JP3114509B2 - Anti-theft device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-theft device in which an engine of a vehicle cannot be started unless a key is used.

[0002]

2. Description of the Related Art Conventionally, some anti-theft devices for automobiles emit an alarm when a door is opened. However, automobiles that can be operated by directly connecting an engine starting circuit without a key must be stolen. There is. For this reason, there has been proposed a configuration in which the engine is not started unless a specific code signal incorporated in the key is received by a key cylinder by a key operation. Further, a mechanism for checking whether the specific code signal is correct or not on the key cylinder side even if the shape is the same is provided to prevent theft.

FIG. 7 shows such a key cylinder and key.
This will be described with reference to FIG. The light receiving element 2 and the magnet 3 are attached to the key cylinder 1, and the output of the light receiving element 2 is connected to the control circuit 4 so that an alarm and an engine start / stop signal are output. The key 5 includes a code generation circuit 6 and a light emitting element 7 for outputting the code.
Are provided, and a light emitting diode 8 indicating that light is being transmitted is attached. A battery 9 serving as a power source is exchangeably built in, and a magnetic switch 10 for turning on and off the power of the battery 9 is provided (Japanese Patent Application Laid-Open No. 62-173).
No. 354).

In this anti-theft device, when the key 5 is inserted into the key hole 1a of the key cylinder 1 and is set at a predetermined position, the magnetic switch 10 is turned on close to the magnet 3, and the code generation circuit 6 on the key side operates. , The light emitting diode 8 is turned on. The specific code signal output from the light emitting element 7 is input from the light receiving element 2 on the key cylinder side. The control circuit 4 determines whether the specific code signal is correct or not, and if it is not correct, determines that the lock is unlocked and issues an alarm.

[0005]

In the above-described anti-theft device, it is necessary to equip the key 5 with a battery 9. For this reason, many problems have occurred. That is,
In order to check the life of the battery 9, the brightness of the light emitting diode 8 must be checked, and a spare battery must always be prepared. If the life of the battery 9 has expired,
Since the specific code signal cannot be transmitted, even the authorized key 5 is unlocked improperly, and the driving of the automobile becomes impossible. Further, it is necessary to provide switch means (magnetic switch 10 and magnet 3) so as to supply power to the code generation circuit 6 when necessary. In addition, the battery replacement lid must be provided with a waterproof mechanism so that water does not splash on the battery. It is also necessary to facilitate replacement.

[0006] Therefore, a key satisfying the above conditions requires a high production cost. It is also inconvenient to carry around.

An object of the present invention is to provide an anti-theft device using a simple key in the operation of an automobile.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a key cylinder and key for an automobile.
ー Light source and light receiving element on cylinder side, solar cell on key side
And a light emitting element, wherein the key is the key cylinder.
Turn the ignition switch to the start position.
In the state, the light source and the solar cell, the light receiving element
The light emitting elements are positioned and fixed so as to face each other.
And the circuit switch of the light source is turned on.
Is set to, together with the set seen add code generation circuit to supply the solar cell to the key, to connect the output end of the code generation circuit to the light emitting element, provided in said key cylinder
Further, a control circuit for judging a specific code signal which is an output of a code generation circuit and operating an engine operating means or an alarm device is connected to an output terminal of the light receiving element.

[0009]

According to the present invention, a key is inserted into a key cylinder of an automobile and the key is rotated.
Key by aligning it with the “Start” position
The circuit switch of the light source on the cylinder side is turned on. Also,
The light source faces the solar cell, and the light receiving element faces the light emitting element.
You. Then, the light source illuminates the solar cell on the key side,
The electromotive force of the pond serves as the power supply for the code generation circuit in the key. light
The source is located close to the key cylinder, so the key cylinder
It is not necessary to improve other equipment provided in
You.

The code generation circuit is based on a solar cell.
Activated by power supply, generates specific code signal, emits light
A specific code signal is generated by the light receiving element on the key cylinder side.
Sent to Therefore, the key is a light emitting element
As long as the battery is facing, it can be manufactured as a mold type
Wear.

[0011] The light receiving element on the key cylinder side from the light emitting element on the key side.
The specific code signal sent to the optical element is sent to the control circuit
Can start the engine by matching
Therefore, the specific code signal is not received or
If the specified code signal does not match, the engine will start.
It does not happen and the alarm works.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG.
In some cases, a code generation circuit 6 is incorporated in a key 5, and a control circuit 4 for determining a specific code signal is provided in a key cylinder 1. The key cylinder 1 is connected to a main switch 13 that supplies electric power of a battery 12 to each circuit according to the rotation of the cylinder.

