JPH09210730A - Rotation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation detector by which rotation detection of a rotating body can be accurately performed in a simple constitution. SOLUTION: A rotation detection resistance part 14 is annularly printed on a base face electrode 13 provided on a rotating body 11, and constituted by resistor films 15-20 whose neighboring films are set in different resistance values. When the rotating body 11 is rotated, signals in response to each resistance value of the resistor films 15-20 are changed by stages and output from a detection circuit connected to a slider 21. The number of times in which the signals are changed is counted and a rotation direction can be detected by reading the change quantity of the signals in regard to the rotating angle of the rotating body 11.

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 direction and a rotation angle of a rotating body by using a resistor.

[0002]

Conventionally, as an example of a rotation detecting device for detecting the rotation angle of a rotating body such as a steering wheel of an automobile, a variable resistor type has been provided because it can be inexpensively constructed. ing. FIG.
Shows an example in which such a rotation detecting device is applied to a steering sensor of an automobile.

A disc-shaped rotating body 1 is mounted in a penetrating state on a steering shaft 2 which supports a steering wheel (not shown), and rotates together with the steering wheel. On the upper surface of the rotating body 1, a thin film annular resistor 3 is provided so as to be concentric with the rotation center of the steering shaft 2. The resistor 3 is in a state in which a part of the resistor 3 along the circumferential direction is cut out, and an electrode 4 is provided at one end 3a thereof. The slider 5 is attached to a fixing member on the vehicle side, for example, a lever combination switch side (not shown), and is provided with its tip end in contact with the resistor 3.

In the above structure, when the steering wheel rotates, the rotating body 1 rotates integrally with the steering shaft 2 accordingly. As a result, the contact position between the resistor 3 and the slider 5 moves to a position corresponding to the rotation angle of the rotor 1, so that the resistance value between the slider 5 and the electrode 4 becomes As shown in FIG. 7, it changes linearly. And by detecting this resistance value,
The value corresponding to the rotation angle of the steering wheel can be electrically detected, and the rotation of the steering wheel can be detected.

By the way, in the above-mentioned configuration, since the absolute value of the resistance value and the rotation angle are detected in association with each other, the linearity of the characteristic of change of the resistance value with respect to the magnitude of the rotation angle and the absolute value of the resistance value. If there is variation in the value, it will result in variation in the detected value of the rotation angle, and the detection accuracy will decrease. However, in general, since the resistor 3 is formed of a thin film, it is difficult to form the resistance value with high accuracy, and it is necessary to consider a manufacturing variation to some extent. It will depend on manufacturing variations. Therefore, in order to improve the detection accuracy even with such manufacturing variations, for example, the following can be considered.

That is, the characteristic of the resistance value of the resistor 3 is measured and stored in advance corresponding to the rotation angle, and the data corresponding to the measured resistance value is compared with the stored resistance value data. Then, the rotation angles of the matching values are read out and corresponded. This makes it possible to improve the detection accuracy of the rotation angle even if the resistance value characteristic of the resistor 3 varies.

However, in the above-mentioned case, an expensive processing circuit such as a means for storing data of resistance value and a microcomputer for performing signal processing is required, so that an inexpensive variable resistor type detecting means is provided. There is a problem that the advantage of using is greatly impaired.

Further, in order to take out the resistance value applied to the resistor 3, it is necessary to make a part of the resistor 3 cut out as described above, and that part becomes a so-called dead zone. Every time the rotating body 1 makes one rotation, the rotation cannot be detected at that portion (in FIG. 7,
(Refer to the area shown in (a)).

Therefore, as a rotation detecting device that solves the above problems, there is a device that detects the rotation angle of a rotating body by light detection or magnetic detection. As an example of this kind of rotation detecting device, for example, a rotation detecting device utilizing light detection is one in which a large number of slits are formed at predetermined intervals along the circumferential direction on the outer peripheral portion of a disk-shaped rotating body, and the slit portion is formed. There is a structure in which a light projecting element and a light receiving element are provided with a light emitting element interposed therebetween.

