Rotating electrical machine

Abstract

A rotating electrical machine (1) comprises: a rotor (20) fixed to a shaft (50) rotatably supported by a housing; and a stator (10) having a stator coil (11) and a coil base (12) fixed to the housing. The stator coil (11) is pressed against and fixed to the coil base (12) by coil holding members (40) connected to the stator coil (11) and fixing target parts different from the coil base (12).

Description

rotating electrical machines

[0001] The present disclosure relates to a rotating electric machine in which a stator coil can be fixed easily and inexpensively.

[0002] Rotating electric machines often include coils through which current flows. In particular, when a stator coil is provided on the stator side, the stator coil needs to be fixed in place in some way to prevent movement within 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 covering both sides in the axial direction, arranging multiple stator coils in an annular shape, and molding them with resin.

[0003] Special Publication No. 2013-537797

[0004] However, conventional methods require a resin molding process, which increases costs, and there are also problems with the molding resin deteriorating as the ambient temperature rises, reducing the strength with which the stator coil is fixed.

[0005] The present disclosure has been made to solve the above-mentioned problems, 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 ambient temperature rises.

[0006] The rotating electric machine of the present disclosure comprises a rotor rotatably supported on a housing having a frame and a bracket, a stator having a stator coil and a coil base fixed to the housing, and a coil holding member, and the coil holding member is engaged with a fixing target part different from the stator coil and the coil base, and the stator coil is fixed to the coil base.

[0007] Because the stator coil is fixed using a coil holding member, complicated processes such as resin molding are not required, which helps to suppress increases in costs. Furthermore, because the stator coil is mechanically fixed, the fixing strength of the stator coil is maintained even when the environmental temperature rises.

[0008] 17 is a schematic development view of a rotating electric machine according to embodiment 1. FIG. 18 is a diagram showing an example of a stator coil. FIG. 19 is a schematic cross-sectional view of a rotating electric machine according to embodiment 1. FIG. 20 is a partial enlargement of FIG. 3. FIG. 21 is an enlarged view of a portion of a stator coil fixed to a coil base. FIG. 22 is a schematic cross-sectional view of a stator coil having another shape according to embodiment 1. FIG. 22 is a diagram showing an example of a coil base according to embodiment 1. FIG. 23 is a diagram showing a stator coil arranged on the coil base of FIG. 7. FIG. 24 is a diagram showing another example of the coil base according to embodiment 1. FIG. 25 is a diagram showing a stator coil arranged on the coil base of FIG. 9. FIG. 26 is a diagram showing a case where a communication portion is provided in the coil base. FIG. 27 is a diagram showing a stator coil arranged on the coil base of FIG. 11. FIG. 28 is a diagram showing another method of fixing a stator coil to a coil base. FIG. 29 is a partial enlargement of FIG. 3. FIG. 30 is a schematic development view of a rotating electric machine according to embodiment 2. FIG. 31 is a schematic development view of an example of a rotating electric machine according to embodiment 2. FIG. 32 is a schematic cross-sectional view of an example of a rotating electric machine according to embodiment 2. FIG. 33 is a partial enlargement of FIG. 34. 25 is a diagram showing an example of a method for engaging a coil holding member according to embodiment 2. FIG. 26 is a diagram showing an example of a stator coil according to embodiment 2. FIG. 27 is a diagram showing an example of a coil holding member according to embodiment 2. FIG. 28 is a diagram showing an example of a coil base shape according to embodiment 2. FIG. 29 is a diagram showing a stator coil fixed to the coil base of FIG. 24. FIG. 29 is an enlarged view of the coil holding member engagement portion of FIG. 25. FIG. 30 is a schematic development view of a rotating electric machine according to another embodiment.

[0009] First Embodiment A rotating electric machine according to an embodiment of the present disclosure will now 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 the rotation axis 51 will be used for description. Note that structural components are not shown in FIG. 1. The rotating electric machine has a rotor 20 and a stator 10.

[0010] 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. A plurality of segment-shaped permanent magnets 22 are used. The plurality of permanent magnets 22 are arranged at an equal angular pitch in the circumferential direction in the radially intermediate portion of the back yoke 21.

