JP5875724B1 - control unit - Google Patents

Abstract

A control unit capable of suppressing a reduction in mounting efficiency of components on a board is obtained. A control unit includes a board and a relay mounted on the board. The relay 3 includes a case 31 having a case opening, a relay main body housed in the case 31, a base 32 that fits on the inner peripheral surface of the case 31 and closes the case opening, and an inner periphery of the case 31. And a sealing material 33 for sealing a gap between the surface and the base 32. The relay 3 is arranged with the case opening facing the substrate 2. A through hole 5 is provided in the substrate 2. The opening end of the through hole 5 on the relay 3 side faces the boundary between the case 31 and the sealing material 33. [Selection] Figure 2

Description

  The present invention relates to a control unit in which a relay is mounted on a substrate.

  2. Description of the Related Art Conventionally, a sealed relay in which a cover is press-fitted into an opening of a case that houses a relay main body and a gap between the case and the cover is sealed with a sealing material is known. Conventionally, as a method of mounting a component on a substrate with solder, a solder reflow method is known in which the component is placed on paste solder applied to the substrate and the substrate is heated together with the component to melt the solder.

  When a sealed relay is mounted on a substrate by a solder reflow method, the gas in the case expands because the relay is placed in a high temperature environment. When the pressure in the case exceeds the allowable value for sealing the sealing material due to the expansion of the gas in the case, the gas in the case breaks the sealing material and blows out of the case.

  Conventionally, the relay case is provided with a groove, and the sealing material is filled in the groove of the case to make it difficult to remove the sealing material from the case, thereby improving the reliability of the sealed state between the case and the cover. Have been proposed (see, for example, Patent Document 1).

JP 2007-294371 A

  In recent years, there has been an increasing demand for lead-free solder as a solder used in the solder reflow method from the environmental aspect. When lead-free solder is used, the heating temperature when the component is mounted on the board increases. Therefore, even in the conventional sealed relay disclosed in Patent Document 1, the inside of the case when mounted on the board There is a risk that the pressure rise cannot be suppressed by the sealing material.

  If the gas in the case breaks the sealing material and blows out at a high pressure, the gas blown out from the case may hit the substrate and adversely affect, for example, damage or misalignment on the components around the relay. In the conventional hermetic relay disclosed in Patent Document 1, the pressure of the gas blown out from the inside of the case increases due to the improvement of the hermeticity of the case, so that the area where the mounting of parts around the relay is prohibited is widened. . Thereby, the mounting efficiency of the component with respect to a board | substrate will fall.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a control unit capable of preventing a reduction in mounting efficiency of components on a board.

  A control unit according to the present invention includes a board and a relay mounted on the board, and the relay is fitted to a case having a case opening, a relay body housed in the case, and an inner peripheral surface of the case. A base that closes the case opening, and a sealing material that seals a gap between the inner peripheral surface of the case and the base, and the relay is disposed with the case opening facing the board. Is provided with a through hole, and the opening end of the through hole on the relay side faces the boundary between the case and the sealing material.

  The control unit according to the present invention includes a substrate, a relay mounted on the substrate, and a cover attached to the relay, and the relay includes a case having a case opening and a relay accommodated in the case. A main body, a base that fits on the inner peripheral surface of the case and closes the case opening, and a sealing material that seals a gap between the inner peripheral surface of the case and the base. The cover is attached to the case so as to cover the case opening, and the cover is provided with the cover opening. When viewed, it is within the region of the case opening, the substrate is provided with a through hole, and the opening end on the relay side of the through hole faces the cover opening.

  According to the control unit of the present invention, even when the gas blows out from the boundary between the case and the sealing material, the gas can be released to the opposite side of the substrate through the through hole. Thereby, the air volume of the gas blown out around the relay can be reduced, and the gas can be prevented from adversely affecting the components arranged around the relay. Therefore, it is possible to prevent the expansion of the component prohibited area around the relay, and to prevent the component mounting efficiency from being lowered on the board.

It is a typical perspective view which shows the principal part of the control unit by Embodiment 1 of this invention. It is a longitudinal cross-sectional view which shows the principal part of the relay of FIG. It is a perspective view which shows the board | substrate of FIG. It is a typical perspective view which shows the relay of the control unit by Embodiment 2 of this invention. It is a disassembled perspective view which shows the state which has removed the cover from the relay of FIG. It is a longitudinal cross-sectional view which shows the principal part of the relay and cover of FIG. It is a perspective view which shows the board | substrate with which the relay of FIG. 4 is mounted.

