JP2005032672A - Electromagnetic relay - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic relay which provides an electrostatic shield and reduces a electromagnetic induction noise. <P>SOLUTION: The electromagnetic relay which is an improved one that switches on/off contacts of relay leads with an exciting coil, is characterised by being provided with a seat plate and a shield case to cover the seat plate. The seat plate has a plurality of holes, and on the upper or lower side of the seat plate, a nonconductive electric-wave-absorbing part is formed around the holes through which exciting coil leads and the relay leads are inserted, and a conductive electric-wave-absorbing part is formed in the area where a nonconductive electric-wave-absorbing part is not formed. The conductive electric-wave-absorbing part is electrically connected to a grounding lead for grounding, the grounding lead being inserted through the hole of the seat. On the end part of the inner surface of the shield case, a nonconductive electric-wave-absorbing part is formed. On the other area of the inner surface thereof, a conductive electric-wave-absorbing part is formed, which is electrically connected to the conductive electric-wave-absorbing part of the seat. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electromagnetic relay capable of reducing electromagnetic induction noise together with an electrostatic shield.

  In the electromagnetic relay, a relay element is sealed in a glass tube, and a contact of the relay element is turned on and off by an electromagnetic coil. For example, it is described in Patent Document 1. Such an electromagnetic relay will be described with reference to FIG.

  In FIG. 4, the printed circuit board 1 is provided with a plurality of holes 11. The relay socket 2 is provided with a plurality of terminals 21 to be inserted and fixed in the holes 11 of the printed circuit board 1. The pedestal 3 is provided with a relay lead 31, a glass tube 32, an exciting coil 33, and a lead 34, and is attached to the relay socket 2. The relay lead 31 is covered with the outer periphery of a glass tube 32, and an excitation coil 33 is wound around the glass tube 32. The relay lead 31 and the excitation coil 33 are electrically connected to the terminal 21 of the relay socket 2. The shield case 4 is made of aluminum or the like, and is attached to the pedestal 3. The shield case 4 is electrically connected to the terminal 21 of the relay socket 2 via the lead 34 of the pedestal 3 and grounded, and is electrically connected to the ground of the printed circuit board 1. Connect and provide electrostatic shielding.

  In such a device, the shield case 4 reduces noise that interferes with other electromagnetic relays, the pattern of the printed circuit board 1 and the electronic circuit from signals transmitted through the electromagnetic relay. Shielding is done.

JP-A-55-166827

  When the electromagnetic relay handles high-speed signals, the relay lead 31 and the body shape are devised for signal transmission, and the characteristic impedance of the signal transmission path, that is, the relay path, is matched with the line impedance of the pattern of the printed circuit board 1. Therefore, it is designed so that unnecessary radiation is not generated by suppressing the influence of signal reflection.

  However, in recent years, the rise and fall times of the signal propagating through the electromagnetic relay have become faster, leading to an increase in the signal frequency band, and there has been a situation where impedance matching in the high frequency region cannot always be achieved. When such mismatching occurs, not only noise due to electrostatic coupling but also noise due to an induced magnetic field mainly due to the inductance component of the line is generated, and this influences interference from other electromagnetic devices and patterns from the electromagnetic relay. Effect.

  On the other hand, when iron is used for the shield case 4, heat loss due to eddy currents is generated in the radiated magnetic field, and electromagnetic induction noise can be reduced.

  However, the lower surface on which the electromagnetic relay is mounted may contact the chassis directly with the relay lead or printed circuit board pattern, so that the case is opened and the radiated magnetic field wraps around from the lower surface of the electromagnetic relay.

  On the other hand, although Cited Document 1 shows a configuration in which a case is covered with a magnetic tape, electrostatic shielding cannot be performed.

  Accordingly, an object of the present invention is to realize an electromagnetic relay capable of reducing electromagnetic induction noise together with an electrostatic shield.

In order to achieve such a problem, the invention according to claim 1 of the present invention is:
In an electromagnetic relay that turns the relay lead contact on and off with an exciting coil,
A plurality of holes are provided, and a non-conductive radio wave absorber is formed around the hole into which the exciting coil and the relay lead are inserted on the upper surface or the lower surface, and the non-conductive radio wave absorber is not formed. A pedestal in which a conductive radio wave absorber is formed, the conductive radio wave absorber is electrically connected, and a ground lead for grounding is inserted into the hole;
A non-conductive radio wave absorber is formed on the end on the inner wall surface, and a conductive radio wave absorber is formed on the other inner wall surface, electrically connected to the conductive radio wave absorber of the pedestal, A shield case covering the pedestal is provided.

