JP3306690B2 - Brushless motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor mainly used for a blower of a vehicle air conditioner.

[0002]

2. Description of the Related Art A brushless motor used in a conventional vehicle air conditioner is disclosed, for example, in Japanese Patent Application Laid-Open No. 4-42750. This brushless motor is
A jacket 16 extending upward from the storage case 14
A rotary shaft 34 rotatably held by a bearing 36 is fixed to an upper end of the rotary shaft 34. A yoke 28 formed in an umbrella shape is fixed to the upper end of the rotary shaft 34. On the peripheral surface, a plurality of permanent magnets 40 whose magnetic poles are oriented in the same direction in the circumferential direction are arranged to constitute the rotor 7.

An armature (stator) 5 is fixed to the sleeve 16 and extends radially from a central portion of the permanent magnet 4.
The stator core includes a stator core extending to a position opposite to the stator core 0 and an exciting coil 12 wound around the stator core.

Further, a printed circuit board 9 having an excitation circuit for supplying a current to the excitation coil 12 and generating a rotating magnetic field in the stator 5 is disposed in the storage case 14.

In the brushless motor having the above configuration,
The sirocco type fan 3 is fixed to the rotating shaft 34, and the rotor 7 is rotated by the rotating magnetic field generated in the stator 5, so that the sirocco type fan 3 can be rotated.

[0006]

However, in the conventional brushless motor, abnormal noise due to shaft run-out occurs due to bearing clearance between the bearing and the rotating shaft.
In addition, there is a problem that the bearing is deteriorated.

In order to prevent the shaft from being unraveled, a rotating shaft is radially urged by an elastic member such as a spring to prevent the shaft from unraveling (Japanese Utility Model Laid-Open No. 61-114960).
One in which the rotating shaft is radially urged by an elastic member and the rotation of the rotating shaft is absorbed by the elastic member
Japanese Patent Application Laid-Open No. 5-153755 discloses a method in which a convex portion of a side pressure spring inserted into a frame is elastically provided on a side pressure receiving plate on an upper portion of a rotor so that a shaft is pressed against a sign of a bearing. Gazette).

However, in these references, since the rotating shaft is urged in one direction by contacting the rotating shaft, there is a problem that the rotating resistance of the rotating shaft is large and the power loss is large. There was a problem that extra parts and configurations were required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a brushless motor having a simple structure and capable of urging a rotating shaft in a predetermined direction to prevent the rotating shaft from rotating.

[0010]

SUMMARY OF THE INVENTION Accordingly, the present invention provides
A rotor having a permanent magnet and fixed to a rotating shaft, a stator for generating a rotating magnetic field for the rotor, a control board for energizing an exciting coil wound on the stator, and the control board are housed therein. And a holding case made of a magnetic material member is provided at a position facing a permanent magnet attached to the rotor, and the holding plate fixes the stator to the housing case. It is characterized by being constituted by a core holder (claim 1).

Further, the ratio of a portion of the holding plate close to the permanent magnet may be increased on one side as compared with the other side, or a part of the holding plate may be made of a non-magnetic member. It may be formed (claim 3), and the holding plate may be inclined (claim 4).

[0012]

Therefore, according to the present invention, since the holding plate made of a magnetic member is provided at a position facing the permanent magnet attached to the rotor, the holding plate is attracted to the permanent magnet by magnetic force. Since the urging force acts on the rotor and the rotating shaft in the direction of the holding plate, it is possible to prevent the shaft from rotating. In addition, since the holding plate is constituted by the core holder for fixing the stator to the storage case, the above-described operation can be achieved with a simple structure.

The ratio of the portion of the holding plate close to the permanent magnet may be increased on one side as compared with the other side, or a part of the holding plate may be formed of a non-magnetic member. By inclining the holding plate, a difference occurs in the attraction force of the holding plate due to the magnetic force of the permanent magnet, and the rotating shaft can be urged to one side without contacting the rotating shaft. In addition, it is possible to prevent the shaft from rotating.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

A brushless motor 1 shown in FIG. 1 is used, for example, as a blower of a vehicle air conditioner. A sirocco-type fan 3 is fixed to an upper portion of a rotating shaft 2, and the position of the fan 3 is fixed. The rotor 4 is fixed near the lower part.

