JPH1090007A - Position detection sensor - Google Patents

Abstract

(57) [Problem] To provide a novel position detection sensor capable of detecting an object to be detected at three positions on a movement path with one sensor. A concave light guide prism having two corner reflecting surfaces and a central gap, a light-shielding shutter having a deflecting reflecting surface formed at the tip and disposed in the gap, and movement of a detection object. And a lever-shaped actuator 6c for operating the light-shielding shutter in and out of the gap of the light guide prism by following the above operation.
And a photoelectric converter 7 having a light projecting element 7a and two light receiving elements 7b and 7c and connected to the optical switch 6 through optical fibers 9 and 10, Following the movement, the actuator activates the light-blocking shutter of the optical switch in accordance with each detected position of the detected object.
(a) The light-shielding position shown in the figure, the deflection position shown in the figure (b), and the light-transmitting position shown in the figure (c) are moved into and out of the light-transmitting position shown in the figure. I do.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting sensor for detecting an object moving along a moving path at three positions on the moving path.

[0002]

2. Description of the Related Art An object to be detected that moves along a moving path is
Conventionally, limit switches are often used as detection means for detecting at a predetermined position on the movement route. Here, a conventional feed nut position detecting device is illustrated by using a feed mechanism that detects a feed nut moving on a shaft of a spindle that is rotationally driven by a motor at each of positions I, II, and III and controls movement thereof. FIG. In the drawing, 1 is a spindle, 2 is a feed nut that moves along the axis of the spindle 1, 3 is a drive motor of the spindle 1, 4 is a striker interlocked with the feed nut 2, and is set on the axis of the spindle 1. Three lever-type limit switches 5I to 5III are arranged along the movement locus of the striker 4 corresponding to the detection positions I, II and III of the feed nut 2.

[0003] With this configuration, when the feed nut 2 reaches the detection positions I, II, and III in the feed stroke in which the feed nut 2 is moved on the axis of the spindle 1 by the rotation of the motor 3, the striker is set at each detection position. 4 pushes the lever 5a of the limit switch to perform a swinging operation, whereby the limit switch is operated to output a detection signal. Then, based on this detection signal, for example, the drive motor 3 is controlled to stop.

[0004]

As described above, in the conventional position detecting device employing the limit switches, it is necessary to install the limit switches in a number corresponding to the number of detected positions, and therefore, position detection is performed at multiple points. If necessary, the number of limit switches used increases and the cost increases.

Since the rotational speed of the spindle 1 and the linear movement position of the feed nut 2 are in a proportional relationship, it is conceivable to employ, for example, a rotary encoder or the like as position detecting means, but the rotary encoder is expensive. In addition, there is a problem that the signal processing is complicated. The present invention has been made in view of the above points, and an object of the present invention is to provide a novel position detection sensor configured to be able to detect an object to be detected at three positions on a movement path using one sensor. It is in.

[0006]

According to the present invention, in order to attain the above object, a detecting unit of a position detecting sensor is displaced in accordance with the movement of an object to be detected. The actuator and the two detection elements are linked to each other so as to have two detection elements that are individually turned on and off in response to each other. It can be realized in the following form.

[0007] 1) As a detecting portion of the position detecting sensor, there are two corner reflecting surfaces and a gap crossing an optical path between the corner reflecting surfaces, and a bottom surface corresponding to the corner reflecting surface and the gap. A concave light guide prism having a light entrance portion and two light exit portions on its side, a light-blocking shutter having an obliquely cut deflecting reflection surface at the tip and disposed opposite the gap, and interlocking with the object to be detected An optical switch consisting of an actuator for operating the light-blocking shutter in and out of the gap of the light guide prism in accordance with the movement of the striker is adopted, and a light-receiving part and a light-emitting part of the light switch are provided separately from the photoelectric converter. The built-in light-emitting unit and the two light-receiving units are interconnected via an optical fiber, and actuators that follow the movement of the striker correspond to three positions of the object to be detected. Shielding the jitter of the light guide prism, deflection,
The apparatus is configured so that the object to be detected is detected at three positions based on the output signal of the light receiving unit of the photoelectric converter which is switched to the position where the light is transmitted. Further, as the actuator of the optical switch, a striker which is driven by the object to be detected, for example, a lever type actuator which swings by being driven by a striker composed of a combination of a fork lever and a cam can be adopted.

In the above arrangement, when the detected object moves at each of the three detection points on the movement path, the lever-type actuator of the optical switch swings correspondingly to change the lever angle, and The light-shielding shutter is displaced to the light-shielding, deflecting, and light-transmitting positions with respect to the light guide prism in accordance with the lever angle, and correspondingly, the output signals of the first and second light receiving units built in the photoelectric converter are collectively output. change.

