JP3472034B2 - Rotational displacement information detection device - Google Patents

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, irradiating a main scale radiation grating and a index scale (radiation grating) mounted on a flat substrate with a light beam, and irradiating the light flux there. It is suitable for a rotary encoder that detects the relative rotational displacement information between the main scale and the plane substrate and the rotational displacement information such as the origin position by detecting the phase- or intensity-modulated signal light obtained from.

In particular, it is suitable for a so-called built-in rotary encoder in which the light source means, the light receiving means, the main body unit for fixing the index scale and the disk unit for fixing the main scale are separate bodies.

[0003]

2. Description of the Related Art Conventionally, a rotary encoder (hereinafter referred to as "encoder") is often used as a device for measuring relative rotational displacement information (displacement amount, velocity, acceleration, etc.) of an object with high accuracy. ing. Further, this encoder is provided with means for detecting the origin information in order to calculate the absolute position information of the rotation information.

FIG. 6 is a schematic view of a main part of a conventional encoder.

In FIG. 6, an incremental signal (A phase, B phase) detection mechanism in an encoder is repeatedly radiated by transmission or non-transmission (or reflection or non-reflection) on a main scale 3 fixed to a disk hub 8 which moves relatively. The radial grating pattern 5 in which the grating patterns 4 and 4Z are recorded and the phases are spatially shifted from each other by 90 degrees at exactly the same pitch on the fixed plane substrate (index scale) 5 as well.
A and 5B are recorded, both are superposed at a predetermined interval (gap), and then the light flux from the LED 1 is illuminated on both as a parallel light flux via the collimator lens 2.

At this time, the amount of transmitted light periodically changes according to the degree of coincidence between the patterns due to the movement of the scale. The amount of change at this time is detected by the light receiving element 6 (6A, 6B) provided on the base member 9 to obtain a sinusoidal electric incremental signal. Alternatively, it is further converted into a rectangular wave by a binarization circuit to obtain an electrical incremental signal. From this, the rotation information of the rotary shaft 17 is detected.

The origin signal (Z-phase) detection mechanism records a plurality of transmission / non-transmission (or reflection / non-reflection) radiation grating patterns 4Z on the main scale 3 which moves relatively, and a fixed index scale. The same radiation grating pattern 5Z is recorded in 5 as well, both are superposed at a predetermined interval (gap), and then both are illuminated with a parallel light flux. At this time, the pulsed signal light having the maximum amount of transmitted light is obtained at the moment when the two patterns are completely matched by the movement of the main scale 3. Light receiving element 6 provided with this pulsed signal light on the base member 9
The origin signal is obtained by detection at (6Z). Further, an electric origin signal converted into a rectangular wave by a binarization circuit is obtained.

The main scale 3 and the index scale 5 for detecting relative rotational displacement information are provided with a radiation grating pattern and an origin pattern, respectively. In many cases, both are detected simultaneously and in parallel by the same optical system. In this case, both the principle of detecting the incremental signal and the principle of detecting the origin signal utilize the effect of modulating the amount of transmitted light due to a change in the degree of overlap between the main scale 3 and the index scale 5.

[0009]

Recently, encoders are required to have smaller size as a whole and higher resolution for detecting rotational displacement information. In particular, the demand for miniaturization is not limited to simply the size of the encoder body, but is also required to reduce the length in the axial direction after the encoder is attached to a rotating body such as a motor. Therefore, recently, there is a so-called "built-in type" encoder in which the encoder itself does not have its own rotating shaft, but the 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. Is required. In this built-in type encoder, the disk (main scale) and the encoder body (detection head) are spatially separated.

When a user (measurer) attaches such an encoder to a motor, for example, a process of fixing the disk to the rotary shaft of the motor and a process of fixing the encoder body to the motor housing are required.

In that case, the encoder correctly outputs the A phase and the B phase.
Phase, the Z-phase device signals is output, parallel (a-1) to the radial grating tracks on the disk is not eccentric in rotation of the motor shaft (a-2) the radial grating tracks the encoder body on the disk It is necessary that the radial grid tracks on the substrate (on the index scale) exactly overlap each other.

