Patent Application
20190252937
The present disclosure relates to a stator and a motor.
A brushless motor equipped with a columnar rotor and a stator having, at the center, space in which the rotor is placed is disclosed in Japanese Unexamined Patent Application Publication No. 2015-211587. The stator has an annular stator core and first to twelfth teeth that are sequentially provided in the circumferential direction on the inner circumferential side of the stator core. A conductor is wound on each of the first to twelfth teeth, forming first to twelfth coils. The first to twelfth coils each include a coil forming a U-phase, a coil forming V-phase, and a coil forming a W-phase.
Each phase has a connecting wire that connects two coils in the same phase together. The connecting wire in each phase is placed at the outer edge of one of both end faces of the stator core in the axial direction. The connecting wires in all phases are placed so as not to mutually intersect. Part of a plurality of connecting wires is superimposed when viewed from the axial direction. However, the connecting wires in all phases do not come into mutual contact by being placed at different positions in the axial direction.
As a method of avoiding the mutual contacts of the connecting wires, it is effective to change the height positions of the connecting wires in the axial direction as in Japanese Unexamined Patent Application Publication No. 2015-211587. In this method, however, there is the possibility that the thickness of the motor in the axial direction is increased. Moreover, if an insulating member such as an insulating tube is placed around the connecting wires to avoid the mutual contact of the connecting wires, there is the possibility that work loads in the manufacturing of the stator are increased.
A stator according to an exemplary embodiment of the present disclosure is an annular stator, the center of which is a central axis extending in the up-and-down direction. The stator includes a stator core that includes a plurality of teeth arrayed in the circumferential direction. The stator also includes a plurality of coils with a conducting wire wound on each of the plurality of teeth. The plurality of coils include coil groups in three phases, which are a U-phase, a V-phase, and a W-phase, and also include connecting wires that relay the coils in the same phase. On each of the upper and lower sides of the stator core, the connecting wire in one phase is located in an area distant from the connecting wires in the other phases in the circumferential direction.
A motor according to an exemplary embodiment of the present disclosure includes an exemplary stator, described above, in the present disclosure and a rotor opposing the stator.
The above and other elements, features, steps, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.
Exemplary embodiments of the present disclosure will be described in detail while the drawings are referenced. Incidentally, in this description, the direction in which the central axis A of the motor illustrated in
The stator 10 is annularly disposed around the central axis A extending in the up-and-down direction. The stator 10 has a stator core 11 and a plurality of coils C.
As illustrated in
In this embodiment, the stator core 11 has first to twelfth teeth T1 to T12 that are sequentially placed in the circumferential direction. That is, the number of teeth T is 12. The first to twelfth teeth T1 to T12 are placed at equal intervals in the circumferential direction. The stator 10 has first to twelfth coils C1 to C12 with a conducting wire wound on each of the first to twelfth teeth T1 to T12. That is, the number of coils C is 12.
The rotor 20 faces the stator 10. To be more specific, the outer circumferential surface of the rotor 20 faces the inner circumferential surface of the stator 10. The rotor 20 rotates around the central axis A. The rotor 20 has a columnar shaft 21, a cylindrical rotor core 22, and a magnet 23. The shaft 21 extends along the central axis A. The rotor core 22 is placed on the outer side of the shaft 21 in the radial direction. The rotor core 22 is formed by, for example, laminating a plurality of magnetic steel plates. The magnet 23 is fixed to the outer circumferential surface of the rotor core 22. The shaft 21 is rotatably supported by bearings 24 placed on the upper and lower sides of the rotor core 22.
The bus bar 30 is electrically connected to the rotor 20. Lead wires led from the coils C are connected to the bus bar 30. In this embodiment, by insert molding, for example, the bus bar 30 is held by an insulative resin. A bus bar unit 31 formed from the insulative resin and bus bar 30 is provided in a substantially circular ring shape and is placed on the upper side of the stator 10. By providing the bus bar 30, it is possible to prevent connection processing on lead wires led from the coils C from becoming complex. Details of a relationship between the coils C and the bus bar 30 will be described later.
