JPH09292403A - Rotating speed detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a rotating speed detecting device, which is suitable as a device for detecting the rotating speed of the wheels of a vehicle, from incorrectly detecting the rotating speed by disturbances such as vibrations. SOLUTION: A wheel speed sensor 14 consists of a rotor with an irregular surface which rotates eccentrically with respect to a wheel 12 and an electromagnetic pickup sensor, arranged at a location facing the irregular surface. When the wheel is rotating, the signal with undulation caused by the eccentricity of the rotor which is superimposed on the waveforms, in the form of pulses caused by the irregular surface, is outputted from the electromagnetic pickup sensor. When undulation is not superimposed on the signal, the signal is judged as being not caused by the rotation of the wheel 12 but as being caused by disturbances such as vibrations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation speed detection device, and more particularly to a rotation speed detection device suitable as a device for detecting the rotation speed of a vehicle wheel.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-4-29225
As disclosed in No. 3, as a device for detecting the rotation speed of a wheel of an automobile, a device for outputting a pulse signal each time the wheel rotates by a predetermined rotation angle is known. The above-mentioned device can be configured by a rotor having an uneven outer peripheral surface and rotating together with a wheel, and an electromagnetic pickup sensor arranged to face the outer peripheral surface of the rotor.

With the above arrangement, the electromagnetic pickup sensor outputs different signals depending on whether the electromagnetic pickup sensor faces the concave portion or the convex portion of the rotor. The unevenness of the rotor is formed so that the concave portion and the convex portion are inverted at every predetermined rotation angle. Therefore, the electromagnetic pickup sensor outputs one pulse signal each time the wheel rotates by a predetermined rotation angle.

As described above, according to the above configuration, it is possible to realize a device that outputs a pulse signal every time the wheel rotates by a predetermined angle. The time required for the wheel to rotate by a predetermined angle changes depending on the rotational speed of the wheel. In other words, the rotation speed of the wheel can be detected based on the time required for the wheel to rotate by a predetermined angle. Therefore, according to the above-mentioned conventional device, it is possible to detect the rotational speed of the wheel based on the cycle in which the pulse signal is output.

[0005]

By the way, in the electromagnetic pickup sensor, the distance between the electromagnetic pickup sensor and the outer peripheral surface of the rotor changes when the portion facing the electromagnetic pickup sensor is inverted between the concave portion and the convex portion. Outputs a pulse signal. Therefore, when the distance between the rotor and the electromagnetic pickup sensor changes due to the vibration of the rotor, the pulse signal may be continuously output from the electromagnetic pickup sensor even if the rotor is not rotating.

[0006] As described above, when the device for detecting the wheel speed of the automobile is constructed by using the rotor rotating with the wheel and the electromagnetic pickup sensor facing the rotor, for example, when the vehicle is stopped When the damping is performed, the distance between the electromagnetic pickup sensor and the rotor may periodically expand and contract due to resonance caused by the vibration of the engine. In this respect, the rotation speed detection device configured as described above has a possibility of erroneously detecting the rotation speed when the wheel is not rotating.

The present invention has been made in view of the above points, and detects the rotation speed of a rotating body based on a signal output in accordance with the rotation of the rotating body, and the rotating body is notified of the signal. Rotation speed detection that solves the above problems by determining whether or not features that occur only when rotating are superimposed and by determining the authenticity of the detected rotation speed according to the determination result. The purpose is to provide a device.

[0008]

The above object is achieved by the present invention.
As described above, a rotor having an uneven surface that rotates together with a rotating body, an unevenness detection sensor that is disposed at a position facing the uneven surface, and that outputs a signal according to the distance to the uneven surface, In a rotation speed detection device including a rotation speed calculation unit that calculates the rotation speed of the rotating body based on a fluctuation cycle, it is determined whether or not a characteristic generated by the rotation of the rotor is superimposed on the signal. And a normal value recognition unit that recognizes the rotation speed calculated by the rotation speed calculation unit as a normal value when the characteristics are superimposed on the signal. To be done.

