JPH02248708A - Position detector for actuator - Google Patents

Abstract

PURPOSE:To detect plural positions by one position detector by storing substrates in a case, loading plural detecting elements on one main surface of plural substrates and incorporating the detecting elements in such a manner as to be displaced from each other in the moving direction of a moving portion of an actuator. CONSTITUTION:A detector 3 is loaded on one main surface of a substrate 2 and has detecting elements 3a, 3b. The detector is disposed in such a manner as to shift for the distance corresponding to the length of a piston for detecting the stroke end of the piston by the detecting elements. An integrated circuit 4 is electrically connected to the detecting elements 3a, 3b, and the circuit comprises amplifiers 9a, 9b, comparators 10a, 10b, an AND element 11 and output elements 12a, 12b. The output elements 12a, 12b are adapted to conduct logical operation for switching signals C, D from the comparators 10a, 10b and a signal conversion output of a converting element and send output signals F, G. The signals F, G are turned on at both ends of the stroke and sent to light emitting diodes 5a, 5b to display the position of the stroke end.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a position detection device used in an actuator, particularly for an actuator that is capable of detecting the position of a short stroke piston of a fluid pressure actuator such as an air cylinder. The present invention relates to techniques that are effective when applied to position detection devices.

[Conventional technology]

Generally, in a fluid pressure actuator such as an air cylinder, a position detection device equipped with a detection element such as a reed switch or a magnetic resistance element is used to detect the stroke position of a piston.

Efforts have been made to miniaturize this type of position detection device itself, but now that the demand for smaller actuators is increasing, miniaturization of position detection devices has led to miniaturization of actuators. The reality is that we are no longer able to keep up.

In particular, in actuators used in robots, precision automatic equipment, semiconductor manufacturing equipment, etc., the stroke of the piston of the actuator itself has become extremely short.

Therefore, conventionally, in order to detect the piston position in such a short stroke actuator, one position detection device was provided at each stroke end, and these position detection devices were arranged in the piston movement direction and in the direction perpendicular to the piston movement direction. A device in which the device is arranged at a different location is being considered.

[Problem to be solved by the invention]

However, with this technology, in addition to requiring multiple position detection devices, there is also a limit to how small the size of the position detection device can be, resulting in a large position detection device as a whole. Put it away.

In addition, in order to attach multiple position detection devices to an actuator, mounting grooves and mounting tools are required according to the number of position detection devices, which increases the cost of processing these grooves and manufacturing the mounting tools. There are problems such as complicated installation work to the actuator.

Furthermore, in the past, especially in the case of a position detection device with a long operating distance, that is, a long ON time, it was difficult to set the device and required adjustment of the setting. The inventors have also found that there are problems such as difficulty in

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a technique that can detect multiple positions such as both stroke ends using only one position detection device.

Another object of the present invention is to provide a technique that can accurately detect the position of a moving part with an extremely short stroke.

Still another object of the present invention is to provide a position detection device for an actuator that is small and easy to implement.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

That is, the actuator position detection device of the present invention has the following features:
Boards are housed in one case, a plurality of detection elements are mounted on the entire surface of the plurality of boards, and the detection elements are built in and displaced from each other in the movement direction of the moving part of the actuator. be.

Further, the detection element and the substrate are embedded in a case integrally molded with synthetic resin.

Furthermore, the plurality of detection elements are formed in a one-chip detector.

[Effect]

According to the actuator position detection device described above, multiple detection elements are built into one case, so that multiple positions such as both stroke ends can be accurately detected with only one position detection device. No need to adjust settings.

Further, by displacing the positions of a plurality of detection elements within one case by a desired distance, position detection with an ultra-short stroke becomes possible.

Furthermore, by integrally molding the detection element and the substrate with synthetic resin within the case, it is possible to protect the detection element and the substrate in a sealed state.

Further, by forming a plurality of detection elements into a single-chip detector, the detector itself can be made more compact.

〔Example〕

Fig. 1 is a schematic enlarged perspective view of a position detection device for an actuator which is an embodiment of the present invention, Fig. 2 is a perspective view showing a state in which this position detection device is mounted on an air cylinder, and Fig. 3 is a position detection device. The circuit diagram of the device, Figures 4(a) to (6) are the third
FIG. 3 is a waveform diagram showing output signals of each circuit element in the figure.

First, the configuration of the actuator position detection device of this embodiment will be explained with reference to FIG.

The position detection device l of this embodiment includes a substrate 2, a detector 3 mounted on the substrate 2, a dedicated or general-purpose integrated circuit element 4 for processing signals detected by the detector 3, and a display device 4. It is composed of a light emitting diode 5 and a lead wire 6. These substrate 2, detector 3, and integrated circuit element 4 are integrally molded and embedded in a case 7 made of synthetic resin such as epoxy resin.

