JPH08244525A - Speed reduction display device for vehicle - Google Patents

Abstract

PURPOSE: To prevent the occurrence of accidents, by displaying even an reduction in speed made by any operation other than normal footing operations similarly as an reduction in speed made by the normal footing operations, and accurately display an reduction in speed even when an vehicle is running over an inclined road, or the vehicle itself is inclined, or even when the vehicle is oscillated such as swinging and the like. CONSTITUTION: The output pulse of a wheel speed corresponding pulse output circuit 1 within an unit time is alternately counted by two count circuits 3 and 4, the difference between the resultant values of these counts is determined by subtraction 5 and 6, the resultant value after the subtraction is compared 8 and 9 with a display reference value set in advance by a display reference value setting circuit 7, and when comparison is shown as the resultant value after the reduction > (or >=) the display reference value, a display signal is outputted, and a display lamp 12 is thereby lighted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle deceleration display device for displaying a warning on a succeeding vehicle when the vehicle decelerates.

[0002]

2. Description of the Related Art In a conventional device of this type, as shown in FIG. 4, a switch 13 interlocked with the operation of a main braking device (foot brake) (not shown) is inserted between a power source E and braking lights 14, 14. , The brake lights 14,1 when the foot brake is activated
4 is turned on to display the following vehicle.

In such a conventional device, when the vehicle is decelerated by deceleration other than the operation of the foot brake, for example, engine braking, the brake lights 14 and 14 are not turned on.
Therefore, the following vehicle cannot immediately determine the deceleration of the preceding vehicle, and the deceleration of the preceding vehicle cannot be known until the distance between the following vehicle and the preceding vehicle decreases. Therefore, there is a risk of causing a delay in the brake operation of the following vehicle and causing an accident such as a rear-end collision.

Therefore, a device has appeared in which the deceleration display to the following vehicle is not dependent on the operation of the foot brake but the deceleration is directly detected and displayed. As shown in FIG. 5, this is provided with an acceleration sensor 15, an amplifier circuit 16, a comparison circuit 17, a display reference setting circuit 18, a control circuit 19 and indicator lights 20 and 20. That is, the acceleration sensor 15 is used to detect deceleration, and when the acceleration (negative acceleration: deceleration) detected by the acceleration sensor exceeds the set value of the display reference setting circuit 18, the indicator lights 20 and 20 are turned on. Then, it is displayed on the following vehicle.

However, in such a conventional apparatus, due to the characteristics of the acceleration sensor 15 used, when there is a road surface inclination or a vehicle inclination, for example, when traveling on a slope, the gravitational acceleration (g sin θ).
Therefore, the 0G level fluctuates (shifts). Therefore, with the acceleration sensor 15 alone, an accurate deceleration of the vehicle could not be obtained under conditions other than road inclination = 0 ° or vehicle inclination = 0 °. In addition, accurate deceleration cannot be obtained even when vibration such as swaying occurs in the vehicle.

[0006]

As described above, in the prior art, it is not possible to display deceleration other than the operation of the foot brake, for example, engine deceleration, and there is a risk of causing an accident such as a rear-end collision. , Road slope,
There is a problem in that accurate deceleration of the vehicle cannot be obtained under conditions other than vehicle inclination = 0 ° or when vibration such as swaying occurs in the vehicle.

An object of the present invention is to display deceleration other than the operation of the foot brake in the same manner as the deceleration by the foot brake, prevent accidents such as rear-end collisions, and prevent the occurrence of an acceleration sensor. PROBLEM TO BE SOLVED: To provide a deceleration display device for a vehicle, which is not affected by a large gravitational acceleration and can accurately detect and display deceleration even if there is road inclination, vehicle inclination, or vibration such as shaking of the vehicle. It is in.

[0008]

The above object is to provide a wheel speed corresponding pulse output circuit which outputs a pulse signal having a cycle corresponding to the rotation speed of a wheel of a vehicle, and a constant output pulse from the wheel speed corresponding pulse output circuit. A first pulse count circuit that counts every time and latches the value, and a second pulse count that counts and latches output pulses from the wheel speed corresponding pulse output circuit at timings that are alternate with the first pulse count circuit. Circuit and first and second subtracting output values of these first and second pulse counting circuits alternately
A subtraction circuit, a display reference setting circuit that sets a subtraction result value when performing deceleration display, and a set value of the display reference setting circuit and an output value of the first subtraction circuit are compared to determine whether deceleration display is necessary. A first comparing circuit for judging, a second comparing circuit for judging the necessity of deceleration display by comparing the set value of the display reference setting circuit and the output value of the second subtracting circuit, and these first, second
This is achieved by providing a control circuit for turning on and off the indicator lamp according to the result of the necessity judgment of deceleration display by the comparison circuit.