When the disk is actually attached to the motor shaft, the center of rotation of the motor shaft and the center of the radial grid on the disk are displaced due to an error in the component dimensions. Further, the radial grid track on the disk and the radial grid track on the parallel substrate in the encoder body are also displaced due to an error in the mounting portion between the motor housing and the encoder body.

Generally speaking, when the disk (main scale) becomes small (small diameter) and has high resolution, it is on a radial grating on the disk and on a flat substrate (on the index scale).
The pitch of the radial grating becomes fine, and the signal output is apt to deteriorate due to the relative positional deviation (azimuth deviation between the gratings).

For example, as shown in FIG. 7, a radius of 8 to 12 m
A disk 3 having 2500 radial gratings 4 recorded in a donut-shaped area of m is adhered to a perforated hub 8 of φ6. It is assumed that the radial center of the radial grating 4 is aligned with the hole center of the perforated hub 8 with an error of the order of several microns, and the eccentricity is suppressed as much as possible. This is a disk unit 101.

The disk unit 101 and the shaft 7 of the motor are inserted in a H7 fitting relationship of φ6 mm and fastened with a set screw 20 from the side of the hub of the disk unit 101. Since a maximum gap of 35 microns occurs when H7 with a hole or axis of φ6 is fitted, eccentricity is produced at a maximum of 17.5 μm. Since the shaft 7 of the motor actually has a fitting relationship with the inner ring of the bearing built into the motor, there is a possibility that the outer shape of the shaft 7 of the motor is eccentric to the center of rotation of the same degree or more. The eccentricity of the radial grating of the disc 3 after being crushed can total 35 μm.

Further, when the encoder body is attached to the motor housing, it is practically difficult to provide the motor housing with a highly accurate fitting contact part, apart from the encoder body. When positioning and fixing with a medium precision contact relationship, a gap of about 100 μm is generated, so that the mounting position of the encoder body may shift in the x and y axis directions by about 50 μm.

Now, as shown in FIG. 8, the disk 3 is decentered by 35 μm in the x-axis direction, and the encoder body having the index scale 5 is -50 μm in the x-axis direction (the plane substrate (index scale) 5 is -50 μm). Consider the case of deviation.

The radial grating 4 on the disk 3 has a radius of 10 m.
and the grating pitch is 25 μm. The amplitude grating 4Z having a random pitch for the origin on the disk 3 has a radius of 6 to 8
It is assumed that it is recorded in mm. As the sum of the eccentricity of the disc 3 and the mounting position error of the encoder body, the disc 3
And the plane substrate 5 are displaced by 85 μm in the x-axis direction.

Assuming that the A-phase signal is detected at a disk radius of 10 mm, the A-phase detection timing is 85/25 =
3.4 cycles off. Disk radius 7mm for Z phase signal
The detection timing of the Z phase is 85 /
25 × 7/10 = 2.38 deviated. The A-phase and the Z-phase are relatively 3.4-2.38 = 1.02 cycles (however, the rectangular-wave signal of the A-phase is used as a reference for one cycle). That is, Z
The phase waveform is ± 1.02 with respect to the phase A waveform due to the relative x-direction shift of 85 μm between the encoder body and the disk.
The period equivalent is shifted.

In this case, it is difficult to synchronize the Z phase and the A phase as they are with a logic circuit. If the relative mounting error is proportional to the relative displacement between the A phase and the Z phase, the allowance for synchronization by the logic circuit is ± 0.25.
Since it is a cycle, the x-axis azimuth deviation must be within 21 μm. It is a big problem that an error of 35 μm may occur when the disk 3 is attached to the shaft 7 of the motor.

As described above, when the encoder disk 3 has a small size (small diameter) and a high resolution, the pitch of the radial grating on the disk 3 and the radial grating on the plane substrate 5 becomes fine, and the relative positional deviation (grating and grating) occurs. The azimuth deviation between the two causes the signal output to be easily reduced, and the built-in type encoder is extremely difficult to incorporate, making it very difficult to put into practical use.

