JP2011019398A - Stator, hermetically sealed compressor and rotating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly effective stator, capable of easing stress degradation in magnetic characteristics caused by compression stress generated, when the stator is shrinkage-fitted to a sealed case of a compressor, and capable of reducing iron loss, and to provide a hermetically sealed compressor and a rotating machine.SOLUTION: The stator has a cylindrical and stacked stator core to be fixed by shrinkage fitting, and the like, to the sealed case such as the hermetically sealed compressor. The stator core has: a plurality of slots disposed in a circumferential direction; magnetic pole teeth formed between the adjoining slots with a coil wound around; a plurality of regions divided in the circumferential direction by a radial central line of the magnetic pole teeth or the slots; and stress-ease holes formed in the predetermined number of regions, arranged at predetermined intervals in the circumferential direction of a plurality of regions, with a configuration elongated in the circumferential direction.

Description

  According to the present invention, a compression stress generated in the stator at the time of shrinkage fitting is provided on the outer periphery of the stator by providing a region in contact with the inner peripheral surface of the sealed container and a region in a non-contact manner at a predetermined interval in the circumferential direction. The present invention relates to a relaxed stator and a hermetic compressor.

  In order to provide a technique capable of reducing the reduction in efficiency of the rotating machine while adopting a structure in which the stator is held by the tightening force of the housing, the outer peripheral surface of the stator is in contact with the inner peripheral surface of the housing. There has been proposed a stator in which a non-contact surface that forms a gap is formed between the surface and the inner peripheral surface of the housing, and the center angle of the contact surface is set within a range of 130 degrees (for example, Patent Documents). 1).

JP 2006-191702 (page 7, FIG. 3) JP 2006-271105 A Japanese Patent Laid-Open No. 06-014482 JP 2001-008420 A

  When the stator is shrink-fitted into the compressor's sealed container, compressive stress is generated in the stator according to the tightening force, and the direction of the vector of the compressive stress and the direction of the magnetic flux vector generated in the stator are the same. In addition, the magnetic permeability of the electromagnetic steel sheet is lowered, resulting in iron loss deterioration. Conventional stators generate compressive stress almost uniformly in the core back where magnetic flux easily passes when the sealed container is fitted, and both the direction of the compressive stress vector and the direction of the magnetic flux vector are the same in the core back circumferential direction. Therefore, there are problems such as deterioration of magnetic properties of the electrical steel sheet and increase of iron loss.

  The present invention has been made to solve the above-described problems, and alleviates the stress deterioration of the magnetic characteristics caused by the compressive stress generated when the stator is shrink-fitted into the hermetic container of the compressor. It is an object of the present invention to provide a highly efficient stator, hermetic compressor, and rotating machine that can reduce the noise.

The stator according to the present invention is a stator having a cylindrical laminated stator core fixed to a hermetic container such as a hermetic compressor by shrinkage fitting,
The stator core
A plurality of slots arranged in a circumferential direction;
Magnetic pole teeth formed between adjacent slots and wound with a coil;
A plurality of regions divided in the circumferential direction by the radial center line of the magnetic teeth or slots;
A plurality of regions are provided in a predetermined number of regions arranged at regular intervals in the circumferential direction, and include stress relaxation holes formed long in the circumferential direction.

  The stator according to the present invention is capable of concentrating the compressive stress generated during shrink fitting at the contact end portion with the shell of the outer periphery of the stator that does not affect the magnetic path while maintaining symmetry of the stress distribution. This has the effect of alleviating the deterioration of the magnetic properties and reducing the iron loss.