[0009]

The wheel-speed-corresponding pulse output circuit outputs a pulse signal having a cycle corresponding to the rotation speed of the wheels of the vehicle without depending on the operation of the foot brake, and enables subsequent digital processing. The first pulse counting circuit counts the output pulses from the wheel speed corresponding pulse output circuit at regular time intervals and latches the value, and the second pulse counting circuit similarly operates at a timing different from that of the first pulse counting circuit. The output pulse from the wheel speed corresponding pulse output circuit is counted and latched.

The first and second subtraction circuits alternately subtract the output values of the first and second pulse count circuits. The first comparison circuit compares the set value of the display reference setting circuit that sets the subtraction result value when performing deceleration display with the output value of the first subtraction circuit, determines whether deceleration display is necessary, and The comparison circuit is
The set value and the output value of the first subtraction circuit are compared to determine whether deceleration display is necessary.

The control circuit turns on and off the indicator lamp according to the result of the necessity judgment of deceleration display by the first and second comparison circuits.
That is, when the deceleration becomes constant or exceeds the constant deceleration, the indicator light is turned on and the deceleration is displayed on the following vehicle.

As a result, even if the deceleration is not due to the operation of the foot brake, the deceleration is displayed in the same manner as the deceleration due to the foot brake, and an accident such as a rear-end collision can be prevented. Further, since it is not affected by gravitational acceleration unlike an acceleration sensor, deceleration is accurately detected and displayed even if there is road inclination, vehicle inclination, or vibration such as swaying in the vehicle. It will be.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a vehicle deceleration display device according to the present invention. In FIG. 1, reference numeral 1 denotes a wheel speed-corresponding pulse output circuit for outputting a pulse signal having a cycle corresponding to the rotational speed of a wheel of a vehicle (not shown), and is composed of a wheel speed sensor 1a and a waveform shaping circuit 1b here.

In this case, the wheel speed sensor 1a is, for example,
Although not shown, an electromagnetic pickup having a built-in magnet and a gear that rotates integrally with the wheel are provided, and the sensor is configured to output an induced electromotive force (sine wave) having a cycle corresponding to the pitch of the gear according to the rotation of the wheel. In addition, the waveform shaping circuit 1b
Half-wave rectifies the sine wave output from the wheel speed sensor 1a,
The signal is converted into a square wave pulse signal (digital signal). Although the sine wave output from the wheel speed sensor 1a also changes in amplitude depending on the rotation speed of the wheel, the waveform shaping circuit 1b ignores the change in the amplitude and obtains a square wave pulse signal according to only the rotation speed of the wheel.

Reference numerals 3 and 4 set the counting of the number of pulses (wheel speed signal) from the wheel speed corresponding pulse output circuit 1 (waveform shaping circuit 1b) and the latching operation of the count value by a reference oscillation circuit described later. A first pulse count circuit and a second pulse count circuit that repeat at each operation timing.

Reference numeral 5 is a first subtraction circuit, which is used as a reference for the subtraction operation (AB) of the output signals (pulse count values latched respectively) A and B of the first and second pulse count circuits 3 and 4. Repeated at the operation timing set by the oscillator circuit,
The result value is output.

Reference numeral 6 is a second subtraction circuit, which subtracts the output signals A and B of the first and second pulse counting circuits 3 and 4 (B-
(A) is repeatedly output at the operation timing set by the reference oscillation circuit described later.

Reference numeral 7 is a display reference setting circuit, which includes the first and second display circuits.
A value obtained by subtraction of the subtraction circuits 5 and 6 (change in the number of pulses), that is, a display reference value indicating how much the wheel speed should be decelerated at a certain time before display is given to the following first and second comparison circuits. Is.

Reference numeral 8 denotes a first comparison circuit, which compares the signal from the first subtraction circuit 5 (subtraction result value = AB) with the signal from the display reference setting circuit 7 (display reference value) and subtracts it. When the result value AB exceeds the display reference value, it is determined that the display is necessary and the display signal is output.

Reference numeral 9 denotes a second comparison circuit, which compares the signal from the second subtraction circuit 6 (subtraction result value = BA) with the signal from the display reference setting circuit 7 (display reference value) and subtracts it. When the result value B-A exceeds the display result value, it is determined that the display is necessary, and the display signal is output.

