JPH0628608U - Non-contact position sensor - Google Patents

Abstract

(57) [Abstract] [Purpose] A position sensor for detecting the position of a movable part that is movably attached to a fixed part, such as the movable part of a vibration tester, and in particular, the sensor is a movable part. The present invention relates to an improvement of a non-contact type position sensor that does not contact. [Structure] Six phototransistors 2 arranged so that the optical path is shielded to be "ON" or "OFF" depending on the vertical position of the movable part of the vibration tester.
a to 2f and a logic circuit 30 which operates in response to the signals, the number of logic circuits 30 is 9 based on the combination of the phototransistor in the "ON" state and the phototransistor in the "OFF" state. Of the LEDs 3a to 3j, a specific LED corresponding to the position of the movable portion is operated to be turned on so that the position of the movable portion can be displayed in a non-contact manner.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a position sensor for detecting the position of a movable part that is movably attached to a fixed part, such as the movable part of a vibration tester, and in particular, the sensor does not contact the movable part. The present invention relates to improvement of a non-contact type position sensor.

[0002]

[Prior art]

 Conventionally, a non-contact type position sensor has been proposed in which a cord is attached to a movable portion and the reflected light is detected to detect the position of the movable portion.

[0003]

[Problems to be solved by the device]

 By the way, in the conventional non-contact type position sensor as described above, since it is a reflection type, not only a great deal of labor is required for distance adjustment, but also dust attached to the code may cause an error in the detected value. . Moreover, there is a problem that a complicated circuit is required to convert the code attached to the movable portion into a digital signal.

The present invention is intended to solve such a problem, and a position detecting unit is formed by a plurality of light emitting diodes and a plurality of phototransistors arranged to face each light emitting diode. At the same time, a position display circuit is formed by a logic circuit whose input source is a signal from the phototransistor of the position detecting section, and a plurality of optical paths are formed between the light emitting diodes and the phototransistors. By shielding any one or more of them among the phototransistors as they move, the phototransistor in the light emitting state and the phototransistor in the nonlight emitting state are turned on. Based on the combination with the phototransistor, the LED corresponding to the position of the movable part is turned on via the logic circuit to detect the position of the movable part. Another object of the present invention is to provide a non-contact type position sensor.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the non-contact type position sensor of the present invention is a position sensor for detecting the position of a movable part that is movably attached to a fixed part. A position display circuit that receives the detection signal and displays the position of the movable part, and the position detection part includes a plurality of light emitting diodes mounted on the fixed part on a straight line at equal intervals. A plurality of phototransistors, which are attached to the fixed portion so as to face each light emitting diode and form a plurality of optical paths between the light emitting diode and the light emitting diode, are mounted on the movable portion. The position display circuit is arranged so that any one of the plurality of optical paths is shielded by the movement of the shutter, and the position display circuit uses the output of the plurality of phototransistors as an input signal source. The logic circuit includes a plurality of LEDs, and the logic circuit is a combination of a phototransistor which is in a light emitting state and a phototransistor which is in a non-light emitting state among the plurality of phototransistors corresponding to the position of the movable portion. It is characterized in that the LED corresponding to the position of the movable portion is turned on based on the matching.

[0006]

[Action]

 In the non-contact type position sensor of the present invention described above, one of a plurality of optical paths (single or plural) formed separately between each light emitting diode and each phototransistor as the movable part moves. ) Is blocked by the plate shutter. As a result, the plurality of phototransistors may emit light or may not emit light as the movable part moves. Then, depending on the combination of the phototransistor in the light emitting state and the phototransistor in the non-light emitting state, the logic circuit operates to turn on a specific LED corresponding to the position of the movable portion.

[0007]

【Example】

 Hereinafter, a non-contact type position sensor as an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a position detecting portion, and FIG. 2 is a schematic view showing the correlation between a light emitting diode and a plate shutter. 3 (a) is a correlation diagram between the position of the plate shutter and the phototransistor that emits light, (b) is a correlation diagram between the position of the plate shutter and the LED that is turned on, and FIG. 4 is a position display circuit diagram. FIGS. 5A and 5B are schematic diagrams for explaining the change of the resolution and the displacement limit set value.

