JP2016174105A - Dynamo-electric means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contribute to reconciliation of radiation noise suppression and cost reduction.SOLUTION: In a motor unit 10, a circuit element 30 becoming a generation source of noise is housed in a metallic case 12 constituted by fastening a plurality of metallic case components 14, 16. In the metallic case 12, a thermal deformation part 32 deformed at the seam 18 of the case components 14, 16 are interconnecting the case components 14, 16 electrically. Consequently, a current generated in the clearance of the seam 18 is reduced by a magnetic field generated from the circuit element 30. As a result, leakage of noise from the seam 18 caused by the current is suppressed, thus contributing to suppression of the radiation noise. When compared with a configuration where a plurality of case components are brought into close contact by means of a large number of fastening members, assembly manhours can be reduced thus contributing to cost reduction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric device in which a circuit element serving as a noise generation source is housed in a metal case.

  In the motor unit described in Patent Document 1 below, a plurality of circuit elements for controlling the driving of the electric motor are attached to a circuit board housed in a case composed of an upper case and a lower case. These circuit elements include switching elements and the like. In addition, Patent Documents 2 and 3 below describe similar techniques.

JP 2014-54017 A JP 2005-192364 A JP 2000-23408 A

  In the motor unit as described above, noise due to a magnetic field generated from a switching element or the like may adversely affect the peripheral device. For this reason, in order to suppress the radiation of noise, the case for housing the circuit board may be made of metal. Such a metal case is configured by, for example, a plurality of metal case parts being fastened by a plurality of fastening members (screws, bolts, etc.). Noise may leak. Such leakage of low frequency noise can be suppressed by bringing the case parts into close contact with each other by a large number of fastening members. However, the increase in the number of assembling steps has caused the manufacturing cost to increase.

  In view of the above facts, an object of the present invention is to obtain an electric device that contributes to both suppression of radiation noise and cost reduction.

  The electric device according to the present invention includes a circuit element that is a noise generation source and a plurality of metal case parts that are fastened together, and a metal case that houses the circuit element therein, and the adjacent case parts And a deformed portion that is deformed at a joint portion between them and electrically connects the adjacent case parts.

  According to the electric device having the above-described configuration, the circuit element serving as the noise generation source is housed in the metal case formed by fastening a plurality of metal case parts to each other. Moreover, in this metal case, the deformation | transformation part deform | transformed in the seam part of adjacent case components has electrically connected the said adjacent case components. In other words, since this deformed portion adds an electrical connection point (hereinafter referred to as a contact) to the joint portion between adjacent case parts, the current generated in the joint portion due to the magnetic field generated from the circuit element is reduced. Is done. As a result, noise leakage from the joint portion due to the current is suppressed, which contributes to suppression of radiation noise. In addition, as compared with the configuration in which a plurality of case parts are brought into close contact with each other by a large number of fastening members, the number of assembling steps can be reduced, which contributes to cost reduction.

  In addition to the above configuration, in the electric device of the present invention, the deformation portion may be a heat deformation portion that is deformed by welding heat when the adjacent case components are welded to each other, or the adjacent case components. Is a plastically deformed portion that is plastically deformed when the concave and convex portions are fitted in the concave and convex portions.

  According to the electric device having the above configuration, the adjacent case components are electrically connected at the joint portion by the thermal deformation portion or the plastic deformation portion. Since these thermal deformation parts or plastic deformation parts are formed when the case parts are welded or concavo-convexly fitted, an increase in the number of assembling steps can be effectively suppressed or prevented.

  Furthermore, in the electric device of the present invention, in addition to the above configuration, the deforming portion is a conductive seal member that is compressed and deformed between the adjacent case components.

  According to the electric device having the above-described configuration, the conductive seal member that is compressed and deformed between the adjacent case components electrically connects the adjacent case components at the joint portion. Thereby, suppression of radiation noise and the waterproof seal | sticker of the said seam part can be made compatible.

  Furthermore, in the electric device according to the present invention, in addition to the above configuration, the deforming portion is provided at at least three locations in the joint portion.

  According to the electric device having the above-described configuration, at the joint portion between adjacent case components, at least three deformed portions electrically connect the adjacent case components. As described above, by providing the deformed portions at least at three locations in the joint portion, it is possible to effectively suppress noise leakage from the joint portion.

  In addition to the above-described configuration, the electric device of the present invention includes, in the metal case, a fastening portion in which the adjacent case components are fastened by a fastening member, and a non-fastening portion in which the deformation portion is provided. Are alternately provided at three or more locations.

