JP2000074693A - Rotational displacement information detection device - Google Patents

Abstract

(57) [Problem] To provide a rotation displacement information detecting device that can easily and accurately position a disk unit in a direction of a rotation axis of a disk and a direction orthogonal to the direction of the rotation axis and assemble the disk unit with a main unit. To do. SOLUTION: A positioning member 11 provided with three positioning portions 11a, 11b, 11c in a substantially U-shape in a main body unit 102 is detachably fixed, and among the three positioning portions 11a, 11b, 11c of the positioning member 11, The disk unit 101 is positioned in the direction orthogonal to the rotation axis direction of the disk 3 (the direction opposite to the X direction) by using the two positioning portions 11a and 11b.
The disk unit 101 is rotated using the three positioning portions 11a, 11b, 11c in the direction of the rotation axis of the disk 3 (Z direction).
Position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational displacement information detecting device, for example, by irradiating a luminous flux to a radiation grating of a main scale (disk) and a radiation grating of an index scale (flat substrate) that relatively rotate and move. It is suitable for a rotary encoder that detects a phase obtained therefrom, or intensity-modulated signal light, and detects rotational displacement information such as relative rotational displacement information or the origin position of the main scale and the index scale. is there.

In particular, the present invention relates to a so-called built-in type rotary encoder in which a main body unit for arranging and fixing light source means, a light receiving means and an index scale and a disk unit for arranging and fixing a main scale are separate bodies.

[0003]

2. Description of the Related Art As is well known, a rotary encoder is often used as a device for measuring relative rotational displacement information (displacement, speed, acceleration, etc.) of an object with high accuracy. This kind of rotary encoder is generally provided with an origin detection function for detecting origin information in order to calculate absolute position information of rotational displacement information.

FIG. 5 shows an outline of a rotary encoder having an origin detecting function. This rotary encoder detects rotational displacement information as follows. That is, a repetitive transmission / non-transmission (or reflection / non-reflection) radiation grating pattern 4 is recorded on a disk (main scale) 3 fixed to a disk hub 8 which moves relatively, and a fixed planar substrate (index scale) is recorded. Radiation grating patterns 5A and 5B are recorded at a pitch equal to 5 and spatially shifted by 90 degrees from each other, and are superimposed at a predetermined interval (gap). 2 irradiates a parallel light beam.

At this time, the amount of transmitted light changes periodically depending on the degree of coincidence between the two patterns due to the movement of the disk 3. The amount of change at this time is detected by the corresponding light receiving element 6 (6A, 6B) provided on the sensor substrate 9 to obtain an electric sine wave incremental signal (A-phase signal, B-phase signal). Further, the signal is converted by a binarization circuit to obtain a rectangular wave incremental signal (A-phase signal, B-phase signal). Thus, the rotational displacement information of the rotating shaft 7 such as a motor is detected.

Further, the rotary encoder detects the origin information as follows. That is, a transmissive / non-transmissive (or reflective / non-reflective) origin pattern 4Z is recorded on the relatively moving disk 3, and the same origin pattern 5Z is recorded on the fixed flat substrate 5 so that both are predetermined. Are overlapped at an interval (gap) of
D1 irradiates a parallel light beam through the collimator lens 2.

At this time, a pulse-like signal light having a maximum transmitted light amount is obtained at the moment when the two patterns are completely matched by the movement of the disk 3. The pulse signal light is detected by the light receiving element 6 (6Z) provided on the sensor substrate 9 to obtain an origin signal, and the atomic signal is converted by a binarization circuit to obtain a rectangular wave origin signal.

As described above, the rotary encoder with the origin detection function utilizes both the principle of detecting the incremental signal and the principle of detecting the origin signal by using the modulation effect of the amount of transmitted light due to the change in the degree of overlap between the disk 3 and the flat substrate 5. .

[0009]

In the rotary encoder having the above-described configuration, in recent years, high resolution and miniaturization have been demanded for detecting displacement information. In particular, the demand for miniaturization is not only the size of the encoder body but also the shortening of the length in the axial direction after the encoder is mounted on a rotating body such as a motor as a detected object.

