Sealed type compressor

Abstract: An attempt has been made to prevent damage of a hermetic terminal and to improve pressure-resistance strength of the welded joint of connecting pipes in order to provide a sealed housing 4 having a pressure-resistance strength high enough to allow use of a high-pressure alternative refrigerant. For this purpose, ring-shaped metal members 15 and 23 are welded to the outer peripheries of the welded joints of a hermetic terminal 8 to be hermetically welded to an upper end plate 1 of a sealed housing 4 and a discharge pipe 10. As a result, in the event the internal pressure of the sealed housing 4 increases and the upper end plate 1 deforms in the shape of a sphere, the ring-shaped metal member 15 on the outer periphery of the welded joint of the hermetic terminal 8 suppresses the deformation of the hermetic terminal 8 thus preventing damage of a glass seal 12 of the hermetic terminal 8, and the ring-shaped metal member 23 on the outer periphery of the welded joint of the discharge pipe 10 decreases the tensile stress produced in the welded joint of the discharge pipe 10 thus improving the pressure-resistance strength of the connecting section of the discharge pipe 10 thereby providing a sealed type compressor having a sealed housing 4 with a sufficiently high pressure-resistance strength.

Description: FIELD OF THE INVENTION The present invention relates to a sealed type compressor to be used as a refrigerant compressor for refrigerating and air conditioning or as an air compressor. BACKGROUND OF THE INVENTION In a conventional refrigerant compressor of this type, a compression mechanism 105 and a motor 106 to drive the compression mechanism 105 are fixed inside a sealed housing 104 which comprises an upper end plate 101, a body section 102, and a lower end plate 103 as shown in Fig. 20. The source of power to the motor 106 is supplied from an external power supply (not shown) through a hermetic seal 110 having an electrically conducting pin 109 insulated with a glass seal 108 on a cup-shaped metal member 107 which is hermetically sealed on the sealed housing 104. A refrigerant is sucked through a suction pipe 111 leading to a refrigeration circuit (not shown) into the compression mechanism 105, compressed, and discharged under a high pressure into the sealed housing 104, and returned to the refrigeration circuit (not shown) through a discharge pipe 112. Therefore, inside of the sealed housing 104 of this type of compressor is filled with a high-pressure refrigerant. Although HCFC22 has heretofore been employed as a refrigerant for this type of compressors, a decision has been reached to completely abolish it in the future because of a possibility of depleting the ozone layer by its emission into the air. Among several alternative HFC-based refrigerants to replace HCFC22, R407C, which is a mixture of HFC125, HFC32, and HFC134a, and R410A, which is a mixture of HFC125 and HFC32, are considered to be promising candidates. While the discharge pressure of R407C is approximately equal to that of R22, the discharge pressure of R410A is approximately 1.7 times that of R22. When using an alternative refrigerant having such a high discharge pressure in a sealed type compressor of high-pressure type in which the discharge pressure is applied to the sealed housing itself, the pressure-resistance strength of the sealed housing needs to be increased. However, in the above-mentioned prior art structure, as the internal pressure of the sealed housing 104 increases, the upper and lower end plates 101 and 103 swell outward gradually assuming a sphere-like shape. As the hermetic terminal 110 is fixed by welding to a flat section of the upper end plate 101, the deformation causes a stress on the cup shaped metal member 107 of the hermetic terminal 110, thus deforming it and breaking the glass seal 108, and leaking the high-temperature high-pressure refrigerant to outside. In the prior art construction, as this is the section of which the pressure-resistance is the weakest, it is necessary to increase pressure-resistance strength of this section in order to increase the pressure-resistance strength of the entire sealed housing. Also, the joints between the sealed housing 104 and the connecting pipes for the refrigerant, namely, the suction pipe 111 and the discharge pipe 112, are parts with the weakest pressure-resistance strength after the hermetic terminal 110 because a tensile stress is exerted due to the high pressure inside the sealed housing 104. EP-A-0183332 discloses a suction tube seal for a compressor in which the suction tube is received in an aperture having an inside diameter greater than the outside diameter of the tube, and a flexible sealing means is interposed therebetween. SUMMARY OF THE INVENTION The present invention has been contrived in order to address the above-described problems of the prior art, and is aimed in particular to prevent breakage of the glass seal of the hermetic terminal, and additionally to improve the pressure-resistance strength of the joints between the sealed housing and connecting pipes for a refrigerant, and to provide a sealed housing with a pressure-resistance strength high enough to withstand high-pressure alternative refrigerants. This invention provides a sealed type compressor comprising: a sealed housing wherein a motor and