Numeral 10 is for turning on / off the indicator lamp, which turns on the indicator lamp 12 when a display signal is input from the first comparison circuit 8 or the second comparison circuit 9 and turns it off in other cases. It is a control circuit. As the indicator light 12, this may be used also as a brake light, or may be provided separately from the brake light. Reference numeral 11 is a reference oscillating circuit for setting the reference time of the pulse count and controlling the operation timing of each of the circuits 3 to 6, 8 and 9.

Next, the operation of the device of the present invention will be described. The above-described device of the present invention basically has two counting circuits each of which is a pulse signal pulse output from the wheel speed corresponding pulse output circuit 1 within a unit time as a reference and having a cycle corresponding to the rotation speed of the wheel of the vehicle. The numbers 3 and 4 are alternately counted, and subtraction is performed between the count result values. Comparing the subtraction result value with the display reference value set by the display reference setting circuit 7, outputting a display signal when the subtraction result value> (or ≧) display reference value, and turning on the indicator lamp 12 Is.

The operation of each component will be described below in order. First, the wheel speed sensor 1a outputs a sine wave signal (AC signal) having a cycle corresponding to the wheel speed. Although this output signal also changes in amplitude, the apparatus of the present invention does not require a change in amplitude, and since it is basically digitally processed thereafter, this signal is half-wave rectified by the waveform shaping circuit 1b. Also, it is converted into a square wave pulse signal (digital signal) by the built-in comparator.

FIG. 2 is a waveform diagram showing this state. FIG. 2A shows the output signal of the wheel speed sensor 1a, that is, the waveform shaping circuit 1.
The input signal of b, (b) is a half-wave rectified signal in the waveform shaping circuit 1b, and (c) is an output signal of the waveform shaping circuit 1b, that is, a square wave pulse signal (digital signal).

Next, the reference oscillating circuit 11 controls the setting of the reference time of the pulse count and the operation timing of each of the circuits 3 to 6, 8 and 9. Hereinafter, the operation timing will be described with reference to FIGS. ) Is also used for the explanation.

First, the operation timing waveform A of one pulse count circuit, for example, the first pulse count circuit 3, is a waveform in which the pulse count and the latch of the count value are alternately repeated, and the latch time is longer than the count time. It is set a little longer. The operation timing waveform B of the other pulse counting circuit, for example, the second pulse counting circuit 4, has the same waveform as the operation timing waveform A, but is out of phase with the operation timing waveform A by 1/2 cycle. That is, as can be seen from FIG. 3, when one of the pulse count circuits 3 or 4 is in the counting state, the other pulse count circuit 4 or 3 is in the latching state, and as shown by the hatched line, When the pulse count circuit 3 or 4 enters the latch state from the count state, the other pulse count circuit 4 or 3 shifts from the latch state to the count state a predetermined time before (the latch of both pulse count circuits 3 and 4). The operation timing is set so that the states overlap for a predetermined time.

As a result, the first pulse counting circuit 3
Repeats counting and latching of pulses from the waveform shaping circuit 1b at the timing shown in FIG.
The second pulse counting circuit 4 repeats counting and latching the pulses from the waveform shaping circuit 1b at the timing shown in FIG. 3 (B).

Then, in the hatched portions (overlapping portions in the latched state) in FIGS. 3A and 3B, that is, between the counting operations of the first and second pulse counting circuits 3 and 4, subtraction and Perform comparison operation. First, in the shaded area a, the first subtraction circuit 5 operates and the output value A1 of the first pulse counting circuit 3
And the output value B1 of the second pulse count circuit 4 is subtracted, that is, A1-B1 is subtracted, and the resulting value is input to the first comparison circuit 8. The first comparison circuit 8 subtracts the subtraction result value (A1
-B1) is compared with the display reference value set by the display reference setting circuit 7, and a display signal is output when the subtraction result value> (or ≧) display reference value.

Next, in the shaded area b, the second subtraction circuit 6 operates to subtract the output value B1 of the second pulse counting circuit 4 from the output value A2 of the first pulse counting circuit 3, that is, B1-.
A2 is subtracted, and the resulting value is input to the second comparison circuit 9. The second comparison circuit 9 compares the subtraction result value (B1-A2) with the display reference value, and outputs a display signal when the subtraction result value> (or ≧) display reference value.