[0011] The permanent magnets 22 are formed in a fan shape. Each permanent magnet 22 is magnetized in the axial direction so that its axial end face has a north pole or a south pole. When viewed from the axial direction, the permanent magnets 22 are arranged so that their north and south poles are alternately aligned in the circumferential direction. Note that the permanent magnet 22 is not limited to a segment-shaped magnet, but may be formed as a single hollow disk. In this case, the permanent magnet 22 is magnetized so that its north and south poles appear alternately in the circumferential direction. Furthermore, any number of permanent magnets 22 with multiple poles may be used.

[0012] The stator 10 has multi-phase stator coils 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 phase windings, which are distributed windings that overlap each other in the circumferential direction. The stator coil 11 may also be concentrated windings, in which the windings do not overlap each other. The windings are generally fan-shaped and have a pair of sides 111 that are 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. The radial length of the sides 111 is approximately equal to the radial length of the substantially fan-shaped permanent magnets 22, allowing for effective use of the magnetic flux generated by the permanent magnets 22. The stator coil 11 is positioned and fixed on the coil base 12, which is formed in a substantially hollow disk shape. A method for fixing the stator coil 11 to the coil base 12 will be described later.

[0013] 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 be substantially disc-shaped and axially opposed to each other. The rotor 20 is fixed to a shaft 50. The shaft 50 is rotatably supported via a bearing 52 by brackets 31 and 32, which have bearing holders in their centers. The brackets 31 and 32 are formed into a substantially hollow disc shape and made of a non-magnetic material such as aluminum. The shaft 50 may be formed of either a magnetic or 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 into a cylindrical shape and made of a non-magnetic material such as aluminum.

[0014] The flow of magnetic flux within the rotating electric machine 1 according to the present disclosure will be described. The magnetic flux emitted from the permanent magnet 22 with an 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 an S pole on the magnetic gap side of the rotor 20. The magnetic flux emitted from the permanent magnet 22 with an N pole on the back yoke 21 side passes through the back yoke 21 and enters the permanent magnet 22 with an S pole on the back yoke 21 side. The magnetic flux makes one circuit within the rotating electric machine 1, forming a magnetic circuit. In a radial gap type, the magnetic flux flows two-dimensionally within the same plane, but the rotating electric machine 1 according to the present disclosure differs in that the magnetic flux flows three-dimensionally.

[0015] The torque generation principle of the rotating electric machine 1 of the present disclosure is the same as that of a 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. Generally, the increase in stator coil temperature due to copper loss determines the maximum value of the current passed through the stator coil 11.

[0016] The coil base 12 may be, for example, a wound core formed by concentrically winding a thin magnetic plate such as an electromagnetic steel plate, or a pressed powder core formed by pressing insulatingly coated soft magnetic iron powder. The coil base 12 may also be formed from a non-magnetic material such as resin. If the coil base 12 is formed from a magnetic material, the magnetic reluctance of the magnetic circuit in the rotating electric machine 1 decreases, and the torque increases.

[0017] A method for fixing the stator coil 11 will be described with reference to FIGS. 3, 4, and 5. FIG. 4 is a diagram showing an example of a method for engaging the coil holding member 40. FIG. 5 is a partial 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 on and temporarily fixed to the coil base 12, the coil base 12 is fixed to the bracket 32. Then, as shown in FIG. 4, one end of a wire-like coil holding member 40, such as a wire or piano wire, is engaged with the stator coil 11. Then, the other end of the coil holding member 40 is engaged by, for example, welding to a fixing target portion different from the coil base 12, such as the frame 30 or a housing including the bracket 32. The wire-like coil holding member 40 may be made of a racing material or a string-like resin member.

[0018] At this time, as shown in Fig. 5, the coil holding member 40 is engaged with the stator coil 11 so that a tensile force Ft acts on the engaging 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, fixing the stator coil 11 to the coil base 12. In the example of Fig. 3, one end of the coil holding member 40 is engaged with the outer diameter side coil end portion 112 of the stator coil 11, and the other end is engaged with the frame 30, making the frame 30 the fixing target. Furthermore, one end of the coil holding member 40 is engaged with the inner diameter side coil end portion 113 of the stator coil 11, and the other end is engaged with the bracket 32, making the bracket 32 ​​the fixing target.