The present invention provides (b-1) a light source means, a light receiving means (sensor) for a disk unit having a disk (main scale),
When the main body unit having an index scale (planar substrate) or the like is formed separately, by using a V-shaped block in which the disk unit and the main body unit are appropriately formed, positioning in the rotation axis direction and / or the rotation axis Positioning on a plane perpendicular to
An object of the present invention is to provide a rotary displacement information detecting device suitable for an embedded encoder capable of detecting rotary displacement information with high accuracy with little synchronization deviation between the A-phase signal and the Z-phase signal.

(B-2) Further, by appropriately screwing the disk hub to which the disk is fixed and the rotary shaft, the rotational displacement suitable for the built-in type encoder in which the A phase signal and the Z phase signal are less likely to be out of synchronization. An object is to provide an information detection device.

(B-3) Further, to provide a rotational displacement information detecting device suitable for an embedded type encoder in which the disk unit and the main body unit are positioned with high accuracy by a V-shaped block having an appropriate V-shaped angle. To aim.

[0025]

According to a first aspect of the present invention, there is provided a rotational displacement information detecting apparatus comprising: a radiation grating provided on a disk which relatively rotates a light beam from a light source means; and a flat substrate arranged to face the disk. Of the radiation grating and the light beam that has undergone optical modulation by the grating is received by the light receiving means, and the signal from the light receiving means is used to rotate the disk and the plane substrate relative to each other. In a rotational displacement information detecting device for detecting displacement information, a main body unit for fixedly arranging the light source means, a flat substrate, and a light receiving means and a disk unit for fixedly arranging the disk are separately configured. And on the plane orthogonal to the rotation axis of the main unit
The positioning, performs a V-shaped blocks engaged to the body unit as the slope to form a V-shape around the line connecting the rotation center of the light source means and said rotary shaft is symmetrical, the disc Rotational axis of the unit and the plane substrate
It is characterized in that the spring-like member integrated with the V-shaped block is used for temporarily fixing the orientation .

The invention of claim 2 is the same as the invention of claim 1.
The disk further has a grid for detecting the origin signal,
Disk hub and the rotary shaft, which are fixed to the disk hub.
Is screwed from the arrangement direction of the grid for detecting the origin signal.
It is characterized by

A rotational displacement information detecting device according to a third aspect of the invention.
Is guided to the radiation grating provided on the disc and the grating of the disk disposed opposite the planar substrate to relatively rotate the light beam from the light source means, receiving the light modulated by the radiation grid and該格element In a rotational displacement information detecting device for receiving a light flux by a light receiving means and detecting relative rotational displacement information between the disk and the plane substrate by using a signal from the light receiving means, the light source means, the plane substrate and the light receiving means. A main unit for fixedly disposing the means and a disc unit for fixedly disposing the disc are separately configured, and a disc hub is fixed to the disc, and the disc unit and the rotary shaft of the main unit. Positioning on a plane orthogonal to V is centered on a straight line connecting the light source means and the center of rotation of the rotation axis.
The V-shaped block is attached to the main body unit so that the slopes forming the letter are symmetrical, and the side surface of the rotary shaft is pressed in the V-block direction when the disk unit is connected to the rotary shaft. It is characterized by being screwed.

The invention of claim 4 resides in the invention of claim 3.
The disk has a grid for origin signal detection,
It is characterized in that the screwing is performed in two directions which are line-symmetric with respect to a straight line connecting the center of rotation of the disk and the position of the grid for detecting the origin signal.

[0029]

[0030]

[0031]

[0032]

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a main part of a first embodiment of a rotational displacement information detecting device of the present invention.

This embodiment shows a so-called built-in type rotary encoder (encoder), in which the encoder itself does not have a rotation axis, and a measurer (user) directly attaches to a rotation axis such as a motor as an object to be detected. The disk 3 is mounted.

In the figure, 101 is a disk unit, which is a disk (main scale) 3 and the disk 3
And a disk hub 8 to which is fixed. Disk 3
250 for example in a donut-shaped area with a radius of 8-12 mm
Radiation grating 4 consisting of about 0 transparent and opaque slits
And an amplitude grating 4Z for detecting the origin position is recorded on a circumference different from that of the radiation grating 4 to form a main scale. The disk hub 8 is screwed to the dummy rotary shaft 7 during assembly. The dummy rotary shaft 7 is removed from the disk hub 8 after the assembly is completed.

