JP7582556B1 - Rotating Electric Machine - Google Patents

Abstract

The rotating electric machine (1) includes a rotor (20) and a stator coil (11) fixed to a shaft (50) supported rotatably in a housing, and a stator (10) having a coil base (12) fixed to the housing. The stator coil (11) is pressed against the coil base (12) and fixed by a coil holding member (40) engaged with the stator coil (11) and a fixing target part different from the coil base (12).

Description

The present disclosure relates to a rotating electric machine in which stator coils can be fixed easily and inexpensively.

Rotating electric machines often have coils through which current flows. In particular, when a stator coil is provided on the stator side, it is necessary to fix the stator coil in some way so that it does not move inside the rotating electric machine. For example, Patent Document 1 proposes a method of fixing the stator coil by winding the stator coil around an iron core, then sealing both sides in the axial direction, arranging multiple coils in a ring shape, and molding it with resin.

Special Publication No. 2013-537797

However, conventional methods require a resin molding process, which increases costs. In addition, there is a problem that the molding resin deteriorates with an increase in environmental temperature, reducing the fixing strength of the stator coil.

The present disclosure has been made to solve the problems described above, and provides a rotating electric machine in which the stator coil is fixed using a simple process to suppress increases in costs, and the stator coil is mechanically fixed so that the fixing strength of the stator coil is maintained even when the environmental temperature rises.

The rotating electric machine according to the present disclosure includes a rotor fixed to a shaft rotatably supported by a housing, and a stator having a stator coil and a coil base fixed to the housing. The stator coil is pressed and fixed to the coil base by a tensile force of a coil holding member engaged with a fixing target part different from the stator coil and the coil base.

A rotating electric machine according to the present disclosure includes a rotor fixed to a shaft rotatably supported by a housing, and a stator having a stator coil and a coil base fixed to the housing. The number of rotors is greater than the number of stators, and the rotors are arranged on both sides of the stator in the magnetic gap direction in which the rotors and the stators face each other. The stator coil has a first stator coil and a second stator coil different from the first stator coil. The first stator coil and the second stator coil are respectively arranged on both sides of the coil base in the magnetic gap direction. The stator coil is pressed and fixed against the coil base by a coil holding member engaged with the first stator coil and a fixing target portion including the second stator coil different from the coil base.

1 is a schematic development view of a rotating electric machine according to a first embodiment; FIG. 2 is a diagram showing an example of a stator coil. 1 is a schematic cross-sectional view of a rotating electric machine according to a first embodiment; FIG. 4 is a partially enlarged view of FIG. 3 . 4 is an enlarged view of a portion where the stator coil is fixed to the coil base. FIG. 5 is a schematic cross-sectional view of a stator coil having another shape according to the first embodiment. FIG. FIG. 2 is a diagram showing an example of a coil base according to the first embodiment. FIG. 8 is a diagram showing a stator coil disposed on the coil base of FIG. 7 . FIG. 11 is a diagram showing another example of the coil base in the first embodiment. FIG. 10 is a diagram showing a stator coil disposed on the coil base of FIG. 9 . FIG. 13 is a diagram showing a case where a communication portion is provided in a coil base. FIG. 12 is a diagram showing a stator coil disposed on the coil base of FIG. 11 . 13A to 13C are diagrams showing another method of fixing the stator coil to the coil base. FIG. 14 is a partially enlarged view of FIG. 13 . FIG. 11 is a schematic development view of a rotating electric machine according to a second embodiment. FIG. 11 is a schematic development view of an example of a rotating electric machine according to a second embodiment. FIG. 11 is a schematic cross-sectional view of an example of a rotating electric machine according to a second embodiment. FIG. 18 is a partially enlarged view of FIG. 11 is a schematic cross-sectional view of another stator coil shape according to the second embodiment. FIG. 13A to 13C are diagrams showing an example of a method for engaging a coil holding member according to the second embodiment; FIG. 11 is a diagram showing an example of a stator coil according to a second embodiment; 13A and 13B are diagrams showing an example of a coil holding member according to a second embodiment; 13A and 13B are diagrams showing an example of a coil holding member according to a second embodiment; 13A and 13B are diagrams showing an example of the shape of a coil base according to the second embodiment; FIG. 25 is a diagram showing a stator coil fixed to the coil base of FIG. 24. FIG. 26 is an enlarged view of a coil holding member engagement portion in FIG. 25 . FIG. 11 is a schematic development view of a rotating electric machine according to another embodiment.

Embodiment 1.
Hereinafter, a rotating electric machine according to an embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic development view of a rotating electric machine according to the first embodiment. In this embodiment, an axial gap type rotating electric machine in which the direction of the magnetic gap is parallel to a rotating shaft 51 will be used for the description. Note that structural components are not shown in Fig. 1. The rotating electric machine has a rotor 20 and a stator 10.

The rotor 20 has a back yoke 21 and permanent magnets 22 fixed to the back yoke 21. The back yoke 21 is made of magnetic material and is formed in a hollow disk shape. Multiple permanent magnets 22 are used in the form of segments. The multiple permanent magnets 22 are arranged at an equiangular pitch in the circumferential direction in the radial middle part of the back yoke 21.

The permanent magnets 22 are formed in a sector shape. Each permanent magnet 22 is magnetized in the axial direction so that the axial end face is a north pole or a south pole. When viewed from the axial direction, the permanent magnets 22 are arranged so that the north pole and the south pole are alternately arranged in the circumferential direction. Note that the permanent magnets 22 are not limited to segment-shaped magnets, and may be formed as a single hollow disk. In this case, the permanent magnets 22 are magnetized so that the north pole and the south pole appear alternately in the circumferential direction. Also, any number of permanent magnets 22 formed with multiple poles may be used.