Embodiment 1 FIG.
FIG. 1 is a schematic perspective view showing a main part of a control unit according to Embodiment 1 of the present invention. The control unit 1 includes a substrate 2 and a mounting component group mounted on the substrate 2. The mounting component group includes a relay 3, a microcomputer, an electrolytic capacitor and the like as a plurality of surface mounting components, that is, SMD (Surface Mount Device).

  The substrate 2 has a first substrate surface 2a and a second substrate surface 2b facing each other. Each SMD including the relay 3 is mounted on the first substrate surface 2a and the second substrate surface 2b. A wiring pattern (not shown) is provided on the first substrate surface 2a and the second substrate surface 2b by printing. That is, the board 2 is a printed board. The wiring pattern includes a plurality of conductive pads 4. Each SMD including the relay 3 is mounted on the plurality of pads 4 via solder.

  FIG. 2 is a longitudinal sectional view showing a main part of the relay 3 of FIG. The relay 3 includes a case 31 having a case opening, a relay main body (not shown) housed in the case 31, a base 32 that fits on the inner peripheral surface of the case 31 and closes the case opening of the case 31, It has a sealing material 33 that seals the gap between the inner peripheral surface of the case 31 and the base 32. That is, the relay 3 is a sealed relay in which the relay body is accommodated in a sealed case 31.

  The case opening of the case 31 is formed by the inner peripheral surface of the case 31. In this example, the shape of the case opening is rectangular. The base 32 is molded according to the shape of the case opening. Therefore, in this example, the shape of the base 32 is also rectangular.

  The relay main body includes a relay coil, a relay contact portion that opens and closes a contact by executing and stopping power supply to the relay coil, and a plurality of relay connection terminals 34 that are electrically connected to the relay contact portion. ing. The relay coil and the relay contact portion are accommodated in the case 31. The base 32 is provided with a plurality of terminal holes (not shown) through which the relay connection terminals 34 are individually passed. Each relay connection terminal 34 protrudes from the case 31 through the terminal hole of the base 32 to the outside of the case 31. A gap between each relay connection terminal 34 and the base 32 is sealed with a sealing material 33. In this example, four relay connection terminals 34 protrude from the inside of the case 31 to the outside of the case 31. In this example, the protruding end of each relay connection terminal 34 is bent in parallel with the base 32.

  The relay 3 is arranged with the case opening of the case 31 facing the substrate 2. Each pad 4 is provided with a protruding end portion of each relay connection terminal 34 individually. Each relay connection terminal 34 is mechanically and electrically connected to the pad 4 by solder. The case 31, the base 32, and the sealing material 33 are supported by each relay connection terminal 34. As a result, the case 31, the base 32, and the sealing material 33 are disposed between the substrate 2 and the space.

  The sealing material 33 is filled in the case opening of the case 31 so as to overlap the base 32. Thereby, the sealing material 33 is bonded to each of the case 31 and the base 32. A portion of the inner peripheral surface of the case 31 to which the sealing material 33 is bonded is a case bonding surface 31a. Therefore, the case bonding surface 31 a is located at the boundary between the case 31 and the sealing material 33. In the relay 3, the sealing material 33 is interposed in the gap between the case bonding surface 31 a and the base 32, so that the gap between the case 31 and the base 32 is sealed. As the sealing material 33, for example, an adhesive made of an epoxy resin is used. The sealing material 33 injects a fluid material made of, for example, an epoxy resin onto the base 32 fitted in the case opening of the case 31, and solidifies the fluid material injected onto the base 32. It is formed by.

  FIG. 3 is a perspective view showing the substrate 2 of FIG. The substrate 2 is provided with a plurality of through holes 5 that reach from the first substrate surface 2a to the second substrate surface 2b. In this example, each through hole 5 is a round hole having a circular cross section. Each through-hole 5 has a first opening end formed on the first substrate surface 2a and a second opening end formed on the second substrate surface 2b. Therefore, the first opening end is located on the relay 3 side of the through hole 5, and the second opening end is located on the opposite side of the through hole 5 from the relay 3 side. Each first opening end of each through-hole 5 is on an intersection line 6 between the virtual extension surface and the first substrate surface 2a when the boundary between the case 31 and the sealing material 33 extends toward the substrate 2. Is located. Thereby, each first opening end of each through hole 5 faces the boundary between the case 31 and the sealing material 33. In this example, when the board 2 and the relay 3 are viewed along the thickness direction of the board 2, the shape of the boundary line between the case 31 and the sealing material 33 is rectangular, and each of the through holes 5 has a rectangular shape. The first opening end is located on a rectangular boundary line between the case 31 and the sealing material 33. Further, in this example, each through hole 5 is provided in the substrate 2 along the thickness direction of the substrate 2.

