JP2004159464A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor wherein temperature rise can be effectively suppressed. <P>SOLUTION: The motor 21 comprises a metal housing 24 which encircles a rotor 29 rotatably driven; a fan 50 which is disposed on one side in the direction of the axis of the housing 24, and is rotatably driven in conjunction with the rotor 29; a radiator plate 31 which is disposed under the housing 24 at a distance, and has a plurality of fins 33 extending toward the housing 24; and a wiring board 41 which is disposed on the radiator plate 31 opposite to the housing 24, and is mounted with electronic circuit components 38 on the radiator plate 31 side in contact with or in proximity to the radiator plate 31. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a motor, and more particularly, to a motor having a function of suppressing a temperature rise of the motor.
[0002]
[Prior art]
As a conventional technique relating to such a technique for suppressing a temperature rise of a motor, a technique using a heat radiating plate is known (for example, see Patent Document 1).
[0003]
FIG. 9 is a partial cross-sectional view of the brushless motor of Patent Document 1.
[0004]
Hereinafter, this brushless motor will be described with reference to FIG.
[0005]
The brushless motor holds the bearings 13 and 14 in the housing 2. The plate 1 holds the printed circuit board 9 and holds the housing 2 by caulking. The core 3 is provided with a winding 5 via an insulating layer 4 to form a stator. The screw 10 penetrates the core 3 and is fastened to the housing 2 to fix the stator and the housing 2 by pressure.
[0006]
A rotor frame 7 having a magnet arranged in the outer circumferential direction of the core 3 with a gap therebetween is fixedly pressed into the rotor shaft 6 and is press-fitted and fixed to the inner rings of bearings 13 and 14 having outer rings held by the housing 2. You. The electronic component 8 is mounted on a printed circuit board 9 fixed to the heat radiating plate 15 by screws 11. The fan 12 is fixed to the rotor shaft 6.
[0007]
In such a brushless motor, the winding generates heat in proportion to the magnitude of the current flowing through the winding, and the generated heat is transmitted to the plate 1 via the core 3 and the housing 2. On the other hand, the cooling air from the fan 12 rotating integrally with the rotor shaft 6 cools the housing 2 and the plate 1 to prevent the temperature of the winding from rising.
[0008]
[Patent Document 1]
JP-A-08-033279 (page 2-3, FIG. 1)
[0009]
[Problems to be solved by the invention]
In the brushless motor disclosed in Patent Document 1, heat generated by the coil is transmitted to the printed circuit board 9 or transmitted to the plate 1 via the housing 2 or the printed circuit board 9. The plate 1 and the printed circuit board 9 are cooled by the cooling air from the fan 12 to cool the coil. Also, the heat generated in the electronic component 8 is transmitted to the printed circuit board 9 and the plate 1 as described above, and is cooled as described above.
[0010]
At this time, the connection between the plate 1 and the printed circuit board 9 and the connection between the plate 1 and the rotor frame 7 are via the housing 2. It is said that there is an air layer between the rotor frame 7 and the rotor frame 7, heat transfer from the rotor frame 7 or the printed circuit board 9 to the plate 1 is insufficient, and it is difficult to sufficiently cool the electronic circuit 8. There is a problem.
[0011]
Such a problem is that when the electronic circuit 8 uses an FET (field effect transistor) as a switching circuit for rotationally driving the brushless motor, it is necessary to flow a relatively large current in order to obtain a high output. The degree of temperature rise increases. In such a case, the above problem becomes more remarkable.
[0012]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a motor capable of effectively suppressing a temperature rise.
[0013]
[Means for Solving the Problems]
The invention according to claim 1 is a metal housing having a stator and a rotor, a fan outside the housing, coaxially connected to the rotor and driven to rotate, and a fan mounted on a lower side of the housing. A radiator plate arranged at intervals, a plurality of fins extending from one surface of the radiator plate toward the housing, and a wiring board arranged at an interval on the other surface side of the radiator plate, An electronic circuit component mounted on the wiring board and in contact with or in proximity to the heat sink.
