JP2014166095A - Stator, sealed compressor and motor equipped with the same, and mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator capable of relaxing a fastening force acting on a stator core and thereby suppressing core loss increase caused by compression stress of the stator core.SOLUTION: The stator includes stator cores 5 each of which is configured by laminating a doughnut-shaped core formed by disposing magnetic pole teeth 7 in a circumferential direction, wherein the magnetic pole teeth 7 have a plurality of fixed pieces fixed to a housing at an outer peripheral part in a circumferential direction, in a lamination direction, two or more kinds of magnetic pole teeth 7a, 7b mutually different in positions of fixed pieces are laminated.

Description

  The present invention molds, for example, a stator that is fixed to a hermetic container or a housing such as a frame by shrink fitting, press fitting, and the like, a hermetic compressor and a rotary machine including the stator, and a stator iron core of the stator. It relates to molds.

  There has been proposed a technique for reducing a reduction in the efficiency of a rotating machine while adopting a structure in which a stator core of a stator is held by a tightening force of an airtight container. The stator core is configured by alternately laminating a plurality of electromagnetic steel plates (cores) having different outer diameters (see, for example, Patent Document 1).

JP 2008-220112 A (page 5, FIG. 1)

When the stator core is fixed to the hermetic container by shrink fitting, press fitting, or the like, a compressive stress corresponding to the tightening force (force generated by shrinkage of the hermetic container at the time of shrink fitting) is generated inside the stator core. Due to this compressive stress, the magnetic permeability of the magnetic steel sheet constituting the stator core decreases, and the iron loss increases. The stator core described in Patent Document 1 described above relaxes the tightening force acting on the stator core by alternately laminating a plurality of cores having different outer diameters.
However, in order to stack a plurality of cores having different outer diameters, it is necessary to stack them after discharging the products from a plurality of molds punched with different outer diameters. There existed a subject that the manufacturing cost of stators, such as expense, increased. Furthermore, there has been a problem that a slight positional deviation occurs when the cores are combined and laminated by combining the cores in a subsequent process. In addition, it is extremely difficult to make the inner diameter roundness and shape of the core punched by different molds the same, and the inner diameter roundness and shape imbalance of the core cause noise and vibration. There was a problem.

The present invention has been made in order to solve the above-described problems, and a first object is to alleviate the tightening force acting on the stator core, and accordingly, is caused by the compressive stress of the stator core. An object of the present invention is to obtain a stator capable of suppressing an increase in iron loss and further suppressing vibration and noise generated in the stator, a hermetic compressor and a rotary machine including the stator, and a mold.
A second object is to obtain a stator capable of improving the inner diameter roundness of the core without increasing the manufacturing cost of the stator, a hermetic compressor and a rotary machine including the stator, and a mold. The purpose is to be able to.

  A stator according to the present invention includes a stator iron core formed by stacking doughnut-shaped cores having the same outer diameter formed by arranging magnetic pole teeth in the circumferential direction, and the magnetic pole teeth have an outer circumference in the circumferential direction. A plurality of fixed pieces fixed to the housing are provided in the portion, and two or more types of magnetic pole teeth having different positions of the fixed pieces are stacked in the stacking direction.

  According to the present invention, the magnetic pole teeth have a plurality of fixed pieces fixed to the housing on the outer peripheral portion in the circumferential direction, and two or more types of magnetic pole teeth having different positions of the fixed pieces are stacked in the stacking direction. ing. With this configuration, the contact area with the housing per core layer can be reduced. For this reason, the force holding the stator core of the housing is reduced, the compressive stress generated inside the stator core can be relaxed, and the increase in iron loss due to the compressive stress of the stator core can be suppressed. Moreover, the vibration and noise which generate | occur | produce in a stator can be suppressed by reducing the clamping force of a housing.

