JP3979910B2 - Immobilizer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an immobilizer for discriminating whether an ignition key is unique to the vehicle by transmitting and receiving to / from a transponder built in the ignition key and preventing the vehicle from being stolen.
[0002]
[Prior art]
Along with the recent increase in vehicle theft incidents, immobilizers that increase the anti-theft effect by recognizing the identity of the authentication code in addition to recognizing the identical shape of the key shape of the ignition key and the key hole (For example, refer to Patent Document 1). Patent Document 1 discloses a technique for collating an authentication code by winding a coil as an antenna around the tip of an ignition switch and performing wireless communication between the antenna and a transponder built in an ignition key. Has been.
[0003]
In addition, there is also a type in which a part around which a coil as an antenna is wound and a part that accommodates a circuit to be connected to the antenna are integrally formed and arranged on the ignition switch of the vehicle ( For example, see Patent Document 2). According to the immobilizer disclosed in Patent Document 2, the dimension between the antenna and a circuit connected to the antenna can be shortened, and the authentication code can be transmitted and received more reliably.
[0004]
[Patent Document 1]
JP 2002-87368 A (column of embodiment of the invention, FIG. 3)
[Patent Document 2]
Japanese Patent Laid-Open No. 10-81203 (column of embodiment of the invention, FIGS. 1 to 3)
[0005]
[Problems to be solved by the invention]
However, the conventional immobilizer has the following problems. That is, in the immobilizer disclosed in Patent Document 1, since the coil as an antenna is wound around the tip of the ignition switch, when the immobilizer is newly installed on the existing vehicle, the ignition switch is also replaced. There was a problem that the installation cost would increase.
[0006]
On the other hand, according to the immobilizer disclosed in Patent Document 2, the ignition switch, the antenna, and the circuit to be connected to the antenna are separated from each other. The part where the coil is wound and the part accommodating the circuit to be connected to the antenna are formed apart from each other, and it takes time to connect the wiring connecting them, and the wiring may be disconnected. There was a problem.
[0007]
The present invention has been made in view of such circumstances, and an immobilizer that can suppress the installation cost and avoid disconnection of the wiring connecting the antenna and the circuit to be connected to the antenna. Is to provide.
[0008]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided an antenna capable of transmitting and receiving to and from a transponder built in an ignition key, connected to the antenna, driving the antenna at a high frequency and demodulating a code signal received from the transponder. A high-frequency circuit for obtaining a personal identification code, a personal identification code demodulated by the high-frequency circuit and a personal identification code stored in advance, and a control circuit that permits engine start of the vehicle only when they match, In an immobilizer having a circuit board on which a high-frequency circuit is formed, a through-hole for inserting an ignition key is formed with a key hole of a cylinder lock formed on an ignition switch of a vehicle facing upward, and the cylinder lock A case that can be disposed on the top of the circuit board, and the antenna on the circuit board. Accommodates the antenna and the circuit board in the casing at constant differential allowed state, it is arranged in a state where the antenna is surrounded the through-hole, and, the casing is connected to the circuit board of the immobilizer It is characterized by comprising display means for displaying the operation status .
[0009]
According to a second aspect of the present invention, in the immobilizer according to the first aspect, the circuit board has a hole through which an ignition key can be inserted, and a coil constituting the antenna is disposed along the periphery of the hole. It is characterized by that.
[0010]
According to a third aspect of the present invention, in the immobilizer according to the first or second aspect, a resin is filled in the case in which the antenna and the circuit board are accommodated.
[0012]
According to a fourth aspect of the present invention, in the immobilizer according to any one of the first to third aspects, the control circuit is formed on the circuit board.
[0013]
According to a fifth aspect of the present invention, in the immobilizer according to the second aspect, a magnetic body is disposed along the periphery of the hole of the circuit board.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
The immobilizer according to the present embodiment is for determining whether the ignition key is unique to the two-wheeled vehicle by transmitting / receiving to / from a transponder built in the ignition key, and for preventing theft of the two-wheeled vehicle. Yes, as shown in FIGS. 1 and 2, it is mainly composed of a case 1, a circuit board 2, an antenna 5, and a magnetic body (ferrite) 6.
