JPH0458577B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a wheel slip detection device for detecting a state in which the drive wheels of an automobile are idling, that is, a slip state.

(Prior Art) Conventionally, as a wheel slip detection device of this type of automobile, as disclosed in, for example, Japanese Utility Model Application Publication No. 51-44046, the rotational speed of a driving wheel and an idler wheel is detected by a rotation detector, It is known that the slip state of the driving wheels is detected based on the difference between the two rotational speeds.

However, since the conventional wheel slip detection device described above detects the slip state based on the difference in rotation speed between the driving wheel and the idle wheel, it is difficult to accurately measure the absolute value of each rotation speed using a rotation detector. need to be detected. For this reason, it is necessary to use a rotation detector with high detection accuracy, and since the rotation speed of the left and right wheels differs significantly during large steering turns, rotation detectors must be installed for all four wheels. However, as a result, there were problems in that the cost was high, and there were also problems in terms of reliability.

(Object of the Invention) In view of the above, it is an object of the present invention to limit the slippage of the wheels (driving wheels) only when changing the vehicle speed (particularly when starting) and to reduce the rotational speed of the driving wheels when the wheels slip. Focusing on the fact that the vehicle speed itself does not change even if the speed changes, and there is a large difference between the two change points, we developed a system that detects this difference to easily and accurately detect the slip condition, reducing costs. The object of the present invention is to provide an automobile wheel slip detection device that is inexpensive, has high detection accuracy, and is highly practical.

(Structure of the Invention) In order to achieve the above object, the present invention includes a rotational speed detection means for detecting the rotational speed of the drive wheels, an acceleration detection means for detecting the acceleration of the vehicle body, and an output signal from both of the above detection means. and determining means that determines that the time difference between the rotational speed change of the drive wheels and the acceleration/deceleration of the vehicle body is greater than a set value, and issues a signal indicating the slip state of the wheels. . As a result, if the drive wheels slip when changing the vehicle speed, a time difference will occur between the time when the rotational speed of the drive wheels changes and the time when the vehicle body accelerates or decelerates, and based on the detection of this time difference, the slip state of the wheels will occur. It is designed to detect.

(Effects of the Invention) Therefore, according to the vehicle wheel slip detection device of the present invention, the slip state of the wheels is detected by detecting the time difference between the time when the rotational speed of the driving wheel changes and the time when the vehicle body accelerates or decelerates. As a result, it is not necessary to provide high-precision rotational speed detection means for all four wheels to accurately detect the absolute value of the rotational speed, as in the past, and the rotational speed detection means etc. need to be equipped with high-precision rotational speed detection means. Since slip detection can be reliably performed using just one device, it is possible to effectively reduce costs and improve detection accuracy.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 shows a wheel slip detection device A for detecting the slip state of the drive wheels of an FR (front engine, rear drive) type vehicle as a first embodiment of the present invention.
The overall configuration of this wheel slip detection device A is shown below.
This is to detect a slip condition especially when starting the vehicle, when the slip condition is likely to occur.

In FIG. 1, 1 is a vehicle body, 2 is an engine disposed at the front of the vehicle body 1, and 3 is a transmission disposed at the rear of the engine 1, and the transmission is connected to a propulsion shaft 4. , are connected to rear wheels (drive wheels) 7, 7 via a differential 5 and a rear axle 6 so as to be capable of transmitting power.

Further, reference numeral 8 denotes rotational speed detection means for detecting the rotational speed of the driving wheels 7, 7 by detecting the rotational speed of the propulsion shaft 4;
Reference numeral 9 denotes an acceleration detection means provided on the vehicle body 1 to detect the acceleration of the vehicle body 1 based on the principle of a pendulum. Reference numeral 10 determines whether or not a start is to be started based on the accelerator pedal force, gear position, etc., and issues a signal when the start is started. The detection means 8, 9 and the determination means 10, which serve as a start start determination means, are each connected to an electronic determination circuit 11, which serves as a determination means for determining a slip, so as to be able to send and receive signals.