FIG. 5 shows the first embodiment, and is a cross-sectional view of the vicinity of the electric element 50 in the hermetic compressor after shrink fitting. FIG. 5 shows the first embodiment and is a cross-sectional view of the vicinity of the electric element 50 in the hermetic compressor in which the deformation amount of the hermetic container 1 after shrink fitting is enlarged. The figure which shows Embodiment 1, The figure which shows the stress distribution of the stator core 3 after shrink fitting ((a) is the case where the outer periphery of the stator core 3 contacts the inner periphery of the airtight container 1, (b). Is the case of FIG. FIG. 5 shows the first embodiment and shows iron loss characteristics with respect to compressive stress of the electromagnetic steel sheet. FIG. 5 shows the first embodiment, and is a relationship diagram between a shrinkage allowance and an iron loss. FIG. 5 shows the first embodiment and is a cross-sectional view showing a first modification of FIG. 1. FIG. 5 is a diagram showing the first embodiment, and is a cross-sectional view showing a second modification of FIG. 1. FIG. 5 shows the second embodiment, and is a cross-sectional view of the vicinity of the electric element 50 in the hermetic compressor after shrink fitting. FIG. 5 shows the second embodiment, and is a cross-sectional view of the vicinity of the electric element 50 in the hermetic compressor after shrink fitting. FIG. 5 shows the third embodiment, and is a cross-sectional view of the vicinity of the electric element 50 in the hermetic compressor after shrink fitting. It is a figure which shows Embodiment 4, and is a cross-sectional view of the electric element 50 vicinity in the hermetic compressor after shrink fitting. FIG. 10 is a diagram showing the fifth embodiment, and is a plan view of divided stator cores 3a, 3b, 3c when the stator core 3 is divided and configured.

Embodiment 1 FIG.
1 to 7 are diagrams showing the first embodiment. FIG. 1 is a cross-sectional view of the vicinity of the electric element 50 in the hermetic compressor after shrink fitting, and FIG. 2 shows the deformation amount of the hermetic container 1 after shrink fitting. FIG. 3 is a cross-sectional view of the vicinity of the electric element 50 in the enlarged hermetic compressor, and FIG. 3 is a diagram showing the stress distribution of the stator core 3 after shrink fitting ((a) shows the outer periphery of the stator core 3 in the sealed container 1 (B) is the case of FIG. 1), FIG. 4 is a diagram showing the iron loss characteristic with respect to the compressive stress of the electromagnetic steel sheet, FIG. 5 is a relationship diagram between the shrinkage allowance and the iron loss, and FIG. 1 is a cross-sectional view showing a first modification of FIG. 1, and FIG. 7 is a cross-sectional view showing a second modification of FIG.

  In FIG. 1, the electric element 50 includes a stator 2 and a rotor 8. The stator 2 is fixed to the sealed container 1 (also called a housing) by shrink fitting. The sealed container 1 has a cylindrical shape with a thickness of about 3 mm, and is formed, for example, by drawing a steel plate. Although FIG. 1 shows an example of a hermetic compressor, a rotary machine may be used. In that case, the sealed container 1 is called a housing.

  The stator 2 includes a stator core 3 and a coil 6. The stator core 3 is configured by punching out thin electromagnetic steel sheets having a thickness of about 0.1 to 0.5 mm one by one and laminating a predetermined number. Before shrink fitting, it has a cylindrical shape whose outer diameter is slightly larger than the inner diameter of the sealed container 1. Further, the stator core 3 is subjected to an annealing process after the lamination of the electromagnetic steel sheets in order to relieve the distortion at the time of punching.

  The sealed container 1 is heated to about 200 ° C. by electromagnetic induction heating and is shrink-fitted to the stator 2 in an expanded state. The fitting allowance (shrinkage allowance) between the hermetic container 1 and the stator 2 is appropriately selected in the range of several tens to several hundreds μm according to the weight of the stator 2. By shrink fitting, the inner diameter of the sealed container 1 is set smaller than the outer diameter of the stator 2 at room temperature, and when the stator 2 is fitted to the sealed container 1, the sealed container 1 is heated and expanded, When the stator 2 is inserted with the inner diameter of the sealed container 1 larger than the outer diameter of the stator 2, and the stator 2 returns to room temperature, both are fixed. The fitting allowance (shrinkage allowance) refers to the difference between the outer diameter of the stator 2 and the inner diameter of the sealed container 1 at room temperature (the outer diameter of the stator 2> the inner diameter of the sealed container 1).

  The stator 2 of the present embodiment has nine slots 5. Magnetic pole teeth 4 are formed between adjacent slots 5. The magnetic pole teeth 4 have a substantially parallel shape from the outer diameter side to the inner diameter side. And it becomes the umbrella-shaped structure where both sides spread in the circumferential direction as it becomes a front-end | tip part (inner side).

