JP2013223297A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine in which, even if coils of a plurality of systems are provided, the number of rows of bus bars for connecting coils of each of the systems can be reduced.SOLUTION: A rotary electric machine includes twelve split cores 31 that are cylindrically arranged and divided into two groups of six continuous cores, and bus bars 25 that are provided for each of the groups. The bus bars of each of both groups are provided in a range within a half of the circumference of a stator, so that the bus bars 25 of both groups do not overlap with each other. Further, bus bars of the same phase in each of the groups have the same shape. In addition, a connection position with the bus bars 25 to be connected can be adjusted by crossing both ends of a plurality of coils 18 connected to each of the bus bar groups with each other, whereby each of the coils 18 and each of the bus bars 25 can be suitably connected while a state where the number of rows of the bus bar 25 is reduced is maintained.

Description

  The present invention relates to a rotating electrical machine such as a motor.

  Conventionally, as shown in Patent Document 1, a motor that supplies three-phase AC power to each coil via a plurality of bus bars is known. Each phase (U-phase, V-phase, W-phase) bus bar is formed by spirally bending a band-shaped metal member. The bus bars of each phase are arranged in the radial direction of the motor and are provided at different positions in the circumferential direction of the motor. Each bus bar forms a maximum of three rows in the radial direction of the motor by overlapping each other in the circumferential direction of the motor. If the bus bars for neutral points are included, each bus bar has a maximum of 4 rows in the radial direction of the motor.

  The motor is used as a drive source for an electric power steering apparatus, for example. The apparatus applies a steering assist force to the steering system of the vehicle using the rotational force of the motor. When the motor fails, it becomes difficult to generate a steering assist force. For this reason, a motor as shown in Patent Document 2 has been conventionally proposed. This motor has two coils, and power is supplied to each of these coils. According to this configuration, the motor can be rotated through power feeding to the coil of the other system even when the coil of one system has failed. Although the steering assist force applied to the steering system is about half that of the normal time, the steering assist operation can be continued.

JP 2010-239772 A JP 2004-010024 A

  However, when two coils are provided in the motor, there are the following problems. That is, since it is necessary to provide two bus bars, the number of bus bars increases. Further, since the bus bars need to be provided so as not to interfere with each other, the number of bus bar rows in the radial direction of the motor also increases. When the number of rows of bus bars increases, there is a concern about increasing the outer diameter of the motor, and consequently the size of the motor.

  The present invention has been made in order to solve the above-described problems, and the purpose thereof is to provide a rotating system capable of reducing the number of rows of bus bars connecting the coils of each system, even when a plurality of systems of coils are provided. It is to provide an electric machine.

  According to one aspect of the present invention, a cylindrical stator having a plurality of coils arranged in an annular shape and a rotor that rotates concentrically relative to the stator, and each coil is arranged in a row. Are divided into a plurality of groups, and each group has a bus bar group that distributes the three-phase AC power supplied by a separate system to the coils of each group in the circumferential direction of the stator. In addition, the bus bar groups of the respective coils are formed by crossing both ends of the plurality of coils among the coils connected to each bus bar group, with the same shape of the bus bars of the same phase in each group being provided. There is provided a rotating electrical machine having a connection position adjusted with respect to the rotating electric machine.

  According to this configuration, coils belonging to a plurality of groups, each including a plurality of coils arranged continuously in the circumferential direction of the stator, are unevenly distributed in different portions on the same circumference. For this reason, since the bus bar groups of each group can be provided separately from each other in the circumferential direction of the stator, the bus bars of the groups adjacent to each other do not overlap each other. Therefore, even though the coils for a plurality of systems are provided, it is possible to provide, for example, bus bars of two different phases on the same circumference through adjustment of the length and arrangement of each bus bar. That is, the number of rows of bus bars can be reduced as compared with the case where the bus bars for each phase are all provided on different circumferences. It is also possible for the in-phase bus bars in each group to have the same shape.

