JP2021100302A - motor - Google Patents

Abstract

To provide a motor structured to suppress the leakage of electromagnetic noise generated from an electronic component to the outside while suppressing enlargement in size.SOLUTION: A motor comprises a rotor 20, a stator, a first reference member 11 in which the rotor and the stator are accommodated and which includes an opening at one side in an axial direction, and a circuit board 61 which is provided at the opening side of the first reference member 11 separately from the first reference member 11 in the axial direction. An electronic component and pattern layers to be connected to the electronic component are provided on a surface of the circuit board 61 at the first reference member 11 side. One of the pattern layers in the circuit board 61 is a metal layer 61b which is spread along a board surface of the circuit board 61. A plurality of metallic column parts 80 which extend in the axial direction between the circuit board 61 and the first reference member 11 and connect the circuit board 61 with the first reference member 11 are further provided. The plurality of column parts 80 are disposed side by side while being spaced apart from each other around the electronic component when seen in the axial direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to a motor.

Motors equipped with electronic components such as inverters are known. For example, Patent Document 1 describes a high-voltage circuit for driving a motor including an inverter as an electronic component.

JP-A-2010-112261

In a motor as described above, electromagnetic noise is generated from electronic components. Therefore, for example, by surrounding the electronic component with a metal case, it is possible to prevent electromagnetic noise generated from the electronic component from leaking to the outside of the motor. However, in this case, the metal case tends to be relatively large, and the entire motor may be large.

In view of the above circumstances, one object of the present invention is to provide a motor having a structure capable of suppressing leakage of electromagnetic noise generated from electronic components to the outside while suppressing an increase in size.

One embodiment of the motor of the present invention accommodates a rotor having a shaft centered on a central axis, a stator facing the rotor in the radial direction through a gap, and the rotor and the stator on one side in the axial direction. A first reference member having an opening in the first reference member, and a circuit board provided on the opening side of the first reference member so as to be separated from the first reference member in the axial direction. An electronic component and a pattern layer connected to the electronic component are provided on the surface of the circuit board on the side of the first reference member. One of the pattern layers in the circuit board is a metal layer extending along the plate surface of the circuit board. The motor further includes a plurality of metal columns extending axially between the circuit board and the first reference member to connect the circuit board and the first reference member. Each of the plurality of pillars is arranged at a distance from each other so as to surround the electronic component when viewed along the axial direction.

According to one aspect of the present invention, it is possible to suppress the leakage of electromagnetic noise generated from electronic components to the outside while suppressing the increase in size of the motor.

FIG. 1 is a cross-sectional view showing a motor of the first embodiment. FIG. 2 is a cross-sectional view showing a part of the motor of the first embodiment. FIG. 3 is a view of a part of the motor control device of the first embodiment as viewed from above. FIG. 4 is a cross-sectional view showing a part of the motor of the second embodiment.

The Z-axis direction appropriately shown in each figure is a vertical direction in which the positive side is the "upper side" and the negative side is the "lower side". The central axis J appropriately shown in each figure is a virtual line that is parallel to the Z-axis direction and extends in the vertical direction. In the following description, the axial direction of the central axis J, that is, the direction parallel to the vertical direction is simply referred to as "axial direction", and the radial direction centered on the central axis J is simply referred to as "diametrical direction". The circumferential direction centered on is simply called the "circumferential direction".

The vertical direction, the upper side, and the lower side are names for simply explaining the arrangement relationship of each part, and the actual arrangement relationship, etc. is an arrangement relationship, etc. other than the arrangement relationship, etc. indicated by these names. You may.

<First Embodiment>
As shown in FIG. 1, the motor 10 of the present embodiment includes a housing 11, a rotor 20, a stator 30, a bearing holder 40, bearings 51 and 52, and a control device 60. The housing 11 houses the rotor 20, the stator 30, the bearing holder 40, and the bearings 51 and 52. The housing 11 has a tubular shape that opens upward. More specifically, the housing 11 has a cylindrical shape centered on the central axis J. In this embodiment, the housing 11 is made of metal.