  The coil 6 is, for example, a concentrated winding having a three-phase Y connection. The coil 6 has a predetermined number of turns of copper wire wound around the magnetic pole teeth 4 via an insulating member (not shown). The number of turns, the wire diameter, etc. of the coil 6 are determined according to the required rotation speed, torque, voltage specification, and the cross-sectional area of the slot 5. In the case of the present embodiment, for example, a copper wire having a wire diameter of about 0.5 mm is wound about 100 turns.

  On the other hand, the rotor 8 has a rotor shaft 7 that can be rotated by being fitted to a compression element (not shown) that compresses the refrigerant and is driven by the electric element 50, and the rotor shaft 7 is an axis of the stator 2. Arranged on the line. A perfect circular rotor 8 is fixed to the rotor shaft 7.

  A gap of about 0.3 to 1 mm is provided between the rotor 8 and the stator 2 so that the rotor 8 can rotate around the rotor shaft 7.

  The rotor 8 has a rotor core 9, and the rotor core 9 is configured by punching and stacking electromagnetic steel sheets one by one in the same manner as the stator core 3. The rotor core 9 is provided with a magnet accommodation hole 10 in the vicinity of the outer periphery. In the example of FIG. 1, six magnet housing holes 10 are formed in the circumferential direction.

  Six rare earth permanent magnets 35 are inserted into the six magnet housing holes 10 so that the north and south poles are alternately arranged. The rare earth permanent magnet 35 is mainly composed of neodymium, iron, and boron.

  Next, the shape of the outer peripheral portion of the stator core 3 that is a feature of the present embodiment will be described. The outer periphery of the stator core 3 includes a contact region 13 that contacts the sealed container 1 and a non-contact region 14 that does not contact the sealed container 1.

  The outer peripheral portion of the stator core 3 is divided into nine arc regions 12 by the center line 11 (radial direction) of nine magnetic pole teeth 4. Three arc regions 12 in the nine arc regions 12 are defined as non-contact regions 14. Three non-contact areas 14 are arranged at equal intervals (120 °). Two arc regions 12 between the non-contact regions 14 are defined as contact regions 13. Therefore, the ratio of the length in the circumferential direction between the contact area 13 and the non-contact area 14 is 2: 1.

  The non-contact area of the stator core 3 is set so that the outer peripheral radius of the non-contact area 14 not in contact with the inner peripheral surface of the sealed container 1 is smaller than the outer peripheral radius of the contact area 13 in contact with the inner peripheral surface of the closed container 1 by about 100 to 500 μm. An arc-shaped notch 15 is provided on the outer periphery of the contact region 14.

  FIG. 2 is a cross-sectional view of the vicinity of the electric element 50 showing an enlarged deformation amount when the closed container 1 shown in FIG. 1 is shrink-fitted. When the stator 2 configured as shown in FIG. 1 is shrink-fitted into the hermetic container 1, the hermetic container 1 is deformed using the contact end portions 16a, 16b, 16c, 16d, 16e, and 16f of the contact region 13 as fulcrums. At this time, since the non-contact regions 14 are provided at a constant interval (120 °) in the circumferential direction, the compressive stress 17 keeps the symmetry of the stress distribution and does not easily affect the magnetic path. The compressive stress of the core back inner peripheral portion 18 that concentrates on the contact end portions 16a, 16b, 16c, 16d, 16e, and 16f and is easy to pass the magnetic flux is relaxed.

  3A and 3B are diagrams showing the stress distribution of the stator core 3 after shrink fitting. FIG. 3A is a case in which the outer periphery of the stator core 3 is in full contact with the inner periphery of the hermetic container 1, and FIG. It is. The magnitude of the compressive stress is expressed by shading. The darker the color, the greater the compressive stress. In the case of FIG. 1 in (b), as described above, the compressive stress 17 does not affect the magnetic path while maintaining the symmetry of the stress distribution as compared with the case of full contact in (a). The compressive stress of the core back inner peripheral portion 18 (see FIG. 2) that concentrates on the contact end portions 16a, 16b, 16c, 16d, 16e, and 16f with the container 1 and easily passes the magnetic flux is alleviated.

