JP2810003B2 - Small electric motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a small electric motor for a blower,
In particular, it relates to a small motor with a brush .

[0002]

2. Description of the Related Art In a motor with a brush, sliding friction between a brush and a commutator is a source of vibration and noise. For this reason, for example, in the field of small electric motors such as blowers for automobiles, various measures have conventionally been taken. For example, 52
As disclosed in JP-A-24725, a protrusion is provided inside a housing of an electric motor, and an elastic body is attached to an outer edge of a brush holding insulating plate housed in the housing. An elastic coating is formed on the inner wall surface of the brush as disclosed in JP-A-55-23774, JP-A-58-175947, etc. The brush holder is elastically supported by forming an elastic film or by elastically supporting the brush holder through an elastic body interposed between the frame of the motor housing and the end cover as disclosed in Japanese Utility Model Application Laid-Open No. 61-74265. And so on.

[0003]

In recent years, in the field of small motors, parts such as housings have tended to be made of plastic due to the need for weight reduction. When a plastic molded product is used for the motor housing, the rigidity of the housing is significantly reduced as compared with the metal housing (metal frame). The low rigidity of the housing leads to a reduction in vibration absorption efficiency. Therefore, the aforementioned Japanese Utility Model Publication No. 52-24725,
In the elastic body mounting method (method in which an elastic body is interposed between the end frame and the housing) disclosed in Japanese Utility Model Application Laid-Open No. 61-74625, when the housing is made of plastic, vibration from the brush side cannot be sufficiently absorbed by the elastic body. A new problem has arisen.

Further, in this method, the elastic body mounting position of the brush insulating plate is relatively far away from the brush holder, so that indirect vibration suppression for damping vibration at a position far from the brush vibration source is achieved. The minute attenuation ratio tended to decrease.

On the other hand, when an elastic body is provided in a brush holder as disclosed in Japanese Patent Application Laid-Open No. 55-23774, the vibration suppressing means has the highest damping ratio, and the above-mentioned problem can be avoided. There is a problem in that molding causes an increase in cost, and it is technically difficult to control the dimensional accuracy of the elastic film to secure the brush slidability. JP-A-58-175
No. 947 has an intermediate structure between them, but there is a point to be improved in terms of cost and dimensional accuracy control which accompanies the formation of the elastic film similarly to the former. Also,
Conventional brush-related parts include, for example, a holder and a base.
To combine parts that were originally separate parts
Increases assembly time and urges brush to commutator
Since the spring member is inserted in the holder,
It was necessary to secure a space for accommodating the spring member.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to sufficiently satisfy both requirements of plasticization (lightening) of an electric motor housing, a brush holder and its base, and suppression of vibration and noise. It does not require strict dimensional control accuracy of the vibration / noise suppression mechanism.
And improvement of the assemblability of the brush and its related members, the brush
Streamlining of holder space, drawing out conductive wire of brush
And to improve reliability .

[0007]

The present invention employs the following means to achieve the above object.

Hereinafter, the present invention will be described with reference to the embodiment shown in FIG.

That is, the present invention has a brush holder 7 for accommodating and holding a brush 6, and a rotor 5 having a commutator 4 which is in sliding contact with the brush 6, and an output shaft 5a of the rotor 5 is provided at an end of one end of the motor housing 2. In a small electric motor protruding from the cover 3 and allowing the centrifugal fan 1 to be attached to the output shaft 5a, the commutator 4 is arranged on the centrifugal fan 1 side of the rotor 5, and the brush holder 7 is arranged correspondingly. The brush holder 7 is integrally formed of plastic with a base 9 for supporting the holder, together with the base 9, and the motor housing 2 is also formed of plastic. A rigid cylindrical yoke 14 is fixedly arranged, and one end of the brush holder 7 is connected to an end of the cylindrical yoke 14 facing the centrifugal fan 1 via an elastic body 12. Te is pressed against fixed, holder supporting for
The base 9 includes a brush holder 7 and a brush holder.
The drawn positive conductive line 19a and the negative conductive line
19b separately and guided to the connector part 25.
Wire guides 21a and 21b, for holding two helical springs
Are formed integrally with the base 9.
One end 8a of each of the helical springs 8 held on the ridge 18 corresponds to
Brush through the opening provided at the rear end of the brush holder 7
6 has a structure applied to the rear end to elastically support the brush 6
It is characterized by having .

