JPH03221867A - Device for detecting rotation - Google Patents

Abstract

PURPOSE:To prevent the generation of the indicator swinging of a gauge or the flicker of a display and to accurately display an image by setting up the constant rotational speed of a constant rotor so that the relative rotational frequency of the rotor always exceed a fixed value. CONSTITUTION:When a wheel 1 is rotated, its rotation is detected by a rotation detector A, a pulse signal (a) with a period proportional to the rotation is converted into a voltage (b) by an F/V converter 5 and the voltage (b) is outputted to an A/D converter 6. When the constant rotation speed of the con stant rotor 3 is set up so that the relative rotational frequency always exceeds the fixed rotational frequency, the output voltage value (b) from the F/V con verter 5 is made to prevent from becoming a ripple wave having a large voltage variation. A digital output signal (c) corresponding to the voltage value (b) is outputted from the A/D converter 6 to a ROM 7, set points d1, d2 correspond ing to the signal (c) are outputted from the ROM 7 to coils 10a, 10b through D/A converters 8a, 8b and amplifiers 9a, 9b and a movable magnet 11 is rotated to rotate the indicator of a speedmeter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotation detection device that outputs a signal to a vehicle speedometer, engine revolution meter, or the like.

[Conventional technology]

For example, when detecting the speed of a vehicle, a rotation detection device is generally used as the detection means, and the overall configuration is as follows.

A rotation detection device is connected to the wheels of a vehicle, and a pulse signal with a period (frequency) proportional to the number of rotations of the wheels is output to an F/V converter.

This pulse signal is converted into a voltage value by an F/V converter and output to an A/D converter.

A digital signal is output from the A/D converter to the ROM, and the ROM setting value corresponding to this digital signal is amplified via the D/A converter to the coil that controls the rotation of the speedometer's movable magnet, and then output. The movable magnet moves and the speedometer pointer rotates.

Conventionally, a rotation detection device arranged in this manner has a rotating body such as a rotating magnet that rotates in accordance with the rotation of the engine in the case of a wheel or engine tachometer, and a rotating body such as a rotating magnet that rotates in accordance with the rotation of the engine, as shown in Fig. 8. This configuration includes a detection body such as a reed switch that detects rotation and outputs a pulse signal with a period corresponding to the rotation speed in proximity to the rotating body.

That is, a detection body such as a reed switch is fixed to the rotating body to detect the rotational speed of the rotating body.

Furthermore, as shown in Japanese Utility Model Publication No. 62-37126, various types have been proposed, such as one that uses an optical sensor instead of a reed switch as the detection body, but all of them still use a detection body whose rotation is fixed. It is detected by

=3 [Problem to be Solved by the Invention] Therefore, the conventional rotation detection device has a configuration in which the detection body is fixed and the rotation of the rotating body that rotates with respect to the detection body is detected. The frequency of the pulse signal output to the V converter is O when the vehicle is stationary and the wheels are not rotating, as shown in Figure 4, and increases sequentially from frequency 0 as the rotation increases. .

However, in the low frequency range between 0 and α, the output voltage output from the F/V converter is as shown in the lower part of Fig. 5 even if the output pulse signal from the rotation detection device is constant. This results in a ripple wave with large voltage fluctuations, and the digital output signal of the A/D converter that outputs this ripple wave becomes unstable, and accordingly, unstable data is also output from the ROM.

Therefore, when the frequency of the pulse signal is in a low frequency region, that is, in a region where ripple waves are likely to occur, there is a problem that the pointer of the speedometer swings up and down, resulting in unstable indications and inability to give accurate indications.

Further, a similar problem occurs when the rotation detecting device is applied to an electronic speedometer.

For example, as disclosed in Japanese Patent Application Laid-Open No. 64-89818, when counting pulse signals output from a rotation detection device using the Zumbling method, the pulse signals have a particularly low frequency (or a duty ratio). low), the count values may differ even though the sampling time is the same.

This causes the displayed value to flicker.

