Stator division body, stator and motor

Abstract

The present invention provides stator split bodies which each enable iron loss to be reduced more than conventional products and which facilitate dimension accuracy control.　Stator split bodies (22) are each disposed in the circumferential direction in a split manner, a stator (20) to which a compression force is applied radially inward from a case (40) in a fitted state of being fitted to the inside of the case (40). The stator split bodies (22) have: split cores (26) that each have a yoke and teeth and that are each obtained by splitting, in the circumferential direction, a stator core (24); coils (28) into which the teeth are inserted and which are disposed in a non-contact state with respect to the split cores (26); and mold resin parts 30 formed with the coils (28) being embedded therein. The mold resin parts (30) each receive a compression force in the circumferential direction in the fitted state.

Description

[Technical field]

[0001] The present invention relates to a motor, and more particularly to a stator and a stator segment which is one of a plurality of segments obtained by dividing the stator in the circumferential direction. [Background technology]

[0002] Japanese Patent No. 5181994 describes a split stator (split stator) formed by combining in the circumferential direction a number of stator pieces (stator pieces), each of which has a yoke portion extending in the circumferential direction and a tooth portion extending in the radial direction from the yoke portion. In this split stator, two slits are formed in each of the yoke portions of the stator pieces, extending in the circumferential direction from both end faces in the circumferential direction of the yoke portion. This allows the stress generated when the stator pieces are placed in a case to be concentrated in the area between the two slits, thereby reducing iron loss, which is a cause of reduced efficiency of the motor.

[0003] Japanese Patent Publication No. 2006-333657 discloses a motor having a stator unit in which a stator core formed by stacking a plurality of core plates is housed in a case, and a rotor that is rotatable relative to the stator unit. In this motor, the stator core is composed of a first portion and a second portion that is fixed so as to overlap both ends of the first portion in the axial direction. The first portion is composed of stacked core plates having an outer diameter smaller than the inner diameter of the case. The core plate that constitutes the second portion has a base portion having the same outer diameter as the core plate that constitutes the first portion, and a plurality of protrusions that extend from the outer periphery of the base portion. The stator core and the case are brought into contact only through these protrusions, thereby reducing the area in the stator core where stress acts. Summary of the Invention [Problem to be solved by the invention]

[0004] In the prior art described in Japanese Patent No. 5181994, depending on the dimensional accuracy of the case and stator core, the circumferential end faces of the yoke parts on the inner diameter side of adjacent stator pieces may come into strong contact with each other, which may cause compressive stress in the circumferential direction, and in order to prevent this, strict dimensional accuracy control is required. However, it is very difficult to control dimensional accuracy in mass production, and even if it is possible, it will cause an increase in manufacturing costs.

[0005] In the prior art described in Japanese Patent Publication No. 2006-333657, the multiple protrusions extending from the outer periphery of the base of the core plate constituting the second portion have high radial rigidity at the portion connected to the base. Therefore, depending on the dimensional accuracy of the case and each protrusion, the radial load that each protrusion receives from the case may be transmitted to the base of the core plate, generating high compressive stress in the base (yoke portion) of the core plate, which may increase iron loss.

[0006] In consideration of the above, an object of the present invention is to provide a stator segment, a stator, and a motor that can reduce iron loss more than ever before and that can easily control dimensional accuracy. [Means for solving the problem]

[0007] The stator split body of the first embodiment is a stator split body in which a stator is one of several pieces divided in the circumferential direction and which receives a radially inward compressive force from the case when fitted inside the case, and the stator core is one of several pieces divided in the circumferential direction, and is equipped with a split core having a yoke portion and teeth portion, a coil into which the teeth portion is inserted and which is arranged in a non-contact state with respect to the split core, and a molded resin portion in which the coil is molded so as to be embedded inside and which receives the circumferential compressive force in the fitted state.