[0015]
As shown in FIG. 2, the case 1 can be disposed at the upper part of the cylinder lock 3a with the key hole 3b of the cylinder lock 3a formed at the upper part of the ignition switch 3 of the vehicle facing upward. As shown in FIG. 1, various characters and symbols for indicating the position and operation direction of the ignition key are marked on the upper surface, and a through hole 1a for inserting the ignition key is formed in the approximate center.
[0016]
Further, flange portions 1b are formed so as to protrude from both sides of the case 1, and screw holes 1c into which screws can be screwed are formed on the back side of each flange portion 1b. However, the case 1 can be fixed to the two-wheeled vehicle by projecting a screw from the upper bracket of the two-wheeled vehicle and screwing the screw into the screw hole 1c.
[0017]
Further, an LED 4 (display means) connected to the circuit board 2 is arranged on the upper surface of the case 1 so as to display the operation status of the immobilizer. Specifically, this LED 4 is lit to turn on when the immobilizer is being authenticated (verifying whether or not the ignition key inserted into the key hole 3b is unique to the two-wheeled vehicle). It is configured to inform the operation status of the immobilizer.
[0018]
The case 1 is open on the back side to form an accommodation space therein. The circuit board 2, the antenna 5 formed of a coil, and the annular magnetic body 6 are accommodated in the accommodation space. Among these, the antenna 5 can transmit and receive a predetermined signal to and from the transponder T (see FIG. 5) built in the ignition key IK and wirelessly communicate with the transponder. It is fixed on the top.
[0019]
Here, the housing space in which the circuit board 2, the antenna 5, and the magnetic body 6 are housed is filled with resin 11 and molded, and the wiring connecting the antenna and the high-frequency circuit on the circuit board is disconnected. Can be avoided more reliably, and foreign matter, rainwater, and the like can be prevented from entering the circuit board 2. Further, since the annular magnetic body 6 and the antenna 5 are arranged along the periphery of the hole 2a of the circuit board 2, the ignition key IK is inserted between the key hole 3b and the transponder T and the antenna 5 between them. The size of the signal can be shortened, and signals can be transmitted and received between them more accurately and reliably.
[0020]
The transponder T built in the ignition key IK operates based on a radio signal transmitted from the antenna 5 and transmits a signal as a response to the radio signal to the immobilizer side. As shown in FIG. 6, the transponder T includes an antenna 12 for receiving a radio signal transmitted from the immobilizer side and transmitting information generated on the transponder T side, and a high frequency for demodulating the received radio signal. A circuit 13, an authentication key generation IC 14 for controlling the transponder T, an EEPROM 15 including non-volatile storage means for storing information unique to the ignition key IK, and a capacitor 16 corresponding to a secondary battery are provided.
[0021]
By the way, the circuit board 2 is disposed over substantially the entire accommodation space of the case 1 in a plan view, and has a hole 2a through which the ignition key IK can be inserted, as shown in FIG. Circuits such as a high-frequency circuit 7 and an LED drive circuit 9 are formed on the side (see FIG. 4). That is, as shown in the figure, the antenna 5 is connected to a control circuit 8 outside the case 1 via a high-frequency circuit 7, and the external control circuit 8 is connected to the LED drive circuit 9 on the circuit board 2 and the case 1. It is connected to an external EEPROM 10 and electrically connected to an ECU for controlling the motorcycle engine.
[0022]
The high frequency circuit 7 is a circuit for driving the antenna 5 at a high frequency and demodulating the code code signal received from the transponder T to obtain a code, and the obtained code is sent to the control circuit 8. The control circuit 8 comprises arithmetic means such as a CPU, compares the code code sent from the high-frequency circuit 8 with the code code stored in the EEPROM 10 in advance, and permits the engine start of the motorcycle only when they match. It is controlled as follows.
