JP2007184132A - Electromagnetic relay - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic relay capable of maintaining close sealing by preventing cracks of a sealing agent even when a terminal becomes large in size, and with high reliability. <P>SOLUTION: The electromagnetic relay is composed of an electromagnetic relay main body (not illustrated) installed on a base 3, a terminal 2 protruding downward from the bottom face of the base 3, and a cover 1 installed so as to cover the electromagnetic relay main body and the side wall part of the base. A groove part 6 of nearly constant width and constant depth is installed at the bottom face of the base 3, and a sealing agent 5 made of resin for insulating sealing is filled in the groove part 6, in the spacing between the side wall part of the base 3 and the cover 1, and in the spacing between the base 3 and the cover 1 and the terminal 2, and the relay is adhered, fixed, and sealed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electromagnetic relay, and more particularly to a hermetic electromagnetic relay capable of energizing a large current (about 100 A) for in-vehicle use.

  In recent years, with the progress of car electronics / demands for improving fuel efficiency, the movement of replacing power steering from hydraulic pressure to EPS (electric power steering) has become full-scale. Accordingly, as a peripheral technology for realizing this, a performance capable of flowing a large current of 100 A to an electromagnetic relay, which is an electronic component, has begun to be demanded. In order to enable such a large current flow, the terminals of the electromagnetic relay have to have a large cross-sectional area, which inevitably increases in size. At this time, in the sealed electromagnetic relay, the enlarged terminal, the base on which the electromagnetic relay main body is installed, and the cover that covers the main body must be sealed with a sealant.

  As a prior art of a sealed electromagnetic relay having a large terminal, for example, Patent Document 1 is cited. This describes a technique related to the structure of an electromagnetic relay that allows a larger current to flow. However, a technique suitable for sealing the base and cover of an electromagnetic relay having an enlarged terminal is not described. Moreover, patent document 2 is mentioned as a prior art of a sealed electromagnetic relay, for example. Although there is a description regarding prevention of peeling between the cover and the sealant, there is no description of a technique regarding prevention of cracking of the sealant around the terminals.

Japanese Patent Application No. 2004-158951 JP 2004-342398 A

  In general, in order to confirm whether or not the sealed electromagnetic relay is of a quality that sufficiently satisfies the customer's trust, it is assumed that the welding thermal stress or the use environment when joining to the circuit board is assumed, and the -40 of severer conditions A test is performed to check whether the sealing performance is maintained by repeatedly applying a thermal stress of from ℃ to +125 ℃.

  FIG. 2 is a diagram showing a conventional electromagnetic relay disclosed in Patent Document 1. As shown in FIG. 2 (a) and 2 (b) are perspective views as seen from the bottom side before and after application of the sealant, respectively, and FIG. 2 (c) is a bottom view after application of the sealant. .

  In FIG. 2, this electromagnetic relay includes an electromagnetic relay body (not shown) installed on the base 9, a terminal 2 protruding downward (upward in the drawing) from the bottom surface of the base 9, an electromagnetic relay body and a side wall portion of the base The cover 1 is disposed so as to cover the gap, and the gap between the side wall portion of the base 9 and the cover 1 and the gap between the base 9 and the cover 1 and the terminal 2 is a sealing agent 11 which is a resin for insulating sealing. Has been injected.

  Usually, the component of the terminal 2 is substantially copper, and the base 9 and the cover 1 are plastic resin. Therefore, the terminal 2 is easier to warm and cool than the base 9 and the cover 1. Therefore, when a thermal stress is applied, the portion around the terminal of the sealing agent 11 is heated and cooled earlier than the portion around the cover 1 and the base 9, and a temperature difference is generated in the sealing agent 11. Become. That is, while the sealing agent around the terminal 2 tends to expand or contract, the sealing agent around the cover 1 and the base 9 away from the terminal tends to suppress it. For this reason, a stress is generated there and a crack is generated when it exceeds the endurance range of the sealant, and further, the crack progresses due to the repeated action of the thermal stress, which eventually leads to airtight deterioration. When such severe cooling / heating stress is repeatedly applied, there is a problem that the larger the terminal becomes, the faster the crack starts to be generated, so that the prescribed number of repetitions cannot be satisfied.

