JPH08275432A - Motor and its manufacturing method - Google Patents

Abstract

PURPOSE: To improve heat dissipation efficiency by exposing at least a covering member and providing a housing consisting of a rotor, a stator, and a synthetic resin material for covering a circuit substrate. CONSTITUTION: A covering member 33 consisting of silicon material is arranged in a power IC 30 while covering a range including the power IC 30, a heat sink 31, and a connection part. A stator 25, a rotor 28, and a rotary substrate 29 form a housing 34 while they are molded by a synthetic resin material and the housing 34 is covered with the covering member 33 so that the covering member 33 is exposed externally from the housing 34. Heat generated during operation from such circuit element as the power IC 30 is radiated externally via the covering member 33 as shown by arrows.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor and a method of manufacturing the same, and more particularly, to a motor having a structure for satisfactorily radiating heat from a circuit element for driving the motor, and reliability of parts such as a circuit element during manufacturing. The present invention relates to a motor manufacturing method that can be improved.

[0002]

2. Description of the Related Art FIG. 9 is a sectional view taken along the axis of a conventional motor 1, and FIG. 10 is a plan view of the motor 1.
1 is a cross-sectional view of the vicinity of a circuit element mounted on the circuit board of the motor 1. The configuration of the motor 1 will be described below with reference to FIGS. 9 to 11.

The motor 1 is a rotor including a stator 5 having a plurality of stator coils 4 arranged in a circumferential direction in a case 3 fixed to a stator core 2, a permanent magnet 6 having a plurality of poles, and a rotary shaft 7. 8 and. The circuit board 9 is fixed to the case 3, and the circuit board 9 includes a power IC (integrated circuit) 10 having a power transistor for supplying a drive current to the stator coil 4 and the like. A circuit element (not shown) is mounted.
A heat sink 11 is provided on the power IC 10. The heat dissipation plate 11 also serves as a ground electrode of the power IC 10 and is electrically connected to a ground printed wiring formed on the circuit board 9. The connection terminals 10a of the power IC 10 are electrically and mechanically connected to the printed wiring on the circuit board 9 at the connection portions 20 by soldering. These stators 5,
The rotor 8 and the circuit board 9 are covered with a housing 12 formed by molding a synthetic resin material. A flange 1 is provided on the outer circumference at one end of the housing 12 in the axial direction.
3 is formed, and the through hole 14 is formed. Power IC
The heat generated from the circuit elements such as 10 during its operation is
As shown by the arrow in FIG. 11, heat is radiated to the outside through the housing 12.

[0004]

In the conventional motor 1 as described above, the housing 12 covers the entire circuit board 9 and the power IC 10 and the control circuit element, so that heat from the power IC 10 and the like is generated. The housing 12 made of a synthetic resin material does not radiate heat well, and the temperature locally rises on the circuit board 9. When the temperature of the IC becomes excessive, the characteristics of the IC change, the designed operation becomes difficult, and the IC may be thermally destroyed. Therefore, it is necessary to use the motor 1 within a range in which the temperature of the IC does not rise excessively, and there is a problem that the output of the motor 1 cannot be greatly increased.

Further, in the prior art for improving the heat radiation efficiency by installing a heat radiation plate formed of, for example, an iron plate or an aluminum plate on the power IC 10, the power I
Since the heat dissipation plate 11 also serving as the ground electrode of C10 is not electrically insulated from the outside, an electric insulation process from the outside is performed to prevent static electricity from entering the heat dissipation plate such as the iron plate from the outside. However, there is a problem in that usability is low because special consideration needs to be taken when mounting the motor 1.

FIG. 12 is a sectional view taken along the axis of another conventional motor 1a. Hereinafter, the other conventional motor 1a will be described with reference to FIG. Motor 1a
Is a configuration in which the sirocco fan 13 is provided in the motor 1 described with reference to FIGS. 9 to 11. The sirocco fan 13 is coaxially fixed to the rotary shaft 7 of the rotor 8, and a fan case 15 made of metal such as an iron plate is provided so as to surround the sirocco fan 13. The fan case 15 is a screw 16 inserted through the through hole 14 of the housing 12.
Then, it is fixed to the housing 12. At this time, a gap 19 having a space d is often formed between the end surface 17 of the housing 12 facing the fan case 15 and the end surface 18 of the fan case 15 facing the housing 12.

