JP2014013805A - Control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control unit which is not easily damaged by vibrations.SOLUTION: An electronic component is mounted on a control board. A case including a support plate and a cover houses the control board. A bracket integrally formed with the support plate extends outward from an edge of the support plate. The bracket includes a flat plate portion and a stress relaxation part which connects the flat plate portion with the support plate. In the stress relaxation part, the rigidity of the bracket is lower compared to the flat plate portion of the bracket.

Description

  The present invention relates to a control unit, and more particularly to an in-vehicle control unit.

  The case of the control unit for in-vehicle use requires functions such as dust proofing, vibration proofing, and heat radiation depending on the installation environment. Resin cases, aluminum die cast cases, sheet metal cases and the like are used according to these requirements. The control unit is provided with a bracket (also referred to as “stay”) for fixing to the vehicle body chassis. The bracket is formed integrally with the case or formed as a separate member and then fixed to the case.

  A control unit that can firmly fix a printed circuit board in a case is disclosed in Patent Document 1. In the control unit disclosed in Patent Document 1, the protrusion formed on the outer peripheral portion of the printed circuit board is engaged with a through hole or a recess provided in the case. The case is composed of a casing and a cover, and a printed circuit board is accommodated between them.

  A plurality of brackets extend outward from the edge of the flat cover. The bracket is composed of the same flat plate as the flat cover. A mounting hole for the vehicle body chassis is formed in the bracket. Since the printed board is firmly fixed to the case, generation of noise due to vibration of the printed board can be prevented.

JP 2002-271057 A

  The control unit is fixed to the vehicle body chassis by passing a fastener such as a screw through a through hole provided in the bracket. When using a sheet metal case, the bracket and the case are often integrally molded from the viewpoint of ease of processing and cost. The vibration of the vehicle body chassis is transmitted to the printed circuit board through the bracket and the case. When the printed circuit board vibrates, cracks may occur in the solder fixing the electronic component. Further, if a stress greater than the rated value is applied to the connection portion between the bracket and the case, a crack may occur in the connection portion.

  An object of the present invention is to provide a control unit that is not easily damaged by vibration.

According to a first aspect of the invention,
A control board mounted with electronic components;
A case including a support plate and a cover, and housing the control board;
A bracket formed integrally with the support plate and extending outward from an edge of the support plate;
The bracket includes a flat plate portion, and a stress relaxation portion that connects the flat plate portion and the support plate, and the stress relaxation portion has a lower rigidity of the bracket than the flat plate portion. A control unit is provided.

  In the control unit according to the second aspect of the present invention, the stress relaxation portion has a curved three-dimensional shape in which the flat plate portion is continuous with the support plate.

  In the control unit according to the third aspect of the present invention, notches directed inward from the edge of the support plate are provided at both ends of the boundary line between the bracket and the support plate.

  In the control unit according to the fourth aspect of the present invention, the cover and the control board are fastened together with the support plate, and the cover has a three-dimensional shape that does not contact the bracket.

  By adopting the configuration of the control unit according to the first aspect, the vibration of the vehicle body chassis on which the control unit is mounted is absorbed by the stress relaxation portion of the bracket. Thereby, the vibration of a support plate and a control board can be suppressed.

  As in the control unit according to the second aspect, by making the stress relaxation portion a curved solid shape, vibration can be absorbed more than in a configuration in which the flat plate portion is directly continuous with the edge of the support plate. .

  By providing a notch as in the control unit according to the third aspect, the concentration of stress applied in the vicinity of the boundary line between the bracket and the support plate can be reduced.

  By using a structure in which the cover and the bracket do not contact each other as in the control unit according to the fourth aspect, it is possible to prevent the generation of abnormal noise (chattering noise) due to vibration.

1A is a schematic view of a state in which a control unit according to an embodiment is attached to a vehicle body chassis, and FIG. 1B is an exploded perspective view of the control unit according to the embodiment. 2A is a plan view of a support plate of the control unit according to the embodiment, FIG. 2B is a cross-sectional view taken along one-dot chain line 2B-2B of FIG. 2A, and FIG. It is sectional drawing of a corresponding part. FIG. 3A is a perspective view of the bracket of the control unit according to the embodiment and a case in the vicinity thereof, and FIG. 3B is a cross-sectional view of the bracket and the case in the vicinity thereof.

  FIG. 1A is a schematic view showing a state in which the control unit 10 according to the embodiment is attached to the vehicle body chassis 20. The control unit 10 according to the embodiment includes a case 11 and a plurality of, for example, two brackets 12 drawn from the case 11. The bracket 12 is fixed to the vehicle body chassis 20 by passing a fastener 13 such as a bolt through a through-hole formed in the bracket 12.

