Rotating electric machine

Abstract

The rotating electrical machine is attached to a drive object, and includes: an electric motor having a rotating shaft, a rotor fixed to the rotating shaft, and a stator disposed outside the rotor; and a motor housing that houses the motor, the motor housing having: a cylindrical portion that extends in the axial direction of the rotating shaft and fixes the stator; a bottom portion covering one end portion of the cylindrical portion in the axial direction; and a flange portion protruding from the outer peripheral surface of the bottom portion, the flange portion having a mounting surface that comes into contact with a housing of a drive object and is fixed to the housing, and the ratio of the thickness of the bottom portion to the thickness of the flange portion being 1 or more.

Description

Technical Field

[0001] The present disclosure relates to rotating electrical machines. Background Art

[0002] The rotating electric machine is mounted on a driven object and transmits the driving force generated by the electric motor of the rotating electric machine to the driven object. Patent document 1 discloses an electric power steering device that adds the driving force generated by the electric motor to the steering mechanism of a vehicle as a steering assist force. The electric power steering device includes a gear mechanism that transmits the driving force of the electric motor to the driven object of the steering mechanism and a gear housing that accommodates the gear mechanism. A motor housing that accommodates the electric motor is fixed to the gear housing. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent No. 4926407 Summary of the invention Technical problem to be solved by the invention

[0004] In Patent Document 1, a metal plate for damping vibration is provided between the motor housing and the gear housing of the rotating electrical machine to suppress transmission of vibration of the rotating electrical machine to the gear mechanism. In this case, the number of components increases, and the number of man-hours required to assemble the rotating electrical machine to the driven object also increases.

[0005] The present invention has been made to solve the above-mentioned technical problems, and an object of the present invention is to provide a rotating electric machine capable of suppressing an increase in the number of components and suppressing transmission of vibration of the rotating electric machine to a driven object. Technical solutions to technical problems

[0006] The rotating electric machine involved in the present disclosure is a rotating electric machine installed on a driven object, including: an electric motor having a rotating shaft, a rotor fixed to the rotating shaft, and a stator arranged on the outside of the rotor; and a motor housing, which accommodates the electric motor, and the motor housing has: a cylindrical portion, which extends along the axial direction of the rotating shaft and fixes the stator; a bottom, which covers an end portion of the cylindrical portion in the axial direction; and a flange portion, which protrudes from the outer peripheral surface of the bottom, the flange portion has a mounting surface that abuts against and is fixed to the outer shell of the driven object, and the ratio of the thickness of the bottom to the thickness of the flange portion is greater than 1. Effects of the Invention

[0007] According to the present invention, it is possible to provide a rotating electrical machine capable of suppressing an increase in the number of components and suppressing transmission of vibration of the rotating electrical machine to a driven object. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a schematic cross-sectional view of the rotating electrical machine according to the first embodiment. Figure 2 This is a graph showing the relationship between the vibration value of the driven object and the right angle index of the mounting surface after the motor case is assembled to the housing of the driven object. Figure 3 This is a graph showing the relationship between the right angle index of the mounting surface after the motor case is assembled to the case of the driven object and the ratio of the thickness of the bottom portion to the thickness of the flange portion. Figure 4 It is a cross-sectional view showing a main part of the rotating electrical machine according to the second embodiment. Figure 5 It is a cross-sectional view showing a main part of a rotating electrical machine according to the third embodiment. Figure 6 This is a diagram showing a main portion of a rotating electrical machine according to a third embodiment as viewed from below. Figure 7 This is a diagram showing a main portion of a rotating electrical machine according to a modification of the third embodiment, as viewed from below. Figure 8 This is a schematic cross-sectional view of a rotating electrical machine according to a fourth embodiment. Fig. 9 The graph shows the values ​​of the short pitch winding factor, the distributed winding factor, and the winding factor in permanent magnet synchronous motors having 8 poles and 9 slots, 10 poles and 9 slots, 10 poles and 12 slots, and 14 poles and 12 slots. Fig.10 This is a schematic cross-sectional view of a rotating electrical machine according to the fifth embodiment. Fig.11 It is a perspective view of an electric power steering device according to a sixth embodiment. Fig.12 This is a schematic cross-sectional view of a rotating electrical machine according to a modified example of the first embodiment. DETAILED DESCRIPTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The scope of the present disclosure is not limited to the following embodiments, and can be arbitrarily changed within the technical concept of the present disclosure.