Therefore, there is a need for a so-called "built-in type" rotary encoder, in which the encoder itself does not have its own rotating shaft, and a disk is directly attached to the rotating shaft of a motor or the like, and then the encoder body is further assembled to the motor housing. Have been. That is, this rotary encoder is composed of two parts that can spatially separate a disk unit for arranging and fixing a disk, and an encoder body (detection head) for arranging and fixing LEDs, a flat substrate, and a light receiving element.

However, in this type of rotary encoder, when the disk is small (small diameter) and has high resolution, the pitch of the radial grating on the disk and the radial grating on the flat substrate becomes fine, and the radial grating on the disk and the radial grating on the flat substrate become fine. The signal output is likely to be degraded due to a relative positional deviation (azimuth deviation between the lattices) from the radial lattice on the substrate. For this reason, in the above-mentioned built-in encoder in which the user himself / herself aligns the rotary shaft with the encoder, there is a problem that it is difficult to position the disk unit and the encoder body with high accuracy.

The present invention has been made in view of the above-mentioned circumstances, and when the disk unit is assembled to the encoder main body, the disk unit can be simply arranged in the direction of the rotation axis of the disk and in a direction orthogonal to the direction of the rotation axis. Another object of the present invention is to provide a rotational displacement information detecting device that can be positioned with high precision and assembled to a main unit.

[0013]

According to the present invention, there is provided a rotational displacement information detecting apparatus comprising: (1) a radiation grating on a disk which relatively rotates a light beam from a light source means and a radiation on a flat substrate opposed to the disk; And a light beam modulated by the two radiation gratings is received by a light receiving means, and information on a relative rotational displacement between the disk and the flat substrate is detected using a signal from the light receiving means. The light source means,
A main body unit for fixedly arranging the flat substrate and the light receiving means and a disk unit for fixedly arranging the disk are formed separately, and a positioning member having three positioning portions is detachably fixed to the main body unit; The disk unit is brought into contact with two of the three positioning portions of the positioning member so as to form a substantially V-shape in a direction orthogonal to the rotation axis direction of the disk, and the disk unit is moved in the rotation axis direction of the disk. Position in the direction perpendicular to
The three positioning portions of the positioning member are brought into contact with the disk unit and the main unit in the direction of the rotation axis of the disk to position the disk unit in the direction of the rotation axis of the disk.

(1-2): a light beam from the light source means is guided to a radiation grating on a relatively rotating disk and to a radiation grating on a flat substrate opposed to the disk, and the two radiation gratings In a rotational displacement information detecting device that receives a modulated light beam by a light receiving unit and detects relative rotational displacement information between the disk and the flat substrate using a signal from the light receiving unit, the light source unit includes: A disk unit having a disk hub for fixing and arranging the flat substrate and the light receiving means and a disk hub for fixing and arranging the disk are formed separately, and a positioning member having three positioning portions in the main unit is detachable. The disk unit is fixed so that two of the three positioning parts of the positioning member are substantially V-shaped in a direction perpendicular to the rotation axis direction of the disk. The disk unit is positioned in a direction perpendicular to the direction of the rotation axis of the disk by abutting the disk hub, and the three positioning portions of the positioning member abut on the disk hub and the main unit in the direction of the rotation axis of the disk. Thus, the disk unit is positioned in the rotation axis direction of the disk.

(1-3): A light beam from the light source means is guided to a radiation grating on a relatively rotating disk and a radiation grating on a flat substrate opposed to the disk, and the light beams are guided by the two radiation gratings. In a rotational displacement information detecting device that receives a modulated light beam by a light receiving unit and detects relative rotational displacement information between the disk and the flat substrate using a signal from the light receiving unit, the light source unit includes: The main body unit for fixedly arranging the flat substrate and the light receiving means and a disk unit having a disk hub for fixing and arranging the disk are formed separately, and a shaft is attached to the disk hub, and three positioning portions are attached to the main body unit. And a positioning member having a substantially V-shape is formed on two of the three positioning portions of the positioning member in a direction orthogonal to the rotation axis direction of the disk. The disk unit is positioned in the direction perpendicular to the rotation axis direction of the disk by bringing the shaft of the disk hub into contact with the disk hub, and the three positioning portions of the positioning member are aligned with the disk hub in the rotation axis direction of the disk. The disk unit is positioned in the rotation axis direction of the disk by abutting on the main unit.