The cross-sectional view which shows schematic structure of the electrically-driven element of the hermetic compressor which concerns on embodiment. The longitudinal cross-sectional view of the electrically-driven element shown in FIG. The top view which shows the magnetic pole teeth of the stator core shown in FIG. The longitudinal cross-sectional view of the electrically-driven element which shows the modification of FIG. The top view which shows the lamination example of the 1st core and the 2nd core which were punched out by the metal mold | die in embodiment to donut shape. The top view which shows the magnetic pole teeth shape | molded and arrange | positioned with the metal mold | die different from FIG. The top view which arrange | positions and shows the magnetic pole teeth shape | molded by the metal mold | die different from FIG. 5 in circular arc shape. The longitudinal cross-sectional view which shows the electric element of the conventional hermetic compressor. The cross-sectional view which shows the stator core of the electric element of FIG. 8 as viewed from above. The top view which shows the magnetic pole teeth of the stator core of FIG.

  1 is a transverse sectional view showing a schematic configuration of an electric element of a hermetic compressor according to an embodiment, FIG. 2 is a longitudinal sectional view of the electric element shown in FIG. 1, and FIG. 3 is a magnetic pole of the stator core shown in FIG. FIG. 4 is a longitudinal sectional view of an electric element showing a modification of FIG. 2.

  The hermetic compressor according to the present embodiment includes a compression element (not shown) incorporated in the hermetic container 4 and the electric element 1. The electric element 1 includes, for example, a brushless DC motor (permanent magnet type motor) including a stator 2 and a rotor 3 that is rotated by a rotating magnetic field generated in the stator 2 as illustrated in FIGS. Drives a compression element that compresses the refrigerant.

  The stator 2 includes a stator core 5 and a coil 8 formed in a substantially cylindrical shape, and is fixed to the sealed container 4 by, for example, shrink fitting. Here, shrink fitting will be described. The outer diameter of the stator 2 is set larger than the inner diameter of the hermetic container 4 at room temperature, and the hermetic container 4 is heated to a high temperature (for example, 200 ° C.) to expand, so that the hermetic container is larger than the outer diameter of the stator 2 at room temperature. 4. Increase the inner diameter of 4. And if the stator 2 of normal temperature is inserted in the hot airtight container 4 and the temperature of the airtight container 4 is lowered, the airtight container 4 contracts and the stator 2 is fastened and fixed from the radial direction. This is called shrink fitting. In the stator 2 after shrink fitting, a compressive stress is generated by the tightening force of the hermetic container 4. In this embodiment, the compressive stress is reduced. A specific example of this point will be described later.

  The rotor 3 includes, for example, six rare earth elements in which a rotor shaft 13 fitted in a hole provided in a central portion and N poles and S poles are alternately provided in the circumferential direction in the vicinity of the outer periphery of the rotor 3. And a permanent magnet 11. The rotor 3 is disposed with a gap 12 of about 0.3 to 1 mm between the rotor 2 and is rotatable about the rotor shaft 13. The rare earth permanent magnet 11 is formed of six magnetized flat plate-shaped neodymium, iron, and boron having a substantially regular hexagonal shape, and six magnet insertion holes provided near the outer periphery of the rotor 3. 10 is inserted.

  The sealed container 4 is formed by drawing a steel plate having a thickness of about 3 mm. Moreover, when the thickness of a steel plate is about 6 mm, the steel plate is shape | molded by a bending process, the joining surface is couple | bonded by welding, and the airtight container 4 is comprised.

  The above-described stator core 5 is formed by alternately laminating a predetermined number of first cores 5a and second cores 5b formed by punching a magnetic steel sheet having a thickness of about 0.1 to 0.7 mm into a predetermined shape. (See FIG. 2). The outer diameter of the stator core 5 is slightly larger than the outer diameter of the sealed container 4. The difference between the outer diameter of the stator core 5 and the inner diameter of the sealed container 4 at room temperature is referred to as shrinkage allowance. The shrinkage allowance varies depending on the weight of the stator 2 (when the weight of the stator 2 is increased, the shrinkage allowance is increased), but is approximately several tens to several hundreds of μm. The stator core 5 is subjected to an annealing process after the first core 5a and the second core 5b are laminated in order to alleviate distortion at the time of punching. Note that the annealing treatment may not be performed depending on the type of the electromagnetic steel sheet that is the material of the first core 5a and the second core 5b.

