JP5506269B2 - Hermetic electric compressor - Google Patents

Description

  The present invention relates to a hermetic electric compressor used in a refrigeration cycle apparatus.

  Patent Document 1 is known as a conventional hermetic electric compressor. FIG. 4 is a longitudinal sectional view of a rotary compressor showing a hermetic compressor. This is FIG. 1 itself of Patent Document 1, but the code is changed. In FIG. 4, 1 is an airtight container, which houses an electric element in the upper part and a compression element in the lower part. Reference numeral 2a denotes a stator, and the connection between the stator 2a and the hermetic container 1 is fixed to the welded portion 12 through a gap. The technique disclosed in Patent Document 1 is a technique aiming at noise reduction, and “the connection between the welded portion 4 and the stator 2 is close to a point contact via the gap 4 a, and the outer peripheral surface of the stator 2. Is almost lifted from the case 1, so that the vibration transmission area can be greatly reduced and the vibration transmission to the case 1 can be reduced. "

JP-A-62-199974

In the rotary compressor shown in Patent Document 1 described above, a gap exists between the stator and the hermetic container, so that the outermost peripheral diameter of the stator is set smaller than the outermost peripheral diameter of the compression mechanism section. The volume of the stator iron core cannot be increased as much as possible, and the space set for the winding in the stator core cannot be increased accordingly. Also, in order to enlarge them, when the outermost peripheral diameter of the stator is set to be equal to or larger than the outermost peripheral diameter of the compression mechanism, and the stator is fixed in the closed container by shrink fitting or press fitting There is a problem that the stress applied to the stator iron core increases and the iron loss increases. In shrink fitting and press fitting, when adjusting the tightening allowance between the stator and the airtight container, it is necessary to take into account that the shape change of the stator iron core requires a mold change, and therefore it takes cost and time. .

  In recent years, there has been a demand for improving the efficiency of electric devices from the viewpoint of energy saving. Iron loss, which is a loss generated in the stator inside the compressor, occupies a relatively large specific gravity, and there is still room for improvement in this regard.

  An object of this invention is to provide the compressor with few iron losses.

The object of the present invention is as follows.
In a hermetic type electric compressor having an electric motor composed of a stator and a rotor and a compression mechanism driven by the electric motor in a hermetic container,
The stator has a core back;
The sealed container has an enlarged diameter part whose diameter is enlarged at the step part,
The enlarged diameter portion is provided in a portion corresponding to the axial length of the stator,
The enlarged diameter portion and the core back are fixed by welding,
In the sealed container, the stator is inserted by an intermediate fit ,
The position where the welding is performed is a central portion of the stator,
The stator is achieved by not contacting the stepped portion .

  ADVANTAGE OF THE INVENTION According to this invention, a compressor with little iron loss can be provided.

It is sectional drawing of a vertical scroll compressor. It is an enlarged view of an electric motor part. It is sectional drawing of a stator and an airtight container enlarged diameter part. It is a longitudinal cross-sectional view of the conventional hermetic electric compressor. It is an enlarged view of a stator and an airtight container enlarged diameter part. It is an enlarged view of a stator and an airtight container enlarged diameter part. It is an enlarged view of a stator and an airtight container enlarged diameter part. It is an enlarged view of a stator and an airtight container enlarged diameter part. It is an enlarged view of a stator and an airtight container enlarged diameter part. It is a comparison figure of motor efficiency.

  Embodiments of the present invention will be described below with reference to the drawings.

  The first embodiment will be described with reference to FIGS. FIG. 1 is a sectional view of a vertical scroll compressor. As a main configuration, an electric motor 2 that is an electric element, and a compression mechanism 3 that is an electric element that compresses the refrigerant between an orbiting scroll 13 and a fixed scroll 14 driven by the electric motor 2 are provided inside the sealed container 1. And an Oldham ring as a rotation restricting member that supports and guides the orbiting scroll 13 between the fixed scroll 14 and the fixed member 16 so that the orbiting scroll 13 rotates without rotating relative to the fixed scroll 14. 15. The electric motor 2 includes a stator 2a and a rotor 2b. The stator 2a is fixed to the hermetic container 1 and the rotor 2b is press-fitted and fixed to the shaft 8.