The rotor 20 has a shaft 21 and a rotor body 22. The shaft 21 is a columnar shape extending in the axial direction about the central axis J. The rotor body 22 is fixed to the outer peripheral surface of the shaft 21. Although not shown, the rotor body 22 has a rotor core and a rotor magnet.

The stator 30 faces the rotor 20 in the radial direction through a gap. In this embodiment, the stator 30 is located radially outside the rotor 20. The stator 30 includes a stator core 31, an insulator 34, and a plurality of coils 35. The stator core 31 has an annular core back 32 centered on the central axis J, and a plurality of teeth 33 extending radially inward from the core back 32. The plurality of coils 35 are attached to each of the plurality of teeth 33 via the insulator 34.

The bearing holder 40 is fixed to the inner peripheral surface of the housing 11. The bearing holder 40 holds the bearing 52.

The control device 60 is a device that controls the drive of the motor 10. The control device 60 is located above the housing 11. The control device 60 is exposed to the outside of the housing 11. The control device 60 is supported from below by a plurality of pillars 80 extending from the housing 11 and fixed to the housing 11. As shown in FIGS. 1 and 2, the control device 60 includes a circuit board 61 and an electronic component 70. The motor 10 includes a circuit board 61, an electronic component 70, and a plurality of pillars 80.

The circuit board 61 is a multilayer board having a plurality of pattern layers laminated in the axial direction. In the present embodiment, the circuit board 61 is a two-layer board having a pattern layer. The circuit board 61 is in contact with the housing 11. The circuit board 61 is located above the stator 30. The circuit board 61 covers the upper opening of the housing 11. In the present embodiment, the circuit board 61 has a disk shape centered on the central axis J.

As shown in FIG. 2, the circuit board 61 has a substrate main body 61a, a metal layer 61b, and a wiring pattern 61c. The substrate body 61a is a disk-shaped insulating member. The metal layer 61b is a metal layer that extends along the plate surface of the circuit board 61. The metal layer 61b is one of a plurality of pattern layers in the circuit board 61. In the present embodiment, the metal layer 61b is a pattern layer located on the uppermost side of the plurality of pattern layers on the circuit board 61. The metal layer 61b is a so-called solid pattern. In this embodiment, the metal constituting the metal layer 61b is a non-magnetic material. The metal constituting the metal layer 61b is, for example, copper.

The wiring pattern 61c is a metal pattern that is electrically connected to the electronic component 70. The wiring pattern 61c is one of the pattern layers in the circuit board 61. That is, the circuit board 61 has a metal layer 61b and a wiring pattern 61c as two pattern layers. In the present embodiment, the wiring pattern 61c is the lowermost pattern layer among the plurality of pattern layers on the circuit board 61. The wiring pattern 61c is provided on the lower surface of the substrate body 61a.

The connector 91 is fixed to the lower surface of the circuit board 61. The metal wiring 91a is electrically connected to the wiring pattern 61c. As shown in FIG. 3, for example, three cables 92a, 92b, and 92c extend radially outward from the connector 91. The cable 92a is a power supply line that supplies electric power to the electronic component 70. The cable 92b is a signal line for signal transmission with the electronic component 70. The cable 92c is a GND line to and from the electronic component 70. The cables 92a, 92b, and 92c extend from the connector 91 radially outward of the circuit board 61 via the axial direction between the housing 11 and the circuit board 61. Although not shown, the cables 92a, 92b, and 92c are electrically connected to the electronic component 70 via the wiring pattern 61c.

