JP2015060959A - Electronic control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent poor screw-thread fit of a screw, which is caused by corotation occurring when another screw is fastened.SOLUTION: An electronic control device 1 comprises: a housing 3 composed of a case 4 and a cover 5, for storing a printed wiring board 2 with an electronic component 6 being mounted; a plurality of screw holes 25a-25d formed in the case 4, for screwing lockscrews 34; and a plurality of screw insertion holes 35a-35d formed in the cover 5, for allowing shank parts of the lockscrews 34 to be inserted, in which the screw holes and the screw insertion holes are opposed one another and the lockscrews 34 are screwed with the screw holes and the case 4 and the cover 5 are fastened and fixed by the plurality of lockscrews. The screw insertion holes of the cover 5 other than one screw insertion hole of the cover 5, which allows the lockscrew to be inserted in order to be firstly screwed, are formed in shapes each having a larger clearance in a corotation direction with the cover than each clearance in each of other directions.

Description

  The present invention relates to an electronic control device that is mounted on an automobile and used to control an engine, a brake, and the like.

  An automobile uses an engine control device as an electronic control device. (For example, patent document 1).

  In Patent Document 1, an engine control device includes a printed wiring board 1 constituting a printed circuit board and the printed circuit board 1 as disclosed in paragraphs [0009], [0029], [0031] and FIGS. It has a case 2 that is a housing for storing the wiring board 1 and a cover 3 that covers the printed wiring board 1 fixed in the case 2 and is attached to the case 2.

  Cover mounting screw holes (hereinafter referred to as screw screw holes) 21 are formed at the four corners of the case 2. Further, fixing screw mounting holes (hereinafter referred to as screw insertion holes) 29 through which the fixing screws 28 are inserted are formed at the four corners of the cover 3 and at positions facing the screw screw holes 21.

  After mounting the printed wiring board 1 in the case 2, the cover 3 is overlaid on the case 2, the positions of the screw insertion holes 29 and the screw screw holes 21 are aligned, and the shaft portion of the fixing screw 28 is The cover 3 is screwed into the screw screw hole 21 via the screw insertion hole 29, and the cover 3 is fixed to the case 2 with a fixing screw 28.

JP 2010-56489 A

By the way, when the case 2 and the cover 3 are screwed with the fixing screws 28 at a plurality of locations as described above, there are the following problems.
(1) When a plurality of locations are screwed in order, a position between the other screw insertion holes 29 and the screw screw holes 21 that are not yet screwed due to a so-called accompanying phenomenon at the time of the first screwing. A shift may occur, and the cover 3 may block a part of the screw screw hole 21 so that the fixing screw 28 cannot be screwed into the screw screw hole 21.
(2) In order to enable the fixing screw 28 to be screwed into the screw screw hole 21 even when a slight displacement between the screw insertion hole 29 and the screw screw hole 21 occurs due to the rotation. It is conceivable to increase the diameter of the screw insertion hole 29. However, if the diameter of the screw insertion hole 29 is increased, the effective area of tightening the cover 3 by the head of the fixing screw 28 is reduced. The bond strength of the cover 3 is weakened.

  The present invention solves the above-mentioned conventional problems, and without reducing the effective tightening area for the cover or the like by a fixing screw, and by the accompanying phenomenon, between the screw insertion hole on the cover side and the screw screwing hole on the case side. The fixing screw can be surely inserted into the screw screw hole even when a positional deviation occurs between them.

The housing for housing the circuit board on which the electronic component is mounted is composed of at least two members, one of which is provided with a plurality of screw screw holes for screwing the fixing screw, and the other member is provided with the shaft of the fixing screw. A plurality of screw insertion holes through which the portion is inserted are opposed to the plurality of screw screw holes, and a shaft portion of the fixing screw is screwed into the screw screw hole through the screw insertion hole. In an electronic control device for fastening and fixing at least two members with a fixing screw of
For the screw insertion hole through which the fixing screw for initial tightening is inserted, the other screw insertion hole is in the direction in which the cover is rotated by the fixing screw screwed into the screw screwing hole first, from the other direction. Is also formed into a shape with a large clearance.

