JPH1062206A - Rotational displacement information detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly accurately execute positioning in the rotary shaft direction of a disk unit and on a plane rectangular to the rotary shaft direction at the time of positioning the amplitude grating of a disk and that of a plane substrate. SOLUTION: A block member 10 for holding the disk unit 101 on the plane rectangular to the rotary shaft direction of the unit 101 is arranged on a body unit 102 so as to be freely moved to the rotary shaft direction of the unit 101, a position regulating means 10D in the block member 10 regulates the position of the unit 101 on a straight line connecting the center of a rotary shaft to a light source means 2, and a temporary fixing means 10C in the member 10 temporarily fixes the unit 101 in the position regulated state.

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 luminous flux onto a radiation grating of a main scale and a radiation grating of an index scale that relatively rotate and move, and obtains a phase or a phase obtained therefrom. The present invention is suitable for a rotary encoder that detects intensity-modulated signal light to detect relative rotational displacement information between the main scale and the index scale and rotational displacement information such as the origin position.

In particular, a so-called main unit having light source means, light receiving means and an index scale and a disk unit having a main scale are provided separately.
It relates to a built-in type rotary encoder.

[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. 9 shows an outline of a rotary encoder having an origin detection 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 periodically changes in accordance with the degree of coincidence between the two patterns due to the movement of the main scale 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 and an electric sinusoidal incremental signal (A phase signal,
A sine signal is further converted by a binarization circuit to generate a rectangular wave incremental signal (A-phase signal,
B-phase signal). Thus, the rotational displacement information of the rotating shaft 7 is detected.

The rotary encoder detects the origin information as follows. That is, a transparent / non-transmissive (reflective / non-reflective) origin pattern 4Z is recorded on a relatively moving disk (main scale) 3, and the same origin pattern 5Z is recorded on a fixed flat substrate (index scale) 5. After that, the two are superposed at a predetermined interval (gap), and then both are irradiated with a parallel light beam from the LED 1 via 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 origin signal is converted by a binarizing circuit to obtain a rectangular wave origin signal.

As described above, the rotary encoder having the origin detecting function utilizes both the principle of detecting the incremental signal and the principle of detecting the origin signal by utilizing the modulation effect of the amount of transmitted light due to the change in the degree of overlap between the main scale 3 and the index scale 5. I have.

[0009]

In recent years, with the rotary encoder having the above-described configuration, with the increase in accuracy and miniaturization of a machine tool or a measuring machine to be mounted, a high resolution is required for detecting displacement information. There is a demand for miniaturization and miniaturization. In particular, the demand for miniaturization is not limited to the size of the encoder main 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.

[0010] Specifically, a so-called "built-in type" rotary encoder is used in which an encoder has a disk mounted directly on a rotary shaft of a motor or the like without independently having a rotary shaft, and further mounts an encoder body on a motor housing. Has been requested. This "built-in type" rotary encoder generally has a two-part structure in which a disk unit and an encoder body (detection head) unit are spatially separated.

When a user (measurer) attaches the rotary encoder having such a configuration to a motor or the like, a process of fixing a disk (main scale) to a rotating shaft of the motor and a process of fixing an encoder body to a motor housing are performed. Will be needed.

In this case, the incremental signal (A-phase signal, B-phase signal) and the origin signal (Z
(1) that the radial grating pattern tracks on the disk are not eccentric during rotation of the motor shaft, (2) the radial grating pattern tracks on the disk and the flat substrate (index scale)
It is an indispensable condition that the upper radial grating pattern track overlaps exactly.

However, when the disk is actually mounted on the rotating shaft of the motor, the center of rotation of the motor shaft and the center of the radial grating pattern track on the disk are shifted due to an error in the dimensions of the parts. There is a problem that the track and the radiation grating pattern on the flat substrate in the encoder main body are shifted due to an error in a mounting portion between the motor housing and the encoder main body.

Further, as a general tendency, as the encoder disk becomes smaller (small diameter) and has higher resolution, the pitch of the radiation grating pattern on the disk and the radiation grating pattern on the flat substrate become finer, and the relative positional shift occurs. (Azimuth shift between the gratings) has a disadvantage that the signal output tends to deteriorate.

