JP6852271B2 - motor - Google Patents

Description

The present invention relates to a motor.

Conventionally, a motor has a control unit on which a rotor, a stator, a circuit board, and the like are mounted. When electric power is supplied to the stator from an external power source or the like via the control unit, the rotor can rotate relative to the stator.

Various elements, wiring, and the like are arranged on the circuit board. When a current flows from an external power source or the like to the circuit board, the elements and wiring on the circuit board generate heat. Such heat generation may not only destroy the element itself but also deform the circuit board and the like. Therefore, it is necessary to take measures such as dissipating the heat generated from the element or the like to the outside of the motor or the like.

As one of the heat dissipation measures as described above, for example, in Patent Document 1, a heat sink made of a metal material or the like is arranged around the control unit. Specifically, a first frame member covering the upper part is attached to the upper part of the cylindrical motor case, and a second frame member covering the lower part is attached to the lower part of the motor case. The heat sink is arranged on the upper part of the first frame member and is fixed to the first frame with screws. A power substrate is arranged on the upper surface of the heat sink, a control board is arranged on the lower surface, and a semiconductor module is arranged on the side surface. As a result, the heat generated by the electronic components of the power board and the control board and the semiconductor module is conducted to the heat sink and the first frame member. Therefore, their own temperature rise is suppressed, and their damage and destruction are suppressed or prevented.

Japanese Unexamined Patent Publication No. 2014-225998

However, in Patent Document 1, the first frame member and the second frame member are further added to the upper surface and the lower surface of the motor case. Therefore, the axial dimension of the rotation axis of the rotor increases. In addition, the number of motor parts increases. Therefore, the number of assembly steps and the manufacturing cost increase.

In view of the above situation, it is an object of the present invention to provide a motor having a heat dissipation structure that can be easily assembled by reducing the dimensions in the axial direction.

In order to achieve the above object, an exemplary motor of the present invention includes a rotor having a rotating shaft extending in the vertical direction, a stator facing the rotor, a housing holding the stator, and a heat sink attached to the housing. And a circuit board on which electronic components are mounted and arranged on a heat sink. Electronic components include heat generating elements. The housing has a tubular tubular portion and a lid portion that covers an end surface of the tubular portion. The heat sink is in contact with the upper surface of the lid and is directly attached to the lid using a fixing member. The heat generating element is in contact with the heat sink via the heat conductive member. The lid portion has a protruding portion that protrudes toward the heat sink in the axial direction, and an annular portion that is continuously formed at the outer peripheral end of the protruding portion. The heat sink has a storage portion formed by a recess facing the lid portion on the lower surface. At least a part of the protrusion is arranged in the storage part. The annular portion is in contact with the heat sink. A hole for fixing the fixing portion is formed on the bottom surface of the storage portion. At least some electronic components except the heat generating element are mounted on the surface of the circuit board opposite to the heat sink. The axial dimension of the electronic component mounted on the surface of the circuit board opposite to the heat sink is larger than the axial dimension of the heat generating element.

According to the exemplary motor of the present invention, it is possible to provide a motor having a heat dissipation structure that can be easily assembled by reducing the dimensions in the axial direction.

FIG. 1 is a schematic vertical sectional view showing a configuration example of a motor according to the first embodiment of the present invention. FIG. 2 is a schematic vertical sectional view showing a configuration example between the heat sink and the circuit board according to the first embodiment of the present invention. FIG. 3 is a schematic vertical sectional view showing a configuration example between the heat sink and the circuit board according to the modified example of the first embodiment of the present invention. FIG. 4 is a schematic vertical sectional view showing a configuration example between the heat sink and the circuit board according to the second embodiment of the present invention.

An exemplary embodiment of the present invention will be described below with reference to the drawings. In the present specification, the direction in which the rotation axis of the rotor 101 (see the shaft 101a in FIG. 1 described later) extends is simply referred to as "axial direction". Further, in the axial direction, the direction from the shaft 101a toward the heat sink 2 is simply referred to as "upward" in the axial direction, and the direction from the heat sink 2 toward the shaft 101a is simply referred to as "downward" in the axial direction. Further, the radial direction centered on the shaft 101a is simply referred to as "diameter direction". Further, on the surface of each component, a surface facing upward in the axial direction is referred to as an "upper surface", a surface facing downward in the axial direction is referred to as a "lower surface", and a surface facing downward in the axial direction is referred to as a "side surface".