[0010]

According to the above construction, the motor housing 2 can be made of plastic to reduce its weight.
Is fixed to one end of a cylindrical yoke 14 for forming a magnetic circuit, which is disposed on the inner periphery of the housing 2 instead of the low-rigid plastic housing 2. The cylindrical yoke 14 is usually made of iron, and has the highest rigidity among the components of the electric motor, so that the vibration absorbing rate of the elastic body 12 in contact with the yoke 14 increases. Also, the brush holder 7
Is fixed to the yoke 14 via the elastic body 12 so as to absorb vibration at a position very close to the brush 6, so that the vibration damping ratio can be significantly increased. That is, by the above synergistic action, the sliding friction vibration generated between the commutator 4 and the brush 6 receives the most effective vibration damping force. Therefore, the sliding friction vibration generated between the brush 6 and the commutator 4 is sufficiently absorbed by the elastic body 12 and
The transmission to the housing 2 can be effectively suppressed, and the vibration and noise of the electric motor can be reduced while the housing is made plastic. In particular, in order to simplify the manufacturing process and reduce the weight of the entire motor, in addition to the housing 2, the brush holder 7 and its base 9 are made of plastic as a single piece, and the number of low-rigid parts is increased. According to the present invention, low vibration and low noise of the electric motor can be achieved.

In addition, when the centrifugal fan 1 is attached to the rotor 5, the motor introduction space (recess) 1 of the centrifugal fan 1
Although the commutator 4 and the brush 6 of the electric motor are located at a, noise that cannot be absorbed by the elastic body 12 is also agitated by the fan 1 according to such an arrangement, and the centrifugal fan 1 is used as an automobile blower. When used, they are housed and arranged in the scroll casing. Therefore, when the commutator 4 and the brush holder 7 are arranged on the centrifugal fan 1 side, noise that cannot be completely absorbed by the elastic body 12 is also shielded by the scroll casing wall. Therefore, the noise can be further reduced without the noise leaking into the vehicle interior.

When the commutator 4 and the brush holder 7 are arranged on the side of the centrifugal fan 1, the vibration generated by the fan 1 (this vibration is generated by the wind breaking by the fan and the pressure fluctuation in the scroll casing) is generated by the vibration. The commutator 4 and the brush 6 are received at a position close to the source via the output shaft 5a, and without any consideration, the commutator 4 and the brush 6 strongly influence the vibration caused by the fan 1. However, according to the above configuration, the vibration caused by such a fan can be sufficiently absorbed by the elastic body 12 pressed against the yoke 14, so that the commutator 4 and the brush 6 can be smoothly slid in addition to the noise reduction. Guarantee of contact.

In addition, since it is not necessary to apply an elastic body coating which is difficult to form in the brush holder or the like as in the prior art, the elastic body at one end of the brush is simply pressed and fixed to a part of the cylindrical yoke. Mounting can be done easily. further,
The brush base 9 includes related parts of the brush 6, that is, a brush.
Holder 7, conductive wire guides 21a and 21b,
The projection 18 for supporting the neck is integrally formed with the base 9.
Now, work to attach these parts individually to the brush base 9
Is not required, and is assembled inside the motor.
a and 19b are directly and simply connectors on the end cover 3 side
The brush 9 can be pulled out to the commutator 4 side
The urging helical spring 8 is provided with the protrusion 1 outside the brush holder 7.
8, the brush end 8a is attached to the brush 6 rear end.
Since it is applied, the work of assembling the spring is simplified. did
Therefore, while improving the assemblability of the motor parts,
The conductive lines 19a, 19b are controlled by the wire guides 21a, 21b.
Prevention of twisting and insulation improve motor reliability.
Can be Further, the brush 9 is placed in the brush holder 7.
There is no need to interpolate the spring member that biases the
The space in the holder can be rationalized.