For example, as shown in FIG.
A disk 3 on which 2500 radiation gratings 4 are recorded in a 2 mm donut-shaped area is bonded to a hub 6 with a φ6 hole to form a disk unit. At this time, it is assumed that the radiation center of the radiation grating pattern 4 is adhered to the center of the hole 8a of the perforated hub 8 with an error on the order of several microns and the eccentricity is minimized. This disk unit and the shaft 7 of the motor are inserted in a relationship of fitting of H7 of φ6 mm,
The disk unit is fastened with a set screw 20 from the side surface of the hub 8.

In such a connection state, when the hole 8a of the hub 8 and the shaft 7 are fitted with the φ7 H7, a maximum of 35
Eccentricity up to 17.5μ due to micron gap
m. Actually, the shaft 7 of the motor also has a fitting relationship with the inner ring of the bearing built into the motor.
The eccentricity of the disk pattern after being attached to the shaft 7 of the motor also has a possibility of eccentricity of the same degree or more with respect to the rotation center.
m.

Furthermore, when the encoder main body is mounted on the motor housing, it is practically difficult to provide a high-precision fitting contact portion on the motor housing regardless of the encoder main body. If the positioning and fixing are performed in a medium-precision contact relationship, a gap of about 100 μm is generated.
There is a possibility that the azimuth or Y azimuth is shifted.

Here, as shown in FIG.
Are eccentric in the X direction by 35 μm, and the encoder body is −50 μm in the X direction (specifically, the plane substrate 5 is −50 μm).
(50 μm) is considered.

Radiation grating 4 on disk 3 has a radius of 10 mm
And the grating pitch is 25 μm. It is also assumed that the amplitude grating 4Z for detecting the origin on the disk 3 is recorded at a radius of 6 to 8 mm. As a result, as a sum of the eccentricity of the disk 3 and the error of the mounting position of the encoder main body, the disk 3 and the plane substrate 5 are shifted by 85 μm in the X direction.

In this case, the A-phase signal has a disk radius of 10 m.
m, the phase A detection timing is 85
/25=3.4 cycles. Further, assuming that the Z-phase signal is detected at a disk radius of 7 mm, the detection timing of the Z-phase is shifted by 85/25 × 7/10 = 2.38 cycles. In this case, the A-phase signal and the Z-phase signal are relatively 3.4-
There is a shift of 2.38 = 1.02 cycles (however, the A-phase rectangular wave signal is used as a reference for one cycle). Thus, the waveform output of the Z-phase signal is shifted by ± 1.02 cycles from the waveform output of the A-phase due to the relative X-azimuth deviation of 85 μm between the encoder body and the disk 3.

In the above-described example, it is difficult to synchronize the Z-phase signal and the A-phase signal with a logic circuit.
This is because if the relative mounting error between the encoder body and the disk 3 is proportional to the relative phase shift between the A-phase signal and the Z-phase signal, it must be kept within 21 μm. Moreover, since there is a possibility that an error of 35 μm may occur when the disk 3 is mounted on the shaft 7, it is impossible to correctly obtain A-phase and Z-phase signal outputs from the encoder.

As described above, when the size of the encoder disk is small (small diameter) and high in resolution, the pitch of the radiation grating on the disk 3 and the pitch of the radiation grating on the plane substrate 5 become fine, and the relative positional deviation (grating and Due to the azimuth shift between the gratings), the signal output is apt to decrease, and the built-in type rotary encoder is extremely difficult to be built, and its practical use has been very difficult.

According to the present invention, when a disk unit having a disk (main scale) and the like and a main unit having a light source means, a light receiving means, a flat substrate (index scale) and the like are constituted separately, When positioning the amplitude grating and the amplitude grating of the flat substrate, a block member provided in the main body unit so as to be movable in the rotation axis direction of the disk unit is used to determine the position of the disk unit in the rotation axis direction and the rotation axis direction. It is suitable for a built-in type encoder that can perform high-precision positioning on a plane that is perpendicular to the axis and that can detect rotation displacement information with high accuracy with little synchronization deviation between the A-phase signal and the Z-phase signal. It is an object to provide a rotational displacement information detecting device.

