JPH0610252Y2 - Detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a detection device, more specifically, at a position facing a displacement amount scale in which a large number of reflective portions and non-reflective portions are alternately arranged, The present invention relates to a detection device in which a photo sensor having a light emitting portion and a light receiving portion is arranged so as to be movable relative to a displacement amount scale.

(Prior Art) A small stepping motor built into office equipment such as a typewriter is usually driven by selectively switching on and off a plurality of sets of field coils, and this switching is obtained from experimental values. It is done by virtual time.

Therefore, in actual use, it is necessary to maintain the power supply voltage (current), motor load, etc. under the same conditions as during the experiment.
The motor torque cannot be used unless it is within the range including the safety factor.

By the way, as the size and weight of the device itself has been reduced, size reduction of the stepping motor itself has been demanded, and in reality, the stepping motor is used in a state close to its performance limit.

Therefore, in this type of stepping motor, an encoder is used to check whether or not the motor rotates and follows each time the field coils are switched.

As shown in FIG. 9, the conventional encoder axially stops a slit piece displacement plate 82 on a disk on a shaft 81 protruding rearward of the rear end of a stepping motor 80, and sandwiches the peripheral side of the displacement plate 82. The optical sensor 83 is arranged and configured. The optical sensor 83 is of a transmission type in which a light emitting portion 84 and a light receiving portion 85 are opposed to each other on both sides of the displacement plate 82.

The displacement plate 82 is exactly 1 / th of the angle advanced by one phase with respect to the same number of stable points (stop points) as the motor 80 itself.
It is adjusted so that it is offset by two angles. Therefore, the motor 80 is attached to the sensor 83 by the screws 86 and 87.
Is configured to be slidably adjusted by screws 88 and 89 for adjustment.

However, in the type using the slit type displacement plate 82 such as the encoder shown in FIG. 9, there is a limit to the size reduction of the slit type displacement plate 82, and it is possible to sufficiently meet the demand for the size reduction of the stepping motor itself. Can not.

For this reason, the displacement amount scale in which the reflecting portions and the non-reflecting portions are alternately arranged in the circumferential direction and the photosensor including the light emitting portion and the light receiving portion are opposed to each other, and the both can be relatively moved. An arranged encoder is used.

This encoder counts the number of times, of the light projected from the light emitting unit of the photo sensor, the reflected light reflected by the reflecting unit of the displacement scale and received by the light receiving unit of the photo sensor, and reads the displacement amount. It is a thing.

(Problems to be Solved by the Invention) According to the encoder in which the displacement amount scale and the photosensor are arranged so as to be opposed to each other and relatively movable, the encoder can be downsized and the stepping motor can be downsized. Can meet.

However, in such an encoder, the smaller the size,
It has been found that the distance between the light emitting portion and the light receiving portion of the photo sensor must be shortened and the non-reflective portion of the displacement amount scale needs to be narrowed, so that the displacement amount detection accuracy decreases.

Moreover, even when the position of the photo sensor is adjusted to maximize the detection accuracy of the photo sensor, it is extremely difficult to perform the adjustment precisely because the amount of adjustment is extremely small.

Therefore, an object of the present invention is to reduce the distance between the light emitting portion and the light receiving portion of the photo sensor without deteriorating the detection accuracy of the deviation amount and to precisely finely adjust the position of the photo sensor. An object of the present invention is to provide a detection device that can be used.

(Means for Solving the Problems) As a result of various studies conducted by the present inventor to achieve the above-mentioned object,
The light-emitting part and the light-receiving part of the photosensor are arranged in a sensor holder in which a light-shielding protrusion whose tip is formed in a trapezoidal shape or a triangular shape is provided in the middle, and two rotation fulcrums are further provided.
Each of the rotation fulcrums is combined with a member having a different length, and a sensor plate is provided with a single adjustment plate provided with a bendable portion in the vicinity of a portion to which manual displacement is applied. The inventors have found that, by contacting with each other, the bendable portion of the adjustment plate can be bent to finely adjust the position of the sensor holder and the accuracy of detecting the deviation amount can be improved, and the present invention has been reached.