  The compression mechanism 3 is configured by meshing the fixed scroll 14 and the orbiting scroll 13 as in the prior art, and the orbiting scroll 13 is rotated by the Oldham ring 15 through the shaft 8 along with the rotation of the electric motor 2. By this series of operations, the refrigerant gas sucked from the suction pipe 17 is compressed and discharged from the discharge pipe 18 to the refrigeration cycle.

  FIG. 2 shows an enlarged view of the electric motor portion. FIG. 3 shows a cross-sectional view of the stator 2a. On the inner periphery of the hermetic container 1, there is provided an enlarged diameter portion 19 whose diameter is enlarged at the stepped portion 1c so that the stator 2a fits into the gap. At a plurality of locations on the outer peripheral side of the enlarged diameter portion 19, the stator 2 a and the sealed container 1 can be welded and fixed by the welded portion 20. Furthermore, the iron core of the stator 2a is not shown in detail, except for an auto-clamp method in which caulking work is simultaneously performed when the iron core is processed into a sheet metal. The strength may be improved by caulking or the like.

  In the drawing, for the sake of easy understanding, the gap 2f is expressed with a very large emphasis, but it is actually smaller. It is sufficient if the gap can be fitted to a certain extent. However, as a guideline, it is not required that the stator 2a be inserted into the sealed container 1 unless it is centered by a machine. It is enough if it is small enough to be inserted into the sealed container 1. The gap is basically the same in the following. The stator 2a is designed and manufactured in the same manner as in the past, such as press-fitting or shrink-fitting into the sealed container 1 before expanding the diameter.

  Welding is performed by leaving a hole of about 6 mm in the container and pouring the welding agent there. The portion of the welding agent shown in the figure is expressed like a screw or rivet in a cartoon style, and the portion corresponding to the screw or rivet foot expressed between the sealed container 1 and the stator 2a is: Actually, there is almost no foot length, but its diameter is about 6 mm, which is almost the same as the hole.

  The assembly procedure will be described.

  First, with respect to the cylindrical sealed container, a hole is formed in the welded portion of the stator 2a, and the sealed container 1 having an enlarged diameter corresponding to the outer peripheral portion of the stator 2a is manufactured. The stator 2a is inserted into the enlarged diameter portion 19 of the sealed container 1, and the outer peripheral portion is welded and fixed by a welding machine. At this time, it is preferable that the stator 2a is not welded while being in contact with the stepped portion 1c. This is because it is advantageous to avoid the occurrence of stress in the stator 2a due to the stepped portion 1c.

  Next, the shaft 8 on which the rotor 2b is press-fitted and fixed is prepared. A thin plate member for forming an air gap with the stator 2a is disposed on the outer peripheral portion of the rotor 2b, and is fixed in the stator 2a fixed to the hermetic container 1 in that state. Then, the structure of the part of the electric motor 2 is completed by removing the thin plate member installed in the outer peripheral part of the rotor 2b.

  Here, the stator 2a and the rotor 2b are displaced in the axial direction, and the rotor 2b is on the compression mechanism 3 side. This generates a magnetic force in the direction away from the compression mechanism 3 for the rotor 2b and suppresses the swing of the rotor 2b by pressing the shaft 8 connected to the rotor 2a against the fixed member 16. Is aimed at.

  FIG. 3 is a cross-sectional view perpendicular to the axis of the portion including the stator 2a. As described above, since the stator 2a is welded and fixed to the enlarged diameter portion 19 of the hermetic container with a gap fit, deformation of the stator core 2c and the core back 2h of the stator 2a can be suppressed. The core back 2h is not a portion on the outer diameter side of the tooth 2g but a portion on the outer diameter side of the space 2d set for the winding 2e, and welding is performed at this point. For this reason, the increase in the iron loss resulting from the stress which generate | occur | produces in an iron core can be prevented.