  However, even if the number of rows of bus bars is reduced, or even if the shapes of the in-phase bus bars in each group can be made the same, it is conceivable that the connection positions of the coils to the bus bars do not match. In this regard, by connecting the ends of a plurality of coils among the coils connected to each bus bar group, the connection position of each coil with respect to each bus bar can be adjusted. Thereby, each coil and each bus bar can be suitably connected while maintaining a state in which the number of rows of bus bars is reduced.

<2> In the above rotating electrical machine, the coils of each group are preferably star-delta connected via a bus bar group provided for each group.
When the star delta connection is employed, a neutral point bus bar is required in addition to the three-phase bus bar. For this reason, it is significant to reduce the number of bus bars.

  According to the present invention, even when a plurality of coils are provided, the number of rows of bus bars connecting the coils of each system can be reduced.

The longitudinal cross-sectional view of the motor in one embodiment. FIG. 1 is a sectional view taken along line 1-1 of FIG. The connection diagram which shows the connection relationship between a bus bar and a coil. (A) is a circuit diagram of a coil connected in Y-Δ, and (b) is a connection diagram of the coil. The connection diagram which similarly shows the other connection relation of a bus-bar and a coil.

<First Embodiment>
Hereinafter, an embodiment in which the present invention is embodied in an inner rotor type brushless motor will be described with reference to FIGS.

<Overall configuration>
As shown in FIG. 1, the motor 11 includes a bottomed cylindrical case 12 and a lid 13 that closes the opening of the case 12. A cylindrical stator 14 is fixed to the inner peripheral surface of the case 12. The stator 14 includes a cylindrical core 15, two insulators 16 and 17 provided at both ends of the core 15, and a plurality of coils 18 wound around the core 15 via the insulators 16 and 17. ing.

  A cylindrical rotor 19 is inserted into the stator 14. The rotor 19 includes a stepped columnar rotating shaft 20 and a cylindrical rotor magnet 21 fixed to the outer peripheral surface of the rotating shaft 20. The rotating shaft 20 is rotatably supported via two bearings 22 and 23 provided on the inner bottom of the case 12 and the inner surface of the lid 13.

  A disc-shaped holder 24, which is a resin molded product, is provided at the end of the stator 14 on the lid 13 side. The holder 24 holds a plurality of bus bars 25. Both ends of each coil 18 are appropriately connected to each bus bar 25. Three-phase AC power is supplied to each coil 18 via each bus bar 25.

<Rotor magnet and core>
As shown in FIG. 2, the rotor magnet 21 is formed by arranging 14 permanent magnets 21 a along the outer peripheral surface of the rotating shaft 20 without a gap. Each permanent magnet 21a is magnetized along the radial direction of the rotating shaft 20, and is provided so that the magnetization directions of two permanent magnets 21a adjacent to each other are opposite to each other.

  The core 15 is formed by arranging 12 divided cores 31 along the inner peripheral surface of the case 12 without a gap. Here, as indicated by the circled numbers in FIG. 2, the divided cores 31 are distinguished by assigning numbers 1 to 12. The twelve divided cores 31 are divided into two groups of systems A and B with a straight line PL extending in the radial direction of the core 15 as a boundary. The group A of the system A includes six divided cores 31 (No. 1 to No. 6) corresponding to the half of the 12 divided cores 31 provided on the same circumference, and the group of the system B is the remaining six of the half circumference. The number of divided cores 31 (Nos. 7 to 12) is included. A coil 18 is wound around each divided core 31.

<Bus bar>
As shown in FIG. 3, the motor 11 has eight bus bars 25. Each bus bar 25 is formed by appropriately bending a metal plate punched into a predetermined shape. Each bus bar 25 has three connection terminals T. The connection terminal T is a portion to which the end portion (lead portion) of the coil 18 is connected.

  Each bus bar 25 is also divided into two groups of systems A and B with the straight line PL as a boundary. Each group includes four bus bars 25, specifically, a U-phase bus bar 25u, a V-phase bus bar 25v, a W-phase bus bar 25w, and a neutral point bus bar 25n. Each bus bar 25 of the system A is in a range within half a circumference of the core 15 corresponding to the first to sixth divided cores 31, and each bus bar 25 of the system B is a core corresponding to the seventh to twelfth divided cores 31. It is provided in a range within 15 remaining half-circles. For this reason, each bus bar 25 of the system A and each bus bar 25 of the system B do not overlap each other in the circumferential direction of the core 15.