The stator 10 has a multi-phase stator coil 11 and a coil base 12. FIG. 2 shows an example of the multi-phase stator coil 11. One of the multiple windings is highlighted. The stator coil 11 has multiple windings for each phase, which are distributed windings that overlap each other in the circumferential direction. The stator coil 11 may be concentrated windings in which the windings do not overlap each other. The winding has a pair of sides 111 that are approximately fan-shaped and perpendicular to the rotation direction dr of the rotor 20. The pair of sides 111 are connected by an outer diameter side coil end portion 112 and an inner diameter side coil end portion 113. If the radial length of the sides 111 is approximately equal to the radial length of the permanent magnet 22 that is approximately fan-shaped, the magnetic flux generated from the permanent magnet 22 can be effectively used. The stator coil 11 is positioned and fixed on the coil base 12 that is formed in an approximately hollow disk shape. A method for fixing the stator coil 11 to the coil base 12 will be described later.

The structure of the rotating electric machine 1 of the present disclosure will be described with reference to FIG. 3. FIG. 3 is a schematic cross-sectional view of the rotating electric machine 1 of the present disclosure. The housing of the rotating electric machine 1 includes a frame 30, a bracket 31, and a bracket 32. The rotor 20 and the stator 10 are arranged to face each other in the axial direction in a substantially disk-like shape. The rotor 20 is fixed to the shaft 50. The shaft 50 is supported rotatably by the brackets 31 and 32, which have a bearing holding portion in the center, via a bearing 52. The brackets 31 and 32 are formed in a substantially hollow disk shape from a non-magnetic material such as aluminum. The shaft 50 may be formed from a magnetic material or a non-magnetic material. The coil base 12 is fixed to the bracket 32. The coil base 12 may be fixed to a frame 30 formed in a cylindrical shape from a non-magnetic material such as aluminum.

The flow of magnetic flux within the rotating electric machine 1 according to the present disclosure will be described. The magnetic flux coming out of the permanent magnet 22 with the N pole on the magnetic gap side of the rotor 20 interlinks with the stator coil 11, passes through the coil base 12, interlinks with the stator coil 11 again, and enters the permanent magnet 22 with the S pole on the magnetic gap side of the rotor 20. The magnetic flux coming out of the permanent magnet 22 with the N pole on the back yoke 21 side passes through the back yoke 21 and enters the permanent magnet 22 with the S pole on the back yoke 21 side. The magnetic flux makes one revolution within the rotating electric machine 1, forming a magnetic circuit. In the radial gap type, the magnetic flux flows two-dimensionally within the same plane, but the rotating electric machine 1 according to the present disclosure is different in that the magnetic flux flows three-dimensionally.

The torque generation principle of the rotating electric machine 1 disclosed herein is the same as that of the radial gap type, and current is passed through the stator coil 11 in synchronization with the magnetic pole position of the rotor 20. When current is passed through the stator coil 11, copper loss occurs in the stator coil 11. In general, the increase in stator coil temperature due to copper loss determines the maximum value of the current passed through the stator coil 11.

The coil base 12 may be, for example, a wound core formed by concentrically winding a thin magnetic plate such as an electromagnetic steel sheet, or a pressed powder core formed by pressing insulatingly coated soft magnetic iron powder. The coil base 12 may also be formed of a non-magnetic material such as resin. If the coil base 12 is formed of a magnetic material, the magnetic resistance of the magnetic circuit in the rotating electric machine 1 decreases, and the torque increases.

3, 4 and 5, a method of fixing the stator coil 11 will be described. FIG. 4 is a diagram showing an example of a method of engaging the coil holding member 40. FIG. 5 is a partially enlarged view of FIG. 4. The rotating electric machine 1 according to the present disclosure further includes a coil holding member 40 for fixing the stator coil 11. After the stator coil 11 is positioned and temporarily fixed on the coil base 12, the coil base 12 is fixed to the bracket 32. Then, one end of a wire-like coil holding member 40 such as a wire or a piano wire is engaged with the stator coil 11 as shown in FIG. 4. Then, the other end of the coil holding member 40 is engaged with a fixing target part different from the coil base 12, such as the frame 30 or a housing including the bracket 32, by a method such as welding. The wire-like coil holding member 40 may be a racing material or a string-like member made of resin.

At this time, as shown in Figure 5, the coil holding member 40 is engaged with the engagement portion of the coil holding member 40 of the stator coil 11 such that a tensile force Ft acts on the engagement portion of the coil holding member 40. This tensile force Ft causes a pressing force Fc to act on the stator coil 11 in a direction toward the coil base 12, and the stator coil 11 is fixed to the coil base 12. In the example of Figure 3, one end of the coil holding member 40 engaged with the outer diameter side coil end portion 112 of the stator coil 11 is engaged with the frame 30 at the other end, and the fixed object is the frame 30. Also, one end of the coil holding member 40 engaged with the inner diameter side coil end portion 113 of the stator coil 11 is engaged with the bracket 32, and the fixed object is the bracket 32.

The stator coil 11 is fixed to the coil base 12 by a pressing force Fc in the direction toward the coil base 12, so that the stator coil 11 is mechanically fixed to the coil base 12 without using adhesive or molded resin. This eliminates the need for complex processes such as adhesive coating and molding, and can suppress increases in costs. In addition, when adhesive or molded resin is used to fix the stator coil 11, the fixing strength of the stator coil 11 decreases in a high-temperature environment due to a decrease in the adhesive strength of the adhesive and thermal deterioration of the molded resin. On the other hand, in the present disclosure, the stator coil 11 is mechanically fixed to the coil base 12 using the coil holding member 40, so that the fixing strength is maintained even in a high-temperature environment.