[0010] Implementation method 1. Figure 1 1 is a schematic cross-sectional view of a rotating electrical machine 1. The rotating electrical machine 1 includes a motor 10, a motor housing 21, and an upper housing 27. The motor 10 includes a rotating shaft 11, a stator 12, and a rotor 13. The rotating electrical machine 1 is mounted on a driven object 100, and transmits a driving force generated by the motor 10 of the rotating electrical machine 1 to the driven object 100. In the following description, the direction in which the central axis O of the electric shaft 11 extends is sometimes referred to as the axial direction. The rotating electrical machine 1 and the driven object 100 are arranged in the axial direction. In addition, in the axial direction, the side where the rotating electrical machine 1 is located is sometimes referred to as the upper side, and the side where the driven object 100 is located is sometimes referred to as the lower side or the output side. The observation from the axial direction is sometimes referred to as the top view. In the top view, the direction intersecting the central axis O is sometimes referred to as the radial direction, and the direction rotating around the central axis O is sometimes referred to as the circumferential direction.

[0011] The lower end of the rotating shaft 11 is used as an output end 11a. A sleeve 15 connected to the driven object 100 is installed at the output end 11a. The output of the motor 10 is transmitted to the driven object 100 via the output end 11a. In addition, when the rotating electric machine 1 is used, the axial direction of the rotating shaft 11 may not be consistent with the vertical direction.

[0012] The stator 12 is arranged radially outside the rotor 13 with a gap therebetween. The stator 12 has a stator core 12a and a coil 12b formed by winding a winding on the stator core 12a through an insulator 12c. The stator core 12a is formed, for example, by stacking a plurality of electromagnetic steel sheets in the axial direction. The outer periphery of the stator core 12a is formed in a circular shape. The stator core 12a is fixed to the motor housing 21.

[0013] The rotor 13 is fixed to the rotating shaft 11. The rotor 13 rotates by magnetic flux generated from the stator core 12a when electricity is supplied to the coil 12b. In addition, the rotating shaft 11, the stator 12, and the rotor 13 are arranged coaxially.

[0014] The motor case 21 accommodates the motor 10 and is fixed to the housing 101 of the driven object 100 . The motor case 21 is made of metal. As a specific material of the motor case 21, for example, an aluminum alloy is preferable. The motor case 21 is produced by cutting a molded body obtained from an aluminum alloy by die casting or the like, for example.

[0015] The motor case 21 has a cylindrical portion 22, a bottom portion 23, a plurality of flange portions 24, and a positioning portion 25. The cylindrical portion 22, the bottom portion 23, the flange portion 24, and the positioning portion 25 are integrally formed.

[0016] The cylindrical portion 22 extends in the axial direction. The stator core 12a of the stator 12 is fixed in the cylindrical portion 22 by press-fitting, shrink-fitting or the like.

[0017] The bottom portion 23 is in the shape of a disk. The bottom portion 23 covers the lower end portion of the cylindrical portion 22. A bearing fixing portion 23a is provided at the center portion of the bottom portion 23 when viewed from above. The bearing fixing portion 23a is provided so as to protrude upward from the upper surface of the bottom portion 23. The bearing fixing portion 23a is formed with a through hole through which the rotating shaft 11 passes. The first bearing 16 is mounted in the through hole of the bearing fixing portion 23a.

[0018] The flange portion 24 is provided so as to protrude radially outward from the outer peripheral surface of the bottom portion 23. In the present embodiment, the number of the flange portions 24 is 2. The number of the flange portions 24 may be 3 or more. The flange portion 24 is formed with bolt holes 24a through which the bolts 103 are inserted.

[0019] The positioning part 25 is cylindrical and is provided to protrude downward from the lower surface of the bottom 23. The positioning part 25 is inserted into an opening 101a formed in the upper part of the housing 101 of the driven object 100. The positioning part 25 positions the motor housing 21 relative to the housing 101.

[0020] The flange portion 24 and the portion of the bottom portion 23 located outside the positioning portion 25 form the mounting portion 21a of the motor housing 21. The mounting portion 21a is mounted on the housing 101. The height of the lower surface of the portion of the bottom portion 23 located outside the positioning portion 25 is equal to the height of the lower surface of the flange portion 24. That is, the lower surface of the portion of the bottom portion 23 located outside the positioning portion 25 is the same surface as the lower surface of the flange portion 24, forming the lower surface of the mounting portion 21a. The lower surface of the mounting portion 21a is referred to as the mounting surface 21b. The mounting surface 21b is in contact with the upper surface of the housing 101 and is fixed to the housing 101.