In such a motor 1a, since the gap 19 is formed, the thermal resistance between the end surface 17 of the housing 12 facing the fan case 15 and the end surface 18 of the fan case 15 facing the housing 12 is high. Becomes
There is a problem that the heat from the power IC 10 cannot be satisfactorily dissipated. Further, when the fan case 15 is attached to the housing 12, the size of the gap 19 varies for each motor 1a, and thus the thermal resistance varies. As a result, there is a problem in that the efficiency of heat dissipation from the power IC 10 varies among the motors 1a, and the output characteristics vary among the motors 1a.

When the motors 1 and 1a are manufactured, the housing 12 is formed by molding synthetic resin by injection molding or the like. The pressure of the molten synthetic resin at the time of injection is It directly adds to circuit elements such as the power IC 10. Due to this pressure, the circuit element may be deformed and the reliability of the circuit element may be reduced. Also,
The circuit element such as the power IC 10 is connected to the land portion of the printed wiring of the circuit board 9 by the connection portion 20 by soldering. During the molding, the expansion of the high temperature synthetic resin during injection and the contraction of the synthetic resin during cooling exert a pressure on the connection portion 20 due to the expansion and contraction of the synthetic resin. As a result, the connection portion 20 may be deformed or peeled off, and the reliability of the electrical or mechanical connection between the circuit element such as the power IC 10 and the circuit board 9 may be reduced.

The inventions of claims 1 and 2 have been made to solve the above-mentioned technical problems, and the purpose thereof is to improve the efficiency of heat dissipation from the circuit element, and to improve the motor. It is to provide a motor capable of greatly increasing the output of.

The invention of claim 3 is to solve the above-mentioned technical problem, and its purpose is to face the end face of the housing made of synthetic resin material facing the fan case and the housing of the fan case. (EN) Provided is a motor that can reduce the thermal resistance between the end face and the heat dissipation from the circuit element, and the size of the gap varies from motor to motor. It is an object of the present invention to provide a motor that prevents the occurrence of the above and prevents the output characteristics of the motor from varying.

The invention of claim 4 was made to solve the above-mentioned technical problem, and the purpose thereof is to eliminate the necessity of performing an electrical insulation treatment with the outside and improve the usability. Further, the pressure of the molding material at the time of molding is prevented from being directly applied to the circuit element, the reliability of the circuit element can be improved, and the connection between the circuit element and the circuit board is accompanied by the molding material caused by the temperature change at the time of molding. It is an object of the present invention to provide a method for manufacturing a motor, which is capable of preventing the pressure from being applied during expansion and contraction and improving the reliability of electrical connection and mechanical connection of the connection portion.

A fifth aspect of the present invention is made to solve the above-mentioned technical problem, and an object thereof is to face an end surface of a housing made of a synthetic resin material facing the fan case and the housing of the fan case. (EN) Provided is a method for manufacturing a motor capable of reducing the thermal resistance between the end face and the heat dissipation from a circuit element, and the size of the gap is different for each motor. It is an object of the present invention to provide a method for manufacturing a motor, which prevents variations in the output characteristics of the motor and prevents variations in the output characteristics of the motor.

[0013]

According to another aspect of the present invention, there is provided a motor, a rotor and a stator, a circuit board on which a circuit element for supplying a drive current to the stator is mounted, and at least a part of the circuit element. And a housing made of a synthetic resin material that covers at least the covering member and covers the rotor, the stator, and the circuit board. It is possible to achieve the above object.

According to the second aspect of the invention, the covering member is a molded product made of a silicon material, whereby the above object can be achieved.

According to a third aspect of the present invention, a fan rotated by the rotor and a fan case surrounding the fan are provided on one axial end of the rotor, and the covering member rotates the rotor. The fan case is exposed at one end side in the axial direction, and the fan case is provided in contact with the covering member,
Thereby, the above object can be achieved.