The motor 1 further has a housing 40, which is substantially cylindrical, extends in the axial direction, and has a bottom. The housing 40 is placed on the more outer side in the radial directions than is the stator 10 and encloses the stator 10. Of the two bearings 24, the bearing 24 on the lower side is fixed to the central portion of the bottom wall of the housing 40. The bearing 24 on the upper side is fixed to the central portion of an inner lid 41 placed in the housing 40.
Incidentally, a plunger 50 formed from a gear is placed on the inner lid 41. The rotational motion of the motor 1 is converted to linear motion by the plunger 50, which presses a piston (not illustrated), generating a negative pressure needed for braking.
In the stator 10, the coils C in three phases are placed in the circumferential direction in the order of the U-phase, V-phase and W-phase. Each of the coil groups UG, VG, and WG in three phases has coil pairs CS, in each of which two coils C are connected in series. In this embodiment, the stator 10 has six coil pairs CS. Each of the coil groups UG, VG, and WG has two coil pairs CS. Each of the coil groups UG, VG, and WG in three phases has a structure in which two coil pairs CS are connected in parallel. Since, in the structure in this embodiment, the number of coils C is 12 and the coils C are repeatedly placed in the circumferential direction in the order of the U-phase, V-phase and W-phase, the magnetism of the motor 1 can be well-balanced and the efficient motor 1 can be manufactured.
To be more specific, in the U-phase coil group UG, the first coil C1 and fourth coil C4 form a coil pair CS and the seventh coil C7 and tenth coil C10 form a coil pair CS. In these two coil pairs CS, the first coil C1 and tenth coil C10 are electrically connected in parallel and the fourth coil C4 and seventh coil C7 are electrically connected in parallel.
In the V-phase coil group VG, the second coil C2, and eleventh coil C11 form a coil pair CS and the fifth coil C5 and eighth coil C8 form a coil pair CS. In these two coil pairs CS, the second coil C2, and fifth coil C5 are electrically connected in parallel and the eighth coil C8 and eleventh coil C11 are electrically connected in parallel.
In the W-phase coil group WG, the third coil C3 and sixth coil C6 form a coil pair CS and the ninth coil C9 and twelfth coil C12 form a coil pair CS. In these two coil pairs CS, the third coil C3 and twelfth coil C12 are electrically connected in parallel and the sixth coil C6 and ninth coil C9 are electrically connected in parallel.
A pair of the first coil C1 and fourth coil C4, which are connected in series, has a first U-phase connecting wire CW_U1, a first lead wire L1, and a fourth lead wire L4. The first U-phase connecting wire CW_U1 is placed on one of the upper and lower sides of the stator core 11 and relays both coils C1 and C4. In this embodiment, the first U-phase connecting wire CW_U1 is placed on the lower side of the stator core 11. The first U-phase connecting wire CW_U1 is placed along, for example, the outer circumferential surface of the insulator 12 in the radial direction. The first U-phase connecting wire CW_U1 may be supported by part of the insulator 12. The first lead wire L1 is led from the first coil C1. The fourth lead wire L4 is led from the fourth coil C4.
A pair of the seventh coil C7 and tenth coil C10, which are connected in series, has a second U-phase connecting wire CW_U2, a seventh lead wire L7, and a tenth lead wire L10. The second U-phase connecting wire CW_U2 is placed on the other of the upper and lower sides of the stator core 11 and relays both coils C7 and C10. In this embodiment, the second U-phase connecting wire CW_U2 is placed on the upper side of the stator core 11. The second U-phase connecting wire CW_U2 is placed along, for example, the outer circumferential surface of the insulator 12 in the radial direction. The second U-phase connecting wire CW_U2 may be supported by part of the insulator 12. The seventh lead wire L7 is led from the seventh coil C7. The tenth lead wire L10 is led from the tenth coil C10.
A pair of the fifth coil C5 and eighth coil C8, which are connected in series, has a first V-phase connecting wire CW_V1, a fifth lead wire L5, and an eighth lead wire L8. The first V-phase connecting wire CW_V1 is placed on one of the upper and lower sides of the stator core 11 and relays both coils C5 and C8. In this embodiment, the first V-phase connecting wire CW_V1 is placed on the lower side of the stator core 11. The first V-phase connecting wire CW_V1 is placed along, for example, the outer circumferential surface of the insulator 12 in the radial direction. The first V-phase connecting wire CW_V1 may be supported by part of the insulator 12. The fifth lead wire L5 is led from the fifth coil C5. The eighth lead wire L8 is led from the eighth coil C8.