As shown in FIG. 2, the circuit board 61 is supported from below by a pillar portion 80 that penetrates the circuit board 61 in the axial direction and is fixed to the housing 11. The circuit board 61 is electrically connected to the housing 11. In this embodiment, the pillar portion 80 and the metal layer 61b are soldered. As a result, the circuit board 61 is electrically connected to the housing 11 via the metal layer 61b and the pillar portion 80. In this embodiment, the housing 11 is a first reference member having a first reference potential. That is, the circuit board 61 is electrically connected to the housing 11 which is the first reference member having the first reference potential and is grounded.

The electronic component 70 is attached to the housing 11 side of the plate surface of the circuit board 61. Therefore, the electromagnetic noise emitted upward from the electronic component 70 can be blocked by the circuit board 61. In this way, since a part of the electromagnetic noise generated from the electronic component 70 can be blocked by using the circuit board 61, it is possible to suppress the electromagnetic noise from leaking to the outside of the motor 10 without covering the control device 60 with the metal case. .. As a result, the motor 10 can be miniaturized because the metal case is not provided, which leads to cost reduction. Therefore, it is possible to suppress the electromagnetic noise generated from the electronic component 70 from leaking to the outside of the motor 10 while suppressing the increase in size of the motor 10.

In this embodiment, a plurality of electronic components 70 are provided. The electronic component 70 includes an inverter 71, a rotation sensor 72, a capacitor 73, a converter 74, and a microcomputer 75.

At least two electronic components 70 of the plurality of electronic components 70 are electrically connected to form an electronic circuit 70a. In the present embodiment, the electronic circuit 70a is configured by electrically connecting an inverter 71, a rotation sensor 72, a capacitor 73, a converter 74, and a microcomputer 75. In this embodiment, each electronic component 70 constituting the electronic circuit 70a is electrically connected via a wiring pattern 61c. In the present embodiment, in the electronic circuit 70a, the grounding portion 63 included in the wiring pattern 61c penetrates the substrate body 61a in the axial direction and is connected to the metal layer 61b. As a result, the electronic circuit 70a is electrically connected to the housing 11 which is the first reference member via the metal layer 61b and the pillar portion 80, and is grounded. As described above, according to the present embodiment, the electronic circuit 70a can be grounded by connecting to the metal layer 61b provided on the circuit board 61. Therefore, it is easy to ground the electronic circuit 70a.

In the present embodiment, the electronic circuit 70a is connected to the metal layer 61b only by the grounding portion 63, and the electronic circuit 70a is electrically connected to the metal layer only at one place for grounding. Therefore, a closed circuit passing through the metal layer, the housing 11, and the electronic circuit 70a is not formed. As a result, even if an eddy current is generated in the metal layer or the housing 11 and a potential difference is generated in the metal layer or the housing 11, the current does not flow to the electronic circuit 70a through the metal layer and the housing 11. Will be done. Therefore, it is possible to suppress the flow of unnecessary current through the electronic circuit 70a, and it is possible to prevent the electronic circuit 70a from malfunctioning.

In the present specification, "there is only one location of the metal layer to which the electronic circuit is electrically connected for grounding" means that the electronic circuit is electrically connected to only one location of the metal layer. All that is required is that the plurality of portions of the electronic circuit that are electrically connected to the metal layer are all connected to one location on the metal layer. Further, the "one place" of the metal layer includes a part of the metal layer which is electrically regarded as one place. Specifically, if the impedance is relatively small and the potential difference is unlikely to occur, it can be electrically regarded as one location.

The inverter 71 has a plurality of transistors. The inverter 71 is electrically connected to the coil 35 of the stator 30. Power is supplied to the coil 35 from the inverter 71. In this embodiment, the circuit board 61 is located above the stator 30. Therefore, the coil 35 can be easily electrically connected to the inverter 71.

The rotation sensor 72 detects the rotation of the rotor 20. The rotation sensor 72 is a magnetic sensor that detects the rotation of the rotor 20 by detecting the magnetic field of a sensor magnet (not shown) attached to the upper end of the shaft 21. The rotation sensor 72 is, for example, a magnetoresistive element. As described above, the metal constituting the metal layer 61b is a non-magnetic material. The rotation sensor 72 may be a Hall element such as a Hall IC.

