JP2018073863A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an electronic device including a configuration capable of suppressing movement of powder generated in the enclosure.SOLUTION: In an electronic device (100) including a circuit board (105), and an enclosure (101) constituted of two supports (101a, 101b), the circuit board includes recesses (216A, 216B, 316C, 316D, 216E, 316F, 216a, 216b, 216e) formed at positions in contact with the outer boundary of the circuit board, and protrusions (206a, 206b, 206c, 206d, 206e, 226a, 226b, 226e) formed at positions in contact with the outer boundary and adjacent to the recesses. The two supports are arranged so that at least one of which abuts on the bottom face of the recess, and fix the circuit board in the enclosure while clamping in the thickness direction at the abutment positions (110a, 110b, 110c, 110d, 110e, 110f).SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electronic device, and more particularly to an electronic device including a circuit board that is sandwiched and fixed inside a housing.

  In general, in an electronic control unit (ECU: Electronic Control Unit) that performs vehicle control, a circuit board on which a control circuit is mounted is fixed in a housing. For example, two supports (base and cover) that constitute the housing Thus, the circuit board can be fixed in the housing by mechanically sandwiching a predetermined portion of the circuit board.

  In such a case, for example, the base and the cover constituting the casing can sandwich a material portion (for example, a resin material) constituting the circuit board. The base and the cover are made of metal and are sandwiched so as to be in contact with the ground pattern formed on the circuit board, whereby the ground pattern and the housing can be electrically connected together with fixing the circuit board.

  When the circuit board is sandwiched in such a manner, the metal that is normally used as the two supports constituting the housing and the resin material that is usually used in the circuit board have greatly different linear expansion coefficients. Due to a change in environmental temperature, there may be a relative positional shift between the base and cover and the circuit board, and both may slide.

  Further, if the portion sandwiched between the base and the cover is, for example, a material portion of a circuit board, the material portion is worn by sliding as described above, and the resin material (insulator) constituting the circuit board is worn. Powder may be generated. If such powder enters a circuit contact (for example, a contact between terminals in a connector or the like) to cause a contact failure, there is a possibility of causing an abnormality in the circuit operation.

  Further, even when the portion sandwiched between the base and the cover is a ground pattern portion formed on the circuit board, the metal thin film constituting the ground pattern may be worn by the sliding to generate metal powder. If such a metal powder may cause a short circuit between the wirings of the control circuit, for example, it may cause a serious abnormality in the circuit operation.

JP 2014-197816 A

  From such a background, even when the circuit board is sandwiched between the supports constituting the housing, the powder generated by sliding between the circuit board and the support reaches the surface of the circuit board. Realization of an electronic device having a configuration that can be suppressed is desired.

One embodiment of the present invention is an electronic device including a circuit board and a housing including two supporting bodies. In the electronic device, the circuit board includes a concave portion formed at a position in contact with the outer periphery of the circuit board, and a convex portion formed at a position in contact with the outer periphery and adjacent to the concave portion. The body is arranged so that at least one of the body comes into contact with the bottom surface of the recess, and the circuit board is sandwiched in the thickness direction at a position where the body comes into contact, and the circuit board is fixed in the housing.
According to another aspect of the present invention, the circuit board includes a plurality of the concave portions and the convex portions, and the concave portions and the convex portions are alternately arranged along the outer periphery of the circuit board. .
According to another aspect of the invention, the convex portion is located at least at a corner of the circuit board.
According to another aspect of the invention, the support is in contact with a conductive pattern formed on the bottom surface.
According to another aspect of the present invention, the conductive pattern is a ground pattern.
According to another aspect of the present invention, there is provided a space partitioned by the inner surface of the support, the side surface of the recess, and the bottom surface.
According to another aspect of the present invention, an adhesive material is provided on a part of the inner surface of the space.