In addition, even if the method of measuring the time of one cycle of the pulse signal (7) is applied to display the measured value in correspondence with new display data, the pulse signal has a low frequency, that is, the time of one cycle. As the time period becomes longer, the time it takes to switch the display becomes longer, resulting in a problem that the device has a slow response speed.

The present invention provides a rotation detection device that solves these drawbacks.

[Means to solve the problem]

The present invention will now be described in detail with reference to the accompanying drawings.

Responds to changes in objects to be measured such as wheels and engines.

A rotating body 2 that rotates at a constant speed, a constant speed rotating body 3 that rotates at a constant speed in the same direction or in the opposite direction around a concentric circle -L of this rotating body 2, and a detection object installed on the rotating body 2 or the constant speed rotating body 3. 4
A rotation detection device A, which outputs an output signal a corresponding to a change in the object to be measured due to a change in the object to be measured, such as a magnetic or electrical change, without the rotation body 2 or the constant speed rotation object 3 reaching the detection object 2. Therefore, the constant rotation speed of the constant speed rotating body 3 is
The present invention relates to a rotation detecting device characterized in that the relative rotational speed with respect to the rotating body 2 is always set to be equal to or higher than a certain value.

a signal output device that outputs a signal every time an object to be measured such as a wheel or an engine changes by a certain amount; a constant signal output device that outputs a signal at fixed time intervals; and a signal amount output by the constant signal output device and the A calculation is performed to add or subtract the amount of signal output from the constant signal output device, and this calculated value is used to respond to changes in the object to be measured.1. and an arithmetic unit that outputs a calculated output signal a, the output signal of the constant signal output device being set so that the calculated value is always equal to or higher than a predetermined value. This is related.

[For production]

Since the constant speed rotating body 3 always rotates at a constant speed,
Even if wheel 1 is not rotating, the relative rotation speed is 0.
Since this is not the case, the frequency of the output signal a will not be O. That is, by setting the constant rotational speed of the constant-speed rotary body 3 so that the relative rotational speed is always higher than the fixed rotational speed, the output voltage from the F/V converter is different from ripple waves with large voltage fluctuations. You can set it so that it does not occur.

Also, in the electronic rotation detection device A, its output signal A
can be set so that it does not become a low frequency or low duty ratio signal.

〔Example〕

When this embodiment is applied to a speedometer, for example, the first
FIG. 2 illustrates a first embodiment thereof.

First, a rough groove bottom will be explained based on FIG. 1.

A rotation detection device A is connected to the wheel 1, and this rotation detection device A
Connect the F/V converter 5 to the F/V converter 5, and connect the A/V converter 5 to the
D converter 6, ROM 7, D/A converters 8a and 8b1 amplifiers 9a and 9b, and a movable magnet 1 that moves the needle of the speedometer.
The coils 10a to 10b controlling the coils 1 are connected in sequence.

When the vehicle moves and the wheel 1 rotates, this rotation is detected by the rotation detection device A, and a pulse signal a having a period (frequency) proportional to this rotation is output to the F/V converter 5.

When this pulse signal a is converted into a voltage value S by the F/V converter 5 and outputted to the A/D converter 6, a digital output signal corresponding to the voltage value 1] is output from the A/D converter 6. C is output to the ROM 7, and the setting value d+'d2 of the ROM 7 corresponding to this digital output signal C is applied to the movable magnet ti of the speedometer via the D/A converter 8a, 81) and the amplifiers 9a, 9b. Coil 10a- for controlling rotation
10b, the movable magnet 11 rotates, and the pointer of the speedometer is supported.

FIG. 2 is a schematic diagram of the rotation detection device A.

The rotation detection device A includes a rotating body 2 that rotates according to the rotation speed of the wheels 1 and the engine, and a constant-speed rotating body 3 that rotates at a constant speed.
and a detection body 4 installed on the constant speed rotary body 3 that detects the relative rotational speed between the rotary body 2 and the constant speed rotary body 3 and outputs a pulse signal a.

The rotating body 2 is a disc-shaped magnet, and has a plurality of S poles and N poles.
The poles are magnetized so that they are adjacent to each other.