The detector 3 of this embodiment has two detecting elements 3a and 3b formed of magnetic resistance elements, for example, formed on one chip.For example, the piston of the cylinder 8 as an actuator shown in FIG. Both stroke ends (not shown) are detected by respective detection elements 3a and 3b.

That is, the detector 3 with two built-in detection elements 3a and 3b is mounted on one main surface of the substrate 2, and the rain detection element 3a is mounted on one main surface of the substrate 2.
, 3b are arranged such that they are shifted from each other in the piston movement direction by a distance corresponding to the length of the piston stroke.

In addition, in the case of this embodiment, it is possible to easily cope with the case where the detected stroke is an extremely short stroke.
For this purpose, two detection elements 3a and 3b are each formed on one chip as described above. Furthermore, if it is desired to detect three or more positions, three or more detection elements may be housed within one chip at a desired distance from each other. With such a structure, the detector 3 itself can be made more compact.

Each of the integrated circuit elements 4 is a detection element 3a.

3b through printed wiring (not shown) on the substrate 2, and as shown in FIG.
Amplifiers 9a and 9b that amplify the detection signal from 3b, comparators 10a and 1Ob that compare the amplified signals from amplifiers 9a and 9b with a reference voltage, and logic that performs an AND operation on the switching signals from comparator 10a and job. A product element 11 and a comparator 10a.

Output element 12 that forcibly turns off the switching signal from 10b by the inhibit signal of AND element it.
It consists of a and 12b.

The output elements 12a and 12b are, for example, a conversion element that converts the code of the inhibit signal of the AND element 11, and an AND element that performs an AND operation on the switching signals from the comparators toa and tab and the code conversion output of the conversion element. It consists of etc.

Furthermore, the light emitting diodes 5 are also connected to respective output circuits, and are comprised of light emitting diodes 5a and 5b that display the detection of both stroke ends of the piston.

Although omitted in FIG. 1 for clarity, in order to attach the position detection device 1 to the mounting groove 14 of the cylinder body 13 as shown in FIG. 2, a mounting flange is provided on the side surface of the position detection device 1. A portion 15 is integrally protruded, and the position detection device ff is connected to the cylinder body by a screw 16 at this mounting flange B15! It is attached to 3.

In addition, in addition to the cylinder 8, 17 is a piston rod, 1
8 is a compressed air supply/discharge port, and 19 is a mounting hole.

Next, the operation of this embodiment will be explained.

First, when manufacturing the actuator position detection device 1 of this embodiment, a detector 3 with built-in detection elements 3a and 3b is used.
, the integrated circuit element 4, the light emitting diodes 5a and 5bs, and the leads 116 are mounted on the substrate 2, housed in the case 7, and sealed with resin. In this case, these detectors 3, integrated circuit elements 4, etc. are mounted on one main surface of the substrate 2. As a result, the enclosed detector 3
An actuator position detecting device 1 is obtained in which the actuator 3, integrated circuit element 4, and light emitting diode 5a are built in a single case 7.

5b can be protected in a closed state.

Next, when this actuator position detection device 1 is applied to the cylinder 8 as shown in FIG. 2, its operation will be explained based on FIGS. 3 and 4.

First, the stroke end of a piston (not shown) of the cylinder 8 is detected by the detection element 3a or 3b, respectively. That is, the position detection signal obtained by detecting the approach of a magnet (not shown) provided on the piston of the cylinder 8 by each detection element 3a, 3b is
, -3b are output to amplifiers 9a and 9b, respectively.

The position detection signals amplified by the amplifiers 9a and 9b correspond to the distance between the detection elements 3a and 3b in the piston movement direction, that is, the stroke distance S of the piston, as shown in FIG. The amplified signals A and B are outputted as peaks at the positions of the respective detection elements 3a and 3b.

Furthermore, the amplified signal A from each amplifier 9a, 9b.

B is input manually to comparators 11)a and 10b, and
a ; :H: i, Ob, and j are compared, and it is detected whether the piston of cylinder 2 or cylinder 8 is at the stroke end of either. Pa2. S.1, When this happens, the amplifier 9a is transmitted from the detection elements 3a and 3b.

9b, each of the amplified signals A and B is sent to the comparator 1.
Each detection element 3a, 3b is turned on at the same time by 0a, 1Ob.
A switching signal C is compared with a reference voltage V to ensure a state of
, D.

Then, as shown in FIG. 4(b), a comparator 10a.

Switching signals C and D from 10b are turned on around the position of stroke distance S.

Further, the switching signals C and D from each of the comparators 10a and 10b are input to the AND element 11 and subjected to an AND operation, whereby both the switching signals C and D are output as shown in FIG. 4(C). An inhibit signal E that is turned ON when in the ON state is output.

