WO2013154054A1 - Brushless motor - Google Patents

Abstract

A bus bar unit (50) of this brushless motor (1) is provided with a plurality of curved phase bus bars which are provided for respective phases and each have a phase terminal connected to one end of a coil (12), and a ring-shaped bus bar holder (51) which is produced from an insulating material and holds the plurality of phase bus bars. The inner diameter (E1) of the bus bar holder (51) is set larger than the diameter (E2) of the outer peripheral surface of an insulator (11), and the bus bar unit (50) is disposed radially outside the insulator (11).

Description

Brushless motor

The present invention relates to a brushless motor used in, for example, a motorcycle.
This application claims priority based on Japanese Patent Application No. 2012-092148 for which it applied to Japan on April 13, 2012, and uses the content here.

Generally, an inner rotor type brushless motor has a stator that is fitted and fixed to a motor case, and a rotor that is disposed at the center in the radial direction of the motor case and is rotatably supported with respect to the stator. A plurality of permanent magnets are provided on the outer peripheral surface of the rotor. The stator includes a substantially cylindrical stator core and a plurality of teeth projecting radially inward from the stator core.

Each tooth is provided with a resin insulator, which is an electrically insulating material, and a coil is wound through the insulator. When power from an external power source is supplied to the coil, an attractive force or a repulsive force is generated between the magnetic flux generated in the coil and the permanent magnet, and the rotor rotates.

Here, as a means for supplying power to the coil, a state in which a plurality of metal bus bars are electrically insulated from each other in a resin mold body formed in a substantially annular shape in order to reduce the size and improve the assemblability. In some cases, a bus bar unit embedded in (1) is used.

The bus bar unit described in Patent Document 1 is laminated in such a state that a flat-phase bus bar (three phases of U phase, V phase, and W phase) and a neutral point bus bar are separated in the axial direction. Molded by the body. The outer peripheral surface of the resin mold body is integrally formed with a leg portion protruding toward the stator core side, while the insulator is formed with a concave portion capable of fitting the leg portion at a portion corresponding to the leg portion. . The bus bar unit is fixed by stacking the bus bar unit on the insulator so that the leg portion is fitted in the recess.

In addition, each phase terminal projecting from each phase bus bar and each neutral point terminal projecting from the neutral point bus bar are directed radially outward from the outer peripheral surface of the resin mold body. And projecting radially.
Each phase terminal is connected to the winding start end of each phase coil, while the neutral point terminal is connected to the winding end of each phase coil. Thereby, each phase coil is connected by what is called a star connection system.

JP 2010-233327 A

By the way, there is a high demand for further miniaturization and weight reduction of the brushless motor described above. In particular, in a motorcycle, since the vehicle body is inclined, it is desired to shorten the shaft of a brushless motor mounted on the motorcycle in consideration of an inclination angle (bank angle) toward the vehicle body side.
However, in the above-described prior art, since the bus bar unit is fixed so as to overlap the bus bar unit on the insulator, it is difficult to suppress the height from the stator core to the bus bar unit. For this reason, the axial length of a brushless motor becomes long and there exists a subject that it will enlarge.

Therefore, the present invention has been made in view of the above-described circumstances, and provides a brushless motor that can be reduced in size.

According to the first aspect of the present invention, a brushless motor includes a stator core, a rotor that is disposed radially inside the stator core, and is rotatably supported with respect to the stator core, and the stator core via an insulator. A plurality of wound coils of a phase are provided with a ring-shaped bus bar unit for supplying power. The bus bar unit is provided for each phase, and includes a plurality of curved phase bus bars having phase terminals connected to one end of the coil, and a ring-shaped bus bar made of an insulating member that holds the plurality of phase bus bars. A holder. The diameter of the inner peripheral surface of the bus bar holder was set to be larger than the diameter of the outer peripheral surface of the insulator, and the bus bar unit was arranged on the outer side in the radial direction than the insulator.

By comprising in this way, an insulator and a bus-bar unit can be wrapped in an axial direction. For this reason, the height from the stator core to the bus bar unit can be suppressed correspondingly, and as a result, the axial length of the brushless motor can be shortened, and the brushless motor can be miniaturized.
In addition, since the bus bar unit is disposed on the radially outer side of the insulator, it is easy to secure a space above the stator core in the axial direction, and the heat dissipation effect of the heat generated by the coil can be enhanced. For this reason, the temperature rise of a brushless motor can be suppressed and it becomes possible to raise the motor efficiency of a brushless motor.
Furthermore, if a space can be secured above the stator core in the axial direction, it is possible to draw the terminal portion of the coil into this space and connect the terminal portion of the coil and each terminal of the bus bar unit. For this reason, the routing route of the terminal part of a coil can be simplified.

According to the second aspect of the present invention, the plurality of phase bus bars are formed by curving the thickness direction of the strip-shaped metal plate, and the respective phase bus bars are arranged side by side in the radial direction. At least one of the bus bars for each phase is formed such that the radius of curvature changes from the middle in the circumferential direction.

By configuring in this way, it is possible to suppress the formation of an extra space between the radial directions of the plurality of phase bus bars. For this reason, the radial direction of the bus bar unit can be reduced, and as a result, the brushless motor can be reduced in size.

According to the third aspect of the present invention, the bus bar holder has a holder body formed in a ring shape. A plurality of grooves into which the plurality of phase bus bars can be inserted from one side in the axial direction are formed in the holder body side by side in the radial direction. At least a part of the opening edge of each groove is formed with a retaining claw for preventing the plurality of phase bus bars from coming off.

By comprising in this way, since the several phase bus bar is not molded by the resin mold body like the past, the large installation for molding becomes unnecessary. For this reason, the equipment for manufacturing the bus bar unit can be simplified, and the manufacturing cost of the bus bar unit can be reduced.
Further, it is possible to prevent each phase bus bar from coming out of the groove without managing the dimensional tolerance between each groove and the plurality of phase bus bars with high accuracy. For this reason, the manufacturing cost of a bus-bar unit can be reduced.
Furthermore, it is possible to reliably hold each phase bus bar as compared to the case where the shape of the plurality of phase bus bars is different from the shape of the groove and is held by the elasticity of each phase bus bar.