That is, at the light-shielding position, the light beam entering the light-entering portion of the light-guiding prism through the light-projecting optical fiber is blocked by the light-shielding shutter and does not reach any of the two light-emitting portions. Therefore, the output signals of both the first and second light receiving units of the photoelectric converter are “0”. On the other hand, at the deflecting position, the deflecting reflection surface formed at the tip of the light-shielding shutter faces the optical path of the light guide prism. As a result, the optical signal incident from the light incident portion of the light guide prism is reflected by the deflecting and reflecting surface of the shutter while passing through the gap to change its direction, and is connected to the first light emitting portion corresponding to the gap. The light is guided to the first light receiving unit of the photoelectric conversion unit through the optical fiber for use. Therefore, the output signal of the first light receiving unit is “1”, and the output signal of the second light receiving unit is “0”. In the light-transmitting position, since the light-blocking shutter escapes from the gap of the light guide prism, the optical signal incident from the light-entering section passes through the gap and then passes through the opposite corner reflecting surface to the second light-emitting section. And the light is guided to the second light receiving portion of the photoelectric converter through the light receiving optical fiber. Therefore, the output signal of the second light receiving unit is “1”, and the output signal of the first light receiving unit is “0”.

Therefore, the output signal of the light receiving section of the photoelectric converter is discriminated by the subsequent logic circuit, so that one optical switch and the photoelectric converter are combined to move the object to be detected on the moving path of the optical switch. Can be detected by position. In addition, by using an optical switch as the detection unit, it can be used safely even in an operating environment in which a contact type limit switch cannot be used because of explosion proof and electrical insulation.

2) The first and second two built-in switches as the detecting portion of the position detecting sensor and the first and second built-in switches are operated so as to open and close each switch in accordance with the movement of the striker interlocking with the object to be detected. An actuator linked to the second built-in switch, and a plunger individually linked between the actuator and the first and second built-in switches, and the operation order of the first and second built-in switches is changed. For the plunger that is installed with the relative position shifted and that faces the first built-in switch with the fastest operation order,
A structure is provided with stopper means for restricting the range of the operation stroke so as not to exceed the operation position of the built-in switch. Further, as the actuator in the above configuration,
Similarly to the first solution, a lever-type actuator that swings by the movement of the striker that follows the object to be detected can be employed.

With this configuration, when the detection object moves at each detection point on the movement path, the lever angle of the lever actuator changes correspondingly as in the case of the conventional lever limit switch. Here, at the first first detection position, the actuator swings to the retracted position, and the first and second built-in switches incorporated in the sensor do not operate and are both in the OFF state. On the other hand, when the object to be detected moves to the next second detection position, the lever angle of the actuator changes and the two plungers operate simultaneously in a stroke. However, the first and second built-in switches move relative to the plunger. Are shifted from front to back, the first built-in switch having the earlier operation order reverses from OFF to ON first, and the second built-in switch remains OFF. Further, when the detected object moves from the detection position to the third detection point, the lever angle of the actuator further changes and pushes the plunger. The first built-in switch that has performed the inversion operation at the time is kept ON. In this operation process, the plunger corresponding to the first built-in switch does not advance further from the operation limit position of the switch by the stopper means, but absorbs the forward movement of the actuator by a spring inserted between the plunger and the actuator. I do.

Thus, a different combination of opening and closing operations of the first and second built-in switches can be obtained for each of the three positions for detecting the object to be detected, and the operation signals of the first and second built-in switches are obtained. Is processed by a logic circuit, for example,
An object to be detected that moves along the movement path can be accurately detected at three points by the position detection sensors of the table.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention corresponding to the embodiments 1) and 2) will be described below with reference to the drawings. In the drawings of the embodiment, the same members corresponding to FIG. 7 are denoted by the same reference numerals. [Embodiment 1] FIGS. 1 to 4 show an embodiment of an optical switch system according to claims 2 and 4 of the present invention. In this embodiment, as shown in FIGS. 1 (a) to 1 (c), a position detecting sensor combines a lever-type optical switch 6 as a detecting unit and a separate photoelectric converter 7 and connects them to each other. The structure is interconnected by optical fibers.

