WO2023140074A1

WO2023140074A1 - Motor stator and motor equipped with same

Info

Publication number: WO2023140074A1
Application number: PCT/JP2022/048254
Authority: WO
Inventors: 隼人小林; 直嗣北山
Original assignee: Ntn株式会社
Priority date: 2022-01-20
Filing date: 2022-12-27
Publication date: 2023-07-27
Also published as: JP2023106033A

Abstract

Provided is a motor stator 1 comprising a coil C wound onto radial teeth 4 provided on a cylindrical stator core 2 with an insulating member 10 therebetween, and a busbar 5 having a wire connection terminal 5a, wherein: the insulating member 10 has a holding part 13 which holds the busbar 5 on one axial end side of the stator core 2; a coil wire CL drawn out from the coil C to the one axial end side of the stator core 2 is connected to the wire connection terminal 5a of the busbar 5 while being tied to the wire connection terminal 5a; and the holding part 13 is provided with a mitigating part 14 which mitigates a tensile force that acts on the wire connection terminal 5a due to the coil wire CL being tied to the wire connection terminal 5a.

Description

Motor stator and motor provided with the same

The present invention relates to a motor stator and a motor including the same, and more particularly to a brushless motor stator that can be suitably used as a drive source for electrical equipment mounted on a vehicle (automobile) such as an electric oil pump and an electric parking brake.

Patent Document 1 below discloses an inner rotor type three-phase brushless motor that includes a motor stator in which a coil (a U-phase coil, a V-phase coil, or a W-phase coil) is wound on each of a plurality of teeth spaced apart in the circumferential direction on a cylindrical stator core via an insulating member also called an insulator, and a motor rotor arranged radially inward of the motor stator. In the above motor stator, a coil wire (also referred to as a “lead wire”) drawn out from the coil wound around the teeth to the axially outer side of the stator core is connected (electrically connected) to the bus bar to form a motor drive circuit (power supply circuit). The motor stator of Patent Document 1 includes a busbar unit arranged coaxially with the stator core, and the busbar unit holds a U-phase busbar, a V-phase busbar, a W-phase busbar, and a neutral point busbar, each having a coil wire connection terminal, in a non-contact state.

International publication WO2020/013078

In the motor disclosed in Patent Literature 1, the busbars having coil wire connection terminals are held by a busbar unit provided separately from the stator core.
(1) After the coil is wound, it is necessary to align the coil wire drawn from the coil with the connection terminal of the bus bar.
(2) After the coil is wound, there is a risk that the shape accuracy of the coil may deteriorate due to looseness in the winding of the coil, etc. during the period from the time the coil is wound until the coil wire pulled out from the coil is connected.
And so on.

Therefore, the main object of the present invention is to provide a motor stator that is excellent in coil shape accuracy and capable of stably exerting a predetermined output at low cost.

The present invention, which has been devised to achieve the above objects,
A motor stator comprising a cylindrical stator core, coils wound around radial teeth provided on the stator core via an insulating member, and bus bars having connection terminals and external connection terminals,
The insulating member has a holding portion that holds the busbar on one axial end side of the stator core,
a coil wire drawn out from the coil to one axial end side of the stator core is connected to the connection terminal in a state of being entwined with the connection terminal of the busbar held by the holding portion;
The holding portion is provided with a relief portion that relieves a tensile force acting on the connection terminal due to the coil wire being entwined around the connection terminal.

In the motor stator according to the present invention, the insulating member has a holding portion that holds the busbar on one axial end side of the stator core. This means that the insulating member for insulating between the teeth and the coil wound thereon integrally has a portion that holds the bus bar of the conventional product disclosed in Patent Document 1. Therefore, the number of parts can be reduced compared to the conventional product.

Also, in the present invention, the coil wire pulled out from the coil is connected to the connection terminal in a state of being entwined with the connection terminal of the busbar held by the holding portion. Such a configuration can be obtained, for example, by entwining the intended connection portion of the coil wire with respect to the connection terminal when winding the coil, and then connecting the intended connection portion (entangled portion) of the coil wire to the connection terminal. In short, in the motor stator according to the present invention, the coil wire connection operation can be performed in a state in which the coil wire connection planned locations are positioned with respect to the connection terminals. Therefore, the coil wire connection operation can be smoothly (efficiently) performed with respect to the connection terminals while preventing deterioration in the shape accuracy of the coil as much as possible. However, when the coil wire is entwined with the connection terminals of the busbar, the associated tensile force is continuously applied to the connection terminals, so there is a possibility that the connection terminals will be deformed or damaged, making it impossible to maintain a proper connection state. In this respect, according to the present invention, since the holding portion of the insulating member is provided with the relief portion for relieving the tensile force, it is possible to prevent such a problem from occurring as much as possible.