  In addition, although some stress is generated in the welded portion, it can be said that the stress is generated in a small portion when viewed from the whole stator 2a, so that the stress generated in the stator 2a can be made extremely small. It has become.

  Further, since the space 2d set for the winding 2e in the stator iron core 2c can be designed to the outer diameter side, the gap 2f on the iron core outer diameter side is almost eliminated. In the conventional configuration, since the stator 2a is fastened by press-fitting, shrink fitting, or the like, it can be said that a negative gap 2f is theoretically generated. According to the gap fitting as in the embodiment, it is possible to increase the volume of the stator iron core as much as possible while ensuring the gap 2f, that is, without causing stress on the stator 2a, and the stator iron core. The space set for the inner winding can be increased. As described above, since the area occupied by the winding 2e wound by the concentrated winding method can be made large, the motor efficiency can be improved.

  FIG. 10 shows the relationship between the reduction of the stress generated in the iron core and the improvement effect of the motor efficiency, which is derived from the measurement result of the shrinkage allowance of the stator 2a and the sealed container 1 and the motor efficiency.

  First, as a characteristic of the magnetic material, if stress is applied to the ferromagnetic material to change the outer shape, the magnetic moment will deviate from the easy magnetization direction even without an external magnetic field, and the iron loss will increase due to interaction with the magnetoelastic energy. There is a known phenomenon called the magnetostrictive inverse effect.

  Accordingly, the stator 2a and the sealed container 1 are shrink-fitted and fixed by applying a shrinkage stress to the iron core, and the stator 2a has a gap between the inner periphery of the sealed container 1 as shown in the first embodiment. In the specification in which the diameter-expanded portion 19 whose diameter is enlarged so as to be fitted is provided, and the specification with three welded portions of the stator 2a, the typical cooling operation conditions A, B, The motor efficiency was measured under the heating operation conditions A and B. The cooling operation condition A and the heating operation condition B mainly differ in the pressure ratio between the suction pressure and the discharge pressure and the operation rotational speed. In FIG. 10, the vertical axis indicates the motor efficiency, and the horizontal axis indicates the shrinkage allowance. The outer diameter of the stator used for the measurement was φ112 mm, and the shrinkage was about 100 μm and 150 μm. From the measurement results, it was confirmed that the motor efficiency was improved in the specification shown in the first example as compared with the case of shrink fitting regardless of the operating conditions. In addition, it was confirmed that the motor efficiency tends to be lower in the specifications with increased shrinkage allowance. From this result, it can be said that the structure of an Example leads to relaxation of the stress to the iron core by shrink fitting, and can improve motor efficiency with a reduction in iron loss.

  The second embodiment will be described with reference to FIG. The second embodiment is different from the first embodiment in the following points, and is basically the same as the first embodiment in other points. The stator iron core 2c, which is an iron core portion, is configured by crimping a large number of stacked stator iron plates. In FIG. 5, the position of the welded portion 20 for welding and fixing the stator 2a and the hermetic container 1 is set at the end of the stator iron core 2c on the compressor bottom side with respect to the axial direction of the stator 2a. There is an advantage that peeling at the caulking portion of the stator iron plate due to the weight of the child 2a can be prevented. In addition, the edge part which is the position of the welding part 20 is a position which is between about 10 mm from the lower end of the stator 2a, and the welding part 20 does not protrude from the stator 2a. Since the size of the welding point is about 6 mm as described above, it is preferable to leave a margin of about 10 mm.

  The third embodiment will be described with reference to FIG. The third embodiment is different from the first embodiment in the following points, and is basically the same as the first embodiment in other points. In FIG. 6, the position of the welded portion 20 for welding and fixing the stator 2a and the hermetic container 1 is set at the center of the stator iron core 2c with respect to the axial direction of the stator 2a. It is fixed by welding at the position, so it is highly stable. Further, there is an effect that fluctuation of the air gap 27 between the stator 2a and the rotor 2b due to vibration of the stator 2a during operation of the compressor can be reduced. The central part here means about ± 5 mm from the midpoint between one end and the other end when the stator 2a is viewed in the axial direction.

