JP2001012968A - Rotary encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the vibration of an encoder even by an axial deflection and to reduce a load to an encoder shaft or a motor shaft by coupling shaft-like members split at least to two or more in a longitudinal direction of the encoder shaft by a springy coupling member. SOLUTION: A shaft is split, that is, split into a shaft 8A and a shaft 8B. The shaft 8A fixes a disc with a disc fixing surface on it upper surface and is accurately rotated by fixing the shaft 8A by a bearing. Accordingly, relative positions of the disc 4 except a rotary component of an index scale are always held constant. Corresponding female threads are cut on a mounting portion of the encoder, and the encoder is fixed by clamping through the treads. Meanwhile, the shaft 8B is engaged with a motor shaft 15, and the shaft 15 is fixed to the shaft 8B by clamping a screw 9. In this state, the shaft 8A is coupled to the shaft 8B by a springy coupling member 11. Since an encoder body is tightly fixed to a motor 14 assembled by screw clamping, the body is not moved to the motor 14 so that no vibration occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary encoder, and more particularly to a built-in rotary encoder which has a bearing inside and can be directly attached to a motor or the like without a coupling or the like.

[0002]

2. Description of the Related Art Conventionally, a rotary encoder has been widely used as an apparatus for measuring relative rotational displacement information of an object with high accuracy. FIG. 4 shows the configuration of a conventional rotary encoder. The incremental signals (A phase, B phase) of the rotary encoder are detected by detecting the position of the main pattern 4A, which is a radial amplitude grating (transmitting or non-transmitting grating) or a light shielding pattern formed on the disk 4 which rotates relatively. Is output.

The light beam generated from the light source unit 1 is collected by a collimator lens 2. After the condensed light passes through the flat substrate 3 provided with the index patterns 3A and 3B, the main pattern 4A is irradiated with a light beam. The index patterns 3A and 3B are formed of radial amplitude gratings (transmitting and non-transmitting gratings) having the same pitch as the main pattern 4A and being spatially shifted from each other by 90 degrees, or slit-shaped light shielding patterns.

After passing through the main pattern 4A, the light beam transmitted through the index pattern 3A is received by the light receiving means 5A, and the light beam transmitted through the index pattern 3B is received by the light receiving means 5B. The amount of transmitted light is modulated so that it becomes the maximum when the patterns of 4A and 3A or 3B overlap, and becomes the minimum when the patterns overlap with a shift of 1/2 pitch. Each light receiving means detects a change in the amount of light in one cycle when the first scales 3A and 3B and the second scale 4A move relative to each other by one pitch, and outputs incremental signals whose phases are shifted from each other by 90 degrees. Light receiving means 5A,
The analog signal from 5B is binarized into an A-phase signal and a B-phase signal, and by counting these two signals, rotational position information can be obtained. The counting is performed, for example, by subtracting 1 from the count value when the state of the signal changes from H to L.

In detecting the origin of the rotary encoder, a plurality of amplitude grating slits are provided at a specific location at a random pitch on a circumference different from the main pattern 4A on the relatively rotating disk 4, or a light-shielding slit is provided at a specific point. This is done by recording the origin pattern 4Z. The transmitted light illuminating the position 4Z passes through the flat substrate 3 provided with the same index origin pattern 3Z as the origin pattern 4Z on the disk 4. The transmitted light is received by the light receiving means 5Z, 4Z,
The light modulation is performed so that the transmitted light amount becomes maximum when the origin pattern of 3Z completely matches, and becomes small when it is shifted beyond the pattern width of the amplitude gratings 4Z and 3Z.

[0006] With the relative rotational movement of the disk 4, the light receiving means 5
From Z, one large mountain-shaped waveform is output. The half-width of the large chevron-shaped waveform coincides with the rotation amount corresponding to the width of the slits of the 4Z and 3Z amplitude gratings. Therefore, if the signal from 5Z is binarized at 1/2 level, a Z-phase signal is obtained, and the width of the Z-phase rectangular wave signal matches the rotation amount corresponding to the slit width of the 3Z amplitude grating.

FIGS. 5 and 6 are provided with detection means as described above,
FIG. 2 is an external view and an internal explanatory view of a conventional built-in encoder that can be assembled by a user himself to a motor or the like without using a coupling or the like.

The light beam emitted from the light source unit 1 passes through the index scale 3 and the rotating optical disk 4 and
The light is received by a light receiving sensor 5 fixed on 6. The principle of signal output is the same as that of the conventional encoder of FIG. In this encoder, a shaft 8 fixed by bearings 7A and 7B is hollow, and can be directly fixed to a motor shaft or the like by a screw 9. Even if the rotation accuracy of the motor shaft is poor,
Since the spring member 11 absorbs the vibration, the encoder follows the rotation of the motor shaft together with the main body, and the signal quality is not affected by the rotation accuracy of the motor.