According to the fourth aspect of the present invention, the two coils are wound around the teeth of the stator core so as to form a parallel circuit.
By comprising in this way, the total resistance of the coil wound around each tooth can be suppressed while reducing the wire diameter of the coil. For this reason, winding work can be facilitated as much as the diameter of the coil can be reduced.

According to a fifth aspect of the present invention, the bus bar unit includes a grommet, and the grommet is formed from one plane of the grommet, and has a gasket circulation hole for injecting a liquid sealing material, and the other grommet. And a gasket retaining groove that is formed over the entire area and communicates with the gasket circulation hole.
With this configuration, when the liquid sealing material is injected into the gasket circulation hole, the liquid sealing material is filled into the gasket retaining groove through the gasket circulation hole. Therefore, even when the liquid sealing material is applied to the other plane of the grommet after the grommet is assembled at a predetermined position, the liquid sealing material can be distributed to the other plane of the grommet.

According to the above brushless motor, the insulator and the bus bar unit can be wrapped in the axial direction. For this reason, the height from the stator core to the bus bar unit can be suppressed correspondingly, and as a result, the axial length of the brushless motor can be shortened, and the brushless motor can be miniaturized.

It is sectional drawing of the brushless motor in embodiment of this invention. It is a top view in the state where a bracket of a brushless motor in an embodiment of the present invention was removed. It is a top view of the split core in the embodiment of the present invention. It is explanatory drawing which shows the winding method of the coil to the teeth part of each division | segmentation core in embodiment of this invention. It is explanatory drawing which shows the winding method of the coil to the teeth part of each division | segmentation core in embodiment of this invention. It is a top view of the bus-bar unit in the embodiment of the present invention. It is a top view of the bus bar for U phases in the embodiment of the present invention. It is a top view of the bus bar for V phases in the embodiment of the present invention. It is a top view of the bus bar for W phases in the embodiment of the present invention. It is a top view of the bus bar for connection in the embodiment of the present invention. It is a perspective view of the bus bar for neutral points in the embodiment of the present invention. It is an expansion perspective view of the A section of FIG. It is the top view which looked at the A section of FIG. 6 from the back side. It is a connection diagram of the coil in the embodiment of the present invention. It is a top view of the grommet in the modification of the embodiment of the present invention.

(Brushless motor)
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view including the central axis O of the brushless motor 1.
As shown in FIG. 1, a brushless motor 1 is used in, for example, an electric motorcycle, and is provided so as to be rotatable with respect to a stator 3 press-fitted into a bottomed cylindrical stator housing 2 and the stator 3. The rotor 4, the bus bar unit 50 for supplying current to the coil 12 wound around the stator 3, and the bracket 7 provided so as to close the opening 2a of the stator housing 2. ing.

A boss 2c that protrudes outward in the axial direction is formed at the center in the radial direction on the bottom 2b of the stator housing 2, and a bearing 5 is press-fitted therein. The bearing 5 is for rotatably supporting the rotating shaft 6 of the rotor 4.
In the following description, the opening side (left side in FIG. 1) of the stator housing 2 may be described as one side in the axial direction, and the bottom 2b side (right side in FIG. 1) may be described as the other side in the axial direction.

FIG. 2 is a plan view of the brushless motor 1 with the bracket 7 removed, and FIG. 3 is a plan view of the split core 61.
As shown in FIGS. 1 to 3, the stator 3 has a substantially cylindrical stator core 10, and the outer peripheral surface of the stator core 10 is press-fitted into the inner peripheral surface of the cylindrical portion 2 d of the stator housing 2.
Here, the stator core 10 uses a split core system that can be split in the circumferential direction. The divided core 61 divided from the stator core 10 is formed by, for example, laminating a plurality of plate materials made of a magnetic material in the axial direction, and has a core body 62 extending in the circumferential direction. The core body 62 is a portion that forms an annular magnetic path of the stator core 10 and is a portion that is fitted into the inner peripheral surface of the stator housing 2, and is formed in a substantially arc shape in an axial plan view. .

Both end portions in the circumferential direction of the core body 62 are connection portions 63a and 63b that are connected to the other core body 62 by press-fitting. One connecting portion 63a has a convex shape, and the other connecting portion 63b has a concave shape that can receive one connecting portion 63a. Thereby, it is possible to form the substantially cylindrical stator core 10 by connecting the core bodies 62.
On the inner peripheral side of each core body 62, a tooth portion 64 is integrally extended from the substantially central portion in the circumferential direction toward the center of rotation so as to extend along the radial direction. Each tooth portion 64 is formed in a substantially T shape in a plan view in the axial direction, and includes a winding drum portion 65a extending in the radial direction and an inner peripheral portion 65b extending in the circumferential direction.

A coil 12 is wound around the winding body 65a via an insulator 11. The insulator 11 is an insulating material for insulation between the tooth portion 64 and the coil 12. The insulator 11 is formed to rise from a base portion 11a that covers the outer peripheral surface of the winding drum portion 65a, an inner peripheral wall portion 11b that rises from a radially inner edge of the base portion 11a, and a radially outer edge of the base portion 11a. The outer peripheral wall portion 11c is integrally formed. The coil 12 is wound so as to be housed in a concave coil housing portion 11d formed by the base portion 11a, the inner peripheral wall portion 11b, and the outer peripheral wall portion 11c.

Here, each tooth portion 64 is assigned three phases of U phase, V phase, and W phase so that two teeth portions 64 adjacent in the circumferential direction are in phase, and the coil 12 is wound. It corresponds to the phase of the tooth portion 64 that is made. That is, the brushless motor 1 of this embodiment is a three-phase brushless motor including three-phase coils 12 of a U phase, a V phase, and a W phase.
The brushless motor 1 of this embodiment employs so-called double winding in which two coils 12 are wound around each tooth portion 64 and the ends of the two coils 12 are connected to each other. This double winding method will be described in detail below.

