JP6991019B2 - Vehicle control unit - Google Patents

Description

The present invention relates to a vehicle control unit including a circuit board on which a control circuit is mounted and a case for accommodating the circuit board.

Automobiles and other vehicles are equipped with a large number of systems and devices and control units for controlling these systems and devices. A general automobile is equipped with, for example, a control unit that individually controls various systems such as a brake system, a car navigation system, and a power window system, and a control unit that comprehensively controls a plurality of systems and devices. There is. Further, in addition to the above-mentioned system and control unit, the special vehicle is equipped with a system and a device necessary for realizing the required functions and a control unit for controlling the system and the device.

Usually, a control unit as described above mounted on a vehicle includes a circuit board on which a control circuit is mounted and a case for accommodating the circuit board (Patent Document 1). The case of the control unit is composed of, for example, a case body provided with an opening for inserting and removing a circuit board, and a cover for closing the opening of the case body. Such a case body or cover is generally molded by injecting a resin material into a mold.

In many cases, the shape of the opening of the case body is designed to be square. However, it is difficult to form the opening of the case body, which is a resin molded product, into a perfect quadrangle. Specifically, the shape of the opening of the case body is a perfect quadrangle in design, but it is difficult to make a perfect quadrangle due to the influence of thermal expansion and heat shrinkage during and after molding. In other words, the opening is surrounded by four sides, but not all of these four sides are straight lines. Also, the opening has four vertices, but the internal angles of these four vertices are not right angles.

More specifically, the rectangular opening has a pair of opposing sides and another pair of opposing sides. In this case, each side may bend in a bow toward the inside of the opening. Such curvature of each side is called "inward warp". In addition, it may be called "inward warp" to refer to the state of an opening in which any side is curved inward in a bow shape. On the other hand, the side surrounding the opening may be curved in a bow shape toward the outside of the opening. Such edge curvature is called "outward warp" as opposed to "inward warp". In addition, the state of an opening in which any side is curved in a bow shape toward the outside may be referred to as "outward warp". In the present specification, the terms "inward warp" and "outward warp" are used according to such usage.

Here, in the case of a rectangle having a pair of short sides facing each other and a pair of long sides facing each other, the long side tends to have an inward warp more easily than the short side. That is, inward warpage tends to occur more easily in the rectangular opening than in the square opening.

Japanese Unexamined Patent Publication No. 2006-105049

On the other hand, the cover, which is smaller than the case body and does not have a large opening, is less affected by thermal expansion and contraction during and after molding compared to the case body, and is molded into the shape as designed. easy. Therefore, conventionally, a cover is fitted into the opening of the case body to close the opening and correct the inward warp of the opening.

However, eccentric warpage may occur in the opening of the case body in which the inward warp is corrected by the cover. For example, after a thermal shock test in which the case of the control unit is repeatedly exposed to a high temperature state and a low temperature state, eccentric warpage may occur in the opening of the case body.

As a result of diligent research on the cause of the occurrence of valgus, the inventors of the present invention have generated stress (stress) in and around the opening of the case body in which the deformation (inward warp) is corrected by the cover. It was found that is one of the causes of ex post facto warpage.

Annealing is one of the methods for preventing the case body from warping inward or outward. However, the implementation of the annealing process increases the number of manufacturing steps of the control unit including the molding of the case body, and raises the manufacturing cost.

The present invention has been made based on the above findings, and an object of the present invention is to provide a vehicle control unit in which the case is not deformed by a temperature change.

The vehicle control unit of the present invention is a polyhedron formed of a resin material, and is fitted into a case body having an opening on one surface, a circuit board housed in the case body, and the opening. It has a cover that closes the opening. The cover includes a first end face facing the first side of the opening and a second end face facing the second side facing the first side of the opening. Further, the first end surface and the second end surface are curved so that their respective intermediate portions in the longitudinal direction are closest to each other in the opposite direction between the first side and the second side.

In one aspect of the present invention, the opening of the case body is a substantially rectangular shape having the first side as one long side and the second side as the other long side.