That is, according to the present invention, a photosensor having a light emitting portion and a light receiving portion is provided at a position facing a displacement amount scale in which a large number of reflective portions and non-reflective portions are alternately arranged, relative to the displacement amount scale. In a detection device that is arranged so as to be movable, and detects the relative movement amount between the displacement amount scale and the photosensor,
A cylindrical sensor holder in which a light emitting portion and a light receiving portion of the photo sensor are arranged in the relative movement direction and a tip is loosely inserted into a through hole of a support plate provided so as to face the displacement amount scale. A light-shielding protrusion having a triangular or trapezoidal cross-section in the direction of the displacement scale between the light-emitting part and the light-receiving part of the sensor holder; and the support plate formed on the outer surface of the sensor holder. A holding part for pinching and rotating the collar-shaped body between the collar-shaped body that is in contact with the peripheral edge of the through-hole and the peripheral edge of the through-hole of the support plate to finely adjust the position of the sensor holder. A first adjusting rod portion that extends from the first rotation fulcrum that is movably held longer than the holding portion, and has a bendable narrow portion formed near the end that is the second rotation fulcrum; From the length between the second rotation fulcrum and the narrow portion, which extends from between the two rotation fulcrums and the narrow portion. In detecting apparatus characterized by comprising an adjustment plate of a long second adjustment rod section.

(Effect) According to the present invention, the light-shielding protrusion can block the incidence of irregular reflection on the reflection surface of the displacement scale on the light-receiving portion, and the fine adjustment of the position of the sensor holder due to the adjustment plate can be performed accurately. In addition to the fact that it can be easily done, the accuracy of detecting the deviation amount can be significantly improved.

(Example) The present invention will be described in more detail with reference to the drawings.

FIG. 1 is a partially cutaway perspective view of a stepping motor having a detection device according to the present invention, FIG. 2 is a partially cutaway side view of the motor, and FIG. 3 is a partially cutaway plan view of the motor. FIG. 5 is a front view of the displacement amount scale used in the encoder. FIG. 5 is a vertical sectional view of the detection device according to the present invention. FIG. 6 is an output signal waveform diagram of the detection device according to the present invention. FIG. 8 is a front view of an adjusting plate used in the apparatus, and FIG. 8 is a front view, a side view, and a vertical sectional view of a sensor holder used in the detecting apparatus according to the present invention.

First, a schematic configuration of the stepping motor shown by reference numeral 10 in FIGS.

The motor 10 includes a rotor 4 integrally fixed to the shaft 3. The rotor 4 is a magnet rotor in which N poles and S poles are alternately magnetized in the circumferential direction according to the number of steps. A pair of concentric winding field coils stacked in the axial direction is arranged around the rotor 4, and the inner peripheral surface of the field coil and the rotor 4 extend from both ends of the field coil and are interdigitated. The magnetic pole core is omitted in the drawing. Further, the rotor 4 and the field coil are housed in the motor housing 2, and the shaft 3 projects outward from both end surfaces 2 a, 2 b of the housing 2.

Next, the configuration of the encoder 1 including the detecting device according to the present invention will be described.

First, a disc ring-shaped displacement amount scale 5 coaxially arranged with respect to the shaft 3 is fixed to the end surface of the rotor 4. As shown in FIG. 4, this deviation amount scale 5 has stripe-shaped reflecting portions 5a ... Which extend in the radial direction in the circumferential direction of the plate surface.
And a non-reflective portion 5b are alternately arranged to form a repeating pattern. The non-reflecting portion 5b is the fifth in comparison with the reflecting portion 5a.
As shown in the figure, it has a groove shape, and each of the reflection portion 5a and the non-reflection portion 5b is formed in 48 steps.

The back surface of the displacement scale 5 is formed in a shape that is axially fitted to the end surface of the rotor 4, and is fixed by a fixing means such as an adhesive.

When the displacement scale 5 is attached to the rotor 4, the displacement scale 5 is positioned so as to have a predetermined positional relationship. That is, at the stable stop point of the rotor 4, the center of the sensor holder 6 is located exactly at the geometrical center in the circumferential direction of the reflecting portion 5 a of the displacement scale 5.

Therefore, when actually mounting the displacement scale 5 on the rotor 4, the mounting position of the sensor holder 6 with respect to the motor housing 2 and the stable stop position of the rotor 4 are known. The displacement plate 5 may be attached to the rotor 4 in such a state that the displacement plate 5 is at a fixed position.

By mounting the rotor 4 and the displacement amount scale 5 in such a positional relationship, the rotor 4 can be rotated at a constant speed in either the forward direction or the return direction, and the angular displacement between the rotor 4 and It is not necessary to adjust the positional relationship with the plate 5.

This is only the remaining adjustments in the product of the sensor holder 6 itself and the final position adjustment.

The above description is for the case where there is one sensor holder 6,
Two sensor holders may be used to detect the rotation direction (forward / reverse). In this case, as shown in FIG.
Each of the two sensor holders will be arranged at 1 and R2. That is, the sensor holders may be arranged line-symmetrically with the phases shifted from the geometrical center position of the reflection parts 5a and 5a in the forward direction or the reverse direction by the same angle. This is the same as the case of one holder.

On the other hand, on the rear end surface 2a of the motor housing 2, the sensor holder 6 is fixed to the rear end surface 2a while the position is adjusted by the adjustment plate 20.