  Each bus bar 25 of the system A is provided as follows. That is, the U-phase bus bar 25u is assigned to the first to sixth divided cores 31, the V-phase bus bar 25v is assigned to the fourth to sixth divided cores 31, and the W-phase bus bar 25w is assigned to the second to fourth divided cores 31. Each is extended to correspond. The neutral point bus bar 25n is extended to correspond to the first to fifth divided cores 31.

  Each bus bar 25 of the system B is provided as follows. That is, the U-phase bus bar 25u is the 7th to 12th divided core 31, the V phase bus bar 25v is the 10th to 12th divided core 31, and the W phase bus bar 25w is the 8th to 10th divided core 31. Each is extended to correspond. The neutral point bus bar 25n extends so as to correspond to the seventh to eleventh divided cores 31.

  In each of the systems A and B, each bus bar 25 is provided on three concentric circles centered on the central axis of the core 15. Specifically, when the first column, the second column, and the third column are sequentially arranged from the concentric circles close to the central axis of the core 15, the neutral point bus bar 25n is provided in the first column. The V-phase bus bar 25v and the W-phase bus bar 25w are provided in the second row, and the U-phase bus bar 25u is provided in the third row.

  Note that the V-phase bus bar 25v and the W-phase bus bar 25w of the system A have the same shape. The V-phase bus bar 25v and the W-phase bus bar 25w of the system B have the same shape. In systems A and B, the bus bars in phase with each other have the same shape. Specifically, the U phase bus bar 25u of system A and the U phase bus bar 25u of system B, the V phase bus bar 25v of system A, the V phase bus bar 25v of system B, the W phase bus bar 25w of system A and the W phase of system B The bus bar 25w has the same shape as each other.

  Further, the bus bars 25 of the three-phase each phase in the groups of both systems are connected to an ECU (electronic control unit) (not shown). This ECU includes two drive circuits corresponding to the systems A and B, and performs energization control for each bus bar 25 and eventually each coil 18 for each system through these drive circuits.

  That is, corresponding to the two groups of the systems A and B of the split core 31, each bus bar 25 and the drive circuit are also separate systems. For this reason, even if one system fails, for example, when the coil 18 of one system is disconnected or short-circuited or the drive circuit fails, the rotor 19 can be rotated by the operation of the other system. it can. Although the torque generated by the motor 11 is reduced, the driving of the motor 11 can be continued.

<Coil connection method>
Next, a method for connecting the coils will be described. Each coil 18 is distinguished by the number (No. 1 to No. 12) of the divided core 31 provided with these coils. As shown in FIGS. 4A and 4B, the first to sixth coils 18 of the system A are star-delta connected (Y-Δ connection) via the bus bars 25 of the system A. Similarly, the No. 7 to No. 12 coils 18 of the system B are also Y-Δ connected via the bus bars 25 of the system B.

  Specifically, as shown in FIG. 4A, the odd-numbered coils 18 among the coils 18 of the systems A and B are star-connected (Y-connected). Further, the even-numbered coils 18 are delta-connected (Δ-connected). Further, the odd-numbered coil group Y-connected and the even-numbered coil group Δ-connected are connected in parallel.

  As shown in FIG. 4B, the first and seventh coils 18 are U phase coils (U−, U +), and the fifth and eleventh coils 18 are V phase coils (V−, V +) and third. The ninth coil 18 functions as a W-phase coil (W +, W-). The 6th and 12th coils 18 are X-phase coils (X-, X +), the 4th and 10th coils 18 are Y-phase windings (Y +, Y-), and the 2nd and 8th coils 18 are Z Each functions as a phase coil (Z−, Z +). In FIG. 4B, the signs “+” and “−” of the phase symbols (U, V, W) given to the coils 18 indicate that the phases of the currents supplied to the coils 18 are 180 ° ( It shows that it is shifted by electrical angle.

<Coil connection of system A>
As shown in FIG. 3, both ends (lead portions) of the first, third, and fourth coils 18 of the A system are drawn straight toward the axial direction (upward in the drawing) of the core 15. The other ends of the remaining second, fifth and sixth coils 18 intersect each other.