(Coil winding method)
4 and 5 are explanatory views showing a method of winding the coil 12 around the tooth portion 64 of each divided core 61, and are perspective views of the divided core 61.
Here, in the following description, it is assumed that the number of turns of the coil 12 to each tooth portion 64 is 28 times. That is, as shown in FIG. 3, the coil 12 passes 28 times on one side in the radial direction of the tooth portion 64, in other words, the coil 12 passes 56 times in total on both radial sides of the tooth portion 64. become. In FIG. 3, numbers are assigned to the coils 12 that pass through both radial side surfaces of the tooth portion 64.

As described above, when the coil 12 passes through the radial side surface of the tooth portion 64 a total of 56 times, a loop portion 12a is formed between the 28th coil 12 and the 29th coil 12 as shown in FIG. . And the coil 12 after the 29th time is wound around the teeth part 64 again as usual.
After the coil 12 is wound 56 times around the tooth portion 64, the loop portion 12a is cut as shown in FIG. And while connecting the terminal part of the 28th coil 12 formed by cutting to the terminal part of the first coil 12, the terminal part of the 29th coil 12 is connected to the terminal part of the 56th coil 12 Connect to. Thereby, winding of the coil 12 to the teeth part 64 is completed.

In this way, the loop portion 12a is formed in the coil 12 in the middle of winding around the tooth portion 64 (between the 28th and 29th times in the present embodiment), and then the loop portion 12a is cut, thereby forming the teeth. While the coil 12 is continuously wound around the portion 64, double winding can be performed. That is, the first to 28th coils 12 become the first (first layer) coil 12 (see X1 in FIG. 3), and the 29th to 56th coils 12 are the second (second layer). The coil 12 is obtained (see the X2 part in FIG. 3).

Returning to FIG. 1 and FIG. 2, the rotor 4 includes a rotating shaft 6, a rotor core 41 that is fitted and fixed to the rotating shaft 6, and a magnet 13 that is disposed in the rotor core 41 along the circumferential direction. .
The rotating shaft 6 is rotatably supported at both ends by a bearing 5 provided on the bottom 2 b of the stator housing 2 and a bearing 21 provided on the bracket 7.

The rotor core 41 is formed by laminating a plurality of electromagnetic steel plates formed in a substantially disc shape along the central axis O, and has a press-fit hole 43 into which the rotary shaft 6 can be press-fitted in the center in the radial direction. Is formed. Further, the axial length of the rotor core 41 is set to be substantially the same as the axial length of the stator core 10. Further, a plurality of slits 44 penetrating in the axial direction are formed in the outer circumferential portion of the rotor core 41 at equal intervals in the circumferential direction. In these slits 44, the magnet 13 is inserted and fixed.

The magnet 13 is a permanent magnet made of segmented neodymium or the like formed in a block shape, and is arranged in the slit 44 so that the magnetic poles change in the circumferential direction in order. The length of the magnet 13 in the axial direction is set to substantially match the length of the rotor core 41 in the axial direction.

With such a configuration, the brushless motor 1 generates a magnetic field in the stator core 10 by supplying current supplied from an external power source to the coils 12 of each phase via the bus bar unit 50. ing. The rotor 4 is rotated by the attractive force and the repulsive force between the magnetic field and the magnet 13.

(Bus bar unit)
FIG. 6 is a plan view of the bus bar unit 50. In FIG. 6, the front side of the drawing is the one side (left side in FIG. 1) of the stator housing 2.
As shown in FIGS. 1 and 6, the bus bar unit 50 connects the coils 12 of each phase by a so-called star connection method, and electrically connects the coils 12 of each phase and an external power source (not shown). belongs to. The bus bar unit 50 is formed in a substantially ring shape, and is disposed coaxially with the stator core 10 on one side of the stator core 10.

Further, as shown in FIG. 6, the bus bar unit 50 includes each phase bus bar (U-phase bus bar 30U, V-phase bus bar 30V, W-phase bus bar 30W) connected to one terminal portion of each phase coil 12. ), And the neutral point bus bar 30N connected to the other terminal portion of the coil 12 of each phase, and the phase bus bars 30U, 30V, 30W and the neutral point bus bar 30N are arranged side by side in the radial direction. And a bus bar holder 51 that holds the head in a state where it is in contact.

(U-phase bus bar)
Next, the respective phase bus bars (U-phase bus bar 30U, V-phase bus bar 30V, W-phase bus bar 30W) will be described with reference to FIGS.
FIG. 7 is a plan view of the U-phase bus bar 30U.
As shown in the figure, the U-phase bus bar 30U is obtained by stamping a strip-shaped metal plate made of copper or the like by pressing or the like, and is curved so that the thickness direction thereof follows the opening 2a of the stator housing 2. The bus bar main body 31U is formed in a substantially arc shape.

More specifically, the bus bar main body 31U is curved so as to have a substantially semicircular shape, and its radius of curvature changes with the substantially center in the extending direction as a boundary. That is, the bus bar main body 31U is formed by continuously forming a first main body 131U having a radius of curvature R1 and a second main body 231U having a radius of curvature R2. Here, the radius of curvature R1 and the radius of curvature R2 are
R1> R2 (1)
It is set to satisfy.

In addition, U-phase terminals 35U are formed in the bus bar main body 31U at positions corresponding to the two locations from which the terminal portions of the U-phase coil 12 are drawn, respectively. That is, one U-phase terminal 35U is formed on one end side of the first main body 131U of the bus bar main body 31U and one end side of the second main body 231U.
The U-phase terminal 35U is for connecting the U-phase bus bar 30U and the terminal portion of the U-phase coil 12. The U-phase terminal 35U is integrally formed with a tongue piece portion 36U that is bent from one axial side of the bus bar main body 31U toward the inside in the radial direction, and a coil holding portion 37U provided at the tip of the tongue piece portion 36U. Has been.

The coil holding portion 37U is formed in a substantially U shape so that the terminal portion of the U-phase coil 12 can be fixed by caulking. And the coil holding | maintenance part 37U is arrange | positioned so that the terminal part of the coil 12 can be received from the circumferential direction, and the terminal part of the coil 12 can be penetrated along an axial direction.
In addition, after crimping and fixing the terminal part of the coil 12 to the coil holding part 37U, the coil holding part 37U and the terminal part of the coil 12 may be welded to further strengthen the connection between the two parts 37U and 12. it can.