[0014]
The invention according to claim 2 is the motor according to claim 1, wherein the heat radiating plate is arranged around the entire circumference of the housing.
[0015]
The invention according to claim 3 is the motor according to claim 1 or 2, wherein a lead wire is connected to a lower side of the wiring board. The invention according to claim 4 is the motor according to any one of claims 1 to 3, wherein the heat sink and the wiring board are fixed by a needle pin and a push nut.
[0016]
The invention according to claim 5 is the motor according to claim 4, wherein a spring washer or a spring is disposed between the heat sink and the wiring board.
[0017]
The invention according to claim 6 is the motor according to any one of claims 1 to 5, wherein the motor is a brushless DC motor.
[0018]
[Operation]
According to the first aspect of the present invention, when the motor is driven to rotate and the electronic circuit component generates heat, the heat from the electronic circuit component is dissipated from the electronic circuit component and is transmitted to the wiring board on which the electronic circuit component is mounted. Is transmitted. Since the electronic circuit component is in contact with or close to the heat sink, heat from the electronic circuit component is transmitted to the heat sink. The fins of the heat sink extend toward the housing. The housing, the fins, the heat sink, and the wiring board are cooled by cooling air from a fan disposed on one side in the axial direction of the housing.
[0019]
Here, since the electronic circuit component is in contact with or close to the heat sink, the heat from the electronic circuit component is effectively transmitted to the heat sink, and the heat of the heat sink is effectively cooled by the fins. Thereby, the temperature rise of the motor can be effectively suppressed. In addition, since the fins of the heat sink extend toward the housing, the heat generated in the motor is effectively transmitted to the heat sink through the fins, and in this respect, it is also possible to effectively suppress the temperature rise of the motor. Can be.
[0020]
In the case of the motor according to the second aspect, since the heat radiating plate is arranged over the entire circumference of the housing, heat is more effectively transmitted from the housing to the heat radiating plate. It can be further improved.
[0021]
In the case of the motor according to the third aspect, even if the heat generated from the electronic circuit components and the housing increases, the lead wire is connected to the lower side of the wiring board, so that the operation and effect according to the first aspect can be realized. In addition, it is possible to prevent the lead wire from being deteriorated or damaged by the influence of the heat.
[0022]
In the case of the motor according to the fourth and fifth aspects, since the necessity of screwing the heat sink and the wiring board to each other is eliminated, the number of parts and the number of working steps required for mutual fixing of both are reduced.
[0023]
In the case of the motor described in claim 6, these functions and effects can be realized for a DC brushless motor.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the invention will be described with reference to the drawings.
[0025]
(First embodiment)
1 to 4 show a brushless DC motor (hereinafter, motor) 21 according to a first embodiment of the present invention.
[0026]
The motor 21 is a motor used for a motor for an electric tool, a motor for industrial equipment, a motor for a radio control, and a motor for a vehicle.
[0027]
FIG. 1 is a front view showing a partial cross section of the motor 21 of the first embodiment, FIG. 2 is a right side view of FIG. 1, FIG. 3 is a bottom view of the motor 21, and FIG. FIG.
[0028]
Hereinafter, the configuration of the motor 21 of the present embodiment will be described with reference to FIGS.
[0029]
In the motor 21, a coil 23 is wound around a ring-shaped stator core 22 to constitute a stator 25, and is housed in a cylindrical metal housing 24. Further, a rotor 29 is disposed on the inner periphery of the stator 25.
[0030]
A bracket 26 formed integrally with the cylindrical housing 24 is disposed on one axial side of the stator 25, and a bearing 27 is fitted to the bracket 26. A similar bearing (not shown) is provided on the opposite side in the axial direction. And, the rotating shaft 30 of the rotor 29 is rotatably supported.
[0031]
A sensor board 34 is fixed in the housing 24, and an electronic circuit element 35 such as a Hall element is mounted on the sensor board 34.