[0024]

SUMMARY OF THE INVENTION A rotational displacement information detecting apparatus according to the present invention comprises: [1]: a radiation grating on a disk which relatively rotates a light beam from a light source means and a radiation grating on a flat substrate opposed to the disk. The light beam guided to the radiation grating and the light beam modulated by the two radiation gratings is received by the light receiving means, and the information from the light receiving means is used to detect relative rotational displacement information between the disk and the flat substrate. The rotational displacement information detecting device includes a main unit including the light source unit, the flat substrate, and the light receiving unit, and a rotatable disk unit including the disk. A block member held on a plane perpendicular to the direction and fixed to the main body unit is provided movably in a rotation axis direction of the disk unit; Positioning means for defining the position of the disk unit on a straight line connecting the center of the rotation axis and the light source means to the disk unit, and temporary fixing means for temporarily fixing the disk unit whose position is defined by the position specifying means. It is characterized by that.

In particular, in the rotational displacement information detecting device according to the above [1], [1-2]: The main unit is provided with guide means for guiding the block member along the direction of the rotational axis of the disk unit. [1-3]: the block member is attached to a holding portion for holding the disk unit on a plane perpendicular to the rotation axis direction of the disk unit and to the main unit so as to be movable in the rotation axis direction of the disk unit. [1-4]: the position defining means has a V-shaped wall forming a V around a straight line connecting the center of the rotation axis of the disk unit and the light source means, The position of the disk unit is defined by using the V-shaped wall. [1-5]: The position defining means is centered on a straight line connecting the center of the rotation axis of the disk unit and the light source means. Is formed in a concave portion having a V-shaped wall forming a V-shape, and the position of the disk unit is defined by the V-shaped wall of the concave portion. [1-7]: The temporary fixing means is formed on a spring member having elasticity in the direction, and the disk unit is temporarily fixed by using the elasticity of the spring member. Formed on a resilient spring member and provided integrally with the block member.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The rotation displacement information detecting device of the present invention will be described below in more detail with reference to an embodiment shown in the accompanying drawings.

In the accompanying drawings, FIG. 1 is a schematic view of a principal part of a rotational displacement information detecting device according to the present invention, FIG. 2 is an enlarged plan view of the rotational displacement information detecting device with the sensor substrate removed from FIG. 1, and FIG. FIG. 4 is an explanatory view showing a state in which the recess of the member receives the disk unit, FIG. 4 is a plan view of the block member, and FIG.
FIG. 6 is a front view of the block member, FIG. 6 is an explanatory view of a state in which the position of the disk unit is defined by a concave portion of the block member, FIG. 7 is an explanatory view of a state in which the disk unit is screwed to the block member, and FIG. FIG. 9 is an explanatory diagram for explaining a positional shift in the Y direction at the origin detection position between the disk and the flat substrate due to a change.

The rotational displacement information detecting device according to the present embodiment is a so-called built-in type rotary encoder (hereinafter abbreviated as an encoder), and comprises a disk unit 101 and a main unit 102 as shown in FIG. It is provided as a constituent unit.

The encoder itself does not have a rotating shaft, and as will be described later, a user (measurer) mounts a disk unit 101 described later directly to a rotating shaft 17 such as a motor as an object to be detected. Has become.

As shown in FIG. 1, the disk unit 101 includes a disk (main scale) 3 and the disk 3
And a disk hub 8 integrally fixed to the disk hub 8.

The disk 3 has, for example, a radius of 8 to 12 mm.
In the donut-shaped area, a radial amplitude grating (radiation grating) 4 composed of about 2500 transmission and non-transmission slits and an amplitude grating 4Z for detecting the origin position are recorded on a circumference different from the amplitude grating 4 respectively. This forms a main scale (see FIG. 6).

The disk hub 8 fixed integrally with the disk 3 has a pair of upper and lower flange portions 8A, and has a hole 8B with a downward opening formed therein (see FIG. 3). At the time of assembly, a 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.
It is being removed more.

As shown in FIG. 1, the main unit 102 comprises an LED (light emitting element) 1, a collimator lens 2, a flat substrate (index scale) 5, a sensor (light receiving element) 6, a sensor substrate 9, and a base member 15. ing. The LED 1 and the collimator lens 2 constitute one element of the light source means.
Illuminates the disk 3 with the light beam from the LED 1 as a parallel light beam.

