JP2014029136A - Displacement type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deterioration of fixing strength between a frame and a sealed container by preventing hardening of welded metal and generation of a gas due to transfer of carbon in the frame to a welded portion.SOLUTION: A displacement type compressor includes: a compressing mechanism portion; a motor portion for driving the compressing mechanism portion; a crank shaft for transmitting rotation of the motor portion to the compressing mechanism portion; and a sealed container 21 accommodating the compressing mechanism portion, the motor portion and the crank shaft. The compressing mechanism portion has a frame 12 having a bearing for supporting the crank shaft, and the frame is fixed to the sealed container through several welded portions. The welded portions between the frame and the sealed container are formed by inserting inclusions 24 of an iron-based material of a small content of carbon into through holes 22 formed on the sealed container in advance, and welding the same.

Description

  The present invention relates to a positive displacement compressor used for applications such as a refrigerant compressor for refrigeration and air conditioning and an air compressor, and is particularly suitable for a hermetic refrigerant compressor for refrigeration and air conditioning.

  As this type of positive displacement compressor, there is a hermetic scroll compressor or the like. There are things that have been.

  The thing of the said patent document 1 is accommodated in the cylindrical airtight container to which the discharge pressure of a refrigerant | coolant acts, The airtight type fluid machine provided with the latching structure for fixing a to-be-fixed member to this airtight container ( Positive displacement compressors) are described. Further, the locking structure is formed by inserting an interposed member such as a steel ball or a cylindrical member into a through-hole provided at a position where the fixed member of the sealed container exists, and by overlay welding from above the interposed member. In addition to closing the through hole, the interposition member presses and locks the frame.

  According to the one described in Patent Document 1, the locking structure is configured to close the through hole by build-up welding from above the interposition member, and thereby the fixed member is made only by a welding material. It is described that the welding heat transmitted to the frame can be reduced as compared with the case where the frame is fixed to a sealed container, the frame is prevented from being deformed by the welding heat, and the efficiency of the sealed fluid machine is prevented from being lowered. ing.

  Further, in Patent Document 2, a compression mechanism part and an electric motor part are accommodated in a cylindrical sealed container on which discharge pressure acts, and either the compressor part or the electric motor part, or both, A hermetic rotary compressor (displacement compressor) that is fixed to a container by scissor welding (tack welding) is described. A countersink-shaped recess is formed in advance in the portion of the outer peripheral surface of the sealed container cylindrical portion that is countersunk, and the compression mechanism is disposed on the inner surface of the sealed container in which the recess is formed. As described above, it is described that the above-described saddle welding is performed.

  According to this Patent Document 2, the welding time can be shortened and thermal deformation of the parts to be welded can be prevented as compared with the case where the part to be welded of the sealed container cylindrical part is subjected to the saddle welding without processing. In addition, compared to the case where a through-hole is provided in the part to be welded, the drilling time can be shortened, and deburring work is not required, so the processing cost can be reduced and the reliability against leakage of the welded part is improved. It describes what you can do.

JP 2009-2222052 A JP 2006-226242 A

  The positive displacement compressor as described above includes a compression mechanism section that performs a compression operation, an electric motor section that drives the compression mechanism section, and a crankshaft that transmits the rotation of the electric motor section to the compression mechanism section. Etc. The compression mechanism section includes a frame that supports the crankshaft via a bearing, and the rotation operation of the electric motor section is transmitted to the compression mechanism section via the crankshaft, thereby compressing the compression mechanism section. Operation is realized.

  In many cases, the frame is joined and fixed to the sealed container by plug welding, tack welding, or the like. Since cast iron is generally used as the material of the frame, it contains a large amount of carbon. Therefore, during the welding, the carbon of the frame moves to the weld and hardens the weld (welded metal), Cracks are likely to occur. Further, a large amount of carbon contained in the cast iron easily reacts with oxygen during welding to generate CO gas and the like, and voids are easily generated between the frame and the weld metal.