According to a fourth aspect of the present invention, there is provided a motor manufacturing method, wherein a covering member made of a material having high thermal conductivity and high electric insulation is fixed to a circuit element mounted on the circuit board, and the circuit board and the stator. And a step of fixing the circuit board and the stator to each other with a synthetic resin material so that the covering member is exposed to form a housing, thereby achieving the above object. can do.

According to a fifth aspect of the present invention, in the molding step, the circuit element mounted on the circuit board disposed on one axial end of the rotor is covered with a protrusion on the axial one end. A cover member provided with a portion, molded so that the convex portion protrudes from the housing, and a fan rotated by the rotor on one axial end side, and a fan case surrounding the fan. Is provided so that the fan case comes into contact with the covering member, whereby the above object can be achieved.

[0018]

In the motor according to the first aspect of the present invention, the circuit element mounted on the circuit board is at least partially covered with the covering member made of a material having high thermal conductivity and high electric insulation. Further, the rotor, the stator, and the circuit board are covered with a housing made of a synthetic resin material so that at least the covering member is exposed. In this way, since the covering member covering the circuit element on the circuit board is exposed to the outside from the housing, the heat from the circuit element is radiated favorably to the outside by the covering member. This prevents a situation where the temperature locally rises on the circuit board. Therefore, it is possible to prevent the temperature of the circuit element from rising excessively, prevent the characteristic of the circuit element from changing due to the temperature, and always realize the designed operation.
Moreover, the situation in which the circuit element is thermally destroyed is prevented. Therefore, the motor can be used without considering the temperature rise of the circuit element, and the output of the motor can be greatly increased.

Further, as compared with a technique of disposing a heat radiating plate formed of an iron plate or an aluminum plate on the circuit element as an example, the heat radiating plate is electrically connected to the outside so that static electricity or the like does not flow from the outside. The need for insulation treatment is eliminated, no special consideration is required when mounting the motor, and usability is significantly improved.

In the invention of claim 2, a molded article made of a silicon material is used as the covering member. Thereby, the above object can be achieved.

In the third aspect of the present invention, a fan rotated by the rotor and a fan case surrounding the fan are provided on one axial end side of the rotor. At this time, the covering member is exposed on one axial end side of the rotor, and the fan case is provided in contact with the covering member. As a result, the invention of this claim can further realize the following operation in addition to the operation of the invention of claim 1. According to the present invention, it is possible to prevent a gap from being formed between the end surface of the fan case facing the housing and the end surface of the covering member exposed from the housing. Therefore, the thermal resistance between the covering member and the fan case can be remarkably reduced, the heat from the circuit element can be quickly transferred to the fan case, and the heat can be effectively dissipated from the circuit element.

Further, in the present invention, it is possible to prevent a gap from being formed between the end surface of the fan case facing the housing and the end surface of the covering member exposed from the housing.
It is possible to solve the problem that the output characteristic varies from motor to motor due to the variation in the size of the gap generated in the related art.

In the motor manufacturing method of the fourth aspect of the present invention, a covering member made of a material having high thermal conductivity and high electric insulation is fixed to the circuit element mounted on the circuit board, and the circuit board and the stator are fixed. Fix to each other. Next, the circuit board and the stator are molded with a synthetic resin material so that the covering member is exposed to form a housing. As a result, when molding the housing with synthetic resin,
The pressure of the molten synthetic resin at the time of formation is absorbed by the coating member, and this pressure is prevented from being directly applied to the circuit element. Therefore, the deformation of the circuit element is prevented, and the reliability of the circuit element is improved.

Further, in the present invention, the pressure due to the expansion of the high temperature synthetic resin during the molding and the contraction of the synthetic resin during the cooling is absorbed by the covering member, and this pressure is applied to the connecting portion between the circuit element and the circuit board. The situation of directly joining is prevented. Therefore, the pressure prevents the connection portion from being deformed or peeled off, and the reliability of the electrical or mechanical connection between the circuit element and the circuit board is significantly improved.

In the invention of claim 5, in addition to the operation of the invention of claim 4, the following operation can be further realized. In the present invention, it is possible to prevent a gap from being formed between the end surface of the fan case facing the housing and the end surface of the covering member protruding from the housing. Therefore, the thermal resistance between the covering member and the fan case can be remarkably reduced, the heat from the circuit element can be quickly transferred to the fan case, and the heat can be effectively dissipated from the circuit element.

