JPH0746164A - Magnetic communication equipment - Google Patents

Abstract

PURPOSE:To prevent the Q of a fixed coil arranged closely to a metallic member in magentic communication equipment comprised of a moving coil and the fixed coil. CONSTITUTION:A magnetic plate 5 is arranged on a side opposite to a side where the fixed coil 6 is provided confronting with the moving coil 8 and the two-way communication of information is performed. The magnetic plate 5 is formed in the same size or larger than that of the plane of the fixed coil 6, and the center of it is located on the axis of the fixed coil 6, and it is located between a metallic plate, for example, a shield cabinet plate on the back wall 4 of the fixed coil. The magentic plate 5 is formed in such a way that the magnetic field of the fixed coil 6 is prevented from arriving at the metallic plate on the back wall 4, and eddy current loss generated on the metallic plate can dissipate. In this way, it is possible to keep the sensitivity of information transmission constant and to improve reliability for the equipment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contactless device for transmitting information using a magnetic field, and more particularly to a structure around a fixed coil in a magnetic communication device having a fixed coil and a moving coil.

[0002]

2. Description of the Related Art A non-contact information transmission device in which one of the transmitting and receiving coils is fixed and the other transmitting and receiving coil moves, has been put to practical use in automatic ticket gates of ski lifts and automatic train stop devices.

In an automatic ticket gate of a lift, a ticket inspecting device including a fixed coil is installed at a ticket gate of a landing, a user purchases a card-shaped voucher containing a moving coil, and the user purchases the card-shaped voucher. When you have it and pass the ticket inspection device, the fixed coil is moved by the moving coil passing through the opposite position in the ticket inspection device.
It is configured to instantly transmit bidirectional information such as ticket type, date and time, number of times of use, etc., and the control circuit of the ticket inspection device issues various signals according to ticket information, opens doors, displays alarms, etc. Has been done.

In order to prevent the driver from overlooking the traffic light and putting the train in a dangerous state, the automatic train stopping device gives an alarm on the train at a red light or when the speed limit is exceeded, and when the vehicle is ignored, an emergency brake is applied. It is a facility to call.

FIG. 3 is a principle diagram showing an example of a structure for providing information on the vehicle. The ground element 1 is a resonance circuit installed between rails and has a fixed coil 2. Car child 3
Is an oscillator equipped on the vehicle. By utilizing the fact that the oscillation frequency on the vehicle is drawn into the resonance frequency of the ground element 1 only when the top element 3 passes over the ground element 1 by switching the capacitor of the ground element 1 according to the signal condition. This is a configuration called a point control type that selectively detects the resonance frequency of 1 and gives a trigger to the control device of the automatic train stop device.

[0006]

The fixed coil of such a magnetic communication device transmits and receives information on one side in the axial direction of the fixed coil so as to face the moving coil at regular intervals. When a metal member is present close to the other side of the fixed coil in the axial direction, an eddy current due to the magnetic field of the fixed coil flows into the metal member, and the Q of the fixed coil decreases, so that the sensitivity of the fixed coil as a receiving antenna decreases. To do. As a result, information may not be transmitted correctly.

An object of the present invention is to provide a magnetic communication device in which the metal member existing in the vicinity of the fixed coil and facing each other is prevented from causing a decrease in Q of the fixed coil.

[0008]

In a magnetic communication device according to the present invention, a magnetic plate having an area larger than the main surface of a fixed coil is provided on the opposite side of the fixed coil in the axial direction from the side facing the moving coil. It is characterized in that it is arranged between the fixed coil and the metal member facing the fixed coil so that the center is on the axis of the fixed coil.

That is, according to the present invention, on one side in the axial direction of the fixed coil installed at a predetermined position, the moving coil provided on the moving body faces the fixed coil at a distance from the fixed coil to perform bidirectional transmission of information. In a magnetic communication device, a magnetic plate having a size larger than the main surface of a fixed coil is provided on the opposite side of the fixed coil facing the moving coil, and a metal member facing the fixed coil with the center on the axis of the fixed coil. And a magnetic coil which is arranged between the fixed coil and the metal member so as to interrupt the magnetic coupling between the fixed coil and the metal member.

