JPH02122217A - Optical position detecting sensor - Google Patents

Abstract

PURPOSE:To prevent the generation of a malfunction even if an external magnet deviates from a detection range and to detect the displacement as non-contact by providing a slide magnetic material and a lock use magnet. CONSTITUTION:A slide magnetic material 4 receives suction force of an external magnet 3, and moves in a slide space 15 together with the magnet 3, when the magnet 3 moves. When the magnet 3 exceeds a detection range and moves on, the magnetic material 4 runs against an end part of the space 15 and stops, and also, locked magnetically to its position by suction force of a lock use magnet 5. When the title sensor is constituted so that a spiral-like magnetic material 2 can be sucked magnetically and constrained by this locked magnetic material 4, it receives restraint by the magnetic material 4, and a free rotation of a rotating body 1 is not generated irrespective of existence of the magnet 3. Also, when the magnet 3 is reset to its original state and returns into the detection range, the magnetic material 4 receives suction force of the magnet 3 again and moves together with the magnet 3, and a suction position of the magnetic material 2 also moves, and the rotating body 1 rotates thereby.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical position detection sensor that can detect the positional displacement of a detected object in a non-contact manner.

[Prior Art] Various shapes and configurations have been proposed for linear sensors that detect positional displacement, but optical detection sensors have mechanical or electrical contact portions and are designed to detect objects to be detected. It is possible to configure the sensor in a sealed manner with no contact between the sensor and the sensor, and there are no component parts that can cause malfunctions or accidents such as wear or spark generation, so it is not suitable for precision machinery, facilities with poor external atmosphere, or fire. It is particularly useful in facilities, etc., and has come to attract attention.

What is shown in FIG. 5 is an explanatory cross-sectional view of a conventional configuration example of such an optical position detection sensor, with the - not shown.

In the figure, reference numeral 1 denotes a rotating body made of a non-magnetic material, in which a rotating shaft 11 is attached to a body 9 with a bearing 12, and a spiral magnetic body made of a magnet or ferromagnetic material is attached to the outer periphery of the rotating body 1. Layer 2 is formed. On the other hand, there is an external magnet 3 fixed to an object to be detected (not shown) outside the body, and the egg weight I- in the figure can be moved forward or backward toward the external magnet 3 or 3-. It has a configuration. Now, when the external magnet 3 is in the position shown in FIG. 5, the part of the spiral magnetic body 2 closest to the external magnet 3 is strongly attracted by the magnetic force, and
is at rest at the position shown in FIG. When the external magnet 3 moves toward the 3 side with the movement of the object to be detected, the position to which the spiral magnetic body 2 is attracted by the external magnet 3 changes accordingly, and the rotating body 1 rotates accordingly.

This sensor is provided with a pair of optical fibers 20, 20- (only one of which is shown in the figure) supported by a separate support case 3o, and connected to a termination part 22 by a connector 21. It is configured such that light is emitted from the collimating lens 23 at the tip, and the light reflected by the reflecting mirror 8 is incident through the other collimating lens 23- (not shown). (See Fig. 6 for details) The reflecting mirror 8 is installed at a fixed position on the rotating body 1, and when the external magnet 3 moves and the rotating body 1 is rotated accordingly, the reflecting mirror 8 is reflected. The mirror 86 rotates, and the reflected light that was reflected by the reflecting mirror 8 and entered the light-receiving optical fiber is turned off.

By detecting that the reflected light is turned off, it is detected that a positional displacement has occurred in the object to be detected.

[Problem to be solved by the invention] In the sensor configured as described above, is there no problem if the object to be detected is within the movement range or the detection range, or if the object moves beyond this range? The external magnet 3 also moves accordingly and attracts the spiral magnetic body 2, thereby eliminating the constraint on the rotation of the rotating body 1. Therefore, if vibration or shock is applied to the sensor section, the rotating body 1 or the jockey may rotate, causing the above-mentioned light to turn on and off arbitrarily, causing a malfunction.

Furthermore, in the above conventional example, the light reflecting surface is configured at one point as shown in FIG. 6, and in order to match the incident angle on this reflecting surface, the optical fibers 20, 20- are It is necessary to set a certain angle and force it to be held at that angle.

Furthermore, the strength of the optical fiber against external forces is insufficient, so it is necessary to further protect the area around the optical fiber held in the above manner with a protective cage 31.Dimensionally, the optical fiber held in the sensor body is There is also the problem that the portion becomes larger, which is not practical.

The purpose of the present invention is to solve the above-mentioned problems of the prior art, and to lock the external magnet so that it does not move freely even if it moves beyond the detection range or until it returns. It is an object of the present invention to provide an optical position detection sensor that can be placed in the same position as the conventional one, and whose overall size can be reduced in size.