It is a figure which shows the structure of the electronic device which concerns on embodiment of this invention. It is a figure which shows the structure of the electronic device which concerns on embodiment of this invention. It is a figure which shows the structure of the circuit board mounted in the electronic device which concerns on embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of an electronic device 100 according to an embodiment of the present invention. The electronic device 100 according to the present embodiment is, for example, an electronic control unit (ECU, Electronic Control Unit) mounted on a vehicle. However, the configuration of the electronic device of the present invention is not limited to this, and widely used in general electronic devices. Can be applied.

  FIG. 1 is a top view of the electronic device 100. The electronic apparatus 100 includes a housing 101, a circuit board 105 (shown by dotted lines) housed in the housing 101, and a connector 102 mounted on the circuit board 105.

  2 (a), 2 (b), and 2 (c) are cross-sectional views taken along arrows AA, BB, and CC, respectively, of the electronic device 100 shown in FIG. 1 (a). It is an arrow view. FIG. 3 is a perspective view of the circuit board 105 accommodated in the electronic apparatus 100.

  The housing 101 includes two supports, a cover 101a and a base 101b. The cover 101a and the base 101b are fixed to each other by four screws 103a, 103b, 103c, and 103d to form an internal cavity. The circuit board 105 is accommodated in the internal cavity.

  Next, details of the circuit board 105 will be described. The circuit board 105 is a rectangular flat plate, for example, a multilayer board (for example, a multilayer printed wiring board) in which three insulating layers 206, 216, and 226 are stacked. Here, the upper surface of the insulating layer 206 in FIG. 2A is referred to as a front surface of the circuit board 105, and the lower surface of the insulating layer 226 is referred to as a back surface of the circuit board 105. An electrical component (not shown) that constitutes an electronic circuit is mounted on the front surface and / or the back surface of the circuit board 105, and the electronic circuit is connected to an external device (via an connector 102 mounted on the circuit board 105). For example, it is electrically connected to an external power supply device or the like, and power is supplied from the power supply or the like, or information is transmitted between other devices (not shown).

  In addition to the conductive patterns 217, 227, and 237, various conductive patterns for signals may be formed between the front surface, the back surface, and / or the insulating layers 206, 216, and 226 of the circuit board 105. In order to simplify the drawing and facilitate understanding, the illustration thereof is omitted in FIGS. 2 (a), (b), (c), and FIG.

  In addition, as shown in FIG. 3, the circuit board 105 includes a region that does not have the insulating layer 206 in the vicinity of the outer periphery on the front side, whereby the thickness of the insulating layer 206 and the conductive pattern 217 is divided. Only six recesses 216A, 216B, 316C, 316D, 216E, and 316F configured to be recessed from the front surface of the insulating layer 206 are provided. Each recess is formed at a position where a part thereof is in contact with the outer periphery of the circuit board 105 (for example, the outermost periphery of the insulating layer 216 which is the inner layer in FIG. 3), and the side surface side of the circuit board 105 (for example, FIG. A concave portion is formed so that the left side of the concave portion 216B of a) opens.

  In addition, the circuit board 105 includes a region that does not have the insulating layer 226 on the outer periphery on the back surface side, and is configured to be recessed from the back surface by the thickness of the insulating layer 226 and the conductive pattern 227. 6 recesses (for example, the recesses 216b and 216e in FIG. 2A are included). The six concave portions on the back surface side are formed at positions facing the six concave portions formed on the front surface side.

  In addition, as shown in FIG. 3, the circuit board 105 has five convex portions 206a, 206b, 306c, 306d, which are constituted by regions where the insulating layer 206 is provided up to a position in contact with the outer periphery on the front side. 206e. Each convex part is formed at a position where a part of the convex part is in contact with the outer periphery of the circuit board 105, and is arranged so as to be adjacent to each concave part formed on the front surface side with respect to the bottom surface of the concave part. A convex structure. Then, along the circumferential direction of the outer periphery of the circuit board 105, the concave portion 216A, the convex portion 206a, the concave portion 216B, the convex portion 206b, the concave portion 316C, the convex portion 306c, the concave portion 316D, the convex portion 306d, the concave portion 216E, the convex portion 206ed, The concave portions and the convex portions are alternately arranged so as to be sequentially arranged with the concave portions 316F. In order to maintain the strength of the circuit board 105, the protrusions 206b and 206d are formed at the corners of the circuit board 105.