  On the first core 5a and the second core 5b of the stator core 5, nine magnetic pole teeth 7 (7a, 7b) are formed at substantially equal intervals in the circumferential direction by punching out electromagnetic steel sheets. The magnetic pole teeth 7a are provided on the first core 5a, and the magnetic pole teeth 7b are provided on the second core 5b. Slots 6 (spaces) are formed radially between the magnetic teeth 7a and 7b. The magnetic teeth 7a and 7b have substantially the same circumferential width from the outer diameter side to the inner diameter side. In addition, the tip portions on the inner diameter side of the magnetic pole teeth 7a and 7b have an umbrella shape spreading on both sides in the circumferential direction. Each of the magnetic teeth 7a and 7b is automatically connected and stacked in the mold by eight magnetic tooth connecting projections 16 and fastening caulking portions 15 for stacking the cores. In this case, the 1st core 5a and the 2nd core 5b are laminated | stacked alternately, and the stator core 5 comprised by the lamination | stacking is discharged | emitted from a metal mold | die.

  Each of the magnetic teeth 7 is wound with the coil 8 described above. The coil 8 is formed by winding a magnet wire directly around the magnetic pole teeth 7 via an insulator. This winding method is called concentrated winding. This coil 8 is connected in a three-phase Y connection and generates a rotating magnetic field that gives rotation to the rotor 3. The number of turns and the wire diameter of the coil 8 are determined according to required characteristics (rotation speed, torque, etc.), voltage specifications, and the cross-sectional area of the slot 6. In the present embodiment, for example, a magnet wire having a wire diameter of about 0.5 mm is wound around each magnetic pole tooth 7 for about 100 turns.

Here, the outer peripheral shape of the first core 5a and the second core 5b of the stator iron core will be described. Before that, the outer peripheral shape of the core constituting the conventional stator iron core will be described with reference to FIGS. To do.
8 is a longitudinal sectional view showing an electric element of a conventional hermetic compressor, FIG. 9 is a transverse sectional view showing the stator core of the electric element of FIG. 8 as viewed from above, and FIG. 10 is an illustration of the stator core of FIG. It is a top view which shows magnetic pole teeth.

  The stator 2 of the electric element 1 in FIGS. 8 and 9 includes a stator core 5 configured by laminating a predetermined number of cores 5c formed by punching electromagnetic steel sheets into a predetermined shape. As shown in FIG. 10, four convex fixing pieces 9e, 9f, 9g, and 9h (portions excluding the cutouts 14) formed by punching are provided on the outer peripheral portion 9 of each magnetic pole tooth 7 of each core 5c. Are provided. That is, the core 5c has the same shape having the fixing pieces 9e, 9f, 9g, and 9h for each magnetic pole tooth 7 (same phase). When the cores 5c having the same shape are stacked, as shown in FIGS. 8 and 9, the fixing pieces 9e, 9f, 9g, and 9h are stacked in the stacking direction for each same phase.

Next, the outer peripheral shape of the 1st core 5a and the 2nd core 5b in this Embodiment is demonstrated using FIGS. 1-3.
As shown in FIG. 3 (a), two convex fixing pieces 9b and 9c (portions excluding the cutout 14) formed by punching are provided on the outer peripheral portion 9 of each magnetic pole tooth 7a of the first core 5a. Is provided. Further, as shown in FIG. 3B, the outer peripheral portion 9 of each magnetic pole tooth 7b of the second core 5b has two convex fixed pieces 9a and 9d (notches 14 removed) formed by punching. Part) is provided. The fixing pieces 9a, 9d of the magnetic pole teeth 7b are provided at positions farther in the circumferential direction than the fixing pieces 9b, 9c of the magnetic pole teeth 7a. The outer peripheral shapes of the first core 5a and the second core 5b are different from each other.