Further, in the present invention, a gap is prevented from being formed between the end surface of the fan case facing the housing and the end surface of the covering member protruding from the housing.
It is possible to solve the problem that the output characteristic varies from motor to motor due to the variation in the size of the gap generated in the related art.

[0027]

1 is a sectional view taken along the axial direction of a motor 21 according to a first embodiment of the present invention, FIG. 2 is a plan view of a portion of the motor 21, and FIG. 3 is mounted on a circuit board of the motor 21. It is sectional drawing of the circuit element vicinity. Below,
The configuration of the motor 21 will be described with reference to FIG. Although the present embodiment is described with respect to a 4-pole DC brushless motor as an example, other types of motors will also be described.
The present invention is easily implemented.

The motor 21 includes a stator 25 having a plurality of stator coils 24 arranged in a circumferential direction in a case 23 fixed to a stator core 22, and a permanent magnet 26 having a plurality of poles.
And a rotor 28 including a rotary shaft 27. A circuit board 29 is fixed to the case 23,
A power IC (integrated circuit) 30 having a built-in power transistor for supplying a drive current to the stator coil 24 and a control circuit element (not shown) for controlling the rotation of the motor 21 are mounted on this. The power IC 30 is provided with a heat dissipation plate 31. The heat sink 31 is a power IC
It also serves as a ground electrode of 30 and is electrically connected to a ground printed wiring formed on the circuit board 29. Further, the connection terminal 32 of the power IC 30 is electrically and mechanically connected to the land portion of the printed wiring formed on the circuit board 29 at a connection portion 47 by soldering, for example.

The power IC 30 includes, for example, a covering member made of a silicon material such as a silicon resin (as an example,
33 (using a sircon under the trade name) is arranged so as to cover the range including the power IC 30, the heat dissipation plate 31, and the connecting portion 47. The stator 25, the rotor 28, and the circuit board 29 are a housing 34 formed by molding with a synthetic resin material as described later, and the covering member 33 is covered so as to be exposed from the housing 34 to the outside. .
A flange 35 is formed on the outer periphery of one end of the housing 34 in the axial direction, and a through hole 36 is formed. The heat generated from the circuit elements such as the power IC 30 during its operation is radiated to the outside through the covering member 33, as indicated by the arrow in FIG.

FIG. 4 is a perspective view showing a part of the manufacturing process of the motor 21 of one embodiment of the present invention, FIG. 5 is a sectional view showing a part of the manufacturing process, and FIG. 6 is the manufacturing process. FIG. 4 is a cross-sectional view for explaining in more detail. The manufacturing process of this embodiment will be described below with reference to FIGS. Before molding and forming the housing 34, FIG.
, The power IC 30 on the circuit board 29,
The covering member 33 formed in a shape that covers the area including the heat dissipation plate 31 and the connecting portion 47 is fixed to the circuit board 29 by, for example, screwing. Next, as shown in FIG. 5B, the molding described above is performed to form the housing 34. Details of the molding process are shown in FIG.

As shown in FIG. 6A, the circuit board 29 to which the covering member 33 is fixed is fixed to the stator 25. Next, as shown in FIG. 6B, the stator 25 to which the circuit board 29 is fixed is attached to the upper mold 37 and the lower mold 38.
Place between. At this time, as described above, the upper end surface of the covering member 33 is brought into close contact with the upper mold 37 so that the covering member 33 is exposed to the outside from the housing 34. A synthetic resin material in a molten state is injected into the cavity 39 between the upper mold 37 and the lower mold 38 as an example. Upper mold 37 and lower mold 38
Are separated from each other, and as shown in FIG.
The circuit board 29 and the circuit board 29 are molded in the housing 34, and the covering member 33 is exposed from the housing 34 to the outside.