  According to the electric device having the above configuration, the metal case is provided with three or more fastening portions and non-fastening portions by the fastening member alternately, and each of the plurality of non-fastening portions is provided with a deforming portion. Yes. Thereby, the electrical connection location of adjacent case components can be increased efficiently, setting the number of fastening members small.

  In addition to the above-described configuration, the electric device according to the present invention accommodates in the metal case a drive circuit configured to include the circuit element and an electric motor whose drive is controlled by the drive circuit. Has been.

  According to the electric device configured as described above, the drive circuit that controls the drive of the electric motor includes the circuit element that is a source of noise generation. Housed in a case. Thereby, the motor unit which contributes to coexistence with suppression of radiation noise and cost reduction can be provided.

1 is a schematic side view showing a motor unit as an electric device according to a first embodiment of the present invention. It is a schematic plan view showing the motor unit. It is an expanded sectional view which expands and shows the cut surface along the F3-F3 line of FIG. It is a schematic plan view which shows the motor unit as an electric apparatus which concerns on 2nd Embodiment of this invention. It is an expanded sectional view which expands and shows the cut surface along the F5-F5 line of FIG. It is a schematic plan view which shows the motor unit as an electric apparatus which concerns on 3rd Embodiment of this invention. It is an expanded sectional view which expands and shows the cut surface along the F7-F7 line | wire of FIG. It is a perspective view which shows the result of having analyzed by computer simulation the radiation noise of the motor unit by which the contact is not added to the joint part of case parts. It is the top view which looked at the simulation result shown by FIG. 8A from the upper side of the motor unit. It is a perspective view which shows the result of having analyzed by computer simulation the radiation noise of the motor unit by which the contact was added to three places of the joint part of case parts. It is the top view which looked at the simulation result shown by FIG. 9A from the upper side of the motor unit. It is a perspective view which shows the result of having analyzed by computer simulation the radiation noise of the motor unit in which the contact was added to five places of the joint parts of case parts. It is the top view which looked at the simulation result shown by FIG. 10A from the upper side of the motor unit. It is a diagram which shows the relationship between the presence or absence of the addition of the contact in the joint part of case parts, and magnetic field intensity.

(First embodiment)
Hereinafter, the motor unit 10 as the electric device according to the first embodiment of the present invention will be described with reference to FIGS. The motor unit 10 is a so-called circuit-integrated motor in which a motor and an electronic circuit are accommodated in an integrated case, and includes a metal case 12 as shown in FIGS. 1 and 2. The metal case 12 is configured by fastening (connecting) a first case component 14 and a second case component 16 as a plurality of case components. Both the first case component 14 and the second case component 16 are made of metal.

  The first case component 14 is formed in a bottomed cylindrical shape. The second case component 16 includes a bottomed cylindrical main body portion 16A having a smaller diameter and a shorter axial dimension than the first case component 14, and an end portion on the opening side of the main body portion 16A (the lower end portion in FIG. 1). Part) and a flange part 16B extending outward in the radial direction of the main body part 16A, and is formed in a substantially hat shape. The second case component 16 has a flange portion 16 </ b> B superimposed on an opening end portion (the upper end portion in FIG. 1) of the first case component 14, and is coaxially disposed with respect to the first case component 14. Has been.

  The second case component 16 is fastened and fixed to the first case component 14 with a plurality of (here, four) screws 20 as a plurality of fastening members. The plurality of screws 20 penetrate through the flange portion 16B of the second case component 16 and are screwed into a female screw portion (not shown) formed at the end of the first case component 14 on the opening side. Thereby, the first case part 14 and the second case part 16 which are mutually adjacent case parts are integrated by fastening, and the opening of the first case part 14 is closed by the second case part 16. Yes.

  The plurality of screws 20 are arranged at equal intervals in the circumferential direction of the metal case 12. That is, in the metal case 12, the first case part 14 and the second case part 16 (that is, the case parts adjacent to each other) are fastened by the screw 20 and the non-fastened part is not fastened by the screw 20. The fastening portions 22 are alternately provided at three or more locations (here, four locations). In each fastening portion 21, the first case component 14 and the second case component 16 are mechanically coupled by screw fastening, are in close contact with each other, and are electrically connected with low resistance. In addition, although the setting location of the fastening part 21 and the non-fastening part 22 is not restricted to four places and can be changed suitably, it is preferable to set to three or more places. Further, the fastening member is not limited to the screw 20, and other types of fastening members such as bolts may be used.

  As shown in FIG. 1, an electric motor 24 and a circuit board 28 including a drive circuit 26 that controls driving of the electric motor 24 are accommodated inside the metal case 12 having the above-described configuration. The drive circuit 26 includes a plurality of circuit elements 30 that are noise generation sources. These circuit elements 30 include, for example, FETs that are switching elements.