  For this reason, cracks are likely to be generated from the gap generated between the frame and the weld metal, or the gap generated inside the weld metal, and there is a concern that the strength for fixing the frame to the sealed container is reduced. The

  In the thing of the said patent document 1, it is trying to prevent the thermal deformation of the to-be-fixed member (frame) by welding heat by providing an interposition member in the through-hole formed in the airtight container, but a crack is in a welding part. No consideration has been given to the occurrence and reduction of the fixing strength of the frame.

  Further, in the above-mentioned Patent Document 2, a countersink-shaped recess is formed in advance in a sealed container so as to perform spot welding, thereby shortening the welding time and preventing thermal deformation of the parts to be welded, Although the drilling time is shortened, the thing of this patent document 2 is not considered about the crack generate | occur | producing in a welding part and reducing the fixed strength of a flame | frame.

  The object of the present invention is to suppress the fixing strength between the frame and the sealed container by suppressing carbon from moving to the welded portion and hardening the welded portion (welded metal) or generating gas. The object is to obtain a positive displacement compressor capable of suppressing the above.

  To achieve the above object, the present invention provides a compression mechanism section, an electric motor section for driving the compression mechanism section, a crankshaft for transmitting the rotation of the electric motor section to the compression mechanism section, and the compression A mechanism part, an electric motor part, and a sealed container that accommodates the crankshaft, and the compression mechanism part has a frame provided with a bearing for supporting the crankshaft, and the frame is welded to the sealed container at several locations. A displacement type compressor that is fixed by a portion, wherein a weld portion between the frame and the sealed container inserts an inclusion of an iron-based material with a low carbon content into a through-hole previously formed in the sealed container It is characterized by having a welded configuration

  According to the present invention, the welded portion between the frame and the sealed container is configured to insert inclusions with a low carbon content into the through holes formed in the sealed container in advance, so that the carbon of the frame is welded. Is difficult to move to the welded part, which can harden the welded part (welded metal) and suppress the generation of gas, and the volume that can suppress the reduction in the fixing strength between the frame and the sealed container. A shape compressor can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing a first embodiment of a positive displacement compressor according to the present invention. It is a principal part enlarged view which expands and shows the A section of FIG. 1, and is a figure which shows the state which inserts an inclusion in the through-hole formed in the airtight container. The expanded sectional view of the inclusion shown in FIG. It is a principal part enlarged view which expands and shows the A section of FIG. 1, and is a figure which shows the state after inserting and welding an inclusion to the through-hole formed in the airtight container. FIG. 5 is a diagram illustrating a second embodiment of the positive displacement compressor according to the present invention and corresponding to FIG. 2. The expanded sectional view of the inclusion shown in FIG. It is a figure which shows the state after inserting and welding an inclusion in the through-hole formed in the airtight container, and is a figure equivalent to FIG. It is a principal part enlarged view which shows the state before welding of the conventional positive displacement compressor, and is a figure equivalent to FIG. It is a principal part enlarged view which shows the state after welding of the conventional positive displacement compressor, and is a figure equivalent to FIG.

  Hereinafter, specific embodiments of the positive displacement compressor of the present invention will be described with reference to the drawings. In each figure, the part which attached | subjected the same code | symbol has shown the part which is the same or it corresponds.

Example 1 of the positive displacement compressor of the present invention will be described with reference to FIGS.
FIG. 1 is a longitudinal sectional view showing the overall structure of a positive displacement compressor of this embodiment. In this embodiment, an example in which the present invention is applied to a hermetic scroll compressor will be described.

  A hermetic scroll compressor (displacement compressor) 1 includes a compression mechanism unit 2, an electric motor unit 3 for driving the compression mechanism unit 2, and rotation of the electric motor unit 3 in the hermetic container 21. The crankshaft 11 and the like for transmission to the housing 2 are accommodated.