a compression mechanism to be driven by said motor are disposed; and a hermetic terminal hermetically welded to said sealed housing for supplying power to said motor from outside said sealed housing; said hermetic terminal comprising: a cup-shaped metal member; an electrically conducting pin; and a glass seal to insulate between said cup-shaped metal member and said electrically conducting pin; wherein means is provided around said hermetic terminal to enhance rigidity against deformation of said sealed housing. In one embodiment, the rigidity enhancing means comprises a member welded encircling the welded joint between said sealed housing and said hermetic terminal. In this arrangement, the member to increase deformation rigidity of the sealed housing is preferably a ring-shaped metal member having a thickness greater than 1/3 of the thickness of the sealed housing, and the weld where the ring shaped metal member is welded to the sealed housing is preferably an arc in shape. By so doing, the deformation rigidity of that section of the sealed housing where the ring-shaped metal member is welded effectively suppresses deformation of the hermetic terminal. In one embodiment, the ring-shaped metal member is welded to the inside of the sealed housing. By welding to the inside, obstruction to a protecting frame member of the hermetic terminal to be formed on the outside and to wiring around leads of the power supply can be avoided. In another embodiment, by welding the ring-shaped metal member to the outside of the sealed housing preferably integrally with a protecting frame member of the hermetic terminal, welding of the hermetic terminal to the sealed housing is not obstructed, and integral welding with the protecting frame member is possible, thus making assembly work easy. Also, in particular embodiments of this invention, either by providing a linear protrusion on the welded joint with the sealed housing when welding the ring-shaped metal member to the sealed housing, or by resistance welding as is when the width of the ring is small, the entire ring surface is fixed by welding to the end plates and the like of the sealed housing, thereby the deformation rigidity of the end plates and the like of the sealed housing effectively suppress deformation of the hermetic terminal. When carrying out resistance welding, the width of the ring-shaped metal member will need to be narrowed in order to increase the current density. Alternatively, the rigidity enhancing means may comprise burring around a hole in said sealed housing and the hermetic terminal is hermetically welded to the hole. In this case deformation of the peripheral edge of the hermetic terminal is made difficult to take place because of burring, thus making it possible to prevent breakage of the glass seal and improve the pressure-resistance strength. When burring is provided on the inside of the sealed housing, hermetic welding of the hermetic terminal becomes easy. When burring is provided on the outside of the sealed housing, deforming force exerted to the glass seal becomes smaller than when burring is provided on the inside. In a further embodiment the rigidity enhancing means comprises a plate to which the hermetic terminal is once hermetically welded followed by hermetically welding the plate on the end plate etc. of the afore-mentioned sealed housing with some overlap between them, thus making inside of the sealed housing high in pressure. As the rigidity of the overlapping section is large, even when the end plates etc. of the sealed housing onto which the hermetic terminal is welded are deformed, deformation of the hermetic terminal is suppressed, breakage of the glass seal of the hermetic terminal is prevented, and the pressure-resistance strength is improved. When the thickness of the plate on to which the hermetic terminal is hermetically welded is greater than the thickness of the sealed housing (end plates etc.), and when the length of the overlap of the plate and the sealed housing is greater than the thickness of the sealed housing, the effect of suppressing deformation of the hermetic terminal and preventing breakage of the glass seal becomes more prominent. Preferably the plate is a steel plate. Also, this invention is especially effective in a sealed type compressor in which the afore-mentioned sealed housing comprises a body section and an end plate to close an opening of the body section, and a hermetic terminal is hermetically welded to the end plate. In another embodiment, the sealed type compressor further comprises a connecting pipe connecting the inside and the outside of said sealed housing and through which a refrigerant goes in and out fixed by welding to said sealed housing, and a ring-shaped metal member welded around the outer periphery of the weld. By welding the ring-shaped metal member to the outer periphery of the welded joint of the connecting pipes, the tensile stress produced in the welded joint by the deformation due to internal pressure of the sealed housing is reduced and the pressure-resistance strength of the connecting sections of the connecting pipes is improved. Also, it is preferable to weld the connecting pipes to a burring-processed hole of the sealed housing for further improvement of the pressure-resistance strength. Furthermore, as the connecting pipes are generally welded by copper