  Here, in this embodiment, the plurality of non-fastening portions 22 in the metal case 12 are each provided with a heat deformation portion 32 (see FIG. 3) as a deformation portion. The plurality of (four here) thermal deformation portions 32 are welded (spot welded here) to the first case component 14 at a plurality of locations (four locations here) of the flange portion 16B of the second case component 16. Is deformed by welding heat and is constituted by a part of the first case part 14 and the second case part 16.

  That is, the plurality of thermally deformable portions 32 are formed by the first case component 14 and the second case component 16 being partially melted and deformed at the joint portion 18 between the first case component 14 and the second case component 16 and then solidified. . The plurality of thermal deformation portions 32 are arranged at equal intervals in the circumferential direction of the metal case 12, and the plurality of thermal deformation portions 32 and the plurality of screws 20 are alternately arranged in the circumferential direction of the metal case 12. Are evenly spaced. In addition, the member which attached | subjected the code | symbol 34 in FIG. 3 is an electrode of a spot welding gun.

  Each thermal deformation portion 32 integrally couples the first case component 14 and the second case component 16 by welding and is electrically connected with low resistance. In addition, since the first case component 14 and the second case component 16 are welded at the plurality of thermal deformation portions 32, the first case component 14 and the second case component 16 are in close contact with each other at the plurality of non-fastening portions 22. The area of the bent portion is enlarged, and the gap of the joint portion 18 is reduced. In addition, in this embodiment, it was set as the structure by which the heat deformation part 32 was each formed in the some non-fastening part 22, However, Not only this but the heat deformation part 32 is formed only in some of the some non-fastening parts 22. It may be configured as described above.

  Next, the operation and effect of the first embodiment will be described.

  In the motor unit 10 configured as described above, an electric motor 24 and a drive circuit 26 are housed in a metal case 12 configured by fastening a first case component 14 and a second case component 16 to each other. The drive circuit 26 includes a plurality of circuit elements 30 including FETs that are switching elements, and generates a magnetic field from the FETs when energized. As a result, an eddy current that cancels the magnetic field is generated on the inner surface of the metal case 12 where the magnetic field collides. This eddy current causes low frequency noise (magnetic field noise).

  Here, in the present embodiment, in the metal case 12 described above, a plurality of thermal deformation portions 32 are formed at the joint portion 18 between the first case component 14 and the second case component 16, and these thermal deformation portions. 32, the first case part 14 and the second case part 16 are electrically connected. As a result, it is possible to suppress a part of the eddy current from concentrating on the surface of the joint portion 18 in the gap of the joint portion 18, thereby suppressing leakage of low frequency noise from the joint portion 18 due to the eddy current. Is done.

  That is, when the plurality of thermal deformation portions 32 are not present in the joint portion 18 between the first case component 14 and the second case component 16, a part of the eddy current generated in the metal case 12 is not fastened. In the gap of the joint portion 18 at 22, the surface is concentrated on the surface of the joint portion 18. A part of the eddy current becomes stronger as it is closer to the circuit element 30 that is a source of noise. Then, in accordance with the right-handed screw law, a magnetic field is newly generated in a direction penetrating the eddy current generated on the surface of the joint portion 18, and low-frequency noise generated by the magnetic field leaks from the joint portion 18.

  On the other hand, in the present embodiment, the first case component 14 and the second case component 16 are electrically connected at a fastening portion 21 by a plurality of screws 18 with low resistance, The fastening portion 22 is also electrically connected with a low resistance by the thermal deformation portion 32. Thereby, in the non-fastening part 22, the flow of the eddy current concentrated in the gap of the joint 20 is inhibited. As a result, noise leakage from the joint portion 18 is suppressed, which contributes to suppression of radiation noise. In addition, in the present embodiment, the number of assembling steps can be reduced as compared with the configuration in which the first case component 14 and the second case component 16 are brought into close contact with each other by fastening with a large number of fastening members. Contribute.

  In the present embodiment, since the first case component 14 and the second case component 16 are welded at the plurality of thermal deformation portions 32, the first case component 14 and the second case at the plurality of non-fastening portions 22. The area of the part (the part electrically connected with low resistance) in close contact with the component 16 is enlarged. Moreover, in the plurality of thermal deformation portions 32, the first case component 14 and the second case component 16 are physically deformed by welding heat, and the metal material of the first case component 14 and the second case component 16 is changed. Distortion has occurred. Thereby, since the flow of the eddy current generated on the surface of the joint portion 18 can be effectively inhibited, it contributes effectively to the suppression of radiation noise.