In the present invention, when the rotating body rotates and, as a result, the rotor rotates, the unevenness detecting sensor outputs a periodic signal. The unevenness detection sensor also outputs a periodic signal when the distance between the rotor and the unevenness detection sensor changes due to disturbance such as vibration. The rotation speed calculation means calculates the rotation speed of the rotating body based on these signals. By the way, when the unevenness detection sensor outputs a signal in accordance with the rotation of the rotor, a characteristic indicating that the rotor is rotating is superimposed on the signal. The feature determining means is
When the feature is superimposed on the signal output from the unevenness detection sensor, the rotation speed calculated based on the signal is recognized as a normal value. As a result, the inconvenience that the rotation speed calculated due to the disturbance such as vibration is recognized as a normal value is avoided.

Further, the above object is, as described in claim 2, in the rotation speed detecting device according to claim 1,
While the uneven surface is eccentric with respect to the rotating body, the feature determining means, in the signal, based on whether or not a predetermined undulation due to the eccentricity of the rotating body has occurred, to the signal It is also achieved by a rotation speed detection device that determines whether or not the features are superimposed.

In the present invention, the uneven surface that rotates with the rotating body is eccentric with respect to the rotating body. Therefore, when the rotor is rotating, the undulation due to the eccentricity of the uneven surface is superimposed on the signal output from the unevenness detection sensor. On the other hand, when the distance between the rotor and the unevenness detection sensor periodically changes due to disturbance, the swell is not superimposed on the signal output from the unevenness detection sensor. The feature determining means accurately determines whether the signal output from the concave-convex detection sensor has undulations or not due to the rotation of the rotating body or a disturbance such as vibration. Determine whether.

[0012]

FIG. 1 shows a system configuration diagram of an embodiment of the present invention. The system of this embodiment includes front and rear wheels 12FL, 12FR, 12RL,
12RR (Hereinafter, wheels 12 ** when collectively referred to
(Hereinafter referred to as "rotation speed") Vw _FL , Vw _FR , Vw _RL , Vw
A rotation speed detection device for detecting _RR (hereinafter collectively referred to as rotation speed Vw _** ) is provided.

The rotation detecting device is composed of wheel speed sensors 14FL, 14FR, 14 provided on each wheel 12 **.
RL, 14RR (hereinafter, these are collectively referred to as wheel speed sensor 14 **), and electronic control unit 16
(Hereinafter, referred to as ECU 16). The output signal of the wheel speed sensor 14 ** is supplied to the ECU 16. The ECU 16 detects the rotation speed Vw _** of each wheel 12 ** based on the output signal of the wheel speed sensor 14 **.

A speedometer 18 arranged in the vehicle compartment is connected to the ECU 16. The ECU 16 estimates the vehicle body speed V based on the rotation speed Vw _** of each wheel 12 **.
_SP is calculated by calculating _SO and generating an electric signal corresponding to V _SO.
8 The speedometer 18 receives the electric signal and displays the vehicle speed SPD in the vehicle compartment.

The vehicle 10 is a front engine / front drive type vehicle (FF vehicle). Therefore, the left and right front wheels FL, FR are steered wheels, and the left and right rear wheels RL,
RR is used as a drive wheel. An engine 20 is mounted on the vehicle 10. The output shaft of the engine 20 is connected to the transmission 22. The output shaft of the transmission 22 is connected to the left and right rear wheels RL and RR via a drive shaft 24. The output torque of the engine 20 and the vibration of the engine 20 are transmitted to the left and right rear wheels RL and RR that are the driving wheels via the transmission 22 and the drive shaft 24.

The wheel speed sensor 14 ** is the wheel 12 **.
A rotor that rotates together with the rotor and an electromagnetic pickup sensor that is disposed so as to face the outer circumference of the rotor are provided. Less than,
These structures will be described with reference to FIGS. Since the four wheel speed sensors 14 ** are the same in structure, the structure of the wheel speed sensor 14RR will be described here as a representative example thereof.

FIG. 2 is a perspective view showing the vicinity of the wheel speed sensor 14RR as viewed from the arrow II shown in FIG. As shown in FIG. 2, a rotor 28, which is a component of the wheel speed sensor 14RR, is fixed to the tip end of the drive shaft 24 together with the disk rotor 26. Disk rotor 2
6 and the rotor 28 are members that rotate together with the wheel 12RR.