[0009]

However, in the conventional rotary encoder described above, the signal quality is not affected by the motor rotation accuracy, and the assembling work is easy.
Since the encoder follows the rotation of the motor together with the main body, there is a problem that the encoder main body also vibrates similarly to the shaft shake. Since the encoder body vibrates in various directions due to the shaft deviation of the motor, the load applied to the motor shaft is large, and it is not preferable that the highly-adjusted encoder vibrates according to the rotation of the motor. In an extreme case, a problem such as a detachment of an adhesive part of an optical component or the like may be considered.

[0010] Further, when the spring property of the spring member 11 is set to be strong, the problem of the shaft deflection of the motor shaft being transmitted to the encoder shaft 8. Conversely, when the spring property of the spring member 11 is set to be weak, the encoder main body is not provided. Encoder shaft 8 with 12 inertial forces
Or a vibration inherent in the encoder main body 12 and the motor shaft occurs, and a difference in the vibration causes a problem that a force corresponding to the mass of the encoder main body is applied to the encoder shaft 8. Therefore, in both cases, a load is applied to the encoder shaft 8, which causes the shaft 8 to shake.

The above problem causes a certain degree of eccentricity of the disk 4, which makes it difficult to construct a highly accurate encoder. Also, since a load is applied to the encoder shaft 8, a relatively same amount of load is applied to the motor shaft, which is not preferable.

[0012]

According to a first aspect of the present invention, there is provided a rotary encoder which includes a bearing and which can be attached to a motor or the like without using a coupling. Divided into at least one shaft-shaped member,
It is characterized in that two or more divided shaft members are connected by a spring connection member.

According to a second aspect of the present invention, in the first aspect of the present invention, the shaft member divided into two or more is a cylindrical component for fixing a rotating disk provided with a signal pattern, and a shaft diameter of a motor or the like to be incorporated. It is characterized by including a cylindrical part to be fitted.

According to a third aspect of the present invention, in the second aspect of the present invention, the spring connecting member has a degree of freedom in a direction perpendicular to the axis, an axial direction, and a direction in which the axis falls.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the spring connecting member maintains the rotational phase of the disk of the rotary encoder and the motor shaft.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the shaft diameter and the amount of shaft deviation of the motor and the like are provided on the spring connecting member and the cylindrical part constituting the encoder shaft divided into two or more parts. A hole having a diameter larger than the sum of the above is provided, and a shaft of the motor or the like is penetrated.

[0017]

1 and 2 show a first embodiment of a built-in encoder according to the present invention. In the present embodiment, in a built-in rotary encoder incorporating a bearing, the encoder shaft is divided into at least two or more in the longitudinal direction of the shaft, and the shaft on the user shaft side to be built is formed as a hollow shaft.
The axial member divided into two or more parts is the axis direction, the direction perpendicular to the axis,
It is characterized in that it is connected by a connecting member having spring properties in the direction in which the shaft falls. By dividing the encoder shaft into two or more parts, the encoder and the motor to be mounted do not move relative to each other, so even if there is shaft shake, the encoder does not vibrate, and a built-in rotary encoder with a small load on the encoder shaft (bearing) is realized. are doing. The same members as those in the conventional embodiment are denoted by the same reference numerals.

The optical configuration is the same as that of a conventional encoder, and the light beam emitted from the light emitting element 1 passes through the index scale 3. On the index scale 3, an origin pattern 3Z is provided. When the rotating disk 4 rotates, the origin pattern 4Z provided at one point on the disk circumference and the origin pattern 3Z on the index scale 3 come to a position where they overlap with an incremental signal which is a main signal according to the rotation angle of the disk 4. Sometimes an origin signal is generated. The two signals are output as photoelectric signals by a sensor 5 provided on an electric board 6.

In this embodiment, the shaft 8 is divided into two parts, that is, the shaft 8A and the shaft 8B. The shaft 8A has a disk fixing surface on the upper surface, fixes the disk 4, is fixed by bearings 7A and 7B, and rotates with high precision. Therefore, the relative positions of the disk 4 and the index scale 3 other than the rotation components are always kept constant. The motor 14 has a female thread corresponding to the mounting portion 13 of the encoder, and the encoder is screwed and fixed. On the other hand, axis 8B
Is engaged with the motor shaft 15, and screw the motor shaft 15
It is screwed and fixed by 9. In this state, a feature of the present invention is that the shafts 8A and 8B are connected by a springy connecting member (springy member) 11.

That is, in this embodiment, in two cylindrical shafts 8A and 8B arranged at the rotation center of the shaft, a rotating disk provided with a signal pattern is fixed to 8A, and a motor to be incorporated is mounted to 8B. A fitting hole is provided that has a fitting relationship with the shaft diameter.
The configuration is such that two cylindrical parts are connected by a spring member 11.

FIG. 3 shows the detailed shape of the spring member 11. The spring member 11 has a direction perpendicular to the axis, an axial direction,
Since there is a degree of freedom in the direction in which the shafts fall, the shafts 8A and 8B are configured to be freely movable while maintaining only their rotational phases. There is no particular limitation on the resiliency of the resilient member 11, and it suffices that only the rotational phase of the disk 4 and the motor shaft 15 be maintained. Therefore, a built-in encoder with a low load on both the encoder shaft 8A and the motor shaft 15 can be configured.