A pair of the second coil C2, and eleventh coil C11, which are connected in series, has a second V-phase connecting wire CW_V2, a second lead wire L2, and an eleventh lead wire L11. The second V-phase connecting wire CW_V2 is placed on the other of the upper and lower sides of the stator core 11 and relays both coils C2 and C11. In this embodiment, the second V-phase connecting wire CW_V2 is placed on the upper side of the stator core 11. The second V-phase connecting wire CW_V2 is placed along, for example, the outer circumferential surface of the insulator 12 in the radial direction. The second V-phase connecting wire CW_V2 may be supported by part of the insulator 12. The second lead wire L2 is led from the second coil C2. The eleventh lead wire L11 is led from the eleventh coil C11.
A pair of the ninth coil C9 and twelfth coil C12, which are connected in series, has a first W-phase connecting wire CW_W1, a ninth lead wire L9, and a twelfth lead wire L12. The first W-phase connecting wire CW_W1 is placed on one of the upper and lower sides of the stator core 11 and relays both coils C9 and C12. In this embodiment, the first W-phase connecting wire CW_W1 is placed on the lower side of the stator core 11. The first W-phase connecting wire CW_W1 is placed along, for example, the outer circumferential surface of the insulator 12 in the radial direction. The first W-phase connecting wire CW_W1 may be supported by part of the insulator 12. The ninth lead wire L9 is led from the ninth coil C9. The twelfth lead wire L12 is led from the twelfth coil C12.
A pair of the third coil C3 and sixth coil C6, which are connected in series, has a second W-phase connecting wire CW_W2, a third lead wire L3, and a sixth lead wire L6. The second W-phase connecting wire CW_W2 is placed on the other of the upper and lower sides of the stator core 11 and relays both coils C3 and C6. In this embodiment, the second W-phase connecting wire CW_W2 is placed on the upper side of the stator core 11. The second W-phase connecting wire CW_W2 is placed along, for example, the outer circumferential surface of the insulator 12 in the radial direction. The second W-phase connecting wire CW_W2 may be supported by part of the insulator 12. The third lead wire L3 is led from the third coil C3. The sixth lead wire L6 is led from the sixth coil C6.
In this embodiment, on the lower side of the stator core 11, the first U-phase connecting wire CW_U1, first V-phase connecting wire CW_V1, and first W-phase connecting wire CW_W1 are placed in mutually distant areas in the circumferential direction. Moreover, on the upper side of the stator core 11, the second U-phase connecting wire CW_U2, second V-phase connecting wire CW_V2, and second W-phase connecting wire CW_W2 are placed in mutually distant areas in the circumferential direction. That is, on each of the upper and lower sides of the stator core 11, the connecting wire CW in one phase is placed in an area distant from the connecting wires CW in the other phases in the circumferential direction. The connecting wire CW in one phase does not overlap the connecting wires CW in the other phases in the circumferential direction.
In the stator 10, the connecting wires CW in three phases do not overlap one another in the circumferential direction on the upper and lower sides of the stator core 11, so the possibility that mutual contacts of connecting wires CW occur can be reduced. Therefore, the use of a part, such as an insulating tube, to assure insulation of the connecting wires CW can be eliminated. Moreover, the position in the up-and-down direction at which the connecting wire CW in each phase is disposed does not need to be shifted to avoid mutual contacts of the connecting wires CW, so the stator 10 and motor 1 can be downsized. According to the structure in this embodiment, since the placement of the connecting wires CW can be simplified, the use of an automated line is possible. According to the structure in this embodiment, since conducting wires can be easily wound on the stator core 11, the manufacturing cost can be reduced. Incidentally, the connecting wires CW may be placed at the outer edge of the stator 10 on the outer side in the radial direction or may be placed at the inner edge on the inner side in the radial direction. Moreover, the connecting wires CW may be placed on one of both end faces of the stator 10 in the axial direction.
