Motor for electric compressor and electric compressor having the same

Abstract

To provide a motor for an electric compressor capable of suppressing a decrease in life of an insulator, and the electric compressor including the motor.SOLUTION: A motor for an electric compressor comprises: a core of a stator; an insulator in contact with the core; and a winding wound around the insulator. The insulator is made of a resin material having a relative dielectric constant of 3.7 or less and a dielectric loss tangent of 0.0004 or less.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a motor for an electric compressor in which a winding is wound around an insulator attached to a core of a stator, and to an electric compressor including the motor. [Background technology]

[0002] Conventionally, a motor for driving a compression element of an electric compressor is composed of a stator and a rotor that rotates on the side of the stator. The stator is configured such that an insulator with a winding is attached to each of multiple teeth formed on a core (Patent Document 1). Furthermore, it has been proposed to use polyphenylene sulfide (PPS) or polybutylene terephthalate (PBT) as the material for the insulator (Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-126009 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-274360 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional techniques including those disclosed in Patent Documents 1 and 2, there is room for further improvement in terms of suppressing the shortening of the life of the insulator.

[0005] An object of the present invention is to provide a motor for an electric compressor that can suppress a decrease in the lifespan of an insulator, and an electric compressor including the motor. [Means for solving the problem]

[0006] After extensive research, the inventors discovered that when a resin whose relative dielectric constant and dielectric tangent meet certain conditions is used in an insulator, the reduction in the insulator's lifespan can be significantly suppressed, and thus completed the present invention. According to the present invention, the following motor for an electric compressor and the like can be provided.

[0007] A motor for an electric compressor according to one embodiment of the present invention comprises a stator core, an insulator in contact with the core, and a winding wound around the insulator, wherein the insulator is made of a resin material having a relative dielectric constant of 3.7 or less and a dielectric dissipation factor of 0.0004 or less. According to the motor for an electric compressor according to this aspect, it is possible to suppress a decrease in the lifespan of the insulator.

[0008] More preferably, the temperature rise of the insulator due to vibration is 1.5° C. or less, thereby more suitably suppressing a decrease in the lifespan of the insulator.

[0009] More preferably, the resin material contains syndiotactic polystyrene, which can more suitably suppress a decrease in the life span of the insulator.

[0010] An electric compressor according to one aspect of the present invention includes the electric compressor motor according to one aspect of the present invention. According to the electric compressor of this aspect, it is possible to suppress a decrease in the lifespan of the insulator. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a motor for an electric compressor that can suppress a decrease in the lifespan of an insulator, and an electric compressor including the motor. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a vertical cross-sectional side view of an electric compressor according to an embodiment of the present invention, which includes an electric compressor motor according to an embodiment of the present invention. [Figure 2]FIG. [Figure 3] FIG. [Figure 4] 10A and 10B are diagrams illustrating vibration of an insulator. DETAILED DESCRIPTION OF THE INVENTION

[0013] The motor for an electric compressor and the electric compressor including the motor according to the present invention will be described in detail below. In this specification, "x to y" represents a numerical range of "not less than x and not more than y." The upper and lower limits of the numerical ranges can be combined in any way. Furthermore, among the individual embodiments of the aspects of the present invention described below, it is possible to combine two or more embodiments that are not mutually contradictory, and an embodiment that combines two or more embodiments is also an embodiment of an aspect of the present invention.

[0014] A motor for an electric compressor according to one embodiment of the present invention comprises a stator core, an insulator attached to the outer surface of the teeth of the core, and a winding wound around the outer surface of the insulator, wherein the insulator is made of a resin material having a relative dielectric constant of 3.7 or less and a dielectric dissipation factor of 0.0004 or less. An electric compressor according to an aspect of the present invention includes the electric compressor motor according to an aspect of the present invention. These electric compressor motors and electric compressors have the effect of suppressing a decrease in the lifespan of the insulator.