In another aspect of the present invention, the case body is a hexahedron composed of an upper surface and a lower surface facing each other and four side surfaces adjacent to the upper surface and the lower surface, respectively, and is one of the four side surfaces. Is provided with the opening.

According to the present invention, a vehicle control unit in which the case is not deformed by a temperature change is realized.

It is a perspective view of the control unit for a vehicle to which this invention is applied. It is an exploded perspective view of the control unit for a vehicle shown in FIG. It is an enlarged perspective view of the cover shown in FIG. It is an enlarged plan view of the cover shown in FIG. It is explanatory drawing which shows the end face shape of the cover shown in FIG.

Hereinafter, an example of an embodiment of the vehicle control unit (hereinafter abbreviated as “control unit”) of the present invention will be described.

As shown in FIGS. 1 and 2, the control unit 1 has a case 2 and a circuit board 3 housed in the case 2. The case 2 is composed of a polyhedral case body 10 and a cover 30 that closes an opening 11 provided on one surface of the case body 10. Although not shown, the circuit board 3 shown in FIG. 2 is equipped with a control circuit for individually controlling various systems mounted on the vehicle. Further, the circuit board 3 has a female connector 3a (FIG. 1) to which a male connector provided at the end of a cable for transmitting an electric signal input / output to a control circuit is connected (inserted). It is provided. In FIG. 2, the connector 3a is not shown.

The case body 10 and the cover 30 are injection-molded with PBT resin (polybutylene terephthalate resin), which is a kind of resin material. The PBT resin, which is the material of the case body 10 and the cover 30 in the present embodiment, contains glass fiber.

As shown, the case body 10 is a polyhedron. Specifically, the case body 10 is a hexahedron composed of an upper surface 12 and a lower surface 13 facing each other and four side surfaces 14, 15, 16 and 17 adjacent to the upper surface 12 and the lower surface 13. The areas of the upper surface 12 and the lower surface 13 are the same, and are the largest of the six surfaces. Further, the opening 11 is provided on the side surface 14. In the following description, the side surface 14 provided with the opening 11 is referred to as a "front surface 14", and the side surface 15 facing the front surface 14 is referred to as a "rear surface 15". Further, of the two side surfaces 16 and 17 adjacent to the front surface 14 and the back surface 15, one side surface 16 is referred to as a “left side surface 16” and the other side surface 17 is referred to as a “right side surface 17”. However, the distinction by the above names is merely a distinction for convenience of explanation.

As shown in FIG. 2, the opening 11 is a substantially quadrangle surrounded by the opposing first side 11a and second side 11b, and the opposing third side 11c and fourth side 11d. be. More specifically, the opening 11 is substantially rectangular, the first side 11a is one of the long sides, and the second side 11b is the other one of the long sides. Further, the third side 11c is one of the short sides, and the fourth side 11d is the other one of the short sides. That is, the opening 11 is a substantially rectangular shape surrounded by a pair of long sides 11a and 11b facing each other and a pair of short sides 11c and 11d facing each other.

The cover 30, which constitutes the case 2 together with the case body 10, is fitted inside the opening 11 of the case body 10 after the circuit board 3 is housed in the case body 10. Therefore, the cover 30 has a shape (outer shape) corresponding to the shape of the opening 11. The cover 30 is enlarged and shown in FIGS. 3 and 4. The cover 30 has a substantially rectangular main surface 31 that covers the opening 11 (FIG. 2), and four end faces 32 that extend from each side of the main surface 31 in a direction orthogonal to the main surface 31.

A window 33 is provided on the main surface 31 of the cover 30 at a position corresponding to the connector 3a (FIG. 2). As shown in FIGS. 1 and 2, when the cover 30 is fitted into the opening 11 of the case body 10 in which the circuit board 3 is housed, a part of the connector 3a provided on the circuit board 3 passes through the window 33. Protruding to the outside.

Refer to FIGS. 3 and 4 again. One long side of the main surface 31 of the cover 30 is provided with a first end surface 32a connected to the first end surface 32a, and the other long side is provided with a second end surface 32b connected to the first end surface 32a. Further, one short side of the main surface 31 is provided with a third end surface 32c connected to the third end surface 32c, and the other short side is provided with a fourth end surface 32d connected to the third end surface 32c.