The rotor 4 has a yoke 42 composed of a boss portion 41 fixed to the rotary shaft 2 and a cylindrical portion 44 which extends in an umbrella shape from the boss portion 41 and has an outermost peripheral portion formed in a cylindrical shape.
And a plurality of permanent magnets 43 sequentially arranged on the inner peripheral surface of the cylindrical portion 44 so as to have the same polarity in the circumferential direction. The yoke 42 is formed of a magnetic member so that the magnetic flux leakage of the permanent magnet 43 is suppressed. An annular permanent magnet 8 is fixed to the lower end of the rotating shaft 2, and the Hall element 9 detects the magnetic pole position of the permanent magnet 8 to correspond to the magnetic pole position of the permanent magnet 43. Magnetic pole detection can be performed.

The armature (stator) 10 is, for example, a stator core 11 made of an iron core formed by stacking silicon steel plates in multiple stages.
And upper and lower insulating covers 12, 13 for insulating the stator core 11 and the exciting coil 16 wound around the stator core 11 and holding the stator core 11.
It is mounted on the fixed shaft 5 fixed to (7a, 7b) and urged downward by the fixed spring 20 to be fixed to the fixed shaft 5. The rotating shaft 2 is inserted into the fixed shaft 5 and is rotatably supported by a bearing 6 arranged on an inner peripheral portion of the fixed shaft 5.

An exciter circuit (not shown) for exciting the stator 10 is formed on the printed circuit board 15, and the position of the magnetic pole of the permanent magnet 8 fixed to the rotating shaft 2 is determined by, for example, the printed circuit board. A predetermined number of Hall elements 9 arranged on the reference numeral 15 detect the signals, and based on the detection signals, sequentially and alternately energize the exciting coils 16 of each phase of the stator 10 with a predetermined phase difference to generate a rotating magnetic field. .

In FIG. 1, reference numeral 17 denotes a power field effect transistor (FET) for turning on and off the supply of current to the exciting coil 16, and reference numeral 18 denotes a heat radiating plate.

The insulating cover 13 is formed as shown in FIG.
As shown in (a) and (b), a central hole 31 into which the fixed shaft 5 is inserted, a peripheral wall portion 32 composed of side surfaces arranged in a regular hexagon around the central hole 31, and A stator core storage portion 33 formed of a storage wall extending radially, and a stator core storage portion 3 at a predetermined position.
It has a fixed leg 34 formed to extend in an L-shape from 3. A mounting groove 36 is formed in the upper and lower portions of the fixing portion 35, which is a portion extending in the radial direction of the fixing leg 34, for fitting a cushioning material 60 described below. In the present embodiment, the fixing legs 34 are formed in three stator core storage portions 33 positioned alternately among the six stator core storage portions 33 extending from the six side surfaces. Number, stator core storage part 3 extended from this side
The number of 3 and the number of stator core storage portions 33 in which the fixed legs 34 are formed are not particularly limited.

Further, the stator core 11 is mounted on the insulating cover 13 to form the stator 10 and the exciting coil 1
6 is inserted around the fixed shaft 5 by winding. In addition, fixed legs 34 extending from the insulating cover 13 are formed.
A predetermined elastic member, for example, a cushioning material 60 made of natural rubber, synthetic rubber, synthetic resin, or the like is fitted into the mounting groove 36 formed in the fixing portion 35, and a core holder 50 described below and an upper case of the storage case 7 are inserted. At 7a, the cushioning material 60 is sandwiched and fixed.

As shown in FIG. 3, the core holder 50 as a holding plate according to the first embodiment of the present invention is formed in an annular shape by a magnetic member such as an iron plate, and a fixing portion 35 of the insulating cover 13 is provided. And a trough 52 having a hole 53 for fixing the core holder 50 to the storage case 7. In the core holder 50 according to the first embodiment shown in FIG. 4, the peak 51 protruding at a position facing the permanent magnet 43 is made as large as possible to increase the attraction force due to the magnetic force of the permanent magnet 43. Things. As a result, a large urging force acts on the rotating shaft 2 toward the storage case in the axial direction, so that it is possible to prevent the shaft of the rotating shaft 2 from rotating in the bearing clearance between the rotating shaft 2 and the bearing 6. .

A core holder 50 as a holding plate according to the second embodiment shown in FIG. 4 includes a semicircular member 50a formed of a magnetic member such as an iron plate and a non-magnetic member such as a synthetic resin. And a semi-circular member 50b formed by In addition, in the core holder 50 shown in FIG.
Although the peaks 51a and 51b are formed large, they may be large enough to fix the fixing portion 35. In this embodiment, the permanent magnet 43 is pulled toward the semi-circular member 50a formed of a magnetic member, and is not pulled toward the semi-arc member 50b formed of a non-magnetic member. As shown in FIG. 7, a predetermined force is applied to the rotating shaft 2 so that the rotating shaft 2 can be pressed against one side of the bearing 6, and the above-mentioned shaft flapping of the rotating shaft 2 is further reduced. It can be effectively prevented.

