Stator

Abstract

To provide a stator that increases possibility of securing insulation between coil wires even when a high voltage is applied to the coil wire.SOLUTION: A stator includes: an annular stator core; a plurality of teeth formed on an inner side in a radial direction of the stator core; an annular insulator covering the plurality of teeth; and a plurality of phases of coil wires wound about the plurality of teeth via the insulator. In the insulator, a first groove portion is formed that causes each of the plurality of phases of the coil wires to arrange side by side at predetermined intervals in an axial direction of the stator at an outer side in the radial direction of the insulator, and that surrounds the plurality of phases of the coil wires in a circumferential direction. The predetermined intervals are formed by providing creepage distance for securing insulation of each of the plurality of phases of the coil wires arranged in the first groove.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a stator. [Background technology]

[0002] Patent Document 1 describes a stator equipped with an insulator that electrically insulates a stator core and a stator coil. On the outer diameter side of the insulator in the stator described in Patent Document 1, three induction grooves that guide the coil wires of three phases in the circumferential direction are formed side by side in the axial direction of the stator, and the coil wires of the three phases are respectively arranged in the induction grooves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5166566 Summary of the Invention [Problem to be solved by the invention]

[0004] In the insulator in Patent Document 1, three-phase coil wires are arranged in induction grooves aligned in the axial direction of the stator, and when a high voltage is applied to the coil wires, the distance between the coil wires arranged in the induction grooves is short, and there is a risk that insulation between the coil wires cannot be ensured. In other words, the insulator in Patent Document 1 does not take into consideration the creepage distance between the coil wires according to the applied voltage.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a stator that increases the possibility of ensuring insulation between coil wires even when a high voltage is applied to the coil wires. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a stator is provided having a circular stator core, a plurality of teeth formed radially inside the stator core, a circular insulator covering the plurality of teeth, and a plurality of coil wires of multiple phases wound around the plurality of teeth via the insulator, wherein the insulator arranges the coil wires of multiple phases side by side on the radial outside of the insulator with a predetermined interval between them in the axial direction of the stator, and a first groove portion is formed in the insulator for routing the coil wires of multiple phases in the circumferential direction, and the predetermined interval is formed by providing a creepage distance to ensure insulation between the coil wires of multiple phases arranged in the first groove portion.

[0007] That is, the stator has an insulator covering the teeth, and the insulator has a first groove portion formed in which the coil wires of the multiple phases are arranged in a line at a predetermined interval in the axial direction of the stator on the radial outside, and the coil wires of the multiple phases are routed in the circumferential direction. The predetermined interval is formed by providing a creepage distance to ensure insulation between the coil wires of the multiple phases arranged in the first groove portion. In this way, by providing a creepage distance to ensure insulation between the coil wires, it is possible to increase the possibility of ensuring insulation between the coil wires, for example, even when a high voltage is applied to the coil wires. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view of a stator according to the present embodiment. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a perspective view illustrating an insulator. [Figure 4] FIG. [Diagram 5] 4A and 4B are diagrams illustrating a first groove and a second groove in a first insulator. [Figure 6] 6A and 6B are diagrams illustrating a first groove and a second groove in a second insulator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Here, an embodiment of the present invention will be described in the following order with reference to the drawings. Note that the embodiment described below is merely an example of the present invention and is not intended to limit the present invention. (1) Stator configuration: (2) Other embodiments:

[0010] (1) Stator configuration: 1 and 2 are diagrams showing the stator 1 in this embodiment, in which FIG. 1 shows a perspective view of the stator 1 and FIG. 2 shows the stator 1 viewed from above (as viewed from the upper side of the paper in FIG. 1). The stator 1 shown in FIG. 1 and FIG. 2 constitutes a motor together with a rotor (not shown) arranged on the inner diameter side of the stator 1. The motor to which the stator 1 is applied may be used as an electric motor, may be used as a generator, or may be used as a motor-generator having both a function as an electric motor and a function as a generator. For example, the stator 1 is applied to a motor of an electric vehicle or a hybrid vehicle, and the motor functions as an electric motor that generates a driving force for running and also functions as a generator that generates electricity with regenerative torque. Alternatively, the stator 1 may be applied to a water pump for a thermal management system of an electric vehicle and function as a cooling water supply device. In this specification, the direction along the axis (center axis) of the stator 1 is referred to as the "axial direction", and the direction perpendicular to the axis (the radial direction of the stator) is referred to as the "radial direction". In addition, the side of the shaft in the radial direction is referred to as the “radially inner side”, and the side opposite the shaft in the radial direction (the side away from the shaft) is referred to as the “radially outer side”. Furthermore, the direction along the circumference of a circle centered on the axis is referred to as the “circumferential direction”.