[0021] like Figure 1 As shown, the thickness of the bottom 23 (i.e., the length of the bottom 23 in the axial direction) is set to T1, and the thickness of the flange 24 (i.e., the length of the flange 24 in the axial direction) is set to T2. The ratio of the thickness T1 of the bottom 23 to the thickness T2 of the flange 24 is set to R. That is, R=T1 / T2. The ratio R of the thickness T1 of the bottom 23 to the thickness T2 of the flange 24 is greater than 1. The ratio R is more preferably greater than 1, and more preferably greater than 2.

[0022] The upper housing 27 is in the shape of a disk. The upper housing 27 is provided to block the opening at the upper end of the cylindrical portion 22. The upper housing 27 is fitted into the upper end of the cylindrical portion 22. A through hole is formed in the center of the upper housing 27 when viewed from above, through which the rotating shaft 11 passes. The second bearing 17 is mounted in the through hole of the upper housing 27.

[0023] The first bearing 16 rotatably supports the output end 11a of the rotating shaft 11. The second bearing 17 rotatably supports the end 11b (the upper end in this embodiment) of the rotating shaft 11 opposite to the output end 11a. Therefore, the rotor 13 fixed to the rotating shaft 11 can also rotate radially inward of the stator 12.

[0024] The motor housing 21 is assembled to the housing 101. The positioning portion 25 is inserted into the opening 101a of the housing 101, and the mounting surface 21b is brought into contact with the upper surface of the housing 101. In this state, the motor housing 21 is mounted on the housing 101 by inserting the bolts 103 through the bolt holes 24a of the flange portion 24 and fastening them to the housing 101.

[0025] Here, due to manufacturing errors of the motor housing 21, deformation of the motor housing 21 during the manufacture of the rotating electrical machine 1, etc., the flange portion 24 may be deformed and the mounting surface 21b may be bent. For example, when the stator core 12a is fixed in the cylindrical portion 22 by press-fitting or burn-in, the cylindrical portion 22 may be deformed in a manner of expanding radially outward due to a load applied to the cylindrical portion 22. As the cylindrical portion 22 is deformed, when the flange portion 24 is deformed to bend downward toward the radially outward, the mounting surface 21b is also bent to bend downward toward the radially outward. When the mounting surface 21b is bent, the contact area between the mounting surface 21b and the upper surface of the housing 101 becomes smaller, and a gap is generated between the mounting surface 21b and the upper surface of the housing 101. As a result, the vibration transmitted from the rotating electrical machine 1 to the driven object 100 may increase.

[0026] By setting the ratio R of the thickness T1 of the bottom portion 23 to the thickness T2 of the flange portion 24 to be 1 or more, it is possible to suppress the transmission of vibration of the rotary electric machine 1 to the driven object 100. Figure 2 and Figure 3 State the reason.

[0027] Figure 2It is a graph showing the relationship between the vibration value of the driven object 100 based on actual measurement and the right angle index of the mounting surface 21b after the motor housing 21 is assembled to the housing 101 of the driven object 100 (hereinafter also referred to as the right angle index of the assembled mounting surface 21b) calculated using CAE analysis. The vertical axis is the vibration value of the driven object 100. The larger the vibration value of the driven object 100, the larger the vibration transmitted from the rotating electric machine 1 to the driven object 100. The horizontal axis is the right angle index of the assembled mounting surface 21b. The right angle index of the assembled mounting surface 21b refers to a value indicating the degree of curvature of the mounting surface 21b after the motor housing 21 is assembled to the housing 101 with an imaginary plane perpendicular to the axial direction as a reference. More specifically, the right angle index of the assembled mounting surface 21b refers to a value indicating the deviation of the mounting surface 21b relative to the imaginary plane. The larger the right angle index of the assembled mounting surface 21b, the more the assembled mounting surface 21b is bent downward as it moves radially outward compared to the imaginary plane. like Figure 2 As shown in FIG. 1 , when the right angle index of the assembled mounting surface 21b becomes smaller, the vibration value of the driven object 100 becomes smaller. That is, it can be seen that by reducing the right angle index of the assembled mounting surface 21b, the vibration of the rotating electric machine 1 can be suppressed from being transmitted to the driven object 100. If the right angle index of the assembled mounting surface 21b is small, the mounting surface 21b becomes a shape along an imaginary plane perpendicular to the axial direction. As a result, the contact area between the mounting surface 21b and the upper surface of the housing 101 can be increased, and as a result, the vibration of the rotating electric machine 1 can be suppressed from being transmitted to the driven object 100.

