JPH01126506A - Indicator display mechanism for electric dial gauge - Google Patents

Abstract

PURPOSE:To improve the control method of a high speed indicator driving apparatus having high resolving power, by obtaining the apparatus by combining a small two-pole stepping motor rotatable reversibly with a gear group. CONSTITUTION:A gear 11 having an indicator 3 mounted to the shaft thereof is meshed with a transmission gear 12 while the gear 12 is mounted to the shaft of the rotor 14 of a two-pole stepping motor 13. Therefore, when an one step drive signal is inputted to the motor 13, the rotor 14 rotates by half to rotate the gear 11 through the gear 12 and the indicator 3 moves in proportion to the number of teeth of the gears 11, 12. The signal from an encoder 31 and that from an indicator position counter 25 are inputted to a comparing circuit 22 in a control circuit block 20 and, when there is difference between these inputs, forward and reverse rotations are discriminated by a forward and reverse rotation discrimination circuit 23. A drive signal is generated corresponding to the discrimination result by a drive signal generating circuit 24 to be outputted to the stepping motor 13 and the indicator 3 is moved by one step by said signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pointer display device for a dial gauge that measures a dimension, quantizes it (encoder), and displays the measured value.

[Summary of the invention]

The present invention digitally processes the signal from the encoder, displays it as a numerical value, moves a mechanical pointer for the smallest digit, and finally displays the analog signal. The pointer positions are compared and the pointer is driven according to the control circuit.

[Problems with conventional technology]

Conventional electric dial gauges with encoders use digital numeric displays using liquid crystals or light emitting diodes. In addition to this, it is also practical to provide an analog display with a display consisting of multiple arrays of elements such as liquid crystals or light emitting diodes, and increase or decrease the number of blinks according to the measured value. has been made into

Another method for analog display is to use the mechanism of a conventional mechanical dial gauge as is, incorporate an encoder linked to the detection part, and send the output signal from the encoder to an external peripheral device. Some devices equipped with a signal processing section for this purpose have also been put into practical use.

However, the former method has the disadvantage that it is difficult to quantitatively understand the measured values because of the digital display using numbers. In addition, it is necessary to solve this problem (even in the case of an analog display in which multiple light emitting elements are arranged, it is possible to know whether the measured value is high or low, but the measured value It is not suitable for quantitatively understanding the magnitude of the difference.

In the latter case, it is easier to use in that it uses the pointer display of the conventional mechanical dial gauge, which is most suitable for these demands for analog display, but it does not have a mechanical detection section inside. However, because the encoder has two detection systems, it is difficult to correlate them, and since there are two mechanisms in one dial gauge at the same time, an increase in cost is unavoidable.

[Problem that the invention seeks to solve]

As mentioned above, various attempts have been made to display the digital signal from the encoder in analog form, but no attempt has been made to use this digital signal to directly move a mechanical pointer. The reasons for this are: 1) The pointer must be rotated at high speed, forward and backward.

2) One rotation of the pointer requires at least 100 graduations, which requires high resolution and high angular accuracy.

3) It is required to be small in order to be accommodated in a dial gauge.

4) Low power consumption is required.

etc.

In the case of a mechanical dial gauge, the detection cylinder is
It operates at a maximum speed of several meters and seven seconds, and the pointer rotates to follow this speed. On the other hand, if you want to move this pointer electrically, you must use a motor or actuator, but in order to increase the resolution of the display, you must use one with a large number of steps. In that case, it is difficult to increase the speed, and it is difficult to make it operate exactly the same as a conventional mechanical type. Therefore, we reduced the rotational speed of the pointer to a level at which the response speed would not be perceived as unnatural by the user, and eliminated unnecessary movement of the pointer until the detection cylinder reaches the object to be measured. , it is possible to realize an electric dial gauge that can display the pointer at a speed that does not pose a problem for practical use.

That is, an object of the present invention is to obtain a high-speed, high-resolution pointer driving device, devise a control method thereof, and obtain an improved control circuit.