In addition, a power feeding portion 39U that is bent and extended from one axial side toward the radially outer side is integrally formed at one end of the first main body 131U of the bus bar main body 31U. The power feeding unit 39U is electrically connected to the terminal 23 (see FIG. 1). The terminal 23 is connected to an external power supply (not shown) so that the current of the external power supply can be supplied to the U-phase bus bar 30U.

(V-phase bus bar)
FIG. 8 is a plan view of the V-phase bus bar 30V.
As shown in the figure, the V-phase bus bar 30V has a bus bar body 31V that is curved so as to have a substantially semicircular shape. The bus bar body 31V has a radius of curvature that is substantially in the center in the extending direction. And the first main body 131V and the second main body 231V are formed continuously, and the first main body 131V so as to correspond to the position where the terminal portion of the V-phase coil 12 is pulled out. In addition, the basic configuration, such as the point that one V-phase terminal 35V is formed for each of the second main bodies 231V, and the power feeding portion 39V that connects the terminal 23 to the bus bar main body 31V, are integrally formed. It is the same as U-phase bus bar 30U (the same applies to W-phase bus bar 30W below).

Here, the difference between the V-phase bus bar 30V and the U-phase bus bar 30U is that the curvature radius of the bus bar body 31V in the V-phase bus bar 30V is different from the curvature radius of the bus bar body 31U in the U-phase bus bar 30U. And the position of the power feeding unit 39V with respect to the bus bar main body 31V and the position of the power feeding unit 39U with respect to the bus bar main body 31U are different (the same applies to the W-phase bus bar 30W below).

That is, in the bus bar body 31V, the curvature radius of the first body 131V is set to R3, while the curvature radius of the second body 231V is set to R4. The curvature radius R3 and the curvature radius R4 are
R2≈R3≈R4 (2)
It is set to satisfy.

In addition, the power feeding portion 39V integrally formed with the bus bar main body 31V is disposed so as to be adjacent to the power feeding portion 39U of the U-phase bus bar 30U and at the substantially center in the extending direction of the bus bar main body 31V. . In other words, the power feeding unit 39V is disposed in the vicinity of the connection portion between the first main body 131V and the second main body 231V.

(W-phase bus bar)
FIG. 9 is a plan view of the W-phase bus bar 30W.
As shown in the figure, the radius of curvature of the first main body 131W constituting one of the bus bar main bodies 31W of the W-phase bus bar 30W is set to R5. Further, the radius of curvature of the second main body 231W constituting the other side of the bus bar main body 31W is set to R6. And these curvature radius R5 and curvature radius R6 are:
R1≈R5≈R6 (3)
It is set to satisfy.

The two W-phase terminals 35W are provided on one end side of the first main body 131W and one end side of the second main body 231W, respectively. Furthermore, the power feeding unit 39W is disposed at one end of the first main body 131W.

Here, the U-phase bus bar 30U and the W-phase bus bar 30W are substantially symmetrical with respect to the rotation shaft 6 and a straight line L1 passing through the center of the power feeding portion 39V of the V-phase bus bar 30V. .
In addition, each phase bus bar 30U, 30V, 30W has a connection bus bar 30J for connecting in series the coils 12 of the same phase adjacent in the circumferential direction.

(Connection bus bar)
FIG. 10 is a plan view of the connecting bus bar 30J.
As shown in the figure, the basic configuration of the connection bus bar 30J is the same as that of the above-described phase bus bars 30U, 30V, 30W. That is, the connecting bus bar 30J has a bus bar main body 31J formed by continuously forming a first main body 131J and a second main body 231J.
The bus bar main body 31J extends so as to straddle the terminal portions on the side where the adjacent in-phase coils 12 are connected in series.

The radius of curvature of the first main body 131J is set to R7, while the radius of curvature of the second main body 231J is set to R8. And these curvature radius R7 and curvature radius R8 are:
R7≈R8 (4)
And the size is set so as not to interfere with the bus bar main bodies 31U, 31V, 31W in a state where the bus bars for the phases 30U, 30V, 30W are arranged in the radial direction.

Furthermore, connection terminals 35J are formed at both ends of the bus bar main body 31J in the extending direction, that is, at one end of the first main body 131J and one end of the second main body 231J, respectively. Here, since the configuration of the connection terminal 35J is the same as that of the phase terminals 35U, 35V, and 35W, detailed description thereof is omitted.

(Neutral point bus bar)
Next, the neutral point bus bar 30N will be described with reference to FIG.
FIG. 11 is a perspective view of the neutral point bus bar 30N.
As shown in the figure, the neutral point bus bar 30N is formed by punching a band-shaped metal plate made of copper or the like by pressing or the like, as with each phase bus bar 30U, 30V, 30W. The bus bar main body 31N is formed in a substantially annular shape with a curved direction. The radius R9 of the bus bar body 31N is
R7 <R9 (5)
R8 <R9 (6)
It is set to satisfy.

Further, neutral point terminals 35N are formed in the bus bar main body 31N at positions corresponding to the terminal portions on the side connected as the neutral points of the coils 12 of the respective phases. That is, in this embodiment, six neutral point terminals 35N are formed on the bus bar main body 31N.
Here, since the configuration of the neutral point terminal 35N is the same as that of the phase terminals 35U, 35V, and 35W, detailed description thereof is omitted.

(Bus bar holder)
Next, the bus bar holder 51 will be described with reference to FIGS. 1, 6, 12, and 13. 12 is an enlarged perspective view of a portion A in FIG. 6, and FIG. 13 is a plan view of the portion A in FIG. 6 as viewed from the back side.
As shown in FIGS. 1 and 6, the bus bar holder 51 has a holder main body 52 that can accommodate the bus bars 30U, 30V, 30W for each phase including the connection bus bar J and the bus bar 30N for the neutral point. .

The holder body 52 is formed in a substantially ring shape by an insulating member such as resin. In the holder main body 52, the bus bar main bodies 31U, 31V, 31W, 31J, 31N of the respective phase bus bars 30U, 30V, 30W including the connection bus bar 30J and the neutral point bus bar 30N are inserted from one side in the axial direction. Possible groove portions 53U, 53V, 53W, 53J, 53N are formed. That is, each of the groove portions 53U, 53V, 53W, 53J, and 53N is formed so as to open on one side in the axial direction.