[0023]
The LED drive circuit 9 is connected to the control circuit 8 and is used to light or blink the LED 4 in accordance with the operation status of the immobilizer. In the present embodiment, the LED 4 is provided in the case 1 and the LED 4 is lit or blinked by the LED drive circuit 9. However, the LED 4 is disposed on the meter panel of the two-wheeled vehicle as in the prior art, and lit or blinks there. The driver may be informed of the operation status of the immobilizer.
[0024]
Next, the operation of the immobilizer having the above configuration will be described.
When the ignition key IK is inserted into the key hole 3b of the cylinder lock 3a through the hole 1a of the case 1 and turned to the operating position (on position), the ignition switch 3 is turned on and power is supplied to the immobilizer so that the immobilizer operates. Start. When the immobilizer starts to operate, various initial settings such as generation of start time data are performed, and then the control circuit 8 generates random number data based on the start time data.
[0025]
Subsequently, transmission data for transmission from the high frequency circuit 7 to the transponder T in the ignition key IK is generated. Such transmission data is wirelessly transmitted from the high-frequency circuit 7 to the antenna 12 of the transponder T via the antenna 5 and demodulated by the high-frequency circuit 13 disposed in the ignition key IK. At the same time, the high-frequency circuit 13 in the ignition key IK generates an authentication key based on the transmission data. The authentication key is obtained by encrypting random number data using an encryption key that is information unique to the ignition key IK stored in the EEPROM 15.
[0026]
Then, the generated authentication key is transmitted to the immobilizer side via the high-frequency circuit 13 and the antenna 12 of the transponder T, and the control circuit 8 compares it with an authentication code separately generated on the immobilizer side. This authentication code is obtained by encrypting random number data using an encryption key that is information unique to the ignition key IK stored in the EEPROM 10.
[0027]
When the authentication code matches the authentication key, the control circuit 8 transmits a signal permitting engine start to the ECU. That is, the engine of the two-wheeled vehicle can be started only when the ECU receives this signal. In this way, in addition to recognizing the identical shape of the key shape of the ignition key IK and the shape of the key hole 3b, the engine start of the motorcycle is permitted by recognizing the same electronic authentication code. The anti-theft effect can be remarkably enhanced.
[0028]
According to the immobilizer according to the present embodiment, although the magnetic body 6 is interposed, the antenna 5 and the circuit board 2 can be accommodated in the case 1 in a state where the antenna 5 is fixed on the circuit board 2. Therefore, the antenna 5 and the circuit board 2 can be brought extremely close to each other, and disconnection of the wiring connecting them can be effectively suppressed.
[0029]
Although the present embodiment has been described above, the present invention is not limited to this. For example, the shape and size of the case 1 can be arbitrarily changed according to the two-wheeled vehicle, and the LED 4 as the display means can be used. Instead, other light emitting means such as a lamp may be used. Moreover, in this embodiment, although the immobilizer is provided above the ignition switch of the two-wheeled vehicle, it may be provided in another vehicle such as an automobile.
[0030]
In addition, substantially all of the components (including the control circuit 8 and the EEPROM 10) constituting the immobilizer may be accommodated in the case 1. Further, the control circuit is not limited to the one that performs the operation of the above-described embodiment, but compares the code code demodulated by the high-frequency circuit with the code code stored in advance, and the vehicle engine only when they match. It would be enough to allow starting. That is, without using complicated encryption processing or random number data, the engine start permission signal may be transmitted simply by comparing the encryption code on the ignition key IK side with the encryption code stored in advance on the immobilizer side. .
[0031]
【The invention's effect】
According to the invention of claim 1, since the antenna and the circuit board are accommodated in the case while the antenna is fixed on the circuit board, the components constituting the immobilizer and the ignition switch are separated from each other. The new installation cost can be reduced, the antenna and the circuit board can be brought into close proximity or contact with each other, and the wiring connecting the antenna and the circuit to be connected to the antenna can be easily connected. In addition, disconnection of the wiring can be avoided.