  A conductive layer is provided on the inner surface of each through-hole 5 by, for example, metal plating. The conductive layer provided on the inner surface of the through hole 5 electrically connects the wiring pattern provided on the first substrate surface 2a and the wiring pattern provided on the second substrate surface 2b to each other. It is a through hole.

  Next, a method for manufacturing the control unit 1 will be described. First, a specific wiring pattern is provided on each of the first substrate surface 2 a and the second substrate surface 2 b by printing, and a plurality of through holes 5 are provided in the substrate 2. Further, a conductive layer is provided on the inner surface of each through hole 5 by, for example, metal plating.

  Thereafter, paste solder is applied to each pad 4 of the wiring pattern provided on each of the first substrate surface 2a and the second substrate surface 2b.

  Thereafter, each relay connection terminal 34 is placed on the solder paste applied to the plurality of pads 4 corresponding to the relay 3, and the relay 3 is placed on the pad 4. Also, other SMDs other than the relays 3 are placed on the pads 4 corresponding to the respective SMDs in the same manner as the relays 3.

  Then, the board | substrate 2 with which several SMD containing the relay 3 is mounted is put into a reflow furnace. In the reflow furnace, each SMD and the substrate 2 are heated to a specific peak temperature at which the solder applied to the pad 4 melts. For example, when the solder applied to the pad 4 is lead-free solder, each SMD and the substrate 2 are heated to a peak temperature of 260 ° C. Thereby, the paste-like solder applied to the pad 4 is melted, and each SMD is connected to the pad 4 by the solder. Therefore, each relay connection terminal 34 of the relay 3 that is an SMD is also connected to the pad 4 corresponding to the relay 3 by solder.

  When the relay 3 is heated in the reflow furnace and the gas in the case 31 of the relay 3 expands, the pressure in the case 31 increases. If the adhesive force of the sealing material 33 to the case adhesive surface 31a cannot withstand the pressure of the gas in the case 31 due to an increase in pressure in the case 31, the sealing material 33 is peeled off from the case adhesive surface 31a and The gas is blown out of the case 31. The gas in the case 31 blows out of the case 31 from a position where the adhesive force of the sealing material 33 to the case bonding surface 31 a is weakest in the boundary between the case 31 and the sealing material 33.

  The first opening end of each through-hole 5 faces the boundary between the case 31 and the sealing material 33. Therefore, at least a part of the gas blown out of the case 31 from the boundary between the case 31 and the sealing material 33 enters each through hole 5 from the first opening end portion, and then passes through each through hole 5 to the second. The through hole 5 exits from the open end of the. That is, at least a part of the gas blown out of the case 31 to the outside of the case 31 passes through the through holes 5 to the side opposite to the relay 3 side of the substrate 2. Thereby, on the 1st board | substrate surface 2a, the air volume of the gas which blows off around the relay 3 decreases, and it is avoided that other SMDs around the relay 3 are damaged or displaced. Further, since the gas that has passed through each through hole 5 is just blown out from each through hole as it is along each through hole 5, it is difficult for the gas to hit each SMD disposed on the second substrate surface 2b. It is also avoided that each SMD disposed on the second substrate surface 2b is damaged or displaced.

  Then, the board | substrate 2 with which each SMD was mounted is taken out from a reflow furnace, and is cooled. In this way, the control unit 1 is manufactured.