The flat substrate 5 is arranged to face the disk 3 of the disk unit 101, and amplitude gratings 5A, 5B, 5Z described later are recorded on the surface thereof to form an index scale. On the plane of the plane substrate 5, the amplitude grating 4 of the disk 3 and the
Radial amplitude gratings (radiation gratings) 5A and 5B shifted by degrees are recorded. These amplitude gratings 5A and 5B transmit the light flux from the LED 1 so that the transmitted light is maximized when overlapping with the amplitude grating 4 of the disk 3 and minimized when overlapping with a １ ／ pitch shift. Modulate.
Then, the sensor 6 (described later) receives the light beam that has passed through the amplitude gratings 5A and 5B, so that an incremental signal (A-phase signal and B-phase signal) is obtained.

In addition to the amplitude gratings 5A and 5B described above, an amplitude grating 5Z for obtaining a rotation origin position signal (Z-phase signal) of the detected object is recorded on the surface of the flat substrate 5. I have. This amplitude grating 5Z is the same as the amplitude grating 4 on the disk 3.
The light flux from the LED 1 is light-modulated so that the transmitted light is reduced when it is displaced from Z by a grating width or more. Then, a light beam that has passed through the amplitude grating 5Z is received by a sensor 6, which will be described later, so that an origin position signal (Z-phase signal) of the rotating shaft is obtained.

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

The base member 15 has the above-described L.
ED1, collimator lens 2, flat substrate 5, sensor 6
The sensor substrate 9 is fixed at a predetermined position.

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 according to the present 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 main scale 3 and an origin signal (Z-phase signal). ) Illuminate the amplitude grating 4Z for detection.

Thus, the light beam transmitted through the amplitude grating 4 and the amplitude grating 5A is received by the sensor 6A to obtain an A-phase signal.
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 beam transmitted through Z is received by the sensor 6Z to obtain a Z signal.

That is, the sensors 6A and 6B
When the substrate and the plane substrate 5 relatively move by one pitch of the amplitude grating 4, a change in the amount of light in one cycle is detected, and the phase is 9
An incremental signal (A-phase signal, B-phase signal) shifted by 0 degrees 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 “ If L "," 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 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, in order to count incremental signals (A-phase signal, B-phase signal) based on the origin signal (Z-phase signal), the incremental signal (A-phase signal) and the origin signal (Z-phase signal) are counted. Synchronized. In other words, the rising and falling timings of the Z-phase signal completely match the rising and falling timings of the A-phase signal. In detail, as described above, since the signal width of the Z-phase signal is substantially determined by the rotation of the slit width of the amplitude grating 5Z, the slit width of the amplitude grating 5Z is set to one pitch of the amplitude grating 4 as described above. To the rotation equivalent of
The width of the phase signal is twice the width of the "H" level of the A-phase signal. Then, the amplitude grating 4 on the disk 3 and the flat substrate 5
Upper amplitude gratings 5A and 5B, on disk 3 and flat substrate 5
By setting the recording position of each of the upper amplitude gratings 4Z and 5Z to an appropriate position, 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 width. Thereafter, the A-phase signal and the Z-phase signal are logically processed (AN
D), an origin signal (Z-phase signal) completely synchronized with the A-phase signal is obtained.

As described above, the encoder for detecting the two types (the incremental signal and the origin signal) is formed by integrally fixing the disk 3 to the disk hub 8 to simplify the assembly. 101, and further comprises an LED 1, a collimator lens 2, a plane substrate 5, a sensor 6, and a sensor substrate 9 as a base member 15.
To form a main unit 102. 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 furthermore,
The amplitude gratings 5A, 5B and the amplitude grating 5Z for detecting the origin are recorded in parallel on the same plane substrate 5, and the sensors 6A, 6B, 6Z for detecting the incremental signal and the origin signal are arranged in parallel on the same sensor substrate 9. It is arranged so that it is arranged.

In the encoder of the present embodiment configured as described above, the disk unit 101 and the main unit 102 are fixed using a block member 10 described later when packing the product, as shown in FIG.

At this time, in order to synchronize the A-phase signal and the Z-phase signal detected by the encoder, the eccentricity of the disk (main scale) 3 and
It is necessary to suppress the X-axis component of the positional deviation of the planar substrate (index scale) 5. Here, for example, when the disk 3 on which 2500 radiation gratings 4 are recorded in the above-described donut-shaped area having a radius of 8 to 12 mm is used as a main scale, X It is necessary to suppress the misalignment of the direction to 21 μm or less,
This deviation is the sharpest value in all directions.