In particular, (1-4): In the rotational displacement information detecting device of (1) to (1-3), the three positioning portions of the positioning member are formed in a substantially U-shape. Features.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a schematic view of a main part of a rotational displacement information detecting device according to the present embodiment.

This embodiment shows a so-called built-in type rotary encoder (hereinafter referred to as an encoder).
As shown in FIG. 1B, a disk unit 101 and a main unit 102 are provided as basic constituent units. The encoder according to the present embodiment does not have a rotating shaft, and a user (measurer) attaches a rotating shaft 17 such as a motor as an object to be detected to the disk unit 10 as described later.
1 (see FIG. 2).

The disk unit 101 comprises a disk (main scale) 3 and a disk hub 8 integrally fixed to the disk 3. The disk 3 has, for example, a radial amplitude grating (radiation grating) 4 composed of about 2500 transmission and non-transmission slits in a donut-shaped area having a radius of 8 to 12 mm, and an origin position detection on a different circumference from the amplitude grating 4. The amplitude scales 4Z are respectively recorded to form a main scale. When assembling the disk unit 101 and the main body unit 102, the dummy rotary shaft 7 is inserted into the hole 8b and screwed to the disk hub 8, and the dummy rotary shaft 7 is attached to the disk hub 8 after the assembly is completed. More removed.

The main unit 102 includes an LED (light emitting element) 1, a collimator lens 2, a flat board (index scale) 5, a sensor (light receiving element) 6, and a sensor board 9.
And a base member 15. And LED1
The collimator lens 2 and the collimator lens 2 constitute one element as light source means, and the collimator lens 2 irradiates the disk 3 with the light beam from the LED 1 as a parallel light beam. The LED 1, the collimator lens 2, the flat substrate 5, the sensor 6, and the sensor substrate 9 are fixed to a base member 15 at predetermined positions.

The flat substrate 5 is arranged to face the disk 3 of the disk unit 101, and amplitude gratings 5A, 5B, 5Z to be described later are recorded on its surface to form an index scale. On the plane of the plane substrate 5, radial amplitude gratings (radiation gratings) 5A, which are spatially shifted 90 degrees from each other at the same pitch as the amplitude grating 4 of the disk 3,
5B is recorded. These amplitude gratings 5A, 5B
Modulates the luminous flux from the LED 1 so that the transmitted light is maximized when overlapping with the amplitude grating 4 of the disk 3 and is minimized when overlapping with a ピ ッ チ pitch shift. Then, the sensor 6 receives a light beam that has passed through the amplitude gratings 5A and 5B, so that an incremental signal (A-phase signal, B-phase signal) is obtained.

On the surface of the flat substrate 5, an amplitude grating 5Z for obtaining an origin position signal (Z-phase signal) of the rotation of the detected object is recorded in addition to the amplitude gratings 5A and 5B. . This amplitude grating 5Z is the same as the amplitude grating 4Z on the disk 3.
The light flux from the LED 1 is light-modulated so that the transmitted light is reduced when it is shifted by more than the grating width. The sensor 6 receives the light beam that has passed through the amplitude grating 5Z to obtain an origin position signal.

The sensor 6 is provided on a sensor substrate 9 and has three sensors 6A, 6B, and 6Z for detecting an A-phase signal, detecting a B-phase signal, and detecting a Z-phase signal, respectively.

Next, a method of detecting the rotational displacement information of the rotary shaft in the encoder according to the present embodiment will be described.