Lead wires L led from the plurality of coils C in the up-and-down direction are all led in the same direction. In this embodiment, the first to twelfth lead wires L1 to L12 led in the up-and-down direction are all led in the same direction. To be more specific, the first to twelfth lead wires L1 to L12 are all led upward. In this structure, the whole of the bus bar 30, which connects lead wires L, can be placed on one of the upper and lower sides of the stator core 11. In this embodiment, the whole of the bus bar 30 is placed on the upper side of the stator core 11.
To be more specific, the bus bar 30 has a first bus bar 301, a second bus bar 302, and a third bus bar 303. The first bus bar 301 is connected to the first lead wire L1, eighth lead wire L8, tenth lead wire L10, and eleventh lead wire L11. The second bus bar 302 is connected to the second lead wire L2, third lead wire L3, fifth lead wire L5, and twelfth lead wire L12. The third bus bar 303 is connected to the fourth lead wire L4, sixth lead wire L6, seventh lead wire L7, and ninth lead wire L9. Thus, the first to twelfth coils C1 to C12 are delta-connected. The first bus bar 301, second bus bar 302, and third bus bar 303 are held in the bus bar unit 31 without being electrically connected mutually. In this embodiment, the first bus bar 301, second bus bar 302, and third bus bar 303 are held in the bus bar unit 31 in a state in which their positions in the radial direction are mutually shifted.
In this embodiment, in each coil pair CS, the connecting wire CW connects the outer sides, in the circumferential direction, of two coils C placed in the circumferential direction. This structure holds for all the six coil pairs CS. When this structure is taken, it is possible to form each coil C easily in a state in which tension is applied to the conducting wire and to reduce the possibility that, after the coil C has been formed, the lead wire slackens.
In the U-phase coil group UG, the first coil C1 and fourth coil C4 form a coil pair CS and the seventh coil C7 and tenth coil C10 form a coil pair CS. This point is the same as the structure in the first embodiment described above. In these two coil pairs CS, however, the first coil C1 and seventh coil C7 are electrically connected and the fourth coil C4 and tenth coil C10 are electrically connected, forming a parallel connection. That is, the way of forming a parallel connection differs from the structure in the first embodiment described above.
In the V-phase coil group VG, the second coil C2, and eleventh coil C11 form a coil pair CS and the fifth coil C5 and eighth coil C8 form a coil pair CS. This point is the same as the structure in the first embodiment described above. In these two coil pairs CS, however, the second coil C2 and eighth coil C8 are electrically connected and the fifth coil C5 and eleventh coil C11 are electrically connected, forming a parallel connection. That is, the way of forming a parallel connection differs from the structure in the first embodiment described above.
In the W-phase coil group WG, the third coil C3 and sixth coil C6 form a coil pair CS and the ninth coil C9 and twelfth coil C12 form a coil pair CS. This point is the same as the structure in the first embodiment described above. In these two coil pairs CS, however, the third coil C3 and ninth coil C9 are electrically connected and the sixth coil C6 and twelfth coil C12 are electrically connected, forming a parallel connection. That is, the way of forming a parallel connection differs from the structure in the first embodiment described above.
As illustrated in
In a coil pair of the second coil C2 and eleventh coil C11, a coil pair of the third coil C3 and sixth coil C6, and a coil pair of the seventh coil C7 and tenth coil C10, the connecting wire CW connects the inner sides, in the circumferential direction, of the two coils C placed in the circumferential direction in the circumferential direction. That is, in the variation, some coil pairs CS do not have a structure in which the connecting wire CW connects the outer sides, in the circumferential direction, of two coils C placed in the circumferential direction. This point differs from the structure in the first embodiment described above.
In the structure in the variation as well, on the upper and lower sides of the stator core 11, the connecting wire CW in one phase is placed in an area distant from the connecting wires CW in the other phases in the circumferential direction. That is, the connecting wires CW in three phases do not overlap one another in the circumferential direction on the upper and lower sides of the stator core 11, so the possibility that mutual contacts of connecting wires CW occur can be reduced. Therefore, the use of a part, such as an insulating tube, to assure insulation of the connecting wires CW can be eliminated. Moreover, the position in the up-and-down direction at which the connecting wire CW in each phase is disposed does not need to be shifted to avoid mutual contacts of the connecting wires CW, so the stator 10 and motor 1 can be downsized. Also, since the lead wires L are all led upward, the whole of the bus bar 30 can be placed on the upper side of the stator core 11.
