JPH099597A - Brushless electric motor - Google Patents

Abstract

PURPOSE: To provide a brushless electric motor which generates little undesirable vibration and little noise due to resonance by interposing an elastomer between the flange of a bracket and a stator to fix the bracket to the stator. CONSTITUTION: In a brushless electric motor 14, a rotor 6 is inserted into the central part of a stator 5 which is integrally molded and solidified with a stator iron core 1 on which a winding 3 is wound through an insulating layer 2 by using a thermohardening resin 4 having an electric insulation property. A bracket 8 is fixed by fitting vibration proof rubber 12 and the flange part 13 of the bracket 8 into the recessed part of the axial end surface 10 of the stator 5 so as to hold the bearing part 7 of the rotor 6. Accordingly, since vibrations due to switching generated by driving the electric motor 14 are cut off by elasticity of the vibration proof rubber 12, the vibrations are prevented from being transmitted to the bracket 8. As a result, even when the number of revolutions of a blast fan is frequently controlled, the undesirable vibrations and noise due to the resonance of the bracket 8 caused by vibrations generated by switching can be prevented from being generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless electric motor in which a stator core and a winding of a small electric motor used as a blower fan driving source for a room air conditioner or a water heater are integrally molded.

[0002]

2. Description of the Related Art In recent years, the number of revolutions of a blower fan has been frequently controlled in terms of blowing efficiency or combustion efficiency.
The vibration frequency range generated by the switching of the brushless motor becomes wide, and the generation of unpleasant vibration and noise due to resonance tends to increase, and the demand for a brushless motor with low vibration and low noise is increasing. .

A conventional brushless motor of this type is shown in FIG.
Will be described with reference to. As shown in the figure, an annular stator core 51 having a plurality of slots is wound with a winding 53 via an insulating layer 52, and the stator core 51 is integrated with an electrically insulating thermosetting resin 54. After the rotor 56 is inserted into the central portion of the stator 55 that is molded and solidified into
A bracket 58 formed by drawing a sheet metal is fixed to the axial end surface 60 of the stator 55 by a through bolt or a rivet 59 so as to hold the bearing portion 57 of FIG.

[0004]

According to such a conventional brushless motor, since the frequency range of vibration generated by switching is high, the bracket 5 made of metal is used.
The resonance of No. 8 causes a problem that unpleasant vibration and noise are generated. Further, if it is attempted to increase the plate thickness of the metal plate in order to increase the rigidity of the bracket 58, there is a problem that the drawing process cannot be performed. Further, when the bracket is formed by casting or shaving, a high processing precision is required, which causes a problem of high cost.
Further, when the bracket is made of resin, there is a problem that the bearing causes creep or fretting.

The present invention solves the above-mentioned problems. Even if the rotation speed control of the blower fan is frequently performed, an unpleasant vibration and noise due to the resonance of the bracket caused by the vibration generated by the switching are less generated. The purpose is to provide an electric motor.

[0006]

In order to achieve the above-mentioned object, the first means of the vibration isolator for a fan motor according to the present invention is to provide an annular stator core having a plurality of slots and to the stator core. A winding formed through an insulating layer, a stator formed by integrally molding and solidifying the winding and the stator core with a thermosetting resin having electric insulation, and a central portion of the stator. An internal rotor and a bracket having a flange portion that holds a bearing portion that supports the rotor are provided, and the bracket is attached to the stator by interposing an elastomer between the flange portion of the bracket and the stator. It has a fixed configuration.

The second means is such that the flange portion of the bracket and the stator are fixed by an adhesive material and then fixed by screws or rivets.

Further, the third means is constituted by vulcanizing and adhering an elastomer to the outside of the bearing holding portion of the bracket.

The fourth means has a structure in which a cushioning material is coated on the outside of the bearing holding portion of the bracket.

The fifth means is constructed such that the outside of the bearing holding portion of the bracket is insert-molded with synthetic resin.

The sixth means is constituted by vulcanizing and adhering an elastomer having a constraining plate on the outer peripheral portion to the outside of the bearing holding portion of the bracket.

[0012]

According to the present invention, by virtue of the construction of the first means described above, the elasticity of the elastomer prevents the vibration generated by the switching from the stator from being transmitted to the bracket.