  The compression mechanism portion 2 includes a frame 12 provided with a main bearing (bearing) 14 for supporting the main shaft portion 11a of the crankshaft 11, and the frame 12 has an outer periphery as shown in A portion. The surface is fixed at several places in the circumferential direction by welds welded to the sealed container 21 (plug welding in this embodiment). Further, the compression mechanism unit 2 has a non-orbiting scroll 19 and an orbiting scroll 20 that meshes with the non-orbiting scroll 19 and performs an orbiting motion. The non-orbiting scroll 19 is fixed to the frame 12, the suction pipe 6 is connected to the outer peripheral side thereof, and the discharge port 4 is provided at the center.

  A boss portion 20a is formed on the back surface of the orbiting scroll 20, and the eccentric pin portion 11b of the crankshaft 11 is engaged with the boss portion 20a so that the orbiting scroll 20 is orbited. An Oldham ring 29 is provided between the back of the orbiting scroll 20 and the frame 12 to prevent the orbiting scroll 20 from rotating.

  When the non-orbiting scroll 19 and the orbiting scroll 20 are engaged with each other and revolving, a gas such as a refrigerant sucked into the suction chamber 19a on the outer peripheral side of the non-orbiting scroll 19 from the suction pipe 6 is converted into the two scrolls 19, While being compressed by the compression chamber formed by 20, it moves to the center side and is discharged from the discharge port 4 to the discharge space 5 a formed in the upper part of the sealed container 21. Thereafter, the compressed gas flows through a passage (not shown) formed by the inner peripheral surface of the sealed container 21 and the outer peripheral surface of the compression mechanism unit 2 into the discharge space 5b on the motor unit 3 side, The oil mixed in the compressed gas is separated and discharged from the discharge pipe 7 to the refrigeration cycle or the like.

  The separated oil is stored in the oil reservoir 18 below the sealed container 21. The oil in the oil reservoir 18 is supplied to sliding portions such as the main bearing 14 and the eccentric pin portion 11b by an oil supply pump 30 attached to the lower end of the crankshaft 11. Reference numeral 10 denotes an oil drain pipe for guiding the oil after being supplied and lubricated to the main bearing 14, the eccentric pin portion 11 b, and the like to the oil reservoir 18.

  The auxiliary shaft portion 11 c below the crankshaft 11 is supported by an auxiliary bearing 15. The sub-bearing 15 is provided in a sub-bearing housing 16, and the sub-bearing housing 16 is attached to a sub-frame 13 that is welded and fixed to the sealed container 21 by plug welding or the like. The auxiliary bearing 15 is also configured so that the oil in the oil reservoir 18 is supplied via the oil supply pump 30.

  The electric motor unit 3 includes a stator 8 and a rotor 9, and the stator 8 is fixed to the inner peripheral surface of the hermetic container 21, and the rotor 9 is fixed to the crankshaft 11. The electric motor unit 3 is driven by an electric input from an inverter (not shown) via an electric terminal 17, and the rotation of the rotor 9 is performed by the rotation of the compression mechanism unit 2 via the crankshaft 11. The scroll 20 is turned.

  In this embodiment, as shown in part A of FIG. 1, the outer peripheral surface of the frame 12 is welded and fixed to the hermetic container 21 at several locations in the circumferential direction by plug welding. Before describing the configuration of the present embodiment, the configuration of a conventional plug welded portion will be described with reference to FIGS. 8 and 9 for comparison. FIG. 8 is an enlarged view of a main part showing a state before welding of a plug welded part in a conventional positive displacement compressor, and FIG. 9 is an enlarged view of a main part showing the state after welding.

As shown in FIG. 8, before the welding of the plug welded portion, a through hole 22 for plug welding is provided in advance in the sealed container 21 at a position corresponding to a place where the frame 12 is plug welded. The position of the through hole 22 is welded by arc welding or the like to fix the frame 12 to the sealed container 21 and close the through hole 22 with a weld metal.
FIG. 9 shows a state after the frame 12 and the sealed container 21 are plug-welded. By performing plug welding, the frame 12 and the sealed container 21 are joined and fixed by the weld metal 23.
By the way, cast iron (for example, FC250 gray cast iron) is used as the material of the frame 12, but the cast iron contains a lot of carbon (about 2 to 7%). For this reason, the carbon of cast iron moves to the weld metal and melts during welding, and the hardness of the weld metal is increased, and the ductility and toughness are hindered and cracking is likely to occur. Further, since cast iron contains a large amount of carbon, it is oxidized by oxygen during welding to become CO gas, which causes voids between the weld metal and the base metal (frame) or in the weld metal. . In addition, cast iron is prone to whitening when exposed to air from the molten state, and when whitened, the thermal expansion coefficient is significantly different from that of gray cast iron. Therefore, shrinkage between the weld and the base material (frame). In addition, white birch is hard and brittle, so cracks are likely to occur.