Reference numeral 1 is an LED as a light emitting element. Reference numeral 2 denotes a collimator lens, which makes the light flux from the LED 1 incident on the main scale 3 as a parallel light flux. LED1
The collimator lens 2 constitutes an element of the light source means. Reference numeral 5 denotes a flat substrate (index scale) which is arranged to face the main scale 3 and has a radial amplitude grating (grating) 5A on the surface thereof, which is spatially shifted in phase by 90 degrees from each other at the same pitch as the radiation grating 4. , 5B are provided. The amplitude gratings 5A and 5B perform optical modulation so that the transmitted light becomes maximum when it overlaps with the radiation grating 4 of the main scale 3 and becomes minimum when overlapped with a 1/2 pitch shift. The light beam which has passed through the amplitude gratings 5A and 5B is received by the light receiving means 6 which will be described later to obtain an incremental signal (A phase, B phase).

A radial amplitude grating (grating) 5Z having the same pattern as the amplitude grating 4Z for obtaining the origin position signal (Z-phase signal) of the rotation of the object to be detected is provided on the plane substrate 5. When the amplitude grating 4Z and the amplitude grating 5Z completely coincide with each other, the light is modulated so that the transmitted light becomes maximum, and the amplitude grating 4Z
Optical modulation is performed so that the transmitted light becomes smaller when the Z and the amplitude grating 5Z deviate by more than the grating width, and the origin position (Z
Phase) signal.

A sensor (light receiving means) 6 has three sensors 6A, 6B and 6Z for detecting the A phase signal, the B phase signal and the Z phase signal. The sensor 6 is provided on the sensor substrate 9. A base member 11 mounts and fixes the respective elements 1, 2, 5, 6, 9 and each of these elements constitutes one element of the main body unit 102.
In this embodiment, the main unit 102 and the disk unit 101 are provided.

Next, a method of detecting rotation information of the rotary shaft in the encoder of this embodiment will be described.

In the present embodiment, the collimator lens 2 collimates the light flux from the LED 1 into parallel light, and the emission grating 4 for detecting the incremental signals (A phase, B phase) of the main scale 3 and the amplitude grating for detecting the origin signal (Z phase). Illuminating 4Z. The sensor 6A receives the luminous flux transmitted through the radiation grating 4 and the amplitude grating 5A to obtain an A-phase signal, and the sensor 6B receives the luminous flux transmitted through the radiation grating 4 and the amplitude grating 5B to obtain a B-phase signal. The light flux transmitted through 4Z and the amplitude grating 5Z is received by the sensor 6Z to obtain a Z-phase signal.

That is, in the sensors 6A and 6B, the main scale 3 and the index scale (planar substrate) 5 are the radiation grating 4
When the (amplitude gratings 5A, 5B) are moved relative to each other by one pitch, a change in the light amount for one cycle is detected, and incremental signals (A phase, B phase) whose phases are shifted by 90 degrees are output.
For example, the analog signals from the sensors 6A and 6B are binarized into A-phase signals and B-phase signals. The A-phase signal and the B-phase signal are counted to obtain the rotational position information of the rotary shaft. For example, when the phase A signal changes from L to H, 1 is added to the count value if the state of the B phase signal is H, and 1 is subtracted from the count value if the state of the B phase signal is L. Looking for.

The sensor 6Z outputs several small ridge-shaped waveforms on both sides of one large ridge-shaped waveform as the main scale 3 rotates in a relative manner. The full width at half maximum of the large mountain-shaped waveform substantially coincides with the rotation corresponding to the width of the slits of the amplitude grating 4Z and the amplitude grating 5Z. Therefore, this signal is binarized at 1/2 level to obtain a 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, in order to count the incremental signals (A phase, B phase) with reference to the origin signal (Z phase), the incremental signal (A phase signal) and the origin signal (Z phase) are synchronized. . That is, the rising and falling timings of the Z-phase signal and the rising and falling timings of the A-phase signal are completely matched. Since the Z-phase signal width is substantially determined by the rotation amount of the slit width of the amplitude grating 5Z, the slit width of the amplitude grating 5Z is matched with the rotation amount of one pitch of the radial grating 4 and the width of the Z-phase signal is set to A. The width of the H level of the phase signal is doubled. Furthermore, by appropriately setting the recording positions of the radial gratings 4, 5A, 5B and the amplitude gratings 4Z, 5Z, the width of the H level of the rectangular wave signal of the Z phase signal is changed to the H level of the rectangular wave signal of the A phase signal. One is included completely (in the center). After that, the A-phase signal and the Z-phase signal are logically processed (AN
By performing D), the origin signal (Z phase) completely synchronized with the A phase is output.