[0010]

The magnetic plate blocks magnetic coupling between the fixed coil and the metal member existing close to the fixed coil to prevent eddy current from flowing through the metal member due to an AC signal when the moving coil passes through. However, the Q of the fixed coil is prevented from decreasing due to eddy current loss. The magnetic plate also reduces the influence of an external magnetic field on the fixed coil.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment shown in FIG. 1 is a perspective view of the main part of the ticket inspection device at a lift landing. A magnetic plate 5 made of a ferrite plate having soft magnetic characteristics is fixed to the inner surface of a back wall of a metal shield housing (hereinafter referred to as a housing) of a ticket inspection apparatus installed at a landing. The housing has a box shape (the drawing shows a part of the back wall 4 and the side wall) with the front left opening in the drawing. A flat fixed coil 6 is arranged in the housing with its rectangular main surface parallel to the back wall 4 and spaced from the back wall 4. The magnetic plate 5 has its center on the axis of the fixed coil 6, and is fixed to the back wall 4 so as to face the fixed coil 6.

A shallow ticket running path 9 having a U-shaped cross section is provided on the opening side of the housing parallel to the back wall 4 so that the moving coil 8 incorporated in the ticket 7 can face the fixed coil 6. ,
And they are arranged horizontally.

A case where the ground element 1 in FIG. 3 is installed on the iron bridge 10 is shown in FIG. 2 as a second embodiment in which a main part of the ground element 1 is vertically cut.

In the grounding element 1, a magnetic plate 12 made of, for example, a plurality of ferrite tiles is laid in a recess on the inner bottom of a resin closed container 11 having a thick bottom, and the magnetic plate 12 is provided in the center of the magnetic plate 12. Flat coil 2 which is one size smaller than
(Simply shown) is placed lying down.

The magnetic material used for the magnetic plate may be a metal-based material, a metal oxide-based material, an amorphous material, or a powder magnetic material made of metal magnetic fine powder, etc., which is appropriately selected according to the frequency of the signal to be used. To do.

[0016]

EFFECTS OF THE INVENTION A magnetic plate having a size larger than the main surface of the fixed coil is provided between the fixed coil and a metal member close to and opposed to a metal casing or an iron bridge. By arranging so as to shield magnetically, magnetic coupling between the fixed coil and the metal member is cut off, and by disposing a magnetic plate having a size larger than the main surface of the fixed coil between the fixed coil and the metal member, It is possible to prevent the eddy current flowing in the metal member, eliminate the eddy current loss, and prevent the Q of the fixed coil from decreasing.
The normal operation of the device can be maintained and the reliability of the device is improved. The magnetic plate also serves as a protective plate against a disturbing magnetic field from the outside, and is also effective in preventing malfunction of the transmission device.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a ticket inspection apparatus showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of a grounding element of an automatic train stopping device, showing another embodiment of the present invention.

FIG. 3 is a principle diagram showing an example of a configuration of information transmission of an automatic train stop device.

[Explanation of symbols]

 1 Ground Element 2, 6 Fixed Coil 3 Car Upper Element 4 Back Wall 5, 12 Magnetic Plate 7 Ticket 8 Moving Coil 9 Ticket Runway 10 Iron Bridge 11 Resin Sealed Container

Claims (1)

[Claims] 1. A magnetic communication device for performing bidirectional transmission of information on one side in the axial direction of a fixed coil installed at a predetermined position, wherein a moving coil provided in a moving body faces the fixed coil at a distance from the fixed coil and faces the fixed coil. In the above, a magnetic plate having a size larger than the main surface of the fixed coil is provided on the opposite side of the fixed coil facing the moving coil, and between the fixed coil and the metal member facing the fixed coil with the center on the axis of the fixed coil. And a magnetic communication device configured to cut off magnetic coupling between the fixed coil and the metal member.