JPH1099105A - Key ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a key ring preventing unnecessary electromagnetic coupling with a transponder, which causes interference of a code or the like to the other keys attached to the same key ring. SOLUTION: A conductor plate 25 is installed between the keys 21-23 on a key ring 20 so that the transponders 22b, 23b except for a key 21 inserted into a key cylinder 26, are not electromagnetically coupled with an antenna coil 27 of the key cylinder 26, when the key 21 is inserted into a key cylinder 26. By this structure, the transponder 21a of the key 21 is electromagnetically coupled with the electromagnetic wave applied from the antenna coil 27 side properly, but the electromagnetic wave to the transponders 22b, 23b of the other keys are shielded by the conductor plate, and the unnecessary electromagnetic coupling can be effectively prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key ring provided with a plurality of keys including an electromagnetically coupled transponder for performing code communication with communication means mounted on a vehicle or the like.

[0002]

2. Description of the Related Art As is well known, in a vehicle such as an automobile, a driver usually inserts a key into a key cylinder of the vehicle, and a predetermined key operation is performed to start an engine of the vehicle and run the vehicle. It is possible.

However, such a key is generally capable of performing the above-described key operation as long as a groove formed in a metal portion of the key matches a groove of a key cylinder into which the key is inserted. Therefore, theft of the vehicle by a so-called forged key in which the groove formed in the key metal part is forged has occurred to a considerable extent.

Therefore, in addition to such a mechanical key system, code communication by amplitude modulation or the like is performed with an electromagnetically coupled transponder (automatic transponder) mounted on the key in advance, and the responded identification code is transmitted. An anti-theft device that enables the vehicle to start under the condition that the vehicle is appropriate has been proposed and put into practical use. FIG. 2 shows an example of a conventional immobilizer system.

The immobilizer system illustrated in FIG. 2 has a transponder 2 built in a grip portion of a key 1.
And the transponder 2 through an antenna coil 4 wound around a key cylinder 3 into which the key 1 is inserted.
And a control circuit 9 for controlling the operation of the transmitting / receiving circuit 8.

As shown in FIG. 3, the transponder 2 includes a coil 31 to which a magnetic field BD generated from the antenna coil 4 is applied, a resonance circuit including a capacitor 32 electrically connected in parallel to the coil 31, and And a response circuit 33 that responds to an inquiry from the transmission / reception circuit 8 based on a resonance signal from the resonance circuit. FIG. 4 shows an electrical configuration of the transponder 2 including the response circuit 33.

As shown in FIG. 4, the transponder 2 rectifies the electric power induced by the electromagnetic coupling between the antenna coil 4 and the coil 31 in a rectifier circuit 33a in a response circuit 33, and Communication power to the communication circuit 3
3b, power is supplied to the control circuit 33c and the EEPROM 33d, respectively, and the predetermined operation for responding to the identification code is automatically executed.

In the response circuit 33, a communication circuit 33
b: (1) A code (identification code) given from the control circuit 33c is modulated in a predetermined manner and sent out from the coil 31 (resonance circuit). (2) The transmission code received from the transmission / reception circuit 8 via the coil 31 is demodulated and transmitted to the control circuit 33c.
Give to. Is performed.

The control circuit 33c reads (1) the identification code stored in the EEPROM 33d based on the power supply and
b. (2) The identification code stored in the EEPROM 33d is updated (overwritten) by the code demodulated through the communication circuit 33b. Circuit. Incidentally, the control circuit 33c assumes a rolling code system in which the identification code is changed each time the key 1 is inserted into the key cylinder 3.

As shown in FIG. 2, when the key 1 is inserted into the key cylinder 3 by the driver, the control circuit 9 recognizes the insertion of the key 1 via the key unlock warning switch (key presence / absence switch) 12. , And starts reading the identification code based on the recognition. In reading this identification code, as described above, the key 1
Power is supplied to the transponder 2 by electromagnetic coupling. As a result, the EEPROM 33 of the transponder 2
The identification code read from d is input to the transmission / reception circuit 8. The transmitting / receiving circuit 8 demodulates the input identification code in a predetermined manner and outputs the demodulated code to the control circuit 9. The process of reading the identification code is performed using the time from when the key 1 is inserted until the key 1 is operated to the starter position (about 100 ms (millisecond) of the time). .