Further, according to the structure of the second means, the transmission of the vibration generated by the stator due to the switching to the bracket is blocked by the viscosity of the adhesive material.

Further, according to the structure of the third means, the elastomer vulcanized and adhered to the outer peripheral portion of the bearing holding portion of the bracket expands and contracts in thickness in accordance with the vibration caused by switching, and absorbs vibration energy. It will be.

Also in the structure of the fourth means, the cushioning material coated on the outer side of the bearing holding portion of the bracket expands and contracts according to the vibration caused by switching, thereby absorbing the vibration energy.

Further, according to the constitution of the fifth means, the synthetic resin molded outside the bearing holding portion of the bracket prevents resonance and prevents resonance sound from propagating in the air.

Further, according to the structure of the sixth means, the vibration energy due to switching is consumed due to the gap between the layers of the elastomer fixed at the two interfaces of the constraining plate and the bracket.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. As shown in the figure, an annular stator core 1 having a plurality of slots and a stator core 1 in which a winding wire 3 is wound via an insulating layer 2 are integrally formed with a thermosetting resin 4 having an electrically insulating property. After inserting the rotor 6 into the central portion of the stator 5 that has been molded and solidified into a bracket, a bracket 8 formed by drawing a metal plate is held so that the bearing portion 7 of the rotor 6 is held. A sheet-shaped anti-vibration rubber 12 is interposed on the end face 10 in the direction, and the anti-vibration rubber 12 and the flange portion 13 of the bracket 8 are fitted in the recess 11 of the end face 10 in the axial direction of the stator 5 to form a through bolt or rivet 9. And the brushless electric motor 14 is fixed.

In the above structure, the vibration caused by switching when the brushless motor 14 is driven is generated by the elasticity of the vibration-proof rubber 12 interposed between the axial end surface 10 of the stator 5 and the flange portion 13 of the bracket 8. Since it is cut off, vibration is prevented from being transmitted to the bracket 8.

As described above, according to the first brushless electric motor of the present invention, since the vibration proof rubber 12 prevents the vibration generated by the switching from being transmitted to the bracket 8, the rotation speed of the blower fan is controlled. Even if it is performed frequently, it is possible to prevent unpleasant vibration and noise due to the resonance of the bracket 8 caused by the vibration generated by switching.

In the first embodiment of the present invention, the antivibration rubber is used as the elastomer, but a thermoplastic polyurethane elastomer having a rich rubber elasticity may be used.
The effect is the same. Further, when a low-foamed elastomer is adopted, the amplitude at resonance is reduced due to internal viscosity, and the surging phenomenon is eliminated due to internal friction, so that it is possible to further reduce vibration and noise.

Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those of the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.
As shown in the figure, 15 is a double-sided tape which is a kind of adhesive material, and has a structure in which the flange portion 13 of the bracket 8 and the axial end surface 10 of the stator 5 are adhered, and the other structures are the first.
The configuration is the same as that of the above embodiment.

In the above-described structure, the vibration caused by the switching of the brushless motor 14 driven by the brushless motor 14 is blocked by the viscosity of the adhesive material 15 interposed between the axial end surface 10 of the stator 5 and the flange portion 13 of the bracket 8. Because
Vibration is prevented from being transmitted to the bracket 8.

As described above, according to the second brushless motor of the present invention, the adhesive material 15 prevents the vibration generated by the switching from being transmitted to the bracket 8, so that the rotation speed of the blower fan is frequently controlled. Even in this case, it is possible to prevent unpleasant vibration and noise due to the resonance of the bracket due to the vibration generated by switching.

In the second embodiment of the present invention, an adhesive material is used, but an elastic adhesive may be used.
The effect is the same.

Next, a third embodiment of the present invention will be described with reference to FIG. The same parts as those of the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.
As shown in the drawing, the bracket 16 has a structure in which a vibration-proof rubber 18 is vulcanized and adhered to the outside of the bearing holding portion 17, and the other structures are the same as those of the first embodiment.

In the above-mentioned structure, the vibration caused by switching the brushless motor 14 driven and generated by the switching energy generated by the vibration deformation of the vibration-proof rubber 18 vulcanized and adhered to the outside of the bearing holding portion 17 of the bracket 16 is converted into thermal energy. It is converted into energy to damp vibrations.