Further, on the outer peripheral edge of the holder main body 52, a pedestal portion 55 on which the power feeding portions 39U, 39V, 39W of the respective phase bus bars 30U, 30V, 30W can be placed is formed extending outward in the radial direction. The pedestal portion 55 is formed in a substantially rectangular shape so as to be long in the circumferential direction in the plan view in the axial direction. The power feeding portions 39U, 39V, 39W are arranged in parallel in the order of the U phase, the V phase, and the W phase along the longitudinal direction of the pedestal portion 55, that is, the circumferential direction of the holder main body 52.

The groove portions 53U, 53V, 53W, 53J, and 53N are formed such that the power feeding portions 39U, 39V, and 39W are arranged in parallel in the order of the U phase, the V phase, and the W phase. That is, six groove portions 53J into which the bus bar main body 31J of the connection bus bar 30J can be inserted are formed on the innermost peripheral side of the holder main body 52. Further, a groove 53N into which the bus bar main body 31N of the neutral point bus bar 30N can be inserted is formed on the outer side in the radial direction than the groove 53J. Further, a groove 53V into which the bus bar main body 31V of the V-phase bus bar 30V can be inserted is formed on the outer side in the radial direction than the groove 53N. A groove 53U into which the bus bar main body 31U of the U-phase bus bar 30U can be inserted and a groove 53W into which the bus bar main body 31W of the W-phase bus bar 30W can be inserted are formed radially outward from the groove 53V. .

Here, as shown in detail in FIGS. 12 and 13, a part of the opening edge of each of the grooves 53U, 53V, 53W, 53J, and 53N is provided in each phase from each of the grooves 53U, 53V, 53W, 53J, and 53N. The retaining claws 57a and 57b for preventing the bus bars 30U, 30V, 30W for connection, the bus bar 30J for connection, and the bus bar 30N for neutral point from coming off are formed.
On the other side in the axial direction of the portion where the retaining claws 57a, 57b of the holder body 52 are formed, a die-cutting hole 58 (not shown) is formed. By using the punching hole 58, the undercut portions (not shown) of the retaining claws 57a and 57b can be easily formed. Thereby, the manufacturing cost of the holder main body 52 can be reduced.

Thus, by forming the groove portions 53U, 53V, 53W, 53J, 53N in the holder main body 52, the holder main body 52 has the connecting bus bar 30J, the neutral point bus bar 30N, and the V phase in order from the radially inner side. The bus bar 30V is disposed, and the U-phase bus bar 30U and the W-phase bus bar 30W are disposed on the outermost peripheral side of the holder body 52.

Here, the first main bodies 131U, 131V, 131W, and 131J and the second main bodies 231U, 231V, and the second main bodies 231U, 231V, and 31J constituting the bus bar main bodies 31U, 31V, 31W, and 31J of the bus bars 30U, 30V, and 30W for the respective phases. The curvature radii R1 to R8 of 231W and 231J and the radius R9 of the bus bar body 31N of the neutral point bus bar 30N are set so as to satisfy the expressions (1) to (6), respectively.

Thus, the gap between the bus bar bodies 31U to 31N in the radial direction is minimized. In particular, as shown in FIG. 6, the second main body 231U of the U-phase bus bar 30U and the second main body 231W of the W-phase bus bar 30W are displaced inward in the radial direction toward the tip. It is possible to prevent an extra gap from being formed between the two main bodies 231U and 231W and the bus bar main body 31N of the neutral point bus bar 30N.

The inner diameter E1 of the holder body 52 is set larger than the diameter E2 (see FIG. 1) of the outer peripheral wall portion 11c of the insulator 11 attached to the stator core 10. As a result, as shown in FIG. 1, the bus bar unit 50 is in a state where it is disposed radially outside the insulator 11 and is disposed at a position where it wraps in the axial direction with the insulator 11. In the cylindrical portion 2d of the stator housing 2 to which the stator core 10 is press-fitted and fixed, an enlarged diameter portion 92 that receives the bus bar unit 50 is formed by a step at a position corresponding to the bus bar unit 50.

The outer peripheral surface of the holder main body 52 is fitted into the enlarged diameter portion 92, and the bus bar unit 50 is positioned in the radial direction. In addition, the bus bar unit 50 is positioned in the axial direction in such a manner that the holder main body 52 is placed on the stepped surface 92 a of the enlarged diameter portion 92. Further, a positioning groove 56 is formed along the axial direction on the outer peripheral surface of the holder main body 52, while a convex portion (not shown) facing the positioning groove 56 is formed on the enlarged diameter portion 92 of the stator housing 2. Is formed. Thereby, the circumferential positioning of the bus bar unit 50 is performed.

Here, since the terminals 35U, 35V, 35W, 35J, and 35N extend from the holder main body 52 toward the radially inner side in a state where the bus bar unit 50 is disposed on the radially outer side than the insulator 11, these The terminals 35U, 35V, 35W, 35J, and 35N are positioned substantially above the teeth 64 in the axial direction. For this reason, the routing path | route of the terminal part of the coil 12 pulled out from each teeth part 64 can be simplified.
By the bus bar unit 50 configured in this way, the coils 12 of each phase are connected as follows.

FIG. 14 is a connection diagram of the coil 12.
That is, as shown in the figure, each phase terminal 35U, 35V, 35W of each phase bus bar 30U, 30V, 30W of bus bar unit 50, connection terminal 35J of connection bus bar 30J, and neutral point bus bar 30N are connected. By connecting a predetermined terminal portion of each phase coil 12 to each terminal 35N, each phase coil 12 is connected in a so-called star connection system. Moreover, when winding the coil 12 around each tooth part 64, what is called double winding which winds the two coils 12 to each tooth part 64 and connects the terminals of these two coils 12 is adopted. (See FIGS. 3 and 5).