However, by assembling the disk unit 101 and the main unit 102 using the block member 10, the deviation in the X direction can be suppressed to a value that does not affect the detection accuracy.

As shown in FIGS. 4 and 5, the block member 10 is formed to have a substantially L-shaped side surface, and a base 10A extending in the rotation axis direction (Z direction) of the disk unit 101; A holding portion 10B extending from the base 10A in a direction (Y direction) orthogonal to the direction of the rotation axis of the disk unit 101, and is provided integrally with the holding portion 10B to provide elasticity in the direction of the rotation axis (Z direction) of the disk unit 101. A pair of spring members 10 as temporary fixing means having
C. In the center of the tip of the holding portion 10B, a concave portion 10D is formed as a position defining means having a V-shaped wall 10E for defining the position of the disk hub 8 of the disk unit 101.

Hereinafter, an assembling method for assembling the disk unit 101 and the main unit 102 using the block member 10 will be described.

First, the dummy rotary shaft 7 is connected to the disk hub 8.
To adjust the eccentricity of the disk 3. At this time,
Since the disk hub 8 is screwed to the dummy rotating shaft 7, the screwing is released, and then the main unit 1
The holding portion 10B of the block member 10 and the spring member 10C are inserted into the insertion opening 15A opened in the base member 15 of No. 02.

As a result, the dummy rotary shaft 7 of the disk hub 8 enters the concave portion 10C of the holding portion 10B and the V-shaped wall 1
0E (see FIG. 2), and a spring member 10C enters between a pair of flange portions 8A of the disk hub 8 to clamp the lower flange portion 8A together with the holding portion 10B, thereby causing the disk hub 8 to become a block member. It is held and fixed by 10 (see FIG. 1).

Thus, the insertion opening 15A of the base member 15
As shown in FIG. 1, the block member 10 inserted in
The screw 21 is screwed into the base 10A and the base member 15 to be fixed to the main unit 102.
Or one of the screw holes 10H of the base member 15,
By forming the hole 15H in the elongated hole (the base 10A in this embodiment), the disk unit 101 can be moved in the Z direction while being held and fixed.

That is, the block member 10 is connected to the main unit 1
02 and a base 10 formed in a long hole.
A or one of the screw holes 10 of the base member 15
H and 15H constitute a position adjusting mechanism S that enables the block member 10 to move together with the disk unit 101 in the Z direction.

The base member 15 is formed with a guide recess G as guide means for guiding the block member 10 along the Z direction. This guide recess G
Is formed at an outer peripheral portion facing the base 10A of the block member 10, and has a flat surface 11 parallel to the X direction and a guide surface 22 parallel to the Y direction, and extends in the Z direction.
In the guide recess G, both the flat surface 11 and the guide surface 22 are subjected to high-precision flat processing, and the flat surface 11 is provided with the back surface of the base 10A of the guide member 10 and the guide surface 22 is provided with one side surface of the guide member 10. Are brought into contact with each other, and the guide member 10 is moved in the Z direction in this state, whereby the disk unit 101 can be moved in the Z direction while preventing the deflection of the upper surface of the disk 3.

Thus, the amplitude gratings 4, 4 of the disk 3
The positioning of the amplitude gratings 5A, 5B, 5Z of Z and the plane substrate in the Z direction can be performed easily and with high accuracy.

Next, as shown in FIG. 3, the dummy rotating shaft 7 to which the disk unit 101 is attached is connected to the block member 1.
Abutting against the V-shaped wall 10E of the concave portion 10D of No. 0 to position and fix it. At this time, the rotation center of the dummy rotation shaft 7 and LE
Block member 1 centering on a straight line in the Y direction connecting D1
The V-shaped wall 10E of 0 is symmetrical (see FIG. 6). At this time, it is important that the disk 3 is set to the rotation phase at the time of detection of the Z-phase signal.

Thereafter, the X and Y directions of the sensor substrate 9 on which the sensor 6 and the flat substrate 5 are mounted are adjusted by a position adjusting mechanism (not shown), whereby the disk unit 101 is assembled to the main unit 102. Is completed.

After the assembly of the disk unit 101 into the main unit 102 is completed, the dummy rotary shaft 7 is removed from the disk hub 8 and delivered to the user.

Next, a case where the user mounts the encoder on the connecting shaft of the object to be detected and uses the encoder will be described with reference to FIGS. It is assumed that the connecting shaft 17 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.

