unit 20 comprises: a cylinder 21, which is integrally formed with the frame 40 on one side of the upper portion of a through-hole 41 at the center of the frame 40 so as to form a compression chamber 21a for compressing the refrigerant; a piston 22, which reciprocates in the compression chamber 21a and compresses the refrigerant; a cylinder head 23, which is coupled to one end of the cylinder 21 so as to airtightly close the compression chamber 21a and is partitioned into a refrigerant discharge chamber 23a and a refrigerant intake chamber 23b; and a valve 24, which is interposed between the cylinder 21 and the cylinder head 23, and regulates a flow of the refrigerant that is either drawn from the refrigerant intake chamber 23b into the compression chamber 21a or discharged from the compression chamber 21a to the refrigerant discharge chamber 23a. Here, the refrigerant intake chamber 23b guides the refrigerant, which is delivered into the hermetic case 10 through the inlet pipe 11, to the compression chamber 21a. The refrigerant discharge chamber 23a cooperates with the outlet pipe 12. An intake muffler 13 serves to guide the refrigerant flowing into the hermetic case 10 through the inlet pipe 11 to the refrigerant intake chamber 23b in the state where pulsating pressure is reduced.

The driving force of the driving unit 30 is transmitted to the compressing unit 20 through a rotary shaft 50. The rotary shaft 50 is rotatably installed in the through-hole 41 at the center of the frame 40. The rotary shaft 50 is press-fit into the center of the rotor 32 at a lower portion of the frame 40 so as to be rotated together with the rotor 32, and comprises an eccentric part 51, which is eccentric to the central axis of the rotary shaft 50 and is eccentrically rotated about the central axis of the rotary shaft 50, at an upper end thereof at an upper portion of the frame.

Further, a connecting rod 25 is connected between the eccentric part 51 and the piston 22 in order to convert rotating motion of the rotary shaft 50 into reciprocating motion of the piston 22.

According to this construction, when the rotary shaft 50 is rotated together with the rotor 32 by electromagnetic interaction between the stator 31 and the rotor 32, the piston 22 connected with the eccentric part 51 through the connecting rod 25 reciprocates in the compression chamber 21a. Thereby, the refrigerant guided into the hermetic case 10 along the inlet pipe 11 is drawn into the compression chamber 21a via the refrigerant intake chamber 23b of the cylinder head 23, and is compressed in the compression chamber 21a. The refrigerant compressed in the compression chamber 21a is discharged to the outside of the hermetic case 10 via the refrigerant discharge chamber 23a of the cylinder head 23 and the outlet pipe 12. This process is repeated. Thereby, the refrigerant is compressed by the compressor.

Meanwhile, while the refrigerant is compressed, the rotary shaft 50 is rotated in an unbalanced state due to the eccentric rotation of the eccentric part 51 and the reciprocating motion of the piston 22 that occurs in a direction perpendicular to the rotary shaft 50. As a result, the rotary shaft 50 causes vibration or noise.

Thus, in order to compensate for the rotating unbalance of the rotary shaft 50, first and second balance weights 60 and 70 are installed on upper and lower ends of the rotor 32 respectively. In this embodiment, each of the first and second balance weights 60 and 70 has an annular appearance, as illustrated in detail in FIG. 3.

The first and second balance weights 60 and 70 comprise solid parts 61 and 71, and hollow parts 62 and 72. The solid parts 61 and 71 and the hollow parts 62 and 72 have the shape of a semi-ring. The first balance weight 60 is constructed in a manner such that the solid part 61 is integrally formed with the hollow part 72 in a ring shape. This is equally true of the second balance weight 70.

Here, the solid parts 61 and 71 of the first and second balance weights 60 and 70 function to compensate for the rotating unbalance of the rotary shaft 50. The first and second balance weights 60 and 70 are disposed so as to cross each other at an angle of 180 degrees when installed on the upper and lower ends of the rotor 32.

Further, each of the first and second balance weights 60 and 70 having the annular appearances is symmetrical in all directions and does not protrude outwardly from the outer surface thereof. As such, the fluid such as the refrigerant in the hermetic case 10 does not excite vibration when the rotor 32 is rotated as illustrated in FIG. 4. As a result, the hermetic type compressor of this embodiment can inhibit aeroacoustic noise attributable to the rotation of the balance weights 60 and 70 in the hermetic case 10, and thus reduce overall driving noise.