[0019] 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 the stator coil 11 is mechanically fixed to the coil base 12 without using adhesive or molding resin. This eliminates the need for complex processes such as adhesive coating or molding, making it possible to suppress increases in costs. Furthermore, if adhesive or molding resin is used to fix the stator coil 11, the fixing strength of the stator coil 11 decreases in high-temperature environments due to a decrease in the adhesive strength of the adhesive and thermal degradation of the molding 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 fixing strength is maintained even in high-temperature environments.

[0020] 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 the bracket 32, to fix the stator coil 11 to the coil base 12. In this case, space is secured on the inner diameter side, so the diameter of the shaft 50 is increased and the rigidity of the shaft 50 is increased.

[0021] 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, and therefore it is possible to prevent the outer diameter of the rotating electric machine 1 from becoming larger.

[0022] A plurality of coil holding members 40 may be engaged with the stator coil 11 and a fixing target other than the coil base 12, such as the frame 30 or bracket 32, at equal angular pitches in the circumferential direction, thereby fixing the stator coil 11 to the coil base 12. Fixing the stator coil 11 to the coil base 12 with a plurality of coil holding members 40 distributes the force that the stator coil 11 receives from the coil holding members 40. This prevents excessive stress from being applied to a portion of the stator coil 11. It is also preferable to fix the stator coil 11 by engaging the coil holding members 40 in diagonal order. This improves the accuracy of the parallelism of the surfaces of the stator 10 facing the rotor 20.

[0023] 3, the coil base 12 is fixed to the bracket 32, but may be fixed to the frame 30. Furthermore, one end of the coil holding member 40, one end of which is 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, similar to the coil holding member 40, one end of which is engaged with the inner diameter side coil end portion 113. Furthermore, 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 points of engagement of the coil holding member 40 with 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.

[0024] Although the case where the pressing force Fc acting on the stator coil 11 is generated by the tensile force Ft from the coil holding member 40 has been described, 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. Also, the coil holding member 40 may be elastic, and when the coil holding member 40 engages with the stator coil 11 and a fixing 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. Also, the pressing force Fc may be generated by a combination of the above.

[0025] 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 these formed portions. This makes it possible to prevent the coil holding member 40 from protruding toward the rotor 20 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, and may be a pair of sides 111.

[0026] The coil holding member 40 may be made of a material with 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 a temperature rise in the stator coil 11.

[0027] Fig. 7 is a diagram showing an example of a coil base 12a according to this embodiment. The coil base 12a has protruding ribs 14 that protrude toward the magnetic gap on the surface facing the magnetic gap and on which the stator coil 11 is disposed. Fig. 8 is a diagram showing the stator coil 11 disposed on the coil base 12a on which the protruding ribs 14 are disposed. A pair of edges 111 abut against the ribs 14, thereby determining the circumferential position of the stator coil 11. In the example shown in Fig. 7, the protruding ribs 14 are provided so as to correspond to all pairs of edges 111 that are perpendicular to the rotation direction dr of the rotor 20, but they do not necessarily need to correspond to all edges 111.

[0028] FIG. 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 this embodiment, this corresponds to the radial direction. The ribs 14a are provided at equal angular pitches in the circumferential direction, and two adjacent ribs 14a form slots 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. FIG. 10 is a diagram showing the stator coil 11 arranged on the coil base 12b of FIG. 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.

[0029] Fig. 11 is a diagram showing a case where a communication portion 13 is provided in the coil base 12c. Fig. 12 is a diagram showing a state where the stator coil 11 is arranged on this coil base 12c. As shown in Fig. 11, the communication portion 13 is provided in the coil base 12c, 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. Furthermore, since the coil base 12c can be made larger, space for fixing to the bracket 32 ​​is secured.

[0030] FIG. 13 is a diagram showing another method of fixing the stator coil 11 to the coil base 12. FIG. 14 is a partial enlarged view of FIG. 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 side opposite 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 fixing target portion. As shown in FIG. 14 , a tension Ft acts on the coil holding member 40 at the portion where it engages with the outer diameter side coil end portion 112 of the stator coil 11 and at the portion where it abuts against the coil base 12. This tension Ft causes a pressing force Fc to act on the stator coil 11 in the direction toward the coil base 12, fixing the stator coil 11 to the coil base 12.

[0031] In this case, radial slots 15 may be provided on the surface of the coil base 12 opposite to the magnetic gap. 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.