A part of the housing 11 of the plurality of pillars 80 extends in the axial direction and is located between the circuit board 61 and the housing 11. In the present embodiment, the pillar portion 80 connects the opening of the housing 11 and the surface of the metal layer 61b on the upper side of the circuit board 61.

As shown in FIG. 3, in the present embodiment, for example, eight pillar portions 80 are provided. The plurality of pillar portions 80 are arranged along the circumferential direction at intervals from each other. In the present embodiment, the pillar portion 80 is located radially outside the electronic component 70. As a result, the plurality of pillar portions 80 are arranged so as to surround the electronic component 70 with a distance from each other when viewed along the axial direction.

In this way, each of the plurality of pillars 80 surrounding the electronic component 70 when viewed along the axial direction is electrically connected by soldering to the metal layer 61b. Therefore, at least a part of the electromagnetic noise emitted from the electronic component 70 to the outside in the radial direction can be blocked by the pillar portion 80. Thereby, even if the metal case is not provided, the electromagnetic noise generated from the electronic component 70 can be further blocked by utilizing the pillar portion 80 located between the circuit board 61 and the circuit board 61 in the axial direction. Therefore, it is possible to further suppress the leakage of electromagnetic noise generated from the electronic component 70 to the outside of the motor 10 while suppressing the increase in size of the motor 10.

In the present embodiment, when the wavelength of the highest frequency of the electromagnetic noise generated from the electronic component 70 is λ, the distance L between the adjacent pillars 80 when viewed along the axial direction is 0. The relationship <L <λ / 4 is satisfied. The distance L is a straight line distance between the pillars 80 when viewed along the axial direction. In FIG. 3, the distance L is shown as the distance between the pillar portions 80 adjacent to each other in the circumferential direction. Further, in the present embodiment, the axial distance between the metal layer 61b and the housing 11 which is the first reference member satisfies the relationship of 0 <H <λ / 4. As shown in FIG. 2, the distance H is the axial distance between the metal layer 61b and the housing 11.

When the distance between the parts that block the electromagnetic noise is smaller than 1/4 of the wavelength of the electromagnetic noise, the electromagnetic noise cannot pass between the parts that block the electromagnetic noise. Therefore, when the relationship of 0 <L <λ / 4 and 0 <H <λ / 4 is satisfied, the electromagnetic noise of all frequencies generated from the electronic component 70 passes between the column portions 80 in the circumferential direction. Can not do it. As a result, the electromagnetic noise emitted from the electronic component 70 to the outside in the radial direction can be more preferably blocked by the plurality of pillars 80.

As an example, when the clock frequency of the microcomputer 75 is 100 MHz, the highest frequency of the electromagnetic noise generated from the microcomputer 75 is, for example, about 2 GHz, which is 20 times the clock frequency. Therefore, the wavelength λ of the highest frequency among the frequencies of the electromagnetic noise generated from the microcomputer 75 is 0.15 m. Therefore, if the distance L and the distance H are smaller than 0.0375 m, the electromagnetic noise emitted from the microcomputer 75 to the outside in the radial direction by the plurality of pillars 80 can be blocked.

As described above, according to the present embodiment, the metal layer 61b and the housing 11 which is the first reference member can block the electromagnetic noise emitted from the electronic component 70 on both sides in the axial direction, and the metal layer 61b and the pillar portion can be blocked. The 80 can block the electromagnetic noise emitted from the electronic component 70 to the outside in the radial direction. Therefore, the circuit board 61 and the plurality of pillars 80 can be used to more preferably block the electromagnetic noise generated from the electronic component 70. As a result, it is possible to more preferably suppress the leakage of electromagnetic noise to the outside of the motor 10 while suppressing the increase in size of the motor 10. In the present embodiment, the axial distance H between the metal layer 61b and the housing 11 which is the first reference member is smaller than, for example, the distance L.