According to this, since the slit crosses the optical axis of the light projecting element as the rotator rotates, by counting the number of light receiving pulses obtained by the light passing through the slit, the rotation is performed. The rotation angle of the body can be detected.

However, since only the relative value of the rotation angle in any direction can be obtained only with this configuration, in order to detect the rotation direction or the absolute angle, the plurality of slits are displaced. For example, it is necessary to provide a configuration to obtain a plurality of received light pulses, and further, it is necessary to provide a detection circuit for detecting the rotation direction and the absolute angle based on the detected received light pulses. Therefore,
There is a problem that the circuit configuration becomes complicated as a whole and the apparatus as a whole becomes expensive.

The present invention has been made in view of the above circumstances, and an object thereof is a rotation detection device capable of accurately detecting a rotation angle and a rotation direction of a rotating body while having an inexpensive structure. To provide.

[0013]

A rotation detecting device of the present invention includes a rotating body, a base electrode provided on the rotating body, and
A circle having a plurality of resistor films arranged on the base electrode at predetermined angular ranges along the circumferential direction of the circumference corresponding to the concentric position with the rotating body, and adjacent ones having different resistance values set. An annular rotation detecting resistor portion is provided so as to be able to detect a signal corresponding to the resistance value of a resistor film which is provided so as to slide on the rotation detecting resistor portion as the rotating body rotates and which is in contact therewith. It is characterized in that it is provided with a slider.

According to the rotation detecting device having the above-described structure, the rotation detecting resistor portion also rotates together with the rotation of the rotating body, corresponding to the resistance value of the resistor film with which the slider is in contact. The signal is output. At this time, since the adjacent resistance films are set to different resistance values, the detected signal is output while being changed stepwise according to the resistance value. Therefore, the rotation angle of the rotating body can be detected by counting the number of times the resistance value has changed over the entire circumference of the rotating body.

Further, by arranging the rotation detecting resistor portions so that at least three continuous resistor films have different resistance values, the amount of change in the resistance value can be made different in the rotating direction of the rotating body. Therefore, by this, the rotation direction of the rotating body can also be detected based on one detection signal.

Further, by providing the rotation detecting resistor portion with one resistor film having a resistance value different from that of the other resistor film, the resistance value of the resistor film is changed to that of the rotating member. Since it can be set so as to correspond to the reference position as the resistance value detected only once every one rotation of
Thereby, the absolute angle of the rotating body can also be detected.

In this case, since the detection signal is an electric signal generated based on the resistance value of the resistor film, for example, a detection circuit configured to detect rotation based on a light receiving pulse is
The detection circuit can be simple, and the entire apparatus can be inexpensive.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the rotation detecting device of the present invention is applied to a steering sensor of an automobile will be described below with reference to FIGS. In FIG. 1 showing the external appearance of the overall configuration, the disk-shaped rotating body 11 is
It is attached to the steering shaft 12 in a penetrating state and is provided so as to rotate integrally with a steering wheel (not shown). As shown in FIG. 2, a base electrode 13 is provided in an annular shape on the rotating body 11 by printing or etching, for example, along a circumference corresponding to a position concentric with the rotating body 11.

Further, as shown in FIG. 3, the rotation detecting resistor portion 14 arranged in an annular shape on the base electrode 13.
Are provided by printing. This rotation detection resistor unit 14
Are six types of resistor films 15 to 20 having a predetermined film thickness.
However, in a predetermined angular range along the circumferential direction, the entire circumference is arranged in a predetermined order, which will be described later.

Each of the resistor films 15 to 20 is unique so that the resistance value in the film thickness direction is different from the others. The resistor film 15 has a resistance value A, and the resistor film 16 has a resistance value. Value B, resistance film 17 has resistance value C, resistance film 18 has resistance value D, resistance film 19 has resistance value E, and resistance film 20 has resistance value F.
Is set to The magnitude relationship between the resistance values is A
>B>C>D>E> F, and especially the resistor film 2
The resistance value F of 0 is the resistance value A of the other resistor films 15-19.
It is set to be extremely smaller than E.