  FIG. 1B shows an exploded perspective view of the control unit 10 according to the embodiment. The support plate 15 and the cover 16 constitute a case 11 (FIG. 1A). A control board (printed board) 17 is accommodated between the support plate 15 and the cover 16. For example, sheet metal processing is applied to the formation of the support plate 15 and the cover 16. For the support plate 15, for example, a galvanized steel plate having a thickness of 2 mm is used. For the cover 16, for example, a galvanized steel sheet having a thickness of 0.6 mm is used.

The control board 17 has a substantially rectangular planar shape, and screw holes are formed in the four corners. A connector 41 is mounted in the vicinity of one edge of the control board 17. Terminals of the connector 41 are connected to various electronic components mounted on the control board 17, such as an electronic control unit (ECU). The cover 16 is provided with a through hole 50 for screwing, and the support plate 15 is provided with a screw hole 33. The screw hole 33 is tapped. The cover 16 and the control board 17 are fastened together with the support plate 15 by the screws 55. As a result, the cover 16 and the control board 17 are fixed to the support plate 15.

  The support plate 15 has a three-dimensional shape (bathtub shape) in which the upper surface 30 in the vicinity of the outer peripheral portion is slightly higher than the upper surface 31 in the inner back. The plurality of screw holes 33 are arranged in the upper surface 30 in the vicinity of the outer peripheral portion. The outer peripheral portion of the control board 17 contacts the upper surface 30 near the outer peripheral portion of the support plate 15. By making the upper surface 31 of the inner back portion of the support plate 15 lower than the upper surface 30 in the vicinity of the outer peripheral portion, a space for accommodating components, protrusions, and the like attached to the back surface of the control substrate 17 is formed. 17 is secured.

  The bracket 12 extends outward from the edge of the support plate 15. The bracket 12 is formed integrally with the support plate 15. Specifically, a three-dimensional shape of the support plate 15 and the bracket 12 is obtained by performing sheet metal processing on one metal plate. The bracket 12 includes a flat plate portion 12A and a stress relaxation portion 12B. The flat plate portion 12A continues to the support plate 15 via the stress relaxation portion 12B.

  The flat plate portion 12 </ b> A maintains, for example, a posture parallel to the upper surface 30 of the support plate 15. The stress relaxation part 12B has a curved three-dimensional shape. The curved portion has a shape along, for example, a part of a cylindrical surface, a part of an elliptical cylindrical surface, or the like. A through hole 34 for screwing is formed in the flat plate portion 12A. The control unit 10 is fixed to the vehicle body chassis 20 (FIG. 1A) by inserting the fastener 13 (FIG. 1A) into the through hole. At both ends of the boundary line between the bracket 12 and the support plate 15, notches 35 directed inward from the edge of the support plate 15 are formed.

  The cover 16 covers the electronic component mounted on the upper surface of the control board 17. An opening 52 is formed at a position corresponding to the connector 41 on the side surface of the cover 16. The opening 52 exposes the terminal insertion portion of the connector 41. A bulging portion 51 is provided on a side surface of the cover 16 at a position corresponding to the bracket 12. The bulging portion 51 avoids the cover 16 coming into contact with the bracket 12.

  FIG. 2A shows a plan view of the support plate 15. 2B is a cross-sectional view taken along one-dot chain line 2B-2B in FIG. 2A. The support plate 15 has a substantially rectangular planar shape. Screw holes 33 are formed at the four corners of the upper surface 30 near the outer periphery of the support plate 15. The inner upper surface 31 is lower than the upper surface 30 near the outer periphery.

  The brackets 12 respectively extend outward from the mutually opposing edges of the support plate 15. Each of the brackets 12 includes a flat plate portion 12A and a stress relaxation portion 12B. The flat plate-like portion 12A continues to the support plate 15 via the stress relaxation portion 12B. A notch 35 is formed at both ends of the boundary line 19 between the bracket 12 and the support plate 15 from the edge 18 of the support plate 15 toward the inside. For this reason, the boundary line 19 that connects the tips (the deepest portions) of the notches 35 at both ends of the boundary line 19 is positioned inside the edge 18 of the support plate 15.

  As shown in FIG. 2B, the stress relaxation portion 12B has a curved three-dimensional shape. Specifically, the stress relieving portion 12 </ b> B is temporarily bent downward as it gets away from the boundary line 19 and reaches a position lower than the back surface 32 of the support plate 15. Thereafter, the direction of the curve is changed and the flat portion 12A is smoothly continued. As described above, the stress relaxation portion 12B includes portions that are curved in directions opposite to each other. The flat plate portion 12 </ b> A is parallel to the upper surface 30 of the support plate 15. A through hole 34 for screwing is formed in the flat plate portion 12A.

  The stress relaxation portion 12B has a lower rigidity of the bracket 12 than the flat plate portion 12A. Specifically, the rigidity of the bracket 12 having a cantilever structure with the position of the boundary line 19 as a fixed end is a flat plate having a cantilever structure with the boundary between the stress relaxation portion 12B and the flat plate portion 12A as a fixed end. It is lower than the rigidity of the portion 12A.