The coil holding member 40 may be engaged with the outer diameter side coil end portion 112 of the stator coil 11 and a fixing target portion other than the coil base 12, such as the frame 30 or bracket 32, to fix the stator coil 11 to the coil base 12. In this case, since space is secured on the inner diameter side, the diameter of the shaft 50 becomes larger and the rigidity of the shaft 50 becomes higher.

The coil holding member 40 may be engaged with the inner diameter side coil end portion 113 of the stator coil 11 and a fixing target portion other than the coil base 12, such as a bracket 32, to fix the stator coil 11 to the coil base 12. In this case, a structure for engaging the coil holding member 40 is not required on the outer diameter side, so that the outer diameter of the rotating electric machine 1 can be prevented from becoming large.

The stator coil 11 may be fixed to the coil base 12 by engaging multiple coil holding members 40 at an equal angular pitch in the circumferential direction with the stator coil 11 and a fixing target part other than the coil base 12, such as the frame 30 or bracket 32. By fixing the stator coil 11 to the coil base 12 with multiple coil holding members 40, the force that the stator coil 11 receives from the coil holding members 40 is dispersed. This makes it possible to prevent excessive stress from being applied to some parts of the stator coil 11. It is also preferable to fix the stator coil 11 by engaging the coil holding members 40 in order on a diagonal line. This improves the accuracy of the parallelism of the opposing surface of the stator 10 with the rotor 20.

3, the coil base 12 is fixed to the bracket 32, but may be fixed to the frame 30. Also, one end of the coil holding member 40 engaged with the outer diameter side coil end portion 112 is engaged with the frame 30 at the other end, but may be engaged with the bracket 32 in the same manner as the coil holding member 40 engaged with the inner diameter side coil end portion 113 at one end. Also, in the example of FIG. 3, the coil holding member 40 is engaged with the outer diameter side coil end portion 112 and the inner diameter side coil end portion 113, but the engagement points of the coil holding member 40 to the stator coil 11 are not limited to the outer diameter side and inner diameter side coil end portions 112, 113, and may be engaged with a pair of sides 111.

Although the pressing force Fc acting on the stator coil 11 has been described as being generated by the tensile force Ft from the coil holding member 40, the pressing force Fc may also be generated by elastic deformation of either the outer diameter side or inner diameter side coil end portions 112, 113 of the stator coil 11. In addition, the coil holding member 40 may have elasticity, and when the coil holding member 40 engages with the stator coil 11 and a fixed target portion other than the coil base 12, tensile stress may be generated at both ends of the coil holding member 40, and the pressing force Fc may be generated by this tensile stress. The pressing force Fc may also be generated by the above combinations.

6 is a diagram showing the outer diameter side and inner diameter side coil end portions 112, 113 formed by bending them toward the coil base 12. As shown in FIG. 6, the outer diameter side and inner diameter side coil end portions 112, 113 are formed by bending them toward the coil base 12, and the coil holding member 40 is engaged with the formed portions. This makes it possible to prevent the coil holding member 40 from protruding toward the rotor 20 side beyond the magnetic gap side end face of the stator coil 11. The portions that are formed by bending them toward the coil base 12 are not limited to the outer diameter side and inner diameter side coil end portions 112, 113, but may be a pair of sides 111.

The coil holding member 40 may be formed of a material with a high thermal conductivity. Heat transferred from the stator coil 11 to the coil holding member 40 is transferred to the frame 30 and the bracket 32. The heat is also dissipated from the surface of the coil holding member 40. This suppresses the temperature rise of the stator coil 11.

Figure 7 is a diagram showing an example of a coil base 12a in this embodiment. The coil base 12a has a protruding rib 14 that protrudes in the direction of the magnetic gap on the surface facing the magnetic gap and on which the stator coil 11 is arranged. Figure 8 is a diagram showing the stator coil 11 arranged on the coil base 12a on which the protruding rib 14 is provided. A pair of sides 111 abut against the rib 14. This determines the circumferential position of the stator coil 11. In the example of Figure 7, the protruding rib 14 is provided so as to correspond to a pair of sides 111 perpendicular to the rotation direction dr of all of the rotors 20, but it is not necessary that they correspond to all of the sides 111.

Figure 9 is a diagram showing another example of the coil base 12b of this embodiment. The ribs 14a provided on the coil base 12b extend in a direction perpendicular to the rotation direction dr of the rotor 20. In the example of this embodiment, this corresponds to the radial direction. The ribs 14a are provided at an equal angular pitch in the circumferential direction, and two adjacent ribs 14a form a slot 15. The ribs 14a are provided so that the slots 15 correspond to all sides 111 of the stator coil that are perpendicular to the rotation direction dr of the rotor 20. The radial length of the ribs 14a should be approximately the same as the sides 111 of the stator coil. Figure 10 is a diagram showing the case where the stator coil 11 is arranged on the coil base 12b of Figure 9. In this case, the sides 111 of the stator coil 11 are inserted along the slots 15, making it possible to assemble the stator coil using an automatic winding machine.

Figure 11 is a diagram showing a case where a communication portion 13 is provided on the coil base 12c. Figure 12 is a diagram showing a stator coil 11 arranged on this coil base 12c. As shown in Figure 11, the coil base 12c is provided with a communication portion 13, and the coil holding member 40 is engaged with the stator coil 11 and a fixing target portion other than the coil base 12c through the communication portion 13. This makes it possible to fix the stator coil 11 to the coil base 12c using the coil holding member 40 even when the outer diameter of the coil base 12c is larger than the outer diameter of the stator coil 11, or when the inner diameter of the coil base 12c is smaller than the inner diameter of the stator coil 11. In addition, since the coil base 12c can be made larger, space for fixing to the bracket 32 is secured.

