WO2000011348A1

WO2000011348A1 - Hermetic compressor and manufacturing method for the same

Info

Publication number: WO2000011348A1
Application number: PCT/JP1998/003684
Authority: WO
Inventors: Terumasa Ide
Original assignee: Matsushita Refrigeration Co
Current assignee: Panasonic Holdings Corp
Priority date: 1998-08-19
Filing date: 1998-08-19
Publication date: 2000-03-02
Anticipated expiration: 2001-02-19

Abstract

The hermetic compressor of the present invention is provided with a suction muffler that can have a high welding strength and suppress burr generation by means that a pressure is applied to joint faces of the first and second cases of the synthetic resin suction muffler, facing each other at right angles to the joint face, then those joint faces facing each other are vibrated in the direction parallel to said joint face so that a frictional heat is generated between those joint faces and thereby the joint faces are welded.

Description

-Description- Hermetic Compressor and Manufacturing Method for the same

Technical Field

The present invention relates to a hermetic compressor for use with a refrigerating apparatus that uses a refrigerant for electrical refrigerators, air conditioners, etc. and a method for manufacturing the hermetic compressor.

Background Art

In recent years, HFC ( hydro-fluorocarbon) and HC (hydrocarbon) refrigerants that include no chlorine are used for refrigeration cycles in order not to destroy the ozonosphere. Furthermore, in order to prevent global temperatures rise, hermetic compressors having a high energy conversion efficiency respectively are now in great demand. And, it is well known that a low thermal conductivity material such as synthetic resin is suitable for configurating the suction muffler of such a hermetic compressor.

An example of well-known conventional hermetic compressors is disclosed in the official gazette of Examined Japanese Patent Application, Publication No. HEI 3-45212.

FIG. 8 is a top view of a structure of the conventional hermetic compressor. In FIG. 8, a closed vessel 101 is shown in a cross sectional view. Inside the closed vessel 101 are housed a compressing unit 102 and an electric unit 103. The compressing unit 102 and the electric unit 103 are elastically supported to the closed vessel 101. The compressing unit 102 has: a cylinder 104; a piston 105 that makes a reciprocating motion in the cylinder 104; a valve plate 106 attached to the compressing unit 102 so as to block an opening of the cylinder 104; and a cylinder head 107.

In FIG. 8, a suction muffler 108 is attached to the cylinder head 107 of the compressing unit 102. This suction muffler 108 is composed of two synthetic resin cases welded by supersonic-welding. A suction tube 109 is attached to the closed vessel 101 so as to pass it through. This suction tube as an intake tube 109 guides a refrigerant gas into the closed vessel 101.

In the conventional hermetic compressor constructed as described above, a refrigerant gas flown from the low pressure side of a refrigerating cycle is guided into the closed vessel 101 via the intake tube 109, then guided into the cylinder 104 via the suction muffler 108. The refrigerant gas led into the cylinder 104 is then compressed by the piston 105.

While such conventional hermetic compressor is manufactured, molded cases of the synthetic resin suction muffler are apt to be warped due to uneven injection pressures and uneven dies temperatures in the injection molding process. As a results, such warped cases generate well contact portions and non-contact portions when the cases are welded in the welding process . In such the welding process for the cases of the suction muffler, each contact portion between the cases is fused first, then the welding is gradually advanced all along the peripheries of the cases including non-contact portions. At this time, however, a difference is generated in the welding state between the first welded portion and the last welded portion due to a contact time difference. In other words, the welding state of each contact portion goes uneven due to a difference of the welding time. At a portion whose contact time is short, therefore, the non-contact portion between the two cases is not welded enough, leaving some portions as non-welded portions. In such way, a part of the portion to be welded generates a gap, so that much oil seeps into the suction muffler through the gap and compressed in the compressing unit 102. The compressed oil then causes valves to be damaged. The compressed oil also circulates and stays in the vaporizer, thereby to cause a refrigerating failure. Furthermore, the conventional hermetic compressor has also confronted with a problem that the cases of the suction muffler 108 are removed during an operation due to an insufficient strength of the welding junction between the cases, causing emission of an abnormal sound.