The control circuit 4 includes a main switch 13
Are connected, and the light receiving element 2 is connected to this input terminal. A light source 14, an alarm device 15, an engine control device 16, and a starter motor 17 are connected to each output terminal of the control circuit 4.

A code generation circuit 6 is provided inside the key 5, and a light emitting element 18 and a solar cell 19 are provided in a direction facing the key cylinder when the key 5 is inserted into the key hole 1a. Further, since these parts in the key do not need to be replaced, the key 5 is molded firmly and molded.

As shown in FIG. 4, around the key hole 1a of the key cylinder 1, the locking position of the key 5 is a position where the key 5 is inserted / removed: "Lock", and a position where only accessories are used:
“Acc”, the position during operation: “ON”, and the start position: “Start” are stamped. And key 5
The light receiving element 2 and the light source 14 are positioned such that the light emitting element 18 of the key 5 faces the light receiving element 2 and the solar cell 19 faces the light source 14 when the locking position of the key 5 is “Start”.

In order to prevent interference by light from the light source 14,
A filter that transmits near the emission wavelength of the light emitting element 18 is mounted on the front surface of the light receiving element 2, and a filter that blocks the vicinity of the emission wavelength of the light emitting element 18 is mounted on the front surface of the light source 14.

As shown in FIG. 2, the control circuit 4 on the key cylinder side includes an IG switch 20 in the main switch 13.
Is powered when is on. The IG switch 20 is turned on when the key position is "ON" or "Start". The ST switch 21 in the main switch 13 is turned on when the key position is "START". In addition, an infrared photodiode or the like is used for the light receiving element 2 and is connected to a demodulation circuit 22 in the control circuit 4. A lamp or the like is used for the light source 14 and “STAR” is set by the ST switch 21.
At the time of "T", the relay 23 is operated to light up.

A demodulation circuit 22 that tunes, amplifies, and detects a received light signal to demodulate a specific code is connected to a determination circuit 24. The determination circuit 24 is configured by a microcomputer or the like that determines whether or not the specific code signal is received and outputs an alarm and a start permission signal. The output of the determination circuit 24 is connected to the alarm device 15, the serial communication circuit 25, and the relay 26, respectively, and the serial communication circuit 25 transmits the engine control permission code signal output from the determination circuit 24 by serial communication.
26 operates when the start permission signal is turned on, and supplies electric power to the starter motor 17.

The electric power passing from the IG switch 20 through the power supply circuit 27 is converted into a constant voltage and supplied to each part of the control circuit 4. The reset circuit 28 outputs a reset signal until the output voltage of the power supply circuit 27 reaches a specified voltage, and releases the reset when the output voltage reaches the specified voltage.

Next, the code generation circuit 6 molded inside the key 5 will be described with reference to FIG. The output of the solar cell 19 is made a constant voltage by the power supply circuit 29. When the constant voltage falls below the specified voltage, the supply is stopped by the reset signal of the reset circuit 30.

The specific code signal basically has a specific frequency oscillated by the oscillation circuit 31, and this specific frequency is a modulation circuit.
32 and a frequency dividing circuit 33. The frequency dividing circuit 33 is connected to an address generating circuit 34 composed of a counter or the like and a serial pulse converting circuit 35. The address generation circuit 34 is first initialized by the reset circuit 30, and outputs the head address of the specific code signal. After that, the address is counted according to the frequency divided by the frequency dividing circuit 33, and when the address reaches the end address of the specific code signal, the address is reinitialized, and this is repeated.

The output of the address generation circuit 34 is input to a specific code storage circuit 36 composed of a ROM or the like. The specific code storage circuit 36 outputs a specific code signal according to the head address. The output of the specific code storage circuit 36 is input to a serial pulse conversion circuit 35 composed of a shift register or the like. After being initialized by the reset circuit 30, the serial pulse conversion circuit 35 converts the specific code signal into a serial pulse according to the frequency division frequency from the frequency division circuit 33,
Output to 32. The modulation circuit 32 modulates the serial pulse train of the specific code signal using the frequency from the oscillation circuit 31 as a carrier wave, and outputs the light from the light emitting element 18 including an infrared light emitting diode or the like.

Next, the operation of the control circuit 4 on the key cylinder side of the antitheft device will be described with reference to the flowchart shown in FIG. First, when the key 5 is inserted into the ON position, the IG switch 20 is turned on (step 1 (S
1)) At this time, the start permission signal and the alarm signal are off (S2). When the ST switch 21 is turned on by a key operation (S3), the light source 14 is turned on and the judgment circuit 2 is turned on.
4 is reset, the timer is initialized and started (S
4). In the determination circuit 24, the output signal of the demodulation circuit 22 is
Check to determine if a specific code signal is received
(S5).