[0008] The stator split body of the first aspect is one of a plurality of circumferentially divided stators that receive a radially inward compressive force from the case when fitted inside the case. This stator split body is one of a plurality of circumferentially divided stator cores, and includes a split core having a yoke portion and a teeth portion, a coil in which the teeth portion is inserted inside and is arranged in a non-contact state with the split core, and a molded resin portion molded in a state in which the coil is embedded inside. This molded resin portion receives the circumferential compressive force in the fitted state. This makes it possible to prevent or suppress the occurrence of the circumferential compressive stress in the yoke portion of the split core, thereby reducing iron loss. Moreover, the molded resin constituting the molded resin portion has a lower rigidity than the split core, and can absorb dimensional variations. This makes it easier to control dimensional accuracy.

[0009] A stator segment of a second aspect is the stator segment of the first aspect, wherein the molded resin portion protrudes outward in the circumferential direction beyond the yoke portion.

[0010] In the second aspect of the stator segments, the molded resin parts protrude further outward in the circumferential direction of the stator than the yoke parts of the split cores. Therefore, when a stator consisting of multiple stator segments is fitted inside a case, the protruding molded resin parts come into contact with each other in the circumferential direction as described above, thereby preventing or suppressing the yoke parts of the split cores from coming into contact with each other in the circumferential direction. This effectively prevents or suppresses the generation of the circumferential compressive stress in the yoke parts of the split cores.

[0011] A stator segment of a third aspect is the stator segment of the first aspect, wherein an elastic member is interposed between the molded resin portion and another molded resin portion adjacent to the molded resin portion in the circumferential direction in the fitted state.

[0012] In the third aspect of the stator segments, when the stator consisting of the multiple stator segments is fitted inside the case, the elastic member receives the circumferential compressive force of the stator, which effectively prevents or suppresses the circumferential compressive stress from being generated in the yoke portions of the split cores.

[0013] A stator split body of a fourth aspect is the stator split body of the third aspect, wherein the elastic member is attached to the molded resin portion.

[0014] In the stator segments of the fourth aspect, the elastic member is attached to the molded resin portion, which facilitates the work of fitting the stator made up of a plurality of stator segments into the inside of the case.

[0015] A stator according to a fifth aspect of the invention includes a plurality of stator segments according to any one of the first to fourth aspects, the plurality of stator segments being arranged in an annular shape.

[0016] The stator of the fifth aspect is configured by arranging a plurality of stator segments in an annular shape. Since the plurality of stator segments are any one of the first to fourth aspects, the above-mentioned functions and effects can be obtained.

[0017] The stator of the sixth aspect is a stator that is fitted inside a case and receives a radially inward compressive force from the case in a fitted state, and includes a stator core formed by arranging a plurality of split cores in a circular ring shape, each of which has a yoke portion and a teeth portion, a plurality of coils into which each of the teeth portions is inserted and which are arranged in a non-contact state with respect to each of the split cores, and a plurality of molded resin portions which are molded so that each of the coils is embedded inside, which join the plurality of split cores together, and which receive the circumferential compressive force in the fitted state.

[0018] The stator of the sixth aspect receives a radially inward compressive force from the case in a fitted state in which it is fitted inside the case. This stator includes a stator core formed by arranging a plurality of split cores, each having a yoke portion and a tooth portion, in an annular shape, a plurality of coils in which the tooth portions are inserted inside and arranged in a non-contact state with the split cores, and a plurality of molded resin portions molded in a state in which the coils are embedded inside. These molded resin portions integrally join the plurality of split cores and receive the circumferential compressive force in the fitted state. This makes it possible to prevent or suppress the generation of the circumferential compressive stress in the yoke portions of each split core, thereby reducing iron loss. Moreover, the molded resin constituting each molded resin portion has a lower rigidity than each split core, and therefore can absorb dimensional variations. This makes it easier to manage dimensional accuracy.

[0019] A seventh aspect of the stator is the stator according to the fifth or sixth aspect, wherein a gap is formed between each of the yoke portions of the plurality of split cores adjacent in the circumferential direction of the stator core.

[0020] In the seventh aspect of the stator, a gap is formed between each yoke portion of the multiple split cores adjacent in the circumferential direction of the stator core, thereby making it possible to prevent the above-mentioned compressive stress in the circumferential direction from occurring in each yoke portion.

[0021] The motor of an eighth aspect includes a case, a stator of any one of the fifth to seventh aspects that is fitted inside the case, and a rotor that has a permanent magnet and is arranged inside the stator.