  The fourth embodiment will be described with reference to FIGS. The fourth embodiment is different from the first to third embodiments in the following points, and is basically the same as the first to third embodiments in other points.

  In FIG. 7, the stator 2 a is fixed at two welded portions 20 on the outer peripheral side of the enlarged diameter portion 19 through a gap between the stator 2 a and the enlarged diameter portion 19 of the sealed container 1. In order to obtain stable fixation, welding at three points is preferable, but two points may be considered from the viewpoint of process reduction. It is preferable because it is symmetrical in shape when viewed in cross section.

  In FIG. 8, the stator 2 a is fixed at three welded portions 20 on the outer peripheral side of the enlarged diameter portion 19 through a gap between the stator 2 a and the enlarged diameter portion 19 of the sealed container 1. As described above, stable fixing can be obtained with three points. Further, it is preferably a symmetrical shape when viewed in cross section. In the case of two points, it is extremely strong against vibration in one direction on the line connecting the welding points, but it cannot be said that it is extremely strong against vibration in a direction perpendicular thereto. On the other hand, the three-point symmetrical type is strong against vibrations in any direction. Not only from the point of shape, but also the three-point symmetry type is superior because of the relationship with the three-phase motor. This is because even if the welded portion causes stress on the iron core or affects the magnetic path, those effects are electrically symmetric. As a result, the vibration generated by the electric motor 2 is also canceled out, and only a small vibration is generated, so that the compressor becomes more reliable.

  In this way, by limiting the number of welded portions of the stator 2a to two or three, the deformation of the stator core 2c of the stator 2a is further suppressed as compared with the case where four or more locations are welded and fixed. Therefore, the motor efficiency can be improved by reducing the iron loss. Here, the welding location is set in consideration of the welding strength.

  The above embodiment is an example in which the stator 2a is welded to the enlarged diameter portion 19 of the hermetic container through a gap. However, even when the stator 2a is welded in an intermediate fitting state, the stator 2a is fixed by shrink fitting or press fitting. In contrast to this, the stress applied to the stator core can be reduced, and the performance improvement effect can be obtained.

  In particular, in the two-point welding that is the embodiment of FIG. 7, the intermediate fitting that can further reduce the gap 2f than the gap fitting reduces the inclination of the stator 2a with respect to the sealed container 1, and at this time, two points Fixing is supported by the sealed container 1 in addition to the welding points. Therefore, the configuration is more preferable from the viewpoint of stability and reliability. Furthermore, if this idea is pushed forward, ultimate one-point welding as shown in FIG. 9 may be used.

  Here, the intermediate fit is defined by JIS. “When fitting a hole and a shaft, which are finished within the allowable limit dimensions, respectively, a clearance may be formed depending on the actual dimension, or an interference may be formed. The tolerance zone of this overlaps the tolerance zone of the hole. "

  The refrigerant | coolant in the above Example is used for normal room air conditioners, such as R410A, and is HCFC refrigerant | coolant, HFC refrigerant | coolant, and HC refrigerant | coolant. In so-called Ecocute, carbon dioxide is used as a refrigerant for the compressor, and the refrigeration cycle becomes a supercritical refrigeration cycle and becomes very high pressure. Therefore, three or more points of welding are essential to ensure sufficient strength.

  The fifth embodiment is different from the first to fourth embodiments in the following points, and is basically the same as the first to fourth embodiments in other points. Considering that the above principle should be inherent during operation of the compressor rather than at the time of manufacture, that is, assuming that the explanation as explained above for the gap 2f can be obtained at the time of operation, It is also possible to adopt a configuration.