  When the first and second cores 5a and 5b having different outer peripheral shapes are alternately stacked and the stator core 5 is fixed to the closed container 4 by shrink fitting (see FIG. 2), as shown in FIG. 7 (same phase), the fixed pieces 9a, 9b, 9c, 9d are arranged in the circumferential direction, and the fixed pieces 9b, 9c and 9a, 9d are alternately stacked in the stacking direction.

  As described above, in the present embodiment, the protruding pieces 9b and 9c provided on the outer peripheral portion 9 of each magnetic pole tooth 7a of the first core 5a and the outer peripheral portion 9 of each magnetic pole tooth 7b of the second core 5b are provided. By laminating the projecting pieces 9a and 9d thus formed in the same phase, a surface that is in contact with or not in contact with the hermetic container 4 in the laminating direction is formed on the outer peripheral surface of the stator core 5. Thereby, the contact area with the airtight container 4 of the outer peripheral surface of the stator core 5 can be made small compared with the stator core 5 shown in FIG.

  By reducing the contact area between the outer peripheral surface of the stator core 5 and the hermetic container 4, the force for holding the stator core 5 of the hermetic container 4 when the stator core 5 is fixed to the hermetic container 4 is reduced. The Therefore, for example, the force for tightening the stator core 5 of the sealed container 4 can be reduced, and the compressive stress generated in the stator core 5 can be reduced. Thereby, the iron loss increase resulting from the compressive stress of the stator core 5 can be suppressed.

  The stress deterioration of iron loss is greater as the magnetic flux density is higher. As shown in FIG. 1, in the electric element 1 in which the coil 8 is a concentrated winding having a high winding density and the rare earth permanent magnet 11 is used for the rotor 3, the magnetic flux density is high. The effect of suppressing the stress deterioration of iron loss by reducing the force of tightening the stator core 5 of the sealed container 4 while reducing the contact area with the sealed container 4 at the time of fitting and maintaining the holding force becomes particularly large.

  In addition, the stator core 5 is less effective in reducing vibration and noise by reducing the tightening force due to shrink fitting of the sealed container 4 so that vibration and noise generated in the stator 2 are not easily transmitted to the sealed container 4. is there.

In the present embodiment, the first core 5a and the second core 5b are alternately stacked, but instead of this, a core constituted by the magnetic pole teeth 7c shown in FIG. You may laminate | stack alternately the core comprised by the magnetic pole teeth 7d shown to 3 (d).
Moreover, although the 1st core 5a and the 2nd core 5b are laminated | stacked alternately, it is not limited to this, For example, as shown in FIG. 4, one 1st core 5a and 2nd core 5b are shown. May be stacked in the order of three sheets.
In addition, as shown in FIG. 3, four types of cores each composed of the magnetic pole teeth 7a, 7b, 7c, and 7d may be alternately and repeatedly stacked.

Next, production equipment and molds for manufacturing the stator core 5 will be briefly described.
Generally, when manufacturing a stator core, a high-speed press is used, and a punching speed of about 150 to 400 spm depending on conditions such as a mold structure, a material width to be used, and a material feed length per stroke. A punching process is performed. There are two types of molds: a method in which a rotor core and a stator core are simultaneously punched, and a method in which each is punched with separate dies.

  The die used for manufacturing the stator core 5 generally adopts a progressive feeding method (sequential feeding die). While feeding the electromagnetic steel sheets in order from the starting step, the magnetic pole teeth portion 7, The inner diameter portion, the fastening caulking portion 15 for lamination, the protrusion 16 for connecting the teeth, and the like are punched out, and a predetermined product shape (a donut-shaped core) is formed and laminated automatically in the final process. In the present embodiment, the first and second cores 5a and 5b are alternately stacked. Further, the mold has a structure in which it is separated into a predetermined core height while being automatically laminated.