[0022] In the motor of the eighth aspect, a stator is fitted inside the case, and a rotor having a permanent magnet is disposed inside the stator. The stator is any one of the first to seventh aspects, and therefore the above-mentioned functions and effects can be obtained.

[0023] The motor of the 9th aspect of the invention is the motor of the 8th aspect which references the 7th aspect, and is configured such that, when the circumferential dimension of the gap is a, the radial dimension of the gap between the stator and the rotor is b, and the thickness dimension of the permanent magnet in the magnetization direction is c, the relationship a / (b+c)<0.07 holds.

[0024] In the motor of the ninth aspect, a gap is formed between each yoke portion of the multiple split cores adjacent in the circumferential direction of the stator core. If the circumferential dimension of this gap is a, the radial dimension of the gap between the rotor and the stator is b, and the thickness dimension in the magnetization direction of the permanent magnet of the rotor is c, the relationship of a / (b+c)<0.07 is established. By configuring in this way, the efficiency of this motor can be improved. In other words, since the magnetic resistance increases due to the gap, it is necessary to increase the current flowing through the coil to compensate for the magnetic flux. As a result, the loss in the coil increases, but if the above relationship is established, the effect of reducing iron loss exceeds the increase in loss in the coil, so the total loss of the motor decreases. This allows the efficiency of this motor to be improved. Effect of the Invention

[0025] As described above, in the stator segment, stator, and motor according to the present invention, it is possible to reduce iron loss and to easily control the dimensional accuracy. [Brief description of the drawings]

[0026] [Figure 1] 1 is a cross-sectional view showing a configuration of a motor according to a first embodiment. [Diagram 2] 1 is a cross-sectional view showing a configuration of a stator split body according to a first embodiment. [Diagram 3] 1 is a cross-sectional view showing a configuration of a stator according to a first embodiment. [Figure 4] FIG. 3 is a diagram for explaining efficiency of the motor according to the first embodiment. [Diagram 5]FIG. 11 is a cross-sectional view showing a configuration of a stator split body according to a second embodiment. [Figure 6] FIG. 11 is a cross-sectional view showing the configuration of a stator according to a second embodiment. [Figure 7] FIG. 11 is a cross-sectional view showing a configuration of a stator segment according to a third embodiment. [Figure 8] FIG. 11 is a cross-sectional view showing the configuration of a stator according to a third embodiment. [Figure 9] FIG. 11 is a cross-sectional view showing a configuration of a stator according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] <First embodiment> A motor 10 according to a first embodiment of the present invention will be described below with reference to Figures 1 to 4. Note that in each figure, some reference numerals may be omitted in order to make the drawings easier to understand.

[0028] 1, the motor 10 is an inner rotor type motor in which a rotor 12, which is a field magnet, is coaxially disposed inside a stator 20, which is an armature. The rotor 12 and the stator 20 are coaxially housed in a case 40 formed in a cylindrical shape with a bottom.

[0029] A rotating shaft 14 is provided at the center of the rotor 12, and a plurality of (four here) permanent magnets 16 are provided on the outer periphery of the rotor 12. The plurality of permanent magnets 16 are arranged side by side in the circumferential direction of the rotor 12, and are inserted into the inside of a plurality of (four here) magnet insertion holes (reference numbers omitted) formed on the outer periphery of the rotor 12. These permanent magnets 16 are long rectangular when viewed from the axial direction of the rotor 12, and are arranged with their short sides aligned along the radial direction of the rotor 12. The short side direction of each permanent magnet 16 is the magnetization direction.

[0030] The stator 20 is configured by arranging a plurality of (six in this case) stator segments 22 in an annular shape. As shown in FIG. 2, the stator segment 22 is one of a plurality of (six in this case) equal segments obtained by dividing the stator 20 in the circumferential direction. The stator segment 22 includes a split core 26, a coil 28, and a molded resin portion 30. The split core 26 is one of a plurality of (six in this case) equal segments obtained by dividing the stator core 24 shown in FIG. 1 and FIG. 3 in the circumferential direction. The circumferential direction of the stator 20 is the same as the circumferential direction of the stator core 24. In the following description, the circumferential direction of the stator 20 may be simply referred to as the "circumferential direction".