Specifically, for example, the coils 12Ua and 12Ub of the U-phase coil 12 are connected in parallel. Moreover, the coils 12Ua and 12Ub and the coils 12Uc and 12Ud are connected in series. Further, the coils 12Ua, 12Ub, 12Uc, 12Ud and the coils 12Ue, 12Uf, 12Ug, 12Uh are connected in parallel. In this way, the coils 12 of each phase constitute a parallel circuit.
The V-phase coil 12 and the W-phase coil 12 are configured in the same manner as the U-phase coil 12. For this reason, description about the V-phase coil 12 and the W-phase coil 12 is omitted.

(bracket)
1 and 2, an outer flange portion 2e is formed in the opening 2a of the stator housing 2, and a bracket 7 is provided so as to be placed on the outer flange portion 2e.
The bracket 7 is formed in a substantially disc shape so as to close the opening 2 a of the stator housing 2. An insertion hole 71 through which the rotation shaft 6 is inserted is formed at the radial center of the bracket 7. A bearing 21 for rotatably supporting the rotary shaft 6 is provided on the inner surface side of the insertion hole 71 (the surface on the stator 3 side, the right surface in FIG. 1). On the other hand, on the outer surface side (left side in FIG. 1) of the insertion hole 71, a seal portion 72 is provided for ensuring the sealing performance between the insertion hole 71 and the rotary shaft 6.

Further, a plurality of (three in this embodiment) through holes 73 for fastening and fixing the bracket 7 and the stator housing 2 with bolts (not shown) or the like are provided at equal intervals in the circumferential direction on the outer peripheral portion of the bracket 7. Is formed.

Here, the outer flange portion 2e of the stator housing 2 is formed with a tongue piece portion 18 extending outward in the radial direction at a location corresponding to the through hole 73 of the bracket 7. A through hole 18 a corresponding to the through hole 73 of the bracket 7 is formed in the tongue piece 18.
In addition to the through hole 18a, the tongue piece 18 is formed with an attachment hole 18b for fixing the brushless motor 1 to the vehicle body of the electric motorcycle, and for positioning the stator housing 2 and the bracket 7 together. A hole 18c into which a positioning pin (not shown) is inserted is provided.

Further, in the outer flange portion 2e of the stator housing 2, a substantially rectangular grommet receiving portion 19 is elongated in the circumferential direction at a location corresponding to the power feeding portions 39U, 39V, 39W of the bus bar unit 50 in an axial plan view. Is formed. The grommet receiving portion 19 is for holding the grommet 54 attached to the power feeding portions 39U, 39V, 39W of the bus bar unit 50 in cooperation with the bracket 7. A grommet storage recess 74 that can receive the grommet 54 is formed on the outer periphery of the bracket 7.

The grommet 54 is for improving the sealing performance between the stator housing 2 and the bracket 7 and between the stator housing 2 and the bracket 7 and the power feeding portions 39U, 39V, and 39W of the bus bar unit 50. The grommet 54 is formed in a substantially rectangular parallelepiped shape so as to be elongated along the circumferential direction of the stator housing 2 by an elastic material such as rubber, in other words, so as to be elongated in the arrangement direction of the power feeding portions 39U, 39V, 39W. Is formed. And the insertion hole 54a which can penetrate these electric power feeding part 39U, 39V, 39W is formed in the position corresponding to electric power feeding part 39U, 39V, 39W.

Further, the grommet 54 is formed with a gasket retaining groove 55 a along the longitudinal direction on one side surface 54 b that contacts the grommet receiving portion 19 of the stator housing 2. In addition, on both ends in the longitudinal direction of the grommet 54, gasket circulation holes 55 b are formed along the axial direction of the stator housing 2.
Each gasket circulation hole 55b communicates with the gasket pool groove 55a. The gasket pool groove 55a and the gasket circulation hole 55b are places where the liquid gasket G applied when the brushless motor 1 is assembled is filled.

(Assembly of brushless motor)
Here, when assembling the brushless motor 1, the stator 3 is press-fitted into the cylindrical portion 2d of the stator housing 2, and the bus bar unit 50 is set with the grommet 54 mounted thereon, and the rotor 4 is set. The bracket 7 is assembled so as to close the opening 2 a of the stator housing 2. When the bracket 7 is assembled, a liquid gasket G is applied to improve the sealing performance between the bracket 7 and the stator housing 2.

That is, as shown in detail in FIG. 2, after the stator 3, the rotor 4, and the bus bar unit 50 are assembled to the stator housing 2 and before the bracket 7 is assembled, the outer flange portion 2 e of the stator housing 2. And a liquid gasket G is applied between the outer periphery of the bracket 7. Further, the liquid gasket G is applied to the other side surface 54c of the grommet 54 opposite to the grommet receiving portion 19.

Further, the liquid gasket G is injected into the gasket circulation hole 55 b formed in the grommet 54. Then, the liquid gasket G is filled into the gasket pool groove 55a through the gasket circulation hole 55b. For this reason, even when the liquid gasket G is applied after the bus bar unit 50 is assembled to the stator housing 2, the liquid gasket G is easily spread between the grommet receiving portion 19 and the grommet 54 of the stator housing 2. Can be made.
Thus, after applying the liquid gasket G along the outer flange portion 2e of the stator housing 2, the stator housing 2 and the bracket 7 are fastened and fixed by bolts (not shown), thereby completing the assembly of the brushless motor 1. .

(effect)
Therefore, according to the above-described embodiment, by setting the inner diameter E1 of the holder main body 52 of the bus bar unit 50 to be larger than the diameter E2 of the outer peripheral wall portion 11c of the insulator 11 attached to the stator core 10, the stator housing 2 Inside, the bus bar unit 50 and the insulator 11 can be arranged at a position where they are wrapped in the axial direction.
For this reason, the height H1 (see FIG. 1) from the stator core 10 to the bus bar unit 50 can be suppressed by this amount. As a result, the axial length of the brushless motor 1 can be shortened, and the brushless motor 1 can be downsized.

Further, since the terminals 35U, 35V, 35W, 35J, and 35N extend from the holder main body 52 toward the radially inner side in a state where the bus bar unit 50 is disposed on the radially outer side than the insulator 11, each of these terminals The terminals 35U, 35V, 35W, 35J, and 35N are positioned substantially above the teeth 64 in the axial direction. For this reason, the routing path | route of the terminal part of the coil 12 pulled out from each teeth part 64 can be simplified.