On the outer peripheral surface of the rotor 28, an uneven surface 28 composed of a plurality of concave portions and convex portions which are repeated at predetermined intervals is provided.
a is formed. An electromagnetic pickup sensor 30 is provided at a position facing the uneven surface 28a. The electromagnetic pickup sensor 30 is fixed to a member on the vehicle body side so that a predetermined gap is formed between the electromagnetic pickup sensor 30 and the uneven surface 28a.

FIG. 3 shows the principle configuration of the wheel speed sensor 14RR. As shown in FIG. 3, the electromagnetic pickup 30
Includes a pickup coil 32 arranged to face the rotor 28, and a permanent magnet 34 that generates a magnetic flux penetrating the pickup coil 32. The rotor 28, the pickup coil 32, and the permanent magnet 34 are arranged on the rotor surface 2
When the convex portion of 8a faces the pickup coil 32,
Most of the magnetic flux emitted from the permanent magnet 34 recirculates through the inside of the pickup coil 32 and the rotor 28, and most of the magnetic flux emitted from the permanent magnet 34 when the concave portion of the rotor surface 28a faces the pickup coil 32. Are arranged so as to flow back without passing through the inside of the pickup coil 32.

According to the above structure, the density of the magnetic flux penetrating the pickup coil 32 depends on whether the convex portion of the rotor surface 28a faces the pickup coil 32 or not.
It changes depending on whether the concave portion of is opposed to the pickup coil 32. When the density of the magnetic flux penetrating the pickup coil 32 changes, a counter electromotive force that suppresses the change is generated in the pickup coil 32.

As described above, the rotor surface 28a is formed with the concave portions and the convex portions repeatedly at predetermined intervals. Therefore, when the rotor 28 rotates, the situation where the convex portion faces the pickup coil 32 and the situation where the concave portion faces the pickup coil 32 are switched every time the rotor 28 rotates by a predetermined angle. Then, a back electromotive force is generated at both ends of the pickup coil 32 each time such switching occurs.

FIG. 4 shows changes in the voltage signal generated across the pickup coil 32 as the rotor 28 rotates. The solid line curve in FIG. 4 shows the output change when the rotor 28 rotates at high speed. The curve indicated by the broken line in FIG. 4 shows the output change when the rotor 28 rotates at a low speed. As described above, a voltage signal that repeatedly increases and decreases each time the rotor 28 rotates by a predetermined angle is output to both ends of the pickup coil 32. Therefore, as shown in FIG.
The voltage signal appearing at both ends of the pickup coil 32 shows a fluctuation period according to the rotation speed of the rotor 28.

In this embodiment, the ECU 16 controls each wheel
At both ends of the pickup coil 32 of the speed sensor 14 **
The corresponding wheel 1 is based on the fluctuation period of the generated voltage signal.
2 ** rotation speed Vw_**Is detected. And ECU1
6 is their rotation speed Vw _**Based on known hands
The estimated value of the traveling speed SPD of the vehicle 10 using the method
Estimated vehicle speed V_S0Is calculated and the electricity according to the calculated value is calculated.
The signal is supplied to the speedometer 18.

By the way, various vibrations are transmitted to the vicinity of the wheel speed sensor 14 ** even when the vehicle 10 is stopped. Particularly, as described above, the vibration of the engine 20 is directly transmitted to the wheel speed sensors 14RL and 14RR arranged on the left and right rear wheels RL and RR, as described above. Then, for example, when the engine 20 is emptied (hereinafter referred to as racing) while the vehicle 10 is stopped, resonance occurs near the wheel speed sensor 14 ** and the wheel speed sensor 14 ** is generated. There is a situation in which the distance between the rotor 28 and the electromagnetic pickup sensor 30 that compose 14 ** is large and continuously expanded and contracted.

FIG. 5 shows changes in signals output from the wheel speed sensor 14RR when resonance vibration occurs near the wheel speed sensor 14RR due to racing performed while the vehicle 10 is stopped. As described above, the wheel speed sensor 14RR generates a signal according to the rotation speed Vw _RR by utilizing the fact that the density of the magnetic flux penetrating the pickup coil 32 is increased or decreased as the rotor 28 rotates. .