[0031] The split core 26 is composed of a yoke portion 26A (reference numeral omitted in figures other than FIG. 2) extending in the circumferential direction of the stator 20, and teeth portions 26B (reference numeral omitted in figures other than FIG. 2) extending from the yoke portion 26A toward the radially inward direction of the stator 20. The split core 26 composed of the yoke portion 26A and the teeth portions 26B is substantially T-shaped when viewed from the axial direction of the stator 20. The split core 26 is composed of a plurality of iron core pieces made of electromagnetic steel sheets stacked one on top of the other. The split core 26 may be formed by compacting magnetic metal powder.

[0032] The coil 28 is formed by winding a wire 29. The wire 29 is, for example, a wire material made of copper, aluminum, silver, or an alloy thereof, covered (coated) with an insulating film. The wire 29 is a rectangular wire here, but may be a round wire, a hexagonal wire, or the like. The coil 28 is composed of a winding portion 28A wound in a long elliptical shape with the axial direction of the stator 20 as its longitudinal direction, and a pair of coil end portions (not shown) extending from one longitudinal end side of the winding portion 28A. The coils 28 of each stator divided body 22 are configured such that the coil end portions are connected to each other by a predetermined wiring method.

[0033] The coil 28 is disposed so that the teeth 26B of the split core 26 are inserted inside (i.e., inside the winding portion 28A) of the coil 28 and is not in contact with the yoke portion 26A and the teeth 26B of the split core 26. Most of the coil 28, except for the tip sides of a pair of coil end portions, is embedded in a molded resin portion 30 molded into the split core 26.

[0034] The molded resin part 30 is a material obtained by kneading a powder of a non-magnetic material as a filler into a thermosetting resin such as an epoxy resin or a thermoplastic resin, and has thermal conductivity and insulation properties. The molded resin part 30 is molded in a state in which the coil 28 is embedded inside. In detail, the winding part 28A of the coil 28 and the base end side of the pair of coil end parts are covered from the outside by the molded resin part 30. The molded resin part 30 is also filled between the split core 26 and the coil 28 and between the wires 29 of the coil 28. By providing the molded resin part 30, heat generated in the coil 28 is transferred to the case 40 via the split core 26 and dissipated from the case 40. This improves the cooling performance of the coil 28.

[0035] The molded resin portion 30 is, for example, made of a single molded resin, and no resin portion molded separately from the molded resin portion 30 exists between the split core 26 and the coil 28 and between the wires 29 of the coil 28. That is, in this embodiment, only the resin molded by one injection molding exists between the split core 26 and the coil 28 and between the wires 29 of the coil 28. The molded resin portion 30 is configured such that there is no portion where the resin filled between the split core 26 and the coil 28 and the resin filled between the wires 29 of the coil 28 are thermally welded (thermally fused) to each other. Note that the molded resin portion 30 is not limited to the above-mentioned configuration in which the molded resin portion 30 is molded integrally with the split core 26 and the coil 28. For example, the molded resin portion 30 may be molded after an insulator is attached to the split core 26 and then the coil 28 is wound around the split core 26.

[0036] The molded resin portion 30 is set to have a longer length in the axial direction of the stator 20 than the split core 26, and protrudes on both sides in the axial direction relative to the split core 26. The molded resin portion 30 is generally trapezoidal (generally sectorial) when viewed in the axial direction, and both circumferential end faces 31 (reference numbers omitted in figures other than FIG. 2) are inclined at the same angle as both circumferential end faces 27 (reference numbers omitted in figures other than FIG. 2) of the yoke portion 26A.

[0037] However, both circumferential end faces 31 of molded resin portion 30 protrude slightly outward in the circumferential direction beyond both circumferential end faces 27 of yoke portion 26A. That is, molded resin portion 30 protrudes outward in the circumferential direction beyond yoke portion 26A. Furthermore, the tips of teeth portion 26B are exposed to the outside of molded resin portion 30. Note that in FIG. 2, the above-mentioned protrusion of molded resin portion 30 is exaggerated.