[0015] The reason why the above-mentioned effects are exhibited is not entirely clear, but is presumed to be as follows. In the electric compressor motor provided in the electric compressor, vibration occurs in the insulator (the reason for vibration will be described later). When the electric compressor is in use, the insulator is at a high temperature (for example, it may be about 150°C), and this vibration can further increase the temperature of the insulator. Until now, there has been no established technology to suppress the shortening of the insulator's lifespan due to the temperature increase caused by such vibration. In response to this, the inventors have discovered that the above-mentioned shortening of life can be suppressed by including a resin in the insulator with a dielectric constant of 3.7 or less and a dielectric dissipation factor of 0.0004 or less. More specifically, it has been found that these parameters related to electrical properties (dielectric constant and dielectric dissipation factor) are extremely effective in suppressing heat generation (temperature rise) associated with physical (macro) vibration. As a result, the temperature rise of the insulator is suppressed, thereby suitably suppressing shortening of life.

[0016] In one embodiment, the insulator has a temperature rise due to vibration of 1.5° C. or less, 1.4° C. or less, 1.3° C. or less, 1.2° C. or less, 1.1° C. or less, 1.0° C. or less, 0.9° C. or less, 0.8° C. or less, 0.7° C. or less, 0.6° C. or less, 0.5° C. or less, 0.4° C. or less, 0.3° C. or less, 0.2° C. or less, or 0.1° C. or less. The lower limit is not particularly limited and can be, for example, 0.0° C. The lower the temperature rise due to vibration, the more pronounced the effect of suppressing the shortening of the life span. The "temperature rise due to vibration" is a value measured by the method described in the examples.

[0017] In one embodiment, the insulator has a lifespan reduction rate due to temperature rise caused by vibration of 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, or 1% or less. The lower limit is not particularly limited and can be, for example, 0%. The "lifespan reduction rate due to temperature rise caused by vibration" is a value measured by the method described in the examples.

[0018] The resin material constituting the insulator may contain a resin having a relative dielectric constant of 3.7 or less and a dielectric loss tangent of 0.0004 or less. Examples of resins that satisfy these conditions include, but are not limited to, syndiotactic polystyrene and polycarbonate. In one embodiment, the insulator comprises syndiotactic polystyrene. Syndiotactic polystyrene is a polystyrene having a syndiotactic structure, which is a thermoplastic crystalline resin having a three-dimensional structure in which phenyl groups, which are side chains, are arranged regularly so that they are alternately positioned in opposite directions relative to the main chain formed from carbon-carbon bonds. A method for producing syndiotactic polystyrene is described in, for example, JP-A-62-104818. In addition, a commercially available product such as Xalec (registered trademark) manufactured by Idemitsu Kosan Co., Ltd. can be used.

[0019] The resin material may contain only resins having a relative dielectric constant of 3.7 or less and a dielectric dissipation factor of 0.0004 or less, or may contain in combination with resins that do not satisfy these conditions (i.e., one or both of the relative dielectric constant and the dielectric dissipation factor do not satisfy these conditions) (for example, as a polymer alloy, etc.). In one embodiment, 50% by mass or more, 60% by mass or more, 70% by mass or more, 75% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, 99% by mass or more, 99.5% by mass or more, 99.9% by mass or more, or 100% by mass of the resin contained in the resin material constituting the insulator is a resin having a relative dielectric constant of 3.7 or less and a dielectric dissipation factor of 0.0004 or less. This more significantly exhibits the effect of suppressing a decrease in lifespan. In one embodiment, the resin material constituting the insulator contains resins that do not satisfy the conditions of a relative dielectric constant of 3.7 or less and a dielectric dissipation factor of 0.0004 or less (for example, one or more resins selected from the group consisting of polyamide 66, polybutylene terephthalate, polyarylene sulfide (for example, polyphenylene sulfide), and liquid crystal polymers) at a ratio of 25% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, 3% by mass or less, 2% by mass or less, 1% by mass or less, 0.5% by mass or less, or 0.1% by mass or less. This more significantly reduces the effect of reducing the lifespan. It is preferable that the resin contained in the resin material constituting the insulator consists solely of resin with a relative dielectric constant of 3.7 or less and a dielectric dissipation factor of 0.0004 or less. This more significantly suppresses the reduction in lifespan. It also simplifies the insulator manufacturing process, resulting in improved production efficiency. Furthermore, when the resin contained in the resin material constituting the insulator contains a high concentration of syndiotactic polystyrene (for example, 75% by mass or more), more preferably when the resin consists solely of syndiotactic polystyrene, not only is the effect of suppressing a decrease in lifespan more pronounced, but the weight of the insulator can also be reduced.