[0011] The stator 1 includes, as its main components, a stator core 10, a stator coil 20 wound around the stator core 10, and an insulator 30. The stator core 10 is a laminated steel plate configured by stacking, in the axial direction, a plurality of thin electromagnetic steel plates (e.g., silicon steel plates) formed into an annular shape by, for example, press working. Alternatively, the stator core 10 may be a dust core formed by press molding insulating coated magnetic particles.

[0012] As shown in Fig. 1, the stator core 10 has an annular yoke 11 and a plurality of teeth 12 protruding radially inward from the inner peripheral surface of the yoke 11. The teeth 12 are arranged at regular intervals in the circumferential direction on the inner peripheral surface of the yoke 11. An annular insulator 30 that covers the teeth 12 is attached to the teeth 12, and then the stator coil 20 is wound around the teeth 12. In Figs. 1 and 2, the teeth 12 are covered by the insulator 30, so the lead lines of the symbols for the teeth 12 are shown as dashed lines. Also, although there are a plurality of teeth 12 and a plurality of stator coils 20 in the circumferential direction, the lead lines of the symbols for these components are shown as one or two representatively.

[0013] As described above, the stator coil 20 is wound around the multiple teeth 12 via the insulators 30. The stator coil 20 includes multiple coil wires, a U-phase coil, a V-phase coil, and a W-phase coil. The base ends of the coil wires of each phase are connected to an input terminal (not shown), and the ends of the coil wires of each phase are connected to the ends of the coil wires of the other phases to form a neutral point. In other words, the stator coil 20 is star-connected. Note that the connection mode of the stator coil 20 may be appropriately changed depending on the specifications of the motor, etc. For example, the stator coil 20 may be delta-connected instead of star-connected.

[0014] The insulator 30 is a member for ensuring insulation between the stator core 10 and the stator coil 20 and for protecting the stator core 10. The insulator 30 is made of a thermoplastic resin such as PPS resin, and is formed by injection molding. Note that the material of the insulator 30 is not limited to this, but it is preferable to use a material that is heat resistant and has high insulating properties.

[0015] 3 to 6 are diagrams for explaining the insulator 30 in this embodiment, in which FIG. 3 shows a perspective view of the insulator 30, and FIG. 4 shows a view of the insulator 30 viewed from above. Also, FIG. 5 and FIG. 6 are diagrams for explaining the groove portion 31 formed in the insulator 30, and show a front view of the stator 1 including the insulator 30 and an enlarged view of a part surrounded by a dashed line in the front view. The insulator 30 is formed in an annular shape so as to cover the teeth 12. Therefore, as shown in FIG. 4, when the insulator 30 is viewed from the axial direction (from above), it has a shape substantially similar to the shape of the stator 1 shown in FIG. 2 except for the stator coil 20. That is, the insulator 30 includes an annular portion 32 and teeth 33 protruding radially inward from the annular portion 32. Furthermore, flange portions 34 are formed at the tips (radially inner ends) of the teeth 33 of the insulator 30 to prevent the stator coil 20 wound around the teeth 33 from moving radially inward and falling off the teeth 33. Note that in Figures 3 and 4, there are multiple teeth 33 and flange portions 34 formed on the teeth 33 in the circumferential direction, but the reference numerals for these components are drawn to only two representative ones.

[0016] Further, the insulator 30 is configured to cover the teeth 12 from both sides in the axial direction so that the stator core 10 including the teeth 12 is not exposed in the axial direction (in other words, to protect the stator core 10). As described above, the stator core 10 is made of a plurality of thin electromagnetic steel plates, and therefore may be easily deteriorated if the stator coil 20 is wound directly around the exposed portion of the stator core 10. Therefore, in order to prevent the stator core 10 including the teeth 12 from being exposed in the axial direction, in addition to insulation from the stator coil 20, the insulator 30 is configured to cover the teeth 12 from both sides in the axial direction (top and bottom of the paper in FIG. 1). That is, the insulator 30 includes a first insulator 30a that covers the stator coil 20 from one side in the axial direction (for example, the upper side of the paper in the front views of FIG. 1, 5, and 6) and a second insulator 30b that covers the stator coil 20 from the other side in the axial direction (for example, the lower side of the paper in the front views of FIG. 1, 5, and 6). In the following description, when there is no need to distinguish between the "first" and the "second", the alphabetic subscript will be omitted and the term will simply be referred to as the "insulator 30".