[0038] The stator 20, which includes a plurality of stator segments 22 configured as described above, is configured by arranging the plurality of stator segments 22 in an annular shape, as shown in Fig. 1 and Fig. 3. The stator 20 is fitted inside the case 40 by means of press fitting, shrink fitting, or the like. The outer diameter dimension of the stator 20 and the inner diameter dimension of the case 40 are set so that, in this fitted state, the stator 20 receives a radially inward compressive force CF (see Fig. 3; not shown in Fig. 1) from the case 40. The stator 20 is fixed to the case 40 by the compressive force CF. That is, in this embodiment, the stator 20 is fixed to the case 40 by a so-called interference fit.

[0039] In addition, in the above-mentioned fitted state, the molded resin portion 30 of each stator segment 22 is configured to receive a circumferential compressive force (not shown). That is, in the above-mentioned fitted state, the molded resin portions 30 of the stator segments 22 adjacent to each other in the circumferential direction are pressed against each other in the circumferential direction, thereby generating the above-mentioned circumferential compressive force.

[0040] In addition, in this embodiment, as described above, in each stator divided body 22, the molded resin portion 30 protrudes outward on both sides in the circumferential direction from the yoke portion 26A, so that in the above-mentioned fitted state, a gap 32 (see FIG. 1 and FIG. 3) is formed between the yoke portions 26A of the divided cores 26 adjacent in the circumferential direction. As shown in FIG. 1, when the circumferential dimension of the gap 32 is a, the radial dimension of the gap 34 between the stator 20 and the rotor 12 is b, and the thickness dimension in the magnetization direction of the permanent magnet 16 is c, the relationship a / (b+c)<0.07 is established. That is, the above-mentioned a is set to less than 7% of b+c. Note that, as described above, the configuration is not limited to the molded resin portion 30 protruding outward on both sides in the circumferential direction from the yoke portion 26A in each stator divided body 22. In each stator divided body 22, the molded resin portion 30 may be configured to protrude only on one side in the circumferential direction from the yoke portion 26A. Even in this case, by adjusting the amount of overhang to one side of the molded resin portion 30, a gap 32 can be formed between the yoke portions 26A of the split cores 26 adjacent to each other in the circumferential direction.

[0041] (Action and Effects) Next, the operation and effects of this embodiment will be described.

[0042] In the motor 10 configured as described above, the stator 20 is fitted inside the case 40, and the rotor 12 is disposed inside the stator 20. The stator 20 is configured by arranging a plurality of stator segments 22 in an annular shape. Each stator segment 22 includes a split core 26, a coil 28, and a molded resin portion 30. The split coil 28 is one of the segments obtained by dividing the stator core 24 in the circumferential direction, and includes a yoke portion 26A and teeth portions 26B. The coil 28 is disposed with the teeth portions 26B inserted inside and out of contact with the split core 26. The molded resin portion 30 is molded with the coil 28 embedded therein.

[0043] In this motor 10, in the fitted state in which the stator 20 is fitted inside the case 40 as described above, the stator 20 receives a radially inward compressive force CF from the case 40. As a result, the molded resin portion 30 of each stator split body 22 receives a circumferential compressive force. This makes it possible to prevent or suppress the generation of circumferential compressive stress in the yoke portion 26A of the split core 26.

[0044] In detail, in this embodiment, each molded resin portion 30 protrudes outward in the circumferential direction from each yoke portion 26A. Therefore, in the above-mentioned fitted state, the molded resin portions 30 protruding in this way contact each other in the circumferential direction, forming gaps 32 between each yoke portion 26A, and preventing each yoke portion 26A from contacting each other in the circumferential direction. This makes it possible to prevent the occurrence of compressive stress in the circumferential direction in each yoke portion 26A, and therefore it is possible to significantly reduce iron loss, which causes a decrease in efficiency of the motor 10. Moreover, the molded resin constituting the molded resin portion 30 has lower rigidity (is more flexible) than the divided core 26, and therefore it is possible to absorb dimensional variations. This makes it easier to manage dimensional accuracy.