For this reason, as shown in FIG. 9, in the plug welded portion in the conventional positive displacement compressor, a gap (gap) 28 is formed between the weld metal 23 and the frame 12, and the weld metal 23 is further melted with carbon. Due to curing by the above-mentioned and whitening described above, cracks 29 are generated starting from the gaps 28, and the compressed gas inside the sealed container 21 may leak from these gaps 28 and cracks 29. I found out.
Moreover, since the intensity | strength which fixes the flame | frame 12 to the airtight container 21 will fall when a space | gap and a crack generate | occur | produce in the said weld part, the reliability of a positive displacement compressor is reduced.

Therefore, in the positive displacement compressor of this embodiment, the plug welded portion is configured as shown in FIGS.
FIG. 2 is an enlarged view of a main part showing the A part of FIG. 1 in an enlarged manner, and shows a state in which the inclusion 24 is inserted into the through hole 22 formed in the sealed container 21. That is, also in this embodiment, since the frame 12 is plug-welded to the sealed container 21 as in the prior art, the process is the same until the through hole 22 is formed at the welding target portion of the sealed container 21. . Conventionally, from this state, plug welding is directly performed so as to close the through hole 22, but in this embodiment, before the plug welding is performed, an iron-based material having a low carbon content is formed in the through hole 22. After the inclusion 24 is inserted, plug welding is performed so as to close the through hole 22 by arc welding or the like.

  As shown in the enlarged sectional view of FIG. 3, the inclusion 24 has a cylindrical portion 24 a and a bottom member 24 b that closes one end of the cylindrical portion 24 a. Further, as the material of the inclusion 24, an iron-based material having a carbon content of 0.3% or less and having a small quenching hardening or a negligible value is used. Preferably, mild steel having a carbon content of 0.25 to 0.1% may be used. For example, it is preferable to use mild steel such as S25C or S15C of carbon steel for mechanical structure, SS400 of general structural rolled steel.

  In the example shown in FIG. 3, a cylindrical member whose one end is closed is used as the inclusion 24. However, the present invention is not necessarily limited to this shape. Even if inclusions such as those composed only of the member corresponding to the bottom member 24b are used, substantially the same effect can be obtained. However, preferably, if the inclusion composed of the cylindrical portion 24a and the bottom member 24b as shown in FIG. 3 is used, the inclusion 24 can be kept in a stable posture after being inserted into the through hole 22. Therefore, the effect that a welding operation can be performed easily is obtained.

  FIG. 4 is an enlarged view of the main part showing the portion A of FIG. 1 in an enlarged manner as in FIG. 2, and shows a state after the inclusion 24 is inserted into the through hole 22 formed in the sealed container 21 and plug-welded. FIG. By providing the inclusions 24 and performing plug welding, the inclusions are also melted during welding, and the frame 12 and the sealed container 21 in contact with the inclusions are also melted, whereby the frame 12 is sealed. The through hole 22 is fixed to the container 21 and further closed with a weld metal. Further, since the inclusion 24 is provided for welding, the inclusion 24 can suppress the carbon contained in a large amount in the cast iron frame 12 from moving to the weld metal 23 and being melted. Thereby, the hardness of the weld metal 23 can be increased, and the ductility and toughness can be inhibited to prevent cracks from being easily generated.