In the above description, the optical switch 6 has a structure in which a concave light guide prism 6a and a light shielding shutter 6b are incorporated in a case, and a lever-shaped actuator 6c projects upward from the case. Here, as shown in FIG. 4, the light guide prism 6a has left and right corner reflecting surfaces 6a-.
A gap 6a-3 formed by notching the upper center so as to cross the optical path between 1, 6a-2, and a corner reflecting surface 6a-
1, 6a-2, the light-entering portion 6a-4 arranged on the bottom side of the prism and the first and second light-emitting portions 6a-5, 6a-6 are formed in correspondence with the gap portions 6a-3, respectively. And this light incident part 6
a-4, and the first and second light emitting portions 6a-5 and 6a-6, respectively, the light emitting optical fiber 8 wired between the photoelectric converter 7 and the first and second light receiving optical fibers 9, 10 is inserted and connected. Further, the light-shielding shutter 6b is inclined at an angle of 45 ° with its tip end facing the light-entering side corner reflecting surface 6a-1.
To form a structure in which the deflecting reflection surface 6b-1 is formed. Further, as shown in FIG. 2, the lever-type actuator 6c has a base portion of the lever pivotally supported on the case so as to be able to swing in the left-right direction with respect to the case. The cam 6c-1 is connected. Reference numeral 6b-2 denotes an urging spring that presses the light-shielding shutter 6b toward the cam 6c-1.

On the other hand, the photoelectric converter 7 includes a light projecting element 7a such as a laser diode, and two first and second light receiving elements 7b and 7c, and the light projecting element 7a, the first and second light receiving elements are provided. The elements 7b and 7c and the optical switch 6 described above are interconnected via a light emitting optical fiber 8 and light receiving optical fibers 9 and 10. Incidentally, a photoelectric position detecting sensor for two-position detection combining an optical switch having the same configuration as described above and a photoelectric converter is described in Japanese Patent Application Laid-Open No. 4-338914 previously proposed by the same applicant as the present invention. Have been.

In the construction of the illustrated embodiment, the lever-type actuator 6c of the optical switch 6 and the position of the light-shielding shutter 6b associated with the actuator 6c with respect to the light-guiding prism 6a correspond to the drive cam 6c-1 shown in FIG. Are set so as to have the following correlation. That is, FIG.
4A, when the lever of the actuator 6c is swinging to the left (detection position I), the light-blocking shutter 6b is deeply inserted into the gap 6a-3 of the light guide prism 6a. The shutter 6b is located at a "light-shielding position" in which the optical signal that has entered and is incident on the light guide prism 6a through the light projecting optical fiber 8 is blocked by the side surface of the shutter 6b. 1 (b) and 4 (b)
When the lever of the actuator 6c is in the neutral position (detection position II), the light-shielding shutter 6
b rises from the detection position I, and the deflecting / reflecting surface 6b-1 moves to the "deflection position" facing the optical path of the light guide prism 6a. Further, as shown in FIGS. 1 (c) and 4 (c), when the lever of the actuator 6c is tilted to the right (detection position III), the light shielding shutter 6b is moved from the gap 6a-3 of the light guide prism 6a. It is adjusted to move to the "light transmission position" where it escapes and does not block the optical path.

With such a configuration, the light emitting element 7 of the photoelectric converter 7
When the actuator 6c swings to the “light-shielding position” in FIG. 1A while the optical signal is being projected to the light guide prism 6a of the optical switch 6 through the optical fiber 8, the light incident on the light guide prism 6a The signal is shielded by the shutter 6b. Therefore, the optical signal is not transmitted to any of the first and second light receiving elements 7b and 7c, and is not transmitted to the light receiving elements 7b and 7c.
The output signals A and B of c both become “0”. On the other hand, when the actuator 6b swings to the "deflection position" in FIG. 1B, the light signal incident on the light guide prism 6a is reflected by the deflection reflection surface 6b- of the light-shielding shutter 6b as can be seen from FIG. 4B. The light is reflected to 1, is deflected downward, and is transmitted to the first light receiving element 7b through the first light receiving optical fiber 9. As a result, the output signal A of the first light receiving element 7a changes to "1",
The output signal B of the light receiving element 7c remains “0”. Further, when the actuator 6b swings to the “light transmitting position” in FIG. 1C, the optical signal incident on the light guiding prism 6a is
As shown by (c), the light passes through the gap 6a-3 as it is and is transmitted to the second light receiving element 7c through the optical fiber 10.
As a result, the output signal A of the first light receiving element 7b becomes "0",
The output signal B of the second light receiving element 7c switches to "1".

