JP2002090179A - Rotation detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an absolute wheel rotation angle, and to detect the rotation direction of the wheel. SOLUTION: A rotor 2 is subjected to tooth form reshaping so as to have a higher-order random code in addition to teeth placed at fixed intervals. For example, assuming that a conventional rotor 2 is formed by arranging plural teeth 1 at fixed intervals, a formation in which the teeth 1 having narrower width than hitherto are partially provided is adopted, to thereby obtain the higher-order random code at this part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation detecting device for detecting a rotation angle, a rotation direction, a wheel speed, and the like of a wheel based on a rotor having a plurality of teeth that rotate together with the wheel.

[0002]

2. Description of the Related Art Conventionally, a rotor having teeth at regular intervals that rotates with an axle,
Using a sensor unit provided on the rotor that converts changes in the peaks (convex portions) and valleys (concave portions) of the teeth into signals, a periodic signal per unit time is obtained based on a signal from the sensor unit. The wheel speed is calculated by obtaining the number of teeth passed per unit time from the periodic signal.

[0003] However, since the teeth provided on the rotor are arranged at regular intervals, even if the relative wheel rotation angle can be detected several times from the start of the detection, even if the relative wheel rotation angle can be detected from a certain position of the wheel. The absolute wheel rotation angle could not be detected many times.

Further, since the teeth are arranged at regular intervals, the output signal of the sensor section has the same waveform both when the vehicle is moving forward and when the vehicle is moving backward, and it is not possible to detect the rotation direction of the wheels.

In view of the above, it is an object of the present invention to provide a rotation detecting device capable of detecting an absolute wheel rotation angle. It is another object of the present invention to detect the rotation direction of a wheel.

[0006]

In order to achieve the above object, according to the present invention, a plurality of teeth (1) are provided.
A rotor (2) that rotates together with the wheels, a sensor unit (3) that generates an output signal in accordance with a change in peaks and valleys of teeth provided on the rotor, and a sensor unit based on the output signal of the sensor unit. A signal processing unit (4) for detecting rotation information;
The rotor is characterized in that the tooth profile of the teeth passing through the sensor section has a different pattern when the wheel is rotating forward and when the wheel is rotating reversely.

As described above, the rotation direction of the wheel can be detected by making the tooth profile of the tooth passing through the sensor section different between the normal rotation and the reverse rotation.

For example, as set forth in claim 2, the signal processing unit includes a rotation direction detecting means (4) for detecting a rotation direction of the wheel.
c), the rotation direction can be detected based on the fact that the output signal output by the sensor unit during normal rotation and the output signal output by the sensor unit during reverse rotation have opposite waveforms.

According to the third aspect of the present invention, a part of the plurality of teeth has an output signal output when some of the teeth pass through the sensor portion, and the other portion of the plurality of teeth has a sensor portion. Is characterized in that the tooth profile is formed so that the frequency of the output signal is higher than that of the output signal that is output when the signal passes through.

As described above, the output signal output when a part of the plurality of teeth passes the sensor unit is higher than the output signal output when the other part of the plurality of teeth passes the sensor unit. In this case, the absolute rotation angle of the wheel can be detected starting from a higher-order frequency.

For example, as set forth in claim 4, a part of the plurality of teeth may have a smaller tooth width than the other teeth.
Further, as shown in claim 5, for a part of the plurality of teeth,
The tooth cut (1g, 1j) may be formed at the tooth peak, or the protrusion (1k) may be formed at the tooth valley.

According to a seventh aspect of the present invention, there is provided a rotor (2) having a plurality of teeth (1) and rotating with wheels.
A sensor unit (3) for generating an output signal corresponding to a change in the peaks and valleys of the teeth provided on the rotor, and a signal processing unit (4) for detecting rotation information based on the output signal of the sensor unit. The plurality of teeth are characterized in that some of the teeth have a smaller tooth width than the other teeth. This allows
The same effect as the third aspect can be obtained.

Further, in the invention according to claim 8,
A rotor (2) having a plurality of teeth (1) and rotating together with wheels, a sensor section (3) for generating an output signal corresponding to a change in peaks and valleys of the teeth provided on the rotor, and a sensor section And a signal processing unit (4) for detecting rotation information based on the output signal of the plurality of teeth. Alternatively, a protrusion (1k) is formed in a tooth valley. Thereby, the same effect as the third aspect can be obtained.

