JPH0726495B2 - Keyless entry device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a keyless entry device for controlling the opening and closing of doors and trunks of automobiles by radio waves. In particular, the invention relates to a keyless entry device that utilizes a difference in propagation characteristics between two types of frequencies. It is possible to open and close the door and the trunk separately by operating a button.

[Conventional technology]

In the keyless entry system, which uses a radio wave from outside the vehicle to remotely open and close the locks on the doors and trunks of automobiles, the doors are opened or closed from the transmitters that people have, or the trunks are opened. A code for expressing the operation and a carrier wave modulated with a specific code (recognition number) corresponding to the tooth profile of the key are transmitted. When the receiver mounted on the car receives the transmitted radio wave, it determines whether the identification number matches that on the receiver side, and if so, it determines the code indicating the operation command, and controls necessary for operation. It outputs a signal to drive an actuator for opening and closing the lock on the trunk or door.

In such a system, the transmitter is usually provided with a switch for opening the door lock, a switch for closing the door lock, and a switch for opening the trunk lock, and each switch is operated by operating a unique switch. Send the code to open and close the car door and trunk lock.

[Problems to be solved by the invention]

However, in the above-described system, a person has to select which switch to press, which is likely to cause an erroneous operation. The present invention aims to improve this point by unifying the operation switch. In this case, regarding the remote control range, when the person with the transmitter is separated from the car, it is desirable to be able to operate from the entire circumference of the car in order to open the door for other people to get in, Considering that it is sufficient for the operator to operate the trunk in the vicinity of the trunk, the doors can be opened and closed from around the vehicle, and the trunk can be opened only when the transmitter is operated near the trunk. A keyless entry system is required.

[Means for solving problems]

The present invention relates to a keyless entry device for transmitting or receiving electric waves from a transmitter outside a vehicle to a receiver on the vehicle side to open or close a lock of a door or a trunk of the vehicle, and a single switch operation from the transmitter. At the same time, high and low frequency radio waves are simultaneously transmitted, and the receiver controls the opening of the trunk lock when both radio waves are received at a predetermined level or higher, and the door lock when only high frequency radio waves are received at a predetermined level or higher. The opening and closing control is performed.

[Action]

Tens of MHz if the receiving antenna is installed in the car
When radio waves of high frequency are used, it is easy to extend the remote control range to the entire circumference of the vehicle. However, it is quite difficult to give directivity only to a specific place by using the same frequency band, and to be able to operate only near the trunk, for example. Since the size of the car body is close to the wavelength of several tens of MHz, the car body that should be a ground plate is excited and re-radiates to the original antenna element, or the excited car body is used as an antenna element whose ground is the ground. It is speculated that it works. For this reason, the vehicle is not uniform over the entire circumference of the vehicle but has sensitivity, and the trunk is opened even in other places. However, if the frequency is selected to be several hundreds of KHz, the arrival isolation becomes short, but the propagation characteristics that the vehicle body is less affected (the vehicle body functions as a ground plate) make the antenna sensitive to only one direction. It will be easy to give.

FIG. 1 is an explanatory view of this, in which (a) shows an isoelectric field line of 60 MHz and (b) shows an isoelectric field line of 500 KHz. In the figure, 1 is a vehicle body, 2 is a door, 3 is a trunk, 4 is a 60 MHz band antenna, and 5 is a 500 KHz band antenna. The antenna 4 can be shared with, for example, an FM band radio antenna (glass antenna, rod antenna). The antenna 5 is, for example, a coil wound around a ferrite bar, and is attached to, for example, a rear bumper.

Using the characteristics of (a) and (b) described above, 60MHz and 500KHz
, The door 2 is controlled to open and close when only 60MHz is received above a predetermined level, and the trunk 3 is opened when both 60MHz and 500KHz are received above a predetermined level. The trunk control area is wide and narrow as shown in (c) 6 and 7, and the door 2 can be opened and closed from all directions, but the trunk 3 can be opened only when approaching rearward.

〔Example〕

FIG. 2 is a block diagram showing an embodiment of the present invention, in which (a) is a transmitter and (b) is a receiver. Transmitter 8 operates by pressing a single transmit button (switch) 81 60MHz (f ₁ ) and 500KH
Oscillation circuit 82 of z (f ₂ ) self-excited or using crystal oscillator,
It has 83 and transmits radio waves of each frequency from antennas 84 and 85. However, its output is very weak, 15μV / m at 100m ahead.
It is of a degree. This transmitter-specific identification code is easier to detect if it is modulated on the side of f _{1 where the} reception area is wide. 86 is a code generator for this purpose.

The receiver 9 has receivers 90 and 91 for receiving f ₁ and f ₂ using the antennas 4 and 5, and the code discriminating unit 92 detects a code from the output of the receiver 90. Further, the door level discriminating circuit 93 discriminates whether the output of the receiving unit 90 is a predetermined value (called a door level) or more, and the trunk level discriminating circuit 94 outputs the output of the receiving unit 91 is a predetermined value (called a trunk level) or more. Is determined. Reference numeral 95 is a circuit that prioritizes the trunk level from the outputs of both discrimination circuits. That is, the output A of the discrimination circuit 93 when f ₁ is detected is 1 and the discrimination circuit when f ₂ is detected
If the output B of 94 is 1, then in the area 6 of FIG.
= 1 and B = 0, and in the area 7, A = 1 and B = 1. Therefore, the required control contents are as follows.

Reference numeral 96 is a door / trunk opening / closing control circuit that controls the actuator 98 or 99 by referring to the output of the priority circuit 95 and the door opening / closing detection circuit 97 when the output C of the code discrimination unit 92 is 1 (match). In this case, since the trunk lock is always controlled only to open, a drive signal for opening may be sent to the actuator 99 every time, but in the case of a door lock, it is closed if it is open and open if closed. Since it is necessary to invert, the actuator 98 is driven according to the output of the detection circuit 97.

〔The invention's effect〕

As described above, according to the present invention, in order to distinguish the control contents according to the position of the transmitter, the transmitter may be one button, and
There is an advantage that an accurate judgment area can be obtained by using frequencies having different propagation characteristics such as 500 KHz and 60 MHz.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention, and FIG. 2 is a configuration showing an embodiment of the present invention. In the figure, 1 is a vehicle body, 2 is a door, 3 is a trunk, 4 and 5 are receiving antennas, 6 is a door control area, 7 is a trunk control area,
8 is a transmitter, 9 is a receiver, 81 is a transmission switch, 82 and 83 are transmission circuits, 90 and 91 are reception sections, 93 is a door level discrimination circuit, and 9
4 is a trunk level discrimination circuit, 96 is a door / trunk opening / closing control circuit, and 98 and 99 are actuators.

Claims (1)

[Claims] 1. A keyless entry device for transmitting or receiving radio waves from a transmitter outside a vehicle to a receiver on the vehicle side to open or close a lock of a door or a trunk of the vehicle, wherein a single switch is provided from the transmitter. When the radio waves of high and low two frequencies are transmitted at the same time during operation, the receiver locks the trunk lock when both radio waves are received at a predetermined level or more, and the door is opened when only high frequency radio waves are received at a predetermined level or more. A keyless entry device characterized by being configured to control opening and closing of a lock.