  Even if the position of the other screw insertion hole and the screw screwing hole is shifted due to the rotation of the cover by the fixing screw first screwed into the screw screwing hole, the other screw insertion hole and screw screwing hole are Thus, it is possible to maintain the state of being completely overlapped with each other by the clearance, and to surely screw the fixing screw into the screwing hole of the second and subsequent fixing screws.

The exploded perspective view of an automatic control device. The perspective view which shows the positioning mechanism of a housing | casing. The top view of a cover. The top view of the state which attached the cover to the case. Explanatory drawing which shows the relationship between the 1st screw screw hole in the state positioned by the positioning mechanism, and the 1st screw insertion hole. Explanatory drawing which shows the relationship between the 3rd screwing hole of the state positioned with the positioning mechanism, and the 3rd screw insertion hole. Explanatory drawing which shows the relationship between the 3rd screwing hole and the 3rd screw insertion hole of the state which the accompanying rotation generate | occur | produced.

Hereinafter, an embodiment of an electronic control device of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view of the electronic control device 1. The electronic control device 1 includes a printed wiring board 2 constituting a circuit board and a housing 3 that houses the printed wiring board 2.

  The housing 3 includes a case 4 to which the printed wiring board 2 is attached and a cover 5 that covers the printed wiring board 2 attached to the case 4 and is attached to the case 4.

  The printed wiring board 2 is based on an insulating resin material such as glass epoxy resin, for example, and forms an electric circuit portion by forming a wiring circuit pattern on the front and back surfaces and mounting the electronic component 6 thereon.

  As the electronic component 6 mounted on the printed wiring board 2, various electronic components such as a capacitor, a coil, a transistor, and a semiconductor IC for constituting the unit are used in the engine control unit.

  A connector 7 connected to an external connector is provided on the back side of the printed wiring board 2 (attachment side to the case 4). In the printed wiring board 2, screw receiving holes 9 for inserting mounting screws 8 to the case 4 are formed at four corners, and positioning holes 10 are formed in the vicinity of the two screw receiving holes 9.

  In the printed wiring board 2, a positioning pin 11 provided in the case 4 is inserted into the positioning hole 10 to determine a mounting position with respect to the case 4.

  The printed wiring board 2 positioned by the positioning holes 10 and the positioning pins 11 is placed on the board fixing part 13 provided in the case 4 and fixed on the board fixing part 13 by the mounting screws 8.

Next, Case 4 will be described.
The case 4 is formed in a substantially rectangular bottomed box-like body that opens upward. The case 4 is formed of a metal material such as aluminum, iron, and stainless steel that has excellent heat dissipation properties in order to dissipate heat generated in the electric circuit portion to the outside.

  A connector projection hole 12 for projecting the connection portion of the connector 7 to the outside of the case 4 is formed in the bottom portion 4 a of the case 4.

  Substrate fixing portions 13 on which the printed wiring board 2 is placed are provided at the four corners in the case 4 and the central portion in the case longitudinal direction opposite to the connector protruding holes 12. A screw screw hole 14 is formed on the top surface of the board fixing portion 13, and as described above, the printed wiring board 2 is placed on the board fixing portion 13 and is attached to the board fixing portion 13 by the mounting screw 8. Fixed on top.

  A heat radiating base 15 for radiating the heat generated in the electronic component 6 to the outside of the case 4 is provided on the bottom 4 a of the case 4. The heat radiating base 15 is disposed in the vicinity of an electronic component that generates a large amount of heat among the electronic components 6 mounted on the printed wiring board 2. A heat dissipating material 16 is attached to a position on the upper surface of the heat dissipating pedestal 15 corresponding to the electronic component that generates a large amount of heat. Further, a protrusion 17 is provided on the upper surface of the radiating base 15, and the protrusion 17 prevents the case 4 and the wiring circuit pattern of the printed wiring board 2 from contacting each other. The case 4 is provided with heat radiating fins 18 for enhancing the cooling effect, and fixing brackets 19 and 20 for fixing the electronic control device 1 to the vehicle body.