Furthermore, the switching signal C from the comparators 10a and lOb
, D and the inhibit signal E from the AND element 11 are input to the output elements 12a and 12b, and the switching signal C
, D are forcibly turned off by the inhibit signal E. Then, the output signal F of the output elements 12a and 12b
, G are in the ON state at both ends of the stroke distance S as shown in FIG. 4(d), and the output terminal 0 of the position detection device l
U.T.I.

It is output as a detection signal of each stroke end to 0UT2. Furthermore, depending on this, the light emitting diode 5a or 5b
is emitted, and an operation display for detecting the position of the cylinder 8 at both stroke ends is performed.

As described above, in the position detection device 1 of this embodiment,
By housing the plurality of detection elements 3a, 3b in one case 7, it is possible to accurately detect a plurality of positions such as both stroke ends with only one position detection device 1, and also the plurality of detection elements 3a, By displacing the positions of 3b from each other by a desired distance, position detection of an ultra-short stroke is possible.

As above, the invention made by the present inventor has been specifically explained based on Examples, but it should be noted that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Not even.

For example, with regard to the detector 3 of this embodiment, a case has been described in which a plurality of detection elements 3a and 3b are formed on one chip, but the present invention is not limited to this, and each detection element 3a and 3b may be formed on one chip. , a plurality of detection elements 3a, 3b
They may be mounted in parallel and do not need to be provided on one board 2.

Further, the case 7 in the present invention is not necessarily limited to a molded product of synthetic resin, and may be of other types such as a box shape.

Furthermore, although the position detection device 1 of this embodiment has been described with reference to the case where it is applied to the cylinder 8, the present invention is not limited thereto, and can be widely applied to actuators such as a low actuator.

〔Effect of the invention〕

Among the inventions disclosed in this application, the effects obtained by typical inventions are briefly described below.

(1) A plurality of detection elements are mounted on the entire surface of a board housed in one case, and these detection elements are displaced from each other in the moving direction of the moving part of the actuator. Since the distance between the detection elements can be set appropriately as necessary, it is possible to reliably detect a moving part with a short stroke, and it is particularly applicable to an actuator with an ultra-short stroke.

(2) By embedding the detection element and board in a case integrally molded with synthetic resin, the detection element and board are protected in a sealed state, which improves the lifespan and reliability of the position detection device. It is.

(3) By forming multiple detection elements into a single-chip detector, it is possible to make the detector more compact, and at the same time, it is possible to reduce the position It is possible to downsize the detection device.

(4) The above (1), (2) and (3) simplify the wiring structure and mounting of the position detection device, and at the same time,
It is possible to obtain a position detection device whose cost can be reduced.

(5) According to (3) above, there is no need to adjust the setting of the detection element in the position detecting device, and mounting of the detector and setting of the position detecting device are facilitated.

[Brief explanation of drawings]

FIG. 1 is a schematic enlarged perspective view of a position detection device for an actuator which is an embodiment of the present invention, and FIG. 2 is a perspective view showing a state in which the position detection device of this embodiment is mounted on an air cylinder.
Figure 3 is a circuit diagram of the position detection device of this embodiment, and Figure 4 (a
) to (6) are waveform diagrams showing output signals of each circuit element in FIG. 3. 1...Position detection device, 2...Board, 3...Detector, 3a, 3b...Detection element, 4... ...Integrated circuit element, 5゜6 ・ 7 ・ 8 ・ 9a. 10a. 1 l・12a. l 3 ・ ・ 14 ・ ・ l 5 ・ ・ 16 ・ ・ 17 ・ ・ 18 ・ ・ l 9 ・ ・ A, B ・ C, D ・ E ・ ・ ・ F, G- 8 ・ ・ ・ Light emitting diode, ・ Lead Wire, ・Case, ・Cylinder (actuator), ・Amplifier, ・Comparator, ・AND element, ・Output element, ・Cylinder body, ・Mounting groove, ・Mounting 7 lange, ・Screw, 0 piston rond, ・Supply Exhaust port, ・Mounting hole, ・Amplified signal, ・Switching signal, ・Inhibit signal, ・Output signal, ・Stroke distance, V・・・・・・Reference voltage. Patent applicant Koganei Seisakusho Co., Ltd. Agent Patent attorney Dai Tsutsui Sodo Patent attorney Satoshi Nakano Mistake 3 Diagram b b 1υO 2b

Claims (1)

[Claims] 1. A substrate is housed in one case, and a plurality of detection elements are mounted on one main surface of the substrate, and the plurality of detection elements are mutually arranged in the moving direction of the moving part of the actuator. A position detection device for an actuator, characterized in that it is displaced and built-in. 2. Claim 1, wherein the detection element and the substrate are embedded in a case integrally molded of synthetic resin.
The position detection device for the actuator described above. 3. The actuator position detection device according to claim 1 or 2, wherein the plurality of detection elements are formed in a one-chip detector.