[0017] The insulator 30 has grooves 31 formed on its radially outer side to arrange the coil wires of multiple phases (i.e., U-phase, V-phase, and W-phase coil wires) in the axial direction and to route the coil wires of multiple phases in the circumferential direction. Specifically, as shown in Figs. 3, 5, and 6, on the radially outer side of the insulator 30, a plurality of grooves recessed radially inward are formed in the circumferential direction (i.e., the outer periphery), and the plurality of grooves are arranged in the axial direction. In this embodiment, four grooves are formed on the outer periphery of the first insulator 30a shown in the upper part of the drawing, and two grooves are formed on the outer periphery of the second insulator 30b shown in the lower part of the drawing. As shown in the enlarged views of Figs. 5 and 6, the plurality of grooves include two types of grooves having different widths at least in the axial direction, and in this embodiment, the groove with a relatively large groove width is defined as the "first groove portion 31a" and the groove with a relatively small groove width is defined as the "second groove portion 31b".

[0018] In this embodiment, as shown in Fig. 5, two first grooves 31a and two second grooves 31b are formed in the first insulator 30a. Also, as shown in Fig. 6, one first groove 31a and one second groove 31b are formed in the second insulator 30b. Note that the number of grooves formed in the first insulator 30a and the number of grooves formed in the second insulator 30b may be in an inverse relationship (i.e., two grooves are formed in the first insulator 30a and four grooves are formed in the second insulator 30b), but it is preferable that the number of grooves formed in the second insulator 30b is two as in this embodiment (in other words, it is preferable that the number of grooves formed in the first insulator 30a is four). In this embodiment, a terminal unit including a terminal (both not shown) is provided on the second insulator 30b side, and in that case, for example, the axial length from the stator core 10 to the second insulator 30b side may be longer than the axial length to the first insulator 30a side. In other words, this is to balance the axial length to the first insulator 30a side and the axial length to the second insulator 30b side with the stator core 10 as the base point.

[0019] In each of the first grooves 31a, one of the coil wires of the multiple phases is arranged, and the first grooves 31a are formed with a predetermined interval in the axial direction. This predetermined interval is formed by providing a creepage distance to ensure insulation between the coil wires of the multiple phases arranged in the first grooves 31a. In other words, each coil wire is arranged in the first grooves 31a with a predetermined interval in the axial direction. The creepage distance is the shortest distance along the surface of the insulating material between two conductive parts. That is, in this embodiment, the creepage distance is the shortest distance that does not cause a short circuit between the coil wires when measured along the surface (outer diameter) of the insulator 30. Since the creepage distance is the shortest distance along the surface of the insulator as described above, it is not limited to the shortest distance based on the linear distance between the coil wires of the multiple phases, but may be the shortest distance along the grooves or protrusions formed in the insulator 30. In this embodiment, the creepage distance is ensured in the axial direction by forming the second grooves 31b between the coil wires of the multiple phases arranged in the first grooves 31a. In other words, the creepage distance is ensured in the axial direction by forming the second grooves 31b between the conductive parts. By forming the second grooves 31b in this way, it is possible to shorten the axial length of the stator 1 compared to a case in which the creepage distance is ensured by the linear distance without forming the second grooves 31b.

[0020] Here, the reason for providing the creepage distance in this embodiment will be described in more detail. As described above, the creepage distance is provided to prevent the coil wires from shorting each other. The stator 1 in this embodiment forms a motor together with a rotor (not shown), and the motor is used as a driving force source for driving a vehicle, for example, in an electric vehicle or the like. In order to generate driving force for driving by the motor, a high output of the motor is required, and in such a case, a high voltage (for example, about 800V) is applied to the stator coil. On the other hand, when multiple phase coil wires are simply arranged in the grooves in the axial direction, as in the configuration described in the above-mentioned Patent Document 1, there is a risk that insulation between the coil wires cannot be ensured when a high voltage is applied to the stator coil. Therefore, in this embodiment, a creepage distance is provided between the first grooves 31a in which the multiple phase coil wires are arranged, so that insulation between the multiple phase coil wires is ensured even when a high voltage is applied to the stator coil 20.