The density of the magnetic flux penetrating the pickup coil 32 changes as the rotor 28 rotates, and
It also varies as the distance between the rotor 28 and the pickup coil 32 expands and contracts. For this reason, when resonance vibration occurs near the wheel speed sensor 14RR, the wheel speed sensor 14RR will be able to operate even if the rotor 28 is not rotating as shown in FIG.
As shown in, a signal that repeatedly increases and decreases in the cycle of the resonance vibration is output.

Although the rotor 28 is stopped,
As described above, the signal output from the wheel speed sensor 14RR is similar to the signal output from the wheel speed sensor 14 ** in accordance with the rotation of the rotor 28 in that the increase / decrease is repeated at a certain appropriate cycle. Therefore, all the signals output from the wheel speed sensor 14 ** are directly transmitted to the wheel 1
When converting the rotational speed Vw _** 2 **, so that the disadvantage that the rotational speed Vw _** for the wheel 12 ** generating no rotation is detected is generated.

All the wheels 12 * are avoided by avoiding the above inconvenience.
* Always accurate rotation speed Vw _**To seek
Is a wheel speed sensor based on the rotation of the wheels 12 **.
The signals output from 14 ** and the wheels 12 ** stop.
However, due to disturbances such as racing,
The signal output from the wheel speed sensor 14 **
It is necessary to treat them separately. Rotational speed test of this example
The output device is a signal output from the wheel speed sensor 14 **
The feature that appears only when the wheels 12 ** are rotating
By judging whether or not they are overlapped,
It has a function that enables another. Below, such features
Will be described.

As described above, the wheel speed sensor 14RR is
It comprises a rotor 28 which rotates with the wheels 12 **.
The concavo-convex surface 28a of the rotor 28 is in an eccentric state with respect to the rotation axis of the wheel 12 ** due to an error in manufacturing or assembling, or intentionally designed. If the uneven surface 28a is eccentric with respect to the rotation axis of the wheel 12 **, one cycle of the wheel 12 ** makes one cycle, and the distance between the uneven surface 28a and the pickup coil 32 is the rotation of the wheel 12 **. Fluctuates slowly with.

FIG. 6 shows a change in the signal output from the wheel speed sensor 14 ** when the distance between the uneven surface 28a and the pickup coil 32 changes as described above with the rotation of the wheel 12 **. . The strength of the magnetic flux penetrating the pickup coil 32 is such that the uneven surface 28 a
The distance changes greatly as the distance passes closer, and decreases as the distance between the uneven surface 28a and the pickup coil 32 increases. Therefore, when the distance between the uneven surface 28a and the pickup coil 32 changes gently, as shown in FIG.
The signal intensity output from the pickup coil 32 also undergoes a gentle fluctuation (hereinafter, this fluctuation is referred to as undulation).

Therefore, in the system of this embodiment,
When a signal that periodically changes is issued from the wheel speed sensor 14 **, by determining whether or not a predetermined swell is superimposed on the signal, the wheel speed sensor 14 **
It is possible to accurately determine whether the signal emitted from ** is due to the rotation of the wheels 12 ** or due to a disturbance such as racing.

FIG. 7 shows an example of a control routine executed by the ECU 16 to specify the magnitude of the swell superimposed on the signal output from the wheel speed sensor 14 ** in order to realize the above-mentioned function. A flow chart is shown. The routine shown in FIG. 7 is performed by the wheel speed sensor 14 *.
It is executed for each of *.

When the routine shown in FIG. 7 is started, first, at step 100, the signal V _** output from the wheel speed sensor 14 _** is input. As mentioned above, the signal V
_** is a signal indicating periodic vibration due to rotation of the wheel 12 ** or due to resonance vibration in the vicinity of the wheel speed sensor 14 **.

In step 102, the signal V_**Derivative of d
V_**/ dt is calculated. Differential value dV _**/ dt is the last
Signal V detected at the time of processing_**Value and the signal detected this time
V_**It is calculated based on the difference from the value of. Step 104
Then dV_**It is determined whether / dt = 0 holds.
The above-mentioned condition is the signal V that repeats periodic increase and decrease._**The value of the
Holds when the peak value of the upper limit or the lower limit is shown.
You. When the above conditions are not satisfied, that is, the signal V
_**If it is judged that the value of is not the peak value, repeat
The processing from step 100 onward is executed. EC
U16 uses the signal V_**Fluctuation of
To be executed repeatedly at a sufficiently short time compared to the period
This routine is executed. On the other hand, dV_**/ dt = 0 holds
If so, the process of step 106 is executed next.
Is done.