As can be understood from FIGS. 1 and 2, when the cover 30 is attached to the case body 10, each end surface 32 of the cover 30 is inserted into the inside of the case body 10 through the opening 11. Specifically, the first end surface 32a of the cover 30 is inserted inside the upper surface of the case body 10. Similarly, the second end surface 32b is inserted inside the lower surface, the third end surface 32c is inserted inside the left side surface, and the fourth end surface 32d is inserted inside the right side surface. Therefore, in the following description, the first end surface 32a of the cover 30 is the "upper end surface 32a", the second end surface 32b is the "lower end surface 32b", the third end surface 32c is the "left end surface 32c", and the fourth end surface 32d is ". It may be called "right end face 32d" to distinguish it. However, such a distinction is merely a distinction for convenience of explanation.

When the cover 30 is fitted into the opening 11 as described above, the upper end surface 32a of the cover 30 faces the long side 11a of the opening 11. Further, the lower end surface 32b of the cover 30 faces the long side 11b of the opening 11, the left end surface 32c of the cover 30 faces the short side 11c of the opening 11, and the right end surface 32d of the cover 30 faces the opening 11. It faces the short side 11d.

Here, as shown in FIG. 5, the upper end surface 32a and the lower end surface 32b of the cover 30 are not flat, but are curved inward in an arcuate manner. Specifically, the upper end surface 32a and the lower end surface 32b are curved so that their respective intermediate portions in the longitudinal direction are closest to each other in the opposite directions of the long sides 11a and 11b (FIG. 2) of the opening 11. ..

In the following description, the straight line X shown in FIG. 5 is defined as the first reference line, and the straight line Y is defined as the second reference line. The straight line X, which is the first reference line, is a straight line connecting both ends in the longitudinal direction of the upper end surface 32a, and the straight line Y, which is the second reference line, is a straight line connecting both ends in the longitudinal direction of the lower end surface 32b. As shown, the upper end surface 32a of the cover 30 is curved so that the central portion in the longitudinal direction thereof is most distant from the first reference line and both ends in the longitudinal direction thereof are closest to the first reference line. .. Further, the lower end surface 32b of the cover 30 is curved so that the central portion in the longitudinal direction thereof is most distant from the second reference line and both ends thereof in the longitudinal direction are closest to the second reference line. In other words, there is a gap between the first reference line and the upper end surface 32a, and this gap becomes maximum in the central portion in the longitudinal direction of the upper end surface 32a (hereinafter referred to as "the central portion of the upper end surface"). , It is the minimum at both ends in the longitudinal direction of the upper end face 32a (hereinafter referred to as "both ends of the upper end face"). Similarly, there is a gap between the second reference line and the lower end surface 32b, and this gap is the central portion in the longitudinal direction of the lower end surface 32b (hereinafter referred to as "the central portion of the lower end surface"). Is the maximum, and is the minimum at both ends in the longitudinal direction of the lower end surface 32b (hereinafter referred to as "both ends of the lower end surface").

In the present embodiment, the separation distance (D1) of the central portion of the upper end surface with respect to the first reference line and the separation distance (D2) of the central portion of the lower end surface with respect to the second reference line are 1 mm, respectively. That is, the maximum gap between the first reference line and the upper end surface 32a is 1 mm, and the maximum gap between the second reference line and the lower end surface 32b is also 1 mm.

The length (L) of the cover 30 shown in FIG. 5 is 144 mm, the width (W1) is 30 mm, and the width (W2) of the window 33 is 24 mm.

As described above, the upper end surface 32a and the lower end surface 32b of the cover 30 are curved inward, respectively. Therefore, even if the cover 30 is fitted inside the inwardly warped opening 11, the inward warp of the opening 11 is not corrected, but there is a gap between the upper end surface 32a of the cover 30 and the long side 11a of the opening 11. Also, there is no gap between the lower end surface 32b of the cover 30 and the long side 11b of the opening 11. That is, the upper end surface 32a and the lower end surface 32b of the cover 30 are curved so as to follow the inwardly curved long sides 11a and 11b of the opening 11.