Therefore, the output signals A and B are input to a decision circuit (attached to the photoelectric converter 7) of a logic circuit as shown in FIG.
The three states (detection positions I, II, and III) corresponding to the lever angle of the actuator 6c are determined by the output signals i, ii, and i of the determination circuit.
ii. 1 (a) to 1 (c)
If the position detection operation described in the above is expressed as a truth value, the following Table 1
It looks like

[0020]

[Table 1] Next, FIGS. 5A to 5C show a position detecting device in which the above-described position detecting sensor is applied to a feed mechanism similar to that described with reference to FIG. That is, in FIG. 5, a striker 4 interlocking with the movement of the feed nut 2 moves on the shaft of the spindle 1 with a fork lever 4b having one end supported by a support shaft 4a and an end of the fork lever 4b. The optical switch 6 having the above-mentioned configuration is arranged so as to oppose the roller of the lever with the cam surface of the cam 4c.

In this configuration, when the feed nut 2 moves to the detection positions I, II, and III set on the axis of the spindle 1, the cam 4c of the striker 4 rotates through the fork lever 4b following the movement. Then, the lever type actuator 6c of the optical switch 6 in contact with the cam 4c is swung. Here, the striker 4 is moved so that the detection positions I, II and III of the optical switch 6 shown in FIGS. 1 (a) to 1 (c) correspond to the detection points I, II and III of the feed nut 2 in FIG. If the fork lever 4b and the cam 4c are set, the arrival of the feed nut 2 moving on the axis of the spindle 1 at the detection positions I, II, and III can be detected based on the output signals A and B of the photoelectric conversion unit 7. .

[Embodiment 2] FIGS. 6A to 6C show an embodiment of a limit switch type position detecting sensor according to the third and fourth aspects of the present invention. In this embodiment, first and second built-in switches (micro switches) 11 and 12 in a switch case, and two plungers 13 and 14 individually facing the push buttons of the switches 11 and 12,
A driving member 15 extending between the plungers 13 and 14 is incorporated, and a lever-type actuator (a lever with a cam similar to that shown in FIG. 2) 16 for stroke-operating the driving member 15 in the direction of the arrow is supported by the case and protrudes upward. Configuration.

Here, the first and second built-in switches 11,
Numerals 12 are juxtaposed with respect to the driving member 15 such that the first built-in switch 11 is positioned forward of the second built-in switch 12 with respect to the driving member 15 so that the relative position is shifted back and forth. The plunger 13 facing the first built-in switch 11 is connected to the driving member 15 via a compression spring 17 and has a stopper on the case side facing the dog 13a projecting sideways from the plunger 13. 18, which constitute a stopper mechanism that regulates the range of the operation stroke of the plunger 13 so as not to exceed the operation position of the first built-in switch 11. On the other hand, the plunger 14 is directly connected to the driving member 15.

With this configuration, when the lever of the actuator 16 swings to the left (detection position I) as shown in FIG.
4 is retracted, and the built-in switches 11 and 12 are turned off.
When the lever of the actuator 16 swings to the neutral position (detection position II) as shown in FIG.
3 and 14 are simultaneously pressed to perform a stroke operation. However, as described above, since the first built-in switch 11 is located at a position forward of the second built-in switch 12, the first built-in switch 11 has the first operation order. Of built-in switch 11
Inverting operation from F to ON, the second built-in switch 12
It remains as FF. Further, when the lever of the actuator 16 swings rightward (detection position III), the actuator 16 performs a stroke operation to push the plunger 14 through the driving member 15, and the second built-in switch 12 is turned on from OFF. Invert operation. On the other hand, the first built-in switch 11 is kept ON since the dog 13a of the plunger 13 hits the stopper 18 and stops at that position. In this operation process, the plunger 13 corresponding to the first built-in switch 11 does not advance from the operation position of the switch by the above-mentioned stopper means, and the spring 17 inserted between the plunger 13 and the driving member 15 does not move. Absorbs the forward movement of the driving member 15.

The following table shows the operation states of the first and second built-in switches 11 and 12 corresponding to the detection positions I, II and III as truth values.

[0026]

[Table 2] Therefore, the open / close operation signals of the first and second built-in switches are input to the discriminating circuit of the logic circuit and signal-processed in the same manner as described with reference to FIG. 3 so that three states corresponding to the lever angle of the actuator 6c ( The detection positions I, II, and III) can be detected as output signals of the determination circuit.

The position of the nut 2 is set on the axis of the spindle 1 by replacing the limit switch type position detecting sensor of this embodiment with the optical switch 6 in the position detecting device of FIG. It can be detected at point detection positions I, II and III.