The electronic determination circuit 11 includes the start start determination means 1
0 and the signal from the rotational speed detection means 8; a detection circuit 13 which receives the signal from the acceleration detection means 9 and detects the point in time when the vehicle body 1 starts moving; During the period from when the signal is received at the S terminal 14a until the signal from the detection circuit 13 is received at the R terminal 14b, that is, from the time when the drive wheels 7, 7 start rotating at the time of starting, the vehicle body 1
A flip-flop circuit 14 emits a signal from the Q terminal 14c, and an AND circuit receives a signal from the Q terminal 14c of the flip-flop circuit 14 and a signal emitted from the clock signal generator 15 at predetermined intervals until the start of movement of the flip-flop circuit 14. 16, a counter 17 that counts the number of signals emitted from the AND circuit 16, and receives the signal from the detection circuit 13 as a judgment command signal via the noise removal circuit 18, and calculates the number of counts in the counter 17, that is, the drive. A signal corresponding to the time difference ts between the rotation start point of the wheels 7, 7 and the movement start point of the vehicle body 1 is set to a pre-stored setting value t ₀ corresponding to the slip state of the drive wheels 7, 7.
and a comparison circuit 19 which compares the _magnitude of the difference between the drive wheels 7, 7 and the movement start point of the vehicle body 1. , the comparison circuit 19
The vehicle is configured to emit an "H" signal indicating the slip condition of the wheel.

Incidentally, when a wheel slip condition is detected by the wheel slip detection device A (electronic judgment circuit 1
When the "H" signal is emitted from the comparator circuit 19 of No. 1), as a countermeasure against the slip, the detection signal "H" signal is used to sound a warning buzzer to alert the driver, or to suppress the slip. This involves changing the support rigidity of the suspension, the output of the engine, etc.

Next, to explain the operation of the wheel slip detection device A, when transmitting on a general road where the coefficient of frictional resistance of the road surface is relatively high, the driving wheels 7, 7 roll on the road surface without slipping. , the time when the drive wheels 7, 7 start rotating and the time when the vehicle body 1 starts moving almost coincide.

At this time, in the wheel slip detection device A,
The comparison circuit 19 of the electronic judgment circuit 11 determines whether the driving wheels 7, 7
Since it is determined that the time difference t _S between the start of rotation and the start of movement of the vehicle body 1 is smaller than the set value t ₀ corresponding to the slip state of the drive wheels 7, the comparison circuit 19 determines the slip state of the wheels. No "H" signal is generated for display.

On the other hand, when starting on a road where the coefficient of frictional resistance of the road surface is reduced due to wetness, freezing, etc., the driving wheels 7, 7 slip on the road surface,
The vehicle body 1 does not immediately start moving when the drive wheels 7, 7 start rotating, and there is a large time difference between these two starting points. Figure 2 shows the change characteristics of the rotational speed of the driving wheels and the acceleration of the vehicle body when starting on a road with a _low coefficient of frictional resistance. It can be seen that a large time difference t _S of about 1 second occurs between the movement start point P 2 and the movement start point P ₂ .

At this time, in the wheel slip detection device A,
The comparison circuit 19 of the electronic judgment circuit 11 determines whether the driving wheels 7, 7
It is detected that the time difference t _S between the rotation start point of the vehicle body 1 and the movement start point of the vehicle body 1 is greater than or equal to the set value t0, and the comparison circuit ₁₉ issues an "H" signal indicating the wheel slip state. Become.

In this way, the wheel slip detection device A detects a slip at the time of starting based on the time difference between the time when the drive wheels 7, 7 start rotating and the time when the vehicle body 1 starts moving.
Since it is based on whether t _S is greater than or equal to the set value t ₀ , the rotation speed detection means 8 for detecting the rotation speed of the drive wheels 7 , 7 can be used to detect the rotation speeds of the conventional drive wheels and idle wheels. It is not necessary to use a highly accurate device that can accurately detect the absolute value of the rotation speed, as is the case when the difference between can be used. This also applies to the acceleration detection means 9 that detects the acceleration of the vehicle body 1 and the start start determination means 10 that determines the start of start.

Moreover, the detection means 8, 9 and the determination means 10
are not affected by steering depending on their installation position, so even one of each can fully perform its function, and as a result, as described above, the detection means 8, 9 and the determination means 10 Coupled with the fact that there is no need to use a highly accurate one, it is possible to significantly reduce costs.

Furthermore, as described above, the wheel slip detection device A detects slips using a simple configuration in which one each of the detection means 8, 9 and the determination means 10 are of normal accuracy. Detection accuracy can be improved without the risk of

The reason why the wheel slip detection device A of the above embodiment detects only the slip state of the driving wheels 7, 7 at the time of starting is because slips are likely to occur at the time of starting. It depends on the reason. In other words, when starting,
Even if measures are taken to suppress slips, because the vehicle speed is low, the behavior of the vehicle body 1 will not change significantly, and the driver will not feel psychologically pressured, so slip detection is not practical. It depends on what is specifically needed.