The relief part can have, for example, a first projection and a second projection provided separately from each other. In this case, if the portions of the coil wire located upstream and downstream of the portion connected to the connection terminal are respectively wrapped around the first projection and the second projection, the tensile force acting on the connection terminal can be effectively alleviated.

At least a part of the first projection and the second projection that constitute the relief portion can be provided so as to be arranged within a projection plane in which the connection terminal is projected in the axial direction. In this way, it is possible to enhance the ability to relax the tensile force.

The coil wire can be connected to the connection terminal by fusing, which is also called heat crimping, for example. In the case of fusing, the conductor wire can be joined to the connection terminal at substantially the same time as the insulation film of the coil wire made of the conductor wire with the insulation film is removed, so that the wire connection work can be performed efficiently and accurately.

The present invention can be preferably applied to a motor stator in which a plurality of teeth and coils wound thereon are provided at intervals in the circumferential direction, and a plurality of coils are formed by successively intensive winding of a single continuous coil wire around each of the plurality of teeth.

The present invention can be preferably applied, for example, to a motor stator for a 10-pole, 12-slot three-phase brushless motor. The 10-pole, 12-slot three-phase brushless motor includes, for example, an SPM type (a surface magnet type in which permanent magnets are attached to the outer periphery of the rotor) and an IPM type (an embedded magnet type in which permanent magnets are embedded in the rotor), in which the motor rotor has 10 permanent magnets and the motor stator has 12 slots, and a motor having a ring-shaped magnet with 10 circumferential poles and 12 slots.

Since the motor stator according to the present invention has the above features, the motor (three-phase brushless motor) comprising the motor stator and the motor rotor according to the present invention has the feature that it can stably produce a predetermined output and is highly reliable.

As described above, according to the present invention, it is possible to provide, at low cost, a motor stator that has excellent coil shape accuracy and is capable of stably exhibiting a predetermined output.

1 is a schematic perspective view of a motor stator according to an embodiment of the present invention before coil winding; FIG. FIG. 2 is a view of a bus bar separated from the motor stator of FIG. 1; 1 is a schematic plan view of a motor stator according to an embodiment of the invention; FIG. FIG. 2 is an enlarged view of a main part of the motor stator shown in FIG. 1; FIG. 2 is an enlarged view of a main portion of a motor stator wound with a coil; FIG. 5B is a cross-sectional view taken along the line AA in FIG. 5A; 4 is a diagram for explaining a winding structure of a coil in the motor stator of FIG. 3; FIG. FIG. 7 is a diagram showing a star-connected motor drive circuit obtained by the winding structure of FIG. 6 ; 1 is a longitudinal sectional view conceptually showing one configuration example of a motor provided with a motor stator according to an embodiment of the present invention; FIG.

Embodiments of the present invention will be described below with reference to the drawings (FIGS. 1 to 8). In the following description, the terms "axial direction," "radial direction," and "circumferential direction" are used to indicate directionality, and these are respectively the direction parallel to the axis of the motor stator 1, the radial direction of a circle centered on the axis, and the circumferential direction of a circle centered on the axis.

First, based on FIG. 8, a configuration example of the motor 30 including the motor stator 1 according to the embodiment of the present invention will be briefly described. A motor 30 shown in FIG. 8 includes a motor stator 1, a motor rotor 32 arranged radially inside the motor stator 1 with a radial gap (not shown) therebetween, and a casing 31 housing them. The illustrated motor rotor 32 includes an output shaft 33, a rotor core 34 provided to be rotatable integrally with the output shaft 33, and a plurality of (e.g., 10 poles) permanent magnets 35 held by the rotor core 34 at regular intervals in the circumferential direction.

The motor 30 shown in FIG. 8 can be used, for example, as a drive source for an electric pump mounted on a vehicle, more specifically, an electric pump (electric oil pump) that is attached to the transmission case of the vehicle and used to ensure the hydraulic pressure required inside the transmission by pumping oil to the transmission while the engine is stopped. Although not shown, when the motor 30 is used as a drive source for an electric oil pump, a pump rotor that can rotate integrally with the output shaft 33 is provided at the free end of the output shaft 33 outside the casing 31 .

