JPH05153761A - Brushless motor - Google Patents

Abstract

PURPOSE:To provide a brushless motor which saves, for the purpose of cost- down, the number of manufacturing man-hours, cost of metal dies and to the number of parts by integrally forming a back yoke of stator and a bearing with a sintered alloy of iron and to realize prevention of rust on the stator and reduction of vibration by impregnating the stator with oil. CONSTITUTION:A brushless motor comprises a stator 10 having a back yoke 10c and a bearing 10d and a rotor 20 having a permanent magnet 24 is rotatably supported by the bearing in opposition to the stator and integrally forms the back yoke of stator and the bearing with a sintered alloy of iron.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor in which a rotor having a permanent magnet rotates facing a stator.

[0002]

2. Description of the Related Art Conventionally, a brushless motor comprises a stator 50 and a rotor 60, as shown in the sectional view of FIG. The stator 50 includes a housing 52 having a bearing 51, a laminated iron core 53 arranged on the outer periphery of the housing 52, and a winding 54 wound around a slot (not shown) of the iron core 53. 55 is an insulating plate that insulates the winding 54 from the iron core 53, 56 is a thrust receiver, and 57 is a mounting plate of the housing 52. The rotor 60 includes a rotating shaft 61 rotatably supported by the bearing 51 of the stator 50, a boss 62 fixed to one end of the rotating shaft 61 by adhesion, press fitting, or the like, and by caulking the boss 62 or the like. Fixed cup-shaped rotor yoke 63
And attached to this rotor yoke 63, the stator
50 and a permanent magnet 64 disposed so as to face each other.

Such a brushless motor has a rotor 60
Is detected, a current corresponding to that position is passed through the winding 54 of the stator 50, and a driving force is applied to the rotor 60 by electromagnetic action with the permanent magnet 64 of the rotor 60.

However, in the conventional brushless motor, since the iron core 53 of the stator 50 has a complicated shape including a slot and it is necessary to reduce the iron loss, a plurality of thin silicon steel plates are punched out by a die, Since it is necessary to stack the sheets and crimp them with a rivet or directly crimp to the housing 52, there is a drawback that the number of manufacturing steps and the die cost increase. Moreover, the bearing 51 and the housing 52 incorporating the bearing 51
However, there is a drawback that the number of parts increases.

[0005]

SUMMARY OF THE INVENTION The brushless motor of the present invention has been made in order to solve the above-mentioned conventional drawbacks, in which the back yoke of the stator and the bearing are integrally made of a ferrous sintered alloy. By forming it, manufacturing man-hours, die cost and the number of parts can be reduced, cost can be reduced, and by impregnating the stator made of iron-based sintered alloy with oil, the rust prevention of the stator and the damper action can be achieved. The challenge is to reduce vibration.

[0006]

A brushless motor according to the present invention comprises a stator having a back yoke and a bearing, and a rotor having a permanent magnet rotatably supported by the bearing so as to face the stator. The back yoke and the bearing of the stator are integrally formed of a ferrous sintered alloy.

[0007]

In the brushless motor of the present invention, the back yoke of the stator and the bearing are integrally formed of an iron-based sintered alloy in this manner, thereby reducing manufacturing man-hours, die cost and the number of parts. By impregnating the stator made of sintered alloy with oil, it is possible to prevent the stator from rusting and to have a damper action against vibration.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A brushless motor according to a first embodiment of the present invention will be described below with reference to FIGS. 1 to 4 and a second embodiment with reference to FIG.

The first embodiment of the brushless motor of the present invention is, as shown in the sectional view of FIG. 1, a stator 10 and a rotor 20.
It consists of and. As shown in the front view of FIG. 2 and the sectional view of FIG. 3, the main part of the stator 10 is provided with a slot 10a, teeth 10b, and a back yoke 10c, and a bearing 10d is provided at the center of the back yoke 10c. Are provided, and the teeth 10b, the back yoke 10c, and the bearing 10d are integrally formed of an iron-based sintered alloy. Returning to the cross-sectional view of FIG. A winding 11 is wound around the slot 10 a of the stator 10. 12 is winding 11 from the teeth 10b of the stator 10
Is an insulating plate that insulates the
Is a mounting plate.

