Rotating electric machines

Abstract

A rotating electric machine capable of suppressing the generation of vibration and noise is provided. [Solution] The rotating electric machine includes a rotor, a stator, a first cover 6, and a second cover 7. The stator surrounds the rotor in an annular shape centered on the rotor's rotational axis. The first cover covers one end face of the stator in the rotational axis direction. The second cover covers the other end face of the stator opposite the one end face. The first and second covers have a plurality of seating surfaces 63 spaced apart circumferentially around their ends, which protrude in a direction parallel to the rotational axis direction from the peripheral edge opposite the peripheral edge of the end face of the stator, and serve as seating surfaces for the stator. The first and second covers are fastened to each other with bolts, sandwiching the stator between them.

Description

[Technical Field]

[0001] The disclosed embodiments relate to a rotating electric machine. [Background technology]

[0002] There is a rotating electric machine that includes a stator that surrounds a rotor in an annular shape centered on the rotor's rotation axis, a first cover that covers the stator from one end face to a part of its side face, and a second cover that covers the stator from the other end face to a part of its side face. The first cover and the second cover are fastened together with bolts while sandwiching the stator (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-038480 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a rotating electric machine in which the first cover and the second cover are fastened with bolts, vibrations from the stator can be transmitted to the first cover and the second cover, and then from the first cover and the second cover to other components, causing vibrations and noise.

[0005] One aspect of an embodiment has been made in view of the above, and aims to provide a rotating electric machine that can suppress the generation of vibration and noise. [Means for solving the problem]

[0006] According to one aspect of the embodiment, a rotating electric machine includes a rotor, a stator, a first cover, and a second cover. The stator surrounds the rotor in an annular shape centered on a rotational axis of the rotor. The first cover covers one end face of the stator in the rotational axis direction. The second cover covers the other end face of the stator opposite the one end face. The first cover and the second cover have a plurality of bearing surface portions that protrude in a direction parallel to the rotational axis direction from peripheral edges of the stator that face the end face, and are spaced apart in the circumferential direction of the ends to form bearing surfaces for the stator. The first cover and the second cover are fastened to each other with bolts sandwiching the stator. [Effects of the Invention]

[0007] In one aspect of the embodiment, the rotating electric machine has contact portions between the first cover and the second cover and the stator that are limited to seating portions spaced apart circumferentially, making it difficult for vibrations of the stator to be transmitted to the first cover and the second cover, thereby suppressing the generation of vibrations and noise. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of a rotating electrical machine 2 according to an embodiment. [Figure 2] FIG. 2 is an enlarged view showing the portion enclosed by the dotted line in FIG. [Figure 3] FIG. 3 is a plan view of the first cover according to the embodiment as viewed from the teeth side. [Figure 4] FIG. 4 is a partial cross-sectional view showing a fastening portion of the first cover, the second cover, and the stator according to the embodiment. [Figure 5] FIG. 5 is a partial cross-sectional view showing contact portions between the first cover and the second cover and the stator according to the embodiment. [Figure 6] FIG. 6 is a partial cross-sectional view showing non-contact portions between the first cover and the second cover and the stator according to the embodiment. [Figure 7] FIG. 7 is a perspective view of the seat portion according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of a rotating electric machine will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below. The rotating electric machine according to the embodiment is mounted, for example, on the hub of an electrically assisted bicycle and assists the human-powered driving force by applying driving force to the wheels of a human-powered vehicle. In the following description, identical components of the rotating electric machine will be designated by the same reference numerals, and redundant description will be omitted.

[0010] The rotating electric machine according to the embodiment may be provided at a location other than the hub of a human-powered vehicle to assist the human-powered driving force. The rotating electric machine according to the embodiment may also be provided in any type of mobility, such as an electric kick scooter.

[0011] Fig. 1 is a cross-sectional explanatory view of a rotating electric machine 2 according to an embodiment. Fig. 2 is a plan view of a first cover according to an embodiment as viewed from the teeth side. Fig. 3 is an enlarged explanatory view showing a portion within a dotted line frame shown in Fig. 1. Fig. 4 is a partial cross-sectional view showing a fastening portion of a first cover 6, a second cover 7, and a stator 5 according to an embodiment.