Next, a motor stator 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic perspective view of a motor stator 1 (an assembly in which an insulating member and a bus bar are assembled to a stator core, which is a constituent member of the motor stator 1) before coil winding, FIG. 2 is a view of the motor stator 1 in FIG. 1 with the bus bar separated, and FIG.

The motor stator 1 includes a cylindrical stator core 2 made of a metal material (for example, an electromagnetic steel sheet) with excellent magnetic properties, a U-phase busbar 5, a V-phase busbar 6, a W-phase busbar 7 and a neutral point busbar (N-phase busbar) 8, an insulating member 10 made of an insulating material (here, a resin material), and a plurality of coils C.

The stator core 2 has a cylindrical portion 3 and radial teeth 4 protruding from the inner peripheral surface of the cylindrical portion 3 toward the center of the stator core 2. In this embodiment, a total of 12 teeth 4 are provided at equal intervals in the circumferential direction. In the following description, the twelve teeth 4 arranged in order along the circumferential direction will be referred to as the first tooth 4A to the twelfth tooth 4L (see FIG. 3). In FIG. 3, the first tooth 4A is arranged at the 12 o'clock position of the stator core 2, and thereafter, the remaining 11 teeth 4 (the second tooth 4B to the twelfth tooth 4L) are arranged in order at a pitch of 30° counterclockwise.

As described above, the motor stator 1 of this embodiment has a total of 12 teeth 4 (slots formed between the teeth 4), and the motor rotor 32 arranged radially inward of the motor stator 1 is provided with 10 permanent magnets 35 (see FIG. 8). Therefore, the motor stator 1 of this embodiment is a motor stator for a three-phase brushless motor with 10 poles and 12 slots. Such a brushless motor is a so-called fractional groove motor in which "the number of slots per pole per phase q" calculated by the formula q=N/(m×P) is not a positive integer but a fraction (=2/5), where N is the number of slots, m is the number of phases of the motor, and P is the number of permanent magnets (poles) provided in the motor rotor.

The insulating member 10 includes a first covering portion 11 that covers the inner peripheral surface of the cylindrical portion 3 of the stator core 2, a second covering portion 12 that covers the teeth 4 of the stator core 2 (more specifically, portions of the teeth 4 on which the coils 20 are wound), and a short cylindrical holding portion 13 that is provided at one end in the axial direction of the stator core 2 and holds the bus bars 5 to 8 in a non-contact state with each other.

The bus bars 5 to 8 are members that supply (distribute) the motor driving current output from an external power source (not shown) to the coil C. Therefore, the busbars 5 to 8 are all made of a highly conductive metal material such as copper or aluminum alloy.

As shown in FIG. 2, the U-phase bus bar 5 of the present embodiment is formed in a substantially circular arc shape as a whole, and is provided with a connection terminal 5a to which the coil wire CL is connected at one end in the longitudinal direction (circumferential direction), and an external connection terminal 5b connected to an external power supply at the other end in the longitudinal direction (circumferential direction). Like the U-phase bus bar 5, the V-phase bus bar 6 and the W-phase bus bar 7 are each formed in a generally arcuate shape as a whole, and are provided with

connection terminals

6a and 7a to which the coil wire CL is connected at one end in the circumferential direction, and

external connection terminals

6b and 7b to be connected to an external power supply at the other end in the circumferential direction. The U-phase bus bar 5, the V-phase bus bar 6, and the W-phase bus bar 7 are held by the holding portion 13 in a state in which the

terminals

5a, 6a, and 7a are exposed to the outside (projecting outward in the axial direction of the holding portion 13) and the

terminals

5b, 6b, and 7b project radially outward of the holding portion 13, as shown in FIG.

The neutral point bus bar 8 is an arc-shaped conductive member in which

connection terminals

8a, 8b, and 8c that form neutral points respectively with a U-phase coil portion 21, a V-phase coil portion 22, and a W-phase coil portion 23, which will be described later, are provided at intervals (see FIG. 2). Similarly to the U-phase bus bar 5, the neutral point bus bar 8 is also held by the holding portion 13 with the

terminals

8a, 8b, 8c exposed to the outside (protruding axially outward of the holding portion 13) (see FIG. 1).

As shown in FIGS. 1 to 2 and 5B, the connection terminals 5a of the U-phase bus bar 5 are substantially V-shaped with openings on both sides in the axial direction and circumferential direction. The

connection terminals

6a, 7a, 8a-8c of the other busbars 6-8 are also substantially V-shaped like the connection terminal 5a.