[0028] Figure 3 It is a graph showing the relationship between the right angle index of the mounting surface 21b after assembly and the ratio R of the thickness T1 of the bottom 23 to the thickness T2 of the flange 24. The vertical axis is the right angle index of the mounting surface 21b after assembly. The horizontal axis is the ratio R of the thickness T1 of the bottom 23 to the thickness T2 of the flange 24. like Figure 3As shown, when the ratio R of the thickness T1 of the bottom 23 to the thickness T2 of the flange 24 is 1 or more, the effect of reducing the right angle index of the mounting surface 21b after assembly becomes greater. If the ratio R is 1 or more, the thickness T1 of the bottom 23 becomes larger, or the thickness T2 of the flange 24 becomes smaller, compared with the case where the ratio R is less than 1. If the thickness T1 of the bottom 23 becomes larger, the rigidity of the bottom 23 is improved. By improving the rigidity of the bottom 23, it is possible to suppress the deformation of the flange 24 when the stator core 12a is fixed in the cylindrical portion 22 by press-fitting or burn-fitting. Therefore, it is possible to suppress the bending of the mounting surface 21b in the pre-assembly stage, and as a result, the right angle index of the mounting surface 21b after assembly can be reduced. In addition, if the thickness T2 of the flange 24 becomes smaller, the rigidity of the flange 24 is reduced. By reducing the rigidity of the flange 24, even if the flange 24 is deformed before assembly, the flange 24 can be deformed along the upper surface of the housing 101 by the tightening force of the bolts 103 to the housing 101. Therefore, the curvature of the mounting surface 21b can be corrected, and the right angle index of the mounting surface 21b after assembly can be reduced.

[0029] As described above, when the ratio R of the thickness T1 of the bottom portion 23 to the thickness T2 of the flange portion 24 is 1 or more, the effect of reducing the right angle index of the mounting surface 21b after assembly becomes greater, so that the vibration of the rotating electrical machine 1 can be suppressed from being transmitted to the driven object 100. In addition, when the ratio R is greater than 1, the effect of reducing the right angle index of the mounting surface 21b after assembly becomes greater, so that the vibration of the rotating electrical machine 1 can be suppressed from being transmitted to the driven object 100 more effectively. When the ratio R is greater than 2, the effect of reducing the right angle index of the mounting surface 21b after assembly becomes greater, so that the vibration of the rotating electrical machine 1 can be suppressed from being transmitted to the driven object 100 more effectively.

[0030] As described above, the rotary electric machine 1 according to the present embodiment includes the electric motor 10 and the motor housing 21 that accommodates the electric motor 10, wherein the electric motor 10 includes the rotating shaft 11, the rotor 13 fixed to the rotating shaft 11, and the stator 12 arranged outside the rotor 13. The electric motor housing 21 extends in the axial direction and includes the cylindrical portion 22 to which the stator 12 is fixed, the bottom portion 23 covering one axial end of the cylindrical portion 22, and the flange portion 24 protruding from the outer peripheral surface of the bottom portion 23. The flange portion 24 includes the mounting surface 21b that abuts against the housing 101 of the driven object 100 and is fixed to the housing 101. The ratio R of the thickness T1 of the bottom portion 23 to the thickness T2 of the flange portion 24 is 1 or more.

[0031] According to such a rotating electric machine 1, by making the ratio R equal to or greater than 1, it is possible to suppress the vibration of the rotating electric machine 1 from being transmitted to the driven object 100. Specifically, when the ratio R is equal to or greater than 1, the thickness T2 of the flange portion 24 becomes smaller, or the thickness T1 of the bottom portion 23 becomes larger, compared with the case where the ratio R is less than 1. If the thickness T1 of the bottom portion 23 becomes larger, the rigidity of the bottom portion 23 is improved. By increasing the rigidity of the bottom portion 23, it is possible to suppress the deformation of the flange portion 24 during the manufacture of the rotating electric machine 1. In addition, if the thickness T2 of the flange portion 24 becomes smaller, the rigidity of the flange portion 24 is reduced. By reducing the rigidity of the flange portion 24, even if the flange portion 24 is deformed in the motor housing 21 before being fixed to the housing 101, the flange portion 24 can be deformed along the housing 101 when the flange portion 24 is fixed to the housing 101. As a result, the curvature of the mounting surface 21b can be corrected. As described above, by setting the ratio R to 1 or more, the degree of curvature of the mounting surface 21b after the motor case 21 is assembled to the housing 101 can be reduced, and the contact area between the mounting surface 21b and the housing 101 can be increased. Therefore, the vibration of the rotating electrical machine 1 can be suppressed from being transmitted to the driven object 100. In addition, the mounting surface 21b is in contact with the housing 101. That is, without providing a damping member or the like between the motor housing 21 and the housing 101, it is possible to suppress the transmission of vibration of the rotating electric machine 1 to the driven object 100. Therefore, it is possible to suppress an increase in the number of components and an increase in the number of man-hours required to assemble the rotating electric machine 1 to the driven object 100. This can suppress an increase in the number of components and suppress transmission of vibration of the rotating electrical machine 1 to the driven object 100 .