In FIG. 1, reference numeral 10 indicates a position detecting unit, which includes a first substrate unit 10a and a second substrate unit 10b arranged in parallel, and both substrate units 10a, A void is formed between the portions 10b, and a plate-shaped shutter 21 attached to the movable portion 20 is movably disposed in this void, as will be described later. Six light emitting diodes 1a to 1f are mounted on the second substrate portion 10b in a straight line at regular intervals S. On the other hand, six phototransistors 2a to 2f face the light emitting diodes 1a to 1f, respectively, at positions on the first substrate portion 10a that face the respective light emitting diodes 1a to 1f. The optical paths 4a to 4f, which are mounted at the opposite positions with a space S therebetween, are formed between the light emitting diodes and the phototransistors facing each other, respectively. ing.

Reference numeral 21 denotes a plate-shaped shutter attached to the movable part 20 of the vibration tester, and the plate-shaped shutter 21 can freely move in the vertical direction in the space formed between the substrates 10a and 10b. The position detector 10 is attached to the vibration tester so as to be movable. Here, the six light emitting diodes 1a to 1f and the six phototransistors 2a to 2f are arranged in the same direction as the moving direction of the plate shutter 21. Further, the plate-shaped shutter 21 has a width x at the neutral position of the plate-shaped shutter 21 (state I in FIG. 2) without blocking the optical paths of the light-emitting diodes 1a and 1f at the upper and lower ends, and the other light-emitting diode 1b. The size is formed so as to block the optical path of 1e.

When the movable portion 20 is in the neutral position, the light from the light emitting diodes 1b to 1e is blocked by the plate shutter 21, and the light from the light emitting diodes 1a and 1f at the upper and lower ends is blocked. The position detecting unit 10 is arranged in the vibration tester in such a manner that only the phototransistors 2a and 2f are turned on without any change. As the movable part 20 of the vibration tester moves, the plate shutter 21 moves vertically in FIG. Therefore, the plate-shaped shutter 21 is positioned relative to the six light emitting diodes 1a to 1f and the six phototransistors 2a to 2f during movement, and is positioned at any one of (I) to (XI) in FIG. Will be taken.

That is, the plate-shaped shutter 21 is moved upward from the neutral position of (I) of FIG. 2 by one step, that is, the position of (II) moved by a dimension S corresponding to one light emitting diode (phototransistor), Further, the position of (III) moved upward by the dimension S from the position of (II) (in this case, the position moved upward by the dimension 2S from the neutral position), etc., and the optical paths of all the light emitting diodes were completely changed. It can have an unscaled (VI) overscale position. Further, the position (VII) → (XI) can be taken from the neutral position downward as in the above.

As is clear from the description of FIG. 2, at each of the positions (I) to (XI), the light emitting diodes 1 a to 1 f (and the phototransistors 2 a to 2 f) whose optical path is blocked by the plate-shaped shutter 21. ) Combination is different. FIG. 3A shows the correlation between the positions (I) to (XI) of the plate shutter 21 and the light-emitting diodes 1a to 1f whose light paths are blocked, as shown in FIG. Indicates that the optical path is not shielded, that is, the phototransistor 2a to 2f in the "ON" state, and the blank mark indicates the phototransistor in the "OFF" state because the optical path is shielded. There is.

FIG. 4 is a logic circuit for receiving the signals from the phototransistors 2a to 2f as described above and operating the plate shutter 21 to display the 11 upper and lower positions by the nine LEDs 3a to 3j. 1 shows an example of a position display circuit including a circuit 30 (composed of AND elements, NAND elements, etc.), and reference numerals 2a to 2f in FIG. 4 correspond to the phototransistors 2a to 2f described above. There is. In FIG. 4, when the plate shutter 21 is in the neutral position (I), as described in FIG. 3A, only the phototransistors 2a and 2f are “ON”. At this time, in response to the ON signals of the phototransistors 2a and 2f, the logic circuit in the position display circuit is activated and only the LED 3e is turned on.

Further, when the plate-shaped shutter 21 is in the position (II) moved up one step, only the phototransistors 2e and 2f are turned on. At this time, in response to the ON signals of the phototransistors 2e and 2f, the logic circuit of FIG. 4 operates and only the LED 3d lights up. When the plate-shaped shutter 21 moves one step further upward to the position (III), the phototransistors 2d, 2e and 2f are turned on, and at this time, the LED 3c is turned on by the operation of the logic circuit. As described above, by operating the logic circuit, it is possible to light a specific LED corresponding to each of the positions (I) to (XI) of the plate shutter 21.

The relationship between the respective positions (I) to (XI) of the plate-shaped shutter 21 and the LEDs 3a to 3j which are turned on corresponding to the positions is summarized in a table as shown in FIG. 3 (b). Note that in this table, the LED with a "○" mark is shown. Therefore, it is possible to detect the position of the plate shutter 21, that is, the movable portion 20 of the vibration tester, with accuracy according to the arrangement interval S of the light emitting diodes 1a to 1f by reading the illuminated LED. Become. The number of light emitting diodes (and phototransistors) is not limited to six, and needless to say, the precision can be improved by increasing the number.