As shown in FIG. 5, the sensor holder 6 is provided with a light emitting element 21 as a light emitting section and a light receiving element 22 as a light receiving section adjacent to each other in the rotation direction of the displacement scale 5.

The irradiation light emitted from the light emitting element 21 of the holder 6 hits the displacement amount scale 5.

Here, when the reflection part 5a of the displacement scale 5 exists, the reflected light of the irradiation light reflected by the reflection part 5a is received by the light receiving element 22, converted into an electrical signal, and output. .

On the other hand, when the non-reflective portion 5b of the displacement amount scale 5 is present, the reflected light received by the light receiving element 22 is almost eliminated, and no electric signal is output from the light receiving element 22.

Thus, the sensor holder 6 in which the light emitting element 21 and the light receiving element 22 are arranged and is provided at a position facing the displacement amount scale 6 is shown in FIGS. 8 (a) to 8 (c). .

Below the cylindrical main body 12 forming the sensor holder 6,
The opening 12a is opened, and a light-shielding protrusion 23 having a triangular cross section is provided near the center of the opening 12a.
The light-emitting element 21 and the light-receiving element 22 are arranged in the sensor holder 6 as shown in FIG.

Then, as shown in FIG. 5, the opening 1 of the sensor holder 6
When 2a is disposed so as to face the displacement amount scale 6 and the displacement amount scale 6 is moved, the waveform of the output power from the light receiving element 22 has a sharp shape as shown by S1 in FIG.

On the other hand, when the sensor holder in which the light-shielding protrusion 23 is not formed is used, the irregular reflection of the reflector 5a of the displacement scale 5 enters the light-receiving element 22, and the output voltage from the light-receiving element 22 is as shown in FIG. A broad waveform is obtained as in S2.

Further, on the side surface of the sensor holder 6, there is formed a collar-shaped body 14 which comes into contact with the rear end surface 2a of the motor housing 2 which is a support plate of the sensor holder 6 to support the sensor holder 6.

One surface of the collar-shaped body 14 has the sensor holder 6 whose tip is loosely inserted in the through hole 24 formed in the rear end surface 2a.
It contacts the peripheral edge of the through hole 24 and supports it.

Further, the other surface of the collar-shaped body 14 is pressed by the adjusting plate 20 shown in FIG. 3, and the sensor holder 6 is fixed on the rear end surface 2a while its position is adjusted.

The adjustment plate 20 is formed integrally by punching a single plate material, and as shown in FIG. 3, a first rotation fulcrum P1 for rotatably supporting the adjustment plate 20, and
A holding portion 26 that holds the sensor holder that is formed to extend from the first rotation fulcrum P1 to one side, and a first adjustment rod portion 32 that is longer than the holding portion 26 that extends in a different direction from the first rotation fulcrum.
A bendable narrow constriction portion 33 formed near the tip of the first adjusting rod 32, a second rotation fulcrum P2 located at the tip of the first adjusting rod 32, and a second rotation fulcrum P2. A second adjusting rod portion 34 is provided which extends between the narrowing portion 33 and the first adjusting rod portion 32 in a direction different from that of the first adjusting rod portion 32 and is longer than the second pivotal fulcrum P2 and the narrowing portion 33.

The details of the adjusting plate 20 used in this embodiment are shown in FIG.

As shown in FIG. 7, the adjustment plate 20 is provided with a U-shaped holding portion 26, a screw insertion hole for attaching and fixing the adjustment plate 20 to the rear end surface 2a with a screw 27 provided in the vicinity of the holding portion 26. Portion 28 and this insertion hole portion 2
8, a leaf spring portion 31 provided on the opposite side of the holding portion 26 and having a boss 30 bulging toward the rear end surface 2a.
A first adjusting rod 32 extending relatively long from the insertion hole 28, and a constricted portion 33 provided at the tip of the rod 32,
A second adjusting rod 34 including a pair of rods 34a, 34b extending from the tip of the necked portion 33 to both sides, and a protrusion formed in the center of the rod 34, and bent at a right angle to the rear end face 2a side. The locking pin portion 35 is provided.

The adjustment plate 20 is attached to the rear end surface 2a by the screws 27 inserted into the insertion holes 28 by pressing the collar-shaped body 14 of the sensor holder 6 by the holding portions 26.

At this time, the boss 30 is pressed against the rear end surface 2a, and the leaf spring portion 31
By the action of, the sensor 6 is held with a constant pressing force.
This pressing force can be kept constant by the screw 27.

On the other hand, a locking hole 36 into which the locking pin portion 35 is inserted is formed in the rear end surface 2a, and the locking pin portion 35 is rotatably locked.