The reference numerals in the parentheses of the above means indicate the correspondence with the specific means described in the embodiments described later.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows an overall configuration of a rotation detecting device to which one embodiment of the present invention is applied. As shown in FIG. 1, a rotation detecting device includes a rotor 2 provided with a plurality of teeth 1 that rotate with an axle,
A sensor unit 3 for converting a change in peaks (convex portions) and valleys (concave portions) of the teeth 1 provided in the sensor 1 into a signal, and an electronic control unit as a signal processing unit for performing various calculations based on output signals of the sensor unit (Hereinafter, referred to as an ECU) 4.

The rotor 2 is shaped so as to have not only regularly spaced teeth but also high-order random codes. For example, assuming that the conventional rotor 2 has a configuration in which a plurality of teeth 1 are arranged at regular intervals, in this embodiment, a tooth having a narrower peak width and valley width (hereinafter referred to as tooth width) than the conventional one. By adopting a configuration in which 1 is partially provided, a high-order random code can be obtained in this portion. Specifically, the arrow A in the figure indicates the direction of rotation of the rotor when the vehicle is moving forward (forward rotation), and the arrow B indicates when the vehicle is moving backward (reverse rotation).
, The tooth shape passing through the sensor unit 3 when the rotor 2 rotates in the direction of arrow A and when viewed in the direction of arrow B are different from each other. When a plurality of teeth 1a at a certain interval pass in front of the sensor unit 3 when the rotation of the tooth 2 occurs, three teeth 1b having a narrower tooth width pass through the teeth 1b, and thereafter, a tooth 1c having a further narrower tooth width. Are configured to pass three.

The sensor section 3 outputs a sinusoidal output signal in accordance with a change in peaks and valleys of the teeth 1 of the rotor 2, and is composed of a known sensor such as an electromagnetic pickup type or a magnetoresistive element (MRE) type. For example, a wheel speed sensor can be used.

The ECU 4 is provided with a wheel speed calculator 4a, a rotation angle detector (rotation angle detector) 4b, and a rotation direction detector (rotation direction detector) 4c.

The wheel speed calculation unit 4a obtains a periodic signal per unit time from the output signal of the sensor unit 3, that is, a rectangular wave signal formed by partitioning the output signal of the sensor unit 3 at a predetermined threshold level. Then, from the periodic signal per unit time, how many teeth 1 have passed through the sensor unit 3 per unit time or the interval of the rising edge of the periodic signal is determined, and the wheel speed is calculated based on these. Is going. At this time, a portion of the periodic signal per unit time having a period shorter than the period of the normal tooth width occurs. Therefore, by masking the portion having the shorter period, the periodic signal based on only the normal tooth 1a is obtained. Similarly to the above, the calculation of the wheel speed can be performed even with the periodic signal obtained in the present embodiment.

The rotation angle detector 4b includes a wheel speed calculator 4
A periodic signal per unit time is sent from a, and the rotation angle detector 4b detects the rotational angle of the wheel based on the periodic signal per unit time. Specifically, as described above, there is a portion where the period is shortened in the periodic signal per unit time, and the number of teeth that have passed through the sensor unit 3 from the start point is defined as the portion where the period is shortened. By counting, the absolute wheel rotation angle can be detected. That is, since the rotation angle is determined by the number of teeth that have passed through the sensor unit 3 with respect to the total number of teeth 1 provided on the rotor 2, by counting the number of teeth that have passed through the sensor unit 3 from the above-mentioned starting point, the wheel from the starting point can be counted. The rotation angle can be detected.

The wheel speed calculation unit 4 is also provided in the rotation direction detection unit 4c.
The periodic signal per unit time is sent from a. The rotation direction detector 4c detects the rotation direction of the wheel based on the periodic signal per unit time. Specifically, as described above, since the period signal per unit time includes a portion having a shorter period, the rotation direction of the wheel is detected based on the shorter period. When the rotor 2 having the tooth profile as in the present embodiment is used, if the rotor 2 rotates in the direction of the arrow A, the period of the normal tooth width continues, and then the portion where the period becomes shorter continues three times. The part where the cycle becomes shorter continues three times. Conversely, if the rotor 2 rotates in the direction of the arrow B, a portion with a shorter period continues three times, and then a portion with a longer period continues three times, and then a normal tooth width longer than that. The cycle will continue. For this reason, the rotation direction of the wheel can be detected by detecting a portion where the period is shorter than that of the normal tooth width.