The motor 21 having such a structure can achieve the following effects. In the motor 21 of the present embodiment having the above-described configuration, the covering member 33 that covers the range including the power IC 30, the heat dissipation plate 31, and the connecting portion 47 on the circuit board 29 is exposed to the outside from the housing 34. Therefore, the heat from the power IC 30 and the like is satisfactorily radiated to the outside by the covering member 33. This prevents a situation where the temperature locally rises on the circuit board 29. Therefore, it is possible to prevent the temperature of the power IC 30 from rising excessively, prevent the characteristic of the IC from changing due to the temperature, and always realize the designed operation. Also, the situation where the IC is thermally destroyed is prevented.
Therefore, the motor 21 can be operated without considering the temperature rise of the IC.
Can be used, and the output of the motor 21 can be greatly increased.

Further, as compared with the prior art in which a heat dissipation plate formed of an iron plate or an aluminum plate is installed on the power IC 30 as an example, electricity from the outside is prevented so that static electricity or the like does not flow into the heat dissipation plate from the outside. This eliminates the need to perform a static insulation process, eliminates the need for special consideration when mounting the motor 21, and significantly improves usability.

In the manufacturing method of this embodiment, when the housing 34 is formed by molding a synthetic resin by injection molding or the like, the pressure of the molten synthetic resin at the time of injection is absorbed by the covering member 33. The situation in which this pressure is directly applied to the circuit elements such as the power IC 30 is prevented. Therefore, the reliability of circuit elements such as the power IC 30 is improved.

Further, as described above, the circuit element such as the power IC 30 is connected to the land portion of the printed wiring of the circuit board 29 by the connecting portion 47 by soldering. In the present embodiment, the pressure due to the expansion of the high temperature synthetic resin at the time of injection and the contraction of the synthetic resin at the time of cooling is absorbed by the covering member 33 during the molding, and this pressure is printed with the circuit element such as the power IC 30. The situation where it is directly applied to the connection portion 47 with the wiring is prevented. Therefore, it is possible to prevent the soldering portion of the connection portion 47 from being deformed or the connection terminal 32 and the land portion of the circuit board 29 to be forcibly separated from each other by the pressure due to the expansion and contraction of the synthetic resin, and the power is prevented. The reliability of electrical or mechanical connection between the circuit element such as the IC 30 and the circuit board 29 is significantly improved.

FIG. 7 shows a motor 21a according to the second embodiment of the present invention.
It is a sectional view of a part along the axis of. The configuration of the motor 21a of this embodiment will be described below with reference to FIG.
The motor 21a has a configuration in which a sirocco fan 40 is added to the configuration of the motor 21 of the first embodiment, and a covering member 33 is protruded from the housing 34 by a height d1 as described in detail in a manufacturing method described later. Is. That is, in the present embodiment, instead of the covering member 33 of the first embodiment described with reference to FIGS. 1 to 6, the convex portion 46 having the height d1 is provided on the top of the covering member 33 of the first embodiment. The formed covering member 33a is used.

The sirocco fan 40 is coaxially fixed to the rotary shaft 27 of the rotor 28, and a fan case 41 made of metal such as an iron plate is provided so as to surround the sirocco fan 40. The fan case 41 is the housing 34
With the screw 42 inserted through the through hole 36 of
Has been fixed. At this time, the end surface 43 of the fan case 41 facing the housing 34 projects from the end surface 44 of the housing 34 facing the fan case 41.
And is arranged in contact with the convex portion 46. The contact of the fan case 41 with the covering member 33a is caused by the contact between the end surfaces 43, 4 and 4.
The length of the covering member 33a exceeds the assumed maximum amount of the gap described in the prior art that may occur between the above-mentioned covering members 33a.
It can be easily realized by determining the protrusion amount d1 of the housing 34 from the housing 34.