In the shaded portion c, as in the shaded portion a, the first subtraction circuit 5 operates and subtracts the output value A2 of the first pulse counting circuit 3 from the output value B2 of the second pulse counting circuit 4, that is, A2. -Subtract B2. After that, the shaded area a
The operation is similar to.

In this way, a series of operations of pulse counting → count value latching → subtraction → comparison are repeated. Then, when the display signal is output from the first comparison circuit 8 or the second comparison circuit 9, the control circuit 10 operates to turn on the indicator lamp 12. The above operation is performed during deceleration, that is, when the subtracted value> the subtracted value, and the subtraction result value at that time is output from the subtraction circuit 5 or 6 to detect the change in the wheel speed.

On the other hand, at the time of constant speed and acceleration, it operates as follows. First, at constant velocity, the subtracted value = the subtracted value, so
Since the subtraction result value is 0, the display signals are not output from the comparison circuits 8 and 9, and the indicator lamp 12 does not light.

During acceleration, the subtracted value is smaller than the subtracted value, so that the subtraction result value is output as a negative value as it is. However, the vehicle deceleration display device detects only when decelerating,
Since the display is necessary, the subtraction circuits 5 and 6 are provided with the following processing functions to cope with this. That is, the subtraction circuits 5 and 6 are configured to take the logical product (AND) of the carry-out signal and the output signal (subtraction result value), whereby the subtraction result value during acceleration is the same as during constant velocity. It becomes 0, no display signal is output from the comparison circuits 8 and 9, and the indicator lamp 12 does not light.

The above-described operation is repeated while the vehicle is running,
At the time of deceleration exceeding the display reference value, a display signal is given to the control circuit 10 to turn on the indicator lamp 12 to inform the following vehicle that the vehicle is in the decelerated state.

[0035]

As described above, according to the present invention, even when deceleration other than the operation of the foot brake, for example, the engine deceleration or the like, the indicator light (for example, a brake light) is turned on when the deceleration exceeds a preset value. Since this is done, the occurrence of an accident such as a rear-end collision can be prevented in advance, and there is an effect that the safety is improved.

Further, since the deceleration is detected from the change of the wheel speed (= the change of the vehicle speed), it is not affected by the gravitational acceleration unlike the acceleration sensor, and even if there is a road inclination or a vehicle inclination, Alternatively, there is an effect that the deceleration can be accurately detected and displayed even if vibration such as swaying occurs in the vehicle.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a device of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the waveform shaping circuit in FIG.

FIG. 3 is a time chart for explaining the operation of the device of the present invention shown in FIG.

FIG. 4 is a block diagram of a conventional device.

FIG. 5 is a block diagram of a conventional device different from FIG.

[Explanation of symbols]

1 ... Wheel output pulse output circuit, 1a ... Wheel speed sensor,
1b ... Waveform shaping circuit, 3, 4 ... First and second pulse count circuits, 5, 6 ... First and second subtraction circuit, 7 ... Display reference setting circuit, 8, 9 ... First and second comparison circuit, 10 ... Control circuit for turning on / off indicator light, 11 ... Reference oscillation circuit, 12, 2
0 ... Indicator light, 13 ... Switch, E ... Power supply, 14 ... Braking light, 15 ... Acceleration sensor, 16 ... Amplification circuit, 17 ... Comparison circuit, 18 ... Display reference setting circuit, 19 ... Control circuit.

Claims (1)

[Claims] 1. A wheel speed corresponding pulse output circuit for outputting a pulse signal having a cycle corresponding to the rotation speed of a wheel of a vehicle, and an output pulse from this wheel speed corresponding pulse output circuit is counted at a constant time interval and the value is counted. A first pulse counting circuit for latching, a second pulse counting circuit for counting and latching output pulses from the wheel speed corresponding pulse output circuit at timings alternating with the first pulse counting circuit, and these first and first pulse counting circuits. First and second subtraction circuits that alternately subtract the output value of the two-pulse count circuit, a display reference setting circuit that sets a subtraction result value when performing deceleration display, a set value of this display reference setting circuit, and the first Comparing the output value of the 1 subtraction circuit to determine the necessity of deceleration display, the set value of the display reference setting circuit and the output value of the second subtraction circuit, It is characterized by comprising a second comparison circuit for judging whether or not the deceleration display is necessary, and a control circuit for turning on / off the indicator lamp in accordance with a result of judgment as to whether or not the deceleration display is necessary by these first and second comparison circuits. Vehicle deceleration display device.