  Accordingly, an object of the present invention is to provide a highly reliable electromagnetic relay that can prevent the sealing agent from cracking and maintain hermeticity even when the terminal is enlarged.

  In order to solve the above problems, an electromagnetic relay of the present invention covers an electromagnetic relay main body installed on a base, a terminal projecting downward from a bottom surface of the base, and the electromagnetic relay main body and a side wall portion of the base. An electromagnetic relay comprising: a cover installed on the base; a gap between the side wall of the base and the cover; and a resin for insulation sealing injected into the gap between the base and the cover and the terminal. A groove portion having a substantially uniform width and a substantially uniform depth is provided around the terminal on the bottom surface where the terminal protrudes, and the insulating sealing resin is injected into the groove portion. The thickness of the terminal may be 0.8 mm or more, or the width of the terminal may be 4 mm or more. Further, it is desirable that the width of the groove around the terminal is 1.5 mm or less, and the ratio Wa / Wb between the maximum width Wa and the minimum width Wb of the groove is 2 or less. Further, it is desirable that the depth of the groove around the terminal is 1.0 mm or less, and the ratio Da / Db between the maximum depth Da and the minimum depth Db of the groove is 2 or less.

  The electromagnetic relay of the present invention is provided with a groove having a substantially uniform width and uniform depth on the bottom surface of the base around the terminal, and when a thermal stress is repeatedly applied to the electromagnetic relay by injecting a sealing agent and fixing it. In addition, cracks are hardly generated in the sealant, and the long-term sealing property is improved, and high reliability is obtained.

  Next, embodiments of the present invention will be described based on examples with reference to the drawings. However, the present invention is not limited to this embodiment.

  FIG. 1 is a diagram showing an embodiment of an electromagnetic relay according to the present invention. FIGS. 1A and 1B are perspective views as seen from the bottom side before and after application of the sealant, respectively, and FIG. 1C is a bottom view after application of the sealant.

  In FIG. 1, this electromagnetic relay includes an electromagnetic relay main body (not shown) installed on a base 3, a terminal 2 protruding downward (upward in the drawing) from the bottom of the base 3, and an electromagnetic relay as in the conventional electromagnetic relay. It comprises a relay body and a cover 1 installed so as to cover the side wall portion of the base. The gap between the side wall portion of the base 3 and the cover 1 and the gap between the base 3 and the cover 1 and the terminal 2 are for insulation sealing. A sealing agent 5 which is a resin is injected, fixed and sealed.

  However, in the electromagnetic relay according to the present embodiment, a groove portion 6 having a substantially uniform width and a uniform depth is provided on the bottom surface of the base 3 around the terminal 2, and the sealant 5 is injected into the groove portion 6 so that the terminal 2 and the base 3 and The cover 1 is bonded and fixed. The width of the groove 6 can be set to a substantially constant value in the range of about 0.5 to 1.5 mm around the terminal 2, and the depth is also almost in the range of about 0.5 to 1.0 mm. It can be a constant value.

  The conventional electromagnetic relay shown in FIG. 2 also has a groove 12 around the terminal 2, but its width varies between about 1.0 to 5.5 mm depending on the location, and the depth of the groove is 0.3. There is a change of about 1.0 mm.

  In addition, the crack prevention effect of the sealing agent 5 increases by making the width | variety and depth of the groove part 6 small to the limit which the nozzle at the time of inject | pouring the adhesive strength and the sealing agent 5 can enter.

  50 electromagnetic relays according to the examples of the present invention and 50 conventional sealed electromagnetic relays shown in FIG. 2 as comparative examples were produced, and the appearance inspection was performed after applying a cooling cycle. The conventional hermetic electromagnetic relay has the groove 12 in the base 9 around the large terminal 2, but the width and depth are not uniform and large as described above. On the other hand, in the embodiment of the present invention, the width and depth of the groove 6 are substantially uniform around the terminal, and the width is narrower than before. Also, the depth is smaller than that of the prior art and is almost uniform. The present example and the conventional comparative example were manufactured in the same shape except for the difference in the shape of the groove portion of the base around the terminal, and the sealing agent was injected under the same conditions.