  Here, the punching method of the progressive metal mold | die in this Embodiment is demonstrated. FIG. 5 shows a shape when the teeth connecting core is punched in the final punching process of the stator core 5 in the mold, and the stack is automatically laminated in the shape of a donut shape as shown in the figure. The progressive die in the present embodiment has a plurality of blades for molding the fixing pieces 9b, 9c on the outer peripheral portion 9 of the first core 5a and the fixing pieces 9a, 9d on the outer peripheral portion 9 of the second core 5b. And a plurality of punching steps (fixed piece molding step), and these steps arranged before the final step have an intermittent control mechanism that enables / disables punching of each step according to an arbitrary setting.

  By applying this intermittent control mechanism to the punching process, it is possible to automatically stack any combination of cores having magnetic teeth 7a, 7b (or 7c, 7d) as shown in FIG. 4 in the final process. . In the present embodiment, four core shapes are shown as an example. However, if the length of the outer peripheral portion 9 per laminated core is substantially the same, even if the core shape is arbitrarily changed, after shrink fitting A similar effect can be obtained by relieving the compressive stress generated in the stator core 5.

  In addition, in the manufacture of the stator core 5, if the shape (outer diameter) of the fixed piece is changed in the entire lamination direction in order to relieve the compressive stress generated inside the stator core 5 after shrink fitting, the compressive stress Is unbalanced, the roundness of the inner diameter of the stator core 5 after shrink fitting is deteriorated, which causes noise and vibration. Therefore, the automatically laminated stator core 5 in the present embodiment has the same core outer diameter, the fixing with the sealed container 4 per core layer is substantially the same, and the core having a different outer peripheral shape is arbitrarily changed. Therefore, when the laminated core is viewed as a whole while reducing the contact area with the sealed container 4 per layer, the same shrink fitting as the stator core 5 shown in FIGS. Can be avoided. Therefore, the inner diameter roundness of the stator core 5 after shrink fitting can be maintained equal to the stator core 5 shown in FIGS. 8 and 9, and noise and vibration deterioration can be suppressed.

  Further, in order to improve the deterioration of the roundness of the inner diameter of the stator core 5, there is a method that can be solved by correcting the size of the blade that punches out the inner diameter. In this embodiment, FIG. 8 and FIG. Since the inner diameter roundness equivalent to the stator core 5 shown in the figure can be maintained, it is not necessary to manufacture a new blade, and the manufacturing cost of an expensive blade can be suppressed.

  Therefore, by using the stator core 5 of the present embodiment, the force with which the hermetically sealed container 4 tightens the stator core 5 can be reduced, the compressive stress generated inside the stator core 5 is relieved, and the iron due to the compressive stress is reduced. Loss deterioration can be reduced, and the production of the stress-relieving stator core 5 can be realized.

  Moreover, as shown in the above-mentioned Patent Document 1, in order to stack a plurality of cores having different outer diameters, it is necessary to combine and stack the products after discharging the products from a plurality of molds punched with different outer diameters. . For this reason, the manufacturing cost of the stator, such as the manufacturing cost of the mold, the assembly equipment, and the operating cost, is increased, and further, a slight misalignment occurs when the cores are combined and laminated by combining different cores in the subsequent process. Also, it is extremely difficult to make the inner diameter roundness and shape of each core punched with different molds the same, and the inner diameter roundness and shape imbalance of each core is a cause of noise and vibration. It becomes.

  Therefore, in the present embodiment, a combination lamination of the first and second cores 5a and 5b having irregularly shaped fixing pieces 9a to 9d molded on the outer peripheral portion 9 with one progressive die can be arbitrarily performed. Furthermore, since the first and second cores 5a and 5b are automatically stacked in the same progressive die, no positional deviation occurs and the roundness and shape of the inner diameter of the first and second cores 5a and 5b are stable. Therefore, it is possible to manufacture the stator core 5 that can be laminated with high accuracy and can relieve stress while suppressing the manufacturing cost.