<1. First Embodiment>
<1-1. Outline configuration of motor>
First, the motor 100 according to the first embodiment of the present invention will be described. FIG. 1 is a schematic vertical sectional view showing a configuration example of the motor 100 according to the first embodiment of the present invention. FIG. 1 shows a cross section when the motor 100 is cut on a cutting surface including the rotation axis of the rotor 101. The motor 100 in FIG. 1 is a motor mounted on a vehicle or the like.

The motor 100 includes a rotor 101, an annular stator 102, a housing 1, a heat sink 2, a circuit board 3, a bearing 5, a cover 104, and a connector 105.

The rotor 101 has a shaft 101a and a plurality of magnets 101b. The shaft 101a is a rotating shaft extending in the vertical direction in the axial direction. The stator 102 is an armature of the motor 100 and is arranged so as to face the rotor 101. The housing 1 is a metal housing that houses the rotor 101, the stator 102, and the like, and holds the stator 102 and the bearing 5.

The heat sink 2 is formed of a material having good thermal conductivity such as aluminum and copper, and is attached to the housing 1 using screws 6. The circuit board 3 mounts the control circuit of the motor 100 and is arranged on the heat sink 2. The control circuit is electrically connected to the stator 102 via a through hole provided in the heat sink 2 and the housing 1 (the lid portion 1b described later).

Further, a position detection sensor 103 is provided on the lower surface of the circuit board 3. The position detection sensor 103 has its center located on the rotation axis of the shaft 101a and detects the rotation angle of the rotor 101.

The bearing 5 is a bearing that rotatably supports the shaft 101a. The bearing 5 is composed of, for example, a ball bearing or a sleeve bearing. The cover 104 is a member that protects the circuit board 3, is provided on the heat sink 2 and the circuit board 3, and covers the upper surfaces thereof.

The connector 105 is an external connection terminal, and electrically connects the circuit board 3 with an external power supply (not shown) and other external devices (not shown) via wiring 105a. When power is supplied from an external power source to the stator 102 via the connector 105 and the circuit board 3, the rotor 101 becomes rotatable relative to the stator 102.

<1-2. Housing configuration>
The housing 1 has a tubular tubular portion 1a, a lid portion 1b, and a lower lid 1c. The lid portion 1b is formed of the same member as the tubular portion 1a and covers the upper end surface of the tubular portion 1a. The lower lid 1c covers the open end surface on the lower side of the tubular portion 1a, and is attached to the lower end of the tubular portion 1a by a fixing means (not shown). A central opening 10a is formed in the central portion of the lower lid 1c. A bearing 5 is attached to the central opening 10a, and a shaft 101a is inserted through the central opening 10a. The cylinder portion 1a and the lid portion 1b may be separate members, not limited to the example of FIG.

The lid portion 1b has a protruding portion 11, an annular portion 12, a protruding wall portion 13, and an insertion hole 14. The protruding portion 11 projects in the axial direction from the inner peripheral end of the annular portion 12. That is, the annular portion 12 is continuously formed at the outer peripheral end of the protruding portion 11. The inside of the protruding portion 11 is recessed upward, and a central opening 10b through which the shaft 101a is inserted is formed in the central portion of the bottom surface thereof.

A protrusion 13 is formed around the central opening 10b along the central opening 10b. The protruding wall portion 13 extends downward in the axial direction from the bottom surface of the protruding portion 11. A bearing 5 is attached to the inside of the protruding wall portion 13. That is, the protruding wall portion 13 is a holding portion arranged in the protruding portion 11 to hold the bearing 5. The bearing 5 attached to the central opening 10b of the lid 1b rotatably supports the shaft 101a together with the bearing 5 attached to the central opening 10a of the lower lid 1c.

A plurality of insertion holes 14 are formed on the outside of the protruding wall portion 13. A screw 6 is inserted into these insertion holes 14. In FIG. 1, a screw 6 is used as a fixing member for attaching and fixing the heat sink 2 to the lid portion 1b, but the present invention is not limited to this example, and the fixing member may be another member such as a rivet.

Further, on the upper surface and the lower surface of the lid portion 1b (particularly, the outer surface and the inner surface of the protruding portion 11), the periphery of the insertion hole 14 is polished, and the surface roughness around the insertion hole 14 is other than that of the housing 1. It is made smaller than the surface roughness of the portion (for example, the outer peripheral surface of the tubular portion 1a). By doing so, the screw 6 and the heat sink 2 can be easily brought into close contact with the lid portion 1b. Therefore, the heat sink 2 can be firmly attached and fixed by the lid portion 1b using the screws 6.