The encoder of this embodiment converts the light beam from the LED 1 into a parallel light beam by the collimator lens 2 and an amplitude grating 4 for detecting an incremental signal (A-phase signal, B-phase signal) of the disk 3 and an origin signal (Z-phase signal). ) Illuminate the amplitude grating 4Z for detection.

As a result, the light flux transmitted through the amplitude grating 4 and the amplitude grating 5A is received by the sensor 6A, and an A-phase signal is obtained.
The light transmitted through the amplitude grating 4 and the amplitude grating 5B is detected by the sensor 6
B is received and a B-phase signal is obtained.
The light flux transmitted through Z is received by the sensor 6Z to obtain a Z-phase signal.

That is, the sensors 6A and 6B detect a change in the amount of light in one cycle when the disk 3 and the plane substrate 5 move relative to each other by one pitch of the amplitude grating 4, and have a phase of 90 degrees.
Incremental signals shifted by degrees (A-phase signal, B-phase signal)
Is output. The analog signals output from the sensors 6A and 6B are binarized into an A-phase rectangular wave signal and a B-phase rectangular wave signal. The A-phase rectangular wave signal and the B-phase rectangular wave signal are counted, and the detected object is detected. Obtain rotation displacement information of the rotating shaft. For example, when the A-phase signal changes from “L” to “H”, if the state of the B-phase signal is “H”, “1” is added to the count value, and the state of the B-phase signal is “L”. If "", "1" is subtracted from the count value.

Further, several small mountain-shaped waveforms are output from the sensor 6Z on both sides of one large mountain-shaped waveform in accordance with the relative rotational movement of the disk 3. The half-value width of the large mountain-shaped waveform substantially coincides with the rotation corresponding to the width of the slits of the amplitude gratings 4Z and 5Z. Therefore, this signal is binarized at a レ ベ ル level to obtain a rectangular Z-phase signal.
The width of the Z-phase rectangular wave signal coincides with the rotation corresponding to the width of the slit of the amplitude grating 5Z. Further, the origin signal (Z
The incremental signal (A-phase signal) and the origin signal (Z-phase signal) are synchronized to count the incremental signals (A-phase signal and B-phase signal) based on the phase signal). That is, the rising and falling timings of the Z-phase signal are completely matched with the rising and falling timings of the A-phase signal. If the synchronization processing is described in detail, the signal width of the Z-phase signal is substantially determined by the rotation of the slit width of the amplitude grating 5Z as described above. The width of the Z-phase signal is set twice as large as the width of the "H" level of the A-phase signal. Then, the amplitude grating 4 on the disk 3,
By setting the recording positions of the amplitude gratings 5A and 5B on the plane substrate 5 and the amplitude gratings 4Z and 5Z on the disk 3 and the plane substrate 5 at appropriate positions, the "H" of the rectangular wave signal of the Z-phase signal is set. One of the "H" levels of the rectangular wave signal of the A-phase signal is completely (centered) included in the "level". Thereafter, the A-phase signal and the Z-phase signal are logically processed (AND) to obtain an origin signal (Z-phase signal) completely synchronized with the A-phase signal.

As described above, the encoder for detecting two kinds of signals (incremental signal and origin signal) is provided on the disk 3 to simplify the assembling.
Are integrally fixed to a disk hub 8 to form a disk unit 101, and furthermore, an LED 1, a collimator lens 2,
The main body unit 102 is configured by mounting the flat substrate 5, the sensor 6, and the sensor substrate 9 on the base member 15.
Then, the amplitude grating 4 on the disk 3 and the amplitude grating 4Z for detecting the origin are collectively illuminated by one LED 1, and the amplitude gratings 5A and 5B and the amplitude grating 5Z for detecting the origin are further formed on the same plane substrate 5. In addition to recording in parallel, sensors 6A, 6B and 6Z for detecting an incremental signal and an origin signal are arranged in parallel on the same sensor substrate 9.