Figure 13 is a diagram showing another method of fixing the stator coil 11 to the coil base 12. Figure 14 is a partially enlarged view of Figure 13. One end of the coil holding member 40 is engaged with, for example, the outer diameter side coil end portion 112 of the stator coil 11. The other end of the coil holding member 40 is passed through the opposite side of the magnetic gap of the coil base 12 and engaged with the inner diameter side coil end portion 113 of the stator coil 11. In this case, the inner diameter side coil end portion 113 corresponds to the fixed target portion. As shown in Figure 14, tension Ft acts on the coil holding member 40 at the engagement portion with the outer diameter side coil end portion 112 of the stator coil 11 and the abutment portion with the coil base 12. This tension Ft causes a pressing force Fc in the direction toward the coil base 12 to act on the stator coil 11, and the stator coil 11 is fixed to the coil base 12.

In this case, a radial slot 15 may be provided on the surface of the coil base 12 opposite the magnetic gap. As a result, by arranging the coil holding member 40 in this slot 15, the coil base 12 can be fixed to the bracket 32 without the coil holding member 40 interfering with the bracket 32. According to this method of fixing the stator coil 11, the stator coil 11 can be mechanically fixed to the coil base 12 before the coil base 12 is fixed to the bracket 32, improving the reliability of the assembly process.

In the example of Figure 13, the coil holding member 40 is engaged with the outer diameter side coil end portion 112 and the inner diameter side coil end portion 113 of the stator coil, but both ends may be engaged with the outer diameter side coil end portion 112 of the stator coil 11 as long as they do not interfere with the central portion. In this case, when attaching the coil holding member 40 to the stator coil 11, there is space on the outer diameter side, improving the workability of the attachment work.

<Effects of First Embodiment>
In the rotating electric machine according to the first embodiment, the coil holding member 40 is engaged with the stator coil 11 and a fixing target portion different from the coil base 12. As a result, a pressing force Fc is generated in the stator coil 11 in a direction toward the coil base 12, and the stator coil 11 is mechanically fixed to the coil base 12.

With this configuration, the stator coil 11 is mechanically fixed to the coil base 12. This eliminates the need for processes such as resin molding and adhesives, and allows the stator coil 11 to be fixed in place through a simple process. Furthermore, the fixing strength of the stator coil 11 is maintained even in high-temperature environments.

The coil holding member 40 may be engaged with only one of the outer diameter side coil end portion 112 or the inner diameter side coil end portion 113 of the stator coil 11. When the coil holding member 40 is engaged with only the outer diameter side coil end portion 112, space in the inner diameter portion can be secured. The outer diameter of the shaft 50 becomes larger, and the rigidity of the shaft 50 becomes higher.

When the coil holding member 40 is engaged only with the inner diameter side coil end portion 113, a structure for engaging the coil holding member 40 is not required on the outer diameter side. This prevents the outer diameter of the rotating electric machine 1 from becoming large.

The coil holding member 40 may also be engaged with both the outer diameter side coil end portion 112 and the inner diameter side coil end portion 113 of the stator coil 11. With this configuration, the number of fixing points by the coil holding member 40 increases, thereby increasing the fixing strength of the stator coil 11.

The coil holding members 40 may also be engaged at multiple locations in the circumferential direction. This configuration distributes the stress acting on the stator coil 11. Also, by engaging the coil holding members 40 in order on the diagonal line, the accuracy of the parallelism of the magnetic gap surface of the stator coil 11 is improved.

The coil holding member 40 may also be formed in a wire shape. With this configuration, the stator coil 11 is mechanically fixed.

In addition, the portion of the stator coil 11 where the coil holding member 40 engages may be bent toward the coil base 12. With this configuration, the coil holding member 40 does not protrude toward the magnetic gap side.

In addition, the thermal conductivity of the coil holding member 40 is high. With this configuration, the heat of the stator coil 11 is transferred to the coil holding member 40 and dissipated from the coil holding member 40. This suppresses the temperature rise of the stator coil 11.

In addition, a communication portion 13 is provided in the coil base 12a, and the coil holding member 40 connects the stator coil 11 to a fixed target portion different from the coil base 12a through the communication portion 13. With this configuration, even if the coil base 12a is larger than the stator coil 11, the stator coil 11 is mechanically fixed using the coil holding member 40.

In addition, a number of protruding ribs 14 protruding in the direction of the magnetic gap are provided on the surface of the coil base 12b facing the magnetic gap and on which the stator coil 11 is disposed. With this configuration, the edge 111 of the stator coil 11 perpendicular to the rotation direction dr of the rotor 20 abuts against the side of the rib 14 and is fixed. This determines the circumferential position of the stator coil 11.

The ribs 14a extend in a direction perpendicular to the rotation direction dr of the rotor 20. The ribs 14a correspond to all the sides 111 of the stator coil 11 perpendicular to the rotation direction dr of the rotor 20, and slots 15 are formed between adjacent ribs 14a. The sides 111 of the stator coil 11 perpendicular to the rotation direction dr of the rotor 20 are inserted into the slots 15. With this configuration, the sides 111 of the stator coil 11 abut against the side surfaces of the ribs 14a and are fixed, thereby determining the circumferential position of the stator coil 11. Furthermore, since the stator coil 11 is assembled along the ribs 14a, assembly using an automatic winding machine is possible.