Next, the features of assembling the disk unit 101 and the main unit 102 and mounting the disk unit 101 on the rotary shaft of the object to be measured in this embodiment will be described.

In this embodiment, the disk unit 101 and the main body unit 102 are fixed by the V-shaped block 10 during product packaging. In the built-in encoder as in this embodiment, the measurer (user) connects the disk unit 101 and the rotation axis of the object to be measured. In order to synchronize the A-phase signal and the Z-phase signal of the encoder, it is necessary to suppress the eccentricity of the disk unit 101 and the x-axis component of the positional displacement of the plane substrate 5. The deviation in the x-axis direction at this time needs to be about 21 μm or less, and this x-axis azimuth deviation is the tightest value in all directions.

Next, a method of assembling the built-in encoder of this embodiment will be described.

First, the disk hub 8 is attached to the dummy rotary shaft 7 and the eccentricity of the disk 3 is adjusted. At this time, the disk hub 8 is screwed to the dummy rotary shaft 7. Figure 2
As shown in (A), the V-shaped block 10 is attached to the base member 11.
Is fixed, and the dummy rotary shaft 7 attached to the disk unit 101 is butted against the V-shaped wall of the V-shaped block 10 to be positioned and fixed. At this time, the V-shaped block 1 is centered on the straight line connecting the rotation center of the dummy rotation shaft 7 and the LED 1.
The slopes forming the V-shape of 0 are symmetrical.

At this time, the disk hub 8 is shown in FIG.
As shown in FIG. 5, the V-shaped block 10 is also fixed in the Z direction by the springy portion 10B. At this time, it is important that the disk 3 be in the rotation phase when the Z phase is detected.
In this state, the sensor 6 and the sensor substrate 9 on which the flat substrate 5 provided with the amplitude gratings 5A, 5B, and 5Z is mounted, x,
Position adjustment in the y and z directions is performed. The position adjusting mechanism of the sensor substrate 9 is not shown. After the assembly of the dummy rotary shaft 7 is completed, the dummy rotary shaft 7 is removed from the disk hub 8 and delivered to the measurer (user).

Next, the case where the measurer (user) attaches the encoder to the rotary shaft of the object to be measured and uses it will be described.

Here, as shown in FIG. 3, it is assumed that the rotary shaft 17 attached by the user has a shaft diameter different from the shaft diameter of the dummy rotary shaft 7 used when assembling the encoder. When the user installs the encoder, the user attaches the disk hub 8 to the rotary shaft 17 and installs the encoder main unit 10
The rotary shaft 17 is abutted against the V-shaped block 10 fixed to 2 to position the disk unit 101 and the main body unit 102 relative to each other. However, even if the shaft diameter changes temporarily, as shown in FIG. 10 V-shape in the Z-phase detection direction (y
Direction), the positional deviation of the rotation center of the disk 3 due to the change in the shaft diameter occurs only in the y direction and does not affect the synchronization of the A phase and the Z phase.

As shown in FIG. 4A, the disc hub 8 and the rotary shaft 17 are connected to each other by the Z-phase pattern 4Z and the disc 3.
Since it is performed from the direction connecting the centers of the disk units 101, similarly, the eccentricity at the time of mounting the disk unit 101 only affects the y direction, and does not affect the synchronization of the A phase and the Z phase. Thus, in the present embodiment, the disk unit 101 stably synchronizes the A phase and the Z phase without any positional deviation in the x direction when the rotational phase is detected in the Z phase.