[0021] The creepage distance is determined based on the effective value of the voltage used, the pollution level based on the usage environment, and the material group (the material of the insulator in this embodiment), as defined in the JIS standard. For example, the higher the voltage used, i.e., the voltage applied to the coil wires of multiple phases, the longer the creepage distance. This is because, as the voltage applied to the coil wires increases, the distance over which electricity flows increases, and therefore it is necessary to lengthen the creepage distance to ensure insulation. Also, the higher the pollution level, the longer the creepage distance. This is because the higher the pollution level, the more likely it is that contaminants such as dust will adhere to the coil wire, which may result in a decrease in insulation performance. In addition, tracking resistance, which indicates resistance to tracking such as short circuits, may be taken into consideration when determining the creepage distance.

[0022] 5 and 6, the first groove portion 31a and the second groove portion 31b in the insulator 30 are alternately formed in the axial direction. More specifically, the first groove portion 31a and the second groove portion 31b are located on the outer side of the stator core 10 in the axial direction when viewed from the end face 10a of the stator core 10 (i.e., the outermost surface of the stator core 10 in the axial direction), and the second groove portion 31b and the first groove portion 31a are formed in this order toward the outer side. That is, in the axial direction, the grooves are formed in the order of the second groove portion 31b and the first groove portion 31a from the end face 10a of the stator core 10 as a base point toward the outer side. In other words, the second groove portion 31b in which the coil wire is not arranged is formed on the side close to the end face 10a of the stator core 10, and the first groove portion 31a is formed on the outer side in the axial direction via the second groove portion 31b. In this manner, by arranging the second groove portion 31b on the side closer to the end face 10a of the stator core 10, insulation between the coil wires of the multiple phases is ensured, and also insulation from the stator core 10 is ensured. In particular, since two coil wires (e.g., U-phase and V-phase coil wires) are arranged in the first insulator 30a, grooves are formed from the end face 10a of the stator core 10 in the order of the second groove portion 31b, the first groove portion 31a, the second groove portion 31b, and the first groove portion 31a, i.e., the second groove portion 31b is formed between the coil wires of the multiple phases arranged in the first groove portion 31a.

[0023] Since the coil wires are arranged in the first groove 31a, the first groove 31a has a width (width in the axial direction) that allows the coil wires to enter the groove, but since the second groove 31b is a groove for ensuring the creepage distance, it is preferable that the configuration prevents the coil wires from entering. Therefore, in this embodiment, the width of the second groove 31b in the axial direction is a width that prevents the coil wires from entering. In other words, the width of the second groove 31b in the axial direction is smaller than that of the first groove 31a.

[0024] Next, the effects of this embodiment will be described. As described above, in this embodiment, the stator 1 has the insulator 30 that covers the teeth 12. The insulator 30 has a first groove portion 31a formed therein for arranging the coil wires of the multiple phases in the axial direction of the stator 1 at a predetermined interval on the radial outside and routing the multiple coil wires in the circumferential direction. The predetermined interval is formed by providing a creepage distance for ensuring insulation between the coil wires of the multiple phases arranged in the first groove portion 31a. In this way, by providing a creepage distance for ensuring insulation between the coil wires of the multiple phases, it is possible to increase the possibility of ensuring insulation between the coil wires, for example, even when a high voltage is applied to the coil wires.

[0025] In this embodiment, the creepage distance is ensured in the axial direction by forming the second grooves 31b between the coil wires of the multiple phases arranged in the first grooves 31a. The creepage distance is ensured by the distance along the surface (outer diameter) of the groove formed between the coil wires. This makes it possible to prevent the size of the stator 1 from becoming larger in the axial direction compared to, for example, a case in which no grooves (second grooves 31b) are formed between the coil wires of the multiple phases and the insulation distance between the coil wires of the multiple phases is ensured by the linear distance. In other words, the axial length of the stator 1 can be shortened.

[0026] In this embodiment, the first groove portion 31a and the second groove portion 31b are located on the outside of the stator core 10 in the axial direction when viewed from the end face 10a of the stator core 10, and the second groove portion 31b and the first groove portion 31a are formed in this order toward the outside. That is, the second groove portion 31b is formed on the side of the groove portion relatively closer to the stator core 10, and the first groove portion 31a is formed on the side relatively farther from the stator core 10. As a result, the second groove portion 31b, in which no coil wire is arranged, is located between the coil wire arranged in the first groove portion 31a, which is a conductive portion, and the stator core 10, which is a conductive portion. The insulator 30 is a member that ensures insulation between the stator coil 20 and the stator core 10, and by setting the positional relationship between the first groove portion 31a and the second groove portion 31b as described above, it is possible to further ensure insulation between the stator core 10 and the stator coil 20. In other words, the insulator 30 in this embodiment can better ensure insulation between the stator core 10 and the stator coil 20 while ensuring insulation between the coil wires of multiple phases.