brazing, assembling becomes easy if the nearby ring-shaped metal member is brazed at the same time. Also this invention is more effective when a high-pressure refrigerant HFC32 or a mixed refrigerant containing HFC32 is used as the refrigerant. Advantageously then, in this invention inside of the sealed housing becomes high in pressure, and, in the case of the hermetic terminal, even when the sealed housing to which the hermetic terminal and connecting pipes for refrigerant are welded is deformed, the rigidity member such as the ring-shaped metal member joined to the outer periphery of the welded joint of the hermetic terminal suppresses the deformation of the hermetic terminal and prevents breakage of the glass seal of the hermetic terminal, whereas, in the case of the connecting pipes, the ring-shaped metal member joined to the outer periphery of their welded joints reduces the tensile stress produced in the welded joints, thus improving the joining strength of the connecting pipes and improving the pressure-resistance strength of the sealed housing. BRIEF DESCRIPTIONOF THE DRAWINGS Fig.1 is a vertical cross sectional view of a sealed type compressor in a first exemplary embodiment of the present invention, Fig. 2 is a vertical cross sectional view of a hermetic terminal section of the compressor, Fig. 3 is a cross sectional view of a ring-shaped metal member of the compressor, Fig. 4 is a vertical cross sectional view of other configuration 1 of the hermetic terminal section, Fig. 5 is a vertical cross sectional view of other configuration 2 of the hermetic terminal section, Fig. 6 is a vertical cross sectional view of other configuration 3 of the hermetic terminal section, and Fig. 7 is a vertical cross sectional view of other configuration 4 of the hermetic terminal section. Fig. 8 is a vertical cross sectional view of a hermetic terminal section in a second exemplary embodiment of the present invention, Fig. 9 is a vertical cross sectional view of other configuration 1 of the hermetic terminal section, and Fig. 10 is a vertical cross sectional view of other configuration 2 of the hermetic terminal section. Fig. 11 is a vertical cross sectional view of a hermetic terminal section in a third exemplary embodiment of the present embodiment. Fig. 12 is a vertical cross sectional view of a connecting pipe section in a fourth exemplary embodiment of the present invention. Fig. 13 is a vertical cross sectional view of other configuration 1 of the connecting pipe section, Fig. 14 is a vertical cross sectional view of other configuration 2 of the connecting pipe section, Fig. 15 is a vertical cross sectional view of other configuration 3 of the connecting pipe section, Fig. 16 is a vertical cross sectional view of other configuration 4 of the connecting pipe section, and Fig. 17 is a vertical cross sectional view of other configuration 5 of the connecting pipe section. Fig. 18 is a vertical cross sectional view of a connecting pipe section in a fifth exemplary embodiment of the present invention. Fig. 19 is a vertical cross sectional view of a connecting pipe section in a sixth exemplary embodiment of the present invention. Fig. 20 is a cross sectional view of a prior art sealed type compressor. DESCRIPTION OF THE PREFERRED EMBODIMENTS Exemplary embodiments of the present invention are described with respect to the figures. First Exemplary Embodiment: Fig. 1 is a vertical cross sectional view of a sealed type compressor in a first exemplary embodiment of the present invention. As shown in the figure, the sealed type compressor has a structure in which a compression mechanism 5 and a motor 6 to drive the compression mechanism 5 are disposed inside a sealed housing 4 which comprises an upper end plate 1, a cylindrical body section 2, and a lower end plate 3. Although details of the compression mechanism 5 are not shown, it can be of a rotary type or a scroll type. Electric power for the motor 6 is supplied from an external power supply (not shown) through a hermetic terminal 8 which is hermetically welded to a hole 7 provided on the upper end plate 1 of the sealed housing 4. A refrigerant is sucked through a suction pipe 9 (connecting pipe) that leads to a refrigerating circuit (not shown), compressed by the compression mechanism 5, discharged into the sealed housing 4 with a high pressure, and returned to the refrigerating circuit (not shown) through a discharge pipe 10 (connecting pipe). Accordingly, in this exemplary embodiment, the inside of the sealed housing 4 is filled with a high-pressure refrigerant, a structure so-called high-pressure type compressor. Fig. 2 is an enlarged view of the hermetic terminal 8 of the sealed type compressor shown in Fig. 1. The hermetic terminal 8 has on the top surface of a cup-shaped metal member 11 an electrically conducting pin 13 insulated by a glass seal 12. The bottom part of the cup-shaped metal member 11 has a skirt section 14 expanded like a skirt, with which the cup-shaped metal member 11 is hermetically welded to the hole 7 provided on a flat section of the upper end plate 1. A ring-shaped metal member 15 being a member to enhance rigidity (rigidity against deformation of the flat section) of the sealed housing 4 is welded to the outer periphery of the skirt section 14, which is inside the sealed housing 4, of the hermetic terminal 8 . The