With such an adjusting plate 20, the sensor holder 6
When adjusting the position of, by inserting a flat-blade screwdriver T inside the rods 34a, 34b and rotating it,
Only the distance reduced by the ratio of the length L1 between the adjusting rod 34, that is, the tips of the rods 34a and 34b and the locking pin 35, and the length L2 between the constricted portion 33 and the locking pin 35. The tip of the first adjusting rod 32 is displaced.

At this time, the first adjusting rod portion 32 rotates around the screw 27 as a fulcrum, and the constricted portion 33 bends.

On the other hand, the displacement of the first adjusting rod 32 is caused by the displacement of the first adjusting rod 32.
The sensor 6 is moved in the circumferential direction only by the minute displacement portion reduced by the ratio of the length L3 between the tip of the screw and the screw 27 and the length L4 between the screw 27 and the sensor 6 (holding portion 26).

Here, if the tip of the second adjusting rod portion 34 is moved by X1, the sensor holder 6 is displaced by the reduced X2, and its size is Becomes

Further, the transmission path is the displacement of the second adjusting rod 34 → the acting portion 37.
Displacement → folding of the constricted portion 33 → displacement of the first adjusting rod portion 32 → displacement of the holding portion 26 → displacement of the sensor 6.

In this way, by rotating the driver T, the amount of rotational displacement thereof is reduced by a so-called two-stage lever mechanism, and this is transmitted to the sensor 6 so that fine displacement can be easily adjusted.

It is to be noted that the structure is such that an appropriate pressing force is applied to the sensor 6 at the time of adjustment, and it is not necessary to tighten the screw 27 after the adjustment, so that the sensor 6 is accurately fixed without shifting.

In the above-described embodiment, the light shielding protrusion of the sensor holder 6 has a triangular cross-sectional shape.
It may be trapezoidal.

Further, although the displacement amount scale 5 is a rotary type attached to the end surface of the rotor, it may be axially fixed to the shaft or may be a linear type displacement amount scale.

Further, also in the adjusting plate, the overall shape, the extending direction of each part, the dimensions of L1 to L4, and the ratio can be arbitrarily selected and changed, and the boss and the leaf spring part may be omitted. The adjusting rod may be of a single type without a driver.

(Advantages of the Invention) According to the present invention, by using the encoder in a stepping motor or the like, it is possible to reduce the size without lowering the detection accuracy of the encoder, and to reduce the size of the stepping motor or the like.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a stepping motor having a detection device according to the present invention, FIG. 2 is a partially cutaway side view of the motor, and FIG. 3 is a partially cutaway plan view of the motor. FIG. 5 is a front view of a displacement amount scale used in an encoder. FIG. 5 is a sectional view of a detecting device according to the present invention. FIG. 6 is an output signal waveform diagram of the detecting device. FIG. 7 is a detecting device according to the present invention. FIG. 8 is a front view of an adjusting plate used for the above, FIG. 8 is a front view, a side view and a vertical sectional view of a sensor holder used in the detecting device according to the present invention.
FIG. 9 shows a perspective view of a conventional encoder. In the drawing, 2a ... Rear end surface (support plate) of the motor housing, 5 ...
Displacement scale, 6 ... Sensor holder, 20 ... Adjustment plate, 21 ... Light emitting portion (light emitting element), 22 ... Light receiving portion (light receiving element), 24 ... Through hole.

Claims (2)

[Scope of utility model registration request] 1. A photosensor having a light emitting portion and a light receiving portion at a position facing a displacement amount scale in which a large number of reflective portions and non-reflective portions are alternately arranged, relative to the displacement amount scale. In a detection device that is movably arranged and detects the relative movement amount of a displacement amount scale and a photo sensor, the light emitting unit and the light receiving unit of the photo sensor are arranged in the relative movement direction and the displacement amount is A cylindrical sensor holder whose tip is loosely inserted into a through hole of a support plate provided to face the scale, and a displacement amount between the light emitting part and the light receiving part of the sensor holder in the direction of the scale. A light-shielding protrusion formed to project in a triangular or trapezoidal shape; a collar-shaped body formed on the outer surface of the sensor holder and contacting the peripheral edge of the through hole of the support plate; and the collar-shaped body of the support plate. It is pinched and rotated between the peripheral edge of the through hole and A holding portion for finely adjusting the position, and a narrow width portion that extends from the first rotation fulcrum that rotatably holds the holding portion longer than the holding portion and is bendable near the end portion that is the second rotation fulcrum. And a second adjusting rod extending from between the second rotation fulcrum and the narrow portion and longer than the length of the second rotation fulcrum and the narrow portion. An adjusting plate comprising: 2. The detecting device according to claim 1, wherein the photo sensor is used as an encoder for a stepping motor.