[0020] The resin material that constitutes the insulator may or may not contain components other than resin. Examples of components other than resin include fillers such as glass fibers, and additives such as flame retardants (bromine-based, phosphorus-based, etc.). In one embodiment, 50% by mass or more, 60% by mass or more, 70% by mass or more, 75% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, 99% by mass or more, 99.5% by mass or more, 99.9% by mass or more, or 100% by mass of the insulator is resin.

[0021] The invention will now be described in more detail with reference to the drawings. FIG. 1 is a longitudinal side view of an electric compressor 1 according to an embodiment of the present invention, which is equipped with an electric compressor motor 4 according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of a stator 21 of the electric compressor motor 4, and FIG. 3 is a perspective view of the stator 21.

[0022] 1 illustrates a scroll-type electric compressor 1. The electric compressor 1 includes a container 2 housing a scroll compression element 3, which is an example of a compression element, and an electric compressor motor 4.

[0023] The scroll compression element 3 comprises a fixed scroll 6 fixed to the container 2 and a movable scroll 7 that revolves without rotating relative to the fixed scroll 6 by a rotary shaft 8 of the electric compressor motor 4. Here, a spiral wrap 11 formed on the fixed scroll 6 and a spiral wrap 12 formed on the movable scroll are arranged to mesh with each other.

[0024] A refrigerant is introduced into the container 2 through a refrigerant introduction passage (not shown). The refrigerant is drawn from the outside into the compression chamber defined between the wraps 11 and 12. The compression chamber narrows toward the center due to the orbital motion of the movable scroll 7, so the drawn refrigerant is compressed and discharged from the center through the discharge chamber 14 and a refrigerant discharge passage (not shown). Furthermore, because the pressure inside the container 2 is low, the refrigerant also passes around the electric compressor motor 4, cooling the electric compressor motor 4.

[0025] The electric compressor motor 4 is a permanent magnet synchronous motor, and is composed of a stator 21 consisting of a core 22 and windings 23, and a magnet-embedded rotor 24 (made of multiple laminated electromagnetic steel plates) that is fixed to the rotating shaft 8 and rotates inside the stator 21.

[0026] The core 22 of the stator 21 is formed in a cylindrical shape and is made by laminating and bonding a plurality of electromagnetic steel plates. A plurality of teeth 27 (corresponding to the number of poles; 12 in this example) are provided inside the core 22.

[0027] The winding 23 is wound around insulators (bobbins) made of insulating material (first insulator 33a and second insulator 33b in this example). Specifically, the winding 23 is wound around these insulators 33a and 33b so as to span between a winding portion 37a of the first insulator 33a arranged on one side (here, the upper side) of the core 22 and a winding portion 37b of the second insulator 33b arranged on the other side (here, the lower side) of the core 22.

[0028] Between the first insulator 33a and the second insulator 33b, the winding 23 is housed between the teeth 27, 27 of the core 22. An insulation film (not shown) is provided on the surface of the core 22 between the teeth 27, 27 (the surface that may come into contact with the winding 23), thereby ensuring insulation. In this way, a magnetic path is formed. Each winding 23 is wired so as to form a predetermined electric circuit.