  First, the connection state of the coil 18 whose ends are not intersected will be described. The first end of the first coil 18 is connected to the U-phase bus bar 25u, and the second end is connected to the neutral point bus bar 25n. The first end of the third coil 18 is connected to the neutral point bus bar 25n, and the second end is connected to the W-phase bus bar 25w. The first end of the fourth coil 18 is connected to the W-phase bus bar 25w, and the second end is connected to the V-phase bus bar 25v.

  Next, the connection state of the coil 18 whose both ends are crossed will be described. Since both ends of the second coil 18 intersect each other, the first end located near the first coil 18 in the circumferential direction of the core 15 is moved away from the first coil 18, and the first coil 18 is also the same. The second end located far from the second coil reaches a position close to the first coil 18. That is, the positions of the first end and the second end of the second coil 18 are switched. As a result, in the axial direction of the core 15, the first end of the second coil 18 is located corresponding to the connection terminal T of the W-phase bus bar 25w, and the second end is located corresponding to the connection terminal T of the U-phase bus bar 25u. Assuming this state, the first end of the second coil 18 is connected to the W-phase bus bar 25w, and the second end is connected to the U-phase bus bar 25u.

  The same applies to the fifth and sixth coils 18. That is, in the axial direction of the core 15, the first end of the fifth coil 18 is located corresponding to the connection terminal T of the V-phase bus bar 25v, and the second end is located corresponding to the connection terminal T of the neutral point bus bar 25n. The first end of the fifth coil 18 is connected to the V-phase bus bar 25v, and the second end is connected to the neutral point bus bar 25n. Further, in the axial direction of the core 15, the first end of the sixth coil 18 is located corresponding to the connection terminal T of the U-phase bus bar 25u, and the second end is located corresponding to the connection terminal T of the V-phase bus bar 25v. The first end of the sixth coil 18 is connected to the U-phase bus bar 25u, and the second end is connected to the V-phase bus bar 25v.

<Coil connection of system B>
As shown in FIG. 3, both ends (lead portions) of the eighth, eleventh, and twelfth coils 18 of the B system are drawn straight toward the axial direction of the core 15 (upward in the drawing). The other ends of the remaining No. 7, No. 9, No. 9 and No. 10 coils 18 intersect each other.

  First, the connection state of the coil 18 whose ends are not intersected will be described. The first end of the eighth coil 18 is connected to the U-phase bus bar 25u, and the second end is connected to the W-phase bus bar 25w. The 11th coil 18 has a first end connected to the neutral point bus bar 25n and a second end connected to the V-phase bus bar 25v. The 12th coil 18 has a first end connected to the V-phase bus bar 25v and a second end connected to the U-phase bus bar 25u.

  Next, the connection state of the coil 18 whose both ends are crossed will be described. In the axial direction of the core 15, the first end of the seventh coil 18 is located corresponding to the connection terminal T of the neutral point bus bar 25n, and the second end is also located corresponding to the connection terminal T of the U-phase bus bar 25u. The first end of the seventh coil 18 is connected to the neutral point bus bar 25n, and the second end is connected to the U-phase bus bar 25u.

  In the axial direction of the core 15, the first end of the ninth coil 18 is located corresponding to the connection terminal T of the W-phase bus bar 25w, and the second end is located corresponding to the connection terminal T of the neutral point bus bar 25n. The first end of the ninth coil 18 is connected to the W-phase bus bar 25w, and the second end is connected to the neutral point bus bar 25n.

  Further, in the axial direction of the core 15, the first end of the tenth coil 18 is located corresponding to the connection terminal T of the V-phase bus bar 25v, and the second end is located corresponding to the connection terminal T of the W-phase bus bar 25w. The 10th coil 18 has a first end connected to the V-phase bus bar 25v and a second end connected to the W-phase bus bar 25w.