  In such a control unit 1, the substrate 2 is provided with the through hole 5, and the first opening end of the through hole 5 on the relay 3 side faces the boundary between the case 31 and the sealing material 33. Therefore, even if the gas in the case 31 is blown out from the boundary between the case 31 and the sealing material 33 due to the pressure increase in the case 31 of the relay 3, the gas blown out from the case 31 is passed through the through hole 5. It can escape to the opposite side of the substrate 2. Thereby, the air volume of the gas blown out around the relay 3 can be reduced, and the SMD arranged around the relay 3 is prevented from being damaged or displaced by the gas blown out from the case 31. be able to. Thereby, it is possible to prevent the SMD mounting prohibited area from expanding around the relay 3, and it is possible to prevent a reduction in the mounting efficiency of the SMD on the substrate 2 around the relay 3. In addition, since the gas passing through each through hole 5 is just blown out from each through hole as it is along each through hole 5, each SMD arranged on the second substrate surface 2b is damaged or displaced. This can also be prevented.

  In addition, since a conductive layer is provided on the inner surface of the through hole 5, the wiring patterns provided on the first and second substrate surfaces 2 a and 2 b different from each other on the substrate 2 are connected to each other through the conductive material of the through hole 5. The layers can be electrically connected, and the SMD mounting density can be further improved.

  In the above example, the plurality of through holes 5 facing the boundary between the case 31 and the sealing material 33 are round holes. However, the present invention is not limited to this, for example, the boundary between the case 31 and the sealing material 33. May be provided in the substrate 2 as a through hole 5, and the first opening end of the through hole 5 may be opposed to the boundary between the case 31 and the sealing material 33.

Embodiment 2. FIG.
FIG. 4 is a schematic perspective view showing a relay of a control unit according to Embodiment 2 of the present invention. A cover 7 is attached to the relay 3. The cover 7 is attached to the case 31 so as to cover the case opening of the case 31. The configuration of relay 3 is the same as that of relay 3 in the first embodiment.

  FIG. 5 is an exploded perspective view showing a state where the cover 7 is removed from the relay 3 of FIG. FIG. 6 is a longitudinal sectional view showing the main parts of the relay 3 and the cover 7 of FIG. The cover 7 includes a cover main body 71 that covers the case opening of the case 31 and a plurality of (two in this example) cover mounting portions 72 that protrude from the cover main body 71.

  The cover main body 71 includes a cover plate portion 711 facing the case opening of the case 31, and a cover frame portion 712 that is provided on the cover plate portion 711 and surrounds the outer periphery of the case 31 along the case bonding surface 31a. Yes. A portion of the case 31 that forms the case opening is fitted inside the cover frame portion 712.

  The cover plate portion 711 faces the seal material 33 with a gap. The cover plate 711 is provided with one cover opening 73 and a plurality (four in this example) of cover terminal holes 74.

  The cover opening 73 is an opening smaller than the case opening of the case 31. In this example, as shown in FIG. 5, the inner surface of the cover opening 73 is inclined in a direction in which the area of the cover opening 73 continuously increases toward the case 31. The cover opening 73 is within the region of the case opening when the case 31 is viewed from the cover 7 side. In this example, the cover opening 73 is provided at the center of the cover plate 711. Further, when the case 31 is viewed from the cover 7 side, the cover opening 73 is provided so as to avoid the boundary between the case 31 and the sealing material 33, that is, the position of the case bonding surface 31a. As a result, the cover plate portion 711 faces the boundary between the case 31 and the sealing material 33 on the substrate 2 side of the case 31.

  Each relay connection terminal 34 is individually passed through the cover terminal hole 74. The protruding end of each relay connection terminal 34 is bent in parallel with the base 32 as shown in FIG.

  Each cover attachment portion 72 protrudes from the cover frame portion 712. In this example, the cover attachment portions 72 are provided at positions of the cover frame portion 712 facing each other. Each cover mounting portion 72 is provided with an engagement hole 75 penetrating the cover mounting portion 72.

  On the outer surface of the case 31, a plurality of (in this example, two) protrusions 76 that are individually fitted in the respective engagement holes 75 are provided. As shown in FIG. 4, each protrusion 76 is fitted in each engagement hole 75 in a state where the cover main body 71 covers the case opening of the case 31. Each cover attachment portion 72 is engaged with the protrusion 76 by fitting the protrusion 76 into the engagement hole 75. The cover 7 is attached to the case 31 by the cover attachment portions 72 engaging the projections 76. Further, the cover 7 is detached from the case 31 when the engagement of each cover mounting portion 72 with respect to each projection 76 is released.