Of the six types of resistor films 15 to 20, the four types of resistor films 15 to 18 follow the direction of arrow P in FIG. 1 when the resistor film 15 is used as a reference position.
The resistor film 15, the resistor film 16, the resistor film 18, and the resistor film 17 are arranged in the order (the order of the resistance values A, B, D, and C) as one array pattern, and a plurality of these array patterns are configured. Are arranged in.

On the other hand, the other two types of resistor films 19 and 20
Among them, the resistor film 20 is for indicating the reference position which is the neutral position at the rotation position of the steering wheel, and together with the resistor film 19, one of the above-mentioned plurality of arrangement patterns is arranged. Only in the arrangement pattern, the resistor films 20 and 19 are arranged in this order between the resistor films 18 and 17 in the arrow P direction.

Therefore, in the rotation detecting resistor portion 14, all the resistor films 15 to 20 are resistors adjacent to both sides of the reference resistor film when one of them is used as a reference. The body membranes are arranged so that the resistance values thereof are different. In FIG. 1, the resistor films 15 to 20
For the sake of convenience, they are indicated by no mark, the density of diagonal lines, and the filling.

On the rotation detecting resistor portion 14, a fixed member on the vehicle side, for example, a conductor slider 21 attached to a lever combination switch side (not shown) is in contact with the upper surface of the rotation detecting resistor portion 14. It is provided in. The resistor films 15 to 20 are rotated while being in contact with the slider 21 as the rotating body 11 is rotated. Note that FIG. 4 schematically shows the electrical configuration of the rotation detecting device of the present invention, in which the slider 21 of the resistor films 15 to 20 corresponds to the rotation of the rotation detecting resistor portion 14. It is shown that the resistive film in contact changes sequentially.

A detection circuit (not shown) is connected to the slider 21 and the base electrode 13, and this detection circuit is arranged in the film thickness direction of the resistor films 15 to 20 with which the slider 21 is in contact. The resistance value is detected and a signal corresponding to the resistance value is output.

The operation of the above structure will be described with reference to FIG. Now, the rotation detection device is shown in Fig. 1.
When the slider 21 and the base electrode 13 are energized in the state shown in Fig. 1, the detection circuit detects the resistance value of the resistor film in contact with the slider 21 (the resistance value of the resistor film 15 in Fig. 1). A) is detected and a signal corresponding to the resistance value is output as a detection signal.

From this state, when the rotating body 11 rotates together with the steering shaft 2 in the opposite arrow P direction as the steering wheel rotates, the rotation detecting resistor portion 1
4, that is, the resistor films 15 to 20 also rotate integrally. At this time, the rotation detection resistor unit 14 is configured so that the resistor films 15, 16, 1
In the order of 8, 20, 19, 17, 15, ..., The slider 21 is rotated while being in contact with the slider 21, and accordingly, the detection circuit has resistance values A, B, D, F, and E,
, Are sequentially detected, and detection signals corresponding to these resistance values are output.

At this time, as described above, each resistor film 1
Since the resistance values A to F of 5 to 20 are set to different resistance values, the detection signal output from the detection circuit changes in stages and is output as shown in FIG. In particular, as described above, the resistance value F of the resistor film 20 is set to be extremely smaller than the resistance values A to E of the other resistor films 15 to 19, so that the slider 21 becomes the resistor. When in contact with the membrane 20, the detection signal is output at the lowest level.

According to this embodiment, the base electrode 1
3, the rotation detecting resistor portion 14 is formed in an annular shape by the resistor films 15 to 20 having different resistance values, and the resistor contacting the slider 21 by the detecting circuit. Since the detection signal corresponding to the resistance value of the film is output, when the rotating body 11 rotates, the detection circuit detects the resistance value of the resistor film with which the slider 21 is in contact. The signal is output after being changed stepwise. Therefore, by counting the number of times the detection signal has changed, it is possible to detect the rotation angle of the rotating body 11 and thus the steering wheel.