[0014]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a partially cutaway sectional view of a case where a small electric motor according to one embodiment of the present invention is applied to an automobile blower.

In FIG. 1, reference numeral 1 denotes a centrifugal fan used for blowing air, 2 denotes a motor housing, and 3 denotes an end cover. The housing 2 and the end cover 3 form an outer shell of the electric motor. The housing 2 and the end cover 3
Is formed of plastic, and a high-rigidity cylindrical yoke 14 for forming a magnetic path of the electric motor is fitted on the inner periphery of the housing 1. 13 is a field pole (stator)
And is fixedly arranged on the inner periphery of the cylindrical yoke 14.

Inside the motor, a rotor 5, a brush 6, a brush holder 7, a holder base 9 and the like with a commutator 4 are incorporated. The output shaft 5a of the rotor 5 projects from the end cover 3 at one end of the motor housing 2, and the output shaft 5a
The centrifugal fan 1 can be attached to the. In the small electric motor according to the present invention, the commutator 4 is arranged on the rotor 5 on the side of the centrifugal fan 1, and the brush holder 7 is arranged correspondingly.

Here, the structure of the brush 6, the brush holder 7, the base 9 and the like will be described with reference to FIG.

FIG. 2 is an exploded perspective view showing the brush holding assembly 10 and the end cover 3 according to the present embodiment. In FIG.
(B) shows a state in which the brush holding assembly 10 is turned upside down.

The base 9 has a rectangular plate shape as is apparent from FIG. 2A, and has a hole 9a formed in the center thereof for inserting the rotor shaft. As shown in FIG. 2B, a pair of rectangular brush holders 7 are arranged on one surface of the base 9 at an interval of 180 °. The brush holder 7 and the base 9 are integrally formed of plastic. As shown in FIG. 1, each brush holder 7 has both ends opened and accommodates the brush 6. The brush 6 is elastically applied at its rear end to an end 8 a of a later-described spring (spring spring) 8. Supported. The number of the helix springs 8 is two corresponding to the number of brushes.

A column (projection) 18 is formed at a position adjacent to each brush holder 7 on the surface of the base 9, and a helix spring 8 is fitted and held on the column 18, and one end 8 a of the spring 8 is connected to the brush holder. The spring end 8a extends to one end (rear end) of the opening of the brush 7 and supports the brush 6 while urging the brush 6 toward the commutator 4. The support column 18 is integrally formed with the base 9 from plastic.

A part of the brush 6 protrudes from the tip of the brush holder 7, and a tongue-like projection 11 is provided on the rear end so as to protrude outward in a state integrated with the brush holder 7. A rectangular elastic body (insulating elastic member) 12 is inserted into the tongue-shaped projection 11.

On the surface of the base 9 on the side opposite to the brush holder,
A second cylindrical elastic body 17 is fixedly arranged at each corner.
This cylindrical elastic body 17 is press-fitted into a projection 16 arranged on the base 9 as shown in FIG.

When such a brush holding assembly 10 is assembled inside the end cover 3, the brush 6 is rotated into the insertion hole 9 a of the base 9 with the end of the brush 6 in contact with the outer peripheral surface of the commutator 4. The elastic body 12 attached to the tongue-shaped protrusion 11 is inserted into the notch recess 15 provided at one end (the centrifugal fan 1 side) of the cylindrical yoke 14, and the base 9 and the end cover 3 are inserted. The second elastic body 17 is interposed between the inside and the inside, and the small flange 3a of the end cover 3 is attached to the motor mounting flange (the large flange 2) on the housing 2 side.
4), and the flanges 3a and 24 are screwed together. According to such mounting, a narrow pressure acts between the end cover 3 and the cylindrical yoke 14, and the elastic compression bodies 12, 17 are appropriately compressed by the narrow pressure.