  FIG. 7 is a perspective view showing the substrate 2 on which the relay 3 of FIG. 4 is mounted. The board 2 is a printed board similar to that of the first embodiment. The relay 3 is arranged with the case opening of the case 31 facing the substrate 2. Each pad 4 corresponding to the relay 3 is individually provided with a protruding end portion of each relay connection terminal 34. Each relay connection terminal 34 is mechanically and electrically connected to the pad 4 by solder. The case 31, the base 32, the sealing material 33, and the cover 7 are supported by each relay connection terminal 34. As a result, the case 31, the base 32, the sealing material 33, and the cover 7 are disposed between the substrate 2 and the space.

  The substrate 2 is provided with a plurality of through holes 5 that reach from the first substrate surface 2a to the second substrate surface 2b. In this example, each through hole 5 is a round hole having a circular cross section. Each through-hole 5 has a first opening end formed on the first substrate surface 2a and a second opening end formed on the second substrate surface 2b. Therefore, the first opening end is located on the relay 3 side of the through hole 5, and the second opening end is located on the opposite side of the through hole 5 from the relay 3 side.

  Each first opening end of each through hole 5 faces the cover opening 73. Accordingly, the first opening end of each through hole 5 is located in the region 8 of the cover opening 73 when the substrate 2 and the cover 7 are viewed along the thickness direction of the substrate 2. In this example, when the substrate 2 and the cover 7 are viewed along the thickness direction of the substrate 2, the shape of the cover opening 73 is a rectangular shape, and each first opening end of each through-hole 5 is formed. Is located in the region 8 of the rectangular cover opening 73. Further, in this example, each through hole 5 is provided in the substrate 2 along the thickness direction of the substrate 2.

  A conductive layer is provided on the inner surface of each through-hole 5 by, for example, metal plating. The conductive layer provided on the inner surface of the through hole 5 electrically connects the wiring pattern provided on the first substrate surface 2a and the wiring pattern provided on the second substrate surface 2b to each other. It is a through hole. Other configurations are the same as those in the first embodiment.

  Next, a method for attaching the cover 7 to the relay 3 will be described. As shown in FIG. 5, each relay connection terminal 34 of the relay 3 is left protruding straight from the case 31 without being bent. When the cover 7 is attached to the relay 3, the relay connection terminals 34 are inserted into the cover terminal holes 74 of the cover 7, and in this state, the portion forming the case opening of the case 31 is placed inside the cover frame portion 712. Fit. As a result, the case opening of the case 31 is covered with the cover body 71.

  Thereafter, when the cover 7 is further pushed toward the case 31, each cover mounting portion 72 comes into contact with the projection 76 and is displaced while being elastically deformed, and each projection 76 fits into each engagement hole 75 individually. Thereby, each cover attaching part 72 is engaged with each protrusion 76, and the cover 7 is attached to the case 31. Thereafter, the protruding end portion of each relay connection terminal 34 is bent in parallel with the base 32, whereby the attachment of the cover 7 to the relay 3 is completed.

  The manufacturing method of the control unit is the same as that of the first embodiment. When the relay 3 is heated in the reflow furnace, the gas in the case 31 expands and the pressure in the case 31 increases. If the adhesive force of the sealing material 33 to the case bonding surface 31a cannot withstand the pressure of the gas in the case 31, the sealing material 33 is peeled off from the case bonding surface 31a as in the first embodiment, and the gas in the case 31 is removed. Will blow out of the case 31. The gas in the case 31 blows out of the case 31 from a position where the adhesive force of the sealing material 33 to the case bonding surface 31 a is weakest in the boundary between the case 31 and the sealing material 33.

  In this embodiment, since the cover 7 is attached to the relay 3, the gas blown out from the case 31 hits the cover plate portion 711 as shown by the arrow A in FIG. It is guided to the cover opening 73 through the gap between the plate portion 711 and flows from the cover opening 73 toward the substrate 2. After that, at least a part of the gas emitted from the cover opening 73 enters each through hole 5 from the first opening end, and then passes through each through hole 5 from the second opening end. Exit. That is, at least a part of the gas that has come out of the cover opening 73 passes through the through holes 5 to the side opposite to the relay 3 side of the substrate 2.