The position display circuit shown in FIG. 4 incorporates an adder circuit 31 and an integrator circuit 32. By inserting the outputs of the phototransistors 2a to 2f into the adder circuit 31 and the integrator circuit 32, respectively. , Can be converted into analog signals. By feeding back the analog signal thus obtained to the displacement of the movable part, it is possible to control the movable part to be held at the neutral position. In the above-described embodiment, the plurality of light emitting diodes 1a to 1f and the plurality of phototransistors 2a to 2f are arranged on a straight line having an axis y that is the same direction as the moving direction Y of the plate shutter 21 [Fig. 5 (a)].

Now, as shown in FIG. 5B, the array axis of the plurality of light emitting diodes ₁ a to ₁ f and the plurality of phototransistors 2 a to 2 f with respect to the moving direction Y of the plate-shaped shutter 21 is the axis of y ₁ . When the plate shutter 21 is tilted in this way, the moving distance from the neutral position to the overscale state shown by the reference numeral 21a, that is, the dimension X ₀ in the case of FIG. 5A is the same as that in the case of FIG. 5B. Greater than dimension X ₁ (X ₀ > X ₁ ). Therefore, the resolution (accuracy) of the position sensor becomes higher in the case of FIG. 5B, that is, when the arrangement direction of the light emitting diodes and the like is inclined with respect to the moving direction of the plate-shaped shutter 21 (the inclination described above). Is larger, the resolution is higher).

In this way, it is possible to change the resolution of the sensor by changing the inclination of the array axis of the light emitting diodes. Also, the moving distance to reach the overscale is X _{0 or} X ₁ in the vertical direction from the neutral position. Therefore, the displacement limit set value of the sensor is 2X ₀ in the case of FIG. Since the case of 5 (b) is 2 × _1, it is possible to change the displacement limit set value by changing the inclination. Needless to say, even if the shape of the plate-shaped shutter is changed instead of changing the inclination angle of the array axis of the light emitting diodes, substantially the same operational effects as described above can be obtained.

[0019]

[Effect of device]

 As described in detail above, according to the non-contact type position sensor of the present invention, the following effects and advantages can be obtained. (1) The position of the movable part can be accurately detected by a simple process of attaching a plate shutter to the movable part. (2) The resolution and displacement limit can be changed by changing the shape of the plate shutter or changing the tilt angle of the array axis of the light emitting diodes. (3) Since the position sensor is composed of a plurality of light emitting diodes, a plurality of phototransistors combined with them, a plurality of LEDs, and a logic circuit, there are no moving parts, which is highly durable and does not require digital processing. Therefore, the generation of error due to noise can be suppressed.

[Brief description of drawings]

FIG. 1 is a perspective view of a position detector of a non-contact type position sensor according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a correlation between the light emitting diode and a plate shutter.

FIG. 3A is a correlation diagram between the position of the plate-shaped shutter and the phototransistor that emits light. (b) Correlation diagram between the position of the plate-shaped shutter and the LED that is turned on.

FIG. 4 is a circuit diagram showing the same position.

5A and 5B are schematic diagrams for explaining the same resolution and change of displacement limit set value.

[Explanation of symbols]

 1a-1f Light emitting diode 2a-2f Phototransistor 3a-3j LED 10 Position detection part 10a 1st board part 10b 2nd board part 20 Movable part 21 Plate type shutter

Claims (1)

[Scope of utility model registration request] 1. A position sensor for detecting the position of a movable part that is movably mounted on a fixed part, and displays the position of the movable part by receiving a detection signal from the position detection part and the same position detection part. A position display circuit is provided, and the position detection section is mounted on the fixed section facing a plurality of light emitting diodes mounted on the fixed section on a straight line at equal intervals and facing each of the light emitting diodes. And a plurality of phototransistors forming a plurality of optical paths with the respective light emitting diodes, and any one of the plurality of optical paths is shielded by the movement of the plate shutter attached to the movable part. And the position display circuit includes a logic circuit using the outputs of the plurality of phototransistors as an input signal source and a plurality of LEDs.
The movable portion is based on a combination of a phototransistor that emits light and a phototransistor that does not emit light corresponding to the position of the movable portion of the plurality of phototransistors. A non-contact type position sensor, which is configured to turn on the LED corresponding to the position.