material of the ring-shaped metal member 15 is generally-available steel and its thickness is set to a value greater than 1/3 of the thickness of the upper end plate 1. To be more specific, in this exemplary embodiment, the thickness of the end plate 1 of the sealed housing 4 made of steel is chosen to be between 3 mm and 4 mm while the thickness of the ring-shaped metal member 15 is chosen to be between 1.5 mm and 5 mm. The width of the ring of the ring-shaped metal member 15 is chosen to be between 2 mm and 4 mm. The inner diameter of the ring-shaped metal member 15 is set to be greater than the outer diameter of the skirt section 14 of the hermetic terminal 8. Assembling by welding of the ring-shaped metal member 15 and the hermetic terminal 8 onto the upper end plate 1 is next described. At the location on the upper end plate 1 where the hermetic terminal 8 is to be disposed, a hole 7 slightly larger than the outer diameter of the cup-shaped metal member 11 is made on a surface (flat section) 16 with a relatively high degree of flatness. The ring-shaped metal member 15 is fixed by resistance welding to the outer periphery of the hole 7. Resistance welding is generally accomplished by concentrating an electric current by providing a protrusion on the part to be welded. However, in this exemplary embodiment, as resistance welding based on a protrusion produces dotted welds, it is not adopted because the ring-shaped metal member 15 will not suppress deformation of the upper end plate I of the sealed housing 4. Consequently, in this invention, a surface 1a of the ring-shaped metal member 15 which comes in contact with the upper end plate 1 is made flat with a relatively high degree of flatness, and is made in close contact with the flat section 16 of the upper end plate 1, and then resistance welding is carried out by allowing an electric current to flow. In this case, though rigidity increases as the width of the ring increases, the current density is not increased and thus the entire surface is not uniformly welded. Accordingly, the above-described range of width of 2 mm to 4 mm is adequate. By welding in this way, an arc-shaped welded joint is obtained, and the ring-shaped metal member 15 acts to suppress the deformation of the upper end plate 1. In the case of a ring-shaped metal member 15 with a large width or when welding without allowing too large an electric current to flow, a linear protrusion 18 is provided on the tip 17 of the ring-shaped metal member 15 as shown in Fig. 3. Although it is general practice to provide the linear protrusion 18 over the entire circumference, it may be good to divide into 3 or 4 arc sections. Evaluation of pressure resistance of the sealed housing 4 of the sealed type compressor of the present exemplary embodiment is next described. Generally, the pressure resistance requirement on a sealed housing of a refrigerant compressor is that it will not break when a static hydraulic pressure equal to 3 to 5 times the designed pressure value (maximum operating pressure) is applied, though a slight difference exists depending on standards and laws of different countries. When a static hydraulic pressure equal to 3 to 5 times the designed pressure value is gradually applied to inside the sealed housing 4 of this exemplary embodiment, the sealed housing 4 gradually swells, especially the upper end plate 1 swells in the shape of a sphere. In the absence of the ring-shaped metal member 15, the skirt section 14 of the hermetic terminal 8 fixed by welding to the flat section 16 will become part of a spherical surface and is forced inward with a strong force. Because of this force and the internal static hydraulic pressure, the glass seal 12 also tends to expand outwardly in the shape of a sphere thus exerting a large force on the sealing glass causing cracks in the glass and leakage of water. However, in this exemplary embodiment, although the flat section 16 (upper end plate 1) where the hermetic terminal 8 of the sealed housing 4 is welded tends to deform in the shape of a sphere, the ring-shaped metal member 15 fixed by welding to the flat section 16 of the sealed housing 4 suppresses the deformation, and also suppresses the skirt section 14 of the hermetic terminal 8 from being forced inwardly with a strong force, thereby preventing breakage of the glass seal 12. Consequently, a sealed housing 4 having a pressure-resistance strength high enough for a high-pressure refrigerant such as R410A containing HFC32 can be realized. Regarding the method of welding, although resistance welding was described in the foregoing, brazing may also be used with which the welded joint between the ring-shaped metal member 15 and the flat section 16 of the sealed housing 4 becomes an arc in shape. Also, even when the ring-shaped metal member 15 is not a perfect circular ring having some local cuts, or when a plurality of bow-shaped metal members are disposed encircling the weld of the hermetic terminal 8, they act to enhance the deformation rigidity of the sealed housing 4 exhibiting equivalent effect. Also, in preventing the deformation of the sealed housing 4 from exerting a large force to the glass seal 12 of the hermetic terminal 8, it is preferable to make the length of the weld to 1/4 of the circumference or greater, and the members to enhance the rigidity should preferably