Furthermore, since the bus bar unit 50 is disposed on the radially outer side than the insulator 11, it is easy to secure a space in the upper axial direction of each tooth portion 64, and the heat dissipation effect of the heat generated in the coil 12 can be enhanced. . For this reason, the temperature rise of the brushless motor 1 can be suppressed, and the motor efficiency of the brushless motor 1 can be increased.
Since the heat generated from the stator core 10 is less likely to be transmitted to the bus bar unit 50, the temperature rise of the bus bar unit 50 can be more reliably suppressed. As a result, the motor efficiency of the brushless motor 1 can be further increased. Become.

Further, the bus bar bodies 31U, 31V, 31W, 31J of the bus bars for the phases 30U, 30V, 30W and the connection bus bar 30J are respectively connected to the first bodies 131U, 131V, 131W, 131J having different radii of curvature and the second bodies 231U. , 231V, 231W, and 231J. That is, the curvature radii R1 to R8 of the first main body 131U, 131V, 131W, 131J and the second main body 231U, 231V, 231W, 231J and the radius R9 of the bus bar main body 31N of the neutral point bus bar 30N are respectively expressed by equations. (1) to (6) are set to be satisfied.

Therefore, the gap between the bus bar bodies 31U to 31N in the radial direction can be minimized. In particular, there is an excess gap between the second main body 231U of the U-phase bus bar 30U and the second main body 231W of the W-phase bus bar 30W and the bus bar main body 31N of the neutral point bus bar 30N. Can be prevented. Therefore, the radial direction of the bus bar unit 50 can be reduced, and as a result, the brushless motor 1 can be reduced in size.

Here, each bus bar 30U, 30V, 30W is formed in the middle of the bus bar main body 31U, 31V, 31W, 31J in the extending direction of each phase bus bar 30U, 30V, 30W and the connection bus bar 30J. , 30J can be changed to reduce the diameter of the bus bar unit 50 in the radial direction. However, each phase bus bar 30U, 30V, 30W and connection bus bar 30J are formed by continuously changing the radius of curvature of each bus bar body 31U, 31V, 31W, 31J without forming a bent portion. Becomes easy, and the manufacturing cost can be reduced.

Further, in order to integrate each phase bus bar 30U, 30V, 30W including the connection bus bar 30J and the neutral point bus bar 30N, the holder main body 52 in which the respective groove portions 53U, 53V, 53W, 53J, 53N are formed. Is used. Then, by forming the retaining claws 57a and 57b on part of the opening edges of the groove portions 53U, 53V, 53W, 53J and 53N of the holder main body 52, the connection bus bars 30J from the holder main body 52 are included. It is possible to reliably prevent the phase bus bars 30U, 30V, 30W and the neutral point bus bar 30N from coming off. Thus, in order to integrate each phase bus bar 30U, 30V, 30W including the connection bus bar 30J and the neutral point bus bar 30N, it is not necessary to mold them with a resin mold body. No need for large-scale equipment. The facilities for manufacturing the bus bar unit 50 can be simplified as compared with the prior art, and the manufacturing cost of the bus bar unit 50 can be reduced.

Further, since the retaining claws 57a, 57b are formed to prevent the retaining, the phase bus bars 30U, 30V, 30W including the connecting bus bar 30J, the neutral point bus bar 30N, and the grooves 53U, 53V, It is not necessary to manage the dimensional tolerances of 53W, 53J, and 53N with high accuracy. For this reason, each bus- bar 30U, 30V, 30W, 30J, 30N and the holder main body 52 can be manufactured easily, and manufacturing cost can be reduced.
And the shape of each bus-bar main body 31U, 31V, 31W, 31J is made into the shape different from the shape of each groove part 53U, 53V, 53W, 53J, and the case where it hold | maintains with the elasticity of each bus-bar main body 31U, 31V, 31W, 31J The bus bar bodies 31U, 31V, 31W, 31J can be securely held.

Further, a die-cutting hole 58 (not shown) is formed on the other side in the axial direction where the retaining claws 57a and 57b of the holder main body 52 are formed. By using the punching hole 58, the undercut portions (not shown) of the retaining claws 57a and 57b can be easily formed. Thereby, the structure of a metal mold | die not shown can be simplified, As a result, the manufacturing cost of the holder main body 52 can be reduced.

Further, when the coils 12 are wound around the teeth portions 64, so-called double winding is employed in which the two coils 12 are wound around the respective tooth portions 64 and the terminals of the two coils 12 are connected to each other. . Thereby, since the coil 12 of each phase has comprised the parallel circuit, respectively, the total resistance of the coil 12 wound by each teeth part 64 can be suppressed, reducing the wire diameter of the coil 12. FIG. For this reason, while being able to make the coil 12 thinner, the winding work can be facilitated, and the dead space can be reduced as compared with the large-diameter coil, and the space factor can be improved. .

And when winding the coil 12 around each tooth part 64, the loop part 12a is formed in the coil 12 in the middle of winding around the tooth part 64 (between the 28th and 29th times in this embodiment), By cutting the loop portion 12a, a single coil 12 is continuously wound around the tooth portion 64, and double winding is performed.
For this reason, the time of winding work can be shortened compared with normal double winding. Moreover, the cost of the apparatus for winding the coil 12 can be reduced. That is, for example, in the case of performing double winding, there may be a need for equipment for winding two coils around the tooth portion 64 simultaneously using two nozzles. However, in the present embodiment, a single nozzle is used, and the single winding can be operated by simply operating this single nozzle. Therefore, the cost of the apparatus for winding the coil 12 can be reliably reduced.

In addition, a gasket retaining groove 55a is formed on one side surface 54b of the grommet 54 attached to the power feeding portions 39U, 39V, 39W of the bus bar unit 50, and gasket circulation holes 55b are formed on both ends in the longitudinal direction of the grommet 54. Yes. For this reason, even when the liquid gasket G is applied after the bus bar unit 50 is assembled to the stator housing 2, the liquid gasket G is easily spread between the grommet receiving portion 19 and the grommet 54 of the stator housing 2. Can be made. Therefore, the sealing performance between the stator housing 2 and the bracket 7 can be reliably improved.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.
For example, in the above-described embodiment, the case where the brushless motor 1 is used for an electric motorcycle has been described. However, the present invention is not limited to this, and the structure of the brushless motor 1 of this embodiment can be applied to various electric motors including the bus bar unit 50.
Moreover, in the above-mentioned embodiment, the case where the winding number of the coil 12 to each teeth part 64 was 28 times was demonstrated. However, the number of windings around the tooth portion 64 is not limited to 28, and the number of windings can be changed as appropriate in order to obtain desired motor characteristics.