[0032] In addition, the cylindrical portion 22, the bottom portion 23, and the flange portion 24 are integrally formed. This facilitates the manufacture of the rotating electrical machine 1 .

[0033] In addition, the stator 12 is fixed to the cylindrical portion 22 by press-fitting or shrink-fitting. Thereby, the stator 12 can be firmly fixed to the cylindrical portion 22 . In addition, when the stator 12 is fixed in the cylindrical portion 22 by press-fitting or shrink-fitting, a load is sometimes applied to the cylindrical portion 22, causing the cylindrical portion 22 to deform. Even in this case, by setting the ratio R to the above value, the deformation of the flange portion 24 can be suppressed, and the degree of bending of the mounting surface 21b after the motor housing 21 is assembled to the housing 101 can be reduced. Therefore, the vibration of the rotating electric machine 1 can be suppressed from being transmitted to the driven object 100.

[0034] Implementation method 2. Next, a rotary electric machine 1 according to Embodiment 2 will be described. The basic structure of the rotary electric machine 1 according to this embodiment is the same as that of Embodiment 1, and therefore the description will be mainly focused on the differences.

[0035] Figure 4 2 is a cross-sectional view showing a main part of the rotary electric machine 1 according to the second embodiment. Figure 4 As shown, in this embodiment, a first reinforcement portion 31 (reinforcement portion) is formed at a corner where the bottom 23 and the cylindrical portion 22 intersect, and a second reinforcement portion 32 is formed at a corner where the bottom 23 and the bearing fixing portion 23a intersect. The first reinforcement portion 31 and the second reinforcement portion 32 increase the rigidity of the bottom 23.

[0036] The first reinforcement portion 31 is a connection portion connecting the upper surface of the bottom portion 23 and the inner circumferential surface of the cylindrical portion 22. The first reinforcement portion 31 is a straight line extending radially inward as it goes downward when viewed in cross section along the central axis O. The inner surface of the first reinforcement portion 31 may be a concave curved surface. The second reinforcement portion 32 is a connection portion connecting the upper surface of the bottom portion 23 and the radial side surface of the bearing fixing portion 23a. When viewed in a cross section along the central axis O, the second reinforcement portion 32 is a straight line extending radially outward as it goes downward. The inner surface of the second reinforcement portion 32 may be a concave curved surface.

[0037] As described above, in the rotary electric machine 1 of the present embodiment, the first reinforcement portion 31 is formed at the corner where the bottom portion 23 and the cylindrical portion 22 intersect. Thus, the rigidity of the bottom 23 can be improved, and deformation of the flange 24 during the manufacture of the rotating electrical machine 1 can be more effectively suppressed. Therefore, the degree of bending of the mounting surface 21b after the motor housing 21 is assembled to the housing 101 can be reduced, and the transmission of vibration of the rotating electrical machine 1 to the driven object 100 can be more effectively suppressed.

[0038] Implementation method 3. Next, a rotary electric machine 1 according to Embodiment 3 will be described. Since the basic structure of the rotary electric machine 1 according to this embodiment is the same as that of Embodiment 1, the description will be mainly focused on the differences.

[0039] Figure 5 It is a cross-sectional view showing a main part of a rotating electrical machine 1 according to a third embodiment. Figure 6 This is a diagram showing the main parts of the rotary electric machine 1 according to the third embodiment as viewed from below. Figure 5 and Figure 6As shown, in this embodiment, the mounting portion 21a is formed with a groove portion 34. The groove portion 34 is arranged between the bolt hole 24a of the flange portion 24 and the positioning portion 25. The groove portion 34 is recessed upward from the mounting surface 21b. That is, the groove portion 34 opens toward the housing 101. The groove portion 34 is arranged at a position overlapping with the flange portion 24 in the radial direction. By providing the groove portion 34, the rigidity of the mounting portion 21a can be reduced, and when the flange portion 24 is fixed to the housing 101, it is easy to deform the flange portion 24 along the housing 101.