When the identification code is read in this way, the control circuit 9 and the read identification code and the EEP
By comparing the identification code with a code registered in the ROM in advance, it is determined whether or not the identification codes match.

As a result of this determination, if the identification codes do not match because the key 1 is the forged key or the like, the control circuit 9 issues a code for instructing the engine control device 10 to prohibit starting the engine. Is output. Accordingly, the operation of the igniter, the injector, and the fuel pump through the engine control device 10 is prohibited.

On the other hand, if the result of the above determination is that the identification codes match, the control circuit 9 outputs a code for instructing the engine control device 10 to permit the start of the engine (starting the engine). Issue a permit) and perform the change of the identification code for the rolling code.

When the start permission is issued, the control of the igniter, the injector, and the fuel pump through the engine control device 10 is started, and the vehicle is ready to run. Other conditions for issuing the start permission include that the door is closed, that the key unlock warning switch 12 indicates that a key is present, and that the ignition switch 11 (FIG. 2) is IG-ON. And other conditions are usually included.

[0015]

By the way, a plurality of keys 1 including the above-mentioned transponder 2 are usually prepared including spares for lost or the like, and all the keys 1 are attached to the same key ring. ing. Before shipment from the factory, it is necessary to perform an engine start inspection on all keys including the spare key attached to the key ring.

However, as described above, the transponder 2 only transmits a predetermined power by electromagnetic coupling to the transponder 2 built in the key 1 so that the transponder 2 transmits the stored identification code. Has become.

For this reason, for example, as shown in FIG. 5, when two other keys 1a and 1b are attached to the same key ring 5, there is a possibility that the transponders 2a and 2b may cause interference. That is, in this case, the magnetic field BD generated from the antenna coil 4
As well as the transponder 2 of the additional keys 1a and 1b
a and 2b, and the transponders 2a and 2b may simultaneously respond to the identification code. Incidentally, when two or more identification codes are responded and superimposed as described above, a desired identification code cannot be obtained, and the above-described inconsistency of the identification codes cannot be achieved. .

As a result, a plurality of keys 1,
When 1a and 1b are attached, these keys 1,
Engine start-up inspections according to 1a and 1b are very difficult and unreliable.

The present invention has been made in order to solve the above-mentioned problem, and by appropriately preventing electromagnetic coupling of a key other than a key inserted into a key cylinder attached to the same key ring with a transponder, the present invention has been made. It is an object of the present invention to provide a key ring capable of reliably performing start-up inspection of a plurality of keys attached to the key ring and greatly improving reliability.

[0020]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a key having a built-in electromagnetically coupled transponder for performing code communication with communication means mounted on a vehicle or the like. In a plurality of attached key rings, electromagnetic shielding means is provided on the key ring so as to be interposed between the keys.

According to a second aspect of the present invention, in the first aspect of the present invention, when the electromagnetic shielding means overlaps with a key, the electromagnetic shielding means is formed to have substantially the same size as a grip portion containing a transponder, and covers the transponder. To be covered.

According to a third aspect of the present invention, in the first aspect of the present invention, the electromagnetic shield means is formed of an aluminum plate. According to the first aspect of the present invention, by providing the electromagnetic shielding means, the transponder mounted on the key that is not inserted into the key cylinder is shielded from the electromagnetic waves by the electromagnetic shielding means. It will not respond.

According to the second aspect of the present invention, the size of the electromagnetic shielding means is substantially the same as that of the grip portion.
The entire key ring does not become bulky and the weight can be reduced.

According to the third aspect of the present invention, the electromagnetic shielding means is formed of an aluminum plate having excellent conductivity.
Electromagnetic waves can be more reliably blocked, and the weight of the entire key ring can be reduced.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. As shown in FIG. 1, the key ring 20 is provided with three ignition keys 21 to 23 provided for one automobile. Each key 21 to 23 has its grip portion 21a to 23
The transponders 21b to 23b are respectively incorporated in a. The key ring 20 has three conductive plates 2 made of an aluminum plate as electromagnetic shielding means so as to be interposed between the ignition keys 21 to 23, respectively.
5 is attached. The conductive plate 25 is provided for each of the keys 2.
Each of the grip portions 21a to 23a has a square shape having substantially the same outer shape as that of the grip portions 21a to 23a, and a hole 25a to be hooked on the key ring 20 is formed at a corner thereof. When the conductive plate 25 overlaps with the grip portions 21a to 23a, the conductive plate 25 completely covers the transponders 21b to 23b built in the grip portions 21a to 23a.