In the encoder of the present embodiment configured as described above, the disk unit 101 and the main unit 102 are fixed using a positioning member described later when packing the product, as shown in FIG. At this time, A
In order to synchronize the phase signal and the Z-phase signal, it is necessary to suppress the eccentricity of the disk (main scale) 3 and the X-axis component of the displacement of the plane substrate (index scale) 5. Here, for example, as a main scale, a radius of 8 to 12 mm
When the disk 3 on which 2,500 amplitude gratings 4 are recorded in the donut-shaped area is used (see FIG. 2), it is necessary to suppress the deviation of the X direction to 21 μm or less in the detection accuracy of the rotational displacement of the detected object. This deviation is the sharpest value in all directions.

In this embodiment, the disk unit 101
The displacement in the X direction is suppressed by assembling the main unit 102 and the positioning unit 11 described later.

As shown in FIG. 1A, the positioning member 11 has a U-shape in a plane (XY plane) orthogonal to the rotation axis direction (Z direction) of the disk 3. It is composed of three rod-like members 11a, 11b, 11c as three formed positioning portions, and a fixing member 11d provided on the rod-like member 11a located at the center among the three rod-like members 11a, 11b, 11c. Have been. Hereinafter, three U-shaped rod members 11a, 11b,
11c, the central rod member 11a connected to the fixing member 11d is referred to as a first rod member, and one rod member 11b connected to the first rod member 11a is referred to as a second rod member. The other bar 11c connected to the first bar 11a is referred to as a third bar. Fixing member 11d
Is provided substantially at the center of the first rod-shaped member 11a and extends outward in the radial direction of the disk 3. The positioning member 11 is attached to the fixing member 11d.
5 for screwing a screw 13 to be fixed to 5
e is provided.

Next, the assembly of the encoder according to the present embodiment will be described.

First, the base member 1 of the main unit 102
The disk hub 8 is mounted on a dummy rotating shaft (hereinafter, referred to as a dummy shaft) 7 inserted into the insertion hole 15 a provided in the disk 5, and the eccentricity of the disk 3 is adjusted. At this time, the disk hub 8 is screwed to the dummy shaft 7. The main unit 102, the positioning member 11, and the disk unit 101 are mounted on a tool. Each bar-shaped member 11a, 11 of the positioning member 11 is placed on the base member 15 of the main unit 102.
b, 11c to the disk hub 8 of the disk unit 101
Insert toward. At this time, the positioning member 11 abuts the second rod-shaped member 11b without any gap against the abutting surface 12 provided on the surface of the base member 15 of the main body unit 102, and the first rod member 11b contacts the outer peripheral side surface of the bearing portion 8a of the disk hub 8. Then, a screw 13 is screwed into the screwing portion 11e to fix the positioning member 11 to the base member 15 of the main unit 102 (FIG. 1).
(A) and (B)).

The positioning of the disk unit 101 by the positioning member 11 will be described with reference to FIGS.
As shown in the figure, in the rotation axis direction (Z direction) of the disk 3, that is, in the axial height direction of the dummy shaft 7, each of the rod-shaped members 11a,
The contact positions A, B, and C on the upper surfaces of 11b and 11c and the lower surface 8D of the disk hub 8 are abutted and positioned.
The direction (X) orthogonal to the rotation axis direction (Z direction) of the disk 3
The bearing 8a of the disc hub 8
The inner surface a of the first rod-shaped member 11a in contact with one surface a 'of the outer surface of the bearing member 8 and the inner surface b of the second rod-shaped member 11a in contact with the other surface a of the outer surface of the bearing portion 8a have V They are abutted and positioned. That is, the disk unit 10 is formed by using two of the three bar members 11a, 11b, and 11c of the positioning member 11.
1 is positioned in a direction orthogonal to the direction of the rotation axis of the disk 3, and the height position of the disk unit 101 in the direction of the rotation axis of the disk 3 of the disk unit 101 is determined by using three rod members 11 a, 11 b, and 11 c. As described above, the disk unit 101 is provided with the respective bar-shaped members 11a, 11a of the positioning member 11.
b and 11c are abutted against the disk hub 8 to perform three-dimensional positioning.