  Further, the circuit board 105 has five convex portions (for example, convex portions in FIGS. 2B and 2C) constituted by regions where the insulating layer 226 is provided up to a position in contact with the outer periphery on the back surface side. Part 226a, 226b, and 226e), a part of which is formed at a position in contact with the outer periphery of the circuit board 105 and adjacent to each of the recesses formed on the back surface side. And a convex structure with respect to the bottom surface of the concave portion. Then, similarly to the arrangement of the concave and convex portions on the front side, the concave and convex portions are alternately arranged along the circumferential direction of the outer periphery of the circuit board 105. Note that the convex portions are formed on the corners of the circuit board 105 in order to maintain the strength of the circuit board 105 also on the back surface side of the circuit board 105.

  In addition, a conductive pattern (for example, a ground pattern) is formed on the bottom surface of each of the recesses formed on the front side and the back side of the circuit board 105. For example, as shown in FIG. Conductive patterns 208a, 208b, 308c, 308d, 208e, and 308f are formed on the front side of each of 216B, 316C, 316D, 216E, and 316F. Further, each conductive pattern is the same as the conductive pattern formed between the insulating layer 206 and the insulating layer 216 by the connecting portions 310a, 310b, 310c, 310d, 310e, and 310f formed on the front surface side of the concave portion. 217 and the like are electrically connected. Note that the conductive pattern (conductive pattern, for example, a ground pattern) is also provided on the bottom surface of the concave portion on the back surface side of the circuit board 105 at positions facing the conductive patterns 208a, 208b, 308c, 308d, 208e, and 308f on the front surface side. Patterns 209a and 209b are formed). The conductive pattern on the back surface side is also electrically connected to, for example, a conductive pattern 227 formed between the insulating layer 216 and the insulating layer 226 to form a part of the control circuit.

  A part of the inner surface of each of the cover 101a and the base 101b constituting the housing 101 is in contact with each of the conductive patterns formed in the concave portions on the front surface side and the back surface side of the circuit board 105. Arranged. A part of the inner surface of the cover 101a is in contact with the bottom surface of each of the recesses formed on the front surface side of the circuit board 105 in the contact areas 110a, 110b, 110c, 110d, 110e, and 110f indicated by hatching in FIG. It touches. A part of the inner surface of the base 101b is formed on the back surface side of the circuit board 105 at a position on the back surface side facing the contact areas 110a, 110b, 110c, 110d, 110e, and 110f. It is in contact with the recess. Then, the screws 103a, 103b, 103c, and 103d (FIG. 1) for fixing the cover 101a and the base 101b are fastened, so that the cover 101a and the base are brought into contact with each other on the front surface side and the back surface side. 101b presses and clamps the circuit board 105 in the thickness direction (the vertical direction in FIGS. 2A, 2B, and 2C), and the circuit board 105 is fixed inside the housing 101. The

  The conductive patterns formed in the recesses on the front side and the back side where the cover 101a and the base 101b come into contact are, for example, ground patterns, and the casing 101 (that is, the cover 101a and the base 101b) is used as the ground pattern. If, for example, a conductive material such as metal (for example, aluminum) is used, the ground line of the electronic circuit formed on the circuit board 105 is connected to the power supply provided outside the electronic device 100 via the housing 101. Can be connected to the ground line.