[0032] 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, which improves the workability of the attachment work.

[0033] Effect 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. This generates a pressing force Fc on 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.

[0034] 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 or 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 a high-temperature environment.

[0035] 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 can be secured in the inner diameter portion. The outer diameter of the shaft 50 becomes larger, and the rigidity of the shaft 50 becomes higher.

[0036] When the coil holding member 40 is engaged only with the inner diameter side coil end portion 113, there is no need for a structure on the outer diameter side for engaging the coil holding member 40. This prevents the outer diameter of the rotating electric machine 1 from becoming large.

[0037] Furthermore, the coil holding member 40 may 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.

[0038] Furthermore, the coil holding members 40 may be engaged at multiple locations in the circumferential direction. This configuration distributes the stress acting on the stator coil 11. Furthermore, by engaging the coil holding members 40 in order on a diagonal line, the accuracy of the parallelism of the magnetic gap surface of the stator coil 11 is improved.

[0039] Furthermore, the coil holding member 40 may be formed in a wire shape. With this configuration, the stator coil 11 is mechanically fixed.

[0040] Furthermore, the portion of the stator coil 11 where the coil holding member 40 engages may be bent in a direction toward the coil base 12. With this configuration, the coil holding member 40 does not protrude toward the magnetic gap side.

[0041] In addition, the heat transfer coefficient of the coil holding member 40 is high. With this configuration, heat from the stator coil 11 is transferred to the coil holding member 40 and dissipated from the coil holding member 40. This suppresses a rise in the temperature of the stator coil 11.

[0042] Furthermore, the coil base 12a is provided with a communication portion 13, and the coil holding member 40 connects the stator coil 11 to a fixing 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 can be mechanically fixed using the coil holding member 40.

[0043] Furthermore, a plurality of protruding ribs 14 that protrude in the direction of the magnetic gap are provided on the surface of the coil base 12b that faces the magnetic gap and on which the stator coil 11 is disposed. With this configuration, the sides 111 of the stator coil 11 that are perpendicular to the rotation direction dr of the rotor 20 abut against the side surfaces of the ribs 14 and are fixed. This determines the circumferential position of the stator coil 11.

[0044] Furthermore, the ribs 14a are provided extending in a direction perpendicular to the rotation direction dr of the rotor 20. The multiple ribs 14a are provided corresponding to all of the sides 111 of the stator coil 11 that are perpendicular to the rotation direction dr of the rotor 20, and slots 15 are formed between adjacent multiple ribs 14a. The sides 111 of the stator coil 11 that are 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 and are fixed to the side surfaces of the ribs 14a, thereby determining the circumferential position of the stator coil 11. Furthermore, because the stator coil 11 is assembled along the ribs 14a, assembly can be performed using an automatic winding machine.

[0045] Furthermore, in the rotating electric machine according to the first embodiment, the magnetic gap direction of the rotating electric machine 1 is parallel to the rotation axis 51 of the rotating electric machine 1. With this configuration, the magnetic gap surface is increased in a flat structure, and torque is increased.

[0046] Second Embodiment A rotating electric machine 1 according to the second embodiment will be described below with reference to the drawings, focusing on differences from the rotating electric machine 1 according to the first embodiment. FIG. 15 is a schematic development view of a rotating electric machine according to the second embodiment. Rotors 20 are disposed on both sides of a stator 10 in the magnetic gap direction. The basic structures of the stator 10 and the rotors 20 are the same as those of the first embodiment. One rotor 20 is designated as a first rotor 23, and the other rotor 20 is designated as a 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. The permanent magnets 22 of the first rotor 23 and the second rotor 24, which are disposed at the same circumferential phase, are magnetized with opposite 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. 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 be arranged at different circumferential phases.

[0047] The magnetic circuit of the rotating electric machine according to the second embodiment will be described. The magnetic flux emitted from the permanent magnet 22 of the first rotor 23, whose magnetic gap side is magnetized to an 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 an S pole. The magnetic flux 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. The magnetic flux 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 an S pole. The magnetic flux 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, completing a magnetic circuit.