FIG. 2 is a timing chart showing the operation of the rotation detecting device according to the present embodiment, and a specific operation will be described with reference to FIG. (A), (b), and (c) in FIG. 2 show timing charts when the vehicle is moving forward, when the vehicle is moving backward, and when the vehicle is running at a low speed, respectively.
In each case, the tooth profile of the rotor 2 passing through the sensor unit 3 and the waveform of the output signal of the sensor unit 3 with respect to the tooth profile of the rotor 2 are shown.

As shown in FIGS. 2A and 2B, the portion of the rotor 2 whose tooth width is reduced is the sensor portion 3.
, An output signal having a shorter period than that of the normal tooth width portion is generated. As described above, since the output signal of the sensor section 3 includes a portion having a short cycle, the absolute rotation angle of the wheel can be detected starting from this portion. Further, since the sensor unit 3 generates different output signals when the vehicle advances and when the vehicle moves backward, the rotation direction of the wheel can be detected based on the output signal of the sensor unit 3. Further, by masking a short portion of the output signal of the sensor unit 3, the wheel speed can be detected.

Since the amplitude of the output signal of the sensor unit 3 increases as the vehicle speed increases, the output signal of the sensor unit 3 can be partitioned at a predetermined threshold level when the vehicle speed is higher than a certain level. Can be detected, but when the vehicle is running at a low speed, the amplitude at the normal tooth width may not be able to be divided at the threshold level.

However, as shown in FIG. 3 (c), since the portion where the tooth width is narrower than the normal tooth width is formed, the amplitude of the output signal of the sensor section 3 is large in that portion. And can be partitioned at a threshold level (indicated by a dashed line in the figure). Therefore, even when the vehicle is running at a low speed, the rotation angle and the rotation direction of the wheels can be detected.

(Second Embodiment) In this embodiment, by using a rotor 2 having a tooth profile different from that of the first embodiment,
Detects the rotation angle and direction of the wheels. FIG. 3 shows the entire configuration of the rotation detecting device according to the present embodiment. Since the basic configuration of the rotor 2 other than the tooth profile is the same as that of the first embodiment, only different portions will be described.

Also in this embodiment, the rotor 2 is shaped so as to have not only the teeth 1a at regular intervals but also a high-order random code. For example, the conventional rotor 2
Is a configuration in which 48 teeth are arranged at regular intervals, in the present embodiment, a plurality of teeth are cut (provided with recesses) to divide the teeth into two teeth 1d, and a high The next random code is obtained. Specifically, with respect to a certain point (here, the tooth 1e) on the outer periphery of the rotor 2 as a center, the tooth shape when viewed from the center in the direction of arrow A and the tooth shape when viewed in the direction of arrow B are different. In this embodiment, the first and second parts are divided into two parts from the center when viewed in the direction of arrow A, and the first part is divided into two parts from the center when viewed in the direction of arrow B. I am trying to do it.

FIG. 4 is a timing chart showing the operation of the rotation detecting device according to the present embodiment. The rotation detecting device according to the present embodiment will be described with reference to FIG.

FIG. 4 shows the rotor 2 passing through the sensor section 3.
, The output signal of the sensor unit 3 with respect to the tooth profile of the rotor 2, and the period obtained from the signal obtained by differentiating the output signal of the sensor unit 3 are shown. This figure corresponds to the case where the rotor 2 rotates in the direction of arrow A in FIG.

As shown in this figure, the teeth 1 of the rotor 2
When the part having the gear cut passes through the sensor part 3, the sensor part 3 generates an output signal having a cycle twice as long as the part without the gear cut. Based on this, if the rising edge interval of the output signal of the sensor unit 3 is the width of a portion where normal gear cutting is not performed, the period is set to Hi level, and if the edge interval is narrower than that, the period is set to Low level. expressed. The direction of rotation of the wheels can be detected by the manner in which the cycle changes. That is, when the rotor 2 rotates in the direction of the arrow A, the level becomes Low for one cycle and then becomes the Low level for two cycles, and when the rotor 2 rotates in the direction of the arrow B, the level becomes Low for two cycles. After that, the signal becomes the Low level for one cycle, so that the rotation direction of the wheel can be detected based on this.