In addition, in the rotating electric machine according to embodiment 1, the magnetic gap direction of the rotating electric machine 1 is parallel to the rotating shaft 51 of the rotating electric machine 1. With this configuration, the magnetic gap surface is increased in the flat structure, and the torque is increased.

Embodiment 2.
The rotating electric machine 1 according to the second embodiment will be described below with reference to the drawings, focusing on the differences from the rotating electric machine 1 according to the first embodiment. FIG. 15 is a schematic development view of the rotating electric machine according to the second embodiment. The rotors 20 are arranged on both sides of the stator 10 in the magnetic gap direction. The basic structures of the stator 10 and the rotor 20 are the same as those of the first embodiment. One rotor 20 is the first rotor 23, and the other rotor 20 is the second rotor 24. The first rotor 23 and the second rotor 24 are fixed to a common shaft 50 (not shown) and rotate. The circumferential phases of the permanent magnets 22 of the first rotor 23 and the second rotor 24 are equal to each other. The permanent magnets 22 of the first rotor 23 and the permanent magnets 22 of the second rotor 24, which are arranged in the same circumferential phase, are magnetized to different polarities. The sum of the torque generated in the first rotor 23 and the torque generated in the second rotor 24 is the output torque from the shaft 50. In order to reduce the time fluctuation of the output torque, the permanent magnets 22 of the first rotor 23 and the permanent magnets 22 of the second rotor 24 may have different circumferential phases.

The magnetic circuit of the rotating electric machine according to the second embodiment will be described. The magnetic flux coming out of the permanent magnet 22 of the first rotor 23, whose magnetic gap side is magnetized to the N pole, interlinks with the stator coil 11 and enters the permanent magnet 22 of the second rotor 24, whose magnetic gap side is magnetized to the S pole. It exits from the N pole on the back yoke 21 side, passes through the back yoke 21, and enters the S pole of the adjacent permanent magnet 22. It exits from the N pole on the magnetic gap side, interlinks with the stator coil 11, and enters the permanent magnet 22 of the first rotor 23, whose magnetic gap side is magnetized to the S pole. It exits from the N pole on the back yoke 21 side, passes through the back yoke 21, and enters the S pole of the adjacent permanent magnet 22, forming a magnetic circuit.

In this embodiment, the coil base 12 faces the first rotor 23, and the stator coil 11 faces the second rotor 24. Therefore, if the coil base 12 is made of a magnetic material, the magnetic gaps on both sides have different magnetic gap lengths. The attractive forces acting between the first rotor 23 and the second rotor 24 and the stator 10 are different, and a large stress is applied to the fixed portion of the stator 10. For this reason, it is preferable that the coil base 12 is made of a non-magnetic material. When the rotating electric machine is a permanent magnet synchronous machine, when the rotor 20 rotates, the magnetic flux in the stator 10 fluctuates. When the stator 10 has a magnetic material, the fluctuating magnetic flux causes iron loss in the magnetic material even when no load is applied or when operating at low power. When no load is applied or when operating at low power, the influence of the iron loss generated in the magnetic material of the stator 10 becomes large. When the coil base 12 is made of a non-magnetic material, no iron loss occurs.

Figure 16 is a schematic development view of another example of a rotating electric machine according to the present embodiment. As shown in Figure 16, the stator 10a has a stator coil 11a and a coil base 12. The stator coil 11a further includes a second stator coil 115 in addition to the first stator coil 114. The first stator coil 114 and the second stator coil 115 are arranged on both sides of the coil base 12 in the magnetic gap direction. The first stator coil 114 and the second stator coil 115 are wound with the same number of turns using magnet wire of the same wire diameter. The wire diameter and number of turns of the magnet wire are not limited to being the same for the first stator coil 114 and the second stator coil 115, and may be different from each other.

The first stator coil 114 and the second stator coil 115 are connected in series. This reduces the number of turns in the first stator coil 114 and the second stator coil 115 compared to when the stator coil 11 is arranged on only one side of the coil base 12 in the magnetic gap direction. Generally, as the number of turns in the stator coil increases, the coil end portion is more likely to bulge. By having the stator coil 11a have the first stator coil 114 and the second stator coil 115, the expansion of the coil end portion of the stator coil 11a is suppressed, making it possible to reduce the outer diameter of the rotating electric machine 1 and ensure the outer diameter of the shaft.

The first stator coil 114 and the second stator coil 115 may be connected in parallel. In this case, a magnet wire with a thinner wire diameter can be used to achieve the same resistance value as when the stator coil 11 is arranged on only one side of the coil base 12 in the magnetic gap direction. By using a magnet wire with a thinner wire diameter, winding bulge at the coil end portion is suppressed. When magnet wire of the same wire diameter is used, the winding resistance is smaller and copper loss due to the current flow is reduced.

The first stator coil 114 and the second stator coil 115 are arranged on either side of the coil base 12 in the magnetic gap direction. This increases the contact area between the stator coil 11 and the coil base 12. The thermal resistance between the stator coil 11 and the coil base 12 is reduced, making it easier for heat to be transferred from the stator coil 11 to the coil base 12. This suppresses the temperature rise of the stator coil 11.

Figure 17 is a diagram showing an example of a method of engaging the coil holding member 40 according to the present embodiment. When the first stator coil 114 and the second stator coil 115 are arranged on both sides of the coil base 12 in the magnetic gap direction, the coil holding member 40 is engaged with the first stator coil 114 and the second stator coil 115 as shown in Figure 17. The first stator coil is an example of a stator coil in the claims, and the second stator coil is an example of a fixed target part in the claims. Figure 18 is an enlarged view of an engagement part of the coil holding member 40 in Figure 17. As shown in Figure 18, a tensile force Ft acts between the part of the coil holding member 40 engaged with the first stator coil 114 and the part of the coil holding member 40 engaged with the second stator coil 115. This tensile force Ft causes a pressing force Fc in a direction toward the coil base 12 to act on the first stator coil 114 and the second stator coil 115. The pressing force Fc fixes the first stator coil 114 and the second stator coil 115 to the coil base 12. As a result, the stator coil 11a is mechanically fixed to the coil base 12, and then the coil base 12 is fixed to the frame 30 or the bracket 32, improving the workability of the assembly process of the coil base 12.