As shown in FIG. 3, the coil C is wound around each of a total of 12 teeth 4 (by so-called concentrated winding) via (the second covering portion 12 of) the insulating member 10 attached to the stator core 2. The coil C includes a total of four U-phase coils CU1 to CU4, a total of four V-phase coils CV1 to CV4, and a total of four W-phase coils CW1 to CW4, and these are star-connected using the bus bars 5 to 8 to form a motor drive circuit (power supply circuit) 20 as shown in FIGS.

A total of 12 coils C are formed by sequentially winding a single continuous coil wire (a conductive wire made of a metal material such as copper coated with an insulating film) CL around each of a total of 12 teeth 4 covered with (the second covering portion 12 of) an insulating member 10 by concentrated winding. In the present embodiment, as shown in FIGS. 6 and 7, the U-phase coil CU1 is first formed (wound), and thereafter, the coil C is wound in the order of CU2, CU3, CU4, CV3, CV4, CV1, CV2, CW1, CW2, CW3, and CW4. Specific examples of the coil winding process for winding the coil C around each tooth 4 and the wire connection process performed after the coil winding process are completed will be described below.

[Coil winding process]
As shown in FIG. 6, in this step, first, the coil wire CL is wound a predetermined number of times around the outer periphery of the first tooth 4A in the counterclockwise direction. As a result, the U-phase coil CU1 is wound around the outer periphery of the first tooth 4A by concentrated winding. The winding of the coil wire CL around the outer periphery of the first tooth 4A is started from one axial end side of the stator core 2 (the side where the holding portion 13 is provided, which is the upper side of the paper surface in FIG. 6; the same applies to the following description), and ends at the one axial end side of the stator core 2. That is, when the U-phase coil CU1 is wound around the first teeth 4A, both the winding start portion and the winding end portion of the coil wire CL are pulled out to one end side of the stator core 2 in the axial direction. The same applies when the remaining U-phase coils CU2-CU4, V-phase coils CV1-CV4, and W-phase coils CW1-CW4 are wound around the corresponding teeth. This is because the portions (connection wire portions CL ₁ to CL ₁₂ ) of the coil wire CL that are interposed between two coils adjacent to each other in the longitudinal direction to connect the two coils are arranged on one axial end side of the stator core 2 where the busbars 5 to 8 are provided, and predetermined connection wire portions are connected to the connection terminals of the corresponding busbars 5 to 8.

After winding the U-phase coil CU1, the coil wire CL is wound a predetermined number of times in the clockwise direction from one axial end side of the stator core 2 around the outer circumference of the second tooth 4B. As a result, the U-phase coil CU2 is wound around the outer periphery of the second tooth 4B by concentrated winding.

After winding the U-phase coil CU2, the coil wire CL is wound a predetermined number of times in the counterclockwise direction from one axial end of the stator core 2 to the outer periphery of the seventh tooth 4G. As a result, the U-phase coil CU3 is wound around the outer periphery of the seventh tooth 4G by concentrated winding. Before winding the coil wire CL around the outer circumference of the seventh tooth 4G, the connecting wire portion _CL2 of the coil wire CL that connects the U-phase coils CU2 and CU3 is wound around the connection terminal 5a of the U-phase bus bar 5 held by the holding portion 13. After winding the U-phase coil CU3, the coil wire CL is wound a predetermined number of times in the clockwise direction from one axial end side of the stator core 2 around the outer circumference of the eighth tooth 4H. As a result, the U-phase coil CU4 is wound around the outer periphery of the eighth tooth 4H by concentrated winding.

Here, in the implementation stage of the coil winding process, the busbars 5 to 8 may be held by the holding portion 13 so as not to be relatively movable with respect to the insulating member 10, or may be held by the holding portion 13 so as to be relatively movable with respect to the insulating member 10. The former configuration can be obtained, for example, by injection-molding the insulating member 10 (holding portion 13) with resin using the busbars 5 to 8 as insert parts. The latter configuration can be obtained, for example, by injection-molding the insulating member 10 (holding portion 13) shown in FIG. 2 having grooves 13a to 13d for fitting busbars with resin, and then outserting (fitting) the busbars 5 to 8 into the grooves 13a to 13d. With the latter configuration, the work of winding the coil wire around the connection terminals of the busbars performed in the coil winding process can be facilitated compared to the former configuration. When the latter configuration is adopted, relative movement of the busbars 5 to 8 with respect to the insulating member 10 can be restricted (busbars 5 to 8 fixed to the holding portion 13) by connecting coil wires to the connection terminals of each busbar.