In addition, since carbon contained in a large amount in the frame 12 made of cast iron can be suppressed from coming into contact with oxygen in the air during welding, generation of CO gas can be suppressed, and between the frame 12 and the weld metal 23 can be suppressed. It is also possible to suppress the formation of voids in the weld metal.
Further, although the cast iron frame 12 is melted during welding, contact with air is suppressed by the inclusions 24, so that it is possible to suppress whitening due to contact with air from the melted state. Therefore, the difference in thermal expansion during contraction between the welded portion 23 and the frame 12 can be reduced, and cracks and voids can be suppressed from this point.

  Therefore, according to the present embodiment, it is possible to suppress the occurrence of a gap between the frame 12 and the weld metal 23 or in the weld metal, and further suppress the hardening of the weld metal 23 to improve ductility and toughness. Therefore, it is possible to prevent cracks from being generated starting from the voids, and the compressed gas inside the sealed container 21 from leaking from these voids and cracks.

  Further, the fixing strength of the frame 12 can be increased by not causing the cracks or the like in the welded portion. As a result, since the support rigidity of the crankshaft 11 by the main bearing 14 and the support rigidity of the non-orbiting scroll 19 can be ensured, a highly reliable positive displacement compressor can be obtained.

  Second Embodiment A positive displacement compressor according to a second embodiment of the present invention will be described with reference to FIGS. 5 is a view corresponding to FIG. 2, FIG. 6 is an enlarged sectional view of the inclusion shown in FIG. 5, and FIG. 7 is a view showing a state after the inclusion is inserted into a through hole formed in the sealed container and welded. FIG. 5 is a diagram corresponding to FIG. 4. The difference between the second embodiment and the first embodiment will be described with reference to these drawings. Note that the portions denoted by the same reference numerals as those in FIGS.

  The second embodiment is different from the first embodiment in that, as shown in FIG. 5, a recessed portion 25 is provided in advance in a portion (welded portion) of the frame 12 to be plug-welded and formed in the sealed container 21. An inclusion (hereinafter referred to as a convex inclusion) 26 having a cylindrical portion and a convex bottom member for fitting into the concave portion 25 is inserted so as to straddle the through hole 22 and the concave portion 25. Thereafter, plug welding is performed. FIG. 5 shows a state before plug welding, and 27 is a press-fitting member for press-fitting the convex inclusion 26 into the through-hole 22 and the concave portion 25.

  FIG. 6 is an enlarged view of the convex inclusion 26 shown in FIG. 5 and shows the shape before the frame 12 is plug welded to the sealed container 21, and the material of the convex inclusion 26 is also the first embodiment. In the same manner as above, it is made of an iron-based material having a low carbon content. In the inclusion 24 (see FIG. 3) shown in the first embodiment, the bottom member 24b that closes one end of the cylindrical portion 24a is formed in a disc shape. However, the inclusion 26 in the second embodiment is a cylinder. A portion 26a and a bottom member 26b that closes one end of the cylindrical portion 26a are formed, and the bottom member 26b is formed in a convex shape. By inserting the inclusion 26 having such a convex portion into the through hole 22 and the recess 25 using the press-fitting member 27 shown in FIG. 5, the inclusion is formed as shown in 26 of FIG. It press-fits while deforming into a shape along the shape of the through hole 22 and the recess 25.

  FIG. 7 shows a state in which the convex inclusion 26 is plug welded after being press-fitted into the through hole 22 and the concave portion 25. 23 is a weld metal, and the inclusion 26 is melted at the time of plug welding. The frame 12 and the sealed container 21 in contact with the inclusion 26 are also melted, and the frame 12 is fixed to the sealed container 21. Is done. The through hole 22 is also closed by the weld metal 23.

  According to the second embodiment, the same effect as in the first embodiment is obtained, and the inclusion 26 is press-fitted and welded, so that the carbon contained in the cast iron frame 12 is transferred to the weld metal 23. It is possible to suppress the generation of CO gas by moving to harden the weld metal, or the carbon touching oxygen in the air during welding, and further suppressing the whitening of the welded portion. Therefore, it is possible to suppress the generation of voids between the frame 12 and the weld metal 23 or in the weld metal, or the occurrence of cracks in the weld metal 23.