At this time, the rotational phase of the disk 3 is set at the time of detection of the Z-phase signal. In this state, the position adjustment in the X direction, the Y direction, and the Z direction of the sensor substrate 9 on which the planar substrate 5 on which the sensor 6 and the amplitude gratings 5A, 5B, and 5Z are provided is performed. The mechanism for adjusting the position of the sensor substrate 9 is not shown. Thus, the assembly of the disk unit 101 to the main unit 102 is completed. After the mounting of the disk unit 101 to the main unit 102 is completed, the dummy shaft 7 is removed from the disk hub 8 and delivered to the user.

Next, a case where the user uses the encoder by attaching it to the rotating shaft of the detected object will be described. It is assumed that the rotating shaft 17 to be attached by the user has a shaft diameter different from the shaft diameter of the dummy shaft 7 used at the time of assembling the encoder.

When assembling the encoder, the user attaches the disk hub 8 to the rotating shaft 17 and mounts the main body unit 102 in the direction of the arrow shown in FIG. 1, that is, the bearing 8a of the disk hub 8 and the bearing 8a. The center line direction (X) of the V-shaped portion surrounded by the first rod-shaped member 11a and the second rod-shaped member 11b of the contacting positioning member 11
(In the direction opposite to the direction) to hit the rotating shaft 17. Thereafter, the disk unit 101 is abutted from above to below, and is also positioned vertically.

Disk unit 101 and main unit 1
After fixing 02, the screw 13 is removed from the screwing portion 11e of the positioning member 11, the screwing of the positioning member 11 and the main unit 102 is released, and the positioning member 11 is pulled out of the main unit 102, and the disk unit 101 is removed. The connection of the main unit 102 is released.

Even if the shaft diameter changes, if the V-shaped portion of the positioning member 11 is installed so as to face the Z-phase signal detection direction, the center of rotation of the disk 3 due to the change in the shaft diameter is determined. The displacement occurs only in the Y direction and does not affect the synchronization between the A-phase signal and the Z-phase signal (see FIG. 2). Also, the connection between the disk hub 8 and the rotating shaft 17 is made in the direction connecting the amplitude grating 4Z for detecting the Z-phase signal and the center of the disk 3 (the direction opposite to the X direction). Has only an effect in the Y direction and does not affect the synchronization between the A-phase signal and the Z-phase signal (see FIG. 3). In FIG. 3, reference numeral 16 denotes a screw for connecting the disk hub 8 and the rotating shaft 17.

As described above, in the encoder according to the present embodiment, when the disk unit 101 detects the Z-phase signal, the disk unit 101 can stably synchronize the A-phase signal and the Z-phase signal without displacement in the X direction. become. Therefore, the encoder according to the present embodiment has an advantageous configuration in that the A-phase signal and the Z-phase signal can be stably synchronized without any displacement in the X direction as described above. Further, the positioning member 11 can be formed at a low cost by simply bending a rod-shaped member such as a wire, and the positioning of the main unit 102 and the disk unit 101 can be performed with high precision.

[Embodiment 2] FIG. 4 shows a built-in encoder according to this embodiment.

The encoder of the present embodiment is the same as the encoder of the first embodiment except that the shape of the disk hub 8 and the abutting surface at the time of positioning by the positioning member 11 are different from the encoder of the first embodiment. It is configured. That is, in the present embodiment, the positioning of the disk unit 101 by the positioning member 11 in the direction orthogonal to the rotation axis direction (Z direction) of the disk 3 (the direction opposite to the X direction) is performed using the dummy shaft 7. ing.

