JPH11299149A - Brushless DC motor - Google Patents

Abstract

[PROBLEMS] To provide a brushless DC motor capable of securely fixing a cover to a magnet of a rotor, preventing a decrease in motor characteristics, reducing work processes, and manufacturing at low cost. To do. A rotor includes a shaft, a yoke attached to the shaft, a plurality of magnets attached to an outer periphery of the yoke along a circumferential direction thereof, and at least an outer peripheral surface of the magnet. A cover 30 that covers the axial end side,
A part of the magnets 2
3 is locked so that movement in the axial direction and the circumferential direction is restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless DC motor, and more particularly to a brushless DC motor provided with a cover for preventing a magnet attached to a rotor from peeling off.

[0002]

2. Description of the Related Art FIG. 14A shows a conventional brushless DC.
FIG. 2 is a perspective view showing a rotor 10 incorporated in the motor. The rotor 10 includes a shaft 11, a yoke 12 attached to the shaft 11, a magnet 13 adhered to the outer periphery of the yoke 12 with an adhesive or the like, and a cover 14 covered around the magnet 13. I have.

The cover 14 is for preventing the magnet 13 from peeling off from the yoke 12 due to chipping or cracking. As shown in FIG. 14B, such a cover 14 includes a cylindrical cover body 14a, side plates 14b and 14c for attaching the cover body 14a to the yoke 12, and a yoke 12 for connecting the side plates 14b and 14c. And a rivet 14d for attaching to the rivet 12. The cover body 14a includes side plates 14b, 14b.
Fixing in the axial direction can be performed by welding with c.

Further, since the magnet 13 is particularly susceptible to cracking and chipping at both ends in the axial direction, as shown in FIGS. 15 (a) and 15 (b), only the both ends of the cover body 15a have a bottomed cylindrical shape. In some cases, the rivets 15c are attached and fixed with rivets 15c.

As a method of fixing the cover bodies 15a, 15b to the magnet 13, the cover bodies 15a, 15b are bonded to the magnet 13 using an adhesive P as shown in FIG. As shown in FIG. 16 (b), a cylindrical portion 15d is provided on the bottom side of the cover main bodies 15a and 15b.
And press-fitting it to the shaft 11 or shrink-fitting it to the magnet 13 as shown in FIG. 16 (c). On the other hand, magnet 1 without cover
As a method of preventing the scattering of No. 3, there was a method of winding a wire of a glass tape or a non-magnetic material around the outer periphery of the magnet 13.

[0006]

The above-described conventional brushless DC motor has the following problems. That is, the method of using rivets for fixing the cover bodies 14a, 15a, 15b in the axial direction has a problem that the number of working steps is increased. In the method using an adhesive, the cover body 14a, 15a, 15b and the magnet 1
A space for applying an adhesive must be provided in advance between the magnet 13 and the magnet 3, so that the magnetic gap between the magnet 13 and the stator (not shown) becomes large, and the motor characteristics deteriorate. Is an unstable factor, and the reliability may be reduced. Further, the method using press-fitting and shrink fitting has a problem that dimensional control must be strictly performed.

Accordingly, the present invention provides a brushless DC motor which can securely fix a cover to a magnet of a rotor, can prevent motor characteristics from deteriorating, reduce the number of working steps, and can be manufactured at low cost. It is intended to be.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and achieve the object, an invention according to claim 1 is a brushless D-type motor in which a stator and a rotor are coaxially arranged.
In the C motor, the rotor includes a shaft, a yoke attached to the shaft, and a plurality of magnets attached to the outer periphery of the yoke along a circumferential direction of the yoke.
A cover for covering at least an axial end portion of the outer peripheral surface of the magnet, and the cover is partially engaged with the magnet so that movement of the magnet in the axial and circumferential directions is restricted between the magnets. Has been stopped.

According to a second aspect of the present invention, in the first aspect of the invention, the magnet is provided with a notch at a circumferential end thereof. Claim 3
In the invention described in (1), in the invention described in claim 1, the magnet has a circumferential end portion formed along a direction intersecting with the axial direction.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the cover includes a cylindrical cover body that covers both axial ends of the magnet. The portion is formed in a concave shape, and is fitted between the magnets.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the cover is provided with fins. As a result of taking the above-described means, the following operation occurs. That is, in the invention described in claim 1, since a part of the cover is locked by the magnet between the magnets so that the movement in the axial direction and the circumferential direction is restricted, the adhesive or special processing is performed. The cover can be securely fixed to the magnet without performing.