As described above, according to the third brushless electric motor of the present invention, due to the viscosity of the vibration-proof rubber 18 vulcanized and bonded to the outside of the bearing holding portion 17 of the bracket 16, the vibration-proof rubber 18 is provided.
The vibration generated by the switching is converted into heat by the expansion and contraction deformation and the thickness deformation, so that the uncomfortable vibration and noise due to the resonance of the bracket 16 can be prevented.

In the third embodiment of the present invention, a vibration-proof rubber is used as the elastomer, but a thermoplastic polyurethane elastomer having a rich rubber elasticity may be used.
The effect is the same. Further, when a low-foamed elastomer is adopted, the amplitude at resonance is reduced due to internal viscosity, and the surging phenomenon is eliminated due to internal friction, so that it is possible to further reduce vibration and noise.

Next, a fourth embodiment of the present invention will be described with reference to FIG. The same parts as those of the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.
As shown in the drawing, the bracket 19 is coated with a rubber-like paint 21 which is a kind of cushioning material on the outside of the bearing holding portion 20, and the other structure is the same as that of the first embodiment.

In the above structure, the vibration caused by switching by driving the brushless electric motor 14 is converted into thermal energy by the elastic deformation of the rubber-like paint 21 coated on the outside of the bearing holding portion 20 of the bracket 19. It is converted to damp the vibration.

As described above, according to the fourth brushless electric motor of the present invention, the vibration generated by switching is converted into heat by the viscosity of the rubber-like paint 21 coated on the outside of the bearing holding portion 20 of the bracket 19. Therefore, it is possible to prevent unpleasant vibration and noise due to the resonance of the bracket 19.

In the fourth embodiment of the present invention, the rubber-like paint is used as the cushioning material, but a vinyl tape having a high elasticity may be attached, and the function and effect are the same.

Next, a fifth embodiment of the present invention will be described with reference to FIG. The same parts as those of the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.
As shown in the figure, the bracket 22 is insert-molded with a polyamide resin 24 on the outside of the bearing holding portion 23,
The other structure is the same as that of the first embodiment.

In the above structure, the rigidity of the bracket 22 is increased by the polyamide resin 24 formed on the outside of the bearing holding portion 23 of the bracket 22, and the brushless motor 14 is driven, and the bracket is generated by the high frequency vibration caused by the switching. The resonance of 22 is suppressed.

As described above, according to the fifth brushless electric motor of the present invention, the bracket 22 is made of the polyamide resin 24 molded on the outside of the bearing holding portion 23 of the bracket 22.
Since the rigidity of the bracket 22 is increased, the resonance of the bracket 22 due to the high frequency vibration generated by the switching is suppressed, and the generation of unpleasant vibration and noise can be prevented.

In the fifth embodiment of the present invention, a polyamide resin is used as the synthetic resin to increase the rigidity of the bracket. However, if an elastic ethylene vinyl acetate resin is used, the vibration due to switching will be ethylene acetate. Due to the expansion and contraction of the vinyl resin, the vibration energy is converted into heat energy to damp the vibration, and in the same manner, the uncomfortable vibration and noise due to the resonance of the bracket 22 can be prevented.

Next, a sixth embodiment of the present invention will be described with reference to FIG. The same parts as those of the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.
As shown in the drawing, the bracket 25 has a structure in which a synthetic rubber 27 having an aluminum foil 28, which is a kind of a constraining plate, adhered to the outer peripheral portion of the bearing holding portion 26 by vulcanization.
The other structure is the same as that of the first embodiment.

In the above structure, the vibration generated by switching the brushless motor 14 when driven causes the vibration due to the shear deformation of the outside of the bearing holding portion 26 of the bracket 25 and the synthetic rubber 27 restrained by the aluminum foil 28. Energy is converted to thermal energy to damp vibrations.

As described above, according to the sixth brushless electric motor of the present invention, the inner peripheral side is outside the bearing holding portion 26 of the bracket 25, and the outer peripheral side is due to the viscosity of the synthetic rubber 27 vulcanized and bonded to the aluminum foil 28. Due to the shear strain, the vibration generated by switching is converted into heat, so the bracket 2
It is possible to prevent unpleasant vibration and noise due to the resonance of No. 5.