  A first positioning mechanism 21 that restricts the mounting position of the cover 5 by sandwiching a first sandwiched portion (positioned portion) 31 of the cover 5, which will be described later, on the diagonal of the case 4, and the first of the cover 5 2 The 2nd positioning mechanism 22 which clamps the to-be-clamped part (positioned part) 32, and regulates the attachment position of the cover 5 is provided.

  As shown in FIG. 2, the first positioning mechanism 21 and the second positioning mechanism 22 (the second positioning mechanism 22 is not shown in FIG. 2) is composed of a pair of cover positioning pieces 23 and 24. The case 4 and the cover 5 are positioned by sandwiching a first sandwiched portion 31 of the cover 5 and a second sandwiched portion 32 of the cover 5 which will be described later with positioning pieces 23 and 24.

  As shown in FIG. 1, first screw screw holes 25 a to fourth screw screw holes 25 d for screwing the cover 5 to the case 4 are formed at the four corners of the case 4. The first screw screw hole 25 a is formed between the pair of cover positioning pieces 23 and 24 of the first positioning mechanism 21, and the third screw screw hole 25 c is a pair of cover positioning pieces 23 and 24 of the second positioning mechanism 22. 24 is formed. The second screw screw hole 25b is formed at a corner (corner) between the first screw screw hole 25a and the third screw screw hole 25c, and the fourth screw screw hole 25d is a third screw screw hole 25d. It is formed at a corner (corner) between the screw hole 25c and the first screw screw hole 25a. In addition, a seal groove 26 that seals between the cover 5 and the case 4 described below and injects a sealing material for bonding and fixing the both covers the entire outer periphery of the opening of the case 4. Is formed.

  The first positioning mechanism 21 and the second positioning mechanism 22 are configured such that the first sandwiched portion 31 and the second sandwiched portion 32 are fitted between a pair of cover positioning pieces 23 and 24, whereby the case 4 The positions of the first screw screw hole 25a to the fourth screw screw hole 25d formed in the first screw screw hole 25d and the first screw screw hole 35a to the fourth screw screw hole 35d formed in the cover 5, which will be described later, are aligned, and the seal groove 26 And the position of the annular ridge 33 formed on the cover 5 to be described later is aligned, and the insertion of the annular ridge 33 into the center of the seal groove 26 in the width direction is guided.

  The first positioning mechanism 21 and the second positioning mechanism 22 regulate the amount of positional deviation between the case 4 and the cover 5, and the annular protrusion 33 is largely displaced in the width direction within the seal groove 26, so that the inside of the seal groove 26 The seal material injected into the seal groove 33 is pushed out of the seal groove 26 by the annular ridge 33, resulting in uneven distribution of the seal material in the seal groove 26, and the sealing effect and adhesive effect of the seal material are reduced. To be prevented.

Next, the cover 5 will be described.
As shown in FIGS. 1, 3, 4, etc., the cover 5 is formed in a flat plate shape having a rectangular shape in a plan view using a metal material such as aluminum, iron, and stainless steel having excellent heat dissipation, as with the case 4. Yes. The cover 5 is attached to the case 4 so as to cover the printed wiring board 2 fixed to the case 4.

  The cover 5 is formed with a filter mounting hole 28 for attaching a breathing filter (pressure adjusting filter) 27 for adjusting the pressure in the case 4. A protective wall 29 that prevents water from entering the case 4 is provided around the filter mounting hole 28.