[0040] As described above, in the rotating electrical machine 1 according to the present embodiment, the groove portion 34 opening toward the housing 101 is formed in the portion between the positioning portion 25 and the bolt hole 24 a of the motor case 21 . Thus, when the flange 24 is fixed to the housing 101, the flange 24 can be easily deformed along the housing 101, and the curvature of the mounting surface 21b can be corrected more effectively. Therefore, the curvature of the mounting surface 21b after the motor housing 21 is assembled to the housing 101 can be reduced, and the vibration of the rotating electric machine 1 can be more effectively suppressed from being transmitted to the driven object 100.

[0041] A variation of implementation example 3. Figure 7 This is a diagram showing the main parts of the rotating electrical machine 1 according to a modified example of the third embodiment as viewed from below. Figure 7 As shown, the groove 34 may be provided over the entire circumference of the motor housing 21. In this case, when the flange 24 is fixed to the housing 101, it is easier to deform the flange 24 along the housing 101. Therefore, the vibration of the rotating electric machine 1 can be more effectively suppressed from being transmitted to the driven object 100.

[0042] Implementation method 4. Next, a rotating electrical machine 1A according to Embodiment 4 will be described. Since the basic structure of the rotating electrical machine 1A according to the present embodiment is the same as that of Embodiment 1, the description will be mainly focused on the differences.

[0043] Figure 8 1 is a schematic cross-sectional view of a rotating electrical machine 1A according to Embodiment 4. In the present embodiment, the motor 10 of the rotating electrical machine 1A is a permanent magnet synchronous motor. That is, in the present embodiment, the rotor 13 includes a rotor core 13a and a plurality of permanent magnets 13b. The rotor core 13a is cylindrical. The rotor core 13a is disposed around the rotating shaft 11 and is fixed to the rotating shaft 11. A plurality of permanent magnets 13b are disposed on the outer peripheral surface of the rotor core 13a. The plurality of permanent magnets 13b are arranged so that the polarities (S poles and N poles) of the outer peripheral surface of the rotor 13 alternate with each other in the circumferential direction. In addition, the stator core 12a of the stator 12 has a core back formed in an annular shape and a plurality of teeth protruding radially inward from the core back. The plurality of coils 12b are formed by winding the windings on each of the plurality of teeth in a concentrated manner. The plurality of coils 12b are formed by winding the windings on the plurality of teeth in a distributed manner.

[0044] Fig. 9 It is a graph showing the values ​​of short-section winding coefficient, distributed winding coefficient and winding coefficient in permanent magnet synchronous motors of 8 poles and 9 slots, 10 poles and 9 slots, 10 poles and 12 slots and 14 poles and 12 slots. Here, the permanent magnet synchronous motor of 8 poles and 9 slots refers to a permanent magnet synchronous motor in which the number of poles of the permanent magnet 13b is 8 and the number of teeth of the stator core 12a is 9. In addition, a permanent magnet synchronous motor in which the number of poles of the permanent magnet 13b and the number of teeth of the stator core 12a are set to integer multiples of the number of poles and the number of teeth of the 8 poles and 9 slots is called a permanent magnet synchronous motor of the 8 poles and 9 slots series. The winding coefficient in the permanent magnet synchronous motor of the 8 poles and 9 slots series is the same value as the winding coefficient of the permanent magnet synchronous motor of 8 poles and 9 slots. 10 poles and 9 slots, 10 poles and 12 slots and 14 poles and 12 slots are also the same as 8 poles and 9 slots.

[0045] like Fig. 9 As shown, when the motor 10 of the rotating electrical machine 1A is a permanent magnet synchronous motor of 8-pole 9-slot series, 10-pole 9-slot series, 10-pole 12-slot series, or 14-pole 12-slot series, the winding coefficient relative to the fundamental wave is high, and the output torque of the rotating electrical machine 1A can be increased. Therefore, a low-cost and high-performance rotating electrical machine 1A can be provided. On the other hand, in this case, since electromagnetic force is generated to deform the rotor core 13a into an ellipse, the vibration of the rotating electrical machine 1A may increase. However, even in this case, by setting the ratio R to the above value, the vibration of the rotating electrical machine 1A can be suppressed from being transmitted to the driven object 100.

[0046] Implementation method 5. Next, a rotary electric machine 1B according to Embodiment 5 will be described. Since the basic structure of the rotary electric machine 1B according to this embodiment is the same as that of Embodiment 4, the description will be mainly focused on the differences.