[Means for Solving the Problems] The present invention provides a sliding magnetic body that can move within a predetermined range parallel to the external magnet between an external magnet and a spiral magnetic body. A locking magnet capable of magnetically locking the sliding magnetic body is disposed on the side, and a plurality of optical paths parallel to the axial direction of the rotating body are provided (), and an optical fiber termination part is provided on one side of the optical path. A reflecting mirror is provided on the opposite side, and the emitted light is passed through one optical path, and the light reflected by the reflecting mirror is received at the light receiving end via the other optical path.

[Function] As the external magnet moves, the slide magnetic body moves, so a magnetic attraction effect is formed between the slide magnetic body and the spiral magnetic body. Even if it moves beyond this point, the slide magnetic body continues to restrain the rotating body, and the free rotation of the rotating body is prevented. The slide magnetic body is locked at that position by a locking magnet and does not move freely. The optical fibers can be arranged parallel to each other, the support structure can be simplified, and the overall size can be reduced.

[Example] The present invention will be described below with reference to the drawings of the embodiment 6. Figure 1 is a cross-sectional view showing a specific configuration of the sensor main body according to the present invention, and Figure 2 is a cross-sectional view showing the specific configuration of the sensor body according to the present invention. It is an AA sectional view.

Reference numeral 1 denotes a rotating body made of a non-magnetic and lightweight material such as aluminum, and its rotating shaft 11 is rotatably supported by the body 9 via a bearing 12. 2 is a magnetic layer made of a magnet or ferromagnetic material that is spirally wound 4f or embedded in the outer periphery of the rotating body 1;
3 is the external magnet mentioned above.

According to the present invention, a cover 14 also made of a non-magnetic material is provided on the outside of a case 10 made of a non-magnetic material that houses the rotary body 1, and the cover 14 is also made of a non-magnetic material, and the slider has a detection range that is approximately equal to the detection range of the external magnet 3. The space 15 is formed parallel to the moving direction of the external magnet 3, and a slide magnetic body 4 that can freely slide within the slide space 15 is disposed, while locking magnets 5. 5 is installed via an insulator 16.

In the arrangement of the magnets or magnetic bodies as described above, basically, the magnetic attraction force of the external magnet 3 acts on the spiral magnetic body 2, and as explained in the previous conventional example, the movement of the external magnet 3 is caused. Is it necessary to be able to rotate the rotating body 1 depending on the situation? Therefore, in order to have a configuration that can exert such an effect,
It is necessary to select an appropriate combination of whether the spiral magnetic body 2 is made of a ferromagnetic material or a magnet, or whether the slide magnetic body 4 is made of a ferromagnetic material or a magnet.

The slide magnetic body 4 receives the attractive force of the external magnet 3 C-1,
The displacement of the external magnet 3 moves within the slide space 15 together with the external magnet 3. When the external magnet 3 moves beyond the detection range, the slide magnetic body 4 moves into the slide space 15.
It stops when it hits the end of the locking magnet 5, and is magnetically locked in that position by the attractive force of the locking magnet 5. If the locked magnetic body 4 is configured to magnetically attract and restrain the spiral magnetic body 2, the rotating body will receive the restraining force of the sliding magnetic body 4 regardless of the presence or absence of the external magnet 3. 1 free rotation does not occur. When the external magnet 3 returns to its original state and returns within the detection range, the slide magnetic body 4 receives the attraction force of the external magnet 3 again and begins to move together with the external magnet 3, and the attraction position of the spiral magnetic body 2 is is also moved, thereby causing the rotating body 1 to rotate as explained above.

Therefore, the selection of whether the spiral magnetic body 2, the sliding magnetic body 4, and the locking magnet 5 should be made of ferromagnetic material or magnets should be made so that the above-mentioned operations can be performed appropriately. Must. Of course, if the slide magnetic body 4 is selected as the magnet, the locking magnet 5 may be composed of a ferromagnetic body.
The expression "locking magnet" includes such aspects.

On the other hand, in this embodiment, the rotating body 1 is composed of a core 1a and a rim 1b as shown in FIG. 2, and a pair of optical paths 7, 7- are formed in the core 1a parallel to the axis of the rotating body 1. The body 9 at the negative end of the optical paths 7, 7 has a mounting part 6 for attaching an optical fiber termination (not shown), and the other end has a frame for mounting a reflector. A reflecting mirror 8° 8- is installed at 13.

The positional relationship between the optical fiber termination part and the reflecting mirror is set such that when the rotating body 1 is at a specific position, they can face each other on both sides of the optical path 7. The emitted light 40 from the part passes through the optical path 7, is reflected by the reflecting mirror 8 as shown in FIG.
The reflected light 41 re-reflected by the optical fiber is configured to be able to pass through the optical path 7' and enter the receiving end of the optical fiber. Third
Figure (b) is a front sketch showing how the reflecting mirrors 8 and 8 are mounted from the front side.

The sensor according to the present invention is configured as described above,
When the external magnet 3 is located at a specific position, for example, on the right end side in FIG. 1, the spiral magnetic body 2 is attracted to a specific position corresponding to that position, and the rotation of the rotating body 1 is restrained and stopped at the specific position. Now, it is assumed that the arrangement is such that the incident and reflected light is conducted within the optical paths 7, 7- under such circumstances. When the detected object moves and the external magnet 3 moves accordingly, the attraction position of the spiral magnetic body 2 changes,
The rotating body 1 rotates accordingly, and the optical path 7,
The conduction of light within 7- is cut off, and the incident light that was on until then is turned off. This makes it possible to detect the occurrence of positional displacement in the object to be detected.

The number of optical paths is not limited to two as described above, and any number of n optical paths may be formed.

In FIG. 4, six optical paths 71 to 76 are arranged at intervals of 60 degrees. 71 becomes the path of the emitted light 7
2 becomes a reflected light path, and when the rotating body 1 rotates 60 degrees, 72 becomes an emission path and 73 becomes a reflection path. Below, for each 60 degree rotation, the exit/reflection path is Il.
Since it changes to l feed, if you display this as the number of pulses,
More detailed movement information of the external magnet 3, that is, the detected object can be obtained.

As a specific example, assume that the winding pitch of the spiral magnetic material on the rotating body is 30 nm, and the number of pulses is "2".The rotating body is 60 degrees x 2 = 12
This means that it has been rotated by 0 degrees, which is 120/360, or 1/
After three rotations, it is detected that the object to be detected has moved by 10 +nII+.

Similarly, the detection distance and accuracy can be improved by increasing the number of optical paths and suitably adjusting the pitch of the magnetic material.

In the present invention, there is no risk of the rotating body rotating freely even if the movement of the external magnet is large, as described above, or the optical paths of the emitted and reflected light are parallel, and the reflecting mirror is placed in the optical path. By installing it on the opposite side of the sensor, there is no need to add an angle to the optical fiber termination part, and the overall size can be made compact.As a result, the overall shape of the sensor can be made smaller than before. It has another characteristic that can be transformed into

[Effects of the Invention] As described above, the position detection sensor according to the present invention can exhibit the following excellent effects.

(1) Due to the arrangement of the slide magnetic body and the locking magnet, there is no risk of malfunction even if the external magnet deviates from the detection range.

(2) Displacement can be detected non-contact, and there are no parts that can cause malfunctions such as mechanical wear, so there is no chance of failure.
＜, reliability can be greatly improved.

(3) Since the optical path can be sealed using the optical method, there is no need to worry about external noise entering, and unlike electrical contacts, sparks are not emitted, making it extremely safe from an explosion-proof perspective.

(4) It is also possible to detect the positions of several points with one sensor.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG.
3(a) is an explanatory diagram showing the arrangement of the reflecting mirror, FIG. 3(b) is a front view thereof, and FIG. 4 is an explanatory diagram showing another example of the formation of the optical path. FIG. 5 is a sectional view showing a conventional example, and FIG. 6 is an explanatory diagram showing the configuration of a light reflecting portion in the conventional example. 7゜1: Rotating body, 2: Spiral magnetic layer, 3: External magnet, 4 Nislide magnetic body, 5 Locking magnet, 71-76: Optical path, 8.8-: Reflector.

Claims (1)

[Claims] (1) A spiral magnetic layer made of a ferromagnetic material or a magnet is formed on the outer periphery of a cylindrical rotating body made of a non-magnetic material, and an external magnet provided on the side of the detected object moves in the axial direction of the rotating body. A position detection sensor that attracts the spiral magnetic layer, thereby causing a rotating body to rotate, and uses the rotation to turn on and off an optical path to optically detect a positional displacement of a detected object. A sliding magnetic body made of a magnet or ferromagnetic material that can move in parallel with the external magnet is installed between the spiral magnetic body and the external magnet, and the sliding magnetic body is placed on both sides of the sliding area of the sliding magnetic body. While a magnetically lockable locking magnet is arranged, a plurality of optical paths are formed in the rotating body parallel to the axial direction of the rotating body, and the light emitting and light receiving ends of the optical fiber are connected to one side of the optical path. An optical position detection sensor that is provided with a reflecting mirror on the opposite side of the optical path facing the light emitting/receiving end, which can appropriately reflect the light emitted from one optical path to the other optical path.