JPH0439767B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a substantially ring-shaped feedthrough capacitor used to prevent malfunctions caused by external nozzles of an electronic control device.

[Background of the invention]

In order to prevent malfunctions caused by external nozzles, electronic control devices generally use feedthrough capacitors between the control device and lead wires that connect external circuits. The conventional mounting structure of this feedthrough capacitor is generally as shown in Fig.
128824).

In FIG. 1, a feedthrough capacitor 10 is inserted into a hole provided in a relatively thick metallic shield plate 12, and its outer electrode is joined to the shield plate 12. The inner peripheral surface forming the inner electrode of the feedthrough capacitor 10 is coupled to a terminal 16 passing through the center hole 14. This terminal 16 is embedded in synthetic resin by molding and fixed.

This type of conventional feedthrough capacitor mounting structure has problems with the reliability of the joints, and especially when used in electronic control devices for automobiles, the usage environment is harsh and conduction failures occur at the joints. There was this inconvenience. That is, since the operating temperature of electronic control devices for automobiles reaches as high as -40 to 130 degrees Celsius, stress caused by differences in the coefficient of thermal expansion of each structural component cannot be ignored. For example, in the mounting structure of feedthrough capacitor 10 shown in FIG. 1, terminal 16 and terminal 1
Thermal expansion or contraction occurs in the synthetic resin in which 6 is embedded. In this case, the thermal expansion coefficient of synthetic resin is generally large, and the terminal 16 is made of metal.
It is very difficult to set the same thermal expansion coefficients for the synthetic resin and the synthetic resin. For this reason, for example, when the temperature around the feedthrough capacitor 10 becomes high, the coefficient of thermal expansion of the synthetic resin decreases at the terminal 16.
Terminal 16 is larger than the thermal expansion coefficient of
is pulled in the direction of arrow P with respect to the shield plate 12. The force received by the terminal 16 acts on the soldered portion between the feedthrough capacitor 10 and the terminal 16, and shear stress is generated in the soldered portion due to the high rigidity of the shield plate 12, causing peeling at the soldered portion. , a conduction failure occurs.

[Purpose of occurrence]

SUMMARY OF THE INVENTION An object of the present invention is to provide a feedthrough capacitor mounting structure that can prevent conduction failure at a joint due to thermal strain caused by differences in thermal expansion coefficients of constituent members.

[Summary of the invention]

In the present invention, the metal plate into which the feedthrough capacitor is inserted and connected to the outer electrode of the feedthrough capacitor is made of a flexible thin plate, so that when stress due to thermal strain is applied to the feedthrough capacitor, the metal plate The plate is bent to prevent large shear stress from occurring at the joint of the feedthrough capacitor, thereby preventing the joint from peeling off and causing poor conduction.

[Embodiments of the invention]

A preferred embodiment of the mounting structure for a feedthrough capacitor according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 shows an example in which the feedthrough capacitor mounting structure according to the embodiment is applied to an electronic control device. In FIG. 2, a metallic housing 2
0 is formed into a substantially box shape, and this housing 2
A printed board 22 constituting a control circuit is fixed inside the housing with screws 24. Various electronic components 26 and 28 are fixed to the printed board 22 by soldering, and a flexible circuit-side terminal 30 made of a thin metal plate is provided. A connector 32 is fixed to one side of the housing 20 with a screw 34.

The connector 32 is integrated with the synthetic resin 36 of the terminal 16 by molding. The terminal 16 consists of a plate-shaped insertion part 38 and a rod-shaped connection part 40. In the connecting portion 40, a ferrite bead 42, which is an inductance element, is fitted onto the side of the insertion portion 38, and a feedthrough capacitor 10 is soldered to the intermediate portion. This feedthrough capacitor 10 is supported by a ground plate 44 sandwiched between the housing 20 and the connector 32.

A metal bushing 48 is attached to the flange portion 46 of the connector 32, and the screw 34 is inserted through the metal bushing 48 so that creep does not occur when the screw 34 is tightened. Further, a convex portion 50 is formed on the connector 32 , and this convex portion 50 is fitted into a bottomed hole formed in the housing 20 .
Positioning relative to 0 is possible. Further, a ring groove is formed in the housing 20, and an O-ring 52 is fitted into the ring groove, thereby ensuring sealing performance at the joint surface between the housing 20 and the connector 32.

Note that the ground plate 44 held between the housing 20 and the connector 32 is electrically connected to the housing 20, as shown in FIGS. 2 and 3.
It is inserted into a hole 54 formed in the housing 20.

The control circuit formed on the surface of the printed board 22 in the housing 20 is shielded around the entire circumference by the housing 20 and a metal shield plate 56 attached to the open upper surface of the housing 20 by means such as caulking. has been done. A synthetic resin cover 58 is fitted into the upper part of the shield plate 56 so as to be in contact with the inner wall of the housing 20, and the peripheral edge is fixed to the housing 20 with an adhesive 60 to seal the inside of the housing 20 from water etc. .