FIG. 8 is a sectional view showing the manufacturing process of this embodiment. From the housing 34 to the convex portion 4 of the covering member 33a
The configuration in which 6 is projected can be obtained as follows. As shown in FIG. 8 (1), an upper mold 37a having a recess 45 formed in a portion corresponding to the covering member 33a is used. The other structure of the upper mold 37a is the same as the upper mold 37 of the first embodiment.
The same lower mold as the lower mold 38 of the first embodiment is used. As described above, the depth d of the recess 45 is selected to be larger than the assumed maximum amount of the gap described between the end faces 43 and 44 and described in the prior art. The structure in which the covering member 33a, the circuit board 29 and the stator 25 are integrated is sandwiched between the upper mold 37a and the lower mold having the same shape as the lower mold 38 in the first embodiment, and the covering member 33a is formed in the recess 45. The protrusion 46 is inserted. Thereafter, as shown in FIG. 8B, the housing 34 is formed by injection molding. As a result, the protrusion 46 can be projected from the end surface 44 of the housing 34 by the height d1. After this, as shown in FIG. 8C, the sirocco fan 40
Is attached to the rotary shaft 27, and the fan case 41 is attached to the housing 34. At this time, the end surface 43 of the fan case 41 comes into contact with the convex portion 46 of the covering member 33 protruding from the housing 34 by the protrusion amount d1.

In the motor 21a of this embodiment as described above, the following effects can be further realized in addition to the effects realized by the first embodiment.

In the prior art described with reference to FIG. 12, between the end face 17 of the housing 12 facing the fan case 15 and the end face 18 of the fan case 15 facing the housing 12 is the fan in this embodiment. Case 41
Between the end surface 43 of the housing 34 facing the housing 34 and the end surface 44 of the housing 34.
Due to the contact between the convex portion 46 of 3a and the fan case 41,
A situation in which a gap is formed between the end faces 43 and 44 is prevented. Therefore, the thermal resistance between the fan case 41 and the covering member 33a can be significantly reduced, and the power IC
The heat from the power IC 30 quickly moves to the fan case 41, and the heat from the power IC 30 can be dissipated well.

Further, in the present embodiment, the fan case 4
End face 43 facing the housing 34 of No. 1 and the housing 34
Since a gap is prevented from being formed between the convex portion 46 of the covering member 33a protruding from the above, the size of the gap in the conventional technique varies from motor to motor, and thus the output characteristics of the motor vary. The problem is resolved.

Further, the structure and manufacturing method described in the above embodiments show each embodiment of the present invention, and do not limit the scope of the present invention. The present invention includes a wide range of modifications without departing from the spirit of the present invention.

[0043]

As described above, according to the invention of claim 1,
Since the covering member made of a material having high thermal conductivity and electrical insulation covering the circuit element on the circuit board is exposed to the outside from the housing, the heat from the circuit element can be favorably transferred to the outside by the covering member. Heat is dissipated. This prevents a situation where the temperature locally rises on the circuit board. Therefore, the situation where the temperature of the circuit element rises excessively is prevented, the change in the characteristics of the circuit element due to the temperature is prevented,
The designed operation can always be realized. Moreover, the situation in which the circuit element is thermally destroyed is prevented. Therefore, the motor can be used without considering the temperature rise of the circuit element, and the output of the motor can be greatly increased.

Further, as compared with a technique of disposing a heat radiating plate formed of an iron plate or an aluminum plate on the circuit element as an example, an electrical connection with the outside is made so that static electricity or the like does not flow into the heat radiating plate from the outside. The need for insulation treatment is eliminated, no special consideration is required when mounting the motor, and usability is significantly improved.

In the invention of claim 2, a molded product made of a silicon material is used as the covering member. The effect of claim 1 can also be achieved by this invention.

According to the third aspect of the present invention, the covering member is exposed on one axial end side of the rotor, and the fan case is provided in contact with the covering member. Thereby, the present invention
In addition to the effects of the invention of claim 1, the following effects can be further realized. According to the present invention, it is possible to prevent a situation in which a gap is formed between the end surface of the fan case facing the housing and the end surface of the covering member exposed from the housing. Therefore, the thermal resistance between the covering member and the fan case can be remarkably reduced, the heat from the circuit element can be quickly transferred to the fan case, and the heat can be effectively dissipated from the circuit element.

Further, in the present invention, a gap is prevented from being formed between the end surface of the fan case facing the housing and the end surface of the covering member exposed from the housing.
It is possible to solve the problem that the output characteristic varies from motor to motor due to the variation in the size of the gap generated in the related art.