Regarding the positioning of the disk unit 101 by the positioning member 11 in this embodiment, as shown in FIGS. 4A and 4B, the rotation axis direction (Z direction) of the disk 3, that is, the dummy axis 7, the disk unit 101 is abutted and positioned by the contact portion on the upper surface of each of the rod-shaped members 11a, 11b, 11c and the lower surface of the disk hub 8 as in the first embodiment. In the direction (the direction opposite to the X direction) orthogonal to the rotation axis direction (Z direction) of the disk 3, the inner surface of the first rod-shaped member 11 a contacting one surface of the outer surface of the dummy shaft 7 and the dummy shaft 7 is a second rod-shaped member 11a in contact with the other outer surface of
And a V-shaped abutting position with the inner side surface. That is, three rod-shaped members 11 in the positioning member 11
a, 11b, and 11c, two rod-shaped members 11a, 11
b, the disk unit 101 is positioned in a direction orthogonal to the direction of the rotation axis of the disk 3, and the three rod-shaped members 1
Disk unit 101 using 1a, 11b, 11c
Of the disk 3 in the direction of the rotation axis. In this manner, the disk unit 101 is three-dimensionally positioned by the rod members 11a, 11b, 11c of the positioning member 11 abutting against the disk hub 8 and the dummy shaft 7.

Also in the encoder according to the present embodiment having such a configuration, the dummy shaft 7 of the disk hub 8, the first rod-shaped member 11 a of the positioning member 11 in contact with the dummy shaft 7, and the second rod-shaped member 11b can be installed so as to face the detection direction of the Z-phase signal, so that the displacement of the rotation center of the disk 3 due to the change in the shaft diameter occurs only in the Y-direction and the A-phase This has no effect on the synchronization between the signal and the Z-phase signal. Also, since the connection between the disk hub 8 and the rotating shaft (not shown) is made in the direction (Z direction) connecting the amplitude grating 4Z for detecting the Z-phase signal and the center of the disk 3, the eccentricity when the disk unit is mounted is similarly set. Has only an effect in the Y direction and does not affect the synchronization between the A-phase signal and the Z-phase signal. Therefore, the same effects as in the above-described embodiment can be obtained with the configuration of the present embodiment.

As described above, according to this embodiment, the positioning member 11 having the U-shaped rod members 11a, 11b, 11c is fixed to the main unit 102, and the positioning members 11a, 11b, 11c of the respective rod members 11a, 11b, 11c are fixed. Two of the rod members 11a and 11b are connected to the disc hub 8 or the dummy shaft 7.
To make a V-shape, the disk unit 10
1 is positioned in a direction orthogonal to the rotation axis direction of the disk 3 (the direction opposite to the X direction), and
a, 11b, 11c are replaced by the disk hub 8 and the base member 15;
To position the disk unit 101 at the height of the disk 3 in the rotation axis direction (Z direction). After the user installs the encoder, the positioning member 11 is pulled out from the main unit 102. Therefore, even if the disk 3 of the built-in encoder is made small (small diameter) and high in resolution, the disk unit 101 is rotated in the direction of the rotation axis of the disk 3 and in a direction orthogonal to the direction of the rotation axis.
Of the main unit 10 by simply and accurately positioning
2 can be assembled.

In this embodiment, the positioning member 11
The rod members 11a, 11b, and 11c are formed in a U-shape.
The shapes of b and 11c are not limited to the U-shape, and the other rod-shaped members 11a and 11c are different from the central rod-shaped member 11b.
11c may have a substantially U-shape extending in the radial direction of the disk hub 8.

[0048]

As described above, according to the rotational displacement information detecting device of the present invention, the disk unit is easily and accurately positioned in the direction of the rotation axis of the disk and in the direction orthogonal to the direction of the rotation axis. It can be assembled to the main unit.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a main part of an encoder according to a first embodiment.

FIG. 2 shows a V composed of two rod-shaped members as positioning members.
Figure showing character-shaped part

FIG. 3 is a view showing a screwing direction between a disk hub and a rotating shaft.

FIG. 4 is a schematic diagram of a main part of an encoder according to a second embodiment.