  FIG. 4 shows iron loss characteristics with respect to compressive stress in the electromagnetic steel sheet of the stator core 3. The iron loss of electrical steel sheets has a characteristic that it becomes saturated when the compressive stress increases. The iron loss locally concentrates the compressive stress on the contact end portions 16a, 16b, 16c, 16d, 16e, and 16f, and relieves the stress in the core back inner peripheral portion 18 where the magnetic flux easily passes. The rate of loss deterioration can be reduced. Moreover, since it is configured to maintain the symmetry of the stress distribution, magnetic distortion can be suppressed.

  Further, in the stator 2 configured as described above, the compressive stress is concentrated on the contact end portions 16a, 16b, 16c, 16d, 16e, and 16f of the contact region 13. Therefore, the direction of the compressive stress vector is inclined in the direction of the contact end portions 16a, 16b, 16c, 16d, 16e, and 16f, and the non-parallel component with the direction of the magnetic flux vector generated in the circumferential direction is increased. Since the increase in the iron loss is caused only by the component in the same direction as the magnetic flux vector of the compressive stress, the magnetic characteristic deterioration of the magnetic steel sheet is alleviated and the stress is concentrated on the contact end portions 16a, 16b, 16c, 16d, 16e, and 16f. Together with the effect, the iron loss can be reduced as shown in FIG.

  In FIG. 1, the ratio of the lengths in the circumferential direction between the contact area 13 and the non-contact area 14 is 2: 1. However, as shown in FIG. 6, the contact area in contact with the inner peripheral surface of the sealed container 1. The same effect can be obtained even when the ratio of the lengths in the circumferential direction between the non-contact region 14 that does not contact the inner peripheral surface of the airtight container 1 is 1: 2.

  The stator 2 according to the present embodiment is configured by nine slots 5, but a plurality of arc regions 12 divided by the center line 11 (radial direction) of the magnetic teeth 4 are formed regardless of the number of slots. The same effect can be obtained by dividing the contact region 13 in contact with the inner peripheral surface of the sealed container 1 and the non-contact region 14 not in contact with the inner peripheral surface of the sealed container 1 and arranging them at regular intervals.

  Further, as shown in FIG. 7, even when a groove 30 for holding the stator 2 and a vent hole 31 for passing a refrigerant are provided on the outer peripheral portion of the stator 2, it does not depend on the number of slots. A plurality of arc regions 12 divided by the center line 11 (radial direction) of the magnetic teeth 4 are contact regions 13 that are in contact with the inner peripheral surface of the sealed container 1 and non-contact regions 14 that are not in contact with the inner peripheral surface of the sealed container 1. The same effect can be obtained by dividing each of the above and arranging them at regular intervals.

  Since the stress deterioration of the iron loss is greater as the magnetic flux density is higher, the iron loss reduction effect is higher as the magnetic flux density of the stator core 3 is higher. The coil 6 is a concentrated winding with a high winding density, and is an electric motor using a rare earth magnet 35 having a high magnetic force for the rotor 8 and has a particularly great effect.

  The compressive stress generated in the stator 2 increases as the fitting allowance (shrinkage allowance) between the stator 2 and the sealed container 1 increases. Since the stress relaxation effect of the present embodiment is larger as the compressive stress is larger, a significant improvement in iron loss deterioration can be expected when the fitting allowance (shrinkage allowance) is larger than 100 μm.

  The stator core 3 in the present embodiment is subjected to an annealing process for alleviating punching distortion. When shrink fitting is performed without annealing, the electrical steel sheet is harder than that annealed and generates a larger compressive stress. Therefore, the stress relaxation effect of the present embodiment is even higher, and the iron loss is greatly reduced. Improvement can be expected.

  Further, the stator 2 is provided with non-contact areas 14 that do not contact the inner peripheral surface of the sealed container 1 at regular intervals in the circumferential direction, thereby making it difficult for vibration and noise generated in the stator 2 to be transmitted to the sealed container 1. It not only suppresses stress deterioration due to iron loss, but is also effective in reducing vibration and noise.

  In the present embodiment, the effect in the case of shrink fitting has been described, but it is clear that compressive stress is generated even when the stator 2 is fixed to the closed container 1 by a method such as cold fitting or press fitting. Embodiments can be applied.