More specifically, a force from the cylindrical yoke 15 acts on the elastic body 12 and a force from the end cover 3 applies the second elastic body 17, the base 9, the brush holder 7, and the tongue-shaped projection. The elastic body 12 is pressed and fixed to the end surface of the cylindrical yoke 15 by acting through the elastic member 11. The second elastic body 17 is sandwiched between the base 9 and the inside of the end cover 3.

Next, connection of the brush 6 to an external power supply will be described.

As shown in FIG. 2A, the brush holder 7
A notch 7a on one surface of the base 9, a pair of notched grooved projections (conductive wire guides) 21a and 21b on one surface of the base 9, and small holes 23a and 23b and a projection guide 22 on the small flange 3a of the end cover 3. Is formed.

As shown in FIG. 1, an external connection connector 25 is formed on the flange 24 of the housing 2. At the ends of the conductive wires (pigtails) 19a and 19b of each brush, standard terminals 20a and 20
b is attached.

The standard terminals 20a and 20b and the conductive wire 19
a, 19b are notches 7 provided in each brush holder 7
a, guide grooves 21a and 21b of base 9, end cover 3
Ventilation window 3b, projection guide 22 and small hole 23a,
It is inserted and fixed to the external connection connector 25 through 23b. Connection to an external power supply is possible via the external connection connector 25. The conductive wire 19 after the assembly of the brush holding assembly 10 is attached to the commutator side of the base 9.
a, 19b and the commutator 4 to prevent a short circuit.
The protection guide 26 is disposed as shown in FIG.

According to this embodiment, the following effects can be obtained.

First, the motor housing 2, the end cover 3, the brush holder 7, the base 9 and the like are made of plastic molded parts to reduce the weight. Is replaced by a rigid rigid cylindrical yoke 1 instead of the low rigid plastic housing 2.
A structure in which the end face of the base 9 closest to the holder 7 is pressed and fixed to the inside of the end cover 3 through the second elastic body 17 is adopted. The sliding friction vibration generated between the commutators 4 is
The brush 6 is absorbed at a position close to the vibration source with the brush 6 interposed therebetween. Therefore, the most effective vibration damping can be performed,
The effect of suppressing vibration and noise of the electric motor can be improved. In addition, when the centrifugal fan 1 is mounted on the rotor 5, the commutator 4 and the brush 6 of the motor are located in the motor introduction space (recess) 1 a of the centrifugal fan 1. The noise that cannot be absorbed by the elastic body 12 is also agitated by the fan 1, and when the centrifugal fan 1 is used as an automobile blower, it is accommodated and arranged in a scroll casing. In addition, when the brush holder 7 is arranged, noise that cannot be absorbed by the elastic body 12 is shielded by the scroll casing wall, so that noise is not leaked into the vehicle interior and noise reduction is further promoted.

When the commutator 4 and the brush holder 7 are arranged on the side of the centrifugal fan 1, the vibration generated by the fan 1 (this vibration is generated by wind-off by the fan or pressure fluctuation in the scroll casing) is generated by the vibration. The commutator 4 and the brush 6 are received at a position close to the source via the output shaft 5a, and without any consideration, the commutator 4 and the brush 6 strongly influence the vibration caused by the fan 1. However, according to the above configuration, the vibration caused by such a fan can be sufficiently absorbed by the elastic body 12 pressed against the yoke 14, so that the commutator 4 and the brush 6 can be smoothly slid in addition to the noise reduction. Guarantee of contact.

Moreover, the mounting of the elastic bodies 12 and 17 is extremely simple, and the dimensional accuracy is not required to be strict as in the conventional elastic body coating method, which is advantageous in terms of cost.