In step 106, the above step 104
When the condition of is satisfied, the wheel speed sensor 14 ** outputs
The value V of the applied signal_**However, the
Value A_(n)Is stored as In step 108,
Peak value A detected this time_(n)And detected during the previous processing
Peak value A_(n-1)Whether the product of and is a positive value
Or the peak value A _(n)Sign and peak value A
_(n-1)It is determined whether or not the same as the sign of. Book
In accordance with the above determination result, the peak value A_(n)
And peak value A_(n-1)A method to find the average value of
You.

The peak value A _(n) and the peak value A _(n-1) are
It is a set of peak values on the lower limit side and the upper limit side that are continuously detected. FIG. 8 shows a case where the peak value A _(n-1) is detected as the lower limit peak value, the peak value A _(n) is detected as the upper limit peak value, and both have different signs. As shown in FIG. 8, peak value A _(n) and peak value A
_When the signs of _(n-1) are different, their average value can be obtained by adding both. Therefore, if it is determined in step 108 that A _(n) * A _(n-1) > 0 is not satisfied, then in step 110, A _(n) + A _{(n-1 )} is the average of both. It is stored in the memory B as a value.

FIG. 9 shows a case where the peak value A _(n-1) is detected as the lower limit peak value, the peak value A _(n) is detected as the upper limit peak value, and both have the same sign. It represents. When the peak value A _(n) and the peak value A _(n-1) have the same sign as shown in FIG.
The average value can be obtained by dividing by. Therefore, in step 108, A _(n) * A _(n-1) > 0
If it is determined that the above condition holds, then in step 112, {A _(n) + A _(n-1) } / 2 is stored in the memory B as the average value of both.

The average value of the peak value A _(n) and the peak value A _(n-1) stored in the memory B is from "0" so that a large difference occurs between two continuously detected peak values. The values are far apart. The fluctuation range of the peak value of the signal V _** is
It corresponds to the size of the swell of _** . Therefore, the value stored in the memory B in this system is the signal V
It can be understood as the characteristic value of the swell magnitude of _** .

Therefore, the above step 110 or 11
When the process of 2 is completed, next in step 114,
The value stored in the memory B, that is, the peak value A
The average value of _(n) and the peak value A _(n) is stored as the magnitude of the swell of the signal V _** . When the process of step 114 is completed, the process of replacing the value of the peak value A _(n) with A _(n-1) is performed in step 116, and then this routine is ended.

FIG. 10 shows that the signal generated from the wheel speed sensor 14 ** is caused by the rotation of the wheel 12 ** based on the magnitude of the swell of the signal V _** , or The flowchart of an example of the control routine which ECU16 performs in order to determine whether it is caused by a disturbance such as racing is shown.

When the routine shown in FIG. 10 is started,
Without step 200, the signal V _**Size of swell
Is entered. The process of inputting the amount of undulation ends
Then, in step 202, the waviness is a predetermined threshold.
It is determined whether it is smaller than a certain value Vth + (> 0).
As a result, when it is determined that the swell <Vth + is established
In step 204, the swell
It is determined whether or not the value is larger than the predetermined value Vth-(<0).

As described above, the swell is superimposed on the signal V _** output by the rotation of the wheels 12 **.
The threshold values Vth + and Vth− used in steps 202 and 204 above do not satisfy Vth− <waviness <Vth + when the swell is superposed on the signal V _** , and the swell does not occur in the signal V _**. V if not superimposed on _**
The value is set so that th- <waviness <Vth + is satisfied.

Therefore, in the above step 202, the swell <V
When it is determined that th + does not hold, and when the swell> Vth- does not hold in step 204, the signal V _** output from the wheel speed sensor 14 _** changes to the wheel 12 *. It can be determined that it is due to the rotation of *. Therefore, if the above determination is made, then in step 210, the flag Frcg is reset to "0" to indicate that the signal V _** is not caused by a disturbance such as racing.

On the other hand, when it is determined by the processing of steps 202 and 204 that Vth- <waviness <Vth + is established, the signal V _** output from the wheel speed sensor 14 ** is a disturbance such as racing. It is necessary to judge that there is a possibility that Therefore, when the above determination is made, the process of step 206 is further executed in order to further analyze the cause of the generation of the signal V _** .