[0032]
An aluminum radiator plate 31 is fixed to the lower peripheral surface of the housing 24 with screws 32. As shown in FIG. 2, a plurality of fins 33 extending toward the housing 24 are integrally provided on the upper surface of the heat sink 31. A pair of support legs 36 and 37 extending downward from both sides of the lower surface of the heat sink 31 are integrally formed.
[0033]
An inner peripheral portion near the distal end of the support leg 36 is engaged with an outer peripheral edge of a power board 41 which is a wiring board on which an electronic circuit element 38 through which a relatively large current flows, such as an inverter circuit or a power supply circuit, is mounted. In this case, a stepped portion 42 having a square shape is formed. In the vicinity of the tip of the other support leg 37, a square step 43 is formed so as to engage with the outer peripheral edge of the power board 41, and the power board 41 is sandwiched between the step 43 and the step 43. Engaging claw 44 is formed integrally.
[0034]
A lead wire 51 that electrically connects the sensor board 34 and the power board 41 is connected from the sensor board 34 to a connector 52 provided below the power board 41. In addition, a lead wire 53 that supplies drive power to the stator 25 is connected to a connector 54 provided below the power board 41. Further, lead wires 55, 56, and 57 to which U-phase, V-phase, and W-phase drive signals of the motor 21 are supplied are connected to the power board 41.
[0035]
In the following description, a portion near the support leg 36 of the power board 41 and used for interconnecting the radiator plate 31 and the power board 41 is referred to as a first fixing portion 45, and is near the support leg 37 of the power board 41. A part used for interconnecting the heat sink 31 and the power board 41 is referred to as a second fixing part 46.
[0036]
One end of a needle pin 47 is fixed at a position corresponding to the first fixing portion 45 of the heat sink 31 by means such as press fitting. The tip of the needle pin 47 penetrates the power board 41 and protrudes to the opposite side, and a push nut 48 is attached to the tip of the needle pin 47.
[0037]
As shown in FIG. 4, the push nut 48 is formed in a substantially disk shape from a metal material having elasticity, and has an insertion hole 49 having an inner diameter D2 smaller than the diameter D1 of the needle pin 47. In addition, cuts are formed at a plurality of positions along the circumferential direction in an annular portion between the virtual circle having a diameter D3 larger than the diameter D1 of the needle pin 47 and the insertion hole 49, and a plurality of elastic pieces are formed. 50 are formed. When the needle pin 47 is pushed into the insertion hole 49 by pushing and expanding the elastic piece 50, the needle pin 47 and the push nut 48 are fixed to each other by the spring force of the elastic piece 50. Since the spring force of the push nut 48 also acts in the axial direction of the needle pin 47, the power board 41 is elastically urged toward the heat radiating plate 31 and the electronic circuit element 38 contacts the heat radiating plate 31. maintain.
[0038]
On the other hand, in the second fixing portion 46, as described above, the outer peripheral edge of the power board 41 is engaged with the step 43 near the tip of the support leg 37, and the gap between the step 43 and the engagement claw 44 is formed. Then, the power board 41 is sandwiched and fixed. A fan 50 is fixed to one end of the rotating shaft 30.
[0039]
When such a motor 21 is driven, cooling air is generated by the rotation of the fan 50, and flows around the housing 24, between the fins 33 of the heat sink 31, and around the power board 41.
[0040]
In the motor 21 having such a configuration, since the electronic circuit element 38 is in contact with the heat sink 31, heat from the electronic circuit element 31 is effectively transmitted to the heat sink 31, and heat of the heat sink 31 is reduced. The fins 33 are effectively cooled. Thereby, the temperature rise of the motor 21 can be effectively suppressed. Further, since the fins 33 of the heat radiating plate 31 extend toward the housing 24, the heat generated in the motor 21 is effectively transmitted to the heat radiating plate 31 through the fins 33. Can be effectively suppressed.
[0041]
In the motor 21, even if the heat generated from the electronic circuit element 38 and the housing 24 increases, the leads 55, 56, and 57 are connected to the lower side of the power board 41. Is prevented from being deteriorated or burnt under the influence of the heat.