In order to solve the problems as described above, the welding strength and the air-tightness of the suction muffler 108 must be more improved. In the case of such the conventional hermetic compressor, therefore, to prevent such the problems, there are provided means for increasing the pressure for welding the cases and extending the welding time. When those means are used, however, a portion that takes a longer contact time is fused locally and projected as burr. This burr falls into the cylinder while the hermetic compressor is operating, disturbing the motion of the piston and causes the valve mechanism to be clogged and resulting in a compressing failure.

Disclosure of Invention

Under such the circumstances, it is an object of the present invention to solve the above-mentioned problems of the conventional hermetic compressor and provide a hermetic compressor having a suction muffler free from the burr falling into the cylinder as described above by welding the synthetic resin suction muffler uniformly and surely all along the peripheries of the cases.

In the hermetic compressor of the present invention, a vibration welding method is adopted to weld junctions of plural divided cases of the synthetic resin suction muffler.

Consequently, even when a case is warped, each welding portion of the suction muffler is fused uniformly all along the periphery without generating any gap between the cases. Thus, the welding strength is increased much significantly.

In the hermetic compressor of the present invention, junctions of the suction muffler are welded by vibration under pressing. In this case, a pressure is applied to those junctions before welding so that every welding portion is in contact with the other side welding portion all along the periphery. Then, the contact faces are fused with a frictional heat generated therebetween by vibration. The method can thus prevent generation of non- contact portions.

In the hermetic compressor of the present invention, a projection and a recess while are formed in complementary relation press-fit with a gap therebetween. Then, the projection and the recess are welded by vibration as described above. Even when any burr is generated in this case, the fused resin stays in the gap, so that no burr falls inside and outside the suction muffler.

The hermetic compressor of the present invention comprises : a compressing unit supported elastically in a closed vessel; an electric unit supported elastically in said closed vessel and used for driving said compressing unit; and a suction muffler attached to said compressing unit and having plural synthetic resin cases welded actually in uniform at fused portions using a vibration welding method.

The method for manufacturing the hermetic compressor of the present invention comprises: a- step for pressing welding faces of two resin cases of the suction muffler, facing each other, in the directions opposite to each other; a step for vibrating the welding faces in the direction substantially parallel to each welding face while performing the pressing step; and a step for ending the vibrating step, thereby ceasing the welding faces of the cases.

According to the method for manufacturing the hermetic compressor of the present invention, even when a case is warped from a designed shape, the welding portion of the case is fused uniformly and compactly all along the periphery without producing any hole or opening, so that the welding strength can be increased more significantly. While the novel features of the invention are set forth particularly in the appended claims, the invention, both as to organization and content, will be better understood and appreciated, along with other objects and features thereof, from the following detailed description taken in conjunction with the drawings.

Brief Description of Drawings

FIG. 1 is a top view of an inner configuration of a hermetic compressor in the first and second embodiments of the present invention;

FIG. 2 is a side view of an inner configuration of the hermetic compressor in the first and second embodiments of the present invention;

FIG. 3 is an exploded side view of a suction muffler in the first embodiment of the present invention;

FIG. 4 is a cross sectional view of an expanded portion A shown in FIG. 3;

FIG. 5 is an exploded side view of the suction muffler in the second embodiment of the present invention;

FIG. 6 is a cross sectional view of an expanded portion B shown in FIG. 5;

FIG. 7 is a cross sectional view of an expanded major portion of the suction muffler shown in FIG. 6 after it is welded; and

FIG. 8 is the top view of the inner configuration of the conventional hermetic compressor.

It will be recognized that some or all of the Figures are schematic representations for purposes of illustration and do not necessarily depict the actual relative sizes or locations of the elements shown.

Best Mode for Carrying Out the Invention

Hereunder, preferred embodiments according to a hermetic compressor of the present invention will be described with reference to FIGs. 1 to 7.