[0012] Fig. 5 is a partial cross-sectional view showing contact portions between the first cover 6 and the second cover 7 and the stator 5 according to the embodiment. Fig. 6 is a partial cross-sectional view showing non-contact portions between the first cover 6 and the second cover 7 and the stator 5 according to the embodiment. Fig. 7 is a perspective view of a seat portion 63 according to the embodiment.

[0013] 1 shows a cross section of the rotating electric machine 2 taken along a line along a rotation axis 3 of the rotating electric machine 2. As shown in FIG. 1, the rotating electric machine 2 includes a rotor 4, a stator 5, a first cover 6, a second cover 7, and a housing 8.

[0014] The rotor 4 rotates integrally with the rotating shaft 3. The rotating shaft 3 serves as the axle of the power-assisted bicycle. The stator 5 is disposed so as to surround the rotor 4 in an annular shape, with the rotating shaft 3 of the rotor 4 at the center.

[0015] The first cover 6 is provided to cover one end face of the stator 5 in the extension direction of the rotary shaft 3. The second cover 7 is provided to cover the other end face of the stator 5 opposite to the one end face covered by the first cover 6.

[0016] As shown in Figures 2 and 3, the first cover 6 includes a disk portion 61 that faces the end face of the stator 5 in a direction parallel to the extension direction of the rotating shaft 3, and an annular portion 62 that extends from the peripheral portion of the disk portion 61 toward the peripheral portion of the stator 5 in a direction parallel to the extension direction of the rotating shaft 3.

[0017] The first cover 6 is provided with a plurality of seating surfaces 63 which protrude from a peripheral portion (annular portion 62) facing the peripheral portion 52 of the end face 51 of the stator 5 in a direction parallel to the extension direction of the rotating shaft 3 (the direction of the dashed arrow in Figure 3) and serve as seating surfaces for the stator 5.

[0018] The seating surfaces 63 are provided at intervals in the circumferential direction of the peripheral edge portion (annular portion 62) of the first cover 6. The second cover 7 has the same configuration as the first cover 6. Therefore, a redundant description of the second cover 7 will be omitted.

[0019] As shown in FIG. 4, the first cover 6 and the second cover 7 are fastened to each other with bolts 9 in a state in which the stator 5 is sandwiched between the multiple seating portions 63 provided on the first cover 6 and the multiple seating portions 63 provided on the second cover 7.

[0020] As a result, as shown by the dotted ovals in Figure 5, the first cover 6 and the second cover 7 come into contact with the stator 5 where the seating surface portions 63 are provided, but as shown by the dotted ovals in Figure 6, they do not come into contact with the stator 5 where the seating surface portions 63 are not provided.

[0021] As described above, in the rotating electric machine 2 according to this embodiment, the contact portions of the first cover 6 and the second cover 7 with the stator 5 are limited to the seating surface portions 63 that are spaced apart in the circumferential direction. Therefore, in the rotating electric machine 2, vibrations of the stator 5 are less likely to be transmitted to the first cover 6 and the second cover 7, and therefore vibrations and noise caused by the first cover 6, the second cover 7, and other members that come into contact with these members can be suppressed.

[0022] 2, the circumferential length of the seating surface portions 63 in the annular portion 62 is smaller than the circumferential distance between circumferentially adjacent seating surface portions 63. Therefore, the area of ​​the portion of the annular portion 62 where the first cover 6 and the stator 5 contact each other is smaller than the area of ​​the portion of the annular portion 62 where the first cover 6 and the stator 5 do not contact each other.

[0023] Furthermore, as with the first cover 6, the area of ​​the second cover 7 where the second cover 7 and the stator 5 contact each other in the annular portion 62 is smaller than the area of ​​the part of the annular portion 62 where the second cover 7 and the stator 5 do not contact each other.

[0024] As a result, the contact area between the first cover 6 and the second cover 7 and the stator 5 of the rotating electric machine 2 is smaller, making it less likely that vibrations from the stator 5 will be transmitted to the first cover 6 and the second cover 7, thereby suppressing the generation of vibrations and noise.