Second, the connection of the brush 6 to the external connection connector 25 is made by the guide holes 21a, 21a provided in the base 9.
b, the standard terminals 20a, 20b provided at the tips of the conductive wires 19a, 19b may be directly inserted into the connectors 25 by using the ventilation window 3b of the end cover 3, the projection guides 22, the small holes 23a, 23b, and the like. Easy to assemble. Furthermore,
The positive and negative standard terminals 20a and 20b and the conductive wire 19
a, 19b are guide holes 21a, 21b provided in the base 9;
And the projection guide 22 and the small holes 23a, 2 of the end cover.
Since they are separated at 3b, the conductive wires are prevented from being twisted and insulated, and the reliability of the electric motor can be improved.

Third, a holder 7 for supporting a helix spring
The protrusion 18, the conductive wire guides 21a and 21b and the base 9 are
These brush-related parts are integrally molded with plastic.
Parts are assembled together from the beginning into the motor, and the brush
The helical spring 8 that urges the brush 9 toward the commutator 4 is
The brush end 8a is simply inserted into the protrusion 18 outside the
Is applied to the rear end of the brush 6, so that the spring
It is possible to simplify the operation of assembling such a small electric motor . Conventionally, it takes time and effort to assemble the holder, base, and the like to separate them and assemble them.
Since a connector, a harness, and the like are used for connecting conductive wires from the brush to the connector for external connection, simplification in assemblability has been desired. Also, a spring member is provided in the brush holder 7.
The need for interpolation is eliminated, and
Can be streamlined.

As described above, according to the present invention, both the requirements of plasticization (lightening) of the motor housing and the like and suppression of vibration and noise are sufficiently satisfied, and the dimensional control accuracy of the vibration and noise suppression mechanism is strict. Not required and above
Brush-related parts (brush and noise suppression mechanisms)
Holder, holder base, helical spring, helical spring support
Lifting projection, conductive wire guides, etc.) of the assembly is a cost to be advantageous easy and streamlined space of the brush holder
A small motor that can be achieved can be provided.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view showing one embodiment of the present invention.

FIG. 2 is an exploded perspective view of an end cover and a brush holding assembly used in the embodiment.

[Explanation of symbols]

2 ... motor housing, 3 ... end cover, 3b ... ventilation window, 4 ... commutator, 5 ... rotor, 6 ... brush, 7 ... brush holder, 9 ... base, 11 ... brush holder end, 12 ... elastic body, 14 ... cylindrical yoke, 17 ... second elastic body, 19
a, 19b: conductive wire, 20a, 20b: external connection terminal, 21a, 21b: guide hole, 22: projection guide, 23
a, 23b: Small hole, 24: Flange, 25: Connector for external connection.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H02K 5/14 H02K 5/24 H02K 23/00

Claims (1)

(57) [Claims] A brush holder for accommodating and holding a brush;
A rotor having a commutator in sliding contact with the brush,
In a small-sized motor in which an output shaft of the rotor projects from an end cover at one end of the motor housing to allow a centrifugal fan to be attached to the output shaft, the commutator is arranged on the centrifugal fan side of the rotor. The brush holder is arranged correspondingly, the brush holder is integrally formed of plastic on the holder supporting base together with the base, and the motor housing is also formed of plastic, and the magnet of the motor is formed on the inner periphery of the motor housing. A high-rigidity cylindrical yoke that forms a passage is fixedly arranged, and one end of the brush holder is fixed to an end of the cylindrical yoke facing the centrifugal fan via an elastic body . On the base, the brush holder
In addition to the positive conductive wire drawn from the brush holder and the
Separate from the negative side conductive wire and guide it to the connector
The conductive wire guide and two projections for holding the helical spring
It is molded integrally with the base, and each of the
One end of the helical spring is provided at the rear end of the corresponding brush holder
Is applied to the rear end of the brush through the
A small-sized electric motor characterized by having a structure for supporting the electric characteristics .