<<First Embodiments

FIG. 1 is a top view of a hermetic compressor in the first embodiment of the present invention. FIG. 2 is a side view of the hermetic compressor shown in FIG. 1. In FIGs. 1 and 2, a closed vessel 1 is shown in a cross sectional view.

As shown in FIGs. 1 and 2, in the closed vessel 1 are housed a compressing unit 2 and an electric unit 3. The compressing unit 2 and the electric unit 3 are elastically supported by a spring 3a in the closed vessel 1. The compressing unit 2 has: a cylinder 4; a piston 5 that makes a reciprocating motion in the cylinder 4; a valve plate 6 attached to the cylinder so as to block an opening of the cylinder 4; and a cylinder head 7.

A suction muffler 8 is attached to the cylinder head 7 of the compressing unit 2, and this suction muffler 8 is configured by two synthetic resin cases welded by friction heat of vibration, that is a vibration welding method. An intake tube 9 (FIG. 1) is attached to the closed vessel 1 so as to pass through the closed vessel 1. This intake tube leads a refrigerant gas into the closed vessel 1.

FIG. 3 is an exploded side view of the front side of the suction muffler 8 in the hermetic compressor in the first embodiment of the present invention. FIG. 4 is an expanded view of the "A" portion shown in FIG. 3, indicating a cross sectional view of the suction muffler shown in FIG. 3 in a welding process.

As shown in FIG. 3, the suction muffler 8 comprises the first case 10 and the second case 11. Both the first and second cases 10 and 11 are injection-molded with polybutylene terphthalate (hereafter, to be abbreviated as PBT). A flange 12 is formed on the first case 10 and a flange 14 is formed on the second case 11. A frame 11a for holding the suction muffler 8 is provided at a lower position of the second case 11.

As shown in FIG. 4, the flange 12 of the first case 10 has a joint face 13 facing the second case 11. The flange 14 of the second case 11 has a joint face 15 facing the first case 10. As shown in FIG. 4, the flange 12 of the first case 10 is disposed so as to engage with a plate 16A attached to a pressing device (not shown) and the second case 11 is held by a rest 16B of the pressing device.

Next, a method for manufacturing the suction muffler 8 will be described. The suction muffler 8 is used in the hermetic compressor in the first embodiment constructed as described above.

At first, the first and second cases 10 and 11 of the suction muffler 8 are mounted in the pressing device. The plate 16A is engaged with the flange 12 and the rest 16B is engaged with the flange 14. The first and second cases 10 and 11 mounted in the pressing device such way are pressed by the plate 16A and the rest 16B in the directions opposite to each other. Consequently, the flange 12 of the first (upper half) case 10 is pressed by the plate 16A from the direction at right angles to the joint face. The flange 14 of the second (lower half) case 11 is pressed by the rest 16B in the direction at right angles to the joint face 15. Consequently, even when any of the joint faces 13 and 15 is warped, the first and second cases 10 and 11 are deformed elastically, so that the joint faces 13 and 15 come in contact with each other completely all along the periphery.

While the joint faces 13 and 15 are evenly pressed and are in contact with each other as described above, if a fixed vibration mode that vibrates in the direction parallel to the joint faces 13 and 15, for example, if a vibration with a frequency of 240Hz is applied to the first case 10, each of the joint faces 13 and 15 is fused with a frictional heat generated therebetween. In such a vibration process, a preferred vibration welding is performed with vibrations within a frequency of 240Hz.

After the vibration in the above vibration mode is stopped, the fused portions on each of the joint faces 13 and 15 solidify and the joint faces 13 and 15 stick to each other. As a result, the first and second cases are welded evenly and formed integral .

When such a vibration welding method is used in the welding process for the suction muffler 8 of the hermetic compressor in the first embodiment, the welding time is almost fixed at any portions on the joint faces 13 and 15 of the suction muffler 8. The joint faces 13 and 15 are thus welded all along their peripheries almost in evenly. Consequently, the suction muffler 8 of the hermetic compressor in the first embodiment can secure air-tightness and welding strength satisfactorily.