The ground plate 44 is made of a flexible thin metal plate of about 0.1 to 0.2 mm, and as shown in FIG. It is becoming. And ground plate 4
4, a mounting hole 64 for inserting the feedthrough capacitor 10 is formed in the bottom surface of the box-shaped portion 62, a plurality of notch holes 66 are provided in the side surface of the box-shaped portion 62, and a connector is provided in the flange portion 68. A hole 70 into which the 32 convex portions 50 fit is formed. The feedthrough capacitor 10 has a through hole 14,
It consists of a large diameter part 72 and a small diameter part 74.

The feedthrough capacitor 10, connector 32, and ground plate 44 described above are assembled as follows.

First, the connector 32 is placed in a predetermined jig so that the connection part 40 of the terminal 16 is facing upward.
Next, insert the terminal 16 into the mounting hole 64 of the grounding plate 44 so that the box-shaped part of the grounding plate 44 is at the top.
through the hole 70 of the grounding plate 44 and the convex part 50 of the connector 32, and then attaching the grounding plate 44 to the connector 3.
Place it on 2. After that, as shown in Figure 5,
The feedthrough capacitor 10 is installed in the mounting hole 64 of the ground plate 44.
Insert the small diameter portion 74 of the At this time, the earth plate 44
Solder pastes 76 and 78 are applied between the feedthrough capacitor 10 and the feedthrough capacitor 10, and between the feedthrough capacitor 10 and the terminal 16, respectively. after that,
In this state, the connector 32 is passed through a solder reflow oven, the outer periphery of the feedthrough capacitor 10 and the ground plate 44 and the inner periphery of the feedthrough capacitor 10 and the terminal 16 are soldered, and the outer electrode of the feedthrough capacitor 10 is connected to the ground plate 44. 44, connect the inner electrode of the feedthrough capacitor 10 to the terminal 16,
As shown in FIG. 6, the feedthrough capacitor 10, the ground plate 44, and the connector 32 are integrated. Thereafter, the tip of the terminal 16 is bent into an L shape in order to connect it to the circuit side terminal 30. Note that the synthetic resin 36 constituting the connector 32 needs to be made of a resin that can withstand a solder reflow furnace, and it is desirable to use a heat-resistant resin such as glass fiber reinforced polyphenyline oxide resin.

In this way, the connector 32 with the ground plate 44 and the feedthrough capacitor 10 attached thereto is attached to the housing 20 with the screws 34, as shown in FIGS. 1 and 2.

In the embodiment configured as described above, the ground plate 44 to which the feedthrough capacitor 10 is fixed is
Since it is made of a flexible thin plate and has a plurality of notches 66 formed in the side surface of the box-shaped portion 62, even when a slight load is applied in the axial direction of the feedthrough capacitor 10, the ground plate 44 is deformed. Therefore, the connector 32 is exposed to high temperatures, and due to the difference in coefficient of thermal expansion between the synthetic resin 36 and the terminal 16, the synthetic resin 36 is exposed to the terminal 16.
Even if a pulling force is obtained in the direction of the arrow P shown in FIG. Deflect. Moreover, since the circuit side terminal 30 connected to the terminal 16 is made of a thin plate and is bent, it is easily deformed by a small load.
It bends according to the displacement of the terminal 16. As a result, almost no stress is generated in the soldered portions of the feedthrough capacitor 10 and the circuit-side terminal 30, and peeling of the solder, which conventionally occurs, can be eliminated, and good conductivity can always be obtained.

FIG. 7 shows another embodiment of the ground plate. In FIG. 7, the ground plate 44 has a flange portion 68 formed with slightly uneven portions, and has a wavy shape. By making the flange portion 68 wave-like in this manner, it is possible to make good contact with the housing 20 and ensure electrical continuity.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to eliminate the stress at the joint portion of the feedthrough capacitor due to thermal strain, and it is possible to eliminate conduction defects due to peeling.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a conventional feedthrough capacitor mounting structure, FIG. 2 is a sectional view of a control device to which the feedthrough capacitor mounting structure of the embodiment of the present invention is applied, and FIG. A sectional view taken along the line, Figure 4 is an explanatory diagram of the assembly of the feedthrough capacitor, earth plate, and connector, Figure 5 is an explanatory diagram of how to connect the feedthrough capacitor, and Figure 6 is an illustration of the attachment of the earth plate and feedthrough capacitor to the connector. 7th front view
The figure is a side view of another embodiment of the ground plate. 10... Feedthrough capacitor, 12... Shield plate, 1
6...Terminal, 20...Housing, 22...Printed board, 30...Circuit side terminal, 32...Connector, 36...Synthetic resin, 44...Earth plate, 66...Notch hole.

Claims (1)

[Claims] 1. A terminal fixed to a resin, a feedthrough capacitor in which an inner electrode is connected to the terminal passing through a center hole, and this feedthrough capacitor is inserted and connected to an outer electrode of the feedthrough capacitor. What is claimed is: 1. A structure for mounting a feedthrough capacitor comprising a metal plate, the metal plate being a flexible thin plate. 2. Claims characterized in that the flexible thin plate is formed in the shape of a box with a center part bulging to one side and a flange, and a plurality of holes are provided on the side surface of this box-shaped part. Mounting structure of the feedthrough capacitor described in item 1.