Further, according to the present embodiment, since the pillar portions 80 are arranged side by side at intervals, the cables 92a, 92b, 92c and the like described above can be pulled out from between the pillar portions 80. Therefore, the wiring of the electronic component 70 can be facilitated as compared with the case where the metal case is provided. Further, the air outside the motor 10 can be taken in from between the pillar portions 80. Therefore, the heat dissipation of the control device 60 can be improved.

In the present embodiment, the pillar portion 80 is provided so as to surround the wiring region C in the circuit board 61 when viewed along the axial direction. The wiring area C is an area on the lower surface of the circuit board 61 where the wiring pattern 61c is provided. As a result, the electromagnetic noise generated from the wiring pattern 61c can be blocked by the pillar portion 80. Therefore, it is possible to further suppress the leakage of electromagnetic noise to the outside of the motor 10. In the example of FIG. 3, the wiring region C is a circular region centered on the central axis J. The pillar portion 80 is located on the wiring region C.

Although not shown, the diameter of the metal layer 61b may be smaller than the diameter of the housing 11 which is the first reference member. When the wavelength of the highest frequency of the electromagnetic noise generated from the electronic component 70 is λ, the radial distance R between the outer peripheral edge of the metal layer 61b and the inner diameter of the housing 11 which is the first reference member is The relationship of 0 <R <λ / 4 is satisfied. At this time, it is even better to satisfy the relations of 0 <L <λ / 4 and 0 <H <λ / 4.

When the distance between the parts that block the electromagnetic noise is smaller than 1/4 of the wavelength of the electromagnetic noise, the electromagnetic noise cannot pass between the parts that block the electromagnetic noise. Therefore, when the relationships of 0 <R <λ / 4, 0 <L <λ / 4 and 0 <H <λ / 4 are satisfied, the electromagnetic noise of all frequencies generated from the electronic component 70 is the metal layer 61b. Cannot pass between the outer peripheral edge of the housing 11 and the inner diameter of the housing 11 which is the first reference member. Thereby, the electromagnetic noise emitted from the electronic component 70 to the outside in the radial direction can be more preferably blocked.

<Second Embodiment>
As shown in FIG. 4, in the motor 110 of the present embodiment, the circuit board 161 is fixed to the housing 11 by soldering. The pillar portion 180 comes into contact with the metal layer 161b through the through hole 161d provided in the circuit board 161. As a result, the metal layer 161b is electrically connected to the housing 11 and is grounded.

The connector 196 is fixed to the lower surface of the circuit board 161. A metal wiring 196a is provided inside the connector 196. The metal wiring 196a is electrically connected to the grounding portion 163 of the wiring pattern 161c. Cable 197 extends from connector 196. The cable 197 is drawn radially outward from the connector 196.

The cable 197 is electrically connected to the housing DH of a device (not shown) on which the motor 110 is mounted. As a result, the electronic circuit 170a is electrically connected to the housing DH via the metal wiring 196a and the cable 197 and is grounded. The housing DH is a second reference member having a second reference potential. The housing 11 which is the first reference member and the housing DH which is the second reference member are insulated from each other. Therefore, no current flows between the metal layer 161b and the electronic circuit 170a, and it is possible to further suppress the flow of unnecessary current through the electronic circuit 170a. Therefore, it is possible to further suppress the malfunction of the electronic circuit 170a.

The present invention is not limited to the above-described embodiment, and other configurations may be adopted. The number of electronic components is not particularly limited and may be one. The electronic circuit may be composed of only some of the plurality of electronic components. A plurality of electronic circuits may be provided. The grounding method of the electronic circuit is not particularly limited. For example, screws may be used to electrically connect the metal layer to the housing. In this case, for example, the screw penetrates the circuit board in the axial direction, but insulates the wiring pattern from the screw. The connector 196 described in the second embodiment may be provided on the metal layer 161b side on the upper side of the circuit board 161.