In the vibration welding method as described above, vibration is generally applied in a linear reciprocating direction in parallel to each joint face. There is another vibration welding method, which is called an orbital vibration method. In this method, the vibration orbital is trailed almost like an ellipse. This orbital welding method can obtain a longer orbital of the vibration with a smaller amplitude when compared with the linear vibration welding method. The orbital vibration welding method can thus reduce joint faces, so it has an effect to reduce the size of the suction muffler 8 in its external view.

<<Second Embodiment>>

Next, the second embodiment of the hermetic compressor according to the present invention will be described with reference to the accompanying drawings. The configuration of the hermetic compressor in the second embodiment is substantially the same as that in the first embodiment except for the suction muffler 80.

FIG. 5 is a side view of the exploded suction muffler used in the hermetic compressor in the second embodiment of the present invention. FIG. 6 is an expanded cross section view of the suction muffler shown in FIG. 6 after the welding process is ended.

As shown in FIG. 5, the suction muffler 80 is comprises the first and second cases 17 and 18. The first and second cases 17 and 18 are injection-molded with PBT. A flange 19 is formed on the first case 17 and a flange 23 is formed on the second case 18. A frame 18a for holding the suction muffler 80 is provided at a lower position of the second case 18.

As shown in FIG. 6, a projection 20 is formed on the first case 17, at a portion facing the second case 18. On the face of the projection 20, a tip face 21 and a contact face 22 are formed to face the second case 18.

A flange 23 is formed on the second case 18. At a portion on the second case 18, a recess 24 is formed to face the first case 17. In the recess 24 are formed a bottom face 25 so as to face the tip face 21 of the first case 17 and an edge face 26 so as to face the contact face 22 of the first case 17.

As shown in FIG. 6, the height value "h" of the projection 20 is greater than the depth value "d" of the recess 24 (h>d). The projection 20 of the first case 17 and the recess 24 of the second case 18 are formed so as to face each other all along the peripheries of the edges of the cases 17 and 18. When the first case 17 is combined with the second case 18 and the projection 20 is fit in the recess 24, a gap is formed between the projection 20 and the recess 24 to have a length of an amplitude of the vibration welding or over. The projection 20 is thus floatingly fit in the recess 24.

As shown in FIG. 6, the width "tl" of the tip face of the projection 20 is formed narrower than the width "t2" of the bottom face 25 of the recess 24 (tl<t2).

In FIG. 6, a numeral 27 indicates a gap formed between the projection 20 and the recess 24. A numeral 28 indicates an end portion of fusion of the projection 20 having a height, which is equal to a difference (h-d) between the height h and the depth d of the recess 24. The volume of the fusion end portion is V. The space volume W of the gap formed between the projection 20 and the recess 24 is set larger than the volume V of the fusion end portion 28 of the projection 20 (W>V).

In FIG. 6, the flange 19 of the first case 17 is disposed so as to engage with the plate 29 attached to the pressing device (not shown). The second case 18 is held by the rest 30 of the pressing device.

Next, a method for manufacturing the suction muffler 80 will be described. The suction muffler 80 is used in the hermetic compressor in the second embodiment composed as described above.

At first, the first and second cases 17 and 18 of the suction muffler 80 are mounted in the pressing device. The plate 29 is engaged with the flange 19 and the rest 30 is engaged with the flange 23. The first and second cases 17 and 18 mounted in the pressing device such way are pressed by the plate 29 and the rest 30 in the directions opposite to each other. Consequently, the flange 19 of the first case 17 is pressed by the plate 29 from the direction at right angles to the tip face 21, which is a joint face. The flange 23 of the second case 18 is pressed by the rest 30 in the direction at right angles to the bottom face, which is a joint face. Consequently, even when any of the tip face 21 and the bottom face 25 is warped, the first and second cases 10 and 11 are deformed elastically and thereby the tip face 21 and the bottom face 25 come in contact with each other all along the periphery.

While the tip face 21 and the bottom face 25 are pressed in uniform and are in contact with each other as described above, when a fixed vibration mode that vibrates in the direction parallel to the joint faces and, for example, a frequency of 240Hz is applied to the first case 17 and the bottom face 25, each of the joint faces between the tip face 21 and the bottom face 25 is fused with a frictional heat generated therebetween. Thus, the fusing end portion 28 of the projection 20 is fused.