cover 2/3 or more of the total circumference of the weld of the hermetic terminal 8. Although the ring-shaped metal member 15 is welded to the inside of the sealed housing 4 (upper end plate 1) in the hermetic terminal of the above-described exemplary embodiment, it may be welded to the outside of the sealed housing 4 as shown in Fig. 4. In this case, welding of the ring-shaped metal member 15 and the hermetic terminal 8 is relatively easy. Furthermore, as a protecting frame member 19 for the hermetic terminal 8 is generally disposed on the outside of the sealed housing 4, assembling work becomes easy by welding it integrally with the hermetic terminal 8 as shown in Fig. 5. Also, the shape of the ring-shaped metal member 15 may be that of a burring-processed ring-shaped metal member 15a such as shown in Fig. 6 and Fig. 7. Also, though description of the material of the ring-shaped metal members 15, 15a was made with reference to steel, more pronounced rigidity effect may be obtained by the use of high-tension steel. Second Exemplary Embodiment: Figs. 8 to 10 illustrate a hermetic terminal section in a second exemplary embodiment of the present invention. As shown in Fig. 8, a hole 7 provided on an upper end plate I has a burring 20 formed toward the inside of a sealed housing 4. An end face 20a of the burring section 20 is processed into a flat surface, where a skirt section 14 of a hermetic terminal 8 is fixed by welding. In this exemplary embodiment, as the internal pressure of the sealed housing 4 increases, the sealed housing 4 gradually swells, and the upper end plate 1 swells in the shape of a sphere. However, as the rigidity of the burring 20 is large, it acts to suppress the deformation of its inner part, and prevents breakage of a glass seal 12 of the hermetic terminal 8. Furthermore, in this exemplary embodiment, as welding of the hermetic terminal 8 is possible even when the outer periphery of the hole 7 is made in the shape of a spherical surface, the deformation of the upper end plate 1 is reduced and the pressure-resistance strength of the upper end plate 1 can be improved. Also, the cost will be less compared with the afore-mentioned welding of the ring-shaped metal members 15 and 15a. Also, the hermetic terminal section shown in Fig. 9 has the above-mentioned burring 20 formed toward the outside of the sealed housing 4 (upper end plate 1). Similarly to the burring 20 formed toward the inside, rigidity of the peripheral edge of the hermetic terminal 8 is increased by the burring 20 making deformation difficult to take place, thus preventing breakage of the glass seal 12 and increasing the pressure-resistance strength. Deforming force exerted on the glass seal 12 is smaller when the burring 20 is formed on the outside than when it is formed on the inside. However, unless the flatness of the base part of the burring 20 is precisely obtained, welding with the hermetic terminal 8 becomes difficult. Also, the hermetic terminal section shown in Fig. 10 is obtained by welding the ring-shaped metal member 15a to the outer periphery of the burring 20 shown in Fig. 9, the welding of which providing further enhancement of the rigidity. Third Exemplary Embodiment: Fig. 11 shows a hermetic terminal section in a third exemplary embodiment of the present invention. A hermetic terminal 8 is hermetically welded to a doughnut-shaped flat plate 21 made of steel. The thickness of the flat plate 21 is set to be greater than an upper end plate 1 of a sealed housing 4. The flat plate 21 is hermetically welded to the upper end plate 1 with an overlap 22. The length of the overlap 22 is greater than the thickness of the upper end plate 1. When the overlap 22 is large, by welding both of the inner end 22a and the outer end 22b of the overlap of the flat plate 21 with the upper end plate 1, the rigidity can be further enhanced. In this exemplary embodiment, as the pressure inside the sealed housing 4 increases, the sealed housing 4 gradually swells, especially the upper end plate 1 swells in the shape of a sphere. However, as the overlap 22 between the doughnut-shaped flat plate 21 made of steel and the upper end plate 1 is fixed by welding, the thickness is increased and rigidity is increased, thus suppressing the deformation of the inner part and preventing breakage of a glass seal 12 of the hermetic terminal 8. As a result, it is possible to obtain a sealed housing 4 with a pressure-resistance strength high enough for a high-pressure refrigerant containing HFC32 such as R410a. Meanwhile, unless the thickness of the flat plate 21 is made greater than that of the upper end plate 1, the effect of preventing breakage of the glass seal 12 of the hermetic terminal 8 cannot be fully exhibited because the flat plate 21 itself deforms. Also, when the overlap 22 is small, the effect of preventing breakage of the glass seal 12 of the hermetic terminal 8 cannot be fully exhibited as bending takes place there. The length of the overlap 22 is required to be greater than the thickness of the upper end plate 1. It produces the same effect whichever of the upper end plate 1 and the flat plate 21 is welded inside. Fourth Exemplary Embodiment: Figs. 12 through 17 illustrate a connecting pipe section through which a refrigerant goes in and out in a fourth exemplary embodiment of the present invention. As shown in Fig. 