When the coil holding member 40 is engaged with the first stator coil 114 and the second stator coil 115, the first stator coil 114 and the second stator coil 115 may be elastically deformed. This causes an elastic force to act on the first stator coil 114 and the second stator coil 115. This elastic force may generate a pressing force Fc acting on the first stator coil 114 and the second stator coil 115. The pressing force Fc may be generated by both the tensile force Ft and the elastic force.

Figure 19 is a schematic cross-sectional view of another example of a rotating electric machine according to this embodiment. The stator 10b has a stator coil 11b having a first stator coil 114a and a second stator coil 115a, and a coil base 12. The first stator coil 114a and the second stator coil 115a are each formed by bending toward the coil base 12. The coil holding member 40 is engaged with the first stator coil 114a and the second stator coil 115a at the positions where they are bent. As a result, the first stator coil 114a and the second stator coil 115a are fixed to the coil base 12. Since the coil holding member 40 is engaged with the positions where the first stator coil 114a and the second stator coil 115a are bent toward the coil base 12, the coil holding member 40 does not protrude toward the magnetic gap. In FIG. 19 , the portions that are bent toward the coil base 12 are the outer diameter side and inner diameter side coil end portions, but the portions that are bent are not limited to the outer diameter side and inner diameter side coil end portions 112, 113.

Figure 20 is a diagram showing an example of a method of engaging the coil holding member 40 according to this embodiment. The coil holding member 40 is formed of a wire-like member. One end of the coil holding member 40 is engaged with the first stator coil 114, and is hooked alternately at multiple points on the second stator coil 115 and the first stator coil 114. The other end of the coil holding member 40 is engaged with the first stator coil 114 or the second stator coil 115. In the example of Figure 20, the other end of the coil holding member 40 is engaged with the first stator coil 114, but it may also be engaged with the second stator coil 115.

A tensile force Ft acts on the coil holding member 40 at the engagement portion with the first stator coil 114 and the subsequent engagement portion with the second stator coil 115. The tensile force Ft causes a pressing force Fc to act on the first stator coil 114 and the second stator coil 115 in a direction toward the coil base 12. The pressing force Fc fixes the first stator coil 114 and the second stator coil 115 to the coil base 12. Because the coil holding member 40 engages with multiple points on the first stator coil 114 and the second stator coil 115, the stress acting on the first stator coil 114 and the second stator coil 115 is reduced.

In this engagement method, the pressing force Fc may be generated by an elastic force acting on the first stator coil 114 and the second stator coil 115, or may be generated by a tensile stress acting on the engagement portions at both ends of the coil holding member 40. It may also be generated by a combination of the above.

Figure 21 is a diagram showing an example of a stator coil 11c according to the present embodiment. When the coil holding member 40 is engaged with the outer diameter side coil end portion 112 of the stator coil 11c as in Figure 21, a coil protrusion 116 that protrudes outward may be provided at the location where the coil holding member 40 is engaged. By providing the coil protrusion 116, it is possible to operate the mounting jig for the coil holding member 40 without interfering with the surrounding outer diameter side coil end portion 112.

22 and 23 are diagrams showing an example of the coil holding member 40 according to the present embodiment. In both cases of FIG. 22 and FIG. 23, the coil holding members 40a and 40b are formed to have a pair of curved portions at both ends. In the example of FIG. 22, the coil holding member 40a is formed in an approximately C-shape, and in the example of FIG. 23, the coil holding member 40b is formed in an approximately S-shape. The coil holding members 40a and 40b have elasticity. One curved portion of the coil holding members 40a and 40b is engaged with the first stator coil 114, and the other curved portion is engaged with the second stator coil 115. An elastic force acts on both ends of the coil holding members 40a and 40b. This elastic force exerts a pressing force on each of the first stator coil 114 and the second stator coil 115 in a direction toward the coil base 12. As a result, the first stator coil 114 and the second stator coil 115 are each fixed to the coil base 12. By using the coil holding member 40 formed from an elastic body and having a pair of curved portions in this manner, the stator coil 11 is easily and mechanically fixed to the coil base 12.

The coil holding members 40a, 40b may not have elasticity. In this case, one curved portion of the coil holding members 40a, 40b is engaged with the first stator coil 114, and the other curved portion is engaged with the second stator coil 115, so that the first stator coil 114 and the second stator coil 115 are elastically deformed toward the coil base 12. An elastic force acts on the first stator coil 114 and the second stator coil 115, and this elastic force applies a pressing force to the first stator coil 114 and the second stator coil 115 in the direction of the coil base 12. As a result, the first stator coil 114 and the second stator coil 115 are fixed to the coil base 12. The pressing force acting on the first stator coil 114 and the second stator coil 115 may be generated by both the coil holding members 40 a, 40 b and the elastic force acting on the first stator coil 114 and the second stator coil 115 .