[0029] As described above, in this embodiment, in the motor 4 for an electric compressor, the insulators (first insulator 33a and second insulator 33b in this example) in contact with the core 22 of the stator 21, and the windings 23 wound around the insulators are made of a resin material with a relative dielectric constant of 3.7 or less and a dielectric loss tangent of 0.0004 or less. This can prevent a decrease in the lifespan of the insulators.

[0030] This will be described with reference to Fig. 4. Fig. 4 is an enlarged cross-sectional view of a contact portion between the first insulator 33a and the core 22, illustrating vibration of the insulator. The first insulator 33a is in contact with the upper part of the core 22. Although not shown in Fig. 4, the second insulator 33b is in contact with the lower part of the core 22. These insulators 33a and 33b are pressed against the core 22 side by the winding 23 being wound thereon. An electric compressor motor may be used in an environment where vibration occurs, such as when it is mounted in the engine compartment of an automobile. Therefore, vibration occurs in the insulators 33a and 33b. However, by using a resin material with a relative permittivity of 3.7 or less and a dielectric dissipation factor of 0.0004 or less for the insulators, heat generation (temperature rise) due to vibration can be suppressed, as described above. As a result, the lifespan of the insulators can be reduced. In particular, stress tends to concentrate in the area of ​​the insulator indicated by the symbol P (the outer peripheral area at the bottom of the winding portion 37a). However, even if such stress concentrates, the reduction in the lifespan of the insulator is suppressed, and the inherent strength of the resin material is suitably demonstrated over a long period of time, making it less likely for insulation breakdown to occur (improving insulation reliability).

[0031] In the above description, the insulator is mainly composed of the first insulator 33a and the second insulator 33b (i.e., composed of two independent members), but this is not limiting. The insulator may be composed of, for example, a single member. In this case, for example, the first insulator 33a and the second insulator 33b may be integrally connected by a connecting portion (not shown).

[0032] In the above description, the method for producing the insulator is not particularly limited, and the insulator can be produced, for example, by injection molding the above-mentioned resin material. Furthermore, the shapes and configurations of the elements constituting the electric compressor, such as the insulators and core, are not limited to those described above, and may take any known shape and configuration.

[0033] Although the above description has been given mainly on the case where the electric compressor is a scroll electric compressor, the present invention is not limited to this. However, the electric compressor motor according to one aspect of the present invention can be suitably used for various electric compressors, such as rotary electric compressors. [Example]

[0034] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0035] 1. Resin materials for insulators Example 1 As a resin material, syndiotactic polystyrene (abbreviated as "SPS", manufactured by Idemitsu Kosan Co., Ltd., Xarec (registered trademark) S136) was prepared.

[0036] Example 2 In Example 1, polycarbonate (abbreviated as "PC", manufactured by Teijin Limited, Panlite (registered trademark) AM-1300E) was prepared in place of the syndiotactic polystyrene.

[0037] (Comparative Example 1) In Example 1, polyamide 66 (abbreviated as "PA66", manufactured by BASF, Ultramid (registered trademark) A3HG6) was prepared in place of the syndiotactic polystyrene.

[0038] (Comparative Example 2) In Example 1, polybutylene terephthalate (abbreviated as "PBT", manufactured by Polyplastics Co., Ltd., DURANEX (registered trademark) 330LC) was prepared in place of the syndiotactic polystyrene.

[0039] (Comparative Example 3) In Example 1, polyphenylene sulfide (abbreviated as "PPS", manufactured by Polyplastics Co., Ltd., DURAFIDE (registered trademark) 1140A6) was prepared in place of the syndiotactic polystyrene.

[0040] Comparative Example 4 In Example 1, a liquid crystal polymer (abbreviated as "LCP", manufactured by Ueno Pharmaceutical Co., Ltd., UENO LCP 5030G) was prepared in place of the syndiotactic polystyrene.