  Further, on the diagonal of the cover 5, a pair of the first positioning portion 31 positioned between the pair of cover positioning pieces 23 and 24 of the first positioning mechanism 21 and the pair of the second positioning mechanism 22 are positioned. A second sandwiched portion 32 that is sandwiched and positioned between the cover positioning pieces 23 and 24 is provided.

  At the peripheral edge of the bottom surface (the surface facing the case 4) of the cover 5, an annular ridge 33 is formed that is inserted into a seal groove 26 formed in the case 4 together with a sealant (not shown) such as an adhesive. ing. Further, shaft portions of fixing screws 34 for fastening and fixing the cover 5 to the case 4 are inserted at the four corners of the cover 5 and at positions facing the first screw screw hole 25a to the fourth screw screw hole 25d. A first screw insertion hole 35a to a fourth screw insertion hole 35d are formed.

  As shown in FIG. 5, the first screw insertion hole 35a is slightly larger in diameter than the first screw screw hole 25a formed in the case 4 (the first positioning mechanism 21 and the second positioning mechanism 22). When the cover 5 is overlaid on the case 4, the first positioning mechanism 21, the second positioning mechanism 22, the first sandwiched portion 31, and the second sandwiched portion are formed. The case 4 and the cover 5 are positioned by 32, and the first screw insertion hole 35a and the first screw screwing hole 25a are completely overlapped (overlapped state).

  The second screw insertion hole 35b to the fourth screw insertion hole 35d with respect to the first screw screw hole 25a take into account the accompanying rotation of the cover 5 that occurs when the screw is first screwed, as shown in FIG. It is formed in the shape and size. FIG. 6 illustrates the third screw insertion hole 35c as an example, representing the second screw insertion hole 35b to the fourth screw insertion hole 35d.

  Specifically, as shown in FIG. 3, the second screw insertion hole 35b has a radius R1 centered on the shaft portion of a fixing screw 34 (not shown) screwed into the first screw screw hole 25a. The second screw insertion hole 35b and the second screw threading hole are formed in consideration of the amount of movement of the cover 5 in the direction L1 (tightening direction of the fixing screw 34), and the cover 5 is rotated. The 25b overlaps each other completely.

  The third screw insertion hole 35c is formed in consideration of the amount of movement of the cover 5 in the circumferential direction L2 having a radius R2 centered on the shaft portion of the fixing screw 34 screwed into the first screw screwing hole 25a. Even when the cover 5 is rotated, the third screw insertion hole 35c and the third screw screw hole 25c completely overlap each other. Similarly, the fourth screw insertion hole 35d takes into account the amount of movement of the cover 5 in the circumferential direction L3 with a radius R3 centered on the shaft portion of the fixing screw 34 screwed into the first screw screw hole 25a. Even when the cover 5 is rotated, the fourth screw insertion hole 35d and the fourth screw screwing hole 25d are completely overlapped with each other.

  As shown in FIG. 6, the width W1 of the second screw insertion hole 35b to the fourth screw insertion hole 35d other than the rotation direction is formed to be substantially the same as the diameter of the first screw insertion hole 35a. The width W2 in the direction is widened in consideration of the amount of rotation of the cover 5.

  Therefore, even when the cover 5 is rotated, the peripheral surface of the shaft portion of the fixing screw 34 screwed into the second screw screw hole 25b to the fourth screw screw hole 25d and the second screw insertion hole 35b to the second screw screw hole 25b. As shown in FIG. 7, the clearance C with the inner peripheral surface of the four-screw insertion hole 35 d is generated only in the accompanying direction of the cover 5, and the generation of the clearance C other than the accompanying direction is suppressed. This suppresses a decrease in the tightening force of the cover 5 by the head 34a of the fixing screw 34 indicated by a two-dot chain line.