A third embodiment is shown in FIG. 5 as in the second embodiment, in which a side force is applied to the rotating shaft 2 to prevent the shaft from rotating. In the third embodiment, the core holder 50 as the holding plate is provided with a ridge 5 for fixing the fixing portion 35 of the insulating cover 13.
The size 1 is such that the peak 51a on one side is large and the peak 51b on the other side is small. As a result, the attraction force of the permanent magnet 43 causes a difference between one side and the other side, so that a side force can be generated on the rotating shaft 2 and the same as in the second embodiment. The effect can be achieved.

Also, in the fourth embodiment shown in FIG. 6, by forming the portion of the core holder 50 facing the permanent magnet 43 at an angle, the attraction force of the permanent magnet 43 is increased on one side. Since the other side can be weakened, a side force can be generated on the rotating shaft 2.

Further, a seal made of a non-magnetic material is put on a part of the surface of the core holder 50 made of a magnetic material as a holding plate, or the core holder 50 itself is formed of a non-magnetic material. By covering a part of the surface of the core holder 50 with a seal made of a magnetic member, the attraction force of the permanent magnet 43 of the rotor 2 may be changed to apply a side force to the rotating shaft 2. Things.

[0027]

As described above, according to the present invention, since the holding plate made of a magnetic material is provided at the portion of the rotor facing the permanent magnet, the rotor is attached to the rotating shaft by the attractive force of the permanent magnet. Because it can give power,
Shaking of the rotating shaft in the bearing clearance between the rotating shaft and the bearing can be prevented. Further, since the holding plate is constituted by the core holder for fixing the stator to the storage case, it is possible to prevent the shaft from being rounded with a simple structure.

Particularly, one side of the holding plate is formed of a magnetic material and the other side is formed of a non-magnetic material, the size of the crest of the holding plate is changed, or the holding plate is inclined. By doing so, the direction of the urging force applied to the rotating shaft can be changed so that the rotating shaft can be pressed against one side of the bearing, so that it is possible to more reliably prevent the shaft from rotating. In addition, since there is no member that comes into contact with the rotating shaft and it can be urged in one direction, power loss at the rotating shaft can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a brushless motor according to an embodiment of the present invention.

FIG. 2A is a perspective view of an insulating cover according to an embodiment of the present invention, and FIG. 2B is a plan view.

FIG. 3 is a plan view of a core holder as a holding plate according to the first embodiment of the present invention.

FIG. 4 is a plan view of a core holder as a holding plate according to a second embodiment of the present invention.

FIG. 5 is a plan view of a core holder as a holding plate according to a third embodiment of the present invention.

FIG. 6 is a plan view of a core holder as a holding plate according to a fourth embodiment of the present invention.

FIG. 7 is an explanatory diagram illustrating a relationship between a rotating shaft and a bearing when a lateral force is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brushless motor 2 Rotating shaft 3 Fan 4 Rotor 5 Fixed shaft 10 Stator 13 Insulation cover 50 Core holder 51 Mountain part 52 Valley part 60 Buffer material (elastic member)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-303344 (JP, A) JP-A 4-58065 (JP, U) JP-A-63-81659 (JP, U) (58) Investigation Field (Int.Cl. ⁷ , DB name) H02K 29/00 H02K 5/16 H02K 5/24 H02K 21/00

Claims (4)

(57) [Claims] 1. A rotor having a permanent magnet and fixed to a rotating shaft, a stator for generating a rotating magnetic field for the rotor, a control board for energizing an exciting coil wound around the stator, In a brushless motor having a storage case in which a control board is stored, a holding plate made of a magnetic material member is provided at a position facing a permanent magnet attached to the rotor, and the holding plate is provided with the stator. A brushless motor comprising a core holder fixed to a storage case. 2. The brushless motor according to claim 1, wherein a ratio of a portion of the holding plate close to the permanent magnet is larger on one side than on the other side. 3. The brushless motor according to claim 1, wherein a part of said holding plate is formed of a non-magnetic member. 4. The brushless motor according to claim 1, wherein said holding plate is inclined.