The circuit board may be a multilayer board having three or more layers as long as it is a multilayer board. In this case, the metal layer in the circuit board may be a layer sandwiched by an insulating layer in the axial direction. The direction in which the circuit board is arranged with respect to the stator may be a direction other than the axial direction, and may be, for example, a radial direction.

The pillar portion is not particularly limited. The pillar portion may be separate from the housing. The pillar portion may be, for example, a spacer member. The distance L between the pillars may be larger than λ / 4. The pillar portion may have a metal portion. The material of the housing is not particularly limited. The housing may be made of resin. In this case, the first reference member may be a housing on which the motor is mounted.

The use of the motor of the above-described embodiment is not particularly limited. The motor of the above-described embodiment is mounted on, for example, a vacuum cleaner or the like. The configurations described in the present specification can be appropriately combined within a range that does not contradict each other.

10, 110 ... Motor, 11 ... Housing (first reference member), 20 ... Rotor, 21 ... Shaft, 30 ... Stator, 61, 161 ... Circuit board, 61b, 161b ... Metal layer, 70 ... Electronic components, 70a, 170a ... Electronic circuit, 71 ... Inverter, 72 ... Rotation sensor, 73 ... Capacitor, 74 ... Converter, 75 ... Microcomputer, 80, 180 ... Pillar, DH ... Housing (second reference member) H, L, R ... Distance, J ... central axis, λ ... wavelength

Claims (10)

It ’s a motor,
A rotor with a shaft centered on the central axis, and
A stator facing the rotor in the radial direction through a gap,
A first reference member that houses the rotor and the stator and has an opening on one side in the axial direction.
A circuit board provided on the opening side of the first reference member at a distance from the first reference member in the axial direction.
With
An electronic component and a pattern layer connected to the electronic component are provided on the surface of the circuit board on the side of the first reference member.
One of the pattern layers in the circuit board is a metal layer extending along the plate surface of the circuit board.
The motor further comprises a plurality of metal columns extending axially between the circuit board and the first reference member to connect the circuit board and the first reference member.
A motor in which each of the plurality of pillars is arranged at a distance from each other so as to surround the electronic component when viewed along the axial direction. The motor according to claim 1, wherein the metal layer is a pattern layer located on one side of the plurality of pattern layers in the circuit board in the axial direction. When the wavelength of the highest frequency among the frequencies of electromagnetic noise generated from the electronic component is λ,
The motor according to claim 1 or 2, wherein the linear distance L between adjacent pillars when viewed along the axial direction satisfies the relationship of 0 <L <λ / 4. When the wavelength of the highest frequency among the frequencies of electromagnetic noise generated from the electronic component is λ,
The motor according to any one of claims 1 to 3, wherein the axial distance H between the circuit board and the first reference member satisfies the relationship of 0 <H <λ / 4. When the wavelength of the highest frequency among the frequencies of electromagnetic noise generated from the electronic component is λ,
The method according to any one of claims 1 to 4, wherein the radial distance R between the outer peripheral edge of the metal layer and the inner diameter of the first reference member satisfies the relationship of 0 <R <λ / 4. Motor. The motor according to any one of claims 1 to 5, wherein the first reference member is a housing of the motor. A plurality of the electronic components are provided,
At least two of the plurality of electronic components are electrically connected to form an electronic circuit.
The motor according to any one of claims 1 to 6, wherein the electronic circuit is electrically connected to the first reference member and grounded. The motor according to claim 7, wherein the first reference member is electrically connected to the electronic circuit for grounding at only one place. A plurality of the electronic components are provided,
At least two of the plurality of electronic components are electrically connected to form an electronic circuit.
The electronic circuit is electrically connected to a second reference member having a second reference potential and is grounded.
The motor according to any one of claims 1 to 8, wherein the first reference member and the second reference member are insulated from each other. The motor according to claim 9, wherein the second reference member is a housing of a device on which the motor is mounted.

Images