[0048] 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 differ, resulting in significant stress on the fixed portion of the stator 10. Therefore, it is preferable that the coil base 12 be made of a non-magnetic material. When the rotating electric machine is a permanent magnet synchronous machine, the magnetic flux in the stator 10 fluctuates as the rotor 20 rotates. If the stator 10 contains a magnetic material, the fluctuating magnetic flux generates iron loss in the magnetic material even during no-load or low-power operation. During no-load or low-power operation, the impact of this iron loss generated in the magnetic material of the stator 10 becomes significant. If the coil base 12 is made of a non-magnetic material, iron loss does not occur.

[0049] FIG. 16 is a schematic development view of another example of a rotating electric machine according to this embodiment. As shown in FIG. 16 , a 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 a 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 do not have to be the same for the first stator coil 114 and the second stator coil 115, and may be different from each other.

[0050] 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 a stator coil increases, the coil end portions tend to bulge. By including the first stator coil 114 and the second stator coil 115 in the stator coil 11a, the expansion of the coil end portions 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.

[0051] 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 maintain 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. Using a magnet wire with a thinner wire diameter suppresses winding bulge at the coil end. When using magnet wire with the same wire diameter, the winding resistance is smaller, and copper loss due to the current flow is reduced.

[0052] 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. This reduces the thermal resistance between the stator coil 11 and the coil base 12, 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.

[0053] FIG. 17 is a diagram showing an example of a method for 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 FIG. 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 portion in the claims. FIG. 18 is an enlarged view of an engagement portion of the coil holding member 40 in FIG. 17 . As shown in FIG. 18 , a tensile force Ft acts between the portion of the coil holding member 40 engaged with the first stator coil 114 and the portion of the coil holding member 40 engaged with the second stator coil 115. This 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. 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.

[0054] 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. As a result, an elastic force acts 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.

[0055] 19 is a schematic cross-sectional view of another example of a rotating electric machine according to this embodiment. The stator 10b includes 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 them toward the coil base 12. A coil holding member 40 is engaged with the bent portions of the first stator coil 114a and the second stator coil 115a, respectively. This fixes the first stator coil 114a and the second stator coil 115a to the coil base 12. Because the coil holding member 40 is engaged with the bent portions of the first stator coil 114a and the second stator coil 115a, respectively, the coil holding member 40 does not protrude toward the magnetic gap. In Figure 19, the parts that are bent and molded toward the coil base 12 are the outer diameter side and inner diameter side coil end parts, but the parts that are bent and molded are not limited to the outer diameter side and inner diameter side coil end parts 112, 113.

[0056] 20 is a diagram showing an example of a method for 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 FIG. 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.

[0057] A tensile force Ft acts on the coil holding member 40 at an engaging portion with the first stator coil 114 and an engaging portion with the subsequent 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 the first stator coil 114 and the second stator coil 115 at multiple locations, the stress acting on the first stator coil 114 and the second stator coil 115 is reduced.

[0058] In this engagement method, the pressing force Fc may also 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. Alternatively, the pressing force Fc may be generated by a combination of the above.

[0059] Fig. 21 is a diagram showing an example of a stator coil 11c according to this embodiment. When the coil holding member 40 is engaged with the outer diameter side coil end portion 112 of the stator coil 11c as shown in Fig. 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 attachment jig for the coil holding member 40 without interfering with the surrounding outer diameter side coil end portion 112.

[0060] 22 and 23 are diagrams showing an example of a coil holding member 40 according to the present embodiment. In both of FIGS. 22 and 23 , the coil holding members 40 a, 40 b are formed to have a pair of curved portions at both ends. In the example of FIG. 22 , the coil holding member 40 a is formed in a generally C-shape, and in the example of FIG. 23 , the coil holding member 40 b is formed in a generally S-shape. The coil holding members 40 a, 40 b are elastic. One curved portion of the coil holding members 40 a, 40 b engages with the first stator coil 114, and the other curved portion engages with the second stator coil 115. An elastic force acts on both ends of the coil holding members 40 a, 40 b. This elastic force applies a pressing force to 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 mechanically fixed to the coil base 12 in an easy manner.

[0061] The coil holding members 40a, 40b do not need to 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, causing the first stator coil 114 and the second stator coil 115 to elastically deform 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 toward 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 and 40 b and the elastic force acting on the first stator coil 114 and the second stator coil 115 .