After the vibration in the above vibration mode is stopped, the fused end portion 28 of the projection 20 is solidified. The first and second cases 17 and 18 thus stick to each other.

FIG. 7 is an expanded cross sectional view of the first and second cases of the suction muffler 80, fastened to each other, using the vibration welding method as described above.

As shown in FIG. 7, in the gap 27 formed between the projection 20 and the recess 24, burr is formed at a fused portion of the fusing end 28 of the resin projection 20. In the hermetic compressor in the second embodiment, constructed as described above, the tip face 21 of the projection 20 and the bottom face 25 of the recess 24 are fused in a welding process for the suction muffler 80 with a frictional heat generated between them 21 and 25 that are in contact with each other. And, this fused resin burr 31 is received in the gap 27. In this welding process, the welding is ended when the contact face 22 of the first case 17 comes in contact with the edge face 26 of the second case 18 and thereby the gap becomes almost zero. The volume of the burr 31 fused at this time is equal to the fused portion 28 of the projection 20. Since the volume of the fused burr 31 is smaller than the space volume of the gap 27, the fused burr 31 falls into the space of the gap 27 completely. Consequently, the burr 31 never falls inside and outside of the suction muffler 80.

According to the present invention as described above, since junction faces of the suction muffler are welded in uniform and no gap is generated between junction faces, it is possible to obtain a highly reliable hermetic compressor in which proper air- ightness and welding strength are secured at junction faces of the suction muffler, as well as to obtain a method for manufacturing such the hermetic compressor.

Furthermore, according to the present invention, since the projection and the recess of the suction muffler, which are facing each other, are fit with a gap therebetween and fused resin is fallen in this gap, fused resin burr never falls inside and outside the suction muffler. It is thus possible to obtain a still more highly reliable hermetic compressor and a method for manufacturing such the hermetic compressor.

Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that such disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains, after having read the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention.

Industrial Applicability

A hermetic compressor of the present invention is used for a refrigerating apparatus that uses a refrigerant for electrical refrigerators, air conditioners and the like.

Claims

1. A hermetic compressor comprising: a compressing unit supported elastically in a closed vessel; an electric unit supported elastically in said closed vessel and used for driving said compressing unit; and a suction muffler attached to said compressing unit and having plural synthetic resin cases welded actually in uniform at fused portions using a vibration welding method.

2. The hermetic compressor in accordance with claim 1, which is provided with a suction muffler comprising cases facing each other therein, wherein a projection is formed on a joint face of one case and a recess is formed on a joint face of the other case so as to face said projection, said projection being press- fittingly welded in said recess so that a fused portion of said projection is received in a gap formed between said projection and said recess.

3. The hermetic compressor in accordance with claim 2, wherein on each joint face formed at an edge of said cases facing each other in said suction muffler, the height of belt-like projection is greater than a depth of said recess, a width of said projection is narrower than a width of said recess, and said gap formed between said projection and said recess in the width direction is set to have a length of the amplitude of vibration welding, as well as a space volume of said gap formed in said width direction is set larger than the volume of said projection fused when said first and second cases and are welded.

4. A method for manufacturing a hermetic compressor comprising steps of: pressing joint faces of resin cases facing each other in suction muffler in directions opposite to each other; vibrating said joint faces of said cases in parallel to each of said joint faces while performing said pressing process; and ending said vibrating process, then welding said joint faces of said cases.

5. The method for manufacturing the hermetic compressor in accordance with claim 4, wherein a projection is formed on one of said cases facing each other in said suction muffler and a recess is formed on the other case, a height of said projection is set greater than a depth of said recess, a width of said projection is set narrower than the width of said recess, a gap formed between said projection and said recess in the width direction is set longer than the length of the amplitude of said vibration welding, and a space volume of said gap formed in said width direction is set larger than the volume of said projection fused when said cases are welded.