First, the user attaches the disk hub 8 to the connecting shaft 17 when assembling the encoder, and as shown in FIG. 6, the V-shaped wall 10E of the concave portion 10D of the block member 10 fixed to the main unit 102. The positioning is performed by abutting the connecting shaft 17 against the.

At this time, even if the shaft diameter changes, if the block member 10 is installed in a state where the V-shaped wall 10E is opposed to the amplitude grating 4Z for detecting the origin position, the disk 3 caused by the change in the shaft diameter can be obtained. Is caused only in the Y direction, and does not affect the synchronization of the A-phase signal and the Z-phase signal.

Next, as shown in FIG.
The rotary shaft 17 is connected to the amplitude grating 4Z for detecting the origin position and the center of the disk 3 by screws 18 in the same direction as the linear direction (Y direction).

At this time, since the connection between the disk hub 8 and the rotating shaft 17 is made in the linear direction (Y direction) connecting the amplitude grating 4Z for detecting the origin position and the center of the disk 3, the disk hub 8 and the rotary shaft 17 are similarly connected when the disk unit is mounted. The eccentricity affects only the Y direction, and does not affect the synchronization between the A-phase signal and the Z-phase signal.

Therefore, in the encoder according to the present embodiment, when the Z-phase signal is detected based on the rotation phase of the disk unit 101, the A-phase signal and the Z-phase signal are stably output without any positional deviation in the X direction. Can be synchronized.

Further, regarding the deviation of the Y direction, the phase A and the phase B
Since the phase and Z phase signals need not be confused,
If the track width of the amplitude grating 4 is 200 μm, 10
A deviation up to 0 μm is acceptable. However, when the rotational phase of the disk 3 is at the detection position of the Z-phase signal, it is advantageous that the deviation in the Y direction is suppressed in terms of synchronization between the A-phase signal and the Z-phase signal.

In the encoder according to the present embodiment, the connection between the disk hub 8 and the rotating shaft 17 is performed in the linear direction (Y direction) connecting the center of the disk 3 with the amplitude grating 4Z for detecting the origin position. Screwing from the direction facing the base 10A.

For this reason, the displacement of the abutment against the block member 10 due to the change in the shaft diameter and the displacement due to the eccentricity caused when the disc hub 8 and the connection shaft 17 are connected are detected by the rotational phase of the connection shaft 17 being the origin. When the position is reached, the direction is affected in the opposite direction, so that the allowable amount of change in the shaft diameter can be further reduced.

Specifically, as shown in FIG. 8, assuming that the V-shaped angle of the block member 10 is θ, the displacement of the disk 3 and the plane substrate 5 in the Y direction at the origin detection position is h = ( D1−D0) × (1 / sin θ−1). Here, assuming that the allowable deviation of the Y direction of the disk unit 101 is 100 μm, the change in the shaft diameter is 0.1 μm.
5 mm or more is allowed, which is generally impossible.
Therefore, the signal quality of the encoder is affected only by the mounting accuracy of the rotary shaft mounted by the user.

Further, regarding the positioning of the disk unit 101 in the Z direction, the holding portion 10 of the block member 10
This is performed by abutting the disk hub 8 on the surface B and pressing the disk hub 8 in the Z direction by the spring member 10C. For this reason, the disk 3
And the positional accuracy of the planar substrate 5 must be suppressed to ± 30 μm.

Therefore, if the error generated during the assembling of the encoder is suppressed to ± 15 μm, the positional accuracy of the disk 3 and the flat substrate 5 is ± 15 μm due to the abutment of the disk hub 8 against the holding portion 10 B of the block member 10. This is a sufficiently guaranteed value.

In the encoder according to the present embodiment, the spring member 10 is attached to the holding portion 10B of the block member 10.
By forming C integrally, the number of component parts is reduced.