After winding the U-phase coil CU4 (a total of four U-phase coils CU1 to CU4), the coil wire CL is wound from one end of the stator core 2 in the axial direction around the outer circumference of the ninth tooth 4I in the counterclockwise direction for a predetermined number of times. As a result, the V-phase coil CV3 is wound around the outer periphery of the ninth tooth 4I by concentrated winding. Before winding the coil wire CL around the outer circumference of the ninth tooth 4I, the connecting wire portion CL ₄ of the coil wire CL, which connects the U-phase coil CU4 and the V-phase coil CV3, is wound around the connection terminal 8a of the neutral point bus bar 8 held by the holding portion 13. After winding the V-phase coil CV3, the coil wire CL is wound a predetermined number of times clockwise around the outer circumference of the tenth tooth 4J from one end in the axial direction of the stator core 2 . As a result, the V-phase coil CV4 is wound around the outer circumference of the tenth tooth 4J by concentrated winding.

After winding the V-phase coil CV4, the coil wire CL is wound a predetermined number of times in the counterclockwise direction from one axial end of the stator core 2 to the outer periphery of the third tooth 4C. As a result, the V-phase coil CV1 is wound around the outer periphery of the third tooth 4C by concentrated winding. Before winding the coil wire CL around the outer circumference of the third tooth 4C, the connecting wire portion CL ₆ connecting the V-phase coils CV4 and CV1 of the coil wire CL is wound around the connection terminal 6a of the V-phase bus bar 6 held by the holding portion 13. After winding the V-phase coil CV1, the coil wire CL is wound a predetermined number of times clockwise from one axial end of the stator core 2 around the outer circumference of the fourth tooth 4D. As a result, the V-phase coil CV2 is wound around the outer periphery of the fourth tooth 4D by concentrated winding.

After winding the V-phase coil CV2 (four V-phase coils CV1 to CV4 in total), the coil wire CL is wound from one axial end of the stator core 2 around the outer periphery of the fifth tooth 4E in the counterclockwise direction for a predetermined number of times. As a result, the W-phase coil CW1 is wound around the outer periphery of the fifth tooth 4E by concentrated winding. Before winding the coil wire CL around the outer periphery of the fifth tooth 4E, the connecting wire portion CL ₈ of the coil wire CL, which connects the V-phase coil CV2 and the W-phase coil CW1, is wound around the connection terminal 8b of the neutral point bus bar 8 held by the holding portion 13. After winding the W-phase coil CW1, the coil wire CL is wound a predetermined number of times clockwise from one axial end of the stator core 2 to the outer periphery of the sixth tooth 4F. As a result, the W-phase coil CW2 is wound around the outer periphery of the sixth tooth 4F by concentrated winding.

After winding the W-phase coil CW2, the coil wire CL is wound a predetermined number of times in the counterclockwise direction from one end of the stator core 2 in the axial direction around the outer periphery of the eleventh tooth 4K. As a result, the W-phase coil CW3 is wound around the outer circumference of the eleventh tooth 4K by concentrated winding. Before the coil wire CL is wound around the outer periphery of the eleventh tooth 4K, the connecting wire portion _CL10 connecting the W-phase coils CW2 and CW3 of the coil wire CL is wound around the connection terminal 7a of the W-phase bus bar 7 held by the holding portion 13. After the W-phase coil CW3 is wound, the coil wire CL is wound a predetermined number of times clockwise around the outer periphery of the twelfth tooth 4L from one end in the axial direction of the stator core 2 . As a result, the W-phase coil CW4 is wound around the outer periphery of the twelfth tooth 4L by concentrated winding.

As described above, a total of four U-phase coils, a total of four V-phase coils, and a total of four W-phase coils are sequentially formed along the longitudinal direction of one continuous coil wire CL. A winding start portion (longitudinal end portion) CL _s and a winding end portion (longitudinal end portion) CL _f of a single continuous coil wire CL in which a total of 12 coils C are formed are both wrapped around a connection terminal 8 c of a neutral point bus bar 8 . As a result, the coil winding process of winding the coil C on each of the total 12 teeth 4 by concentrated winding is completed.

