JPS6092581A - Keyless entry system for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a keyless entry system for a vehicle that allows a door to be unlocked from a position away from the vehicle door.

[Prior art]

Conventionally, in vehicles such as automobiles, a locking mechanism is provided on the door to enable the door to be locked and unlocked, and the driver locks and unlocks the door using a key that matches the locking mechanism. There is. However, when getting in and out of a vehicle frequently, it is cumbersome to lock and unlock the doors each time. Further, at night, it is not easy to insert a key into the keyhole of the lock mechanism of the door in order to unlock the locked door.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to unlock an automobile door without operating a locking mechanism using a lock, and even from a location away from the vehicle.

〔Example〕

The present invention will be described below with reference to embodiments shown in the accompanying drawings.

In FIG. 1 showing the overall configuration, 10 is a key code transmitter that transmits a key code unique to each vehicle, and 11 is a transmitting antenna, both of which can be carried by the vehicle driver.

12 is a radio receiving antenna installed on the vehicle; 1
3 is a branching device that branches the output of the receiving antenna 12 according to the frequency band; 14 is a key code receiver; 15 is a car radio; 16 is a speaker for the car radio; and 17 is a door locking mechanism (not shown) when energized. This is a solenoid that unlocks the lock. All of these are installed in vehicles.

FIG. 2 is a block diagram mainly showing the detailed configuration of the key code transmitter 10 shown in FIG.
X (Frequency 5hift Keyin
22 is a high frequency FSX circuit connected to the antenna 11. Furthermore, in Figure 2, 23
24 is a battery, and when the switch 24 is closed, power is supplied to the circuits 20, 21, and 22.

FIG. 3 is a detailed diagram of the key code generation circuit 20 shown in FIG. 2, in which 40 is a one-chip microprocessor;
1 is its oscillation element. 42 is a select circuit for specifying a key code, and swO to SW4 are switches for specifying a key code according to their open/closed states.

The microprocessor 40 is programmed in advance to repeatedly execute the steps shown in FIG. 4 in order to generate a key code for each vehicle in accordance with the switch state of the key code designating select circuit 42. That is, the microprocessor 40 generates a stop bit 50 and a start bit 51 at a low level and a high level, respectively, for a predetermined period of time to synchronize the transmitter side and the receiver side, as shown in the output waveform diagram shown in FIG. Then, the open/close states of each of 5WO-3W4 of the designated key code designating select circuit 42 are sequentially output at high and low levels.

In the configuration on the transmitter side, when the vehicle driver closes the switch 24 of the key code transmitter 10 at hand near the vehicle, the key code generating circuit 20 A code signal 20a determined by the open/closed state of swo-sw4 previously set for each vehicle according to the program shown in the figure is output at the timing shown in FIG. In the timing chart of FIG. 5, for example, start bit 51. switch SW
Data bits 52 to 56 corresponding to O to SW4, respectively
The time width of each bit is 5 ms, and the stop pinot I.5
The number of 0s is the start, node 5I and data bit 52~
The number is 1 more than the sum of 56, and the cycle of repeating the program execution of the microcomputer 40 is 6.
It will be 5ms.

The signal 20a from the microcomputer 40 is input to the LL low frequency FSK circuit 21, and as shown in the timing chart of FIG.
When the signal 20a is at a high level of 00Hz, the signal 20a is frequency modulated to a frequency of 800H2, for example, and is input to the high frequency FSK circuit 22 as a signal 21a. In this high frequency FSK circuit 22, for example, if the signal 21a is at a low level as shown in FIG. 6. OOOMH2 is modulated to, for example, 76.075 MHz in the case of a high level, and a signal 22 having a frequency spectrum shown in FIG. 7 is transmitted by the antenna 11.
It is sent into the air as a radio wave.

Next, FIG. 8 is a block diagram mainly showing the detailed configuration of the key code receiver 14 shown in FIG.
A demodulation circuit, 31 is a low frequency FSX demodulation and code discrimination circuit, and 32 is a power amplification circuit. Also, 3 is the battery, 5
is a fuse.