According to the second aspect of the present invention, since the notch is provided at the circumferential end of the magnet, the cover can be locked. According to the third aspect of the present invention, since the circumferential end of the magnet is formed along the direction intersecting with the axial direction, the cover can be locked.

[0013] According to the fourth aspect of the present invention, the fixing can be reliably performed without performing an adhesive or special processing. According to the fifth aspect of the present invention, since the fins are formed on the cover, wind is generated with the rotation of the rotor, and the temperature in the brushless DC motor is leveled. Therefore, the cooling efficiency of the motor itself can be increased.

[0014]

FIG. 1A is a perspective view showing a rotor 20 incorporated in a brushless DC motor according to a first embodiment of the present invention, and FIG.
FIG. 5 is a diagram showing the rotor 20 before being attached.

The rotor 20 includes a shaft 21, a yoke 22 attached to the shaft 21,
The magnet 23 includes a plurality of magnets 23 adhered to the outer periphery in the circumferential direction with an adhesive or the like, and a pair of covers 30, 30 covering the end portions of the magnets 23 in the axial direction. The cover 30 is for preventing the magnet 23 from being separated from the yoke 22 due to chipping or cracking.

A notch 23a is formed at the circumferential end of the magnet 23, and a gap 24 is formed between adjacent magnets 23. The cover 30 has a bottomed cylindrical cover main body 31, and a concave portion 33 is formed in an opening edge portion 32 of the cover main body 31, and is engaged with the gap portion 24. The movement of the cover main body 31 in the axial direction and the circumferential direction is restricted by the locking of the concave portion 33 in the gap portion 24.

The cover 30 is fixed to the magnet 23 of the rotor 20 as follows. That is,
As shown in FIG. 2A, the cover main body 31 is inserted from the axial end of the magnet 23 and pressed until the bottom 31a of the cover main body 31 contacts the axial end of the magnet 23. Thereby, the opening edge 32 of the cover body 31
Reaches the gap 24. Then, as shown in FIG. 2B, the opening edge 32 is swaged, and the opening edge 32 is locked in the gap 24. Thereby, the movement of the cover 30 in the axial direction and the circumferential direction with respect to the magnet 23 is restricted, and the cover 30 is securely fixed.

As described above, in the brushless DC motor according to the present embodiment, the magnet
0 can be reliably fixed, and it is not necessary to use a rivet or the like, so that the work process can be reduced. Further, since it is not necessary to use an adhesive, it is possible to prevent the motor characteristics from deteriorating and the occurrence of unstable elements of the adhesion. Furthermore, since strict dimensional control required for press-fitting, shrink-fitting, and the like is not required, it can be manufactured at low cost.

FIG. 3 is a view showing a rotor 40 according to a modification of the present embodiment. In the rotor 40 according to this modification,
A part of the bottom 31a of the cover body 31 is raised,
Fins 34 are formed. When the rotor 40 rotates, wind is generated by the fins 34, and the temperature in the brushless DC motor is leveled. Therefore, the cooling efficiency of the motor itself can be increased.

Incidentally, the method of locking the cover 30 to the magnet 23 is not limited to the above-described method, but is shown in FIGS.
Various modifications are possible as shown in FIG. FIG. 5A shows a brushless D according to a second embodiment of the present invention.
FIG. 6 is a perspective view illustrating the rotor 50 incorporated in the C motor, and FIG. 5B is a diagram illustrating the rotor 50 before the cover 30 is attached. In FIG. 5, the same reference numerals are given to the same functional portions as those in FIG.

The rotor 50 according to the present embodiment is different from the above-described rotor 20 in that a magnet 51 is used instead of the magnet 23. That is, the magnet 5
Notches 51a and 51b are formed at the circumferential end of the first magnet 51, and gaps 52 and 5 are provided between adjacent magnets 51.
3 are formed.

The cover 30 has a bottomed cylindrical cover body 31.
A concave portion 33 is formed in the opening edge portion 32 and is locked in the gap portions 52 and 53. Recess 3
Since the cover 3 is locked in the gaps 52 and 53, the movement of the cover main body 31 in the axial direction and the circumferential direction is restricted.