[0045] In this embodiment, the relationship a / (b+c)<0.07 is satisfied, where a is the circumferential dimension of the gap 32, b is the radial dimension of the gap 34 between the rotor 12 and the stator 20, and c is the thickness dimension of the permanent magnet 16 of the rotor 12 in the magnetization direction. With this configuration, the efficiency of the motor 10 can be improved.

[0046] In other words, because the gap 32 increases magnetic resistance, when outputting the same torque as a conventional motor, it is necessary to increase the current flowing through each coil 28 to compensate for the magnetic flux reduced by the increased magnetic resistance. As a result, loss in the coils 28 increases, but if the above relationship holds, the effect of reduced iron loss exceeds the increased loss in the coils 28, so the total loss of the motor 10 decreases. This makes it possible to improve the efficiency of the motor 10.

[0047] In addition, Fig. 4 shows a graph of the efficiency of motor 10 when a / (b+c) is changed in this embodiment. In Fig. 4, the dashed line indicates the efficiency of a conventional motor in which the stator is fixed to the case by so-called interference fit. In this conventional motor, a compressive stress of, for example, 20 MPa acts in the circumferential direction on the yoke portion of the stator core. As shown in Fig. 4, when a / (b+c) is smaller than 0.07, the efficiency of motor 10 becomes higher than the efficiency of the conventional motor.

[0048] To supplement the above effect, in conventional motors, when a cylindrical stator with a smooth outer periphery is fixed to a case, it is generally fixed by interference fit. In this case, a load is applied to the outer periphery of the stator core in the radially inward direction, so that a circumferential compressive stress is generated in the yoke of the stator core, which increases iron loss. Since the stator is fixed to the case by interference fit as described above, the above compressive stress is generated, and in order to reduce it as much as possible, strict dimensional accuracy is required. However, in reality, a certain amount of dimensional variation occurs in the stator core and the case. In addition, since the stator core and the case have high rigidity, the fixing force changes significantly due to a slight dimensional variation. Therefore, in some cases, there is a risk that the required fixing force cannot be obtained, but in order to prevent this, the stator core and the case are designed with a dimensional tolerance that ensures an interference fit that generates the required fixing force. In this case, when the interference fit is the maximum within the range of variation, an excessive fixing force acts on the stator core due to the interference fit that is greater than necessary, and the compressive stress in the yoke of the stator core increases, which increases the iron loss.

[0049] In this embodiment, the molded resin portion 30 of the stator split body 22 protrudes outward in the circumferential direction from the yoke portion 26A, and the circumferential compressive stress generated during the interference fit is borne by the molded resin portion 30, so that the circumferential compressive stress is not applied to the yoke portion 26A. This reduces iron loss and improves the performance of the motor 10, while absorbing dimensional variations with the molded resin portion 30, which has low rigidity, making it easier to control dimensional accuracy. Although a circumferential compressive stress is applied to the teeth portion 26B of the split core 26 via the molded resin portion 30, the main magnetic flux direction is the longitudinal direction of the teeth portion 26B (the radial direction of the stator 20) and is perpendicular to the compressive stress direction, so that the iron loss does not increase due to this compressive stress.

[0050] In the above first embodiment, the molded resin portion 30 protrudes outward in the circumferential direction beyond the yoke portion 26A, thereby forming the gap 32 between the circumferentially adjacent yoke portions 26A, but the present invention is not limited to this, and a configuration may be adopted in which no gap 32 is formed. Even in this case, the molded resin portion 30 receives a circumferential compressive force, thereby reducing the circumferential compressive stress generated in the yoke portion 26A, and therefore reducing iron loss.

[0051] Next, another embodiment of the present invention will be described. Note that the same reference numerals as in the already-described embodiment are used to designate configurations and operations that are basically similar to those in the already-described embodiment, and descriptions thereof will be omitted.

[0052] <Second embodiment> A stator segment 22 according to a second embodiment of the present invention is shown in a cross-sectional view in Fig. 5, and a stator 20 according to the second embodiment of the present invention is shown in a cross-sectional view in Fig. 6. The stator 20 and the stator segment 22 according to this embodiment are basically similar in configuration to the stator 20 and the stator segment 22 according to the first embodiment, but differ in the following respects.