[Connection process]
In this connection step, the coil wire CL (the connecting wire portion thereof) that is bound by the connection terminals of the bus bars 5 to 8 is connected to the connection terminal that is bound. in particular,
- The connecting wire portion _CL2 of the coil wire CL is connected to the connection terminal 5a of the U-phase bus bar 5,
The connecting wire portion _CL6 of the coil wire CL is connected to the connection terminal 6a of the V-phase bus bar 6,
The connecting wire portion CL ₁₀ of the coil wire CL is connected to the connection terminal 7a of the W-phase bus bar 7,
- The connecting wire portion _CL4 of the coil wire CL is connected to the connection terminal 8a of the neutral point bus bar 8,
The connecting wire portion CL ₈ of the coil wire CL is connected to the connection terminal 8b of the neutral point bus bar 8,
The connecting wire portion CL ₁₂ (the start line CL _s and the finish line CL _f ) of the coil wire CL is connected to the connection terminal 8 c of the neutral point bus bar 8 .

Although not shown, the coil wire CL is connected by so-called fusing (thermal crimping) in which a pair of electrodes is compressed in the radial direction of the coil wire CL that is entwined with a V-shaped connection terminal, and current is passed between the pair of electrodes for a predetermined period of time. In the case of fusing, the conductor wire can be joined to the connection terminal at substantially the same time as the insulation film of the coil wire CL made of the conductor wire with the insulation film is removed, so that the coil wire CL can be connected efficiently.

The connection of the coil wire CL (the connecting wire portion thereof) to the six connection terminals may be performed individually or collectively. In addition, prior to performing the coil winding process described above, the insulating coating may be removed from the portion of the coil wire CL that is bound around the connection terminal (the planned connection portion to be connected to the terminal). In this case, in the connection step, for example, the coil wire CL can be connected to the connection terminal only by crimping the V-shaped connection terminal, and the coil wire CL can also be connected to the connection terminal by welding such as TIG welding or laser welding.

When the coil wire CL (the connecting wire portion) is connected to the connection terminals of the bus bars 5-8 in the above manner, as shown in FIG. 7, a U-phase coil portion 21 in which a total of four U-phase coils CU1-CU4 are connected in 2 parallel and 2 series, a V-phase coil portion 22 in which a total of 4 V-phase coils CV1 to CV4 are connected in 2 parallel and 2 series, and a total of 4 W-phase coils CW1 to CW4 are connected in 2 parallel and 2 series. A motor drive circuit 20 is obtained in which the W-phase coil portion 23 is connected to each other (star connection) using the bus bars 5-8.

In the U-phase coil section 21 of the present embodiment, a first row formed by connecting the U-phase coils CU1 and CU2 in series and a second row formed by connecting the U-phase coils CU3 and CU4 in series are connected in parallel by a connecting wire portion CL ₂ of the coil wire CL that connects the U-phase coils CU2 and CU3. In the V-phase coil section 22, a first row formed by connecting the V-phase coils CV3 and CV4 in series and a second row formed by connecting the V-phase coils CV1 and CV2 in series are connected in parallel by a connecting wire portion CL ₆ of the coil wire CL that connects the V-phase coils CV4 and CV1. In the W-phase coil section 23, a first row formed by connecting the W-phase coils CW1 and CW2 in series and a second row formed by connecting the W-phase coils CW3 and CW4 in series are connected in parallel by a connecting wire portion CL ₁₀ of the coil wire CL that connects the W-phase coils CW2 and CW3.

The motor stator 1 of the present embodiment is characterized in that it is possible to reduce the tensile force (in the axial direction) continuously acting on the

connection terminals

5a, 6a, 7a, and 8a-8c of the bus bars 5-8 as the coil wires CL (the crossover portions thereof) are entwined during the coil winding process. That is, as illustrated in FIG. 4, which is an enlarged view of the main part of FIG. 1, a relief portion 14 for relieving the tensile force described above is integrally provided in a short cylindrical holding portion 13 provided in the insulating member 10 on substantially the same phase as the connection terminal 5a of the U-phase bus bar 5. Although not shown in detail, among the holding portions 13, a relief portion 14 is also provided on substantially the same phase as the phase where the connection terminal 6a of the V-phase bus bar 6, the connection terminal 7a of the W-phase bus bar 7, and the connection terminals 8a to 8c of the neutral point bus bar 8 are arranged.