As described above, also in the rotor 50 according to the present embodiment, the same effects as those of the above-described rotor 20 can be obtained. FIG. 6A is a perspective view showing a rotor 60 incorporated in a brushless DC motor according to a third embodiment of the present invention, and FIG. 6B shows the rotor 60 before the cover 30 is attached. FIG. In FIG. 6, the same reference numerals are given to the same functional portions as in FIG.

The rotor 60 according to the present embodiment differs from the rotor 20 described above in that a magnet 61 is used instead of the magnet 23. That is, the magnet 6
Notch portions 61a and 61b are formed at the circumferential end portions of the magnet 1, respectively, and a gap portion 62 is formed between adjacent magnets 61.

The cover 30 has a bottomed cylindrical cover body 31.
A concave portion 33 is formed in the opening edge portion 32 and is locked in the gap portion 62. Since the concave portion 33 is locked in the gap portion 62, the cover body 31
Are restricted from moving in the axial and circumferential directions.

As described above, also in the rotor 60 according to the present embodiment, the same effects as those of the rotor 20 described above can be obtained. FIG. 7A is a perspective view showing a rotor 70 incorporated in a brushless DC motor according to a fourth embodiment of the present invention, and FIG. 7B shows the rotor 70 before the cover 30 is attached. FIG. In FIG. 7, the same reference numerals are given to the same functional portions as those in FIG.

The rotor 70 according to the present embodiment differs from the rotor 20 described above in that a magnet 71 is used instead of the magnet 23. That is, the magnet 7
Notch portions 71 a and 71 b are formed at the circumferential ends of the first magnet 1, respectively, and a gap 72 is formed between the adjacent magnets 71.

The cover 30 has a bottomed cylindrical cover body 31.
A concave portion 33 is formed in the opening edge portion 32 and is locked in the gap portion 72. Since the recess 33 is locked in the gap 72, the cover body 31
Are restricted from moving in the axial and circumferential directions.

As described above, also in the rotor 70 according to the present embodiment, the same effects as those of the rotor 20 described above can be obtained. FIG. 8A is a perspective view showing a rotor 80 incorporated in a brushless DC motor according to a fifth embodiment of the present invention, and FIG. 8B shows the rotor 80 before the cover 30 is attached. FIG. In FIG. 8, the same functional portions as those in FIG. 1 are denoted by the same reference numerals.

The rotor 80 according to the present embodiment differs from the rotor 20 described above in that a magnet 81 is used instead of the magnet 23. That is, the magnet 8
One circumferential end is formed linearly along a direction intersecting with the axial direction, and a gap 82 is formed between adjacent magnets 81.

The cover 30 has a bottomed cylindrical cover body 31.
The recess 35 is formed in a portion facing the gap 82 described above, and is locked in the gap 82.
Since the recess 35 is locked in the gap 72,
The movement of the cover body 31 in the axial direction and the circumferential direction is restricted.

As described above, also in the rotor 80 according to the present embodiment, the same effects as those of the rotor 20 described above can be obtained. FIG. 9A is a perspective view showing a rotor 90 incorporated in a brushless DC motor according to a sixth embodiment of the present invention, and FIG.
FIG. 9 is a view showing the rotor 90 before attachment. In FIG. 9, the same reference numerals are given to the same functional portions as those in FIG.

The rotor 90 includes a shaft 21, a yoke 22 attached to the shaft 21,
2 includes a plurality of magnets 23 adhered to the outer periphery along the circumferential direction with an adhesive or the like, and a cover 90 covering the outer periphery of the magnet 23. The cover 100 is for preventing the magnet 23 from being separated from the yoke 22 due to chipping or cracking.

Notches 23a are formed at circumferential ends of the magnets 23, and gaps 24 are formed between adjacent magnets 23. The cover 100 includes a cylindrical cover main body 101 and an axial intermediate portion 1 thereof.
02 has a recess 103 formed therein, which is engaged with the gap 24. Since the concave portion 103 is locked in the gap portion 24, the movement of the cover main body 101 in the axial direction and the circumferential direction is restricted.