According to the fourth aspect of the present invention, when the housing is molded by molding with the synthetic resin, the pressure of the molten synthetic resin at the time of formation is absorbed by the covering member. Therefore, the situation where this pressure is directly applied to the circuit element is prevented. Therefore, the deformation of the circuit element is prevented, and the reliability of the circuit element is improved. Further, in the present invention, the pressure due to the expansion of the high temperature synthetic resin during the molding and the contraction of the synthetic resin during the cooling is absorbed by the covering member, and this pressure is directly applied to the connecting portion between the circuit element and the circuit board. Is prevented. Therefore, the pressure prevents the connection portion from being deformed or peeled off, and the reliability of the electrical or mechanical connection between the circuit element and the circuit board is significantly improved.

According to the invention of claim 5, in addition to the effect of the invention of claim 4, the following effect can be further realized. In the present invention, it is possible to prevent a gap from being formed between the end surface of the fan case facing the housing and the end surface of the covering member protruding from the housing. Therefore, the thermal resistance between the covering member and the fan case can be remarkably reduced, the heat from the circuit element can be quickly transferred to the fan case, and the heat can be effectively dissipated from the circuit element.

Further, in the present invention, it is possible to prevent a gap from being formed between the end surface of the fan case facing the housing and the end surface of the covering member protruding from the housing.
It is possible to solve the problem that the output characteristic varies from motor to motor due to the variation in the size of the gap generated in the related art.

[Brief description of drawings]

FIG. 1 is a sectional view taken along an axial direction of a motor 21 according to a first embodiment of the present invention.

FIG. 2 is a plan view of a part of a motor 21.

FIG. 3 is a sectional view of the vicinity of a circuit element mounted on a circuit board of a motor 21.

FIG. 4 is a perspective view showing a part of the manufacturing process of the motor 21 according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a part of the manufacturing process of the present embodiment.

FIG. 6 is a cross-sectional view for explaining the manufacturing process in more detail.

FIG. 7 is a partial cross-sectional view taken along the axis of a motor 21a according to a second embodiment of the present invention.

FIG. 8 is a cross-sectional view showing the manufacturing process of the present embodiment.

FIG. 9 is a sectional view taken along the axis of the conventional motor 1.

FIG. 10 is a plan view of the motor 1.

FIG. 11 is a cross-sectional view of the vicinity of a circuit element mounted on the circuit board of the motor 1.

FIG. 12 is a sectional view taken along the axis of another conventional motor 1a.

[Explanation of symbols]

 21, 21a Motor 22 Stator Core 24 Stator Coil 25 Stator 27 Rotating Shaft 28 Rotor 29 Circuit Board 30 Power IC 31 Heat Sink 32 Connection Terminals 33, 33a Covering Member 34 Housing 37, 37a Upper Model 38 Lower Model 40 Sirocco Fan 41 Fan Case 43, 44 End face 45 Recess 46 Convex 47 Connection

Claims (5)

[Claims] 1. A rotor and a stator, a circuit board on which a circuit element for supplying a driving current to the stator is mounted, and a circuit board at least partially covering the circuit element, which has thermal conductivity and electrical insulation. A motor comprising: a covering member made of a high material; and a housing made of a synthetic resin material that exposes at least the covering member and covers the rotor, the stator, and the circuit board. 2. The motor according to claim 1, wherein the covering member is a molded product made of a silicon material. 3. A fan which is rotated by the rotor and a fan case which surrounds the fan are provided on one end side in the axial direction of the rotor, and the covering member is the axial direction of the rotor. The motor according to claim 1, wherein the fan case is exposed on one end side and is provided in contact with the covering member. 4. A step of fixing a covering member made of a material having high thermal conductivity and electrical insulation to a circuit element mounted on a circuit board, and fixing the circuit board and the stator to each other, and the circuit. Molding the substrate and the stator with a synthetic resin material so that the covering member is exposed to form a housing. 5. In the step of molding, the circuit element mounted on the circuit board disposed on one axial end side of the rotor is covered, and the convex portion is provided on the axial one end side. The cover member is molded so that the convex portion protrudes from the housing, and a fan that is rotated by the rotor and a fan case that surrounds the fan are provided on one end side in the axial direction of the fan case. 5. The method for manufacturing a motor according to claim 4, further comprising: providing the motor so as to contact the covering member.