JPS61186885A - Ultrasonic sensor for vehicle - Google Patents

Abstract

PURPOSE:To detect a precipice and a ditch behind a vehicle when it backs and to obtain safety in dead angle by providing a switching means which alternates freely the 1st detection state in which a road surface is detected and the 2nd detection state in which the road surface is not detected. CONSTITUTION:A receiving circuit 2, a pulse internal determining circuit 3, a monostable multivibrator (MM) 4, an oscillation circuit 5, amplifying circuits 6 and 8, a tuning amplifying circuit 9, a detecting circuit 11, a detecting circuit 12, an AND gate 13, a gate circuit 14, a display circuit 15, etc., are provided. Then, the circuit 3 drives the MM 4 and the circuit 5 is driven with its output to generate a frequency at which a transmitter receiver 7 is driven. This frequency is amplified by the circuit 6 and sent to the transmitter receiver 7, thereby sending an ultrasonic wave to a detection body. Further, when a reflected wave returns, a fine-level signal is amplified by the circuit 8 of the circuit 2 and further selected by the circuit 9. Then, the signal from the circuit 9 is detected by the circuit 11 and the circuit 12 operates when the signal is higher than an operation level. Further, when its output exceeds the operation level, a signal is sent to the gate 13 and ANDed with the signal from the circuit 14 and the circuit 15 operates to make a display etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field 1] The present invention relates to an ultrasonic sensor for a vehicle that is attached to the rear or front part of an automobile, or the front part of an oak car.

[Background Art] A conventional back sensor for a vehicle detects waves transmitted from the back sensor and reflected from obstacles, and determines whether or not there is an obstacle within a certain distance in the direction of the vehicle. Fortunately, if there is a cliff or ditch behind the vehicle, it cannot be detected and is dangerous.

[Objective of the Invention 1] The present invention has been provided in view of the above-mentioned points, and is a super vehicle for vehicles that detects cliffs and grooves behind the vehicle that cannot be detected by current vehicle back sensors when backing up, and has blind spot safety. The purpose is to provide a sound wave sensor.

[Disclosure of the invention 1 (Example 1) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a block diagram of the ultrasonic sensor A, which is composed of a wave transmitting circuit 1, a wave transmitter/receiver 7, and a wave receiving circuit 2. The wave transmitting circuit 1 includes a pulse interval determining circuit 3 that determines the interval of the ultrasonic waves to be transmitted, a monostable multivibrator 4 that is driven by the pulse interval determining circuit 3 and determines the width of the transmitted ultrasonic wave signal, and a monostable multivibrator 4 that determines the width of the transmitted ultrasound signal. It is composed of an oscillation circuit 5 driven by a multivibrator 4 and an amplifier circuit 6 that amplifies the output of the oscillation circuit 5. The transducer 7 is composed of, for example, a microphone, and serves both to transmit ultrasonic waves and to receive reflected waves. The wave receiving circuit 2 also includes an amplifier circuit 8 that amplifies the reflected wave from the transducer 7, a tuned amplifier circuit 9 that selectively amplifies the output signal of the amplifier circuit 8, and a detection circuit that detects the output of the tuned amplifier circuit 9. 11, and a level detection circuit 12 that detects whether the output of the detection circuit 11 is equal to or higher than the operating level.
, WIJ! by AND date 13 between the level detection circuit 12 output and the date circuit 14 output. ! A display circuit 15 that provides notification or display based on the multiplied output, a switch circuit 10 that varies the amplification factor of the tuned amplifier circuit 9, and a display reversal instruction circuit 1.
It consists of 6 mag.

Next, the general operation of the ultrasonic sensor A will be explained. Now, when the ultrasonic sensor A is powered on, the monostable multivibrator 4 is driven by the pulse interval determining circuit 3, and the oscillation circuit 5 is driven by the output of this monostable multipipe rake 4.

This oscillation circuit 5 generates a frequency that drives a transducer 7, and the frequency from this oscillation circuit 5 is amplified by an amplifier circuit 6 and sent to the transducer 7, and from the transducer 10 toward the sensing object. Ultrasonic waves are transmitted.

When the reflected wave bounces back, the weak signal passed through the transducer 7 is amplified by the amplifier circuit 8 of the receiver circuit 2 and further selected by the tuned amplifier circuit 9. The signal from the tuned amplifier circuit 9 is detected by the detection circuit 11, and if the signal is above the operating level, the level detection circuit 12 is activated. That is, so-called operation level detection is performed by this level detection circuit 12. If the detection output exceeds the operating level, the signal is sent to the AND date 13, and in the seventh AND date 13, AND is performed with the date signal from the date circuit 14, and the display circuit 15 is activated to display or notify. Do the following.