While there is no light reception, the timer count value is checked (S9). If it is less than the specified value, the reception of a specific code signal is waited, and if it exceeds the specified value, an alarm signal is generated (S1).
0). Horn sound, headlight blinking as alarm means,
There is a wireless theft signal transmission and the like. After the ST switch 21 is turned on, power is supplied to the key 5, a specific code signal is transmitted from the light emitting element 18, and the specific code signal is transmitted to the determination circuit 24 via the light receiving element 2. Set the time to be longer than enough to be entered in.

If a specific code signal is detected, in step 6, the start permission signal is turned on and the alarm signal is turned off. The alarm signal is originally off, but it is assumed that the alarm is on in step 3, and the alarm is canceled. Further, the output of the ST switch 21 is supplied to the starter motor 17 to start the starter motor 17, and
Transmit the engine control permission code signal. Then, fuel injection, ignition and the like are operated according to this procedure, and the engine is operated. Unless the engine control permission code signal is output, even if the starter motor rotates and the crankshaft starts rotating due to improper operation such as direct connection of the battery, the engine will not start because control such as fuel injection and ignition does not occur. .

When the engine starts, the key 5 is turned "ON".
To the position. As a result, the ST switch 21 is turned off (S7), and the start permission signal is turned off (S8). As a result, the starter motor 17 stops, and the light source 14 turns off.

As described above, the use of the solar cell 19 as the power supply for the circuit inside the key eliminates the problem of running out of the battery. The display function becomes unnecessary. Even when the key 5 is housed in a key holder, energy is supplied by the light source 14 on the key cylinder side during use, so that it is convenient to carry.

In addition, as shown in FIG. 5, in a double-sided key (a key that can be inserted on either side) 5a, the light emitting element 18 and the solar cell 19 are mounted on both sides. Further, in the embodiment, the permission code and the alarm output from the control circuit 4 are transmitted to the engine control device 16 through serial communication (code),
Others are performed by signals (levels), but each output may be either. If the other party has a serial communication function, sending it by code can cope with illegal operations more strongly. The specific code signal transmitted by the key 5 may be a predetermined signal, or the ST switch may be set according to a rule preset by the key 5 (code generation circuit 6) and the control circuit 4 (judgment circuit 24). A code system that changes each time 21 is turned on may be used.

[0029]

According to the present invention, since the anti-theft device comprising a structure with a key and key cylinder as described above, key
If the key is not set to the Start position, the solar cell on the key side
Is supplied with energy from the light source on the key cylinder side.
And the code generation circuit inside the key does not work.
No signal is generated. Therefore, the key cylinder side
Since there is no signal input to the control circuit,
This will prevent theft of the car.
You. In the Start position, every time the engine is started
Cars are illegally operated to communicate specific code signals
Each time you try to turn,
You have to work on it,
Effective for preventing difficulties. Further, the key does not require battery replacement as compared with the conventional example, so that the circuit portion can be completely molded, and the disconnection of the circuit can be reinforced and waterproofed. Also, you can eliminate the hassle of carrying the key,
The spread of the key can be increased.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an anti-theft device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a control circuit of the anti-theft device shown in FIG.

FIG. 3 is a block diagram illustrating a code generation circuit of the anti-theft device shown in FIG. 1;

FIG. 4 is a front view of a key cylinder of the antitheft device shown in FIG. 1;

FIG. 5 is a sectional view showing a modification of the key of the anti-theft device shown in FIG. 1;

FIG. 6 is a flowchart illustrating a system of the anti-theft device shown in FIG. 1;

FIG. 7 is a configuration diagram illustrating a key cylinder of a conventional anti-theft device.

FIG. 8 is a cross-sectional view illustrating a key of a conventional anti-theft device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Key cylinder 2 Light receiving element 4 Control circuit 5 Key 6 Code generation circuit 14 Light source 15 Alarm device 18 Light emitting element 19 Solar cell 21 Light source circuit switch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI G08B 13/00 G08B 13/00 B H01L 31/04 H01L 31/04 Q

Claims (1)

(57) [Claims] 1. A key cylinder and a key of an automobile,
Light source and light receiving element on the key cylinder side, solar power on the key side
A key and an ignition switch of the key cylinder.
With the light source stopped at the start position of the
The solar cell, the light receiving element and the light emitting element are respectively
Positioned and fixed to face each other, and the light source
Is set such that the circuit switch is turned on, a code generator to power the solar cell to the key
With the set seen Add, connects the output end of the code generation circuit to the light emitting element, wherein the output end of the light receiving element provided in the key cylinder, the the determination of the specific code signal which is the output of the code generator engine An anti-theft device to which a control circuit for operating an activating means or an alarm device is connected.