Regarding the displacement in the y direction, the A phase, B phase and Z
Since the signals of the phases should not be confused, for example, the radiation grating 4
If the track width is 200 μm, a deviation of up to 100 μm is allowed. However, when the rotational phase of the disk 3 is at the Z-phase detection position, it is advantageous that the shift in the y-direction is suppressed in terms of synchronization between the A-phase and the Z-phase.

As shown in FIG. 5, when the V-shaped angle of the V-shaped block 10 is θ, the displacement h of the disk unit 101 in the y direction is h = (D ₁ −D ₀ ) / sin θ. Since the V-shaped angle θ of the general V-shaped block 10 is 45 degrees, in the case of the V-shaped block of this angle,
(D ₁ −D ₀ ) is allowed up to about 70 μm.

In the case of the present embodiment, the V-shaped angle is set to 120 degrees in order to relax the allowable amount of displacement in the y direction. Table 1 shows the relationship between the V-shaped angle and the deviation in the y direction due to the change in the shaft diameter (converted by the ratio based on the V-shaped angle of 90 degrees). As the V-angle increases, the y-direction shift decreases. However, if the V-shaped angle becomes large, the positioning action due to the V-shaped deteriorates, and there is a possibility that a displacement in the x direction, which should be originally pressed, may occur. Therefore, in this embodiment, the V-shaped angle of the V-shaped block 10 is set around 100 ° to 130 °.

[0055]

[Table 1] As shown in FIG. 4A, in this embodiment, the disc hub 8 and the rotary shaft 17 are connected to each other by the Z-phase pattern 4Z and the disc 3.
The screw 41 is screwed from the direction facing the V-shaped block 10 along the straight line connecting the centers of the two. As a result, the displacement of the abutment of the V-shaped block 10 due to the change in the shaft diameter and the displacement due to the eccentricity that occurs when the disk hub 8 and the rotating shaft 17 are connected become the detection position of the Z-phase rotational phase of the rotating shaft. In this case, the influence is exerted in the opposite direction, so that the allowable amount of shaft diameter change is further reduced.

Specifically, the positional deviation in the y direction at the Z phase detection position between the disk 3 and the flat substrate 5 is h = (D ₁ -D ₀ ) × (1 / sin θ-1).

If the allowable displacement of the disk unit 101 in the y direction is 100 μm, the change in shaft diameter is 0.5 m.
More than m is allowed, which is generally impossible. As a result, the signal quality of the encoder is affected only by the rotation accuracy of the rotary shaft installed by the user. Regarding the connection between the disk hub 8 and the rotary shaft 17, the rotary shaft 1
7 may be pressed against the wall surface of the disk hub 8 on the V-shaped block 10 side, for example, as shown in FIG.
As shown in FIG. 5, the same effect can be obtained by fixing the two screws 42 and 43 facing the V-shaped block 10.

Positioning in the Z direction is performed by abutting the disk hub 8 against the portion 10A of the V-shaped block 10 and pressing it with the spring-like portion 10B of the V-shaped block 10. In the Z direction, it is necessary to suppress the positional accuracy of the upper surface of the disk 3 and the flat substrate 5 to about ± 30 μm.
If the error that occurs when the encoder is assembled is suppressed to ± 15 μm, the disk hub 8 butts against the portion 10A of the V-shaped block 10 sufficiently guarantees the positional accuracy of the upper surface of the disk 3 and the flat substrate 5 of ± 15 μm. Value. Further, as shown in FIG. 2B, the abutting portion, the portion 10A, and the spring portion 10B are integrated to form the V-shaped block 10, thereby reducing the number of parts.

[0059]

As described above, according to the present invention, the main body unit having the light source means, the light receiving means (sensor), the index scale (planar substrate) and the like is separated from the disk unit having the disk (main scale). By using a V-shaped block in which the disk unit and the main body unit are appropriately configured when configured as a body, positioning in the rotation axis direction and / or positioning on a plane perpendicular to the rotation axis can be performed with high accuracy. It is possible to achieve a rotational displacement information detection device suitable for an embedded encoder that can be performed and that can detect rotational displacement information with high accuracy with little synchronization deviation between the A-phase signal and the Z-phase signal.