The invention according to claim 2
In an electromagnetic relay that turns the relay lead contact on and off using an excitation coil,
A pedestal provided with a hole into which the exciting coil and the relay lead are inserted and a hole into which a ground lead to be grounded is inserted;
A shield case in which a non-conductive wave absorber is formed on the end on the inner wall surface, and a conductive wave absorber is formed on the other inner wall surface;
The pedestal is attached, and a non-conductive radio wave absorber is formed on the upper surface or the lower surface of the signal pin around which the exciting coil and the relay lead are inserted into the hole, and the non-conductive radio wave absorber is not formed. A conductive radio wave absorber is formed in the part, and is electrically connected to the conductive radio wave absorber of the shield case via the conductive radio wave absorber, and the ground lead is grounded through the hole. And a socket.

The present invention has the following effects.
According to the first and second aspects, since the inner wall of the relay case is covered with the radio wave absorber, noise caused by electromagnetic induction generated from the other relay is reduced by heat conversion. Further, inductive unnecessary radiation noise generated from itself is similarly reduced by heat conversion. Then, the non-conductive electromagnetic wave absorbing portion can conduct electricity in the conductive electromagnetic wave absorbing portion while maintaining insulation, and can be grounded via the ground lead, thereby realizing an electrostatic shield.

  According to the second aspect, since the socket is provided with the non-conductive radio wave absorber and the conductive radio wave absorber, the shield member does not need to be replaced even when the electromagnetic relay, which has a limited life, is replaced. Thereby, it can be made cheap.

  Hereinafter, the present invention will be described in detail with reference to the drawings. 1A and 1B are configuration diagrams showing an embodiment of the present invention, in which FIG. 1A is a side sectional view and FIG. 1B is a top view of a pedestal 5. Here, the printed circuit board 1 and the relay socket 2 shown in FIG. 4 are omitted.

  In FIG. 1, a pedestal (base material) 5 is formed in a plate shape, provided with holes 51 and 52, and a non-conductive radio wave absorber 53 is formed around the hole 51 on the upper surface portion, thereby being non-conductive. The conductive radio wave absorber 54 is formed in a portion where the conductive radio wave absorber 53 is not formed. The non-conductive radio wave absorber 53 is formed by spraying an oxide-based ferromagnetic powder having radio wave absorptivity and having no electrical conductivity after applying an adhesive. The conductive radio wave absorber 54 is formed by spraying conductive silicon carbide or non-magnetic metal powder after applying an adhesive, having electromagnetic absorption. The pedestal 5 is provided with a relay lead 55, a glass tube 56, an exciting coil 57, and a ground lead 58, and is attached to the relay socket. The relay lead 55 is covered with a glass tube 56, and an exciting coil 57 is wound around the outer periphery of the glass tube 56. The signal lead 551 of the relay lead 55 and the signal lead 571 of the exciting coil 57 are inserted into the hole 51 and electrically connected to the relay socket. Then, the relay lead 55 turns on and off the contact by the exciting coil 57. The ground lead 58 is inserted into the hole 52 and electrically connected to the relay socket. The relay lead 55, the glass tube 56, the exciting coil 57, and the ground lead 58 are fixed with a coating material 59.

  The relay case 6 is made of metal or non-metal, and is attached to the pedestal 5. A non-conductive radio wave absorber 61 is formed on the end on the inner wall surface by the thickness of the pedestal 5. Conductive radio wave absorber 62 is formed. The conductive radio wave absorber 62 is electrically connected to the conductive radio wave absorber 54. The non-conductive radio wave absorber 61 and the conductive radio wave absorber 62 are made of the same material as the non-conductive radio wave absorber 53 and the conductive radio wave absorber 54, respectively, and are formed by spraying after applying an adhesive.

  The assembling operation of such an apparatus will be described with reference to FIG. The relay case 6 is fitted to the base 5. As a result, the conductive radio wave absorber 62 of the relay case 6 and the conductive radio wave absorber 54 of the base 5 are electrically connected, and the conductive radio wave absorber 62 connects the conductive radio wave absorber 54 and the ground lead 58 to each other. Is grounded.

  As a result, since the inner wall of the relay case 6 is covered with the radio wave absorber, noise caused by electromagnetic induction generated from the other relay is reduced by heat conversion. Further, inductive unnecessary radiation noise generated from itself is similarly reduced by heat conversion. Then, while maintaining insulation by the non-conductive radio wave absorbers 53 and 61, the conductive radio wave absorbers 54 and 62 conduct electricity and ground through the ground lead 58, thereby realizing an electrostatic shield.