Furthermore, in the above-described embodiment, the bus bar unit 50 is connected to one terminal portion of the coil 12 of each phase (U-phase bus bar 30U, V-phase bus bar 30V, W-phase bus bar 30W). And a neutral point bus bar 30N connected to the other terminal portion of the coil 12 of each phase, and the coil 12 of each phase is connected by a so-called star connection method by the neutral point bus bar 30N. Explained the case. However, the present invention is not limited to this, and the configuration of the present invention can be applied to a so-called delta connection method that does not have a neutral point. In this case, the bus bar unit 50 does not have the neutral point bus bar 30N.

And in the above-mentioned embodiment, the case where the grommet 54 was formed with elastic materials, such as rubber | gum, was demonstrated. However, the present invention is not limited to this, and any material that can ensure a sealing property between the stator housing 2 and the bracket 7 may be used. For example, the grommet 54 may be formed of a resin material instead of rubber.

In the above-described embodiment, the grommet 54 attached to the power feeding portions 39U, 39V, and 39W of the bus bar unit 50 has a gasket along the longitudinal direction on one side surface 54b that abuts the grommet receiving portion 19 of the stator housing 2. The case where the retaining groove 55a is formed to improve the sealing performance between the grommet receiving portion 19 and the grommet 54 of the stator housing 2 has been described. However, the present invention is not limited to this, and the grommet 54 may be formed with the following gasket pool groove 155a.

(Modification)
FIG. 15 is a plan view of a grommet 154 in a modification of the present embodiment. In FIG. 15, the same reference numerals are given to the same aspects as those in the above-described embodiment, and the description thereof is omitted.
As shown in the figure, gasket circulation holes 55 b are formed along the axial direction of the stator housing 2 at both ends of the grommet 54 in the longitudinal direction. Further, on both side ends in the longitudinal direction of the grommet 54, two gasket retaining grooves 155 that are substantially L-shaped in an axial plan view are formed on one side surface 54 b that contacts the grommet receiving portion 19 of the stator housing 2.

The gasket pool groove 155 will be described in detail. Each gasket pool groove 155 communicates with the gasket circulation hole 55b. The gasket pool groove 155 includes a first groove portion 155a that extends radially outward from the gasket circulation hole 55b along the extending direction of the power feeding portions 39U, 39V, and 39W, and the gasket housing hole 55b. And a second groove 155b extending outward along the circumferential direction. The first groove portion 155a and the second groove portion 155b are formed so as to communicate with each other and have a substantially L shape in an axial plan view. Thus, even when the gasket retaining groove 155 is formed in the grommet 54, the same effect as that of the above-described embodiment can be obtained.

According to the brushless motor described above, the insulator and the bus bar unit can be wrapped in the axial direction. For this reason, the height from the stator core to the bus bar unit can be suppressed correspondingly, and as a result, the axial length of the brushless motor can be shortened, and the brushless motor can be miniaturized.

DESCRIPTION OF SYMBOLS 1 Brushless motor 4 Rotor 10 Stator core 11 Insulator 12 Coil 12a Loop part 30J Connection bus bar (phase bus bar)
30N Neutral point bus bar 30U U phase bus bar (phase bus bar)
30V V-phase bus bar (phase bus bar)
30W W phase bus bar (phase bus bar)
31J, 31N, 31U, 31V, 31W Busbar body 35J Connection terminal (phase terminal)
35N Neutral point terminal 35U U-phase terminal (phase terminal)
35V V-phase terminal (phase terminal)
35W W phase terminal (phase terminal)
50 Bus bar unit 51 Bus bar holder 52 Holder body 53J, 53N, 53U, 53V, 53W Groove (groove)
54 Grommet 54b One side (the other plane)
55a Gasket Retaining Groove 55b Gasket Distribution Holes 57a, 57b Retaining Claw 64 Teeth (Teeth)
E1 Inner diameter E2 Diameter G Liquid gasket (liquid sealing material)
R1 to R9 radius of curvature

Claims (5)

1. A stator core;
   A rotor that is disposed radially inside the stator core and is rotatably supported with respect to the stator core;
   A brushless motor comprising a ring-shaped bus bar unit for supplying power to a plurality of phase coils wound around the stator core via an insulator,
   The bus bar unit is
   A plurality of curved phase bus bars provided for each phase and having phase terminals connected to one end of the coil;
   A ring-shaped bus bar holder made of an insulating member that holds the plurality of phase bus bars;
   The brushless motor which set the diameter of the internal peripheral surface of the said bus-bar holder larger than the diameter of the outer peripheral surface of the said insulator, and has arrange | positioned the said bus-bar unit radially outside the said insulator.
2. The plurality of phase bus bars are formed by curving the thickness direction of the band-shaped metal plate, and each phase bus bar is arranged side by side in the radial direction,
   2. The brushless motor according to claim 1, wherein at least one of the bus bars for each phase is formed so that the radius of curvature changes from the middle in the circumferential direction.
3. The bus bar holder has a holder body formed in a ring shape, and a plurality of grooves into which the plurality of phase bus bars can be inserted from one side in the axial direction are formed side by side in the holder body. ,
   The brushless motor according to claim 1, wherein a retaining claw for preventing the plurality of phase bus bars from coming off is formed on at least a part of the opening edge of each groove.
4. 4. The brushless motor according to claim 1, wherein two coils are wound around each tooth of the stator core so as to form a parallel circuit.
5. The bus bar unit includes a grommet,
   The grommet is
   A gasket circulation hole for injecting a liquid sealing material formed from one plane of the grommet,
   The brushless motor according to any one of claims 1 to 4, further comprising a gasket reservoir groove formed over the entire other plane of the grommet and communicating with the gasket circulation hole.

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