[0053] In the stator split body 22 according to this embodiment, both circumferential end faces 31 of the molded resin portion 30 and both circumferential end faces 27 of the yoke portion 26A are disposed on the same plane. A recess 36 (reference numeral omitted in FIG. 6) recessed inward in the circumferential direction is formed in the circumferential end face 31 of the molded resin portion 30. An elastic member 42 is fitted and attached to the recess 36 on one circumferential side as shown in FIG. 5. The elastic member 42 is, for example, a leaf spring, a compression coil spring, or a resin having elasticity. The method of attaching the elastic member 42 to the recess 36 is not limited to fitting, and may be another method such as adhesion.

[0054] In the stator 20 in which a plurality of stator segments 22 having the above-described configuration are arranged in an annular shape, an elastic member 42 is interposed between circumferentially adjacent molded resin portions 30. When the stator 20 is fitted inside the case 40, the circumferentially adjacent molded resin portions 30 are subjected to a circumferential compressive force via the elastic member 42. Note that, while Fig. 6 shows an example in which no gap 32 is formed between circumferentially adjacent stator segments 22, the present invention is not limited to this, and a configuration in which a gap 32 is formed between circumferentially adjacent stator segments 22 may also be used.

[0055] However, even in this case, it is preferable to configure so that the relationship a / (b+c)<0.07 holds, where a is the circumferential dimension of gap 32, b is the radial dimension of gap 34 between rotor 12 (not shown in FIG. 6) and stator 20, and c is the thickness dimension in the magnetization direction of permanent magnet 16 of rotor 12. In this embodiment, the configuration other than the above is the same as that of the first embodiment.

[0056] In this embodiment, the molded resin portion 30 of each stator split body 22 receives a circumferential compressive force via the elastic member 42. This effectively prevents or suppresses the generation of circumferential compressive stress in the yoke portion 26A of the split core 26, and basically provides the same effects as in the first embodiment. Moreover, in this embodiment, the elastic member 42 is attached to the molded resin portion 30, which facilitates the work of fitting the stator 20 made up of multiple stator split bodies 22 into the inside of the case 40.

[0057] <Third embodiment> A stator segment 22 according to a third embodiment of the present invention is shown in a cross-sectional view in Fig. 7, and a stator 20 according to the third embodiment of the present invention is shown in a cross-sectional view in Fig. 8. The stator 20 and the stator segment 22 according to this embodiment are basically similar in configuration to the stator 20 and the stator segment 22 according to the first embodiment, but differ in the following respects.

[0058] In the stator division body 22 according to this embodiment, both end faces 31 in the circumferential direction of the molded resin portion 30 are recessed inward in the circumferential direction relative to both end faces 27 in the circumferential direction of the yoke portion 26A. An elastic member 44 is attached to one end face in the circumferential direction of the molded resin portion 30 by, for example, adhesion or other means. The elastic member 44 is, for example, a resin plate having elasticity, and is arranged in a position in which the plate thickness direction is along the circumferential direction. In a fitted state in which the stator 20 is fitted inside the case 40, the molded resin portions 30 adjacent in the circumferential direction are configured to receive a circumferential compressive force via the elastic member 44. Note that, in FIG. 6, an example in which the gap 32 is formed between the stator division bodies 22 adjacent in the circumferential direction is shown, but the present invention is not limited to this, and the gap 32 may not be formed between the stator division bodies 22 adjacent in the circumferential direction. In this embodiment, the configuration other than the above is the same as that of the first embodiment.

[0059] In this embodiment, the molded resin portion 30 of each stator segment 22 receives a compressive force in the circumferential direction via the elastic member 44. In this embodiment as well, it is possible to obtain basically the same effects as in the second embodiment.

[0060] <Fourth embodiment> FIG. 9 shows a cross-sectional view of a stator 20 according to a fourth embodiment of the present invention. The stator 20 according to this embodiment has a basically similar configuration to the stator 20 according to the first embodiment, but differs in the following points. In this stator 20, a plurality of split cores 26 (six in this case) are integrally joined by a plurality of molded resin parts 30 (six in this case). Note that FIG. 9 shows an example in which a gap 32 is formed between circumferentially adjacent stator split bodies 22. When manufacturing this stator 20, molding is performed in a state in which the split cores 26 are fixed in an annular shape using a jig so that the above-mentioned relationship a / (b+c)<0.07 is satisfied. In this embodiment, the configuration other than the above is the same as that of the first embodiment.