Next, the assembly procedure and effects of the electronic control device 1 will be described.
First, the heat dissipation material 16 is attached to the heat transfer surface on the upper surface of the heat dissipation base 15. Next, a sealing material is injected into the sealing groove 26 of the case 4. Next, after attaching the printed wiring board 2 to the case 4, the cover 5 is attached to the case 4. When attaching the cover 5 to the case 4, the first sandwiched portion 31 and the second sandwiched portion 32 provided on the cover 5 are connected to the first positioning mechanism 21 and the second positioning mechanism 22 provided on the case 4. It is inserted between the pair of cover positioning pieces 23, 24. As a result, the first screw insertion hole 35a to the fourth screw insertion hole 35d provided in the cover 5 are superimposed on the first screw engagement hole 25a to the fourth screw engagement hole 25d provided in the case 4, and the case 4 and the cover 5 are positioned, and the annular protrusion 33 provided in the cover 5 is inserted into the seal groove 26 provided in the case 4.

  Then, fixing screws 34 are screwed in the order of the first screw screw hole 25 a to the fourth screw screw hole 25 d, and the cover 5 is attached and fixed to the case 4 with these fixing screws 34.

  Even when the cover 5 is rotated when the cover 5 is tightened by the fixing screw 34 screwed into the first screw screw hole 25a, the second screw insertion hole 35b to the fourth screw insertion hole 35d Since the second screw screw hole 25b to the fourth screw screw hole 25d are maintained in an overlapping state, the fixing screw 34 to the second and subsequent second screw screw holes 25b to the fourth screw screw hole 25d is maintained. Can be reliably screwed.

  In the embodiment, the pair of cover positioning pieces 23 and 24 constituting the first positioning mechanism 21 among the four screw screw holes of the first screw screw hole 25a to the fourth screw screw hole 25d. The fixing screw 34 is first screwed into the first screw screw hole 25a provided between the other screw screw holes, for example, a pair of cover positioning pieces 23 constituting the second positioning mechanism 22, The fixing screw 34 may be first screwed into the third screw screw hole 25 c provided between the two screws 24. In this case, the third screw insertion hole 35c of the cover 5 facing the third screw screw hole 25c into which the fixing screw 34 is screwed first is inserted into the third screw screw hole into which the fixing screw 34 is screwed first. The other screw insertion hole is formed in consideration of the accompanying rotation of the cover 5 by the fixing screw 34 in the third screw screwing hole 25c. In the above embodiment, the case 4 and the cover 5 are screwed at four locations. However, this is because the shapes of the case 4 and the cover 5 are taken into consideration. In the case of a square, five points may be screwed. The location and number of screws are determined as appropriate depending on the size and shape of the case 4 and the cover 5. Moreover, in the said embodiment, the case where two members, the case 4 and the cover 5, are combined to form a casing, may be formed by combining three or more members.

DESCRIPTION OF SYMBOLS 1 ... Electronic control apparatus 2 ... Printed wiring board 3 ... Case 4 ... Member (case) which comprises a case
5 ... Members constituting the casing (cover)
21, 22 ... first and second positioning mechanisms 25 a to 25 d ... first to fourth screw screw holes 34 ... fixing screws 35 a to 35 d ... first to fourth screw insertion holes

Claims (3)

The housing for housing the circuit board on which the electronic component is mounted is composed of at least two members, one of which is provided with a plurality of screw screw holes for screwing the fixing screw, and the other member is provided with the shaft of the fixing screw. A plurality of screw insertion holes through which the portion is inserted are provided to face the plurality of screw screw holes, and a shaft portion of the fixing screw is screwed into the screw screw hole through the screw insertion hole. In an electronic control device for fastening and fixing the member with a fixing screw of
The other screw insertion holes are formed with a larger clearance than the other directions in the follow-up direction of the first fixing screw that is screwed into the screw insertion hole through which the fixing screw for initial tightening is inserted. Electronic control unit. 2. The electronic control device according to claim 1, wherein the casing includes a positioning mechanism that positions the members relative to each other, and the clearance is set within an allowable error of the positioning mechanism. The electronic control device according to claim 1, wherein the clearance is set according to a moving amount of the screw insertion hole with respect to the screw screw hole.

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