In addition, since the display means for displaying the operation status of the immobilizer is provided in the case, it is possible to install an immobilizer in an existing vehicle as compared with the conventional one in which the display means is provided in a meter panel or the like. This makes it easy to control the cost of new installation.
[0032]
According to the invention of claim 2, since the hole through which the ignition key can be inserted is formed in the circuit board and the coil is arranged along the periphery of the hole to constitute the antenna, the ignition key is The dimension between the transponder and the antenna can be shortened in the state of being inserted through the key hole, and transmission / reception of signals between them can be performed more accurately and reliably.
[0033]
According to the invention of claim 3, since the resin is filled in the case in which the antenna and the circuit board are accommodated, it is possible to more reliably avoid disconnection of the wiring connecting the antenna and the high frequency circuit on the circuit board. It is possible to prevent foreign matter and rainwater from entering the circuit board.
[0035]
According to the invention of claim 4, since the control board is formed on the circuit board in addition to the high-frequency circuit, the high-frequency circuit and the control circuit can be arranged closer to each other, and the wiring that connects them can be routed. Can be simplified and wire breakage can be prevented.
[0036]
According to the invention of claim 5 , since the magnetic body is disposed along the periphery of the hole of the circuit board, the magnetic body can effectively assist the radio wave of the antenna.
[Brief description of the drawings]
FIG. 1 is a top view of an immobilizer according to an embodiment of the present invention as viewed from above a case. FIG. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 4 is a block diagram for illustrating an immobilizer according to an embodiment of the present invention. FIG. 5 is a schematic diagram for illustrating an ignition key applied to the immobilizer according to the embodiment of the present invention. Block diagram showing the transponder built in the ignition key applied to the immobilizer according to
DESCRIPTION OF SYMBOLS 1 ... Case 2 ... Circuit board 2a ... Hole 3 ... Ignition switch 3a ... Cylinder lock 3b ... Key hole 4 ... LED (display means)
5 ... Antenna 6 ... Magnetic body 7 ... High frequency circuit 8 ... Control circuit 9 ... LED drive circuit 10 ... EEPROM
DESCRIPTION OF SYMBOLS 11 ... Resin 12 ... Antenna 13 ... High frequency circuit 14 ... Authentication key generation IC
15 ... EEPROM
16 ... Capacitor IK ... Ignition key T ... Transponder

Claims (5)

An antenna capable of transmitting and receiving to and from the transponder built in the ignition key;
A high-frequency circuit connected to the antenna, driving the antenna at a high frequency and demodulating a code signal received from the transponder to obtain a code.
A control circuit that compares the code code demodulated by the high-frequency circuit with the code code stored in advance, and permits the engine start of the vehicle only when they match,
A circuit board on which at least the high-frequency circuit is formed;
In immobilizer with
A circuit board having a case in which a key hole of a cylinder lock formed in an ignition switch of a vehicle faces upward and a through hole for inserting the ignition key is formed and can be disposed at an upper portion of the cylinder lock; in a state of fixing the antenna to the top accommodates the antenna and the circuit board in the casing, is disposed in a state in which the antenna is surrounded the through-hole, and, in the case, and the circuit board An immobilizer comprising display means connected to display an operation status of the immobilizer.   2. The immobilizer according to claim 1, wherein the circuit board has a hole through which an ignition key can be inserted, and a coil constituting the antenna is disposed along the periphery of the hole.   The immobilizer according to claim 1 or 2, wherein a resin is filled in the case in which the antenna and the circuit board are accommodated. The immobilizer according to any one of claims 1 to 3 , wherein the control circuit is formed on the circuit board.   The immobilizer according to claim 2, wherein a magnetic material is disposed along a peripheral edge of the hole of the circuit board.

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