  The cooling / heating cycle was performed for 25 cycles in a pattern in which the test product was put in an environmental test tank and the temperature setting of −40 ° C. and + 125 ° C. was alternately switched every 30 minutes. As a result of visual inspection, cracks of the sealing agent were observed in 22/50 electromagnetic relays of the conventional comparative example, but no cracks were observed in the electromagnetic relays of the examples of the present invention. (0/50).

  The thermal conductivity of the terminal is about 2000 times larger than that of the base resin. Therefore, the sealant near the terminal is easier to warm and cool than the sealant near the base resin. The difference in thermal temperature creates a local expansion / contraction difference, causing distortion and cracking. When the terminal is enlarged, for example, in the case of a large terminal having a terminal thickness of about 0.8 mm or more, or a width of about 4 mm or more, the amount of the sealing agent present around the terminal is increased, and the appropriate width and thickness are increased. If the width (thickness) is not uniform and the width and thickness are not uniform, the temperature difference in the sealant becomes larger and a large strain is generated. Cracks occur. From the above test results, it was proved that the solution can be obtained by the present invention.

  As described above, the electromagnetic relay in which the sealing agent of the present invention is injected and bonded and fixed is provided with a groove having a substantially uniform width and a uniform depth in the base around the terminal, and further, the width and the depth as much as possible. By reducing the size, the temperature difference inside the sealant when a thermal stress is applied is suppressed, so it is estimated that cracking of the sealant can be prevented, and even when the terminal is larger than the conventional electromagnetic relay However, the sealing performance is improved in the long term, and high reliability is obtained.

  It is desirable that the width and depth of the base groove around the terminal be uniform, but the width of the groove is 1.5 mm or less and the maximum width Wa of the groove compared to a conventional electromagnetic relay. The ratio Wa / Wb of the minimum width Wb is 2 or less, or the depth of the groove is 1.0 mm or less, and the ratio Da / Db of the maximum depth Da to the minimum depth Db is 2 or less. If it exists, sufficient effect of the above-mentioned this invention is acquired.

The figure which shows the Example of the electromagnetic relay by this invention. FIG. 1A is a perspective view seen from the bottom side showing a state before injecting the sealant, and FIG. 1B is a perspective view seen from the bottom side showing a state after injecting the sealant. FIG.1 (c) is a bottom view which shows the state after inject | pouring sealing agent. The figure which shows an example of the conventional sealed electromagnetic relay. FIG. 2A is a perspective view seen from the bottom side showing the state before injecting the sealing agent, FIG. 2B is a perspective view seen from the bottom side showing the state after injecting the sealing agent, FIG.2 (c) is a bottom view which shows the state after inject | pouring sealing agent.

Explanation of symbols

2 Terminals 3, 9 Base 1 Cover 5, 11 Sealant 6, 12 Groove

Claims (4)

  An electromagnetic relay main body installed on the base; a terminal projecting downward from the bottom surface of the base; a cover installed to cover the electromagnetic relay main body and the side wall of the base; the side wall of the base; In an electromagnetic relay composed of a gap between the cover and the base and an insulating sealing resin injected into the gap between the cover and the terminal, the base has a substantially uniform width around the protrusion of the terminal on the bottom surface of the base. An electromagnetic relay comprising a groove portion having a substantially uniform depth, and the insulating sealing resin is injected into the groove portion.   The electromagnetic relay according to claim 1, wherein the thickness of the terminal is 0.8 mm or more, or the width of the terminal is 4 mm or more.   3. The electromagnetic relay according to claim 1, wherein a width of the groove around the terminal is 1.5 mm or less, and a ratio Wa / Wb between the maximum width Wa and the minimum width Wb of the groove is 2 or less. .   The depth of the groove around the terminal is 1.0 mm or less, and the ratio Da / Db between the maximum depth Da and the minimum depth Db of the groove is 2 or less. The electromagnetic relay of any one of Claims.

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