<1-3. Heat sink configuration>
As shown in FIG. 1, the heat sink 2 is in contact with the upper surface of the lid portion 1b and is attached to the lid portion 1b using screws 6. In the motor 100, since no other member such as a frame is interposed between the housing 1 and the heat sink 2, the axial dimension can be made smaller than that of a motor having a conventional structure in which a frame is interposed, and assembly can be easily performed. It can be carried out. Further, the number of parts can be reduced, and the manufacturing cost of the motor 100 can also be reduced.

The heat sink 2 has a storage portion 21, an insertion opening 22, and a screw hole 23. The storage portion 21 is a recess on the lower surface of the heat sink 2 facing the lid portion 1b as shown in FIG. In this embodiment, the heat sink 2 is a single member. Not limited to this example, the heat sink 2 may be composed of a plurality of members.

An insertion opening 22 and a screw hole 23 are formed on the bottom surface of the storage portion 21. The insertion opening 22 penetrates the heat sink 2 in the axial direction and opens toward the position detection sensor 103 arranged on the lower surface of the circuit board 3. In the insertion opening 22, the upper end portion of the shaft 101a is arranged downward in the axial direction with respect to the position detection sensor 103.

The screw hole 23 is provided on the radial outer side of the insertion opening 22. When the heat sink 2 is attached to the lid portion 1b, the screw 6 is fixed to the screw hole 23 via the insertion hole 14.

At least a part of the lid portion 1b is arranged in the storage portion 21, and in particular, the entire protruding portion 11 fits into the storage portion 21. It should be noted that the present invention is not limited to the example of FIG. 1, and at least a part of the protruding portion 11 may be arranged in the storage portion 21. In this way, the size of the motor 100 in the axial direction can be further reduced.

The protruding portion 11 of the lid portion 1b is in contact with the bottom surface of the storage portion 21. Therefore, the protruding portion 11 of the housing 1 can be directly applied to the heat sink 2 to position the heat sink 2 with respect to the housing 1 in the axial direction.

Further, around the storage portion 21, the annular portion 12 is in contact with the lower surface of the heat sink 2. Therefore, the heat sink 2 can be directly applied to the annular portion 12 of the housing 1 to more reliably position the heat sink 2 with respect to the housing 1 in the axial direction.

On the lower surface of the heat sink 2 (particularly the bottom surface of the storage portion 21), at least a part of the portion in contact with the lid portion 1b (particularly the region in contact with the protruding portion 11) is subjected to polishing or the like, and the surface roughness thereof is the heat sink 2. It is made smaller than the surface roughness of the surface (for example, the side surface) other than the lower surface of the. By doing so, when the heat sink 2 is screwed to the lid portion 1b, the adhesion between the heat sink 2 and the lid portion 1b is enhanced, and in particular, the protruding portion 11 is easily brought into close contact with the bottom surface of the storage portion 21. Therefore, the heat sink 2 can be more firmly attached to the flange portion 1d by using the screw 6. Further, since the heat sink 2 facilitates heat transfer to the housing 1, the heat dissipation of the heat sink 2 can be improved.

Although the insertion opening 22 is formed on the bottom surface of the storage portion 21 in FIG. 1, the present invention is not limited to this example, and a recess may be formed instead of the insertion opening 22. When the recess is formed, the upper end of the shaft 101a is arranged in the recess, and the position detection sensor 103 is provided on the bottom surface of the recess. The position detection sensor 103 is connected to the circuit board 3 through, for example, a through hole (not shown) provided in the heat sink 2.

Further, although the storage portion 21 is formed as a concave portion in FIG. 1, the storage portion 21 is not limited to this example, and may be formed as a through hole that opens toward the lid portion 1b. However, in this case, the screw hole 23 is provided on the lower surface of the heat sink 2 on the radial outer side of the storage portion 21, and the insertion hole 14 is provided in the annular portion 12 of the lid portion 1b.

<1-4. Circuit board configuration>
The circuit board 3 is a substrate using a resin material such as epoxy. The circuit board 3 is attached to the upper surface of the heat sink 2 using, for example, screws or rivets (not shown). FIG. 2 is a schematic vertical sectional view showing a configuration example between the heat sink 2 and the circuit board 3 according to the first embodiment of the present invention. FIG. 2 shows a vertical cross section when the heat sink 2 and the circuit board 3 are cut on a plane parallel to the axial direction.