[0025] 2 and 7, the first cover 6 has through holes 10 that penetrate through a plurality of locations in the annular portion 62 that forms the peripheral edge in a direction parallel to the extension direction of the rotary shaft 3, and into which bolts 9 are inserted. The second cover 7 also has through holes 10 that have the same configuration as the first cover 6.

[0026] The seating surface portions 63 are provided at positions including the through holes 10 in the annular portion 62 that forms the periphery of the first cover 6. Similarly, the seating surface portions 63 of the second cover 7 are provided at positions including the through holes 10. As a result, the rotating electric machine 2 is fastened with the bolts 9 at the seating surface portions 63 where the first cover 6 and the second cover 7 come into contact with the stator 5, thereby improving the fastening strength of the bolts 9.

[0027] 4, the stator 5 includes an annular core back 53 and a recess 54 recessed from the side surface of the core back 53 toward the rotating shaft 3. On the other hand, the first cover 6 includes a protrusion 64 that protrudes in a direction parallel to the extension direction of the rotating shaft 3 from a position where the through hole 10 is provided in the annular portion 62 that forms the peripheral edge, and is fitted into the recess 54, as shown in FIGS. 4 and 7. The second cover 7 also includes a protrusion 64 that is fitted into the recess 54, similar to the first cover 6.

[0028] 7, the circumferential length of the annular portion 62 of the seating surface portion 63 is greater than the circumferential length of the protruding portion 64. In this way, the seating surface portion 63 has an area of ​​at least a certain size as a portion that comes into contact with the end face of the stator 5. This improves the mechanical strength of the seating surface portion 63, and therefore, when the seating surface portion 63 is fastened to the stator 5 by the bolts 9, it is possible to suppress crushing, breakage, and rattle.

[0029] 2, the stator 5 includes a plurality of teeth 55 extending from the inner peripheral surface of the core back 53 toward the rotating shaft 3. Note that Fig. 2 shows only one tooth 55, and the other teeth 55 are not shown.

[0030] On the other hand, the protrusions 64 and the through holes 10 of the first cover 6 and the second cover 7 are provided outside the teeth 55. The outer side surfaces 56 of the teeth 55 have an arc shape that follows part of the side surface of the bolt 9 (see FIG. 4) that is inserted into the through hole 10.

[0031] This eliminates the need for punching or other processes for the through holes, and allows the teeth 55 to be formed more easily than when, for example, through holes are formed for inserting the bolts 9. Also, the length of the portion extending from the inner peripheral surface of the core back 53 toward the rotating shaft 3, i.e., the length of the portion around which the coil wire is wound, can be increased.

[0032] Furthermore, since the teeth 55 contact only a portion (for example, 2 / 3 of the circumference) of the side surface of the bolt 9 rather than the entire circumference, vibrations of the teeth 55 are less likely to be transmitted to the first cover 6 and the second cover 7 via the bolt 9 compared to when the teeth 55 contact the entire circumference of the side surface of the bolt 9. This allows the rotating electric machine 2 to further suppress the generation of vibrations and noise.

[0033] As shown in FIG. 2, the fastening positions of the bolts 9 on the first cover 6 and the second cover 7 (the dotted oval locations shown in FIG. 4) are perpendicular to the extension direction of the rotating shaft 3 (the direction of the dashed-dotted arrow) and are symmetrical with respect to the line (the dashed-dotted arrow) passing through the center of the stator 5.

[0034] That is, when the rotating electric machine 2 is mounted on the hub of a bicycle, the two fastening positions with one bolt 9 are symmetrical with respect to the center in the width direction of the wheel when the bicycle is viewed from the front.

[0035] As a result, when the rotor 4 of the rotating electric machine 2 rotates, the vibration of the stator 5 is transmitted evenly to the first cover 6 and the second cover 7, so that distortion of the first cover 6 and the second cover 7 is uniform and noise generation is suppressed.