In step 206, the estimated vehicle body speed V _S0 calculated based on the rotation speed Vw _** of the wheels 12 ** is 3
It is determined whether the speed is less than km / h. According to the system of this embodiment, when the signal V _** is output due to a disturbance such as racing, the estimated vehicle body speed V _S0 of 3 km / h or more is obtained.
Is never calculated. Therefore, when it is determined that V _S0 <3 km / h is not established, it can be determined that the signal V _** is not due to racing. In this case, the routine of this time is ended after the processing of step 210 is executed thereafter.

On the other hand, in step 206, V _S0
If it is determined that <3 km / h is established, it can be determined that the signal V _** is due to racing. In this case, thereafter, in step 208, the flag Frcg is set to "1", and then this routine is ended.

According to the above processing, if the signal V _** is generated due to disturbance such as racing, the flag Fr
It is possible to set cg to "1" and to set the flag Frcg to "0" when the signal V _** is generated due to the rotation of the wheels 12 **. Therefore, according to the system of this embodiment, by monitoring the state of the flag Frcg, the signal V _** output from the wheel speed sensor 14 ** as the wheel 12 ** rotates and the disturbance such as racing. Therefore, the signal V _** output from the wheel speed sensor 14 ** can be appropriately distinguished and handled.

FIG. 11 shows a flowchart of an example of a control routine executed by the ECU 16 to calculate the vehicle speed SPD output to the speedometer 18. The routine shown in FIG. 11 is a periodic interruption routine that is started every predetermined time. When the routine shown in FIG. 11 is started, the process of step 300 is first executed.

In step 300, the wheel speed sensor 14
The rotation speed Vw _** of the wheel 12 ** calculated based on the cycle of the signal V _** output from _** is input. When the input processing of the rotation speed Vw _** is completed, next step 302
Is performed. In step 302, the estimated vehicle body speed V _SO is calculated based on the rotation speed Vw _** of the wheels 12 ** by a known method. When the calculation of the estimated vehicle body speed V _S0 is completed, the process of step 304 is executed next.

At step 304, it is judged if the flag Frcg is "0". When Frcg = 0 holds, it can be determined that the rotation speed Vw _** input in step 300 above truly represents the rotation speed of the wheels 12 **. In this case, after this, step 306
At, the estimated vehicle body speed V _S0 is output to the speedometer 18 as the vehicle speed SPD, and then this routine is ended.

On the other hand, in step 304, Frcg = 0
If it is determined that is not established, the above step 30
The rotational speed Vw _** input at 0 can be determined to be an error caused by a disturbance such as racing. In this case, thereafter, in step 308, the vehicle speed SPD = 0 km
After / h is output to the speedometer 18, this routine is ended.

According to the above processing, it is possible to surely avoid the inconvenience that the vehicle speed SPD is erroneously displayed on the speedometer 18 due to a disturbance such as racing while the vehicle is stopped. By the way, in the system shown in FIG. 1, only the speedometer 18 for displaying the vehicle speed SPD is displayed as the device for receiving the signal related to the vehicle speed SPD, but the device for receiving the signal representing the vehicle speed SPD is not limited to this. Not a thing. That is, the vehicle speed SPD is a parameter widely used for vehicle control such as engine control and transmission control. If the vehicle speed SPD in which the influence of racing or the like is eliminated as described above is supplied to the electromagnetic control device that controls these vehicles, the vehicle control can be performed with higher accuracy.

Also, in the above embodiment, the signal V _**
The magnitude of the swell that is superimposed on the signal V _** is detected based on the average value of two peak values A _(n) and A _(n-1) that are continuously detected. The method of detecting the size of the swell is not limited to this. That is, based on the center of the waveform obtained by integrating the signal V _**, or based on the variation of the absolute value of the peak value of the signal V _**, the undulations superimposed on the signal V _** size May be detected.