  Although not shown, a configuration like shrink fitting is considered in FIGS. The stator 2 a is fixed to the enlarged diameter portion 19 of the sealed container by press-fitting or shrink fitting, and is fixed by welding at one or two locations on the outer periphery of the stator 2 a and the enlarged diameter portion 19. According to this configuration, the fastening force can be increased as compared with the case where the stator 2a is fixed to the sealed container 1 only by press fitting or shrink fitting. In this configuration, when carbon dioxide that is a very high-pressure cycle as described above is used as a refrigerant, the sealed container 1 expands somewhat due to the high pressure. If the relationship between the bulge and the press-fitting or shrink-fitting is such that stress is not easily generated in the stator 2a by the sealed container 1, the effects described above can be obtained. For this reason, even in a high-pressure compressor using a carbon dioxide refrigerant, stress applied to the stator 2a and the stator core 2c can be reduced as compared with the case where the stator is fixed only by press-fitting or shrink fitting. Therefore, an increase in iron loss due to the stress of the iron core can be prevented.

  In addition, although the Example was described taking the vertical scroll compressor as an example as a typical example of a hermetic electric compressor, of course, this invention can be applied also to a horizontal type and the effect can be acquired. Further, the same applies to a rotary compressor and other hermetic electric compressors.

  As described above, the iron loss of the compressor is reduced by expanding the diameter of the sealed container corresponding to the axial length of the stator and welding and fixing the stator and the expanded diameter part of the sealed container. Can be made. As a result, an efficient compressor can be realized.

  By improving the compressor performance in this manner, the reduced amount of input can be sent to refrigeration cycle equipment such as an outdoor fan input, and the refrigeration capacity of the refrigeration cycle apparatus can be improved while maintaining the input.

DESCRIPTION OF SYMBOLS 1 Airtight container 2 Electric motor 2a Stator 2b Rotor 2c Stator iron core 2d Winding space 2e Winding 2f Gap 2g Teeth 2h Core back 3 Compression mechanism 12 Welding part 13 Turning scroll 14 Fixed scroll 15 Oldham ring 16 Fixing member 17 Suction pipe 18 Discharge pipe 19 Expanded portion 20 Welded portion

Claims (8)

In a hermetic type electric compressor having an electric motor composed of a stator and a rotor and a compression mechanism driven by the electric motor in a hermetic container,
The stator has a core back;
The sealed container has an enlarged diameter part whose diameter is enlarged at the step part,
The enlarged diameter portion is provided in a portion corresponding to the axial length of the stator,
The enlarged diameter portion and the core back are fixed by welding,
The stator is inserted into the sealed container by an intermediate fit ,
The position where the welding is performed is a central portion of the stator,
The hermetic electric compressor, wherein the stator does not contact the stepped portion . In a hermetic type electric compressor having an electric motor composed of a stator and a rotor and a compression mechanism driven by the electric motor in a hermetic container,
The stator has a core back;
The sealed container has an enlarged diameter part whose diameter is enlarged at the step part,
The enlarged diameter portion is provided in a portion corresponding to the axial length of the stator,
While having a gap between the enlarged diameter portion of the sealed container and the stator, the enlarged diameter portion and the core back are fixed by welding,
In the sealed container, the stator is inserted by an intermediate fit ,
The position where the welding is performed is a central portion of the stator,
The hermetic electric compressor, wherein the stator does not contact the stepped portion . In claim 1 or 2,
A hermetic electric compressor characterized in that there are two positions where the welding is performed. In claim 1 or 2,
A hermetic electric compressor characterized in that there are three positions where welding is performed. In claim 1 or 2,
The hermetic electric compressor is characterized in that the welding is performed at one position. In claim 1 or 2,
The position where the welding is performed is within 10 mm from the lower end of the stator.   In claim 1 or 2,
  The hermetic electric compressor is manufactured by enlarging a portion of the hermetic container corresponding to an outer peripheral part of the stator.   In claim 1 or 2,
  A hermetic electric compressor characterized in that a coil wound around the stator is wound by a concentrated winding method.

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