The electronic component 4 is mounted on the circuit board 3. The electronic component 4 includes a heat generating element 4a having a relatively large amount of heat generation and a low heat generating element 4b having a relatively small amount of heat generation. The heat generating element 4a is, for example, a switching element such as a FET (Field Emission Transistor). The low heat generating element 4b is, for example, a capacitor or the like.

As shown in FIG. 2, the heat generating element 4a is mounted on the surface of the circuit board 3 facing the heat sink 2 (that is, the lower surface of the circuit board 3) and is arranged between the heat sink 2 and the circuit board 3. Thermal paste 7 is applied to the lower surface of the heat generating element 4a (for example, the surface facing the heat sink 2). In FIG. 2, the heat generating element 4a comes into contact with the heat sink 2 via the thermal paste 7. By transferring heat from the heat generating element 4a to the heat sink 2 via the thermal paste 7, the heat generated by the heat generating element 4a can be easily transferred to the heat sink 2.

At least a part of the electronic components 4 (for example, the low heat generating element 4b) other than the heat generating element 4a are mounted on the surface of the circuit board 3 opposite to the heat sink 2 (the upper surface of the circuit board 3). In this way, the electronic component 4 whose axial dimension is larger than that of the heat generating element 4a is not arranged between the heat sink 2 and the circuit board 3. Therefore, the heat sink 2 and the heat generating element 4a can be easily brought into contact with each other via the thermal paste 7. Therefore, the heat generated by the heat generating element 4a mounted on the circuit board 3 can be easily transferred to the heat sink 2, and the temperature rise of the heat generating element 4a can be suppressed.

Not limited to the example of FIG. 2, a heat radiating agent other than the heat radiating grease 7, another heat conductive member, or the like may be provided between the lower surface of the heat generating element 4a and the heat sink 2. The heat radiating agent, the heat conductive member, etc. may be provided in place of the heat radiating grease 7 or may be provided together with the heat radiating grease 7 as long as they are excellent in heat conductivity, electrical insulation, and low thermal expansion. Good.

<1-5. Modification example of the first embodiment>
Next, a modification of the motor 100 of the first embodiment will be described. FIG. 3 is a schematic vertical sectional view showing a configuration example between the heat sink 2 and the circuit board 3 according to the modified example of the first embodiment. FIG. 3 shows a vertical cross section when the heat sink 2 and the circuit board 3 are cut on a plane parallel to the axial direction.

As shown in FIG. 3, an accommodating recess 2a is formed on the upper surface of the heat sink 2 at a position corresponding to the heat generating element 4a mounted on the lower surface of the circuit board 3. The heat generating element 4a is housed in the housing recess 2a. The lower surface of the heat generating element 4a is in contact with the bottom surface of the accommodating recess 2a via the thermal paste 7. When an electronic component 4 other than the heat generating element 4a (for example, a low heat generating element 4b) is mounted on the lower surface of the circuit board 3, even if at least a part of the electronic component 4 is accommodated in the accommodating recess 2a in the same manner. Good. Further, when the dimensions of the electronic component 4 mounted on the lower surface of the circuit board 3 in the axial direction are different, the depth of the accommodating recess 2a may be set according to the dimensions of the corresponding electronic component 4. In this way, the circuit board 3 can be arranged close to the heat sink 2. Therefore, the axial dimension of the motor can be further shortened.

<2. Second Embodiment>
<2-1. Circuit board configuration>
Next, the motor 100 according to the second embodiment of the present invention will be described. FIG. 4 is a schematic vertical sectional view showing a configuration example between the heat sink 2 and the circuit board 3 according to the second embodiment of the present invention. FIG. 4 shows a vertical cross section when the heat sink 2 and the circuit board 3 are cut on a plane parallel to the axial direction. The basic configuration of this embodiment is the same as that of the first embodiment described above. Therefore, the components common to the first embodiment may be given the same reference numerals or the same names as before, and the description thereof may be omitted.

The circuit board 3 is a substrate having a so-called copper inlay structure. A metal member 3a is arranged in the through hole 3b penetrating the circuit board 3. In the present embodiment, copper is used for the metal member 3a, but other metal materials may be used. The metal member 3a penetrates the circuit board 3 as shown in FIG.

The electronic component 4 (particularly the heat generating element 4a) is mounted on the surface of the circuit board 3 opposite to the heat sink 2 (that is, the upper surface of the circuit board 3). The heat generating element 4a is provided on the upper surface of the metal member 3a. The thermal paste 7 is applied to at least the lower surface of the metal member 3a of the lower surface of the circuit board 3. Therefore, the heat generating element 4a comes into contact with the heat sink 2 via the heat conductive member including the metal member 3a and the thermal paste 7.