  FIG. 2C shows a cross-sectional view of the support plate and bracket of the control module according to the comparative example. 2C are assigned the same reference numerals as those assigned to the corresponding components in the cross-sectional view of the support plate and bracket according to the embodiment shown in FIG. 2B. In the comparative example, the bracket 12 is composed of only a flat plate portion, and no stress relaxation portion is provided. That is, the bracket 12 extends in a flat plate shape (straight) outward from the boundary line 19. An image obtained by vertically projecting the bracket 12 according to the comparative example of FIG. 2C onto a virtual plane parallel to the upper surface 30 is congruent with an image obtained by vertically projecting the bracket 12 according to the embodiment illustrated in FIG. It is. In the comparative example, a notch 35 is formed, and the boundary line 19 is located on the inner side of the edge 18 of the support plate 15.

  The rigidity of the bracket 12 including the stress relaxation portion 12B of the control unit 10 according to the embodiment is lower than the rigidity of the bracket 12 of FIG. 2C having a three-dimensional shape extending outward from the edge of the support plate 15 in a flat plate shape. By reducing the rigidity of the bracket 12, the vibration of the vehicle body chassis 20 (FIG. 1A) is not easily transmitted to the support plate 15. Thereby, the vibration of the support plate 15, the control board 17 (FIG. 1B), and the cover 16 is suppressed.

  When one of the support plate 15 and the bracket 12 is fixed and a load is applied to the other, stress is concentrated near both ends of the boundary line 19 between the bracket 12 and the support plate 15. According to the simulation conducted by the inventor, it was found that the maximum stress applied to the stress concentration portion is reduced by providing the stress relaxation portion 12B. By reducing the applied maximum stress, the occurrence of cracks in the vicinity of the boundary line 19 can be prevented. Furthermore, it was found that the maximum stress applied to the stress concentration location can be further reduced by providing the notch 35.

  FIG. 3A is a perspective view of the bracket 12 and the support plate 15 and the cover 16 in the vicinity thereof. The inner surface near the lower end (near the opening) of the cover 16 and the end surface 18 of the support plate 15 face each other. A region corresponding to the bracket 12 in the lower end of the cover 16 bulges outward, and a bulge portion 51 is formed.

  FIG. 3B shows a cross-sectional view of the bracket 12 and the support plate 15 and the cover 16 in the vicinity thereof. Of the side surfaces of the cover 16, side surfaces other than the portion corresponding to the bracket 12 are indicated by broken lines. As for the side surfaces other than the portion corresponding to the bracket 12, the end surface 18 of the support plate 15 and the inner surface of the side surface of the cover 16 face each other with a gap therebetween. The stress relaxation portion 12B of the bracket 12 extends outward from the boundary line 19 and is curved downward. This curved portion protrudes beyond the end face 18 of the support plate 15.

  Corresponding to the protruding portion of the stress relaxation portion 12B, the vicinity of the lower end of the side surface of the cover 16 bulges outward. A gap is secured between the inner surface of the bulging portion (bulging portion) 51 and the bracket 12. For this reason, the cover 16 does not contact the bracket 12. Thereby, generation | occurrence | production of the abnormal sound (billing sound) resulting from the contact with the bracket 12 and the cover 16 can be prevented.

  In the above embodiment, as shown in FIG. 2B, the stress relaxation portion 12B is provided with a pair of portions that are curved in opposite directions. Two or more sets of the curved portions may be provided. For example, the cross section of the stress relaxation portion 12B may be a meander shape.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 Control unit 11 Case 12 Bracket 12A Flat plate-like part 12B Stress relaxation part 13 Fastener 15 Support plate 16 Cover 17 Control board (printed board)
18 Edge (end face) of support plate
19 Boundary line 20 between support plate and bracket 20 Car body chassis 30 Upper surface 31 near outer periphery Upper surface 32 in inner back portion Back surface of support plate 33 Screw hole 34 Through hole 35 Notch 40 Screw through hole 41 Connector 50 Through hole 51 Bulge 52 Opening 55 Screw

Claims (4)

A control board mounted with electronic components;
A case including a support plate and a cover, and housing the control board;
A bracket formed integrally with the support plate and extending outward from an edge of the support plate;
The bracket includes a flat plate portion, and a stress relaxation portion that connects the flat plate portion and the support plate, and the stress relaxation portion has a lower rigidity of the bracket than the flat plate portion. Controller unit.   2. The control unit according to claim 1, wherein the stress relaxation portion has a curved three-dimensional shape in which the flat plate portion is continuous with the support plate.   3. The control unit according to claim 1, wherein a notch directed inward from an edge of the support plate is provided at both ends of a boundary line between the bracket and the support plate.   The control unit according to any one of claims 1 to 3, wherein the cover and the control board are fastened to the support plate, and the cover has a three-dimensional shape that does not contact the bracket.

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