The relief portion 14 of the present embodiment shown in FIG. 4 has a support portion 15 extending axially outward from the end surface of the holding portion 13, and a first projection 16 and a second projection 17 which are provided separately from each other (spaced apart from each other in the axial direction and the circumferential direction in the illustrated example) and protrude radially outward from the outer diameter surface of the support portion 15. Each of the first projection 16 and the second projection 17 is provided such that at least a portion thereof is arranged within the range of a projection plane P obtained by projecting the corresponding wiring terminal (here, the wiring terminal 5a of the U-phase bus bar 5) in the axial direction.

In the present embodiment in which the relief portion 14 having the above configuration is provided, when the coil wire CL (the crossover portion CL ₂ of the coil wire CL that connects the U-phase coils CU2 and CU3) is wrapped around the corresponding connection terminal (connection terminal 5a of the U-phase bus bar 5), the coil wire CL is also wrapped around the first projection 16 and the second projection 17 that form the relief portion 14.

Specifically, as shown in FIGS. 5A and 5B, the coil wire CL is entwined around the first projection 16 by changing the advancing direction of the coil wire CL (indicated by the solid arrow in FIG. 5A) arranged in the gap (passage) defined between the end surfaces of the holding portion 13 and the first projection 16 facing each other in the axial direction from the circumferential direction to the axially outward direction. Next, the traveling direction of the coil wire CL arranged in the inner passage of the connection terminal 5a is changed from the circumferential direction to the axially inward direction, and the traveling direction of the coil wire CL is changed from the axially inward direction to the circumferential direction so that the coil wire CL is arranged in the passage defined between the first projection 16 and the second projection 17, thereby entangling the coil wire CL around the connection terminal 5a and the second projection 17.

Although the detailed explanation is omitted, when the coil wire CL (the crossover portion) corresponding to the connection terminal 6a of the V-phase bus bar 6, the connection terminal 7a of the W-phase bus bar 7, and the connection terminals 8a to 8c of the neutral point bus bar 8 is entwined, the coil wire CL is also entwined with the first projection 16 and the second projection 17 of the relaxation portion 14 provided corresponding to each of the above-mentioned connection terminals.

As described above, in the motor stator 1 of the present embodiment, the coil wire CL (the connecting wire portion thereof) drawn out from the coil C is connected to the connection terminals in a state of being entwined with the connection terminals of the bus bars 5 to 8 held by the holding portion 13 of the insulating member 10. Such a configuration can be obtained by entangling the planned connection points of the coil wire CL with respect to the connection terminals when winding the coil C, and then connecting the planned connection points of the coil wire CL to the corresponding connection terminals. In short, in the motor stator 1 of the present embodiment, the connection operation of the coil wire CL can be performed in a state in which the planned connection locations of the coil wire CL are positioned with respect to the connection terminals. Therefore, it is possible to smoothly perform the connection operation of the coil wire CL with respect to the connection terminals while preventing deterioration in the shape accuracy of the coil C as much as possible.

However, when the coil wire CL is entwined with the connection terminals of the busbar, the resulting tensile force will continue to act on the connection terminals, so there is a possibility that the connection terminals will be deformed or damaged, making it impossible to maintain an appropriate connection state. In this respect, in the motor stator 1 of the present embodiment, since the holding portion 13 of the insulating member 10 is provided with the relief portion 14 that relieves the tensile force, it is possible to prevent such a problem from occurring as much as possible.

In particular, when the relief portion 14 having the first projection 16 and the second projection 17 provided separately from each other is adopted as in the present embodiment, the portions of the coil wire CL located upstream and downstream of the portion connected (entwined) to the connection terminal can be easily entwined with the first projection 16 and the second projection 17, respectively, so that the tensile force acting on the connection terminal can be effectively alleviated. In addition, in the present embodiment, at least a part of the first projection 16 and the second projection 17 are arranged in the projection plane P obtained by projecting the corresponding wiring terminal in the axial direction, so the tensile force relaxation ability can be enhanced from this point as well. Further, in the present embodiment in which the relief portion 14 is provided integrally with the holding portion 13 made of resin, the first projection 16 and the second projection 17 that constitute the relief portion 14 can be injection molded with resin. At this time, if both

protrusions

16 and 17 are spaced apart from each other in the circumferential direction, there is also the advantage that the mold splitting can be simplified and the molding cost can be reduced.

In addition, in the motor stator 1 of the present embodiment, a total of four bus bars 5 to 8 are held by the holding portion 13 of the insulating member 10 arranged on one axial end side of the stator core 2 in a non-contact state. This means that the insulating member 10 for insulating between the teeth 4 and the coil C wound thereon integrally has a portion corresponding to the busbar holder of the conventional busbar unit. In this case, there is no need to provide a busbar unit separately from the motor stator 1, so the number of parts can be reduced.