[0042]
In the motor 21, the radiator plate 31 and the power board 41 are combined with the needle pin 47 and the push nut 48, and the step 43 of the support leg 37 of the radiator plate 31, the engaging claw 44 and the outer peripheral portion of the power board 41 are provided. And are fixed to each other by the engagement relationship with.
[0043]
Therefore, since the necessity of screwing the heat sink 31 and the power board 41 to each other is eliminated, the number of parts and the number of working steps required for mutual fixing of the both are reduced. In addition, since the diameter of the needle pin 47 can be significantly smaller than that of a screw or a connecting boss formed on the heat radiating plate 31, an empty space to be considered in circuit wiring of the power board 41 can be reduced, and design is free. The degree can be improved. Further, in the mutual fixing of the two, a situation such as breakage of the power board 41 due to excessive tightening of the screw, which is assumed in the case of the screw tightening operation, is prevented.
[0044]
(Second embodiment)
FIG. 5 is a side view similar to FIG. 2 of a motor 21a according to a second embodiment of the present invention.
[0045]
Hereinafter, this embodiment will be described with reference to FIG.
[0046]
This embodiment is similar to the first embodiment, and corresponding parts are denoted by the same reference numerals. The feature of this embodiment is that the heat radiating plate 31 in the first embodiment is provided over the entire circumference so as to surround the housing 24, and the fins 33 are also formed over the entire circumference of the housing 24.
[0047]
In such an embodiment, it is apparent that the same operation and effect as those described in the first embodiment can be realized, and the heat can be more effectively transmitted from the housing 24 to the heat dissipation plate 31. The operation and effect described in the first embodiment can be further improved.
[0048]
(Third embodiment)
FIG. 6 is a front view showing a part of the motor 21b according to the third embodiment of the present invention.
[0049]
This embodiment is similar to the first embodiment, and corresponding parts are denoted by the same reference numerals. In this embodiment, for the sake of simplicity, the description is limited to the heat radiating plate 31 and the power board 41, but it is assumed that other configurations are the same as those in the first embodiment.
[0050]
The feature of the present embodiment is that when connecting the heat radiating plate 31 and the power board 41 to each other, the support legs 36 and the stepped portions, which are the components for interconnecting the first fixing portions 45 described in the first embodiment. The configuration for connection using the needle 42, the needle pin 47, and the push nut 48 is used for both the first fixing part 45 and the second fixing part 46.
[0051]
(Fourth embodiment)
FIG. 7 is a front view showing a part of a motor 21c according to a fourth embodiment of the present invention.
[0052]
This embodiment is similar to the third embodiment, and corresponding parts are denoted by the same reference numerals. In this embodiment, for the sake of simplicity, the description is limited to the heat radiating plate 31 and the power board 41, but it is assumed that other configurations are the same as those in the first embodiment.
[0053]
This embodiment is characterized in that a spring washer 58 or a flat spring is used between the push nut 48 and the power board 41 described in the first embodiment when connecting the heat sink 31 and the power board 41 to each other. That was done.
[0054]
Therefore, in this embodiment, in addition to the operation and effect described in the third embodiment, when it is necessary to particularly cool the electronic circuit element 38, the power board 41 is resiliently moved toward the heat sink 31 by using the spring washer 58. Pressing. Thereby, the electronic circuit element 38 can be brought into contact with the heat radiating plate 31 with an appropriate pressure, and the heat radiating action can be more effectively realized.
[0055]
(Modification)
In each of the above embodiments, a configuration example shown in FIG. 8 can be adopted as a modified example of the mechanism used to connect the heat sink 31 and the power board 41.
[0056]
FIG. 8 is a front view showing a part of the motor 21d of this configuration example.
[0057]
This modification is similar to the first embodiment, and corresponding parts are denoted by the same reference numerals. In this modification, for simplicity of description, the description will be limited to the heat radiating plate 31 and the power board 41, but it is assumed that other configurations are the same as those of the first embodiment.
[0058]
This modification includes a case where the heat sink 31 and the power board 41 are connected to each other with screws 59.