[0047] Fig.10 FIG. 1 is a schematic cross-sectional view of a rotating electrical machine 1B according to Embodiment 5. Fig.10 As shown, in the present embodiment, the rotary electric machine 1B further includes a control device 41 and a connector 44. Moreover, similarly to the fourth embodiment, the electric motor 10 of the rotary electric machine 1B is a permanent magnet synchronous motor.

[0048] The control device 41 is arranged above the motor 10. That is, the control device 41 is arranged on the side opposite to the bottom 23 in the axial direction relative to the motor 10. The control device 41 includes a circuit substrate 42 and an electronic circuit 43 provided on the circuit substrate 42. The circuit substrate 42 is, for example, a multilayer printed substrate stacked with a plurality of insulating layers and a plurality of conductor layers. The electronic circuit 43 includes an inverter circuit for driving the motor 10, a control circuit for controlling the inverter circuit, and the like. Electronic components such as power semiconductor elements forming the inverter circuit and a CPU performing calculation processing are mounted on the circuit substrate 42. The electronic circuit 43 is composed of these electronic components and a circuit pattern formed on the circuit substrate 42. The circuit substrate 42 is covered from above by a cover 46.

[0049] In this embodiment, the motor housing 21 further includes a protrusion 29 protruding radially outward from the upper end of the cylindrical portion 22. The circuit board 42 is supported by the upper housing 27 and the protrusion 29. The circuit board 42 is fixed to the upper housing 27 and the protrusion 29 by screws (not shown).

[0050] The connector 44 is provided on the lower surface of the protrusion 29. The connector 44 is used to connect the rotating electrical machine 1 to an external power source and an external sensor, etc. The connector 44 is electrically connected to the electronic circuit 43. The power of the external power source and the signal of the external sensor are transmitted to the electronic circuit 43 via the connector 44.

[0051] As described above, the rotary electric machine 1B according to the present embodiment further includes the control device 41 for controlling the electric motor 10. The control device 41 is disposed on the side of the electric motor 10 opposite to the bottom portion 23 in the axial direction. Thus, in the rotating electrical machine 1B, the motor 10 and the control device 41 can be integrally provided. In addition, since the control device 41 is arranged on the side opposite to the bottom 23 in the axial direction with respect to the motor 10, it is possible to suppress the vibration of the motor 10 from being transmitted to the control device 41, compared with the case where the control device 41 is arranged on the bottom 23 side (i.e., the output side of the motor 10).

[0052] Implementation method 6. The rotating electrical machines 1 , 1A, and 1B according to the above-described embodiments are suitably applied to an electric power steering device mounted on a vehicle. As a sixth embodiment, an electric power steering device 200 including the rotating electrical machine 1 will be described.

[0053] Fig.11 FIG. 2 is a perspective view of an electric power steering device 200 according to Embodiment 6. Fig.11As shown, the electric power steering device 200 according to the present embodiment includes a rotary electric machine 1 , a gear mechanism 201 , a steering mechanism 202 , wheels 203 , a steering wheel 204 , a steering shaft 205 , and a torque sensor 206 .

[0054] The electric motor 10 of the rotary electric machine 1 is used as an assisting electric motor that transmits the driving force generated by the electric motor 10 to the steering mechanism 202 as a steering assist force. The gear mechanism 201 connects the rotating shaft 11 of the rotary electric machine 1 and the steering shaft 205. The gear mechanism 201 transmits the driving force generated by the electric motor 10 to the steering mechanism 202 of the vehicle. The gear mechanism 201 corresponds to the driven object 100 in the above-described embodiment. The steering wheel 204 is operated by a driver who drives the vehicle, and can be rotated left or right. The steering shaft 205 is connected to the steering wheel 204 . The steering shaft 205 transmits the steering torque based on the steering wheel 204 to the steering mechanism 202 connected to the wheels 203 . The torque sensor 206 is mounted on the steering shaft 205 . The torque sensor 206 detects the steering torque based on the steering wheel 204 .

[0055] When the vibration of the rotating electric machine 1 is transmitted to the gear mechanism 201 as the driven object 100, the gear mechanism 201 vibrates, generating an abnormal sound. However, by using the rotating electric machine 1 involved in the above-mentioned embodiment, the vibration of the rotating electric machine 1 can be suppressed from being transmitted to the gear mechanism 201, so the vibration of the gear mechanism 201 and the generation of abnormal sound can be suppressed.

[0056] The various embodiments may be combined, or the various embodiments may be appropriately modified or omitted.