By the way, when forming the drive circuit (star connection) for the 10-pole, 12-slot three-phase brushless motor described above, there are a maximum of 12 connection points for a total of four busbars (U-phase busbar, V-phase busbar, W-phase busbar, and neutral point busbar). On the other hand, if the motor drive circuit 20 is formed in which a total of 12 coils C are star-connected in the manner described above, the number of connection points for the total of four bus bars 5 to 8 can be reduced to six. As a result, the cost of the motor stator 1 can be further reduced through the simplification of the wire connection work.

Combined with the effects described above, according to the present invention, it is possible to provide the motor stator 1 with excellent shape accuracy of each coil C and capable of stably exhibiting a predetermined output at a low cost.

Although the motor stator 1 according to the embodiment of the present invention has been described above, the motor stator 1 can be appropriately modified as long as the gist of the present invention is not changed. For example, in the embodiment described above, a total of 12 coils C are formed on a single coil wire CL by sequentially winding a single continuous coil wire CL around a total of 12 teeth 4 by concentrated winding, but the number of coils C formed on a single coil wire CL can be arbitrarily selected. However, in order to reduce the cost of the motor stator 1, it is preferable to reduce the number of connecting points of the coil wire CL to the busbars 5 to 8 as much as possible. Therefore, when it is important to reduce the cost of the motor stator 1, it is preferable to form a plurality of coils C by sequentially intensive winding one continuous coil wire CL around each of a plurality of teeth.

In the above description, as the relief portion 14, the supporting portion 15 provided with the two

projections

16 and 17 spaced apart from each other in the axial direction was adopted, but the supporting portion 15 may have one or three or more projections.

In the above description, the case where the present invention is applied to the stator 1 for a three-phase brushless motor (fractional groove motor) with 10 poles and 12 slots has been described. In the latter case, for example, a motor drive circuit is formed by star-connecting U-phase to W-phase coils connected in two parallel and three series. The present invention can also be applied to a motor stator in which U-phase coils, V-phase coils, and W-phase coils are delta-connected using bus bars.

The present invention is by no means limited to the embodiments described above, and it goes without saying that it can be embodied in various forms without departing from the gist of the present invention. The scope of the present invention is indicated by the claims, and includes equivalent meanings and all changes within the scope of the claims.

1 Motor Stator 2 Stator Core 4 Teeth 5 U-phase Busbar 5a Connection Terminal 6 V-phase Busbar 6a Connection Terminal 7 W-phase Busbar 7a Connection Terminal 8

Neutral Point Busbar

8a, 8b, 8c Connection Terminal 10 Insulating Member 13 Holding Part 14 Relieving Part 16 First Projection 17 Second Projection 20 Motor Drive Circuit 3 0 motor 32 motor rotor 33 output shaft 35 permanent magnet C coil CL coil wire

Claims

A motor stator comprising a cylindrical stator core, coils wound around radial teeth provided on the stator core via an insulating member, and bus bars having connection terminals and external connection terminals,
The insulating member has a holding portion that holds the busbar on one axial end side of the stator core,
a coil wire drawn out from the coil to one axial end side of the stator core is connected to the connection terminal in a state of being entwined with the connection terminal of the bus bar;
A motor stator according to claim 1, wherein the holding portion is provided with a relief portion that relieves a tensile force acting on the connection terminal due to the winding of the coil wire around the connection terminal.
The relief portion has a first projection and a second projection provided separately from each other,
2. The motor stator according to claim 1, wherein portions of the coil wire located upstream and downstream of the portion connected to the connection terminal are respectively wound around the first projection and the second projection.
3. The motor stator according to claim 2, wherein at least a part of the first projection and the second projection is arranged within a plane of projection of the terminal for connection in the axial direction.
The motor stator according to any one of claims 1 to 3, wherein the coil wire is connected to the connection terminal by fusing.
A plurality of the teeth and the coil wound thereon are provided at intervals in the circumferential direction,
5. The motor stator according to any one of claims 1 to 4, wherein a plurality of said coils are formed by sequentially intensively winding one continuous coil wire around each of said plurality of teeth.
The motor stator according to any one of claims 1 to 5, which is for a three-phase brushless motor with 10 poles and 12 slots.
A motor comprising the motor stator according to any one of claims 1 to 6 and a motor rotor.