FIG. 5 is a schematic diagram of a conventional embedded encoder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LED (light source means) 3 Disk 4, 4Z amplitude grating (radiation grating) 5 Planar board 5A, 5B, 5Z amplitude grating (radiation grating) 6, 6A, 6B, 6Z Sensor (light receiving means) 7 Dummy axis (axis) 8 Disk hub 11 Positioning member 11a, 11b, 11c Rod-shaped member (positioning portion) 101 Disk unit 102 Main unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 AA39 BB03 BB16 BB27 CC22 DD02 DD03 FF18 GG07 GG12 HH03 HH13 JJ01 JJ05 LL10 LL41 MM04 PP18 QQ04 QQ51 TT02 2F077 AA25 AA46 NN02 NN27 TT11Q32 NN27 TT11

Claims (4)

[Claims] 1. A light beam from a light source means is guided to a radiation grating on a relatively rotating disk and a radiation grating on a flat substrate opposed to the disk, and a light beam modulated by the two radiation gratings is transmitted. A rotational displacement information detecting device that receives light by a light receiving unit and detects relative rotational displacement information between the disk and the flat substrate by using a signal from the light receiving unit; the light source unit, the flat substrate, and the light receiving unit; A main body unit for fixedly disposing the means and a disk unit for fixedly disposing the disk are formed separately, and a positioning member having three positioning portions is detachably fixed to the main body unit;
The two positioning parts of the three positioning parts of the positioning member are substantially V-shaped in a direction perpendicular to the rotation axis direction of the disk.
The disk unit is brought into contact with the disk unit to position the disk unit in a direction perpendicular to the rotation axis direction of the disk, and the three positioning portions of the positioning member are aligned with the disk unit in the rotation axis direction of the disk. A rotation displacement information detecting device, wherein the disk unit is positioned in the rotation axis direction of the disk by abutting on the main unit. 2. A light beam from a light source means is guided to a radiation grating on a relatively rotating disk and a radiation grating on a flat substrate opposed to the disk, and a light beam modulated by the two radiation gratings is transmitted. A rotational displacement information detecting device that receives light by a light receiving unit and detects relative rotational displacement information between the disk and the flat substrate by using a signal from the light receiving unit; the light source unit, the flat substrate, and the light receiving unit; A main body unit for fixedly arranging the means and a disk unit having a disk hub for fixedly arranging the disk are formed separately, and a positioning member having three positioning portions is detachably fixed to the main body unit; The disk hub of the disk unit is brought into contact with two of the three positioning portions so as to form a substantially V-shape in a direction perpendicular to the rotation axis direction of the disk. The disk unit is positioned in a direction perpendicular to the direction of the rotation axis of the disk, and the three positioning portions of the positioning member are brought into contact with the disk hub and the main unit in the direction of the rotation axis of the disk. The rotational displacement information detecting device is characterized in that the disk is positioned in the rotation axis direction of the disk. 3. A light beam from a light source means is guided to a radiation grating on a relatively rotating disk and a radiation grating on a flat substrate opposed to the disk, and a light beam modulated by the two radiation gratings is transmitted. A rotational displacement information detecting device that receives light by a light receiving unit and detects relative rotational displacement information between the disk and the flat substrate by using a signal from the light receiving unit; the light source unit, the flat substrate, and the light receiving unit; The main body unit for fixedly arranging the means and the disk unit having a disk hub for fixedly arranging the disk are formed separately, a shaft is attached to the disk hub, and a positioning member having three positioning portions is removed from the main body unit. Fixed as possible,
The two positioning parts of the three positioning parts of the positioning member are substantially V-shaped in a direction perpendicular to the rotation axis direction of the disk.
The disk unit is positioned in a direction perpendicular to the direction of the rotation axis of the disk by abutting the shaft of the disk hub so as to form a letter, and three positioning portions of the positioning member are positioned in the direction of the rotation axis of the disk. A rotation displacement information detecting device, wherein the disk unit is positioned in the rotation axis direction of the disk by abutting the hub and the main unit. 4. The positioning member according to claim 1, wherein the three positioning portions of the positioning member are formed in a substantially U-shape.
The rotational displacement information detection device according to any one of claims 1 to 3.