In the case of the above configuration, since the encoder body is firmly fixed to the built-in motor by screwing, it does not move with respect to the motor and does not generate vibration. Vibration caused by motor shaft deflection does not occur for electric components including the light source, index scale, rotating disk, and various optical components including the sensor. Therefore, reliability in bonding components and mounting electric components is extremely high.

Also, the encoder shaft is hollow and divided into 8A and 8B, and both are connected by a spring member 11 having spring properties other than the rotation direction of the shaft. Therefore, the index scale and the rotating disk always maintain their relative positions in the plane direction and the axial direction perpendicular to the axis.

If the shaft diameter of the shaft 8A is a cylindrical hollow shaft having an inner diameter equal to or greater than the diameter of the motor shaft plus the amount of shaft deviation as a fitting relationship, a hollow encoder can be easily configured. Further, if a hole having a diameter larger than the shaft diameter of the motor or the like is provided in the cylindrical component or the spring member, the motor shaft can be penetrated.

A plurality of shaft-like members corresponding to the shaft 8B are provided,
If each member is connected by a spring-like member equivalent to the spring-like member 11, the load on the shaft 8A is smaller, that is, the relative position shift other than the rotation phase of the rotating disk 4 and the index scale does not occur, and the encoder shaft 8A, An encoder with a small load on the motor shaft 15 can be configured.

[0026]

As described above, in the built-in type rotary encoder incorporating the bearing of the present invention, the encoder shaft is at least two times in the longitudinal direction of the shaft.
The shaft on the user shaft side to be incorporated is divided into two or more, and the shaft on the user shaft side to be incorporated is made a hollow shaft, and each of the divided shaft members is connected by a connecting member having a spring property in the axial direction, the direction perpendicular to the shaft, and the falling direction of the shaft. It is characterized by. By dividing the encoder shaft and connecting it with a springy member, the encoder and the motor to be mounted do not move relative to each other, that is, the encoder does not vibrate even if there is shaft deviation, so high accuracy and reliability are high, and the encoder shaft, A built-in rotary encoder with a small load on the motor shaft can be realized.

Further, by forming the divided shaft-like members by cylindrical parts and by appropriately selecting the fitting relationship with the motor shaft to be connected, a stable built-in rotary encoder with a small load on the motor shaft can be obtained. Can be realized.

[Brief description of the drawings]

FIG. 1 is an external view (partially transparent view) of a main part of a first embodiment of the present invention;

FIG. 2 is an internal explanatory view of Embodiment 1 of the present invention,

FIG. 3 is a detailed view of a spring member according to the first embodiment of the present invention,

FIG. 4 is an explanatory view of a conventional encoder,

FIG. 5 is an external view of a conventional built-in encoder,

FIG. 6 is an internal explanatory view of a conventional built-in encoder.

[Explanation of symbols]

 1 Light emitting element or light source unit, 2 Collimator lens, 3 Index scale, 4A Main signal pattern, 4Z Origin signal pattern, 5, 5A, 5B, 5Z light receiving sensor, 6 Electrical board, 7A, 7B bearing, 8, 8A, 8B axes, 9 setscrew, 10 encoder optical base, 11 spring member, 12 encoder cover, 13 encoder, stop member for connecting motor, etc., 14 motor, 15 motor shaft

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shujiro Kadowaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yasushi Yasuda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Takayuki Kadoshima 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Sakae Horitaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F term (reference) 2F077 AA42 NN02 NN30 PP19 QQ11 VV07 VV23 VV31 VV35

Claims (5)

[Claims] 1. A rotary encoder having a built-in bearing and attachable to a motor or the like without using a coupling, wherein the encoder shaft is divided into at least two or more shaft members in a longitudinal direction of the shaft, and the at least two shaft members are divided into at least two shaft members. A rotary encoder characterized in that the shaft members divided as described above are connected by a spring connection member. 2. The method according to claim 1, wherein the shaft member divided into two or more parts includes a cylindrical part for fixing a rotating disk provided with a signal pattern, and a cylindrical part for fitting with a shaft diameter of a motor or the like to be incorporated. The rotary encoder according to claim 1, wherein 3. The rotary encoder according to claim 2, wherein said springy connecting member has a degree of freedom in a direction perpendicular to said axis, in an axial direction, and in a direction in which said axis falls. 4. The rotary encoder according to claim 3, wherein said springy connecting member keeps the rotation phase of said rotary encoder disk and said motor shaft. 5. A motor according to claim 1, wherein said spring connection member and said cylindrical part constituting said encoder shaft divided into two or more are provided with a hole having a diameter larger than the sum of the shaft diameter of said motor or the like and the amount of shaft deviation. 5. The rotary encoder according to claim 4, wherein a shaft such as is penetrated.