Further, in the above embodiment, the rotor 28 of the wheel speed sensor 14 ** rotates eccentrically with respect to the wheel 12 **, or the rotor 28 is rotated with respect to the wheel 12 **. by rotating eccentrically consciously Te, features associated with the rotation of the rotor 28 although the be superimposed on the signal V _**, techniques to superimpose the features associated with the rotation of the signal V _** in the rotor 28 in this It is not limited. That is, for example, the uneven surface 28a of the rotor 28
It is also possible to change the height of the convex portion formed in the above, or to make the rotor 28 have an elliptical shape, so as to superimpose the characteristics accompanying the rotation of the rotor 28 on the signal V _** .

In the above embodiment, the wheels 12 *
* Indicates the "rotating body" described in claim 1, and the electromagnetic pickup sensor 30 indicates the "unevenness detection sensor" described in claim 1.
And the ECU 16 outputs the signal V
By calculating the rotation speed Vw _** based on _** , the "rotation speed calculation means" according to claim 1 is configured so that the ECU 16 executes the routine shown in FIG. 7 and steps 200 to 204 shown in FIG. By executing the processing, the "feature determining means" described in claims 1 and 2 and the "normal value recognition means" described in claim 1 by performing the processing of step 210 shown in FIG. Each has been realized.

[0056]

As described above, according to the first aspect of the present invention, the disturbance caused by the disturbance is distinguished by distinguishing the signal outputted by the rotation of the rotor from the vibration outputted by the disturbance such as vibration. It is possible to avoid the inconvenience of erroneously recognizing the calculated rotation speed as a normal value. Therefore, according to the rotation speed detection device of the present invention, an accurate rotation speed can be detected without being affected by disturbance.

According to the second aspect of the present invention, the signal output from the unevenness detection sensor is output based on whether the undulation due to the eccentricity of the uneven surface is superimposed on the signal output from the unevenness detection sensor. It is possible to accurately determine whether the existing signal is due to the rotation of the rotating body or due to a disturbance such as vibration. Therefore,
According to the rotation speed detection device of the present invention, an accurate rotation speed can be detected without being affected by disturbance.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention.

FIG. 2 is a perspective view showing the vicinity of a wheel speed sensor as viewed in the direction of arrow II shown in FIG.

FIG. 3 is a principle configuration diagram of a wheel speed sensor.

FIG. 4 is a diagram showing a waveform of a signal output from a wheel speed sensor.

FIG. 5 is a diagram showing a waveform of a signal output from a wheel speed sensor due to a disturbance such as racing.

FIG. 6 is a diagram showing a waveform of a signal output from a wheel speed sensor when a wheel rotates.

FIG. 7 is a flowchart of an example of a control routine executed to detect the magnitude of undulations superimposed on a signal.

FIG. 8 is a diagram showing a waveform of a signal when peak values having different signs are continuously detected.

FIG. 9 is a diagram showing a waveform of a signal when peak values having the same sign are continuously detected.

FIG. 10 is a flowchart of an example of a control routine that is executed to determine whether the cause of the signal is wheel rotation or a disturbance such as racing.

FIG. 11 is a flowchart of an example of a control routine executed to calculate a vehicle speed SPD displayed on a speedometer.

[Explanation of symbols]

10 vehicles 12FL, 12FR, 12RL, 12RR, 12 **
Wheels 14FL, 14FR, 14RL, 14RR, 14 **
Wheel speed sensor 16 Electronic control unit (ECU) 18 Speedometer 20 Engine 22 Transmission 24 Drive shaft 28 Rotor 28a Uneven surface 30 Electromagnetic pickup 32 Pickup coil 34 Permanent magnet

Claims (2)

[Claims] 1. A rotor having an uneven surface that rotates together with a rotating body, an unevenness detection sensor that is disposed at a position facing the uneven surface, and that outputs a signal according to the distance to the uneven surface, In a rotation speed detection device including a rotation speed calculation unit that calculates a rotation speed of the rotating body based on a fluctuation cycle, it is determined whether or not a characteristic caused by the rotation of the rotor is superimposed on the signal. And a normal value recognition unit that recognizes the rotation speed calculated by the rotation speed calculation unit as a normal value when the feature is superimposed on the signal. Speed detector. 2. The rotation speed detecting device according to claim 1, wherein the uneven surface is eccentric with respect to the rotating body, and the feature determining means causes the signal to be caused by eccentricity of the rotating body. Based on whether a predetermined swell occurs,
A rotation speed detection device, characterized in that it is determined whether or not the feature is superimposed on the signal.