  This embodiment is effective for increasing the efficiency of the motor under a condition in which the iron loss ratio is higher than the copper loss, and a significant improvement effect can be expected with a high-speed motor having a high iron loss ratio.

  The electric motor of the present embodiment is a brushless DC motor, but the same effect can be obtained even if the electric motor does not use a permanent magnet such as an induction motor regardless of the type of magnet.

Embodiment 2. FIG.
8 and 9 show the second embodiment, and are cross-sectional views of the vicinity of the electric element 50 in the hermetic compressor after shrink fitting.

  In the first embodiment shown in FIGS. 1 and 6, a plurality of arc regions 12 divided by the center line 11 (radial direction) of the magnetic teeth 4 are contacted with the inner peripheral surface of the sealed container 1, The airtight container 1 is divided into non-contact areas 14 that do not come into contact with the inner peripheral surface, and each is arranged at regular intervals. On the other hand, in the present embodiment, as shown in FIGS. 8 and 9, the plurality of arc regions 19 divided by the center line 27 (radial direction) of the slot 5 are in contact with the inner peripheral surface of the sealed container 1. The same effect can be obtained by dividing the region 20 and the non-contact region 21 that is not in contact with the inner peripheral surface of the sealed container 1 and arranging them at regular intervals.

  In the example of FIG. 8, the ratio of the length in the circumferential direction between the contact area 20 and the non-contact area 21 is 2: 1.

  In the example of FIG. 9, the ratio of the length in the circumferential direction between the contact area 20 and the non-contact area 21 is 1: 2.

Embodiment 3 FIG.
FIG. 10 shows the third embodiment, and is a cross-sectional view of the vicinity of the electric element 50 in the hermetic compressor after shrink fitting.

  In the first embodiment shown in FIGS. 1 and 6, a plurality of arc regions 12 divided by the center line 11 (radial direction) of the magnetic teeth 4 are contacted with the inner peripheral surface of the sealed container 1, The airtight container 1 is divided into non-contact areas 14 that do not come into contact with the inner peripheral surface, and each is arranged at regular intervals. On the other hand, in this embodiment, as shown in FIG. 10, a plurality of arc regions 12 divided by the center line 11 (radial direction) of the magnetic teeth 4 are formed with notched holes 22 ( The same effect can be obtained even when the region 23 provided with an example of the stress relaxation hole and the region 24 not provided with the notch hole 22 are provided at regular intervals in the circumferential direction. From the viewpoint of preventing magnetic saturation of the core back, it is desirable that the notch hole 22 is disposed at a position close to the outer periphery of the core back within an allowable range of strength. The arc region 12 may be divided by the center line 27 (radial direction) of the slot 5.

Embodiment 4 FIG.
FIG. 11 shows the fourth embodiment, and is a cross-sectional view of the vicinity of the electric element 50 in the hermetic compressor after shrink fitting.

  In the first embodiment shown in FIGS. 1 and 6, a plurality of arc regions 12 divided by the center line 11 (radial direction) of the magnetic teeth 4 are contacted with the inner peripheral surface of the sealed container 1, The airtight container 1 is divided into non-contact areas 14 that do not come into contact with the inner peripheral surface, and each is arranged at regular intervals. On the other hand, in the present embodiment, in addition to this, both ends in the circumferential direction of the contact region 13 have a whisker structure as shown in FIG. The whiskers 25 serve as springs that absorb the tightening forces at both ends in the circumferential direction of the contact region 13.

  By configuring as described above, stress at both ends in the circumferential direction of the contact region 13 generated when shrink-fitting can be released to the whisker 25, and further, the contact area with the sealed container 1 is increased. The holding force of the stator 2 can be enhanced.

Embodiment 5 FIG.
FIG. 12 shows the fifth embodiment, and is a plan view of the divided stator cores 3a, 3b, 3c when the stator core 3 is divided and configured.

  In the first embodiment shown in FIGS. 1 and 6, a plurality of arc regions 12 divided by the center line 11 (radial direction) of the magnetic teeth 4 are contacted with the inner peripheral surface of the sealed container 1, The airtight container 1 is divided into non-contact areas 14 that do not come into contact with the inner peripheral surface, and each is arranged at regular intervals. In contrast, in the present embodiment, in addition to this, the stator 2 is divided into a plurality of parts in the axial direction, and the axially divided core is rotated and laminated in the circumferential direction. The rotation angle is a multiple of the circumferential interval (pitch) of the magnetic teeth 4. In the example of FIG. 12, there are nine magnetic pole teeth 4, and the circumferential interval between the magnetic pole teeth 4 is 40 degrees. Accordingly, the second stage in FIG. 12B is rotated by 40 degrees. Further, the third stage in FIG. 12C is rotated by 80 degrees.

  By configuring as described above, stress at the contact end portion between the sealed container 1 and the stator core 3 (for example, the contact end portions 16a, 16b, 16c, and the like in the contact region 13 in FIG. 16d, 16e, and 16f) can be evenly distributed in the U, V, and W phases, and magnetic symmetry is improved. Moreover, since the contact area | region 13 with the airtight container 1 is uniformly disperse | distributed to the circumferential direction, a contact force improves and a detachment | loading load can be strengthened. It should be noted that this embodiment can also be applied to the stator 2 shown in FIG. 9 of the third embodiment.

Embodiment 6 FIG.
In the above embodiment, the stator 2 has an integral core shape. However, even if the stator 2 is configured by combining split cores, the stator 2 has the magnetic pole teeth 4 having the same outer diameter. A contact region 13 having a large diameter that comes into contact with the inner peripheral surface of the sealed container 1 and a non-contact region 14 having a small diameter that are not in contact with each other are formed of two types of split cores of magnetic teeth 4 having different outer diameters. The same effect can be obtained by configuring at a regular interval in the circumferential direction. In addition, this Embodiment is applicable also to the stator 2 shown in FIG. 10 of Embodiment 3. FIG.

1 sealed container, 2 stator, 3 stator core, 4 magnetic teeth, 5 slots, 6
Coil, 7 Rotor shaft, 8 Rotor, 9 Rotor core, 10 Magnet receiving hole, 11 Center line of magnetic teeth 4, 12 Arc region, 13 Contact region, 14 Non-contact region, 15 Notch, 16a Contact end 16b contact end, 16c contact end, 16d contact end, 16e
Contact end, 16f Contact end, 17 Compressive stress, 18 Core back inner periphery, 19 Arc region, 20 Contact region, 21 Non-contact region, 22 Notched hole, 27 Center line of slot 5,
30 grooves, 31 ventilation holes, 50 electric elements.

Claims (7)

In a stator having a cylindrical laminated stator core fixed to a hermetic container such as a hermetic compressor by shrink fitting,
The stator core is
A plurality of slots arranged in a circumferential direction;
Magnetic pole teeth formed between adjacent slots and wound with a coil;
A plurality of regions divided in the circumferential direction by a radial center line of the magnetic pole teeth or the slots;
A stator comprising: a stress relaxation hole provided in a predetermined number of regions arranged at regular intervals in the circumferential direction in the plurality of regions and formed long in the circumferential direction.   2. The stator according to claim 1, wherein the stator core is divided into a plurality of parts in the axial direction, and the cores divided in the axial direction are stacked at a predetermined angle in the circumferential direction.   2. The stator according to claim 1, wherein the stator core portion in the region having the stress relaxation hole and the stator core portion in another region are divided. 3.   The stator according to any one of claims 1 to 3, wherein annealing is not performed after the lamination.   The airtight container includes a compression element for compressing the refrigerant and an electric element for driving the compression element. The stator according to any one of claims 1 to 4 is used for the electric element. Hermetic compressor.   5. A permanent magnet type motor comprising a stator, a rotor, and a housing, wherein the stator is held by a tightening force of the housing, and the permanent magnet type motor according to claim 1. A rotating machine characterized by using a stator.   5. A permanent magnet type motor comprising a concentrated magnetic coil in a magnetic pole tooth of a stator and a permanent magnet of a rotor made of a rare earth magnet, wherein the permanent magnet type motor is fixed to any one of claims 1 to 4. A rotating machine characterized by using a child.

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