That is, for example, when one key 21 is inserted into the key ring 26, the remaining keys 22 and 23 attached to the key ring 20 hang downward with respect to the key 21 via the key ring 20. . At this time, the three conductive plates 25 are also suspended so as to overlap with the grip portions 22a and 23a of the keys 22 and 23.

Next, a plurality of keys 2 constructed as described above
Key ring 2 with 1 to 23 and conductive plate 25
The function and effect of 0 will be described. When the key 21 is inserted into the key ring 26 for starting the engine, the remaining keys 22 and 23 hang downward via the key ring 20. A conductive plate 25 is provided outside the keys 22 and 23, respectively.
b, 23b. That is, the transponders 22b and 23b of the keys 22 and 23 are electromagnetically cut off by the conductive plate 25 made of an aluminum plate.

Therefore, electromagnetic waves based on communication between the transponder 21b of the key 21 inserted into the key ring 26 and the antenna coil 27 provided on the key cylinder 26 are completely blocked by the conductive plate 25.
Transponders 22b and 23b of keys 22 and 23
Is very unlikely to be erroneously operated, and there is no risk of interference due to erroneous operation. As a result, the engine start inspection operation in the immobilizer system can be efficiently performed while the plurality of keys including the transponder are attached to the key ring.

In the present embodiment, the conductive plate 25
Is not a size that covers the entire keys 21 to 23, but is substantially the same as the outer shape of the grip portions 21a to 23a. Therefore, the key ring 20 is not bulky and can be reduced in weight.

Further, in the present embodiment, since the conductive plate 25 is formed of an aluminum plate having excellent conductivity, the electromagnetic wave can be more reliably cut off and the key ring 20 can be formed.
The overall weight can be reduced.

The present invention is not limited to the above embodiment, but may be implemented as follows. (1) In the above embodiment, the conductive plate 25 as the electromagnetic shielding means is formed of an aluminum plate, but may be formed of a conductive plate such as an iron plate. Further, if the electromagnetic shielding means is to shield electromagnetic waves, aluminum foil or a conductor obtained by knitting a conductive wire in a net shape may be formed into a sheet shape with a synthetic resin or the like. (2) In the above embodiment, the hole 25a formed in the conductive plate 25 is formed at the corner, but may be formed at the center of the upper side. Alternatively, a long hole along the upper side of the conductive plate 25 may be used.

[0032]

As described above in detail, according to the present invention, even when a plurality of keys are attached to a key ring, the transponders of the keys other than the key inserted into the key cylinder are electromagnetically connected to the antenna coil of the key cylinder. Since the coupling is accurately prevented, the reliability of the engine start inspection at the time of shipment can be greatly improved for all of the keys attached to the key ring.

[Brief description of the drawings]

FIG. 1 shows one embodiment of the present invention (a).
Front view, (b) Side view.

FIG. 2 is a system configuration diagram showing a system configuration as a vehicle anti-theft device.

FIG. 3 is an explanatory diagram illustrating an internal structure of a key including a transponder.

FIG. 4 is a block diagram showing an electrical configuration of the transponder.

FIG. 5 is an explanatory diagram illustrating an interference mode when an additional key is present in the key ring.

[Explanation of symbols]

20 ... key ring, 21, 22, 23 ... key, 21a,
22a, 23a ... key grip portions, 21b, 22b,
23b: transponder, 25: conductive plate, 25a
... holes formed in the conductive plate, 26 ... key cylinder, 2
7. Antenna coil.

Claims (3)

[Claims] An electromagnetically coupled transponder for performing code communication with communication means mounted on a vehicle or the like.
A key ring including a plurality of keys (21 to 23) including a built-in key (23b);
A key ring, wherein an electromagnetic shield means (25) is provided so as to be interposed therebetween. 2. The transponder (2) when the electromagnetic shielding means (25) overlaps the keys (21 to 23).
1b to 23b) built-in grip portions (21a to 23a)
The transponder (2) which is formed in the same size as
The key ring according to claim 1, which covers over 1b to 23b). 3. The key ring according to claim 1, wherein said electromagnetic shielding means (25) is an aluminum plate.