12, a discharge pipe 10, being one of the connecting pipes through which the refrigerant goes in and out from a sealed housing 4, is fixed by welding to an upper end plate 1, followed by welding a ring-shaped metal member 23 on the outer periphery of the weld. When a pressure is applied to the inside of the sealed housing 4, the upper end plate 1 deforms in the shape of a sphere. In the absence of the ring-shaped metal member 23, a tensile stress concentrates at a brazed section 24 joining the discharge pipe 10 and the upper end plate 1, and fracture is caused. However, in this structure, even when the upper end plate 1 deforms in the shape of a sphere, the deformation in the vicinity of the weld of the discharge pipe 10 is suppressed and the tensile stress is eased, thus preventing leakage of the high-pressure refrigerant to outside due to fracture of the brazed section 24, and improving the pressure-resistance strength. Although the ring-shaped metal member 23 is welded to the inside of the sealed housing 4 in the above-described exemplary embodiment, it may be welded to the outside of the sealed housing 4 as shown in Fig. 13. Also, the shape of the ring-shaped metal member 23 may be that of the ring-shaped metal member 23a having a burring as shown in Figs. 14 and 15. Furthermore, by forming a burring 25 on the outer periphery of the weld of the upper end plate 1 and the discharge pipe 10, and welding the ring-shaped metal member 23a on the outer periphery of the burring 25, the rigidity may be further enhanced. Also, as connecting pipes are generally welded by copper brazing, assembling becomes easier by brazing the nearby ring-shaped metal members 23 and 23a at the same time. As set forth above, in the present invention, when the sealed housing 4 comprises the body section 2, the upper end plate 1 and the lower end plate 3, and the hermetic terminal 8 and the discharge pipe 10 are welded to the upper end plate 1, the invention is still more effective as the deformation of the upper end plate 1 is large. Also, the effect is more pronounced when used for a high-pressure refrigerant HFC32 or a high-pressure mixed refrigerant such as R410A containing HFC32. Fifth Exemplary Embodiment: Fig. 18 shows a connecting pipe section through which a refrigerant goes in and out in a fifth exemplary embodiment of the present invention. A small hole 26 having a diameter equal to or smaller than the inner diameter of a discharge pipe 10 being a connecting pipe is made on a flat section 16 of a sealed housing 4 (upper end plate 1), and the end face 10a of the discharge pipe is fixed by welding to the flat section 16 corresponding to the hole 26. As a method of welding, silver brazing may be adopted. However, a greater pipe strength may be obtained by employing diffusion welding in which an electric current is allowed to flow while a discharge pipe 10 made of copper, for instance, is being pressed to the flat section 16 thus making copper of the discharge pipe 10 diffuse into the sealed housing 4 because the temperature rise is smaller when compared with welding by brazing and the like. When a large pressure is applied to the inside of the sealed housing 4, the upper end plate 1 deforms in the shape of a sphere. If the position of the welded joint of the discharge pipe 10 is inside of the hole as in the prior art, a tensile stress in the direction of opening the welded joint is exerted by the spherical deformation of the upper end plate 1. However, since the position of the welded joint of the end face 10a of the discharge pipe is on the surface of the upper end plate 1 differently from the prior art, no crack and the like will be caused on the welded joint as no tensile stress is exerted, thus improving the pressure-resistance strength of the sealed housing 4. Also, the resistance to refrigerant flow may be reduced by expanding that end face 10a of the discharge pipe 10 which is on the side to be fixed by welding to the upper end plate 1 and by expanding the diameter of the hole 26 on the upper end plate 1. Sixth Exemplary Embodiment: Fig. 19 shows a connecting pipe section through which a refrigerant goes in and out in a sixth exemplary embodiment of the present invention. A small hole 26 having a diameter equal to or smaller than the inner diameter of a discharge pipe 10 is made on a flat section 16 of a sealed housing 4 (upper end plate 1). A recessed section 28 having a diameter equal to or slightly larger than the outer diameter of the discharge pipe 10 is made on the periphery of the hole 26, into which the discharge pipe end section 10b is inserted, and both the outer periphery of the discharge pipe end section 10b and the discharge pipe end face 10a are fixed by brazing and the like. In the above structure, when a large pressure is applied to the inside of the sealed housing 4, the upper end plate 1 is deformed in the shape of a sphere. If the position of the welded joint of the discharge pipe 10 is inside the hole as in the prior art, a tensile stress in the direction of opening the welded joint is exerted by the spherical deformation of the upper end plate 1. In the above structure, however, as the position of the welded joint is at both the outer periphery of the discharge pipe end section 10b and the discharge pipe end face 10a, even though a tensile stress is exerted to the outer periphery