In addition, a donut-shaped constant speed rotating body 3 whose center of rotation is the same as that of this rotating body 2 is installed in a concentric circle of this rotating body 2, and a rotating body is installed in a part of this constant speed rotating body 3. Detector 4 such as a reed switch that turns 0N-OFF due to changes in the magnetic field of 2
will be established.

Next, the operation will be explained.

First, a case will be described based on FIG. 6 in which a rotation detection device A in which the constant speed rotating body 3 rotates in the same direction as the rotational direction of the rotating body 2 is used.

When the vehicle is stationary, the wheels 1 rotate 1. Since there is no,
The rotating body 2, which rotates accordingly, also remains stopped.

However, since the constant speed rotating body 3 always rotates around the rotating body 2 at a constant speed, the detection body 4 of the constant speed rotating body 3 detects changes in the magnetic field of the rotating body 2 that is stationary (7). A pulse signal a of frequency β is output.

Next, when the vehicle starts running from the stopped state, the rotating body 2
starts rotating so as to follow the constant speed rotating body 3 which is rotating at a constant speed. Since the rotation of the rotating body 2 corresponds to the rotation of the wheel 1, as the speed of the wheel increases, the relative rotational speed between the rotating body 2 and the constant speed rotating body 3 gradually decreases, and the pulse becomes a downward-sloping frequency. Outputs signal a. This is the relative rotational speed at which the pulse signal a of frequency α is output when the vehicle reaches its maximum speed.

That is, if the constant rotational speed of the constant-speed rotating body 3 is set differently in this way, the frequency of the pulse signal a will gradually decrease as the rotation of the wheel l becomes faster, but at the maximum rotation when the wheel l rotates at the maximum speed, Even if there is, the coarse rotational speed, that is, the frequency of the pulse signal a, will not become lower than the upper limit frequency α of the ripple generation region as in the case of two series.

Therefore, the F/V converter 3 to which this pulse signal a is output
It is possible to prevent the voltage fluctuation of the output voltage value from becoming large and prevent the meter needle from shaking.

Further, a rotation detection device A in which the constant speed rotating body 3 rotates in a direction opposite to the rotational direction of the rotating body 2 that rotates according to the rotation speed of the wheel 1.
As shown in FIG. 7, even when the vehicle is stopped and the wheels 1 are not rotating, the constant speed rotating body 3 is at a constant speed relative to the stationary rotating body 2. The rotation detecting device A outputs a pulse signal a having a frequency α. If the rotation of the wheel 1 increases, the relative rotational speed between the rotary body 2 and the constant speed rotary body 3 will further increase, so that a pulse signal a having a frequency diagonal to the right is output.

However, if the constant rotational speed of the constant-speed rotating body 3 is set in this way, the frequency of the pulse signal a will not become lower than the second limit frequency α of the ripple generation region.

Therefore, effects similar to those described above can be obtained.

In this way, it is possible to set the frequency of the pulse signal a so that it does not fall below α, which is the ripple generation region.

That is, a high frequency pulse signal a is always output, and F/
The V converter 5 can always output a stable signal with small voltage fluctuations as shown in the upper part of FIG.

In addition, in Fig. 2, a disk-shaped rotating magnet is connected to a constant-speed rotating body 3.
Even if a rotary disk equipped with a donut-shaped detecting body 4 surrounding it is constructed as the rotating body 2, the detecting body 4, which rotates in response to the rotation of the city axis l, will not rotate at a constant speed with the rotating body 2. In order to detect the relative rotation speed with the body 3 in the same way, the action (-
1 has the same effect.

In addition to the above-mentioned embodiments, the following devices may also be considered.

That is, a signal output device that converts wheel rotation into a pulse signal, a constant signal output device that outputs a pulse signal at fixed time intervals, a counter that counts each pulse signal, and adds or subtracts each count value. It is equipped with an arithmetic unit, and outputs the calculated value processed by the arithmetic unit as an output signal a. At this time, the signal output unit is connected to the rotating body 2 of the above embodiment.
The constant signal output device corresponds to the constant speed rotating body 3.