[0072]

As described above, according to the present invention, a block member for holding a disk unit on a plane orthogonal to the rotation axis direction is provided on the main unit so as to be movable in the rotation axis direction of the disk unit. The position of the disk unit is defined on a straight line connecting the center of the rotation axis and the light source means by the position defining means of the block member, and the disk unit is temporarily defined by the temporary fixing means of the block member. Since it is fixed, even if it is a built-in type rotational displacement information detecting device including a main body unit having a flat substrate and a light receiving means and a rotatable disk unit having a disk and the like, even if the amplitude grating of the disk is The positioning of the amplitude grating on the flat substrate can be performed easily and with high accuracy.
Since the block member can be fixed to the main body unit in a state where the amplitude grating of the disk and the amplitude grating of the flat substrate are positioned, the position of the disk unit on the plane orthogonal to the direction of the rotation axis of the disk unit is adjusted with the rotation axis center and the light source means. It can be defined on the connecting straight line, and therefore, it is possible to detect the rotational displacement information with high accuracy with little synchronization deviation between the A-phase signal and the Z-phase signal.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part of a rotational displacement information detecting device according to the present invention.

FIG. 2 is a plan view of the rotational displacement information detecting device when the sensor substrate is removed in FIG.

FIG. 3 is an explanatory view of a state in which a concave portion serving as a position defining means of a block member receives a disk unit.

FIG. 4 is a plan view of a block member.

FIG. 5 is a front view of a block member.

FIG. 6 is an explanatory view of a state where the position of the disk unit is defined by a concave portion serving as a position defining means of the block member.

FIG. 7 is an explanatory diagram of a state where a disk unit is screwed to a block member.

FIG. 8 is an explanatory diagram for explaining a positional shift in the Y direction at the origin detection position between the disk and the flat substrate due to a change in the shaft diameter.

FIG. 9 is a schematic diagram of a main part of a conventional rotary encoder.

FIG. 10 is an explanatory diagram showing a fitting relationship between a hub and a shaft in a conventional rotary encoder.

FIG. 11 is an explanatory view showing a positional deviation between a disk eccentricity and a plane substrate in a conventional rotary encoder.

[Explanation of symbols]

Reference Signs List 1 LED (light emitting element) (light source means) 2 Collimating lens (light source means) 3 Disk (main scale) 4, 4Z radiation grating 5 Planar substrate (index scale) 5A, 5B, 5Z Radiation grating 6, 6A, 6B, 6Z sensor (Light receiving means) 10 Block member 10A Base 10B Holding part 10C Springy member (temporary fixing means) 10D Recess (position defining means) 10E V-shaped wall

Claims (7)

[Claims] A light beam guided from a light source means to a radiation grating on a relatively rotating disk and a radiation grating on a flat substrate opposed to the disk, and modulated by the two radiation gratings. In a rotational displacement information detecting device for detecting relative rotational displacement information between the disk and the flat substrate using a signal from the light receiving device, the light source device, the flat substrate, the light receiving device, etc. A block having a main body unit provided therein and a rotatable disk unit having the disk and the like, wherein the main body unit holds the disk unit on a plane perpendicular to the rotation axis direction and is fixed to the main body unit A member is provided so as to be movable in the direction of the rotation axis of the disk unit. A position defining means for defining the position of the disc units above, rotational displacement information detection apparatus which is characterized by providing a temporary fixing means for temporarily fixing the disk unit whose position defined by the position regulating means. 2. The rotational displacement information detecting device according to claim 1, wherein the main body unit is provided with guide means for guiding the block member along a rotation axis direction of the disk unit. apparatus. 3. The block member comprises: a holding portion for holding the disk unit on a plane perpendicular to the rotation axis direction; and a base fixed to the main body unit so as to be movable in the rotation axis direction of the disk unit. The rotational displacement information detecting device according to claim 1, wherein the rotational displacement information detecting device is integrally provided. 4. The position defining means has a V-shaped wall which forms a V-shape around a straight line connecting the center of the rotation axis of the disk unit and the light source means, and utilizes the V-shaped wall to position the disk unit. 2. The method according to claim 1, wherein
2. A rotational displacement information detecting device according to claim 1. 5. The position defining means is formed in a concave portion having a V-shaped wall which forms a V-shape around a straight line connecting the rotation axis center of the disk unit and the light source means, and the V-shaped wall of the concave portion forms the disk unit. The rotational displacement information detecting device according to claim 1, wherein the position is defined. 6. The temporary fixing means is formed of a spring member having elasticity in the rotation axis direction of the disk unit, and temporarily fixes the disk unit using the elasticity of the spring member. The rotation displacement information detecting device according to claim 1. 7. The rotational displacement according to claim 1, wherein the temporary fixing means is formed on a springy member having elasticity in a rotation axis direction of the disk unit and is provided integrally with the block member. Information detection device.