In the sixth embodiment of the present invention, the aluminum foil is used as the restraint plate, but any action can be used as long as it restrains the expansion and contraction of the elastomer, and the action and effect are the same.

[0042]

As is apparent from the above description of the embodiments, according to the present invention, an elastomer is interposed between the bracket and the axial end surface of the stator to fix the same.
Since the elastomer prevents the vibration generated by switching from being transmitted to the bracket, it is possible to realize a brushless electric motor excellent in low noise and low vibration without increasing the plate thickness of the bracket.

Even if the bracket and the axial end surface of the stator are fixed with an adhesive material and then fixed with screws or rivets, due to the viscosity of the adhesive material, the vibration generated by the switching can be transmitted to the bracket. Since it is cut off, it is possible to realize an excellent brushless electric motor with low noise and low vibration without increasing the thickness of the bracket plate.

Further, by vulcanizing and adhering the elastomer to the outside of the bearing holding portion of the bracket, it is possible to obtain a bracket having a vibration damping property of converting vibration into heat by viscousity of the elastomer, and it is uncomfortable due to resonance of the bracket. It is possible to realize a brushless electric motor that suppresses the generation of various vibrations and noises.

Even if the cushioning material is coated on the outside of the bearing holding portion of the bracket, the viscosity of the cushioning material causes
A bracket having vibration damping performance for converting vibration into heat can be provided, and a brushless electric motor that suppresses unpleasant vibration and noise due to bracket resonance can be realized.

Further, since the rigidity of the bracket is increased by insert-molding the outside of the bearing holding portion of the bracket with synthetic resin, it is possible to realize a brushless electric motor in which resonance due to high frequency vibration is suppressed.

Further, by vulcanizing and adhering an elastomer having a constraining plate on the outer peripheral surface to the outside of the bearing holding portion of the bracket, a bracket having a vibration damping property of converting vibration into heat by shear deformation of the elastomer is obtained. Therefore, it is possible to realize a brushless electric motor that suppresses unpleasant vibration and noise due to the resonance of the bracket.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a brushless electric motor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the same brushless motor.

FIG. 3 is a sectional view showing a brushless electric motor according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a brushless electric motor according to a third embodiment of the present invention.

FIG. 5 is a sectional view showing a brushless electric motor according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing a brushless electric motor of a fifth embodiment of the present invention.

FIG. 7 is a sectional view showing a brushless electric motor according to a sixth embodiment of the present invention.

FIG. 8 is a sectional view showing a conventional brushless motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator core 2 Insulating layer 3 Winding 4 Thermosetting resin 5 Stator 6 Rotor 7 Bearing part 8 Bracket 12 Elastomer 13 Flange part 15 Adhesive material 16 Bracket 17 Bearing holding part 18 Elastomer 19 Bracket 20 Bearing holding part 21 Buffer Material 22 Bracket 23 Bearing holding part 24 Synthetic resin 25 Bracket 26 Bearing holding part 27 Elastomer 28 Restraint plate

Claims (6)

[Claims] 1. An annular stator core having a plurality of slots, a winding formed on the stator core via an insulating layer, and a thermosetting material having electrical insulation between the winding and the stator core. A bracket that holds a stator that is integrally molded and solidified with a conductive resin, a rotor that is installed in the center of the stator, and a bearing that supports the rotor and that has a flange An electroless brushless motor in which the bracket is fixed to the stator with an elastomer interposed between the flange portion and the stator. 2. The brushless electric motor according to claim 1, wherein the flange portion of the bracket and the stator are fixed with an adhesive material and then fixed with screws or rivets. 3. The brushless electric motor according to claim 1, wherein an elastomer is vulcanized and adhered to the outside of the bearing holding portion of the bracket. 4. The brushless electric motor according to claim 1, wherein a cushioning material is coated on the outside of the bearing holding portion of the bracket. 5. The brushless electric motor according to claim 1 or 2, wherein the outer side of the bearing holding portion of the bracket is insert-molded with a synthetic resin. 6. The brushless electric motor according to claim 1 or 2, wherein an elastomer having a constraining plate on the outer peripheral portion is vulcanized and adhered to the outside of the bearing holding portion of the bracket.