JPH09175331A - Immobilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an immobilizer in which keys of different types equipped internally with transponder are bundled by a key ring and which can make engine start smoothly even when the engine starting operation is made with that of keys in bundle which is correct. SOLUTION: This immobilizer is structured so that an antenna 10 is installed only in the upper half circumferential surface of a key cylinder 7, and even in case key 1' of other cars are bundled by a key ring 8, etc., together with a correct key 1, the 1' are hung down when the correct key 1 is inserted into the key cylinder 7 for starting the engine, which should prolong the distance between the transponder(s) 2' installed in such key(s) 1' and the antenna so that its electric field is prevented from acting on the transponder(s) of other key(s). Thus the engine starting operation by the correct key 1 can be responded certainly.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an immobilizer.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
As shown in, the transponder 2 is built in the key 1, and the key ID code signal radio wave 3 transmitted by the transponder 2 when the key 1 is inserted into the key cylinder is received by the antenna coil 5 of the immobilizer 4 incorporated in the key cylinder. Demodulates and decodes it, compares it with the key ID code registered in the immobilizer 4, gives an engine operation permission command to the engine control unit 6 when they match, and gives a fuel injection stop command to the engine control unit 6 when they do not match. Some vehicles incorporate an immobilizer system that stops the engine and prohibits unauthorized movement of the vehicle.

In such a vehicle, conventionally, as shown in FIG. 5, the antenna coil 5 of the immobilizer 4 is formed into a ring shape, and the key 1 is inserted into the key cylinder 7 so that a weak key ID code from the transponder 2 can be obtained. Signal wave 3
Is mounted on the entire circumference of the end portion of the key cylinder 7 on the side of the key insertion opening so that the key can be received.

[0004]

However, such a conventional immobilizer has the following problems. As shown in FIG. 5, in the case of a driver using a plurality of automobiles, a plurality of keys 1, 1 ′ are bundled by one key ring 8 or the like, and the key 1 suitable for the automobile to be driven is keyed. The normal form is to insert into the cylinder 7 for use. At this time, the other key 1'bundled together is in the form of being hung by the key ring 8, but when the transponder 2'is also incorporated in the other key 1 ', the transponder of the other key 1'is The distance between 2'and the lower half of the antenna coil 5 becomes short.

At this time, if the antenna coil 5 has a ring shape, the electric field generated by the antenna coil 5 also has a cylindrical shape. Therefore, when the transponder 2'of the other key 1'approaches this electric field, it reacts to the electric field. , The transponder 2'transmits the key ID code signal radio wave 3 ', and mutual interference occurs with the key ID code signal radio wave 3 from the transponder 2 of the regular key 1, resulting in the engine starting failure. was there.

The present invention has been made in view of the above conventional problems, and a signal wave from a transponder built in a key of another automobile in which the shape of the antenna of the transponder is bundled together by a key ring or the like. It is an object of the present invention to provide an immobilizer that prevents occurrence of mutual interference with a key and can reliably respond to an engine start operation by a regular key even when a plurality of keys are bundled together.

[0007]

According to the present invention, a key ID code signal radio wave transmitted from a transponder built in a key is received by an antenna and collated, and when they do not match, an engine stop command is sent to an engine control unit. In the transmitting immobilizer, the key ID from the transponder
An antenna for receiving a code signal radio wave is attached to the upper half peripheral surface of the end portion of the key cylinder on the key insertion opening side.

In the immobilizer of the present invention, by mounting the antenna only on the upper half peripheral surface of the key cylinder,
Even if the keys of other cars are bundled together with the regular key with a key ring, etc., if you insert the regular key into the key cylinder to start the engine, the other key becomes dangling and the other key The distance between the transponder built in the vehicle and the antenna becomes long, the electric field of the antenna can be prevented from acting on the transponder of another key, and the engine start operation by the regular key can be reliably responded.

[0009]

As described above, according to the present invention, since the antenna is attached only to the upper half peripheral surface of the key cylinder, when the keys of other automobiles are bundled with the key ring together with the regular key. However, if you insert a legitimate key into the key cylinder to start the engine, the other key will hang and the distance between the transponder built into the other key and the antenna will be longer, and the electric field of the antenna will be different. The key can be prevented from acting on the transponder, and the engine can be smoothly started by the regular key.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows the structure of a key cylinder 7 incorporating an immobilizer, keys 1, 1 ', and an antenna 10. As shown in FIG. 2, the antenna 10 has a structure in which the coil 12 is formed up to the upper half of the bobbin 11 made of a non-magnetic material, that is, a position of about 180 ° which makes about half a turn around the start position of the key 1 at 0 °. The antenna 10 is attached to the end of the key cylinder 7 on the key insertion opening side.

The winding form of the coil 12 is not particularly limited, but as an example, as shown in FIG. 3, a semi-cylindrical core 13 made of a ferromagnetic material such as amorphous or ferrite is prepared, and the coil is wound on the core 13. Can be wound, or folded back in a semicircle, and attached to the upper half of the bobbin 11.

Next, the operation of the immobilizer having the above configuration will be described. The circuit configuration of the transponder 2, the immobilizer 4, and the engine control unit 6 built in the key 1 is as shown in FIG.

As shown in FIG. 1, keys 1 and 1'of a plurality of automobiles are bundled together by a key ring 8, and one of the regular keys 1 is a key cylinder 7 When the engine starting operation is started by inserting the key 1'in another vehicle, the key 1'of the other vehicle is hung by the key ring 8.

Then, when the regular key 1 is turned, the antenna coil 12 generates an electric field, and the transponder 2 senses the electric field and transmits the key ID code signal radio wave 3. When the antenna coil 12 receives this, the immobilizer 4 shown in FIG. 4 demodulates and decodes the key ID code signal, collates with the key ID code registered in advance, and when they match, the engine control unit 6 is notified. The engine start permission command is output and the engine operates.

By the way, since the antenna coil 12 is formed only in the upper half of the key cylinder 7, the electric field generated by the antenna coil 12 when the key 1 is turned is hung from the regular key 1 by the key ring 8. It does not reach the transponder 2'of the other key 1 '. Therefore, the transponder 2'of the other key 1 '
Does not emit its own key ID code signal radio wave 3 ′, and therefore the antenna coil 12 transmits the signal radio wave 3 ′.
′ 'Is received together with the regular signal radio wave 3 and mutual interference does not occur, and the engine can be smoothly started by the regular key 1.

[Brief description of the drawings]

FIG. 1 is a side view of one embodiment of the present invention.

FIG. 2 is a front view of the antenna used in the above embodiment.

FIG. 3 is an exploded perspective view of another example of the antenna used in the above embodiment.

FIG. 4 is a functional block diagram of a general immobilizer system.

FIG. 5 is a side view of a conventional immobilizer.

[Explanation of symbols]

 1,1 'key 2,2' transponder 3,3 'signal radio wave 4 immobilizer 7 key cylinder 8 key ring 10 antenna 11 bobbin 12 coil 13 core

Claims (1)

[Claims] 1. An immobilizer for receiving a key ID code signal radio wave transmitted from a transponder built in a key by an antenna for verification, and transmitting an engine stop command to an engine control unit when they do not match. An immobilizer in which the antenna for receiving the key ID code signal radio wave is attached to the upper half peripheral surface of the end of the key cylinder on the key insertion opening side.