<Operation by connection of lines A and B>
The bus bars 25 of the system A and the bus bars 25 of the system B do not overlap with each other in the circumferential direction of the core 15. For this reason, as shown in FIG. 3 above, by adjusting the length of each bus bar 25, for example, the V-phase bus bar 25v and the W-phase bus bar 25w can be provided on the same circumference, that is, in the same row. . However, even if the number of rows of each bus bar 25 can be three, the positions in the circumferential direction of the core 15 between the connection terminal T of each bus bar 25 and both ends of each coil 18 do not necessarily match. In the example of FIG. 3, assuming that both ends of each coil 18 are pulled out along the axial direction of the core 15, the second, fifth, and sixth coils 18 of the A system, and the seventh, ninth, and 10 of the B system. The number coil 18 does not correspond to the connection terminal T of the bus bar 25 to be connected.

  Here, in the circumferential direction of the core 15, for example, the amount of displacement between the first end of the second coil 18 and the connection terminal T of the W-phase bus bar 25 w to be connected, and the second end of the second coil 18. And the amount of displacement from the connection terminal T of the U-phase bus bar 25u that is the connection target is exactly the same in the circumferential direction of the core 15 when both ends of the second coil 18 are extended along the axial direction of the core 15. Equal to the distance between the first end and the second end.

  Therefore, as described above, the positions of the first end and the second end of the second coil 18 are interchanged in the circumferential direction of the core 15, that is, by crossing both ends of the second coil 18, One end corresponds to the connection terminal T of the W-phase bus bar 25w to be connected, and the second end similarly corresponds to the connection terminal T of the U-phase bus bar 25u to be connected. The same applies to the remaining fifth and sixth coils 18 and the seventh, ninth and tenth coils 18.

  As described above, in the example of FIG. 3, by crossing both ends of the second, fifth, and sixth coils 18 of the A system and the seventh, ninth, and tenth coils 18 of the B system, the connection target is obtained. The connection position with the bus bar 25 is adjusted.

Incidentally, the number of rows of the bus bars 25 cannot always be three by simply providing the bus bars 25 separately for each group of the systems A and B.
For example, as shown in FIG. 5, it is conceivable that both ends of each coil 18 are drawn straight toward the axial direction of the core 15, and the drawn ends are connected to the bus bar 25 to be connected. However, in this case, the bus bar 25 needs to be present at positions corresponding to both ends of each coil 18. For this reason, it is necessary to ensure the length of the bus bar 25 of each phase to a certain extent. As a result, it is difficult to provide bus bars 25 of different phases on the same circumference within a range within a half circumference of the core 15. In order to provide the bus bars 25 of the respective phases without interfering with each other, the bus bars 25 of the respective phases must be provided at different positions in the radial direction of the core 15 so that the number of rows of the bus bars 25 must be four.

  In addition to appropriately setting the length and arrangement of each bus bar 25 as in this example, the number of rows of each bus bar 25 can be reduced by appropriately mixing a coil 18 that intersects both ends and a coil 18 that does not intersect both ends. Can be arranged in three rows.

<Effect of Embodiment>
Therefore, according to the present embodiment, the following effects can be obtained.
(1) Twelve divided cores 31 arranged in a cylindrical shape were divided into two groups (systems A and B), each group consisting of six consecutive cores. The bus bar 25 is also provided for each system, and each bus bar of both systems is provided within a range of half a circumference of the stator 14. For this reason, the bus bars 25 of the systems A and B do not overlap each other. Therefore, in spite of the provision of the coils 18 for two systems, the number of rows of the bus bars 25 is adjusted to 3 rows, which is smaller than the 4 rows of the conventional one system motor, by adjusting the length and arrangement of each bus bar 25. Can be. For example, by providing the V-phase and W-phase bus bars 25v and 25w on the same circumference and within a half circumference of the core 15, the number of rows of each bus bar 25 is three.

  Furthermore, in this example, in each group of the systems A and B, the connection position with each bus bar 25 is adjusted by appropriately mixing the coil 18 that intersects both ends and the coil 18 that does not intersect. Therefore, even when the length of each bus bar 25 is shortened, the connection position with respect to each bus bar 25 can be adjusted with a certain degree of freedom according to the length of each bus bar 25 or the position with respect to the core 15. It is. Therefore, each coil 18 and each bus bar 25 can be suitably connected in a state where the number of rows of bus bars 25 is maintained at three.

