JPH0458576B2 - - 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 was a problem that the cost was high.

(Objective of the Invention) The object of the present invention is to detect a slip condition based on a comparison of the rate of change in the rotational speed, that is, the acceleration, instead of detecting the slip condition based on the difference in rotational speed between the driving wheel and the idler wheel as in the conventional method. By doing so, it is possible to easily and accurately detect a slip state, and it is an object of the present invention to provide an automobile wheel slip detection device which is inexpensive in cost and excellent in practicality.

(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 a driving wheel; and an arithmetic means for calculating the rate of change in the rotational speed detected by the rotational speed detection means. , an acceleration detection means for detecting the acceleration of the vehicle body, a comparison means for calculating the difference between the signals of the calculation means and the acceleration detection means, and a comparison means for detecting that the value obtained by the comparison means is greater than or equal to a set value. and a determination means that emits a signal indicating the slip state of the wheels, thereby determining the apparent acceleration of the vehicle body due to the rate of change in the rotational speed of the driving wheels and the vehicle body detected by the acceleration detection means. The slip condition of the wheel is detected based on comparison with the true acceleration.

(Effects of the Invention) Therefore, according to the present invention, the acceleration of the wheels is determined based on the comparison between the apparent acceleration of the vehicle body due to the rate of change in the rotational speed of the driving wheels and the true acceleration of the vehicle body detected by the acceleration detection means. By detecting the slip condition, it is not necessary to accurately detect the absolute value of the rotational speed of the drive wheels, etc., as in the past, and it is sufficient to detect the rate of change. Moreover, since the rate of change itself does not differ between the left and right wheels even during a large steering turn, slip detection can be performed accurately by using only one rotational speed detection means with normal accuracy. Therefore, it is possible to provide an automobile wheel slip detection device that is inexpensive and has excellent practicality.

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

FIG. 1 shows a schematic configuration of an FR (front engine, rear drive) type automobile equipped with a wheel slip detection device according to a first embodiment of the present invention, where 1 is a vehicle body, and 2 is a vehicle disposed at the front of the vehicle body 1. engine, 3
is a transmission disposed at the rear of the engine 1, and the transmission 3 transmits power to rear wheels (drive wheels) 7, 7 via a propulsion shaft 4, a differential 5, and a rear wheel 6. Possibly connected.

Further, reference numeral 8 denotes rotational speed detection means for detecting the rotational speed of the drive shafts 7, 7 by detecting the rotational speed of the propulsion shaft 4;
Reference numeral 9 denotes an acceleration detection means provided in the vehicle body 1 to detect the acceleration of the vehicle body 1 based on the principle of a pendulum, and each of the detection means 8 and 9 sends and receives a signal to an electronic determination circuit 10 for determining a slip. Possibly connected. The electronic determination circuit 10 is a differentiation circuit that receives a signal from the rotational speed detection means 8 via a frequency-voltage converter 11 and a filter 12, differentiates the rotational speed of the driving wheels 7, 7, and calculates the rate of change gn. The signal from the calculation means 13 and the signal from the acceleration detection means 9 are transmitted to an amplifier 14.
The difference between the rate of change gn of the rotational speed of the drive wheels 7, 7 and the acceleration gs of the vehicle body
Comparison means 1 consisting of a subtracter that calculates gn−gs|
5 and the above difference from the comparison means 15 |gn-gs|
The signal according to Judgment means 17 consisting of a comparator that emits an "H" signal indicating the slip state of the
It is equipped with As described above, the slip state of the wheels is detected based on the comparison between the apparent acceleration of the vehicle body 1 due to the rate of change in the rotational speed of the driving wheels 7, 7 and the true acceleration of the vehicle body 1 detected by the acceleration detection means 9. The wheel slip detection device A of the present invention is configured as follows.

Incidentally, when a wheel slip condition is detected by the wheel slip detection device A (electronic judgment circuit 1
0 determination means 17), as a countermeasure against the slip, the detection signal "H" signal may be 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 above embodiment,
When driving normally 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, and the rate of change in the rotational speed of the driving wheels 7, 7 changes. A proportional relationship is maintained with the acceleration of the vehicle body 1.

At this time, in the wheel slip detection device A of the present invention, the determination means 17 of the electronic determination circuit 10 determines the difference |gn-gs| Since it is determined that the value is smaller than the set value go of the reference value setter 16, the determining means 17 does not issue an "H" signal indicating the wheel slip state.