The cover 100 is fixed to the magnet 23 of the rotor 90 as follows. That is, the cover main body 101 is inserted from the axial end side of the magnet 23 and pressed until the cover main body 101 covers the entire outer peripheral portion of the magnet 23. Then, the axial intermediate portion 102
To lock the recess 103 in the gap 24. Accordingly, the movement of the cover 100 in the axial direction and the circumferential direction with respect to the magnet 23 is restricted, and the cover 100 is securely fixed.

As described above, in the brushless DC motor according to this embodiment, the magnet 2 of the rotor 90
3, the cover 100 can be fixed securely, and it is not necessary to use a rivet or the like, so that the work process can be reduced. Further, since it is not necessary to use an adhesive, it is possible to prevent the motor characteristics from deteriorating and the occurrence of unstable elements of the adhesion. Furthermore, since strict dimensional control required for press-fitting, shrink-fitting, and the like is not required, it can be manufactured at low cost.

FIG. 10A shows a rotor 1 incorporated in a brushless DC motor according to a seventh embodiment of the present invention.
FIG. 10 is a perspective view showing the cover 10, and FIG.
FIG. 5 is a diagram showing the rotor 110 before being attached. FIG.
At 0, the same reference numerals are given to the same functional portions as those in FIGS.

The present embodiment is different from the above-described rotor 90 in that the rotor 110 is different from the rotor 90 in that a magnet 51 is used instead of the magnet 23. That is, the magnet 51
Notches 51a, 51b are formed at circumferential ends of the magnets 51, and gaps 52, 53 are provided between adjacent magnets 51.
Are formed.

The cover 100 has a cylindrical cover body 101.
The axially intermediate portion 102 has a recess 1
03 is formed and locked in the gaps 52 and 53.
Since the recess 103 is locked in the gaps 52 and 53, the movement of the cover main body 101 in the axial direction and the circumferential direction is restricted.

As described above, also in the rotor 110 according to the present embodiment, the same effects as those of the rotor 90 described above can be obtained. FIG. 11A is a perspective view showing a rotor 120 incorporated in a brushless DC motor according to an eighth embodiment of the present invention, and FIG. 11B shows the rotor 120 before the cover 100 is attached. FIG. Note that in FIG. 11, the same functional portions as those in FIGS. 6 and 9 are denoted by the same reference numerals.

The difference between the rotor 120 and the rotor 90 of the present embodiment is that a magnet 61 is used instead of the magnet 23. That is, the magnet 61
Notches 61a and 61b are formed at circumferential ends of the magnets 61, respectively.
2 are formed.

The cover 100 has a cylindrical cover body 101.
The axially intermediate portion 102 has a recess 1
03 is formed and locked in the gap 62. Since the concave portion 103 is locked in the gap portion 62, the movement of the cover main body 101 in the axial direction and the circumferential direction is restricted.

As described above, also in the rotor 120 according to the present embodiment, the same effects as those of the rotor 90 described above can be obtained. FIG. 12A is a perspective view showing a rotor 130 incorporated in a brushless DC motor according to a ninth embodiment of the present invention, and FIG. 9B shows the rotor 130 before the cover 100 is attached. FIG. In addition,
In FIG. 12, the same functional portions as those in FIGS. 7 and 9 are denoted by the same reference numerals.

The rotor 130 according to the present embodiment differs from the rotor 90 described above in that a magnet 71 is used instead of the magnet 23. That is, the notches 71a and 71b are provided at the circumferential ends of the magnet 71, respectively.
Are formed, and a gap 72 is formed between adjacent magnets 71.

The cover 100 has a cylindrical cover body 101.
The axially intermediate portion 102 has a recess 1
03 is formed and locked in the gap 62. The movement of the cover body 101 in the axial direction and the circumferential direction is restricted by the locking of the concave portion 103 in the gap portion 72.

As described above, also in the rotor 130 according to the present embodiment, the same effects as those of the rotor 90 described above can be obtained. FIG. 13A is a perspective view showing a rotor 140 incorporated in a brushless DC motor according to a tenth embodiment of the present invention, and FIG. 13B shows the rotor 140 before the cover 100 is attached. FIG. Note that, in FIG. 13, the same functional portions as those in FIGS. 8 and 9 are denoted by the same reference numerals.

The rotor 140 of the present embodiment differs from the rotor 90 described above in that a magnet 81 is used instead of the magnet 23. That is, the magnet 81
Are formed linearly along a direction intersecting the axial direction, and a gap 82 is formed between adjacent magnets 81.

The cover 100 has a cylindrical cover body 101.
A recess 104 is formed in a portion facing the above-mentioned gap 82, and is locked in the gap 82. Since the concave portion 104 is locked in the gap portion 82, the movement of the cover main body 101 in the axial direction and the circumferential direction is restricted.

As described above, the rotor 140 according to the present embodiment can also obtain the same effects as those of the rotor 90 described above. It should be noted that the present invention is not limited to the embodiments, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.

[0050]

According to the present invention, since a part of the cover is locked by the magnet between the magnets so that the movement in the axial direction and the circumferential direction is restricted, an adhesive or special processing is performed. The cover can be securely fixed to the magnet without any trouble. In addition, it is possible to prevent the motor characteristics from deteriorating, to reduce the number of working steps, and to manufacture the motor at low cost.

[Brief description of the drawings]

FIG. 1 shows a brushless D according to a first embodiment of the present invention.
FIG. 3 is a perspective view showing a rotor incorporated in the C motor.

FIG. 2 is a vertical sectional view of a main part showing a method of manufacturing the rotor.

FIG. 3 is a perspective view showing a modification of the rotor.

FIG. 4 is a vertical sectional view of a main part showing another modification of the rotor.

FIG. 5 shows a brushless D according to a second embodiment of the present invention.
FIG. 3 is a perspective view showing a rotor incorporated in the C motor.

FIG. 6 shows a brushless D according to a third embodiment of the present invention.
FIG. 3 is a perspective view showing a rotor incorporated in the C motor.

FIG. 7 shows a brushless D according to a fourth embodiment of the present invention.
FIG. 3 is a perspective view showing a rotor incorporated in the C motor.

FIG. 8 shows a brushless D according to a fifth embodiment of the present invention.
FIG. 3 is a perspective view showing a rotor incorporated in the C motor.

FIG. 9 shows a brushless D according to a sixth embodiment of the present invention.
FIG. 3 is a perspective view showing a rotor incorporated in the C motor.

FIG. 10 is a perspective view showing a rotor incorporated in a brushless DC motor according to a seventh embodiment of the present invention.

FIG. 11 is a perspective view showing a rotor incorporated in a brushless DC motor according to an eighth embodiment of the present invention.

FIG. 12 is a perspective view showing a rotor incorporated in a brushless DC motor according to a ninth embodiment of the present invention.

FIG. 13 is a perspective view showing a rotor incorporated in a brushless DC motor according to a tenth embodiment of the present invention.

FIG. 14 is a perspective view showing an example of a rotor incorporated in a conventional brushless DC motor.

FIG. 15 is a perspective view showing another example of a rotor incorporated in a conventional brushless DC motor.

FIG. 16 is a longitudinal sectional view of an essential part for explaining a method of fixing a cover in a rotor incorporated in a conventional brushless DC motor.

[Description of References] 20, 60, 70, 80, 90: rotor 21: shaft 22: yoke 23, 61, 71, 81, 91: magnet 23a: cutout portion 24, 52, 53, 62, 72, 82, 92 ... gap 30, 100 ... cover 31, 101 ... cover body 32 ... opening edge 33, 35, 102 ... recess 34 ... fin

Claims (5)

[Claims] 1. A brushless DC motor in which a stator and a rotor are coaxially arranged with each other, wherein the rotor is attached to a shaft, a yoke attached to the shaft, and an outer periphery of the yoke along a circumferential direction thereof. A plurality of magnets, and a cover that covers at least an axial end portion of the outer peripheral surface of the magnet, and the cover has a part that is axially and circumferentially moved by the magnet between the magnets. Brushless D characterized by being locked so as to be regulated
C motor. 2. The brushless DC motor according to claim 1, wherein the magnet has a notch at a circumferential end thereof. 3. The brushless DC motor according to claim 1, wherein the magnet has a circumferential end formed along a direction intersecting the axial direction. 4. The cover includes a cylindrical cover main body that covers both ends of the magnet in the axial direction, and a part of the cover main body is formed in a concave shape, and is fitted between the magnets. Claim 1 characterized by the following:
2. The brushless DC motor according to 1. 5. The brushless DC motor according to claim 1, wherein a fin is formed on the cover.