[0062] FIG. 24 is a diagram showing an example of the shape of the coil base 12d according to this embodiment. A plurality of ribs 14a protruding in the magnetic gap direction are provided on both sides of the coil base 12d in the magnetic gap direction. The 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 slots 15. The ribs 14a are provided corresponding to all sides 111 of the stator coil 11 perpendicular to the rotation direction dr of the rotor 20. Furthermore, the ribs 14a provided on the coil base 12d may be provided at corresponding positions on one side and the other side, and the circumferential positions of the ribs 14a on both sides of the magnetic gap direction may be offset. FIG. 25 is a diagram showing the arrangement of a first stator coil 114 and a second stator coil 115 on the coil base 12d of FIG. 24 . Because the circumferential positions of the ribs provided on both sides of the coil base 12d in the magnetic gap direction are offset, the circumferential positions of the first stator coil 114 and the second stator coil 115 are also different. Figure 26 shows an enlarged view of the engagement portion of the coil holding member 40. When the coil holding member 40 engages with the first stator coil 114 and the second stator coil 115, a tensile force Ft acting on the coil holding member 40 has an axial component and a circumferential component. The circumferential component of the tensile force Ft causes a circumferential force Fd to act on the first stator coil 114 and the second stator coil 115 in addition to a pressing force Fc toward the coil base 12d. The circumferential force Fd causes the first stator coil 114 and the second stator coil 115 to abut against the side surfaces of the ribs 14a and be fixed in the circumferential direction. The ribs 14 may be protruding, as shown in the first embodiment. Furthermore, the plurality of 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 .

[0063] 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. Furthermore, since the coil base 12 can be made larger, space for fixing the coil base 12 to the housing of the rotating electric machine 1 can be secured.

[0064] Effect of 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 on 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.

[0065] 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 stators 10 in the magnetic gap direction. With this configuration, the magnetic gap surface is increased, and torque is increased.

[0066] 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 respectively fixed to the coil base 12. Since the coil base 12 is fixed to the frame 30 or the bracket 32 ​​with the first stator coil 114 and the second stator coil 115 fixed, workability in the assembly process is improved.

[0067] 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 at the coil end portion increases. This configuration prevents the external dimensions of the rotating electric machine 1 from becoming larger.

[0068] 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 when the stator coil 11 is arranged on only one side of the coil base 12 in the magnetic gap direction is used, the winding resistance will be reduced. If the amount of current flowing through the stator coil 11a is the same as that when the stator coil 11 is arranged on only one side of the coil base 12 in the magnetic gap direction, the copper loss generated in the stator coil 11a will be reduced. Under conditions where the copper loss generated in the stator coil 11a is the same as that when the stator coil 11 is arranged on only one side of the coil base 12, more current can be passed, thereby increasing torque. To make the winding resistance the same as that when the stator coil 11 is arranged on only one side of the coil base 12 in the magnetic gap direction, the wire diameter of the magnet wire used will be smaller. By using a smaller wire diameter magnet wire, the winding bulge at the coil end will be smaller, and the external dimensions of the rotating electric machine 1 will be prevented from becoming larger.

[0069] Furthermore, 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 heat from the stator coil 11a to be transferred to the coil base 12, suppressing a temperature rise in the stator coil 11a. Alternatively, if the temperature rise is the same as when the stator coil 11 is disposed on only one side of the coil base 12 in the magnetic gap direction, more current can be passed through, increasing the torque.

[0070] One end of the coil holding member 40 formed from a wire-like member is engaged with the first stator coil 114, and then the end 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, and the first stator coil 114 and the second stator coil 115 are fixed to the coil base 12. With this configuration, stress acting on the first stator coil 114 and the second stator coil 115 is dispersed.

[0071] The coil holding members 40a, 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 can be fixed to the coil base 12 in a simple process.

[0072] Ribs 14 are provided on the surface of the coil base 12 on which the stator coil 11a is arranged, protruding in the direction of the magnetic gap, and the circumferential phase of the ribs 14 differs on either side of the magnetic gap. 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 surfaces of the ribs 14, positioning them circumferentially.

[0073] 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 Fig. 27, it may be an axial gap type rotating electric machine with multiple gaps, having two or more stators 10 and three or more rotors 20. In this case, the torque increases because the magnetic gap surface that serves as the torque generating surface increases.