of the discharge pipe end section 10b, a crack will not extend to the weld of the discharge pipe end face 10a thus maintaining hermeticity. Also, when a force is exerted to the discharge pipe 10, though a bending stress is exerted to the weld, the outer periphery of the discharge pipe end section 10b inserted in the recessed section 28 supports it, thus relieving the discharge pipe end face 10a from the tensile stress and providing enough strength to the welded joint. In the fifth and sixth exemplary embodiments, when a structure in which the sealed housing comprises a body section and upper and lower end plates is used to welding of a hermetic terminal and one of the connecting pipes to one of the end plates, one of the end plates will have two or more holes causing larger deformation. Therefore, employment of the above-described method of welding will be further effective. Also, when applied to refrigerants in general such as R22 and the like, cost reduction may be possible by reducing the thickness of the sealed housing or the grade of its material. When applied to high-pressure refrigerants such as HFC32 or R410A containing HFC32, the pressure resistance of the sealed housing may be more effectively improved. As has been described in the foregoing exemplary embodiments, in the present invention, a member to enhance rigidity of the sealed housing is welded to the sealed housing encircling the weld of the hermetic terminal. Consequently, even when the inside of the sealed housing becomes high in pressure and the sealed housing to which the hermetic terminal is welded is deformed, the member to enhance the rigidity of the outer periphery of the weld of the hermetic terminal suppresses the deformation of the hermetic terminal and prevents breakage of the glass seal of the hermetic terminal, thus realizing a sealed type compressor having a high pressure resistance. Also, by resistance welding the ring-shaped metal member to the sealed housing, the entire area of the ring-shaped metal member can be fixed by welding to the sealed housing, thus deformation of the end plates can effectively suppress deformation of the hermetic terminal and a sealed type compressor with a high pressure-resistance strength can be realized. Also, in this invention, by providing a burring-processed hole on the sealed housing and hermetically welding the hermetic terminal to the hole, deformation of the periphery of the hermetic terminal is made difficult to take place because of the burring, thus preventing breakage of the glass seal and improving the pressure-resistance strength. Also, in this invention, the hermetic terminal is once hermetically welded to a plate material followed by hermetically welding the plate material to the sealed housing with an overlap. As a result, in the event the inside of the sealed housing becomes high in pressure and the end plate to which the hermetic terminal is welded deforms, it is possible to suppress the deformation of the hermetic terminal as the rigidity of the overlap is large and to prevent breakage of the glass seal of the hermetic terminal thus realizing a sealed type compressor having a large pressure-resistance strength. The invention is especially effective in a structure in which a sealed housing comprises a body section and end plates closing an opening of the body section, and a hermetic terminal is hermetically welded to an end plate. Also, in this invention, by welding a ring-shaped metal member on the outer periphery of the weld of the connecting pipes (discharge pipe and suction pipe), the tensile stress produced in the weld by the deformation of the sealed housing due to internal pressure of the connecting pipes is reduced, and the pressure-resistance strength of the joints of the connecting pipes is improved. Furthermore, by brazing both the connecting pipes and the ring-shaped metal member, assembling becomes easy. Also, in this invention, a hole having a diameter equal to or smaller than the inner diameter of a connecting pipe is made on a flat section of the sealed housing and end face of the connecting pipe is fixed by welding to the outside surface of the sealed housing. As a result, in the event a high pressure is exerted to the inside of the sealed housing, no large tensile stress is exerted to the weld thus the pressure-resistance strength of the sealed housing is improved. The invention also provides a recessed section in the periphery of a hole on the sealed housing into which an end portion of a connecting pipe is inserted and fixed by welding. By fixing by welding both the end face of the connecting pipe and the outer periphery of the end portion, in the event a large force is exerted to the pipe, breakage is hard to take place as welded joints exist at two locations facing different directions, thus improving pressure-resistance strength of the sealed housing and providing a sealed type compressor with a strength high enough to withstand a large force that may be exerted to the pipes. Also, when the sealed housing comprises a body section and end plates and a hermetic terminal and connecting pipes are welded to the end plates, the invention is further effective as the deformation of the end plates is large. When practiced with a high-pressure refrigerant HFC32 or a refrigerant containing HFC32, the effect of the invention is more pronounced.