[0028]

As described above, according to the configuration of the present invention, only one position detection sensor is arranged along the movement path of the object to be detected, and three points are set on the movement path. Position detection is advantageous in terms of installation space and cost as compared to the conventional position detection method that can detect the target and detects the position of the target by arranging limit switches as many as the number of position detection points. A sensor can be provided.

In particular, according to the second aspect of the present invention, one optical switch can detect three positions of the object to be detected, and the surrounding environment in which a contact-type limit switch cannot be used in terms of explosion proof and electrical insulation. It has the advantage that it can be used safely under conditions.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a configuration and an operation of a position detection sensor corresponding to a first embodiment of the present invention, where (a), (b), and (c) are diagrams illustrating operating states at different detection positions, respectively.

FIG. 2 is a specific configuration diagram of a lever-type actuator in FIG. 1;

FIG. 3 is a logic circuit diagram for determining the output signal of the photoelectric converter in FIG. 1;

FIG. 4 is a diagram showing a relationship between a position where a light-shielding shutter is protruded and retracted of an optical switch in FIG. 1 and a light signal transmission path corresponding to the light-guiding prism, wherein (a) to (c) are FIGS. Diagram showing the state corresponding to c)

FIG. 5 is an explanatory diagram of a configuration and operation of a position detection device for a detected object constructed by employing the position detection sensor of the present invention;
(a) to (c) are diagrams showing operating states at different detection positions.

FIG. 6 is an explanatory diagram of a configuration and an operation of a position detection sensor according to the second embodiment of the present invention, wherein (a), (b), and (c) are diagrams showing operating states at different detection positions, respectively.

FIG. 7 is a configuration diagram of a conventional position detection device using a limit switch.

[Explanation of symbols]

 Reference Signs List 1 spindle (moving axis of object to be detected) 2 feed nut (object to be detected) 4 striker 5 lever 5I, 5II, 5III lever-type limit switch 6 optical switch 6a light guiding prism 6a-1, 6a-2 corner reflecting surface 6a- 3 Air gap 6a-4 Light entrance 6a-5, 6a-6 Light exit 6b Light-shielding shutter 6b-1 Deflection / reflection surface 6b-2 Urging spring 6c Lever actuator 6c-1 Cam 7 Photoelectric converter 7a Light emitting element 7b , 7c light receiving element 8 light emitting optical fiber 9,10 light receiving optical fiber 11,12 built-in switch 13,14 plunger 13a dog 15 drive member 16 lever type actuator 17 spring 18 stopper I, II, III detection position

Claims (4)

[Claims] 1. A position detecting sensor for detecting the position of an object to be detected at three positions on its movement path, wherein an actuator whose detection section is displaced in accordance with the movement of the object to be detected.
And individually turned on in response to the displacement of the actuator,
Position detection, comprising: two detection elements that are turned off; wherein the actuator and the two detection elements are linked so that the operation state of each of the detection elements is different for each of the three positions of the object to be detected. Sensor. 2. The position detecting sensor according to claim 1, wherein
The detection section has a gap portion crossing the optical path between the two corner reflection surfaces and the corner reflection surface, and a light incident portion on the bottom side corresponding to the corner reflection surface and the gap portion, and A concave-shaped light-guiding prism formed with two light-emitting parts,
A light-shielding shutter having a diagonally cut deflection reflection surface formed at the end and disposed opposite to the gap, and the light-shielding shutter being moved into and out of the gap of the light guide prism by following the movement of a striker interlocking with the object to be detected. An optical switch comprising an actuator, wherein a light-entering part and a light-emitting part of the optical switch are interconnected via an optical fiber between a light-emitting part incorporated in a photoelectric converter separately provided and two light-receiving parts; Actuators that follow the movement of the light source move the light-blocking shutter of the optical switch corresponding to the three positions of the detected object to block the light-guiding prism.
It is characterized in that the object to be detected is detected at three positions based on the output signal of the light receiving portion of the photoelectric converter which is switched to the position of deflection and light transmission, and switches in accordance with the position of occurrence. Position detection sensor. 3. The position detecting sensor according to claim 1, wherein
An actuator associated with the first and second built-in switches so that the detection unit opens and closes each switch in accordance with the movement of the striker interlocking with the object to be detected, the first and second two built-in switches. And a plunger for individually linking the actuator and the first and second built-in switches, and disposing the first and second built-in switches with their relative positions shifted so as to change their operation order. A position detecting sensor comprising stopper means for restricting a range of an operation stroke of a plunger opposed to a first built-in switch having a fast operation order so as not to exceed an operation position of the built-in switch. 4. The position detection sensor according to claim 2, wherein the actuator is a lever-type actuator that swings by the movement of a striker that follows the object to be detected.