[0059]
In addition, an engaging member 60 formed integrally with the heat radiating plate 31 and protruding toward the power board 41 may be used. The engagement member 60 has elasticity so that it can contract and expand in the radial direction, and a fitting groove 61 into which the power board 41 fits is formed on the outer periphery.
[0060]
In such a modified example, the same operation and effect as the operation and effect of each of the above embodiments can be realized.
[0061]
【The invention's effect】
According to the first aspect of the present invention, since the electronic circuit component is in contact with or close to the radiator plate, heat from the electronic circuit component is effectively transmitted to the radiator plate, and heat of the radiator plate is effectively transmitted by the fins. Is cooled. Thereby, the temperature rise of the motor can be effectively suppressed. In addition, since the fins of the heat sink extend toward the housing, the heat generated in the motor is effectively transmitted to the heat sink through the fins, and in this respect, it is also possible to effectively suppress the temperature rise of the motor. Can be.
[0062]
In the case of the motor according to the second aspect, since the heat radiating plate is arranged over the entire circumference of the housing, heat is more effectively transmitted from the housing to the heat radiating plate. It can be further improved.
[0063]
In the case of the motor according to the third aspect, even if the heat generated from the electronic circuit components and the housing increases, the lead wire is connected to the lower side of the wiring board, so that the operation and effect according to the first aspect can be realized. In addition, it is possible to prevent the lead wire from being deteriorated or damaged by the influence of the heat.
[0064]
In the case of the motor according to the fourth and fifth aspects, since the necessity of screwing the heat sink and the wiring board to each other is eliminated, the number of parts and the number of working steps required for mutual fixing of both are reduced.
[0065]
In the case of the motor described in claim 6, these functions and effects can be realized for a DC brushless motor.
[Brief description of the drawings]
FIG. 1 is a front view showing a partial cross section of a motor 21 according to a first embodiment of the present invention.
FIG. 2 is a right side view of FIG.
FIG. 3 is a bottom view of the motor 21.
FIG. 4 is a view showing a push nut.
FIG. 5 is a side view similar to FIG. 2 of a motor 21a according to a second embodiment of the present invention.
FIG. 6 is a front view showing a part of a motor 21b according to a third embodiment of the present invention.
FIG. 7 is a front view showing a part of a motor 21c according to a fourth embodiment of the present invention.
FIG. 8 is a front view showing a part of a motor 21d according to a modification of the present invention.
FIG. 9 is a partial sectional view of a prior art brushless motor.
[Explanation of symbols]
21, 21a, 21b, 21c, 21d Motor 24 Housing 25 Stator 26 Bracket 29 Rotor 30 Rotating shaft 38 Electronic circuit element 31 Heat sink 32 Screw 33 Fin 36, 37 Support leg 41 Power board 42, 43 Step 44 Engage Claws 45, 46 Fixing part 47 Needle pin 48 Push nut 49 Insertion hole 50 Fan 50 Elastic pieces 51, 53, 55, 56, 57 Lead wire 58 Spring washer 59 Screw 60 Engaging member 61 Fitting groove D2 Inner diameter D3 Diameter

Claims (6)

A metal housing with a stator and a rotor,
A fan outside the housing and coaxially connected to the rotor and driven to rotate;
A radiator plate arranged at a distance below the housing,
A plurality of fins extending from one surface of the heat sink toward the housing;
A wiring board arranged at an interval on the other surface side of the heat sink,
An electronic circuit component mounted on the wiring board and in contact with or in proximity to the heat sink,
A motor having: The motor according to claim 1, wherein the heat radiating plate is arranged all around the housing. The motor according to claim 1, wherein a lead wire is connected to a lower side of the wiring board. The motor according to any one of claims 1 to 3, wherein the heat sink and the wiring board are fixed by a needle pin and a push nut. The motor according to claim 4, wherein a spring washer or a spring is disposed between the heat sink and the wiring board. The motor according to any one of claims 1 to 5, wherein the motor is a brushless DC motor.

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