Claims: A sealed type compressor comprising: a sealed housing (4) wherein a motor (6) and a compression mechanism (5) to be driven by said motor are disposed; and a hermetic terminal (8) hermetically welded to said sealed housing for supplying power to said motor from outside said sealed housing; said hermetic terminal comprising: a cup-shaped metal member (11); an electrically conducting pin (13); and a glass seal (12) to insulate between said cup-shaped metal member and said electrically conducting pin; wherein means is provided around said hermetic terminal to enhance rigidity against deformation of said sealed housing. The sealed type compressor according to Claim 1 wherein said rigidity enhancing means comprises a member welded to encircle the welded joint between said sealed housing and said hermetic terminal. The sealed type compressor according to Claim 2, wherein said member to enhance rigidity against deformation of said sealed housing is a ring-shaped metal member (15). The sealed type compressor according to Claim 3, wherein the thickness of said ring-shaped metal member (15) is greater than 1/3 of the thickness of said sealed housing. The sealed type compressor according to Claim 3, wherein the weld at which said ring-shaped metal member is welded to said sealed housing is an arc in shape. The sealed type compressor according to Claims 3, 4 or 5 wherein said ring-shaped metal member is welded to the inside of said sealed housing. The sealed type compressor according to Claims 3, 4 or 5 wherein said ring-shaped metal member is welded to the outside of said sealed housing. The sealed type compressor according to Claim 7, wherein said ring-shaped metal member is welded into one piece with the protecting frame member of said hermetic terminal. The sealed type compressor according to any one of Claims 3 to 5, wherein said ring-shaped metal member is fixed to said sealed housing by a resistance weld. The sealed type compressor according to Claim 9, wherein the width of said ring-shaped metal member is not greater than 4 mm and said resistance weld does not have a protrusion in the welded joint. The sealed type compressor according to Claim 9, wherein said resistance weld includes a linear protrusion in the welded joint. The sealed type compressor according to Claim 1 wherein said rigidity enhancing means comprises burring (20) provided around a hole (7) provided in said sealed housing to which said hermetic terminal is hermetically welded. The sealed type compressor according to Claim 12, wherein said burring is provided toward the inside of said sealed housing. The sealed type compressor according to Claim 12, wherein said burring is provided toward the outside of said sealed housing. The sealed type compressor according to Claim 1 wherein said rigidity enhancing means comprises a plate member (21) to which said hermetic terminal is hermetically welded and said plate member being hermetically welded to said sealed housing with an overlap therebetween. The sealed type compressor according to Claim 15, wherein the thickness of said plate member to which said hermetic terminal is to be welded is greater than the thickness of said sealed housing. The sealed type compressor according to Claim 15, wherein the length of the overlap between said plate member and said sealed housing is greater than the thickness of said sealed housing. The sealed type compressor according to any one of Claims 1 to 5, 8 or 10 to 17, wherein said sealed housing comprises a body section and an end plate section to close an opening of said body section, and said hermetic terminal is hermetically welded to said end plate section. A sealed type compressor according to claim 1, further comprising a connecting pipe connecting the inside and the outside of said sealed housing and through which a refrigerant goes in and out fixed by welding to said sealed housing, and a ring-shaped metal member (23) welded around the outer periphery of the weld. The sealed type compressor according to Claim 19, comprising burring around a hole in said sealed housing to which said connecting pipe is welded. The sealed type compressor according to Claims 19 or 20, wherein said connecting pipe and said ring-shaped metal member are brazed to said sealed housing.

Inventors: MURAMATSU SHIGERU, NIIHARA OSAMI, ONO MAMORU, TAKANO HIROSHI, MURAMATSU, SHIGERU, NIIHARA, OSAMI, ONO, MAMORU, TAKANO, HIROSHI
Applicants: MATSUSHITA ELECTRIC IND CO LTD, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Application year: 1998
Main classification: F04C29
IPC codes: F04C23, F04B39