  Furthermore, in this embodiment, since the several heat deformation part 32 can be formed by carrying out the spot welding of the 1st case component 14 and the 2nd case component 16 effectively, the increase in an assembly man-hour is effective. Can be suppressed.

  Furthermore, in the present embodiment, the joint portion 18 between the first case component 14 and the second case component 16 is provided with the thermal deformation portions 32 at three or more locations (here, four locations). It is possible to effectively suppress noise leakage from the.

  Further, in the present embodiment, the metal case 12 includes three fastening parts 21 in which the case parts 14 and 16 are fastened by the screws 20 and three non-fastening parts 22 in which the thermal deformation parts 32 are provided. There are more than four places (here, four places). Thereby, the electrical connection location of adjacent case components 14 and 16 can be increased efficiently, setting the number of screws 20 small.

  As described above, according to this embodiment, it is possible to provide the motor unit 10 that contributes to both suppression of radiation noise and cost reduction.

  Next, another embodiment of the present invention will be described. In addition, about the structure and effect | action similar to the said 1st Embodiment, the same code | symbol as the said 1st Embodiment is provided, and the description is abbreviate | omitted.

(Second Embodiment)
FIG. 4 shows a motor unit 40 as an electric device according to the second embodiment of the present invention in a plan view corresponding to FIG. FIG. 5 shows an enlarged cross-sectional view of the cut surface along the line F5-F5 in FIG. The motor unit 40 has basically the same configuration as the motor unit 10 according to the first embodiment. However, instead of the plurality of thermal deformation portions 32 according to the first embodiment, a plurality of deformation portions are provided. A plurality (four in this case) of plastic deformation portions 42 are provided. The plurality of plastic deformation portions 42 are respectively provided in the plurality of non-fastening portions 22, similarly to the plurality of heat deformation portions 32.

  Each plastic deformation portion 42 is a portion in which the first case component 14 and the second case component 16 are partially plastically deformed by the concave and convex fitting of the concave portion 44 and the convex portion 46 in the joint portion 18. Specifically, when the convex portion 46 protruding from the second case component 16 that is one case component is press-fitted into the concave portion 44 formed in the first case component 14 that is the other case component. In addition, the plastic deformation portions 42 are formed by plastic deformation of the contact portions of the concave portions 44 and the convex portions 46.

  Each plastic deformation portion 42 integrally couples the first case component 14 and the second case component 16 and is electrically connected with a low resistance. Further, in the plurality of non-fastening portions 22, the area of the portion where the first case component 14 and the second case component 16 are in close contact with each other is increased due to the fitting (press-fit) of the concave portion 44 and the convex portion 46, The gap of the joint portion 18 is reduced. The configuration other than the above is the same as that of the first embodiment.

  This embodiment also contributes to both reduction of radiation noise and cost reduction as in the first embodiment. In addition, since it is only necessary to form the concave portion 44 and the convex portion 46 in the first case component 14 and the second case component 16, it is possible to prevent the assembly man-hour from increasing.

(Third embodiment)
FIG. 6 shows a motor unit 50 as an electric device according to the second embodiment of the present invention in a plan view corresponding to FIG. FIG. 7 shows an enlarged cross-sectional view of a cut surface along the line F7-F7 in FIG. The motor unit 50 has basically the same configuration as the motor unit 10 according to the first embodiment, but has conductivity instead of the plurality of thermal deformation portions 32 according to the first embodiment. A metal gasket (seal member: deformed portion) 52 is provided.

  The metal gasket 52 is compressed and deformed between the first case component 14 and the second case component 16. Specifically, an annular groove portion 54 is formed concentrically with the first case component 14 on the end surface of the first case component 14 on the second case component 16 side, and a metal gasket 52 is formed in the groove portion 54. Is arranged. The metal gasket 52 is manufactured to have a circular cross section. When the first case component 14 and the second case component 16 are fastened by the screws 20, the first case component 14 and the second case component are used. The cross section is deformed into an ellipse by being subjected to compressive deformation (plastic deformation) with respect to 16. The first case component 14 and the second case component 16 are electrically connected with low resistance via the metal gasket 52. Further, the gap between the joint portions 18 is waterproof-sealed by the metal gasket 52. The configuration other than the above is the same as that of the first embodiment.

  This embodiment also contributes to both reduction of radiation noise and cost reduction as in the first embodiment. In addition, in this embodiment, since the joint portion 18 is waterproof-sealed by the metal gasket 52, it is possible to achieve both suppression of radiation noise and waterproof sealing of the joint portion 18.