FIG. 9 is a block diagram illustrating the configuration of the key code receiver 14 of FIG. 8 in more detail, in which 60 is a radio frequency amplification circuit, 61 is a mixing circuit, 62 is an intermediate frequency amplification circuit, 63 is an amplitude limiting circuit, 64 is an FM detection circuit, 65 is a low frequency amplifier circuit, 66 is a local oscillation circuit, 67 is a waveform shaping circuit, 68 is a microprocessor, 69 is an oscillation element, 70 is a transistor, 71 is a relay, and 72 is a select for specifying a key code. It is a circuit. Note that SW5 to SW9 are switches whose opening/closing states are predetermined in order to designate a key code for each vehicle that matches the key code designating select circuit 42 on the transmitter side shown in FIG. Also, microprocessor 6
8 is preprogrammed to repeatedly execute the steps shown in FIG.

In the configuration of the receiver mounted on the vehicle, the radio wave of the signal 22a propagates through the air from the antenna 11 on the transmitter side. The signal is branched into a signal going to the key code receiver 14 and a signal going to the key code receiver 14.Demodulation of the high frequency FSX in the key code receiver 14 is performed by the superheterodyne reception method, and the radio frequency signal manually inputted from the splitter 13 is split into a signal going to the key code receiver 14. It is amplified by the frequency amplification circuit 60, mixed with the continuous wave oscillated by the local oscillation circuit 66 by the mixing circuit 61, and converted into an intermediate frequency.
The signal is amplified by an intermediate frequency amplification circuit 62, passes through an amplitude limiting circuit 63, and is demodulated into a low frequency signal by an FMS detection circuit 64.

The demodulated low frequency signal is amplified by a low frequency amplifier circuit 65, shaped into the original rectangular wave by a waveform shaping circuit 67, and inputted to a microprocessor 68.

The microprocessor 68 demodulates the low frequency FSK according to the internally incorporated program shown in FIG. By producing a level output and turning on transistor 70, relay 71 is turned on and drives solenoid 17, thereby unlocking the door lock mechanism.

Note that the input impedance of the branching device 13 may be, for example, 80PF used in a normal car radio 15, the output impedance to the car radio 15 may be 80PF, and the output to the key code receiver 14 may be 75Ω or 50Ω. . In addition, the input impedance of the branch 13 is 75Ω or 50Ω, and the output impedance is also good for the car radio 1.
5. Both the key code receiver 14 may be 75Ω or 50Ω.

In the embodiments described above, the key code generation circuit 20 and further the low frequency FSK demodulation and code discrimination circuit 31 can be formed by a combination of logic gates, and the key code can be set by a diode or a programmable read-only memory.

〔Effect of the invention〕

As is clear from the above embodiments, according to the present invention, a vehicle driver can unlock a locked vehicle door simply by operating the switch of the oscillator that he or she owns near the vehicle. To easily unlock a vehicle door even when getting on and off the vehicle frequently or at night.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing the overall configuration of an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of the key code transmitter shown in FIG. 1, and FIG. 3 is a key code generator shown in FIG. 2. 4 is a flowchart for explaining the operation of the microprocessor shown in FIG. 3; FIG. 5 is a waveform diagram of an output signal generated by the microprocessor shown in FIG. 3; FIG. 6 is a signal waveform diagram for explaining the operation of the low frequency FSK circuit shown in FIG. 2, FIG. 7 is a frequency spectrum diagram for explaining the operation of the high frequency FSK circuit shown in FIG. FIG. 1 is a block diagram showing the configuration of the key code receiver shown in FIG. 1, FIG. 9 is an electrical wiring diagram showing the detailed configuration of the key code receiver shown in FIG. 8, and FIG. 10 is the microprocessor shown in FIG. 9. FIG. 2 is a flowchart for explaining the operation of FIG. 10.11... Transmitting means, 12.14... Receiving means. 17...Unlocking means. Representative Patent Attorney Takashi Okabe Figure 3 9A Figure 5 Figure 4 → Gingei Figure 9! 2 Figure 10

Claims (1)

[Scope of Claims] A key code generation circuit that generates a predetermined first key code signal by operating a switch, a digital frequency modulation circuit that modulates the key code signal with a low frequency digital frequency and further modulates it with a high frequency digital frequency, and a transmitting means that can be carried by a vehicle driver and includes a transmitting antenna for transmitting an output signal of the modulating circuit; A receiver mounted on a vehicle, comprising a demodulation circuit that demodulates a signal corresponding to an output signal to generate a received key code signal, and a circuit that detects a match between this received key code signal and a predetermined second key code signal. and an unlocking means for unlocking a door locking mechanism provided in the vehicle from a locked state in response to a signal indicating that the key code matches from the receiving means. .