As described above, the same effects as in the first embodiment can be obtained by using the toothed rotor 2 as in the present embodiment.

(Third Embodiment) In this embodiment, by using a rotor 2 having a tooth profile different from that of the first embodiment,
Detects the rotation angle and direction of the wheels. The rotor 2
Since the basic configuration other than the tooth shape is the same as that of the first embodiment, only different portions will be described.

FIG. 5 is a timing chart showing the operation of the rotation detecting device according to the present embodiment, and the rotation detecting device according to the present embodiment will be described with reference to FIG.

FIG. 5 shows the rotor 2 passing through the sensor unit 3.
, The output signal of the sensor unit 3 with respect to the tooth profile of the rotor 2, the signal obtained by differentiating the output signal of the sensor unit 3, and the period obtained from the signal obtained by differentiating the output signal of the sensor unit 3 are shown.

The tooth 1f of the rotor 2 has a tooth cut 1g which is shallower than a valley at the peak of the tooth 1f. This shallow gear cut 1g is equivalent to the tooth 1f
Are formed at positions shifted from the center of the mountain, so that the patterns are different when the vehicle is moving forward and when the wheel is moving backward.

When the rotor 2 having such a tooth profile is used, the output signal of the sensor unit 3 has a shape in which the sine waveform is distorted at the portion where the gear cutting 1g is formed. However, even if the output signal becomes distorted in this way, when the wheel speed calculation unit 4a obtains the periodic signal, the distorted part is partitioned at the threshold level, and is similar to the output signal when there is no gear cutting. Can be obtained. Therefore, based on this periodic signal, the calculation of the wheel speed can be performed as in the conventional case.

On the other hand, by differentiating the output signal of the sensor section 3, the slope of the output signal is detected. For this reason,
It is possible to detect that the portion where the gear cutting 1g is formed has passed through the sensor unit 3 based on, for example, the rising edge interval of the output signal of the sensor unit 3 differentiated. Thereby, starting from the portion where the gear cutting 1g is formed,
An absolute wheel rotation angle can be detected.

Further, the position where the gear cutting 1g is formed is defined as the tooth 1
Because it is formed at a position shifted from the center of the mountain of f,
The output signal of the sensor unit 3 has an opposite shape between when the vehicle is moving forward and when the wheel is moving backward. Therefore, the shape of the derivative of the output signal of the sensor unit 3 is reversed between when the vehicle is moving forward and when the wheel is moving backward, and based on this, the rotation direction of the wheel can be detected.

(Fourth Embodiment) In the present embodiment, the first,
By using the rotor 2 having a tooth profile different from that of the second embodiment, the rotation angle and the rotation direction of the wheel are detected. In addition,
Since the basic configuration of the rotor 2 other than the tooth profile is the same as that of the first embodiment, only different portions will be described.

FIG. 6 is a timing chart illustrating the operation of the rotation detecting device according to the present embodiment. The rotation detecting device according to the present embodiment will be described with reference to FIG.

FIG. 6 shows the rotor 2 passing through the sensor unit 3.
, The output signal of the sensor unit 3 with respect to the tooth profile of the rotor 2, the signal obtained by differentiating the output signal of the sensor unit 3, and the period obtained from the signal obtained by differentiating the output signal of the sensor unit 3 are shown.

The teeth 1h and 1i of the rotor 2 are formed with teeth 1j which are shallower than the valleys, and the valleys are formed with protrusions 1k which are smaller than the valleys. The numbers of the gear cuts 1j and the protrusions 1k are changed with respect to the rotation direction of the rotor 2. In this embodiment, the number of the gear cuts 1j and the protrusions 1k is three (the tooth 1h). Are arranged, and three portions (two teeth 1i) each having two gear cuts 1j and protrusions 1k are arranged so as to have different patterns when the vehicle moves forward and when the wheels move backward. .

Also in the case where such a rotor 2 is used, as in the third embodiment, when the wheel speed calculation section 4a obtains the periodic signal, the distorted portion of the output signal of the sensor section 3 is set to the threshold level. Therefore, the calculation of the wheel speed can be performed based on the obtained periodic signal in the same manner as in the related art.

The output signal of the sensor section 3 is differentiated, for example, based on the rising edge interval.
It is possible to detect that the portion where j and the protrusion 1k are formed has passed through the sensor unit 3. Thus, the absolute rotation angle of the wheel can be detected starting from the portion where the gear cutting 1j and the protrusion 1k are formed.