[0041] 2. Measurement of relative permittivity and dielectric loss tangent The relative permittivity and dielectric loss tangent of the resin materials prepared in each of the examples and comparative examples were measured under the following measurement conditions. The results are shown in Table 1. <Measurement conditions> ·Complies with JIS C 2138 (automatic balancing bridge method) Sample dimensions: 50 x 30 x t3 (mm) Measurement environment: 23°C, 50% RH Electrode dimensions: Main electrode diameter φ14mm, ring electrode inner diameter φ16mm Frequency: 100Hz Electrode material: In Example 1 and Comparative Examples 1 to 4, conductive silver paint was used, and in Example 2, tin foil was used. Number of measurements: n=2 Measurement equipment: Precision LCR meter E4980A (Agilent Technologies)

[0042] [Table 1]

[0043] 3. Vibration test The resin materials prepared in each of the examples and comparative examples were subjected to a cantilever bending vibration fatigue test in accordance with JIS K 7118 and JIS K 7119. The test conditions were as follows. <Test conditions> Testing machine: Toyo Seiki Co., Ltd., repeated vibration fatigue testing machine, B-50 (1 mm spacers were used for the fixed and movable parts.) Stress conditions: The stress was set to a value that resulted in a strain of 0.2 for each material. Test environment: 23°C, 50% RH Test frequency: 30Hz (fixed) Stress ratio: R=-1 (double swing)

[0044] In the above test, the temperature of the test piece (made of a resin material) was measured immediately after the start of vibration. The temperature was measured using a radiation temperature sensor (specifically, FT-H40K, NR-500, NR-HA08, and FT-50 manufactured by Keyence Corporation). The temperature rise of the test piece during the test is shown in Table 2. This temperature rise is the value obtained by subtracting the temperature at the start of vibration from the temperature one hour after the start of vibration. Note that the temperature was constant one hour after the start of vibration. Table 2 also shows the operating temperature of the electric compressor (assumed to be 150°C) and the sum of the temperature rise (corresponding to the temperature during actual use), the predicted lifespan (assumed to be 1000 hours at 150°C), and the rate of reduction in lifespan due to temperature rise. The predicted lifespan was calculated based on the 10°C doubling rule. The 10°C doubling rule is expressed by the following formula, and is an empirical rule that states that, for example, if the temperature rises by 10°C, the speed of deterioration and the lifespan will decrease by two times (deterioration will double). In the formula below, L is the predicted lifespan, L0 is the measured temperature (here, 1000 hours), T is the assumed temperature (here, the sum of the ambient temperature in which the electric compressor is used and the increased temperature), and T0 is the measured temperature (here, 150°C).

[0045]

number

[0046] [Table 2]

[0047] Tables 1 and 2 show that when a resin material with a relative dielectric constant of 3.7 or less and a dielectric dissipation factor of 0.0004 or less is used as the resin material for an insulator, the temperature rise caused by vibration is significantly suppressed and the original lifespan is maintained optimally. [Industrial Applicability]

[0048] The motor for an electric compressor of the present invention can be suitably used in an electric compressor that is installed in an environment where vibrations may occur, such as the engine compartment of an automobile. [Explanation of symbols]

[0049] 1: Electric compressor 2: Container 3: Scroll compression element 4: Electric compressor motor 6: Fixed scrolling 7: Movable scroll 8: Rotation axis 11, 12: Rap 14:Discharge chamber 21: Stator 22: Core 23: Winding 24:Rotor 27: Teeth 33a: (first) insulator 33b: (Second) Insulator 37a, 37b: Winding section

Claims

1. The stator comprises a core, an insulator in contact with the core, and a winding wound around the insulator, The motor for an electric compressor, wherein the insulator is made of a resin material having a relative dielectric constant of 3.7 or less and a dielectric loss tangent of 0.0004 or less.

2. 2. The motor for an electric compressor according to claim 1, wherein the insulator has a temperature rise due to vibration of 1.5° C. or less.

3. 3. The motor for an electric compressor according to claim 1, wherein the resin material contains syndiotactic polystyrene.

4. An electric compressor comprising the motor for an electric compressor according to claim 1.

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