  Furthermore, according to the present embodiment, before the welding, the convex inclusion 26 is press-fitted into the concave portion 25 and is welded in a temporarily fixed state. Therefore, the positioning operation of the frame 12 and the sealed container 21 performed before welding is performed. The positioning accuracy of the frame 12 and the sealed container 21 can be improved. As a result, the reliability of the positive displacement compressor 1 can be further improved.

As described above, according to each embodiment of the present invention, the welded portion between the frame 12 and the sealed container 21 is made of an iron-based material having a low carbon content in the through-hole 22 formed in the sealed container 21 in advance. Since the configured inclusion 24 is inserted and then welded, the carbon of the frame 12 becomes difficult to move to the weld metal 23, thereby hardening the weld metal 23 and generating gas. It is possible to suppress the formation of voids between the frame 12 and the weld metal 23 or in the weld metal.
Therefore, since it can suppress that the crack (crack) generate | occur | produces in the weld metal 23 from the said clearance gap, and it can suppress that the fixed strength of the flame | frame 12 and the airtight container 21 falls, a reliable positive displacement compressor There is an effect that can be obtained.

1: positive displacement compressor, 2: compression mechanism, 3: electric motor, 4: discharge port,
5a, 5b: discharge space,
6: suction pipe, 7: discharge pipe,
8: Stator, 9: Rotor,
10: Oil drain pipe,
11: Crank shaft, 11a: Main shaft portion, 11b: Eccentric pin portion, 11c: Sub shaft portion,
12: frame, 13: subframe,
14: main bearing, 15: auxiliary bearing, 16: auxiliary bearing housing,
17: Electric terminal, 18: Oil sump,
19: non-orbiting scroll, 20: orbiting scroll,
21: closed container,
22: Through hole, 23: Weld metal,
24, 26: inclusions, 24a, 26a: cylindrical portions, 24b, 26b: bottom members,
25: recess, 27: press-fit member,
28: gap, 29: crack,
30: Refueling pump.

Claims (9)

A compression mechanism unit, an electric motor unit for driving the compression mechanism unit, a crankshaft for transmitting rotation of the electric motor unit to the compression mechanism unit, and the compression mechanism unit, the electric motor unit, and the crankshaft are accommodated A sealed container,
The compression mechanism section has a frame provided with a bearing for supporting the crankshaft, and is a positive displacement compressor in which the frame is fixed to the sealed container by several welds,
The welded portion between the frame and the sealed container is a configuration in which an inclusion of an iron-based material having a low carbon content is inserted into a through-hole previously formed in the sealed container and welded. Compressor.   2. The positive displacement compressor according to claim 1, wherein the inclusion is made of an iron-based material having a carbon content of 0.3% or less and having a small quenching hardening or can be ignored. Positive displacement compressor.   It is a positive displacement compressor of Claim 2, Comprising: The said inclusion is comprised with 0.25-0.1% of mild steel for carbon containing, The positive displacement compressor characterized by the above-mentioned.   3. The positive displacement compressor according to claim 2, wherein the inclusion includes a cylindrical portion and a bottom member that closes one end of the cylindrical portion.   3. The positive displacement compressor according to claim 2, wherein the inclusions are disk-shaped.   The positive displacement compressor according to claim 2, wherein a recessed portion is provided in advance in a portion to be welded of the frame, and the inclusion includes a cylindrical portion and a bottom member that closes one end side of the cylindrical portion. And the bottom member is formed in a convex shape so as to be fitted into the concave portion.   The positive displacement compressor according to claim 6, wherein the inclusion is press-fitted into the through hole and the concave portion and inserted and then welded.   8. The positive displacement compressor according to claim 1, wherein the frame is fixed to the sealed container by plug welding.   The positive displacement compressor according to claim 8 is a hermetic scroll compressor having a non-orbiting scroll and an orbiting scroll that meshes with the non-orbiting scroll in the compression mechanism section. Positive displacement compressor.

Images