In descriptions of the connection structure of coils in the second embodiment, descriptions overlapping the first embodiment will be omitted when the descriptions are not required.
In the second embodiment, of the lead wires L led from the plurality of coils C in the up-and-down direction, a lead wire connected to a neutral point and other lead wires are led in opposite directions. To be more specific, of the first to twelfth lead wires L1 to L12 led in the up-and-down direction, the first, second, fifth, sixth, ninth, and tenth lead wires and the third, fourth, seventh, eighth, eleventh, and twelfth lead wires are led in opposite directions. In this embodiment, the first, second, fifth, sixth, ninth, and tenth lead wires are led upward. The third, fourth, seventh, eighth, eleventh, and twelfth lead wires are led downward.
In the second embodiment, the bus bar 30 has a first bus bar 304, a second bus bar 305, a third bus bar 306, and a fourth bus bar 307. The first bus bar 304 is connected to the first lead wire L1 and tenth lead wire L10. The second bus bar 305 is connected to the second lead wire L2 and fifth lead wire L5. The third bus bar 306 is connected to the sixth lead wire L6 and ninth lead wire L9. The fourth bus bar 307 is connected to the third, fourth, seventh, eighth, eleventh, and twelfth lead wires L3, L4, L7, L8, L11, and L12. The fourth bus bar 307 is a bus bar intended for a neutral point. Thus, the first to twelfth coils C1 to C12 are star-connected. The first, second, and third bus bars 304 to 306 are held in the bus bar unit 31, which is placed on the upper side of the stator core 11, without being electrically connected mutually. In this embodiment, three bus bars, 304 to 306, are held in the bus bar unit 31 in a state in which their positions in the radial direction are mutually shifted. The fourth bus bar 307 is placed on the lower side of the stator core 11. The fourth bus bar 307 may also be supported by a resin.
In the structure in the second embodiment as well, on the upper and lower sides of the stator core 11, the connecting wire CW in one phase is placed in an area distant from the connecting wires CW in the other phases in the circumferential direction. That is, the connecting wires CW in three phases do not overlap one another in the circumferential direction on the upper and lower sides of the stator core 11, so the possibility that mutual contacts of connecting wires CW occur can be reduced. Moreover, in all coil pairs CS, the connecting wire CW connects the outer sides, in the circumferential direction, of two coils C placed in the circumferential direction. Therefore, it is possible to form each coil C easily in a state in which tension is applied to the conducting wire and to reduce the possibility that, after the coil C has been formed, the lead wire slackens.
In the variation illustrated in
Incidentally, in the structure in the variation, since the fourth bus bar 307 is also placed on the upper side of the stator core 11, the fourth bus bar 307 is also held in the bus bar unit 31. The first, second, third, and fourth bas bars 304 to 307 are held in the bus bar unit 31, without being electrically connected mutually.
In the structure in the variation as well, the connecting wires CW in three phases do not overlap one another in the circumferential direction on the upper and lower sides of the stator core 11, so the possibility that mutual contacts of connecting wires CW occur can be reduced. Moreover, in all coil pairs CS, the connecting wire CW connects the outer sides, in the circumferential direction, of two coils C placed in the circumferential direction. Therefore, it is possible to form each coil C easily in a state in which tension is applied to the conducting wire and to reduce the possibility that, after the coil C has been formed, the lead wire slackens.
The structures in the embodiments indicated above are merely exemplary of the present disclosure. The structures in the embodiments may be appropriately changed within a range not exceeding the technical concept of the present disclosure. It is also possible to practice a plurality of embodiments, variations in each embodiment, and the like by combining them to the extent possible.
So far, a case has been indicated in which the motor and stator core in the present disclosure are applied to an electric brake booster. However, this is merely exemplary. The present disclosure can be widely applied to, for example, an electric power steering apparatus, a pump, an antilock braking system, and other applications.
The present disclosure can be widely applied to motors used in, for example, home electrical appliances, automobiles, ships, aircraft, trains, and the like.
Features of the above-described preferred embodiments and the modifications thereof may be combined appropriately as long as no conflict arises.
While preferred embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2016/072267 | 7/29/2016 | WO | 00 |