As described above, the case 2 of the control unit 1 according to the present embodiment is composed of a case main body 10 provided with an opening 11 and a cover 30 fitted in the opening 11. The upper end surface 32a and the lower end surface 32b of the cover 30 are curved so as to follow the long sides 11a and 11b of the inwardly curved opening 11. In other words, the inward warp of the opening 11 is absorbed by the curved upper end surface 32a and the lower end surface 32b of the cover 30. Therefore, stress is not applied to the opening 11 of the case body 10 and its surroundings, or even if stress is applied, the stress is very small, so that the opening 11 may be warped due to a temperature change. do not have.

The inventors of the present invention conducted a thermal shock test on the case 2 (not annealed) constituting the control unit 1 according to the present embodiment, and confirmed that the opening 11 of the case body 10 did not warp. ing. In this test, case 2 was left in an environment of −40 ° C. for 1 hour, then moved to an environment of + 80 ° C. within a few minutes and left for 1 hour as one cycle, and this was repeated for 1000 cycles.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist thereof. For example, the material of the case body 10 and the cover 30 is not limited to the above resin material (PBT resin). Further, different materials can be used for the case body 10 and the cover 30. The degree of curvature of the upper end surface 32a and the lower end surface 32b of the cover 30 can be appropriately changed. Specifically, the separation distances D1 and D2 shown in FIG. 5 can be appropriately changed. However, the cover 30 does not correct the inward warp of the opening 11 of the case body 10. Therefore, the expansion of the separation distances D1 and D2 shown in FIG. 5 means that the width of the opening 11 and its vicinity after the cover 30 is fitted is narrowed. In other words, it means that the height of the internal space of the case body 10 after the cover 30 is attached becomes low. Therefore, when determining the separation distances D1 and D2, it is preferable to consider the clearance required between the inner surface of the case body 10 and the circuit board 3 housed in the case body 10.

The present invention is not intended only for a control unit for controlling a specific system or device, but is intended for almost all control units mounted on a vehicle.

1 Vehicle control unit (control unit)
2 Case 3 Circuit board 3a Connector 10 Case body 11 Opening 11a First side (long side)
11b Second side (long side)
11c Third side (short side)
11d 4th side (short side)
12 Top surface 13 Bottom surface 14 Side surface (front surface)
15 Side (back)
16 Side (left side)
17 Side (right side)
30 Cover 31 Main surface 32 End surface 32a First end surface (upper end surface)
32b 2nd end face (lower end face)
32c 3rd end face (left end face)
32d 4th end face (right end face)
33 Window D1, D2 Separation distance

Claims (2)

A case body that is a polyhedron formed of a resin material and has a substantially rectangular opening on one side.
The circuit board housed in the case body and
A vehicle control unit having a cover that is fitted into the opening and closes the opening.
The cover is provided with a plate-shaped portion forming a main surface covering the opening, and a first end surface facing the first long side of the opening and connected to one long side of the main surface. A plate-shaped portion forming an end surface on the back side of the first end surface and a second long side which is provided in contact with the other long side of the main surface and faces the first long side of the opening. A plate-shaped portion forming an opposing second end surface and an end surface on the back side of the second end surface, and a second end surface that is connected to one short side of the main surface and faces the first short side of the opening. A second short side facing the first short side of the opening, which is provided in contact with the other short side of the main surface and the plate-shaped portion forming the three end faces and the end face on the back side of the third end face. It is a resin member integrally molded with a fourth end face facing the short side and a plate-shaped portion forming the end face on the back side of the fourth end face .
The first end face, the second end face, the third end face, and the fourth end face are inserted inside the opening.
The first end face and the second end face are curved so that the distance between the intermediate portions in the longitudinal direction is closest to each other in the opposite direction between the first long side and the second long side .
Vehicle control unit. In the vehicle control unit according to claim 1 ,
The case body is a hexahedron composed of upper and lower surfaces facing each other and four side surfaces adjacent to the upper and lower surfaces, respectively.
The opening is provided on one of the four side surfaces.
Vehicle control unit.

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