When outputting a frequency similar to that shown in Fig. 6, the number of pulse signal outputs of the constant signal output device is set high, and the count value of the signal output device, which increases as the rotation of the wheel becomes faster, is controlled by a calculator. It is sufficient to subtract it from the count value of the constant signal output device, and even in the case of Fig. 7, it is sufficient to add the count value of the signal output device to the count value of the constant signal output device; in any case, the calculated value is It is sufficient if it is below a certain value.

In addition, as shown in FIG. 3, a reed switch 4a is used as the detection object 4.
Instead, the one-type optical sensor described above or another detection method as shown in Japanese Utility Model Publication No. 60-35897 shown in FIG. 3 may be adopted as appropriate.

Furthermore, the means for transmitting rotation from the wheels 1 to the rotating body 2 and the means for driving the constant speed rotating body 3 can be designed as appropriate.

〔Effect of the invention〕

In the present invention, the detecting body is not fixed, but is provided on a rotating body or a constant speed rotating body, and the detecting body responds to changes in the measured object by magnetic or electrical changes exerted by the rotating body or constant speed rotating body. The configuration is configured to output an output signal, and the rotational speed of the constant-speed rotating body is set appropriately in advance so that the relative rotational speed with the rotating body is always a constant rotational speed. It is possible to provide an extremely practical rotation detection device that can output a high-frequency output signal, thereby providing an instrument that does not cause any wavering of the pointer, flickering of the display, or reduction in reaction speed. Become. In addition, the signal output device that outputs a signal every time the object to be measured changes by a certain amount does not directly output the signal, and the signal amount output by the constant signal output device and the signal amount output by the constant signal output device are The configuration is configured to perform an operation of addition or subtraction, and output this calculated value as an output signal corresponding to a change in the object to be measured. Since we have set the output signal of the device, we can always output a high frequency output signal above a certain level, as mentioned above.
Therefore, it is possible to provide an extremely practical rotation detection device that does not cause any shaking of the pointer, flickering of the display, or reduction in reaction speed.

[Brief explanation of drawings]

Fig. 1 is a block diagram when this embodiment is used in a speedometer, Fig. 2 is a schematic explanatory diagram of the main parts of this embodiment, and Fig. 3 is a schematic explanation of the main parts of this embodiment when it is tilted sideways. Figure 4 is a characteristic graph of the frequency of the pulse signal output to the F/V converter with respect to the rotational speed of the conventional wheel. Figure 5 shows the case where a high frequency pulse signal is input and the low frequency pulse signal. Graphs showing the output voltage values output from the P/V converter shown on the second side and the bottom side are for the case where a ripple wave is generated when the rotating body and the constant speed rotating body are in the same direction. Figure 7 shows the characteristic graph of the frequency of the pulse signal output to the F/V converter with respect to the rotational speed of the wheel when the rotating body rotates at a constant speed. FIG. 8 is a schematic explanatory diagram of the main part of the conventional example. a Output signal, A...Rotation detection device, 1...Wheel, 2
...Rotating body, 3... Constant speed rotating body, 4 Detection object. January 1990

Claims (1)

[Claims] 1. A rotating body that rotates in response to changes in an object to be measured, such as a wheel or engine, and a constant-speed rotating body that rotates at a constant speed in the same or opposite direction on a concentric circle of this rotating body. , a rotating body or a detecting body installed on a constant-speed rotating body, and an output that corresponds to changes in the object to be measured due to magnetic, electrical, etc. changes exerted on the detecting body by the rotating body or constant-speed rotating body. 1. A rotation detection device that outputs a signal, characterized in that the constant rotation speed of the constant speed rotating body is set so that the relative rotation speed with respect to the rotating body is always above a certain level. 2. A signal output device that outputs a signal every time an object to be measured such as a wheel or an engine changes by a certain amount, a constant signal output device that outputs a signal at fixed time intervals, and a signal amount that the constant signal output device outputs. and an arithmetic unit that performs an operation of adding or subtracting the amount of signal outputted by the constant signal output device, and outputs the calculated value as an output signal corresponding to a change in the object to be measured. A rotation detection device characterized in that the output signal of the constant signal output device is set so that the calculated value is always greater than or equal to a predetermined value.