  Here, in general, when the circuit board is sandwiched and fixed by two supports constituting the casing, for example, when the environmental temperature repeatedly fluctuates, the linear expansion coefficient of the material constituting the support and the circuit board Due to this difference, a relative positional shift occurs between the support and the circuit board, and both slide. When such sliding occurs, the support and the material portion or the conductive pattern of the circuit board sandwiched by the support are rubbed together, and the surface of the material portion or the conductive pattern is worn away. Resin powder derived from the constituent resin material or metal powder derived from the metal constituting the conductive pattern may be generated. Such resin powder or metal powder may enter a circuit contact or the like to cause a contact failure or short circuit between wirings, thereby causing an abnormality in circuit operation.

  Also in the electronic device 100, from the contact area between the cover 101a and the base 101b and the conductive patterns formed in the concave portions on the front surface side and the back surface side of the circuit board 105, the metal material of the conductive pattern is used. Metal powder derived from can be generated. However, in the present electronic device 100, the contact areas of the cover 101a and the base 101b and the respective conductive patterns are located in the respective recesses, whereby the metal powder is applied to the front and back surfaces of the circuit board 105. It is configured to prevent movement of the body. Hereinafter, the configuration for suppressing the movement of the metal powder will be described by taking the concave portion 216B of the circuit board 105 shown in FIGS. 2A and 2C as an example.

  The contact area between the conductive pattern 208b formed in the recess 216B of the circuit board 105 and the cover 101a is equal to the thickness of the insulating layer 206 and the conductive pattern 217 rather than the surface of the insulating layer 206 constituting the front surface of the circuit board 105. It is located only on the lower side in the figure. Accordingly, a step corresponding to the thickness is provided between the contact area and the front surface of the circuit board 105, and the contact area is a wall surface 255 ( The insulating layer 206 in FIG. 2A on the left side in the figure), the wall surface 256 constituted by the convex part 206a (the right side in the figure of the convex part 206a in FIG. 2C), and the wall surface constituted by the convex part 206b. 257 (the left side surface of the convex portion 206b in FIG. 2C) and the inner surface of the cover 101a are surrounded.

  As a result, the side surfaces (wall surfaces 255, 256, 257) of the recess 216B and the inner surface of the cover 101a function as a barrier that inhibits the movement of the metal powder generated in the contact area, and further, the bottom surface of the recess 216B, The metal powder is confined in the spaces 230, 231 and 232 formed by the side surfaces (wall surfaces 255, 256 and 257) and the inner surface of the cover 101a. Thereby, the direct movement of the metal powder to the front surface of the circuit board 105 can be prevented. The metal powder confined in the spaces 230, 231 and 232 is attached or deposited on the side surface (wall surface 255, 256, 257), the bottom surface and the inner surface of the cover 101a of the recess 216B. The re-scattering of the metal powder can be suppressed, whereby the amount of the metal powder reaching the front surface of the circuit board 105 can be greatly reduced.

  Here, only one recess 216B formed on the circuit board 105 has been described, but not only the recess 216B but also other recesses formed on the front surface side and the back surface side of the circuit board 105 The same operations and effects as those of the recess 216B are provided. In the present embodiment, the two convex portions 206a and 206b are provided on both sides of the concave portion 216B (the right side and the left side of the concave portion 216B shown in FIG. 2C). However, the present invention is not limited to this. Even if only the convex portion is provided (for example, only the convex portion 206a is provided), a certain effect can be obtained to restrict the movement of the metal powder.

  As described above, the electronic device 100 according to the present embodiment is an electronic device including the circuit board 105 on which an electronic circuit is mounted and the housing 101 including the two supports 101a and 101b. The circuit board 105 is adjacent to the recesses 216A, 216B, 316C, 316D, 216E, 316F, 216a, 216b, and 216e formed in a position in contact with the outer periphery of the circuit board. And convex portions 206a, 206b, 206c, 206d, 206e, 226a, 226b, and 226e that are in contact with the outer periphery, and at least one of the two supports 101a and 101b is in contact with the bottom surface of the concave portion. The circuit board 105 is sandwiched in the thickness direction at the corresponding contact position, and the circuit board 105 is placed in the housing 101. Fixing the road substrate 105. As a result, the powder generated from the portion where the two supports (101a, 101b) and the respective recesses come into contact is prevented from reaching the front side and / or the back side of the circuit board 105. A malfunction of the formed electronic circuit can be prevented.