In addition, according to the present invention, an encoder of built-in type in which the A-phase signal and the Z-phase signal are less likely to be out of synchronization by properly screwing the disk hub to which the disk is fixed and the rotary shaft. A suitable rotational displacement information detecting device, and a rotational displacement information detecting device suitable for an embedded type encoder that accurately positions a disk unit and a main body unit with a V-shaped block having an appropriate V-shaped angle are provided. Can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of a first embodiment of the present invention.

FIG. 2 is an enlarged explanatory view of a part of FIG.

FIG. 3 is an explanatory diagram showing an effect of a V-shaped block according to the present invention.

FIG. 4 is an explanatory view showing an effect of a screwing direction of a disk hub and a rotating shaft according to the present invention.

FIG. 5 is an explanatory diagram showing a positional deviation h in the y direction due to a change in the diameter of a rotating shaft according to the present invention.

FIG. 6 is a schematic view of a main part of a conventional rotary encoder.

FIG. 7 is an explanatory view showing a fitting gap when the hub is attached to the shaft.

FIG. 8 is an explanatory view showing a disc eccentricity and a positional displacement of a flat substrate.

[Explanation of symbols]

1 Light emitting element 2 Collimator lens 3 discs (main scale) 4,4Z radiation grating 5 Flat board (index scale) 5A, 5B, 5Z Radiation grating 6,6A, 6B, 6Z Light receiving element 7 Dummy rotation axis 8 disk hub 9 sensor board 10 V block 17 rotation axis

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-193022 (JP, A) JP-A-59-205676 (JP, A) JP-A-6-3163 (JP, A) Sankaihei 1- 17418 (JP, U) German patent application publication 3740744 (DE, A 1) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01D 5/00-5/62

Claims (4)

(57) [Claims] 1. A light beam from a light source means is guided to a radiation grating provided on a disk which rotates relative to the radiation grating and a grating on a plane substrate which is arranged to face the disk, and the light modulation is performed by the radiation grating and the grating. A light receiving means receives the received light beam by a light receiving means, and detects a relative rotational displacement information between the disk and the plane substrate by using a signal from the light receiving means. A main unit for fixedly disposing the substrate and the light receiving means and a disc unit for fixedly disposing the disc are separately configured, and the disc unit and the main unit are directly connected to the rotary shaft.
Positioning on the intersecting plane is performed by a V-shaped block attached to the main body unit so that a slope forming a V-shape is symmetrical with respect to a straight line connecting the light source means and the rotation center of the rotation shaft. At the same time, the rotational displacement information detecting device is characterized in that the disk unit and the planar substrate are temporarily fixed in the rotational axis direction by a spring member integrated with the V-shaped block. 2. The disk further comprises a case for detecting an origin signal.
Has a child, is fixed to the disc hub, and
The rotation axis is from the arrangement direction of the grid for detecting the origin signal.
The rotational displacement information detection device according to claim 1, wherein the rotational displacement information detection device is screwed . 3. A light beam from a light source means is guided to a radiation grating provided on a rotating disk and a grating on a flat substrate arranged opposite to the disk, and the light is modulated by the radiation grating and the grating. A light receiving means receives the received light beam by a light receiving means, and detects a relative rotational displacement information between the disk and the plane substrate by using a signal from the light receiving means. A main body unit fixedly arranging the substrate and the light receiving means and a disc unit fixedly arranging the disc are separately configured, and a disc hub is fixed to the disc, and the disc unit and the main body unit are A plane orthogonal to the rotation axis
The surface is positioned by a V-shaped block attached to the main body unit so that a slope forming a V-shape is symmetrical with respect to a straight line connecting the light source means and the center of rotation of the rotary shaft. A rotational displacement information detecting device characterized in that, when the disk unit is connected to a rotary shaft, a side surface of the rotary shaft is pressed in the V-block direction and screwed. Wherein said disk has a grating for detecting an origin signal, wherein the screw is a line-symmetrical to a straight line connecting the center of rotation and grating for raw point signal detection of the disk 2
The rotational displacement information detection device according to claim 3 , wherein the rotational displacement information detection device is performed from the direction.