  (2) Further, the greater the number of coils 18 to be crossed, the greater the degree of freedom in adjusting the connection position for each bus bar 25. For this reason, among the bus bars 25 of the systems A and B, the shapes of the bus bars 25 having the same phase can be made the same. In addition, the V-phase bus bar 25v and the W-phase bus bar 25w of the same system can have the same shape. Therefore, the types of parts can be reduced.

  (3) The outer diameter or physique of the motor 11 can be reduced by the amount corresponding to the reduction in the number of rows of the bus bars 25. For this reason, the motor 11 of this example is suitable as a drive source of a device having a limited mounting space such as an electric power steering device. Further, the motor 11 of this example may be adopted as a drive source for an electric pump or a variable gear ratio steering (VGRS) of an automobile. VGRS is a device that changes the steering gear ratio steplessly in accordance with the vehicle speed and the steering angle.

  (4) The cylindrical stator 14 was divided into two semi-cylindrical parts corresponding to the systems A and B. A bus bar 25 was also provided for each system. That is, the power supply system for the motor 11 was divided into two systems, systems A and B. For this reason, even if one system fails, the operation of the motor 11 can be continued by the other system. For this reason, the reliability of the motor 11 can be ensured.

<Other embodiments>
Each of the above embodiments may be modified as follows.
In this example, in each of the systems A and B, the Y-Δ connection is adopted as the connection method of each coil 18, but a Δ connection or a Y connection may be used. In this case, the length and shape of each bus bar 25 or the end treatment shape of each coil 18 (whether or not to intersect) is adjusted as appropriate. Incidentally, in the case of Δ connection, the neutral point bus bar 25 is not necessary. Therefore, the number of bus bars 25 can be two.

In this example, the rotor magnet 21 composed of a plurality of permanent magnets 21a is employed, but a single cylindrical magnet may be employed.
-In this example, although the core 15 which consists of the some division | segmentation core 31 was employ | adopted, you may employ | adopt a single core. Even in this case, the coils 18 can be divided into two groups of systems A and B.

  In this example, a so-called 14-pole 12-coil brushless motor has been described as an example, but the number of coils 18 and the number of magnetic poles of the rotor magnet 21 may be changed as appropriate. In this case, it is preferable to set the number of coils 18 to a natural number multiple of 12, and the number of magnetic poles of the rotor magnet 21 to a natural number multiple of 2, 10 or 14.

  In this example, the power supply system for the motor 11 is two systems A and B, but may be three systems, four systems or more. Also in this case, it is preferable that each system is set to have an equiangular range in the circumferential direction of the stator 14.

  In this example, the inner rotor type brushless motor is taken as an example, but an outer rotor type brushless motor may be used. In the same type of motor, a stator is provided inside a cylindrical rotor.

In the present example, the present invention is embodied as a brushless motor, but the present invention may be applied to a generator (rotating electric machine).
<Other technical ideas>
Next, a technical idea that can be grasped from the above embodiment will be added below.

(A) In the rotating electrical machine according to claim 1 or 2, the stator includes a plurality of divided cores having coils arranged in an annular shape.
(B) In an electric device such as an electric power steering device, the electric rotating machine according to claim 1, 2 or (a) is provided as a drive source.

  DESCRIPTION OF SYMBOLS 11 ... Motor (rotary electric machine), 14 ... Stator, 18 ... Coil, 19 ... Rotor, 25 ... Bus bar.

Claims (2)

A cylindrical stator having a plurality of coils arranged in a ring, and a rotor that rotates concentrically relative to the stator, and
Each coil is divided into a plurality of groups in which a plurality of coils arranged continuously are grouped, and a bus bar group that distributes the three-phase AC power supplied by a separate system to the coils of each group for each group. And along the circumferential direction of the stator,
Furthermore, after making the shape of the in-phase bus bar in each group the same, the connection position of each coil to each bus bar group is made by crossing both ends of each of the coils connected to each bus bar group. A rotating electric machine that is adjusted. In the rotating electrical machine according to claim 1,
The coils of each group are rotating electrical machines that are star-delta connected via a bus bar group provided for each group.