[0057] Fig.12 FIG. 1 is a schematic cross-sectional view of a rotating electrical machine 1 according to a modified example of the first embodiment. Fig.12As shown, the motor housing 21 may also include a first frame portion 51 forming the cylindrical portion 22, and a second frame portion 52 forming the bottom portion 23, the plurality of flange portions 24, and the positioning portion 25. That is, the cylindrical portion 22, the bottom portion 23, the plurality of flange portions 24, and the positioning portion 25 may also be formed by other components. The first frame portion 51 is formed with a fitting recess 51a. The fitting recess 51a is formed on the inner circumferential surface of the lower end portion of the cylindrical portion 22. The second frame portion 52 is formed with a fitting protrusion 52a. The fitting protrusion 52a is formed to protrude upward from the upper surface of the outer circumference of the bottom portion 23. By fitting the fitting protrusion 52a into the fitting recess 51a, the first frame portion 51 and the second frame portion 52 are assembled to form the motor housing 21. In order to firmly fix the first frame portion 51 and the second frame portion 52, it is preferable to press the fitting protrusion 52a into the fitting recess 51a. In addition, the first frame portion 51 and the second frame portion 52 may also be fixed by screw fastening.

[0058] In the electric power steering device 200 according to the sixth embodiment, any of the rotating electrical machines 1 according to the first to third embodiments, the rotating electrical machine 1A according to the fourth embodiment, and the rotating electrical machine 1B according to the fifth embodiment may be used. Description of symbols

[0059] 1, 1A, 1B Rotating electrical machines 10. Electric Motor 11 Rotation axis 12 Stator 13 Rotor 13a Rotor core 13b Permanent magnet 21 Motor housing 21a Installation 21b Mounting surface 22 Cylinder 23 Bottom 24 Flange 24a Bolt hole 25 Positioning unit 31 first reinforcement part (reinforcement part) 34 Groove 41 Control device 44 Connectors 100 drive objects 200 Electric power steering.

Claims

1. A rotating electric machine, the rotating electric machine being mounted on a driven object, characterized in that: include: an electric motor including a rotating shaft, a rotor fixed to the rotating shaft, and a stator arranged outside the rotor; and a motor housing, the motor housing housing the motor, The motor housing has: a cylindrical portion extending along the axial direction of the rotating shaft and having the stator fixed thereto; a bottom portion covering one end portion of the cylindrical portion in the axial direction; and a flange portion protruding from an outer peripheral surface of the bottom portion, The flange portion has a mounting surface that abuts against a housing of the driven object and is fixed to the housing. A ratio of the thickness of the bottom portion to the thickness of the flange portion is 1 or more.

2. The rotating electrical machine according to claim 1, characterized in that The cylindrical portion, the bottom portion, and the flange portion are integrally formed.

3. The rotating electrical machine according to claim 1 or 2, characterized in that: The stator is fixed to the cylindrical portion by press-fitting or shrink-fitting.

4. The rotating electrical machine according to any one of claims 1 to 3, characterized in that: A reinforcement portion is formed at a corner where the bottom portion intersects the cylindrical portion.

5. The rotating electrical machine according to any one of claims 1 to 4, characterized in that The motor housing further includes a positioning portion that protrudes from the bottom toward one side in the axial direction and is inserted into an opening formed on the housing of the driven object. The flange portion has a bolt hole, through which a bolt fastened to the housing is inserted. A groove portion opening toward the housing is formed in a portion of the motor case between the positioning portion and the bolt hole.

6. The rotating electrical machine according to claim 5, characterized in that The groove portion is provided in the motor case over the entire circumference of the rotating shaft.

7. The rotating electrical machine according to any one of claims 1 to 6, characterized in that: The electric motor is a permanent magnet synchronous motor including a rotor core in which the rotor is fixed to the rotating shaft, and a plurality of permanent magnets provided on an outer peripheral surface of the rotor core.

8. The rotating electrical machine according to claim 7, characterized in that The motor is a permanent magnet synchronous motor of an 8-pole 9-slot series, a 10-pole 9-slot series, a 10-pole 12-slot series or a 14-pole 12-slot series.

9. The rotating electrical machine according to any one of claims 1 to 8, characterized in that Also includes a control device for controlling the motor, The control device is arranged on the side opposite to the bottom portion in the axial direction with respect to the electric motor.

10. The rotating electrical machine according to any one of claims 1 to 9, characterized in that The electric motor is used as an assisting electric motor for an electric power steering device.

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