When one of the resistor films 15 to 20 is used as a reference position, the resistor films adjacent to both sides of the reference resistor film have different resistance values. Since the arrangement is made such that the amount of change in the resistance value varies depending on the rotation direction of the rotating body 11, the rotation direction of the steering wheel can also be detected based on one detection signal.

Further, since the resistance film 20 of the resistance films 15 to 20 is provided only at one position corresponding to the reference position which is the neutral position of the steering wheel, the resistance value F thereof is detected. By doing so, the absolute angle of the steering wheel can also be detected using that as the reference position.

In this case, since the resistor film is used to obtain the detection signal that changes stepwise, the detection circuit is simpler than the detection circuit configured to detect the rotation based on the light receiving pulse, for example. Therefore, the entire apparatus can be made inexpensive.

The present invention is not limited to the above embodiments, but can be modified or expanded as follows. The rotation detection resistor unit 14 is composed of six types of resistor films 15 to 20 set to different resistance values, but if there are at least three types of resistor films set to different resistance values, one detection signal is obtained. The rotation direction and the rotation angle of the rotating body can be detected by the output of, and in addition, only one resistor in the rotation detecting resistor unit 14 has a resistance value different from those of these three types of resistor films. With the membrane, the absolute angle can be detected.

The base electrode 13 may be any of copper foil or silver-based conductor as long as it can form a film-shaped conductor. Furthermore, the resolution of rotation detection can be improved by setting a small predetermined angle for each of the resistor films 15 to 20 along the circumferential direction. The present invention can also be applied to rotation detection of a rotating body other than the steering wheel.

[0035]

As is apparent from the above description, according to the first aspect of the invention, the rotation detecting resistor portion is formed by a plurality of resistor films in which adjacent ones have different resistance values. It is configured to be annular, and further, since the signal corresponding to the resistance value of the resistor film in contact with the slider is detected, when the rotating body rotates, depending on the resistance value of the resistor, The signal is output after being changed stepwise. Therefore, the rotation angle of the rotating body can be detected by counting the number of times the signal changes. In this case, since the resistor film is used to obtain the signal that changes in a stepwise manner, the detection circuit can be simplified and the entire device can be inexpensive.

According to the second aspect of the present invention, since the rotation detecting resistor section is configured such that at least three consecutive resistor films have different resistance values, the amount of change in the signal in the rotating direction of the rotor is set. Are different from each other, whereby the rotation direction of the rotating body can be detected based on one detection signal.

According to the third aspect of the present invention, the rotation detecting resistor portion is provided with one resistor film having a resistance value different from that of the other resistor film. The resistance value of the film can be set so as to correspond to the reference position of the rotating body, whereby the absolute angle of the rotating body can be detected.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view in which a base electrode is provided on a rotating body.

[Fig. 3] Side view

FIG. 4 is a schematic diagram of an electrical configuration.

FIG. 5 is a diagram showing a change in resistance value with respect to a rotation amount.

FIG. 6 is a diagram corresponding to FIG. 1 showing a conventional example.

FIG. 7 is a diagram corresponding to FIG. 5;

[Explanation of symbols]

In the drawing, 11 is a rotating body, 13 is a base electrode, 14 is a rotation detecting resistor portion, 15 is a resistor film, 16 is a resistor film, 17 is a resistor film, 18 is a resistor film, 19 is a resistor film, Reference numeral 20 is a resistor film, and 21 is a slider.

Claims (3)

[Claims] 1. A rotating body, a base electrode provided on the rotating body, and arranged on the base electrode in predetermined angular ranges along a circumferential direction of a circle corresponding to a position concentric with the rotating body. An annular rotation detecting resistor portion having a plurality of resistor films each having a resistance value different from each other, and sliding on the rotation detecting resistor portion as the rotating body rotates. A rotation detecting device, comprising: a slider provided so as to detect a signal corresponding to a resistance value of a provided resistor film. 2. The rotation detecting device according to claim 1, wherein the rotation detecting resistor sections are set and arranged so that at least three consecutive resistor films have different resistance values. 3. The rotation detecting resistor unit according to claim 1, wherein the rotation detecting resistor unit includes one resistor film having a resistance value different from that of another resistor film. Detection device.