(Analysis result by computer simulation)
8A and 8B show a perspective view and a plan view of the results of analyzing the radiated noise of the motor unit 60 in which a contact (electrical connection point) is not added to the joint between the case parts by computer simulation. Is shown. 9A and 9B show a perspective view and a plan view showing a result of analyzing the radiation noise of the motor unit 62 in which contacts are added at three locations of the joint portions of the case parts by computer simulation. ing. Further, in FIGS. 10A and 10B, the results of analysis by computer simulation of the radiation noise of the motor unit 64 in which contacts are added at the five joints of the case parts are shown in a perspective view and a plan view. ing. FIG. 11 is a diagram showing the relationship between the presence / absence of contact addition at the joint between the case components and the magnetic field strength.

  In the motor units 60, 62, 64 (simulation model), the metal first case component 66 and the metal second case component 68 are fastened by a plurality of screws 72, and the metal case 74 is configured. Further, an electric motor (not shown) and a drive circuit (not shown) for controlling the driving of the electric motor are accommodated. This drive circuit includes circuit elements (such as FETs) that are sources of noise. In this respect, the motor units 60, 62, and 64 have a common configuration.

  However, the motor unit 60 is not provided with electrical contacts at the joint portion 70 between the first case component 66 and the second case component 68, but the joint portion 70 of the motor unit 62 is provided at three locations. Contact points (see the crosses in FIG. 9A) are set, and contact points (see the crosses in FIG. 10A) are set at five locations on the joint portion 70 of the motor unit 64.

  For these motor units 60, 62, and 64, radiation noise was analyzed by computer simulation. In FIG. 8A to FIG. 10B, the dots are darker as the noise increases. As shown in FIGS. 8A to 10B, it was confirmed that as the number of contacts increases in the joint portion 70, noise emission (leakage) from the joint portion 70 decreases. Further, as shown in FIG. 11, it was confirmed that the magnetic field strength decreased as the number of contacts increased. Note that an arrow Z in FIG. 11 indicates the measurement direction of the magnetic field strength. From the above, it was confirmed that the application of the present invention suppresses the emission of magnetic field noise and improves the shielding performance of the metal case.

  In each of the above embodiments, the case where there are two case parts (the first case part 14 and the second case part 16) constituting the metal case has been described. However, the present invention is not limited to this, and the metal case is used. The number of case parts constituting 12 may be three or more.

  In each of the above embodiments, the case where the present invention is applied to a motor unit that is a circuit-integrated motor has been described. However, the present invention is not limited to this, and the present invention can be applied to other types of electric devices. Can be applied.

  In addition, the present invention can be implemented with various modifications without departing from the scope of the invention. It goes without saying that the scope of rights of the present invention is not limited to the above embodiments.

  DESCRIPTION OF SYMBOLS 10 ... Motor unit (electric device), 12 ... Metal case, 14 ... 1st case component, 16 ... 2nd case component, 18 ... Seam part, 20 ... Screw ( Fastening member), 21 ... Fastening part, 22 ... Non-fastening part, 24 ... Electric motor, 26 ... Drive circuit, 30 ... Circuit element, 32 ... Thermal deformation part (deformation part) , 40... Motor unit (electric device), 40... Motor unit (electric device), 42... Plastic deformation portion (deformation portion), 44. ... Motor unit (electric device), 52 ... Metal gasket (seal member: deformation part), 60 ... Motor unit (electric device), 62 ... Motor unit (electric device), 64 ... Motor unit (electric device), 66... First case part, 68 - second case part, 69 ... joint portion, 70 ... screw (fastening member), 72 ... metal casing

Claims (6)

A circuit element that is a source of noise;
A plurality of metal case parts are configured to be fastened together, and a metal case containing the circuit element therein,
Deformed at the joint between adjacent case parts, and a deformed part electrically connecting the adjacent case parts;
Electric device with   The deformation part is a heat deformation part deformed by welding heat when the adjacent case parts are welded together, or plastic deformation when the adjacent case parts are unevenly fitted in the concave and convex parts. The electric device according to claim 1, which is a plastically deformed portion.   The electric device according to claim 1, wherein the deformable portion is a conductive seal member that is compressed and deformed between the adjacent case components.   The electric device according to claim 2, wherein the deformable portion is provided in at least three places in the joint portion.   5. The metal case is provided with three or more fastening portions alternately provided with fastening portions where the adjacent case parts are fastened by fastening members and non-fastening portions provided with the deformation portions. The electric device described. The drive case comprised including the said circuit element and the electric motor by which a drive is controlled by the said drive circuit are accommodated in the said metal case. The electric device described in 1.