Figure 24 is a diagram showing an example of the shape of the coil base 12d according to this embodiment. A plurality of ribs 14a are provided on both sides of the magnetic gap direction of the coil base 12d, each protruding in the magnetic gap direction. The plurality of ribs 14a extend in a direction perpendicular to the rotation direction dr of the rotor 20. Adjacent ribs of the plurality of ribs 14a form a slot 15. The plurality of ribs 14a are provided corresponding to all sides 111 of the stator coil 11 perpendicular to the rotation direction dr of the rotor 20. In addition, the plurality of ribs 14a provided on the coil base 12d are provided at corresponding positions on one surface and the other surface, and the circumferential positions of the ribs 14a on both sides of the magnetic gap direction may be shifted. Figure 25 is a diagram showing the arrangement of the first stator coil 114 and the second stator coil 115 on the coil base 12d of Figure 24. Since the circumferential positions of the ribs provided on both sides of the coil base 12d in the magnetic gap direction are shifted, the circumferential positions of the first stator coil 114 and the second stator coil 115 are also different. FIG. 26 shows an enlarged view of the engagement portion of the coil holding member 40. When the coil holding member 40 is engaged with each of the first stator coil 114 and the second stator coil 115, the tensile force Ft acting on the coil holding member 40 has an axial component and a circumferential component. Since the tensile force Ft includes a circumferential component, a circumferential force Fd acts on the first stator coil 114 and the second stator coil 115 in addition to a pressing force Fc in a direction toward the coil base 12d. Due to the circumferential force Fd, the first stator coil 114 and the second stator coil 115 abut against the side surface of the rib 14a and are fixed in the circumferential direction. The rib 14 may be a protrusion as shown in the first embodiment. Furthermore, the multiple ribs 14 a do not necessarily have to correspond to all of the sides 111 of the stator coil 11 that are perpendicular to the rotation direction dr of the rotor 20 .

As in the first embodiment, the coil base 12 may be provided with a communication portion 13. The coil holding member 40 is engaged with a fixing target portion different from the stator coil 11 and the coil base 12 through the communication portion 13. When the stator coil 11a has a first stator coil 114 and a second stator coil 115, the coil holding member 40 is engaged with the first stator coil 114 and the second stator coil 115. Even when the outer diameter of the coil base 12 is larger than the outer diameter of the stator coil 11a, or when the inner diameter of the coil base 12 is smaller than the inner diameter of the stator coil 11, the stator coil 11 can be fixed to the coil base 12 using the coil holding member 40. In addition, since the coil base 12 can be made larger, space for fixing to the housing of the rotating electric machine 1 is secured.

<Effects of the Second Embodiment>
In the rotating electric machine 1 of this embodiment as well, the coil holding member 40 is engaged with the stator coil 11 and a fixing target portion different from the coil base 12. As a result, a pressing force Fc is generated in the stator coil 11 in a direction toward the coil base 12, and the stator coil 11 is mechanically fixed to the coil base 12.

In the rotating electric machine 1 of this embodiment, the number of rotors 20 is greater than the number of stators 10, and the rotors 20 are arranged on both sides of the stator 10 in the magnetic gap direction. With this configuration, the magnetic gap surface is increased, and the torque is increased.

The stator coil 11a has a first stator coil 114 and a second stator coil 115, which are arranged on either side of the coil base 12 in the magnetic gap direction. A coil holding member 40 is engaged with the first stator coil 114 and the second stator coil 115, and the first stator coil 114 and the second stator coil 115 are fixed to the coil base 12. With the first stator coil 114 and the second stator coil 115 fixed, the coil base 12 is fixed to the frame 30 or the bracket 32, improving the workability of the assembly process.

The first stator coil 114 and the second stator coil 115 are connected in series. This reduces the number of turns in the first stator coil 114 and the second stator coil 115 compared to when the stator coil 11 is arranged on only one side of the coil base 12 in the magnetic gap direction. As the number of turns increases, the winding bulge of the coil end portion increases. This configuration prevents the external dimensions of the rotating electric machine 1 from becoming larger.

The first stator coil 114 and the second stator coil 115 are connected in parallel. In this case, if a wire magnet with the same wire diameter as that in the case where the stator coil 11 is arranged only on one side of the coil base 12 in the magnetic gap direction is used, the winding resistance is reduced. If the amount of current flowing through the stator coil 11a is the same as that in the case where the stator coil 11 is arranged only on one side of the coil base 12 in the magnetic gap direction, the copper loss generated in the stator coil 11a is reduced. Under conditions where the copper loss generated in the stator coil 11a is the same as that in the case where the stator coil 11 is arranged on one side of the coil base 12, more current can be passed, so the torque increases. To make the winding resistance the same as that in the case where the stator coil 11 is arranged only on one side of the coil base 12 in the magnetic gap direction, the wire diameter of the magnet wire used is made thinner. By making the wire diameter of the magnet wire thinner, the winding bulge of the coil end portion is reduced, and the external dimensions of the rotating electric machine 1 are prevented from becoming larger.

In addition, the contact area between the stator coil 11a and the coil base 12 increases, reducing the thermal resistance between the stator coil 11a and the coil base 12. This allows the heat of the stator coil 11a to be transferred to the coil base 12, suppressing the temperature rise of the stator coil 11a. Alternatively, if the temperature rise is the same compared to when the stator coil 11 is placed only on one side of the coil base 12 in the magnetic gap direction, more current can be passed and the torque increases.

One end of the coil holding member 40 formed of a wire-like member is engaged with the first stator coil 114, and then hooked alternately at multiple points on the second stator coil 115 and the first stator coil 114. The other end of the coil holding member 40 is engaged with the first stator coil 114 or the second stator coil 115, and the first stator coil 114 and the second stator coil 115 are fixed to the coil base 12. With this configuration, the stress applied to the first stator coil 114 and the second stator coil 115 is dispersed.