[Means for solving problems]

In the present invention, by combining a small two-pole stepping motor capable of forward and reverse rotation with a gear group,
It is possible to inscribe an indicated angle of 100 steps or more in one revolution of the pointer, and the angle accuracy is maintained at a high value. However, with only this drive device, if only 1
Even if the pointer is rotated at a speed of 00 steps/second, the
It takes one second to rotate, making it unsuitable for practical use. However, among the movements of conventional mechanical dial gauges, the pointer moves at the highest speed when moving the detection cylinder to the object to be measured. do not have.

Also, as long as the device is for humans to read measured values, there is no need to increase the reading speed beyond that. Therefore, we have combined a control circuit that avoids moving the pointer in response to all the movements of the detection cylinder, and controls the pointer to move the shortest distance after the detection cylinder hits the object to be measured. , when used by humans,
I was able to make movements that didn't feel slow.

〔Example〕

FIG. 1 shows an embodiment embodying the present invention, and shows an external view of an electric dial gauge. In this embodiment, only the minimum digit of the measurement condition of this dial gauge is displayed with a pointer. The above digits show an example in which a display element such as a liquid crystal is used to display digital values.

Here, the display section of the dial gauge main body 1 includes a scale plate 2, a pointer 3. A liquid crystal display 4 for digital display is disposed thereon, and a detection cylinder 5 is attached to the outside of the main body 1. The display of measured values on this dial gauge is exactly the same as that of a conventional mechanical type; the pointer moves left and right on the scale plate 2 and the value where the pointer and the scale match is read.

FIG. 2 shows a driving device for rotating the pointer 3. The pointer 3 is attached to the shaft of the gear 11. This gear 11 meshes with a transmission gear 12, and the transmission gear 12 is attached to the shaft of a rotor 14 of a stepping motor 13.

As the stepping motor 13, a two-pole stepping motor was used. Therefore, this stepping motor 1
When a 1-step drive signal is input to 3, the rotor 14
rotates half a rotation, which rotates the gear 11 via the transmission gear 12, so the pointer 3 moves by an amount proportional to the ratio of the number of teeth of the gear 11 and the transmission gear 12.

Therefore, the number of steps in one revolution of the pointer 3 or the angle per step can be determined by adjusting the number of teeth of the gear 11 and the transmission gear 12. In addition, the indicating angle accuracy of each step is also determined by the manufacturing accuracy of the gear 11 and the transmission gear 12. In particular, if the gear 11 has a number of teeth close to the number of steps of the pointer, the indicating angle accuracy will be close to the manufacturing accuracy of the gear 11. It is easy to obtain high accuracy. Further, when the pointer 3 is stationary, by using a permanent magnet in the rotor 14 of the stepping motor 13, static torque can be obtained without applying electric power, so power can be saved.

Next, FIG. 3 shows a block diagram of the control circuit.

In this figure, a digital signal from an encoder 31 is used as an input to the control circuit block 20.

Also, as an output from the control circuit block 20,
It is assumed that a driving signal is sent to the stepping motor 13. The operation of the control circuit block 20 begins with converting a signal sent from the encoder 31 from a binary number to a hexadecimal number in the counting section 21 and sending it to the comparison circuit 22. This comparator circuit 22 receives a signal from a pointer position counter 25 as another input. The comparison circuit 22 compares these two inputs, and if they are the same, outputs nothing,
Return to human power state again. If there is a difference between these two inputs, the difference is sent to the forward/reverse rotation determination circuit 23. The forward/reverse rotation determination circuit 23 calculates the number of steps when the difference between the sent pointer position and the measured value is forward rotation and reverse rotation from the current pointer position, and selects the smaller rotation direction. and sends it to the next drive signal generation circuit 24. At the same time, the forward/reverse rotation discrimination circuit 23 adds plus 1° to the pointer position counter 25 in the case of forward rotation and minus 1 in the case of reverse rotation. The drive signal generation circuit 24 is a forward/reverse rotation discrimination circuit 23
The stepping motor 13 receives a signal from the stepping motor 13 and generates a drive signal for forward or reverse rotation for one step.
Output to. This causes the pointer to move in one step. When this series of operations is completed, the comparator circuit 22 enters the input state again, and repeats a series of judgments and controls regarding the next movement of the hand.