FIG. 3 shows a modification of the above embodiment in which the determination means for determining slip of the wheel slip detection device A is configured using a microcomputer in place of the electronic determination circuit 11 in the above embodiment. This figure shows the flow of slip determination using a microcomputer. To explain this flow, first, as a start, step S _A
In step S B, it is determined whether or not the start has started based on the signal from the start start determination means 10, and after waiting for the start of start, it is determined in step S _B whether or not the rotation of the driving wheels 7, 7 has started based on the signal from the rotational speed detection means 8. do. Then wait for the drive wheels 7, 7 to start rotating and step S _C
After starting time counting at step S _D
Based on the signal from the acceleration detection means 9, the vehicle body 1
After waiting for this start of movement, the time difference t _S between the time when the drive wheels 7, 7 start rotating and the time when the vehicle body 1 starts moving is read in step S _E. After that, in step S _F, the above time difference t _S
is the setting value corresponding to the slip condition of the drive wheels 7, 7.
Compare the size with t ₀ , and if NO, which is less than the set value t ₀ , set the slip judgment flag to "0" in step S _G.
On the other hand, if the set value _t0 or more is YES, the slip determination flag is set to "1" in step S _H and the process ends.

Further, FIG. 4 shows, as a second embodiment of the present invention,
This figure shows the overall configuration of a wheel slip detection device A' that detects the slip state of the driving wheels not only when starting as in the first embodiment but also generally when changing the vehicle speed. An electronic determination circuit 11' serving as determination means for determining slip in this wheel slip detection device A' receives a signal from the rotation speed detection means 8 and includes a first detection circuit 20 for detecting the time point at which the rotation speed of the drive wheel changes. , a second receiving the signal from the acceleration detecting means 9 and detecting the acceleration/deceleration point of the vehicle body.
In addition, a flip-flop circuit 1 is provided as in the case of the electronic determination circuit 11 in the wheel slip detection device A of the first embodiment.
4. It is equipped with an AND circuit 16, a counter 17, a comparison circuit 19, etc., and the comparison circuit 19 determines that the time difference _tS between the time of change in the rotational speed of the driving wheels and the time of acceleration/deceleration of the vehicle body is greater than or equal to the set value _t0 . When this occurs, the comparator circuit 19 is configured to issue an "H" signal indicating the wheel slip condition.

In the case of the wheel slip detecting device A', its operation is the same as that of the wheel slip detecting device A of the first embodiment, and the operation is the same as that of the wheel slip detecting device A of the first embodiment. Since the slip state of the drive wheels is detected based on the detection of the time difference between the two wheels, it is possible to reduce costs and improve detection accuracy.

It should be noted that the present invention is not limited to the above embodiments, but includes various other modifications. For example, in the first embodiment, a so-called G sensor based on the principle of a pendulum was used as the acceleration detection means 9 for detecting the acceleration of the vehicle body 1. Of course, the rotational acceleration of the idle wheel (the front wheel in the above embodiment) may be detected, and the acceleration of the vehicle body 1 may be detected based on the rotational acceleration.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. Fig. 1 is a schematic configuration diagram showing the first embodiment, and Fig. 2 shows the rotational speed of the drive wheels and the acceleration of the vehicle body when starting on a road with a low coefficient of frictional resistance. FIG. 3 is a flowchart showing the slip judgment flow in the microcomputer used in a modification of the first embodiment, and FIG. 4 is a schematic configuration diagram showing the second embodiment. It is. A, A'...wheel slip detection device, 1...vehicle body, 7...rear wheel (drive wheel), 8...rotational speed detection means, 9...acceleration detection means, 11, 11'...
Electronic judgment circuit.

Claims (1)

[Claims] 1 A rotational speed detection means for detecting the rotational speed of the drive wheels, an acceleration detection means for detecting the acceleration of the vehicle body, and receiving output signals from both of the above detection means, and detecting the point of change in the rotational speed of the drive wheels and acceleration/deceleration of the vehicle body. 1. A wheel slip detection device for an automobile, characterized in that the device comprises determining means for determining that the time difference from the current time is equal to or greater than a set value and emitting a signal indicating the slip state of the wheel.