  Next, a second embodiment will be described with reference to FIG. 3A is a side sectional view, FIG. 3B is a side sectional view of the socket 7, and FIG. 3C is a top view of the socket 7. Here, the same components as those shown in FIG.

  In FIG. 3, a pedestal 50 is provided instead of the pedestal 5, and the difference from the pedestal 5 is that the conductive radio wave absorber 53 and the nonconductive radio wave absorber 54 are not formed.

  The socket 7 is formed in a plate shape and is provided with a signal pin (terminal) 71 and a ground pin (terminal) 72. A non-conductive radio wave absorber 73 is formed around the signal pin 71 on the upper surface portion, so that it is non-conductive. A conductive radio wave absorber 74 is formed in a portion where the conductive radio wave absorber 73 is not formed. The signal pin 71 has a hole, and the signal lead 551 of the relay lead 55 and the signal lead 571 of the exciting coil 57 are inserted into the hole. The ground pin 72 has a hole, and the ground lead 58 is inserted therein. The non-conductive radio wave absorber 73 and the conductive radio wave absorber 74 are made of the same material as the non-conductive radio wave absorber 53 and the conductive radio wave absorber 54, respectively, and are formed by spraying after applying an adhesive.

  In the assembling operation of such a device, the relay case 6 is fitted to the base 50. Then, the base 50 and the relay case 6 are fitted into the socket 7. Thereby, the conductive radio wave absorber 62 of the relay case 6 and the conductive radio wave absorber 74 of the socket 7 are electrically connected, and the conductive radio wave absorber 62 is connected to the conductive radio wave absorber 74, the ground lead 58, It is grounded via the ground pin 72.

  As described above, since the non-conductive radio wave absorber 73 and the conductive radio wave absorber 74 are provided in the socket 7, even when the electromagnetic relay, which has a limited life, is replaced, it is not necessary to replace the shield member. Thereby, it can be made cheap.

  The present invention is not limited to this, and the non-conductive radio wave absorbers 53, 61, 73 and the conductive radio wave absorbers 54, 62, 74 are configured by spraying powder after application after bonding. However, the structure which adhere | attaches after adhering powder to a nonwoven fabric may be sufficient. Moreover, the structure which adhere | attaches after adhering powder to a film etc. may be sufficient.

  Moreover, although the structure which provided the nonelectroconductive wave absorption parts 53 and 73 and the electroconductive wave absorption parts 54 and 74 in the upper surface part of the base 5 and the socket 7 was shown, the structure provided in a lower surface part may be sufficient, respectively.

It is the block diagram which showed the 1st Example of this invention. It is the figure which showed the assembly block diagram of the apparatus shown in FIG. It is the block diagram which showed the 2nd Example of this invention. It is the figure which showed the structure of the conventional electromagnetic relay.

Explanation of symbols

5, 50 Base 51, 52 Hole 53, 61, 73 Non-conductive radio wave absorber 54, 62, 74 Conductive radio wave absorber 58 Ground lead 6 Shield case 7 Socket 71 Signal pin 72 Ground pin

Claims (2)

In an electromagnetic relay that turns the relay lead contact on and off with an exciting coil,
A plurality of holes are provided, and a non-conductive radio wave absorber is formed around the hole into which the exciting coil and the relay lead are inserted on the upper surface or the lower surface, and the non-conductive radio wave absorber is not formed. A pedestal in which a conductive radio wave absorber is formed, the conductive radio wave absorber is electrically connected, and a ground lead for grounding is inserted into the hole;
A non-conductive radio wave absorber is formed on the end on the inner wall surface, and a conductive radio wave absorber is formed on the other inner wall surface, electrically connected to the conductive radio wave absorber of the pedestal, An electromagnetic relay comprising a shield case that covers a pedestal. In an electromagnetic relay that turns the relay lead contact on and off with an exciting coil,
A pedestal provided with a hole into which the exciting coil and the relay lead are inserted and a hole into which a ground lead to be grounded is inserted;
A shield case in which a non-conductive radio wave absorber is formed on the end on the inner wall surface, and a conductive radio wave absorber is formed on the other inner wall surface;
The pedestal is attached, and a non-conductive radio wave absorber is formed on the upper surface or the lower surface of the signal pin around which the exciting coil and the relay lead are inserted into the hole, and the non-conductive radio wave absorber is not formed. A conductive radio wave absorber is formed in the part, and is electrically connected to the conductive radio wave absorber of the shield case via the conductive radio wave absorber, and the ground lead is grounded through the hole. An electromagnetic relay comprising a socket.

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