[0074] In the first and second embodiments, an axial gap type rotating electric machine has been described as an example, but the rotating electric machine may also be a radial gap type rotating electric machine in which the direction of the magnetic gap is perpendicular to the rotation axis 51 of the rotor 20.

[0075] REFERENCE SIGNS LIST 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 tension force, Fc pressing force, Fd circumferential force

Claims

1. A rotating electrical machine comprising a rotor fixed to a shaft rotatably supported by a housing, a stator having a stator coil and a coil base fixed to the housing, wherein the stator coil is pressed and fixed to the coil base by a coil holding member engaged with the stator coil and a fixing target portion different from the coil base.

2. The rotating electrical machine according to claim 1, wherein the number of the rotors is larger than the number of the stators, and the rotors are arranged on both sides of the stator in the magnetic gap direction where the rotors and the stator face each other.

3. The rotating electrical machine according to any one of claims 1 or 2, wherein the fixing target portion includes the housing.

4. The stator coil is a first stator coil, the rotating electrical machine further includes a second stator coil different from the first stator coil, and the first stator coil and the second stator coil are arranged on both sides of the coil base in the magnetic gap direction respectively. The rotating electrical machine according to claim 2.

5. The rotating electrical machine according to claim 4, wherein the fixing target portion includes the second stator coil.

6. The rotating electrical machine according to claim 5, wherein the coil holding member is alternately attached to the first stator coil and the second stator coil, and at a plurality of locations of the first stator coil and the second stator coil.

7. The rotating electrical machine according to any one of claims 1 to 4, wherein the location where the coil holding member of the stator coil is attached is bent and formed in a direction toward the coil base.

8. The rotating electrical machine according to any one of claims 1 to 4, wherein a communication portion is provided in the coil base, and the coil holding member passes through the communication portion.

9. The rotating electrical machine according to claim 1, wherein a plurality of ribs protruding in the direction of the rotor are provided on the surface of the coil base where the stator coil is arranged.

10. The plurality of ribs are provided so as to extend in a direction orthogonal to the rotation direction of the rotor for all sides of the stator coil orthogonal to the rotation direction of the rotor, and slots are formed by adjacent ribs of the plurality of ribs, and sides of the stator coil orthogonal to the rotation direction of the rotor are inserted into the slots. The rotating electrical machine according to claim 9, wherein:

11. The rotating electrical machine according to any one of claims 2 or 4, wherein a plurality of ribs protruding in the direction of the rotor are provided on a surface of the coil base on which the stator coil is disposed.

12. The plurality of ribs are provided so as to extend in a direction orthogonal to the rotation direction of the rotor for all sides of the stator coil orthogonal to the rotation direction of the rotor, and slots are formed by adjacent ribs of the plurality of ribs, and sides of the stator coil orthogonal to the rotation direction of the rotor are inserted into the slots. The rotating electrical machine according to claim 11, wherein:

13. The plurality of ribs are provided on both sides of the coil base in the magnetic gap direction so as to correspond to each other on one surface and the other surface of the coil base, and 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. The rotating electrical machine according to any one of claims 11 or 12, wherein:

14. The rotating electrical machine according to any one of claims 1 to 4, wherein the coil holding member is attached only to either the inner diameter side coil end portion or the outer diameter side coil end portion of the stator coil.

15. The rotating electrical machine according to any one of claims 1 to 4, wherein the coil holding member is attached to both the inner diameter side coil end portion and the outer diameter side coil end portion of the stator coil.

16. The rotating electrical machine according to any one of claims 1 to 4, wherein a plurality of the coil holding members are attached to a plurality of locations in the circumferential direction of the stator coil.

17. The rotating electrical machine according to claim 5, wherein the coil holding member has a pair of curved portions.

18. The rotating electrical machine according to any one of claims 1 to 16, wherein the coil holding member is wire-shaped.

19. The rotating electrical machine according to any one of claims 1 to 18, wherein the coil holding member is formed of an elastic body.

20. The rotating electrical machine according to any one of claims 1 to 19, wherein the coil holding member is formed of a member having a high heat transfer coefficient.

21. The rotating electrical machine according to any one of claims 1 to 20, wherein the direction in which the rotor and the stator face each other is parallel to the rotation axis of the rotor.

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