The coil holding members 40a and 40b are formed to have a pair of curved portions. The curved portions of the coil holding member 40 are engaged with the first stator coil 114 and the second stator coil 115, respectively, and the first stator coil 114 and the second stator coil 115 are fixed to the coil base 12. With this configuration, the stator coil 11 is fixed to the coil base 12 in a simple process.

Ribs 14 are provided on the surface of the coil base 12 on which the stator coil 11a is arranged, so as to protrude in the direction of the magnetic gap, and the circumferential phase of the ribs 14 differs on both sides of the magnetic gap direction. When the first stator coil 114 and the second stator coil 115 are fixed by the coil holding member 40, a pressing force Fc in a direction toward the coil base 12 and a circumferential force Fd act on the first stator coil 114 and the second stator coil 115. The circumferential force Fd causes the first stator coil 114 and the second stator coil 115 to abut against the side of the ribs 14, positioning them in the circumferential direction.

In the first embodiment, the rotating electric machine 1 has one stator 10 and one rotor 20, and in the second embodiment, it has one stator 10 and two rotors 20, but as shown in Figure 27, it may be a multi-gap axial gap type rotating electric machine with two or more stators 10 and three or more rotors 20. In this case, the torque increases because the magnetic gap surface that becomes the torque generating surface increases.

In the first and second embodiments, an axial gap type rotating electric motor is used as an example, but the rotating electric motor may also be a radial gap type rotating electric motor in which the direction of the magnetic gap is perpendicular to the rotation axis 51 of the rotor 20.

1 Rotating electric machine, 10, 10a, 10b Stator,
11, 11a, 11b stator coil,
111: portion perpendicular to the direction of rotation; 112: outer diameter side coil end portion;
113 Inner diameter side coil end portion,
114, 114a, 114b first stator coil,
115, 115a, 115b second stator coil; 116 coil protrusion; 12, 12a, 12b, 12c, 12d coil base;
13 Communication portion, 14, 14a Rib, 15 Slot 20 Rotor, 21 Back yoke, 22 Permanent magnet,
23 first rotor, 24 second rotor,
30 Frame, 31, 32 Bracket 40, 40a, 40b Coil holding member, 50 Shaft, 51 Rotating shaft,
52 Bearing dr Rotation direction, Ft Tensile force, Fc Pressing force, Fd Circumferential force

Claims (17)

a rotor fixed to a shaft rotatably supported by a housing; and a stator having a stator coil and a coil base fixed to the housing,
the number of the rotors is greater than the number of the stators, and the rotors are disposed on both sides of the stator in a magnetic gap direction in which the rotors and the stators face each other;
the stator coil includes a first stator coil and a second stator coil different from the first stator coil,
the first stator coil and the second stator coil are disposed on both sides of the coil base in the magnetic gap direction,
a coil holding member that is engaged with the first stator coil and a fixing target portion that includes the second stator coil and is different from the coil base, and that presses the stator coil against the coil base and fixes the stator coil to the coil base. 2. The rotating electric machine according to claim 1, wherein the coil holding members are attached alternately to the first stator coil and the second stator coil and at a plurality of locations on the first stator coil and the second stator coil. 2. The rotating electric machine according to claim 1, wherein a portion of the stator coil where the coil holding member is attached is bent in a direction toward the coil base. The rotating electric machine according to claim 1 , wherein a communication portion is provided in the coil base, and the coil holding member passes through the communication portion. 2. The rotating electric machine according to claim 1, wherein a plurality of ribs protruding toward the rotor are provided on a surface of the coil base on which the stator coil is arranged. The rotating electric machine according to claim 5, characterized in that the multiple ribs are arranged to extend in a direction perpendicular to the rotation direction of the rotor in correspondence with all sides of the stator coil that are perpendicular to the rotation direction of the rotor, and adjacent ribs of the multiple ribs form slots into which sides of the stator coil that are perpendicular to the rotation direction of the rotor are inserted. 2. The rotating electric machine according to claim 1, wherein a plurality of ribs protruding toward the rotor are provided on a surface of the coil base on which the stator coil is arranged. The rotating electric machine according to claim 7, characterized in that the multiple ribs are arranged to extend in a direction perpendicular to the rotation direction of the rotor in correspondence with all sides of the stator coil perpendicular to the rotation direction of the rotor, and adjacent ribs of the multiple ribs form slots into which sides of the stator coil perpendicular to the rotation direction of the rotor are inserted. The rotating electric machine according to claim 8, characterized in that the plurality of ribs are provided on both sides of the coil base in the magnetic gap direction so that one side of the coil base corresponds to the other side of the coil base, and the circumferential positions of the plurality of ribs provided on both sides of the coil base are different on both sides in the magnetic gap direction. 2. The rotating electric machine according to claim 1, wherein the coil holding member is attached to only one of an inner diameter side coil end portion and an outer diameter side coil end portion of the stator coil. 2. The rotating electric machine according to claim 1, wherein the coil holding member is attached to both an inner diameter side coil end portion and an outer diameter side coil end portion of the stator coil. 2. The rotating electric machine according to claim 1, wherein a plurality of the coil holding members are attached to a plurality of positions in a circumferential direction of the stator coil. The rotating electric machine according to claim 1 , wherein the coil holding member has a pair of curved portions. The rotating electric machine according to claim 1 , wherein the coil holding member is in the form of a wire. The coil holding member is formed of an elastic body.
2. The rotating electric machine according to claim 1 . The coil holding member is formed of an elastic body.
2. The rotating electric machine according to claim 1 . The rotating electric machine according to claim 1 , wherein the rotor and the stator face each other in a direction parallel to a rotation axis of the rotor.

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