  In the present embodiment, the example in which the stator core 5 is fixed to the hermetic container 4 by shrink fitting has been described. However, by other methods such as cold fitting (method for cooling the stator 2) or press fitting. The stator core 5 may be fixed to the sealed container 4.

  In the present embodiment, the brushless DC motor has been described as an example of the electric element 1 of the hermetic compressor. However, the present invention is also applicable to a rotating machine that does not use a permanent magnet such as an induction motor other than the hermetic compressor. The same effect as this embodiment can be obtained.

  The progressive mold used for manufacturing the stator core 5 has been described with the stator core 5 having a teeth-connected core. However, the present invention is not limited to this, and the core of the rotor 3 and the stator core 5 can be simultaneously used. It can also be applied to molds that can be punched.

  In addition, in a mold for punching only the stator core, in addition to a general donut punching method as shown in FIG. 5, a method in which magnetic teeth 7 are arranged in a straight line as shown in FIG. The present invention is also applicable to a mold that employs a system in which an arbitrary number of magnetic teeth 7 are arranged in an arc shape as shown in FIG.

  Further, in the present embodiment, the stator core 5 has been described as having a teeth connecting core. However, the stator core 5 is configured by a tooth split core having no teeth connecting projections 16 or an integral core. Even if it is a thing, if the lamination | stacking method of an electromagnetic steel plate is the same, the same effect can be acquired.

  DESCRIPTION OF SYMBOLS 1 Electric element, 2 Stator, 3 Rotor, 4 Sealed container, 5 Stator core, 5a 1st core, 5b 2nd core, 5c Conventional core, 6 slots, 7 (7a-7d) Magnetic pole teeth, 7e Conventional Magnetic pole teeth, 8 coils, 9 outer periphery of magnetic teeth, 9a-9d fixed piece, 9e-9h conventional fixed piece, 10 magnet insertion hole, 11 rare earth permanent magnet, 12 air gap, 13 rotor shaft, 14 notch, 15 Fastening caulking part for core lamination, 16 Protrusion for connecting magnetic pole teeth.

Claims (7)

Comprising a stator core formed by laminating doughnut-shaped cores formed by arranging magnetic teeth in the circumferential direction;
The magnetic pole teeth have a plurality of fixing pieces fixed to the housing on the outer peripheral portion in the circumferential direction,
A stator in which two or more types of magnetic pole teeth having different positions of the fixing pieces are stacked in the stacking direction. A sealed container provided as the housing;
A compression element that is provided in the sealed container and compresses the refrigerant; and an electric element that drives the compression element.
A hermetic compressor using the stator according to claim 1 as the electric element.   The hermetic compressor according to claim 2, wherein a permanent magnet type motor including a rotor having a permanent magnet is used as the electric element.   The hermetic compressor according to claim 3, wherein a rare earth permanent magnet is used as the permanent magnet.   The hermetic compressor according to any one of claims 2 to 4, wherein a coil is wound around each magnetic pole tooth of the stator core via an insulator.   A stator according to claim 1, a rotor provided in the hollow of the stator, and a coil wound around each magnetic pole tooth of the stator core via an insulator in a housing. A rotating machine characterized by that. Forming magnetic teeth after progressive punching of magnetic steel sheets, forming donut-shaped cores by combining the magnetic teeth in the final process, and stacking the cores to produce stator cores for stators In the mold to
In the plurality of punching steps, there are a plurality of types of fixed piece molding steps for forming different fixed pieces on the outer peripheral portion of the magnetic pole teeth for each core, and depending on the position of the fixed piece set arbitrarily in advance. A die characterized by intermittently punching a magnetic steel sheet that is fed in order and molding the magnetic pole teeth having different positions of fixed pieces for each core.

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