The rotor 20 has a rotating shaft 21 rotatably supported by a bearing 10d of the stator 10, a boss 22 fixed to one end of the rotating shaft 21 by adhesion, press fitting, etc., and the boss 22.
Cup-shaped rotor yoke fixed by crimping
23 and a permanent magnet 24 attached to the rotor yoke 23 and arranged so as to face the stator 10.

Such a brushless motor has a rotor 20
Position is detected, a current corresponding to the position is applied to the winding 11 of the stator 10, and a driving force is applied to the rotor 20 by electromagnetic action with the permanent magnet 24 of the rotor 20.

FIG. 4 is a partially enlarged sectional view of FIG. Since the stator 10 is formed of a ferrous sintered alloy, it has a large number of pores 10e. Therefore, the conventional laminated iron core 53
It is possible to reduce iron loss as well as. Incidentally, 10f is silicon, and this silicon 10f also has an effect of reducing iron loss.

A second embodiment of the brushless motor according to the present invention has a stator 10 and a rotor 20 as shown in the sectional view of FIG.
It consists of and. The stator 10 includes a back yoke 10c,
A bearing 10d is provided at the center of the back yoke 10c, and the back yoke 10c and the bearing 10d are integrally formed of a ferrous sintered alloy. Back yoke 10c of the stator 10
A winding 11 is wound around and attached to the. An insulating plate 12 for insulating the winding 11 from the back yoke 10c of the stator 10 described in the first embodiment is arranged, but is not shown. 13
Is a thrust bearing, and 15 is another bearing made of, for example, a copper-based sintered alloy, which is paired with the bearing 10d integrally formed of the iron-based sintered alloy of the stator 10.

The rotor 20 has a rotating shaft 21 rotatably supported by the bearings 10d and 15 of the stator 10, a boss 22 fixed to one end of the rotating shaft 21 by adhesion, press fitting, etc., and the boss 22. It comprises a cup-shaped rotor yoke 23 fixed by crimping or the like, and a disk-shaped permanent magnet 24 attached to the rotor yoke 23 and arranged so as to face the winding 11 of the stator 10. The boss 22 in the second embodiment also functions as a motor pulley.

Such a brushless motor has a rotor 20
Position is detected, a current corresponding to the position is applied to the winding 11 of the stator 10, and a driving force is applied to the rotor 20 by electromagnetic action with the permanent magnet 24 of the rotor 20.

As described above, according to the first and second embodiments of the brushless motor of the present invention, the back yoke 10c and the bearing 10d of the stator 10 are integrally formed of an iron-based sintered alloy, thereby reducing the number of manufacturing steps. It is possible to reduce the die cost and the number of parts to reduce the cost. Moreover, by impregnating the stator 10 made of iron-based sintered alloy with oil,
It is also possible to prevent rust of 10 and reduce vibration due to the damper action.

[0017]

As described above, the brushless motor of the present invention includes a stator having a back yoke and a bearing,
A rotor having a permanent magnet that is rotatably supported by the bearing so as to face the stator, and the back yoke and the bearing of the stator are integrally formed of an iron-based sintered alloy. Reduce costs and the number of parts to reduce costs. Moreover, by impregnating the stator made of a ferrous sintered alloy with oil, it is possible to prevent rusting of the stator and reduce vibration due to the damper action.

[Brief description of drawings]

FIG. 1 is a sectional view of a brushless motor according to a first embodiment of the invention.

FIG. 2 is a front view of the essential parts of the stator of the first embodiment of the brushless motor of the present invention.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a partially enlarged sectional view of FIG.

FIG. 5 is a sectional view of a second embodiment of the brushless motor of the present invention.

FIG. 6 is a sectional view of a conventional brushless motor.

[Explanation of symbols]

 10 Stator 10a Slot 10b Teeth 10c Back yoke 10d Bearing 10e Porous 10f Silicon 11 Winding 12 Insulation plate 13 Thrust bearing 14 Mounting plate 15 Another bearing 20 Rotor 21 Rotating shaft 22 Boss 23 Rotor yoke 24 Permanent magnet

Claims (1)

[Claims] 1. A brushless motor comprising: a stator having a back yoke and a bearing; and a rotor having a permanent magnet rotatably supported by the bearing so as to face the stator. A brushless motor characterized by being integrally formed of an iron-based sintered alloy.