[0027] In this embodiment, the second groove 31b has a smaller axial width than the first groove 31a. That is, the second groove 31b is a groove for ensuring the creepage distance as described above, and therefore the coil wire is not disposed therein. Therefore, the axial width of the second groove 31b is smaller than the axial width of the first groove 31a in which the coil wire is disposed, and the width is set to, for example, a width that does not allow the coil wire to enter. This makes it possible to prevent the coil wire from entering the second groove 31b, and as a result, it is possible to further increase the possibility of ensuring insulation between the coil wires of multiple phases.

[0028] Furthermore, in this embodiment, the above-mentioned creepage distance is made longer as the voltage applied to the coil wires of the multiple phases increases. This is because, as the voltage applied to the coil wires increases, the distance over which electricity flows increases, increasing the possibility of the coil wires of the multiple phases shorting each other. As a result, even if the applied voltage is increased, the creepage distance increases according to the applied voltage, thereby increasing the possibility of ensuring insulation between the coil wires of the multiple phases.

[0029] (2) Other embodiments: The above embodiment is an example for carrying out the present invention, and is not limited thereto, and various other embodiments can be adopted. In the above embodiment, the creepage distance is configured to be ensured by forming the second groove portion 31b, but the means for ensuring the creepage distance is not limited thereto as long as the insulation between the coil wires of the multiple phases can be ensured. For example, the creepage distance may be ensured by forming a protrusion or a convex portion between the conductive parts (i.e., between the coil wires or between the coil wire and the end surface 10a of the stator core 10). In addition, depending on the constraints such as the space in which the stator 1 is mounted, the axial length of the stator 1 may be long in some cases. In such a case, the insulation may be ensured simply by the linear distance (spatial distance) between the coil wires of the multiple phases without forming a groove portion, a convex portion, a protrusion, or the like.

[0030] In the above-described embodiment, the creepage distance has been described as the shortest distance for ensuring insulation between the coil wires of the multiple phases. This is because the axial length of the stator 1 can be shortened by adopting the shortest distance. On the other hand, as described above, depending on constraints such as the space in which the stator 1 is mounted, the axial length of the stator 1 may be allowed to be long. In such a case, the creepage distance is not limited to the shortest distance for ensuring insulation between the coil wires of the multiple phases, and may be longer than the shortest distance. In other words, the shortest distance is the minimum value of the creepage distance, and the creepage distance may be at least equal to or greater than the minimum value. [Explanation of symbols]

[0031] 1...stator, 10...stator core, 10a...end face (of stator core), 11...yoke, 12...teeth, 20...stator coil (multiple-phase coil wire), 30...insulator, 30a...first insulator, 30a...second insulator, 31...groove portion, 31a...first groove portion, 31b...second groove portion, 32...annular portion, 33...teeth (in insulator), 34...flange portion.

Claims

1. An annular stator core; A plurality of teeth formed on a radially inner side of the stator core; an annular insulator covering the teeth; A coil wire of a plurality of phases is wound around the plurality of teeth via the insulator; A stator having The insulator is provided with a first groove portion for arranging the coil wires of the multiple phases in a circumferential direction of the stator at predetermined intervals on a radially outer side of the insulator, and for routing the coil wires of the multiple phases in a circumferential direction, the predetermined interval is formed by providing a creepage distance for ensuring insulation between the coil wires of the multiple phases arranged in the first groove portion. Stator.

2. The creepage distance is ensured by forming second grooves between the coil wires of the multiple phases arranged in the first grooves in the axial direction. The stator according to claim 1 .

3. The first groove portion and the second groove portion are In the axial direction, the second groove portion and the first groove portion are located on the outer side of the stator core as viewed from an end face of the stator core, and the second groove portion and the first groove portion are formed in this order toward the outer side. The stator according to claim 2 .

4. The second groove portion has a width in the axial direction smaller than that of the first groove portion.

4. A stator according to claim 2 or 3.

5. The creepage distance becomes longer as the voltage applied to the coil wires of the multiple phases increases. The stator according to claim 1 .

Images