Note that when a battery or the like is inserted as a power source into this electronic dial gauge, the pointer position counter 25 is reset and becomes 0, but the pointer position at that time is not necessarily O. , pointer position counter 25
It is necessary to perform an operation to match the values of . Therefore, in this control circuit block 20, a step circuit 26 is provided. This step circuit 26 moves the pointer 3 from the current position in the plus direction according to the number of times the externally provided plus step hand key 33 and the minus step hand key 34 are pressed, or the amount of time they are pressed. Alternatively, a signal for moving the hands in the negative direction is sent to the drive signal generation circuit 24. This allows the pointer to move to the scale plate 2.
If the pointer position counter 25 is reset by pressing the reset key 35 at this point, the position of the pointer 3 and the value of the pointer position counter 25 will match. This is an initial setting operation, and once the above-mentioned series of measurement operations are started, the difference between the support value and the measured value disappears.

Also, when you finish using this electric dial gauge and turn off the power, back up only this part with a battery or use a non-volatile memory element so that the contents of the pointer position counter 25 are not lost. By doing so, you can omit the initial value setting the next time you use it. Also, by using this initial value setting, it is possible to correct lζ in the case where some kind of large impact is applied to the main body and the position of the pointer shifts.

That is, this control circuit block 20 compares the pointer with the measured value every time the pointer moves one step, and even if the current measured value and the position of the pointer are significantly different, the difference is Since it moves only one step in the direction, if the detector cylinder moves suddenly, it will not follow and the detector cylinder will move slowly, or if it is stationary, the indicated value of the pointer will be different from the measured value. It will converge.

This pointer driving method is effective as an analog display method for fast-moving measured values, and can be applied to other applications as it does not require complex signal processing and can be realized with a very simple circuit. For example, electronic weight scales, electronic calipers, etc. Further, although the control circuit block 20 shown in FIG. 2 shows the configuration as a circuit, it is also possible to replace this with one microprocessor sensor, thereby achieving further miniaturization.

〔Effect of the invention〕

As described above, in the present invention, by providing a high-speed, high-resolution needle drive device and a control circuit, the advantages of the analog display of the conventional mechanical dial gauge can be utilized, and in addition, the advantages of the analog display of the conventional mechanical dial gauge can be utilized. The characteristics of high precision and data versatility can be contained in one compact device.

An electric dial gauge was obtained that can also contribute to cost reduction.

Furthermore, the control method of the present invention does not simply reproduce the operation of conventional mechanical dial gauges, but is designed to be considered from the user's perspective, eliminate unnecessary movements, and be more practical. It is possible and beneficial. This solves the problem of the measurement values of conventional digital measuring instruments being accurate, but making it difficult for the person measuring them to grasp the actual amount. Even in such cases, there are advantages such as being able to quantitatively grasp the progress of cutting and making it easier to understand the relationship with the target value.

[Brief explanation of the drawing]

Fig. 1 is a front view of an electric dial gauge in which the present invention is implemented, Fig. 2 is a perspective view of a drive device for moving the pointer of the dial gauge, and Fig. 3 is a block diagram of its control circuit. . 1...Dial gauge body 2...Scale plate 3...Pointer 4...Liquid crystal display 5...Detector cylinder 11...Gear 12...Transmission gear 13...Stepping motor 14 ... Rotor 20 ... Control circuit block 21 ... Counting section 22 ... Comparison circuit 23 ... Reverse rotation determination circuit 24 ... Drive signal generation circuit 25 ... Pointer position counter 26 ...・Multi-needle circuit 3I...Encoder 32...Display unit 33...Plus multi-needle key 34...Minus multi-needle key 35...Reset key and above A front view of the τ scheme of the present invention Pointer of the present invention, perspective view of drive type 1 Fig. 2

Claims (2)

[Claims] (1) In a dial gauge consisting of an encoder and a mechanical pointer display, there is a drive device for electrically moving the pointer, and a signal from the encoder and the pointer position each time the pointer moves one step. A pointer display mechanism for an electric dial gauge, characterized in that it has a control circuit for comparing the values and sending a driving signal for one step to a driving device. (2) The pointer display mechanism for an electric dial gauge according to claim 1, wherein the drive device comprises a stepping motor and a gear group.