  In the circuit board 105 of the electronic device 100, only the insulating layer 216 constituting the inner layer of the circuit board 105 is sandwiched between the supports 101 a and 101 b, and the region where the support abuts is the area of the insulating layer 216. A free end (for example, the right end portion and the left end portion of the insulating layer 216 shown in FIG. 2A) that is near the side surface and is not fixed in the vertical direction by the insulating layers 206 and 226 on the front side and the back side. It is an area including a part to be configured. As a result, the amount of displacement due to contraction and expansion due to temperature change of the circuit board is greatly reduced as compared with the case where the entire circuit board 105 composed of a plurality of insulating layers is sandwiched by the support in the thickness direction. As a result, the stress generated in the contact area between the circuit board 105, the cover 101a, and the base 101b can be substantially reduced. Further, in the electronic device 100, the central part of the circuit board 105 (for example, the front side of the insulating layer 206 and the back side of the insulating layer 226) constituting the main part of the control circuit mounted on the circuit board 105 is Since the cover 101a and the base 101b, which are two supports, are not directly sandwiched by the support 101, damage to the control circuit due to direct stress from the support can be avoided. Can improve the environmental resistance performance.

  In the present embodiment, each of the conductive patterns is a ground pattern. However, the present invention is not limited to this, and some or all of the conductive patterns are not conductive patterns (for example, for heat conduction). Pattern).

  In addition, a soft metal plate such as a copper plate can be interposed between each of the conductive patterns and the support that sandwiches these conductive patterns. As a result, the cover 101a and the base 101b are configured to be in pressure contact with the metal plate. For example, even if the circuit board 105 or the housing 101 is displaced due to a change in environmental temperature, the metal plate is deformed. And since the said displacement is absorbed, sliding of members can be suppressed substantially and generation | occurrence | production of powder can be reduced. Note that if the thickness of the metal plate is, for example, equal to or greater than the thickness of one insulating layer constituting the circuit board, the displacement of the circuit board 105 and the casing 101 can be effectively absorbed. In addition to the case where the metal plate is disposed on the conductive pattern, for example, even when the thickness of the conductive pattern is increased, a certain displacement absorbing effect can be obtained and the generation of powder can be reduced. Can do.

  Further, a configuration in which a conductive pattern is not provided in a portion on each concave portion where the cover 101a and the base 101b, which are two supports, contact each other, that is, a material portion (for example, a resin material) of the insulating layer 216 constituting the concave portion is covered. It is also possible to adopt a configuration in which the sheet is directly sandwiched between 101a and the base 101b. Thereby, even when the powder of the resin material (insulator) constituting the circuit board 105 is generated from the contact portion between the cover 101a and the base 101b and the material portion of the insulating layer 216, the bottom surface of the recess is formed. Since the powder of the resin material can be captured by the side surface and the like, the resin material powder is effectively prevented from reaching the front surface and the back surface of the circuit board 105, for example, in the connector 102. Contact failure caused by the powder can be prevented in advance.

  Further, in the present embodiment, the concave and convex portions are arranged so as to circulate over three side surfaces excluding the side surface on the side where the connector 102 is mounted. As long as the part is formed on any one of the side surfaces constituting the circuit board 105, as long as the peripheral part is sandwiched between the supports constituting the housing, the powder generated in the sandwiching part The effect which prevents the movement of can be acquired.