On the other hand, when driving suddenly 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 and the acceleration of the vehicle body 1 is reduced by the driving wheels 7. , 7 no longer follows the rate of change in the rotational speed of the two, and as a result, the proportional relationship between them collapses and a large difference occurs between them. In addition, Figure 3 shows the change characteristics of the apparent speed and true speed of the vehicle body determined from the rotational speed detection of the driving wheels and idler wheels during a sudden start on a road with a low coefficient of frictional resistance. FIG. 4 similarly shows the change characteristics of the apparent acceleration and true acceleration of the vehicle body. These two figures show that immediately after starting, the true speed of the vehicle is much smaller than the apparent speed due to the slip of the drive wheels, and the proportional relationship between the apparent acceleration of the vehicle and the true acceleration is perfect. It turns out that it collapses.

At this time, in the wheel slip detection device A,
The determination means 17 of the electronic determination circuit 10 determines whether the driving wheels 7, 7
It is detected that the difference between the rate of change gn of the rotational speed of the vehicle body 1 and the acceleration gs of the vehicle body 1 is greater than the set value go, and the determination means 17 outputs an "H" signal indicating the slip state of the wheel. It will be issued.

In this way, the wheel slip detection device A of the present invention
The slip detection is performed using the difference between the rate of change gn of the rotational speed of the drive wheels 7 and the acceleration gs of the vehicle body |gn−gs
Since it is based on whether | is equal to or greater than a set value go, the rotational speed detection means 8 for detecting the rotational speed of the drive wheels 7, 7 uses the conventional difference in rotational speed between the drive wheels and the idle wheels. It is not necessary to use a high-precision device that can accurately detect the absolute value of the rotational speed, as is the case when determining whether or not the absolute value of the rotational speed is greater than or equal to a set value. can be used. Moreover, this means that the acceleration detection means 9 for detecting the acceleration of the vehicle body 1
The same applies to

Further, since the rotational speed detection means 8 and the acceleration detection means 9 are not affected by steering depending on their set positions, even one each can sufficiently perform its detection function. As a result, as mentioned above, it is not necessary to use high-precision detection means 8 and 9, and together with this, it is possible to significantly reduce costs, which is very advantageous in terms of implementation.

FIG. 2 shows a slip determination flow in a microcomputer in a second embodiment of the present invention in which a microcomputer is used in place of the electronic determination circuit 10 in the first embodiment. be. To explain this flow, first, in step S _A , it is determined whether or not it is the measurement timing for each predetermined time, and after waiting for the measurement timing, in step S _B , based on the signal from the rotational speed detection means 8, the drive wheels 7, The rate of change gn is calculated from the difference between the current rotation speed of 7 and the previous rotation speed, and the acceleration of the vehicle body 1 is calculated based on the signal of the acceleration detection means 9 in step S _C.
Read gs. Then, in step S _D , the rate of change gn of the rotational speed of the drive wheels 7, 7 and the acceleration of the vehicle body are
After calculating the difference between gs and |gn−gs|, step
At S _E , compare the above difference |gn-gs| with the set value go corresponding to the slip state of the drive wheels 7, 7,
If NO is less than the set value go, the step judgment flag is set to ``0'' in step S <sub>F</sub> , while if YES is greater than the set value go, the slip judgment flag is set to ``1'' in step S _G and the process returns to the start. Thereafter, repeat the above operation.

It should be noted that the present invention is not limited to the above embodiments, but includes various other modifications. For example, in the above 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. (in the case of the above embodiment, the rotational acceleration of the front wheel) is detected,
The acceleration of the vehicle body 1 may be detected based on the rotational acceleration. In this case, since the rotational acceleration of the idle wheels does not differ between the left and right wheels even during a large turning, only one acceleration detection means is required, and the same cost reduction effect as in the above embodiment is achieved.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a schematic configuration diagram showing the first embodiment, and FIG. 2 is a flowchart showing the slip judgment flow in the microcomputer used in the second embodiment. It is. Figures 3 and 4 show the results of a sudden start test on a road with a low coefficient of friction and drag. Figure 3 shows the change characteristics of the apparent speed and true speed of the car body, and Figure 4 shows the change characteristics of the apparent speed and true speed of the vehicle body. is a diagram showing the change characteristics of the apparent acceleration and true acceleration of the vehicle body. A...Wheel slip detection device, 1...Vehicle body, 7
... Rear wheel (drive wheel), 8 ... Rotation speed detection means,
9... Acceleration detection means, 13... Calculation means, 15
... Comparison means, 17... Judgment means.

Claims (1)

[Claims] 1. A rotational speed detection means for detecting the rotational speed of the drive wheel, a calculation means for calculating the rate of change in the rotational speed detected by the rotational speed detection means, an acceleration detection means for detecting the acceleration of the vehicle body, and the above-mentioned calculation means. and an acceleration detecting means, and a determining means that detects that the value obtained by the comparing means is equal to or higher than a set value and issues a signal indicating the slip state of the wheel. An automobile wheel slip detection device characterized by: