JPH02253190A - Moving position detecting mechanism - Google Patents

Abstract

PURPOSE:To surely detect a reference position by providing lower-order rotating body groups adjacent to one another and providing a rotating body group consisting of plural rotating bodies which are rotated 1/n times at each time of one rotation of the lowest-order rotating body of these rotating body groups. CONSTITUTION:Optical reflectors 10, 11, and 12 are stuck to position '0' of a rotating body 7, position '5' of a rotating body 8, and position '1' of a rotation body 9 respectively. In this case, a reflection photosensor 13 outputs a detection signal each time when the rotating body 8 comes to position '5', and a reflection photosensor 15 outputs a detection signal each time when the rotating body 9 comes to position '1', and these detection signals are inputted to a controller 16. Since a controller 16 detects the time when an AND condition of detection signals of reflection photosensors 13 to 15 is true, the output is obtained from the controller 16 when rotating bodies 9, 8, and 7 simultaneously come to positions '1', '5', and '0' respectively, that is, a moving body 4 comes to position '150mm', and thus, the accurate position is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a movement position detection mechanism for detecting the movement position of a moving object such as an optical microscope or a stage of a machine tool.

[Prior Art] Conventionally, various mechanical and electrical mechanisms have been known as mechanisms for detecting the moving position of a moving body. Typical examples thereof are shown in FIGS. 3 and 4.

3 and 4 show conventional examples of different mechanical movement position detection mechanisms, and in the figures, 31 is
A driving source includes a motor and a reduction gear train provided as necessary, 32 is a guide rail, 33 is a threaded rod, 34 is a moving body, and 35 is a photosensor.

First, in the one shown in FIGS. 3(a) and 3(b), a threaded hole is cut in the moving body 34 to be screwed into the threaded rod 33.
When the threaded rod 33 is rotated by the drive source 31, the movable body 34 moves in the direction of arrow B along the guide rail 32. The moving direction of the movable body 34 can be reversibly changed by the rotating direction of the drive source 31.

On the other hand, an optical reflector 36 is attached to a part of the moving body 34. A light shielding body 37 with a window 38 provided at a predetermined position (reference position) is installed on the surface where this optical reflector 36 exists, and a reflective type A photosensor 35 is installed.

Then, when the movable body 34 moves in the direction of arrow B and the reflector 36 comes to the position of the window 38, the reflective photosensor 3
A signal is generated from 5 to detect that the moving body 34 is at a reference position, that is, the origin. In addition,
The moving distance of the moving body 34 from this reference position is measured by a measuring device such as a rotary encoder (not shown).

Furthermore, the devices shown in FIGS. 4(a) and 4(b) are used in cases where it is not possible to install a reflective photosensor 36 or the like near the moving object 34 as shown in FIG. 3 due to space constraints or other factors. It is something. Note that the drive mechanism of the movable body 34 is the same as that shown in FIG. 3, so a description thereof will be omitted.

In the movement position detection mechanism shown in FIG. 4, first, the rotation of the drive source 31 is transmitted via a gear train 41 to a threaded rod 42 into which a nut 43 is screwed. Here, a pin 44 is provided upright on the nut 43, and the pin 44 is engaged with an elongated portion 46 formed on a guide member 45. Therefore, driving source 3
1, the nut 43 moves in the direction of the arrow C in synchronization with the movement of the movable body 34 in the direction of the arrow C.

On the other hand, an optical reflector 36 is attached to the upper surface of this pin 44, and a reflective photosensor 35 is installed at a predetermined position (reference position). Then, when the reflector 36 of the pin 44 moves to a position facing the reflective photosensor 35, a signal is generated from the photosensor 35, and at the same time, the movable body 34 moves to the reference position (
The position at the origin is indirectly detected.

The distance traveled from the reference position can be measured in the same manner as in FIG. 3.

In addition to the mechanical movement position detection mechanism described above,
Electrical moving position detection mechanisms are also known. For example, if the drive source of a moving object is a step motor, the number of drive pulses to drive the step motor is electrically counted, and the moving position of the moving object is detected from the count value. I can give you what you are trying to do.

[Problems to be Solved by the Invention] However, in the above-mentioned mechanical movement position detection mechanism, (1) In either case, the mechanism must be quite large and require a considerable amount of space.

■In the case shown in Fig. 3, it is necessary to process the window 38 with high precision, and it is also necessary to prepare a long light shielding body 37.
It is extremely difficult to assemble and manufacture.

(2) In the case of FIG. 4, if an attempt is made to reduce the space, it may be possible to increase the reduction ratio of the gear train 41, but the detection accuracy will decrease accordingly.

■When setting a large number of reference positions (positions to be detected), as many photosensors as 35
is necessarily required, and the configuration of the device becomes increasingly complex due to the need to assemble the light shielding plate, the device becomes larger, and the cost also increases.

There was a problem.

Further, the above-mentioned electrical position detection mechanism has the following problems. In other words, especially when a moving object must be driven with a large torque, due to the relationship with the resonance frequency of the mechanical system, although a drive command pulse is generated, it may actually be 1 to 2 pulses. Misfeeding may occur. In such cases, the number of drive pulses and the actual moving position of the moving object will deviate slightly, so the above method of indirectly measuring the moving position by counting the number of drive pulses does not directly measure the moving position. There is a problem in that reliability in terms of accuracy is lower than that of mechanical detection mechanisms that perform position detection.

The present invention was made in view of these circumstances, and is small, inexpensive, extremely easy to manufacture, has high detection accuracy, and sets an arbitrary number of reference positions greater than the number of photosensors. It is an object of the present invention to provide a moving position detection mechanism that can also be used.

[Means for Solving the Problems] In order to achieve the above object, the moving position detection mechanism of the present invention detects the moving position of a moving body, in which the moving position detection mechanism detects the moving position of a moving body. A rotating body group consisting of a plurality of rotating bodies that rotate step by step by 1/n rotation (n is an integer of 2 or more) every time the rotating body rotates once is provided, and the lowest rotating body of the rotating body group is moved as described above. A rotating body position detecting member is connected to a rotating shaft of a drive source of the body, and a rotating body position detecting member is arranged at a predetermined position of the rotating body of the rotating body group, and further at a position opposite to the rotating body on which the rotating body position detecting member is arranged. The present invention is characterized in that a sensor is installed to detect the rotating body position detection member.

[Operations and Effects of the Invention] The moving position detecting mechanism of the present invention detects the position using a group of rotary counter-type rotating bodies, so the moving position detecting mechanism can be significantly miniaturized, and it can also be used with existing decimal rotary counters. If you use , it will be dramatically easier to manufacture and can be manufactured at a very low cost.

Furthermore, it is possible to reliably detect the reference position in minute units, and the detection accuracy can be improved. Furthermore, by arranging a plurality of rotating body position detection members on each rotating body, it is possible to detect more reference positions than the number of sensors simply by installing the same number of sensors as the number of rotating bodies.

[Example] Examples will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of one embodiment of the moving position detection mechanism of the present invention, and FIG. 2 is a side view of the rotating body in the embodiment of FIG. Threaded rod, 3 is a guide rail, 4 is a moving body, 5 is a group of rotating bodies, 6 to 9 are rotating bodies,
10 to 12 are optical reflectors, 13 to 15 are reflective photosensors, 16 is a controller, and 17 is a bearing.

In FIG. 1, the drive mechanism of the movable body 4 is basically the same as that described in the conventional technology, and a drive source 1 consisting of a motor and a reduction gear train provided as necessary drives the drive mechanism to a bearing 17. When the threaded rod 2 is rotated, the movable body 4 screwed onto the threaded rod 2 and engaged with the guide rail 3 moves in the direction of arrow A along the guide rail 3. Similarly, if the rotation direction of the drive source 1 is changed, the moving direction of the moving body 4 is also changed.

Next, the moving position detection mechanism of the present invention will be explained. In FIG. 1, a plurality of rotating bodies 6 to 6 forming a rotating body group 5 are shown.
9 are each connected to an adjacent rotating body in a special relationship. In other words, each time the lower rotating body (the right rotating body in the case of the one shown in FIG. 1) makes one rotation, the adjacent upper rotating body performs an incremental rotation (step rotation) by 1/n rotation. This is what is being done. For example, when the rotating body 6 rotates once, the rotating body 7 above it rotates 1/n, and when this operation is repeated and the rotating body 7 rotates once, the rotating body 8 above it rotates 1/n. .

Note that here, n is an integer of 2 or more.

The mechanism of the rotating body group 5 is widely known as a so-called decimal rotary counter, in which numbers 0 to 9 are assigned to each of the multiple rotating bodies at equal rotation angle intervals, and the lower rotation Every time the body rotates once, the upper rotating body rotates 1/10 to indicate the state of carryover and displays the number of revolutions, etc., and is used to display the number of revolutions in various fields including tape recorders. It is widely used as a means.

Then, among the group of rotating bodies 5 incorporating such a rotary counter type mechanism, the lowest rotating body 6 is connected to the drive source 1 of the moving body 4. This connection may be made directly or via a suitable gear train.

Furthermore, as shown in FIG. 2, reflective photosensors 13 to 15 are provided to face predetermined positions of the rotating bodies 7 to 9, and optical sensors 13 to 15 are provided at desired locations on the rotating surfaces of the rotating bodies 7 to 9. Attach target reflectors 10 to 12. Then, the detection signals of the reflective photosensors 13 to 15 are input to the controller 16, and it is detected when these AND conditions are satisfied.

Next, in the moving position detection mechanism of the above embodiment, when the value of n is 10, the thread pitch of the threaded rod 2 is 1■, and the rotating body 6 is connected in a one-to-one relationship with respect to the rotation of the drive source 1. The operation will be explained using as an example.

In this case, when the drive source 1 rotates once, the movable body 4 moves by one pitch, that is, one step, on the threaded rod 2, but at the same time, the lowest rotating body 6 rotates once, so the second The rotating body 7 rotates in steps of one scale. Furthermore, as mentioned above, when the rotating body 7 rotates once, the rotating body 8 rotates once.
Similarly, when the rotating body 8 makes one rotation, the rotating body 9 rotates by one scale. Therefore, from this relationship, one scale of the rotating bodies 7 to 9 described above corresponds to the amount of movement of the moving body 4, respectively.
This corresponds to o in.

For this reason, each of the optical reflectors 10 to 12 attached to an arbitrary location on each of the rotating bodies 7 to 9 has an area of 1 m-1 of the moving body 4.
It represents the reference position in units of 0 mm and 100 mm.

To explain this point with a more specific example,
Now, the optical reflector 10 is attached to the "0" position of the rotating body 7, the optical reflector 11 is attached to the "5" position of the rotating body 8, and then the optical reflector 11 is attached to the "1" position of the rotating body 9. optical reflector 12
Suppose that you paste . In this case, the reflective photosensor 13 outputs a detection signal every time the rotating body 7 comes to the rOJ position, and the reflective photosensor 14 outputs a detection signal every time the rotating body 8 comes to the rOJ position.
The reflective photosensor 15 outputs a detection signal each time the rotating body 9 comes to the "1" position, and each time the rotating body 9 comes to the "1" position, the reflective photosensor 15 outputs a detection signal, which is input to the controller 16. On the other hand, the controller 16 controls the AN of the detection signals of these reflective photosensors 13 to 15 as described above.
Since it detects when condition D is satisfied, the controller 16 indicates that the rotating body 9 is "1" and the rotating body 8 is "1".
5", when the rotating body 7 simultaneously occupies each position of "0",
That is, an output is obtained only when the moving body 4 comes to the position r150 mml. By this, 1mm
The reference position of the moving body 4 can be detected accurately in units of units.

+1- Furthermore, in the above example, if the total effective travel of the moving body 4 is, for example, 0 to 300 am, the optical reflector 10
In addition to ~12, the "0" position of the rotating body 8 and the rotating body 9
If another optical reflector is attached to the "0" and "3" positions of
When the robot reaches each position, an output signal is obtained, and in addition to the reference position, the positions at both ends of the effective travel can also be detected.

Also, in the above example, we explained the case where the reference position is set at 1'm, but if multiple optical reflectors are attached as in the case of detecting both end positions above, multiple reference positions can be set. Needless to say, it can be done. In addition, instead of increasing the number of optical reflectors, multiple reference positions can be set by increasing the number of reflective photosensors and shifting the position of the reflective photosensors to face each rotating body. can do. Note that when a plurality of reference positions are provided, in order to distinguish each reference position from the output signal of the controller 16, the initial position of the moving body 4, the moving direction of the moving body 4, and the number of output signals from the controller 16 are used. It can be easily determined by combining information such as whether the

In the above embodiment, the optical reflector is attached to the rotating bodies 7 to 9, but if it is also attached to the rotating body 6, the optical reflector can be attached to the rotating body 6. It goes without saying that the reference position can be set to a unit of 1 mm.

Furthermore, the number of rotating bodies forming the rotating body group 5 is not limited to four, and for moving bodies that move on long guide rails, the number of rotating bodies can be added sequentially. The distance you can run can be increased by an order of magnitude.

Further, in the above embodiment, a combination of a reflective photosensor and an optical reflector is used as a member for detecting the position of each rotating body, but in short, it is sufficient to detect the position of each rotating body. For example, it is possible to obtain a detection signal by combining a photosensor, a light source, and an optical transmitter.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a diagram showing the configuration of one embodiment of the moving position detection mechanism of the present invention, Fig. 2 is a side view of the rotating body in the embodiment of Fig. 1, and Fig. 3 is a conventional FIG. 4 is a diagram showing another conventional movement position detection mechanism. DESCRIPTION OF SYMBOLS 1... Drive source, 2... Threaded rod, 3... Guide rail, 4... Moving body, 5... Rotating body group, 6-9...
Rotating body, 10-12... Optical reflector, 13-15.
... Reflective photo sensor, 16... Controller, 1
7...Bearing. Applicant: JEOL Ltd.

Claims (2)

[Claims] (1) In a moving position detection mechanism for detecting the moving position of a moving body, a plurality of units rotate in steps of 1/n rotation (n is an integer of 2 or more) for each rotation of an adjacent lower rotating body. A rotating body group consisting of rotating bodies is provided, and the lowest rotating body of the rotating body group is connected to a rotating shaft of a drive source of the moving body, and at a predetermined position of the rotating body of the rotating body group. A moving position detection mechanism characterized in that a rotating body position detecting member is arranged, and a sensor for detecting the rotating body position detecting member is further installed at a position facing the rotating body on which the rotating body position detecting member is arranged. (2) The moving position detection mechanism according to claim 1, wherein the group of rotating bodies is a decimal rotary counter.