Since the output signal of the sensor unit 3 has an opposite shape between when the vehicle is moving forward and when the wheel is moving backward, the shape of the output signal of the sensor unit 3 is also different between when the vehicle is moving forward and when the wheel is moving backward. The rotation direction of the wheel can be detected based on this.

(Other Embodiments) The tooth profile of the rotor 2 may be other than that shown in the first embodiment. Specifically, if an absolute wheel rotation angle is to be detected, any one of a plurality of teeth may be set to a tooth from which a higher-order random code can be obtained, and a wheel rotation direction may be detected. For example, the pattern of the teeth passing through the sensor unit 3 may be different between when the vehicle is moving forward and when the vehicle is moving backward.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an entire configuration of a rotation detection device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a timing chart when the rotation detecting device shown in FIG. 1 operates.

FIG. 3 is a diagram illustrating an entire configuration of a rotation detection device according to a second embodiment of the present invention.

4 is a diagram showing a timing chart when the rotation detecting device shown in FIG. 3 operates.

FIG. 5 is a diagram showing a timing chart at the time of operation of a rotation detecting device according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a timing chart at the time of operation of a rotation detecting device according to a fourth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Teeth, 2 ... Rotor, 3 ... Sensor part, 4 ... ECU, 4a
... Wheel speed calculation section, 4b rotation angle detection section, 4c rotation direction detection section.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masanobu Yamaguchi 1-1-1 Showa-cho, Kariya-shi, Aichi F-Term in Denso Co., Ltd. 2F077 AA27 AA37 AA38 CC02 NN22 PP06 PP14 QQ11 QQ13 QQ15 TT55 TT62

Claims (8)

[Claims] 1. A rotor (2) having a plurality of teeth (1) and rotating together with wheels, and a sensor unit for generating an output signal according to a change in peaks and valleys of the teeth provided on the rotor. (3), and a signal processing unit (4) that detects rotation information based on an output signal of the sensor unit. The rotor is configured such that when the wheel is rotating forward, The rotation detecting device is configured so that the tooth shape of the tooth passing through the sensor unit has a different pattern when and is rotated. 2. The signal processing unit includes a rotation direction detection unit (4c) for detecting a rotation direction of the wheel, and the rotation direction detection unit outputs from the sensor unit during the normal rotation. The rotation detection according to claim 1, wherein the rotation direction is detected based on an output signal and an output signal output by the sensor unit during the reverse rotation having an inverted waveform. apparatus. 3. The output signal output when a part of the plurality of teeth is output when the part of the plurality of teeth passes through the sensor unit.
The tooth shape is formed so that the frequency of the output signal outputted when the other part of the plurality of teeth passes through the sensor unit is higher than that of the output signal. The rotation detecting device as described in the above. 4. The rotation detecting device according to claim 3, wherein a part of the plurality of teeth has a smaller tooth width than the other teeth. 5. A part of the plurality of teeth includes one of a tooth cut (1g, 1j) formed on a tooth ridge and a protrusion (1k) formed on a tooth valley. 4. The rotation detecting device according to claim 3, wherein the rotation detecting device is both. 6. A rotation angle detecting means (4b) for detecting a rotation angle of the wheel, wherein the signal processing unit is provided with:
The rotation angle detecting means is configured to detect a rotation angle of the wheel starting from a part of the plurality of teeth from which the higher-order frequency is output. 3. The rotation detecting device according to 1. 7. A rotor (2) having a plurality of teeth (1) and rotating with a wheel, and a sensor unit for generating an output signal according to a change in peaks and valleys of the teeth provided on the rotor. (3) and a signal processing unit (4) for detecting rotation information based on an output signal of the sensor unit, wherein the plurality of teeth have a tooth width greater than that of other teeth. A rotation detecting device characterized in that some of the rotation detecting devices are also narrowed. 8. A rotor (2) having a plurality of teeth (1) and rotating with a wheel, and a sensor unit for generating an output signal in accordance with a change in peaks and valleys of the teeth provided on the rotor. (3), and a signal processing unit (4) that detects rotation information based on an output signal of the sensor unit. 1g, 1
j) is formed or the projection (1) is formed in the tooth valley.
a rotation detecting device, wherein either or both of k) and k) are formed.