  Furthermore, in this embodiment, six concave portions and five convex portions are provided on each of the front surface side and the back surface side of the circuit board 105. However, the present invention is not limited to this, and any one of the periphery of the circuit board 105 is provided. If the said recessed part and convex part are formed in the location, a fixed effect can be acquired in suppression of a movement of powder. Further, for example, when an electronic circuit is not formed on the back surface of the circuit board 105, the concave portion and the convex portion may not be provided on the back surface side of the circuit board 105.

  Further, an adhesive material (for example, an adhesive tape or the like) may be applied to any of the surfaces constituting the spaces 230, 231, 232 (for example, a part of the wall surfaces 255, 256, 257, a part of the inner surface of the cover 101a, etc.). By providing (adhesive paint), the powder generated in the housing can be fixed to the adhesive. Thereby, the dispersion of powder can be effectively suppressed, and further, the wiring and electrical components mounted on the circuit board 105 can be protected from contamination by powder.

  In the circuit board 105 of the present embodiment, as shown in FIGS. 2A and 2C, the angle formed by the bottom surface of the recess 216B and the wall surfaces 255, 256, and 257 is a right angle. An acute angle can also be set. With such a configuration, since the powder is easily captured at the acute angle portion formed by the wall surface, the wiring and electrical components mounted on the circuit board 105 are more effectively protected from contamination by the powder. be able to.

  Further, if the positions, places, lengths, and the like of the concave portions and convex portions formed on the circuit board 105 are changed for each type of electronic circuit mounted on the circuit board 105, the shape of the circuit board 105 is changed. Since the type of the electronic circuit mounted on the circuit board can be easily discriminated simply by visually recognizing the error, for example, mistakes such as the circuit board 105 mounted on the housing 101 can be prevented.

  In this embodiment, a multilayer board is used as the circuit board 105. However, the present invention is not limited to this. For example, a single-layer printed board is used. It is very good to have a convex part. Furthermore, by providing a sealing material such as waterproof grease at a portion where the cover 101a and the base 101b are in contact with each other, it is possible to suppress the intrusion of dust or a minute amount of moisture into the inside.

  Note that the present invention is not limited to the above-described embodiment, and can be modified and used without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 100 ... Electronic device, 101 ... Housing, 101a ... Cover, 101b ... Base, 102 ... Connector, 103a, 103b, 103c, 103d ... Screw, 105 ... Circuit board 110a, 110b, 110c, 110d, 110e, 110f ... contact area, 206, 216, 226 ... insulating layer, 206a, 206b, 306c, 306d, 206e, 226a, 226b ... convex, 216A 216B, 316C, 316D, 216E, 316F, 216a, 216b, 216e ... recess, 207, 217, 227, 237, 208a, 208b, 308c, 308d, 208e, 209a, 209b, 209e ... conductive pattern, 255, 256, 257 ... wall surface, 230, 231, 232 ... space, 10a, 310b, 310c, 310d, 310e, 310f ··· connection.

Claims (7)

An electronic device comprising a circuit board and a housing composed of two supports,
The circuit board includes a concave portion formed at a position in contact with the outer periphery of the circuit board, and a convex portion formed at a position in contact with the outer periphery and adjacent to the concave portion,
The two supports are arranged so that at least one of them abuts against the bottom surface of the recess, and the circuit board is sandwiched in the thickness direction at the corresponding contact position to fix the circuit board in the housing. ,
Electronic equipment. The circuit board includes a plurality of the concave portions and the convex portions,
Each of the recesses and the protrusions are alternately arranged along the outer periphery of the circuit board.
The electronic device according to claim 1. The convex portion is located at least at a corner of the circuit board.
The electronic device according to claim 1. The support is in contact with a conductive pattern formed on the bottom surface;
The electronic device according to claim 1. The conductive pattern is a ground pattern;
The electronic device according to claim 4. A space partitioned by the inner surface of the support, the side surface of the recess, and the bottom surface;
The electronic device according to claim 1. An adhesive material is provided on a part of the inner surface of the space.
The electronic device according to claim 6.

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