  Thereby, on the 1st board | substrate surface 2a, the air volume of the gas which blows off around the relay 3 decreases. Moreover, since the gas blown out from the case 31 hits the cover plate portion 711 or passes through the gap between the sealing material 33 and the cover plate portion 711 and receives resistance, the pressure of the gas emitted from the cover opening 73 Also decreases. This prevents other SMDs around the relay 3 from being damaged or displaced. Further, since the gas that has passed through each through hole 5 is just blown out from each through hole as it is along each through hole 5, it is difficult for the gas to hit each SMD disposed on the second substrate surface 2b. It is also avoided that each SMD disposed on the second substrate surface 2b is damaged or displaced.

  In such a control unit, the cover opening 73 provided in the cover 7 is within the region of the case opening when the case 31 is viewed from the cover 7 side. Since the first opening end of the through hole 5 on the relay 3 side faces the cover opening 73, the gas blown from the boundary between the case 31 and the sealing material 33 can be guided to the cover opening 73. The gas emitted from the cover opening 73 can escape to the opposite side of the substrate 2 through the through hole 5. Further, the pressure of the gas can be reduced by applying the gas blown from the boundary between the case 31 and the sealing material 33 to the cover 7 or passing it through the gap between the cover 7 and the relay 3. Thereby, the air volume and the wind speed of the gas blown out around the relay 3 can be reduced, and the SMD arranged around the relay 3 is damaged or displaced by the gas blown out from the case 31. Furthermore, it can prevent reliably. Thereby, it is possible to prevent the SMD mounting prohibited area from spreading around the relay 3, and it is possible to more reliably prevent the SMD mounting efficiency from being lowered on the board 2 around the relay 3. In addition, since the gas passing through each through hole 5 is just blown out from each through hole as it is along each through hole 5, each SMD arranged on the second substrate surface 2b is damaged or displaced. This can also be prevented.

  The inner surface of each cover terminal hole 74 may be inclined in a direction approaching the cover opening 73 from the case 31 side toward the substrate 2 side. If it does in this way, the gas which leaked from each cover terminal hole 74 can be flowed toward the 1st opening end part of each through-hole 5, and it will have a bad influence on SMD arrange | positioned around the relay 3 This can be prevented more reliably.

  In the above example, the number of cover openings 73 provided in the cover plate portion 711 is one. However, the present invention is not limited to this, and a plurality of cover opening portions 73 may be provided in the cover plate portion 711. Good. In this case, the first opening end of each through hole 5 faces one of the cover openings 73.

  In the above example, the cover 7 is attached to the case 31 by the two cover attaching portions 72 provided on the cover main body 71, but the number of the cover attaching portions 72 is not limited to this, and the cover main body 71 includes Three or more cover attaching portions 72 may be provided, and the cover 7 may be attached to the case 31 by three or more cover attaching portions 72. In this case, the case 31 is provided with three or more projections 76 with which the cover mounting portion 72 is engaged, corresponding to each cover mounting portion 72.

  Moreover, in each said embodiment, although the conductive layer is provided in the inner surface of each through-hole 5, a conductive layer does not need to be provided. Even if there is no conductive layer on the inner surface of each through-hole 5, the gas blown out from the case 31 can be passed through each through-hole 5, thereby preventing adverse effects on the SMD around the relay 3. it can.

  1 controller unit, 2 substrate, 3 relay, 5 through-hole, 7 cover, 31 case, 32 base, 33 sealing material, 73 cover opening.

Claims (3)

A board, and a relay mounted on the board,
The relay includes a case having a case opening, a relay body housed in the case, a base that fits on an inner peripheral surface of the case and closes the case opening, and an inner peripheral surface of the case And a sealing material for sealing a gap between the base and the base,
The relay is arranged with the case opening facing the substrate,
The substrate is provided with a through hole,
An opening end portion of the through hole on the relay side is opposed to a boundary between the case and the sealing material. substrate,
A relay mounted on the board, and a cover attached to the relay;
The relay includes a case having a case opening, a relay body housed in the case, a base that fits on an inner peripheral surface of the case and closes the case opening, and an inner peripheral surface of the case And a sealing material for sealing a gap between the base and the base,
The relay is arranged with the case opening facing the substrate,
The cover is attached to the case in a state of covering the case opening,
The cover is provided with a cover opening,
The cover opening is within the region of the case opening when the case is viewed from the cover side,
The substrate is provided with a through hole,
An opening end portion of the through hole on the relay side is opposed to the cover opening portion.   The control unit according to claim 1, wherein a conductive layer is provided on an inner surface of the through hole.

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