These balance weights 60 and 70 can be fixed to the rotor 32 using rivets 32a. To this end, the solid parts 61 and 71 comprise fastening through-holes 61a and 71a for fastening the rivets 32a.

The hollow parts 62 and 72 are adapted to form open faces 62a and 72a so as to allow the hollow interiors thereof to communicate with the exteriors thereof. All of the remaining faces other than the open faces 62a and 72a are closed. These open faces 62a and 72a can facilitate forming the balance weights 60 and 70.

In other words, the balance weights 60 and 70 can be prepared by forging a solid metal member having the shape of a complete ring or by casting. In the case in which each of the balance weights 60 and 70 is adapted so that one face thereof is partly open, this may make it difficult to form a hollow space when the balance weights 60 and 70 are formed. For this reason, the open faces 62a and 72a of the balance weights 60 and 70 are formed so as to completely open.

Further, in the case in which the open faces 62a and 72a are exposed outside in the state where the balance weights 60 and 70 are installed on the rotor 32, the refrigerant in the hermetic case 10 may excite vibration on inner walls of the hollow parts 62 and 72. As such, when the first balance weight 60 is installed on the upper end of the rotor 32, the open face 62a of the first balance weight 60 preferably faces the upper end of the rotor 32 so as to be in contact with the upper end of the rotor 32. Similarly, when the second balance weight 70 is installed on the lower end of the rotor 32, the open face 72a of the second balance weight 70 preferably faces the lower end of the rotor 32 so as to be in contact with the lower end of the rotor 32.

Further, in this embodiment, the solid part 61 and the hollow part 62 are formed in one body, and the solid part 71 and the hollow part 72 are also formed in one body. However, in another embodiment of the present disclosure, as illustrated in FIG. 5, the solid parts 61′ and 71′ are fabricated apart from the hollow parts 62′ and 72′, and then are coupled to the hollow parts 62′ and 72′.

In the other embodiment, the solid parts 61′ and 71′ are coupled to the hollow parts 62′ and 72′ by bolts 100. Alternatively, the solid parts 61′ and 71′ may be coupled to the hollow parts 62′ and 72′ by an adhesive. The hollow parts 62′ and 72′ are also adapted to form open faces 62a and 72a in the directions in which they are in contact with the rotor 32.

As described in detail above, according to the present disclosure, the hermetic type compressor is adapted so that the balance weights installed on the rotor comprise the solid parts and the hollow parts, and form the annular appearances on the whole.

Thus, the hermetic type compressor compensates for the rotating unbalance of the rotary shaft by means of the solid parts, and prevents the balance weights from exciting the vibration of the fluid in the hermetic case when the rotor is rotated, so that the aeroacoustic noise can be inhibited from occurring in the hermetic case, and thus the overall driving noise can be effectively reduced.

Although few embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents.

Claims

1. A hermetic type compressor comprising:

a compressing unit, which compresses a refrigerant;

a driving unit, which provides driving force to compress the refrigerant, and comprises a stator and a rotor installed in the stator so as to rotate in electromagnetic interaction with the stator; and

a rotary shaft, which is press-fit into a center of the rotor so as to transmit the driving force of the driving unit to the compressing unit, and comprises an eccentric part on one end thereof,

wherein the rotor comprises balance weights so as to compensate for rotating unbalance of the rotary shaft caused by the eccentric part on upper and lower ends thereof, each balance weight has a shape of a ring, part of which has at least a hollow space.

2. The hermetic type compressor as claimed in claim 1, wherein each balance weight comprises a solid part and a hollow part, both of which are integrally formed with each other and have a shape of a semi-ring.

3. The hermetic type compressor as claimed in claim 1, wherein each balance weight comprises a solid part and a hollow part, both of which are separately formed and coupled with each other and have a shape of a semi-ring.

4. The hermetic type compressor as claimed in claim 2 or 3, wherein the hollow part is open to one face thereof which is in contact with the rotor.