[0061] In this embodiment as well, in a fitted state in which the stator 20 is fitted inside the case 40, the stator 20 receives a radially inward compressive force CF from the case 40, and the multiple molded resin portions 30 receive a circumferential compressive force. This provides basically the same effects as the first embodiment.

[0062] In each of the above-described embodiments, the numbers of the split cores 26 and the molded resin portions 30 are merely examples and can be changed as appropriate.

[0063] In addition, the present invention can be practiced with various modifications without departing from the spirit and scope of the present invention. Furthermore, the scope of the present invention is not limited to the above-described embodiments.

[0064] In addition, the disclosure of Japanese Patent Application No. 2020-026637, filed on February 19, 2020, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. a stator divided into a plurality of stator segments, the stator being fitted into the inside of a case and receiving a radially inward compressive force from the case in a fitted state; the stator being one of a plurality of stator segments divided in a circumferential direction, a split core, the split core being one of a plurality of split cores in a circumferential direction of a stator core, the split core having a yoke portion and teeth portions; a coil having the teeth inserted inside and disposed in a non-contact state with respect to the split core; a molded resin portion that is molded with the coil embedded therein and that receives the circumferential compressive force in the fitted state; having The molded resin portion is a stator segment that is in contact with another molded resin portion adjacent to the molded resin portion in the circumferential direction in the fitted state.

2. A stator which is fitted inside a case and receives a compressive force from the case in a radially inward direction is one of a plurality of circumferentially divided stator segments, a split core, the split core being one of a plurality of split cores in a circumferential direction of a stator core, the split core having a yoke portion and teeth portions; a coil having the teeth inserted inside and disposed in a non-contact state with respect to the split core; a molded resin portion that is molded with the coil embedded therein and that receives the circumferential compressive force in the fitted state; having The mold resin portion protrudes outward in the circumferential direction beyond the yoke portion.

3. A stator which is fitted inside a case and receives a compressive force from the case in a radially inward direction is one of a plurality of circumferentially divided stator segments, a split core, the split core being one of a plurality of split cores in a circumferential direction of a stator core, the split core having a yoke portion and teeth portions; a coil having the teeth inserted inside and disposed in a non-contact state with respect to the split core; a molded resin portion that is molded with the coil embedded therein and that receives the circumferential compressive force in the fitted state; having The molded resin portion is a stator segment having an elastic member interposed between the molded resin portion and another molded resin portion adjacent to the molded resin portion in the circumferential direction in the fitted state.

4. The stator segment according to claim 3 , wherein the elastic member is attached to the molded resin portion.

5. A stator comprising a plurality of the stator segments according to any one of claims 1 to 4, the plurality of stator segments being arranged in an annular shape.

6. A stator that is fitted inside a case and receives a radially inward compressive force from the case in a fitted state, a stator core including a plurality of divided cores arranged in an annular shape, each divided core having a yoke portion and teeth portions; a plurality of coils each having a tooth portion inserted therein and arranged in a non-contact state with respect to each of the divided cores; a plurality of molded resin portions each having the coil embedded therein, which integrally join the plurality of split cores and which receive a compressive force in the circumferential direction in the fitted state; Equipped with A stator in which a gap is formed between each of the yoke portions of the plurality of split cores adjacent to each other in the circumferential direction of the stator core.

7. The stator according to claim 5 , wherein a gap is formed between each of the yoke portions of the plurality of split cores adjacent to each other in a circumferential direction of the stator core.

8. Case and The stator according to any one of claims 5 to 7, which is fitted inside the case; and a rotor having a permanent magnet and disposed inside the stator; A motor equipped with

9. The dimension of the gap in the circumferential direction is a, The radial dimension of the gap between the stator and the rotor is b, When the thickness dimension in the magnetization direction of the permanent magnet is c, The motor according to claim 8 which is configured so that the relationship a / (b+c)<0.07 is satisfied.

Images