[0036] The present technology can be configured as follows. (1) A rotor, a stator that annularly surrounds the rotor around a rotation axis of the rotor; a first cover that covers one end face of the stator in the extension direction of the rotation shaft; a second cover that covers the other end face of the stator opposite to the one end face, The first cover and the second cover are A plurality of seating surfaces that protrude from a peripheral edge portion of the stator that faces a peripheral edge portion of the end face in a direction parallel to the extension direction of the rotation shaft and serve as seating surfaces of the stator are provided at intervals in the circumferential direction of the peripheral edge portion, and the plurality of seating surfaces provided on the first cover and the plurality of seating surfaces provided on the second cover are fastened to each other with bolts while sandwiching the stator. Rotating electric motor. (2) The seat portion is The length in the circumferential direction is smaller than the distance between the adjacent seat portions in the circumferential direction. The rotating electric machine according to (1) above. (3) The first cover and the second cover are through holes into which the bolts are inserted, the through holes penetrating a plurality of locations in the peripheral edge portion in a direction parallel to the extension direction of the rotation shaft; The seat portion is The through hole is provided at a position on the peripheral edge portion. The rotating electric machine according to (1) or (2). (4) The stator includes: An annular core back; a recess recessed from a side surface of the core back toward the rotation shaft, The first cover and the second cover are a protrusion that protrudes from a position where the through hole is provided in the peripheral edge portion in a direction parallel to the extension direction of the rotation shaft and is fitted into the recess, The seat portion is The length in the circumferential direction is greater than the length in the circumferential direction of the protrusion. The rotating electric machine according to (3) above. (5) The stator includes: a plurality of teeth extending from an inner peripheral surface of the core back in a direction toward the rotation shaft, the protrusions and the through holes are provided on the outer sides of the teeth, The outer side surface of the tooth has an arc shape that follows a part of the side surface of the bolt that is inserted into the through hole. The rotating electric machine according to (4) above.

[0037] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0038] 2 Rotating electric machines 3 Rotation Axis 4 rotors 5 Stator 6 First Cover 7 Second Cover 8. Housing 9 volts 10 through holes 51 End face 52 Periphery 53 Coreback 54 Recess 55 Teeth 56 Side 61 Disc Section 62 Annular section 63 Seat part 64 Convex part

Claims

1. A rotor, a stator that annularly surrounds the rotor around a rotation axis of the rotor; a first cover that covers one end surface of the stator in an extension direction of the rotation shaft; a second cover covering the other end face of the stator opposite to the one end face, The first cover and the second cover are A plurality of seating surfaces that protrude from a peripheral edge portion of the stator that faces a peripheral edge portion of the end face in a direction parallel to the extension direction of the rotation shaft and serve as seating surfaces of the stator are provided at intervals in the circumferential direction of the peripheral edge portion, and the plurality of seating surfaces provided on the first cover and the plurality of seating surfaces provided on the second cover are fastened to each other with bolts while sandwiching the stator. Rotating electric motor.

2. The seat portion is The length in the circumferential direction is smaller than the distance between the adjacent seat portions in the circumferential direction. The rotating electric machine according to claim 1 .

3. The first cover and the second cover are through holes into which the bolts are inserted, the through holes penetrating a plurality of locations in the peripheral edge portion in a direction parallel to the extension direction of the rotation shaft; The seat portion is The through hole is provided at a position on the peripheral edge portion. The rotating electric machine according to claim 1 .

4. The stator includes: An annular core back; a recess recessed from a side surface of the core back toward the rotation shaft, The first cover and the second cover are a protrusion that protrudes from a position where the through hole is provided in the peripheral edge portion in a direction parallel to the extension direction of the rotation shaft and is fitted into the recess, The seat portion is The length in the circumferential direction is greater than the length in the circumferential direction of the protrusion. The rotating electric machine according to claim 3 .

5. The stator includes: a plurality of teeth extending from an inner peripheral surface of the core back in a direction toward the rotation shaft, the protrusions and the through holes are provided on the outer sides of the teeth, The outer side surface of the tooth has an arc shape that follows a part of the side surface of the bolt that is inserted into the through hole. The rotating electric machine according to claim 4.

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