In this way, the heat generated by the heat generating element 4a mounted on the surface of the circuit board 3 opposite to the heat sink 2 is transmitted to the heat sink 2 via the metal member 3a and the heat conductive member including the thermal paste 7 to dissipate heat. Can be done. Further, for example, the electronic component 4 whose axial dimension is larger than that of the heat generating element 4a is not arranged between the heat sink 2 and the circuit board 3. As a result, the heat sink 2 and the heat generating element 4a can be easily brought into contact with each other via the metal member 3a and the thermal paste 7. Therefore, the heat generated by the heat generating element 4a mounted on the circuit board 3 can be easily transferred to the heat sink 2, and the temperature rise of the heat generating element 4a can be suppressed.

<3. Others>
The embodiment of the present invention has been described above. The scope of the present invention is not limited to the above-described embodiment. The present invention can be implemented with various modifications without departing from the gist of the invention. In addition, the above-described embodiments can be arbitrarily combined as appropriate.

For example, although the first and second embodiments described above show the case where the present invention is applied to an in-vehicle motor, the present invention may be applied to a motor other than the in-vehicle motor.

The present invention can be used, for example, in an in-vehicle motor, and can also be used in a motor for other purposes.

1 ... Housing, 1a ... Cylinder part, 1b ... Lid part, 1c ... Lower lid, 10a, 10b ... Central opening, 11 ... Protruding part, 12 ... Circular part, 13 ... Protruding wall part, 14 ... Insertion hole, 2 ... Heat sink, 2a ... Storage recess, 21 ... Storage part, 22 ... Insertion opening, 23 ... Screw hole, 3 ... Circuit board, 3a ... Metal member, 3b ... Through hole, 4 ... Electronic component, 4a ... Heat generation element, 4b ... Low heat generation element, 5 ... Bearing, 6. ... Screw, 7 ... Thermal paste, 100 ... Motor, 101 ... Rotor, 101a ... Shaft, 101b ... Magnet, 102 ... Stator, 103 ... Position detection sensor, 104 ... cover, 105 ... connector, 105a ... wiring

Claims (8)

A rotor having a rotating shaft extending in the vertical direction, a stator facing the rotor, a housing for holding the stator, a heat sink attached to the housing, and a circuit board on which electronic components are mounted and arranged on the heat sink. And with
The electronic component includes a heat generating element, and the electronic component includes a heat generating element.
The housing has a tubular tubular portion and a lid portion that covers an end surface of the tubular portion.
The heat sink is in contact with the upper surface of the lid and is directly attached to the lid using a fixing member.
The heat generating element comes into contact with the heat sink via a heat conductive member, and the heat generating element comes into contact with the heat sink.
The lid portion has a protruding portion that protrudes toward the heat sink in the axial direction, and an annular annular portion that is continuously formed at the outer peripheral end of the protruding portion.
The heat sink has a storage portion formed by a recess facing the lid portion on the lower surface thereof.
At least a part of the protrusion is arranged in the storage portion.
The annular portion is in contact with the heat sink and is in contact with the heat sink.
A hole for fixing the fixing portion is formed on the bottom surface of the storage portion.
At least some of the electronic components except the heat generating element are mounted on the surface of the circuit board opposite to the heat sink.
A motor characterized in that the axial dimension of the electronic component mounted on the surface of the circuit board opposite to the heat sink is larger than the axial dimension of the heat generating element. The motor according to claim 1 , wherein the protruding portion is in contact with the bottom surface of the recess. A bearing that supports the rotating shaft and a holding portion that holds the bearing are further provided.
The motor according to claim 1 or 2 , wherein the holding portion is arranged in the protruding portion. The motor according to any one of claims 1 to 3 , wherein the fixing member is a screw or a rivet. The lid portion has an insertion hole, and the fixing member is inserted through the insertion hole.
The motor according to claim 4 , wherein the surface roughness around the insertion hole in the lid portion is smaller than the surface roughness of the outer peripheral surface of the tubular portion. The motor according to any one of claims 1 to 5 , wherein the heat generating element is arranged between the heat sink and the circuit board. The motor according to any one of claims 1 to 6 , wherein the heat conductive member contains thermal paste. The motor according to any one of claims 1 to 7 , wherein the heat generating element is a switching element.

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