By the way, the ultrasonic sensor A is installed at the rear of the vehicle B, and the state shown in FIG. It works as a sensor and detects human obstacles. The range indicated by the solid line in the figure indicates the detection area by the ultrasonic sensor A. Figure 1(b) shows the switch circuit 1
The switch SW 0 is turned on, and the detection area is expanded so that it can detect the road surface. Note that the size of the detection area is not absolute, and the size of the detection area is
By turning on Wl, the amplification factor of the tuned amplifier circuit 9 is increased,
This increase in the amplification factor of the tuned amplification circuit 9 increases the reflected components of the ultrasonic waves, thereby expanding the detection area. That is, the switching means is constructed by varying the amplification factor of the tuned amplifier circuit 9 by operating the switch SW.

Further, the amplification factor of the tuned amplifier circuit 9 can be increased by using the switch S.
By turning on W, the attenuation resistance of the amplifier can be short-circuited using a transistor or the like. Figure 1(b)
When the ultrasonic waves are no longer reflected on the road surface, a cliff, groove, etc. exists behind that position, and the presence of the cliff, groove, etc. is displayed on the display circuit 15. Also, at this time, the distance display between the road surface and vehicle B is always displayed at point P where the detection area touches the road surface, that is, distance X, and when the distance between the vehicle and the cliff becomes smaller due to the display of distance X, This will alert you to the presence of a cliff without any detectable object. At this time, the display reversal instruction circuit 16 causes
It can also display to the driver when the road surface is no longer reflective. The switch SW of the switch circuit 10 is provided on the driver's seat side of the vehicle B, and the amplification factor of the tuned amplifier circuit 9 is changed by turning on and off the switch SW, so that the road surface can be easily detected. I have to.

Further, in the above embodiment, the amplification factor of the wave receiving circuit 2 is increased, but it is also possible to increase the amplification factor of the amplification circuit 6 of the wave transmitting circuit 1 to widen the detection area and detect the road surface. good.

(Embodiment 2) FIGS. 3 to 5 show another embodiment in which the angle of the transducer 7 of the ultrasonic sensor A is changed.

That is, the presence or absence of a road surface is detected by changing the angle of the horn 17 of the transducer 7. Figure #&4 shows a configuration diagram of the switching means, and Figure @5 shows a block diagram. The timer 20 is activated by the switch SW2 of the switch circuit 10'.
The motor 19 is rotated forward and backward through the motor 19.
An ultrasonic sensor A is attached to the horn 17 via a gear box 18 to change the vertical angle of the horn 17. The horn 17 is turned upward to detect obstacles such as people, and the horn 17 is turned downward to detect road surfaces.

Note that the other circuits shown in FIG. 5 are the same as those in the above embodiment, and therefore their explanations will be omitted.

[Effects of the Invention 1 As described above, the present invention includes a wave transmitting circuit that transmits ultrasonic waves from a transducer and a receiving circuit that receives reflected waves from the ultrasonic waves via the transducer. This ultrasonic sensor is provided with a switching means that can freely switch between a first detection state in which the road surface is detected and a second detection state in which the road surface is not detected. The fj&1 detection state that detects the road surface as necessary has the effect of improving vehicle safety by detecting cliffs, grooves, and the like.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) show examples of the present invention! FIG. 2 is a block diagram of the same as above, FIG. 3 is an explanatory diagram of another embodiment, FIG. 4 is a block diagram of the switching means same as above, and FIG. 5 is a block diagram of same as above. 1 is a wave transmitting circuit, 2 is a wave receiving circuit, 6 is an amplifier circuit, 7 is a transducer, 8 is an amplifier circuit, and 17 is a horn. Agent Patent Attorney Ishi 1) Ai 7 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (3)

[Claims] (1) A road surface is detected in an ultrasonic sensor equipped with a wave transmitting circuit that transmits ultrasonic waves from a transducer and a receiving circuit that receives reflected waves from the ultrasonic waves via the transducer. An ultrasonic sensor for a vehicle, comprising a switching means that allows switching between a first detection state and a second detection state in which no road surface is detected. (2) The ultrasonic sensor for a vehicle according to claim 1, wherein the switching means is configured to freely vary the amplification factor of the amplifying circuit of the wave transmitting circuit or the amplifying circuit of the wave receiving circuit. (3) The ultrasonic sensor for a vehicle according to claim 1, wherein the switching means is configured to freely change the angle of a horn for transmitting ultrasonic waves from the transducer.