JP2003014497A - Encoder, and mounting method of encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized and low-price encoder capable of being positioned and assembled easily with excellent repeatability with a comparatively simple structure, and its mounting method. SOLUTION: Concerning this encoder, the encoder body is mounted on a measuring object 2. The encoder is constituted so that the encoder body has a code plate unit 3 and an encoder unit 101 for reading the code of the code plate unit 3, and that the encoder unit 101 has a positioning means for performing positioning in contact with a cylindrical projection part formed around a rotary shaft 11 of the measuring object 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoder for detecting a displacement amount, a rotation amount, and a rotation speed of an object to be measured, which is a rotating body such as a motor, and more particularly to providing a slit plate unit and an encoder unit to a user. Relates to a kit type encoder in which this is assembled to an object to be measured to form an encoder, and a mounting method thereof.

[0002]

2. Description of the Related Art A rotary encoder converts a mechanical rotational displacement amount into an electric signal, amplifies it, and outputs it. Above all,
An optical rotary encoder (hereinafter, simply referred to as an encoder) is a slit plate unit that extracts a mechanical rotational displacement amount, and converts the displacement into an electrical signal and outputs the electrical signal.

A configuration example of such an encoder is shown in FIG. In the figure, an encoder shaft 311 is rotatably held in the encoder body 312 via two bearings 313a and 313b. A code plate 324 is attached to the encoder shaft 311 via a boss 325, and the code plate 324 is rotated by the rotation of the encoder shaft 311.

A wiring board 317 having an electric circuit component 318 and a light emitting element 321 mounted on the encoder body 312.
Is attached. An input / output cable 316 is connected to the circuit board 317 so that signals and the like can be exchanged with an external circuit. A light receiving element 322 is arranged at a position facing the light emitting element 321 with a code plate 324 in between, and a light receiving element 322 is disposed via a fixed slit 323. Thereby, the light emitted from the light emitting element 321 is transmitted to the code plate 324.
Is input to the light receiving element 322 via the slit of the slit and the slit of the fixed slit plate 323. Therefore, the encoder shaft 31
By the rotation of 1, the light is input to the light receiving element in accordance with the slit of the predetermined pattern provided on the code plate 324, and an electric signal (code pulse) corresponding to the rotation is generated. These encoder unit, code plate and the like are housed in a case 315 and integrated with the main body. The encoder shaft 31
A rotary shaft of an object to be measured such as a motor is usually connected to the side opposite to the code plate 1.

Although there are various types of encoder structures, there is a kit type encoder in which the slit plate unit and the encoder unit are separately provided to the user, and the user assembles them to form an encoder. This kit type encoder is designed for cost reduction and space saving.
It has only the minimum functional part of the encoder.

FIG. 8 shows an example of the structure of a kit type encoder. In FIG. 8, a circuit board 17 is attached to an object to be measured 2 such as a motor via a fixing base 1 fixed by fixing screws 15.
Is fixed. This circuit board 17 has electrical parts 1
8 and the light receiving element 22 are mounted. Further, at a position facing the light receiving element 22 attached to the fixed base 1 on the DUT 2, the fixed slit 2 is provided via the code plate 24.
3 and the light emitting element 21 are arranged. Therefore, the light emitted from the light emitting element 321 passes through the slit of the fixed slit plate 23 and the slit of the code plate 24, and the light receiving element 22.
To enter. Therefore, when the shaft 11 rotates, the code plate 24
Light is input to the light receiving element according to the slit of the predetermined pattern provided on the, and the electric signal (code pulse) according to the rotation
Occurs.

Such a kit-type encoder is provided with a rotating body and a bearing (and a cover) by being attached to a rotating body which is the object to be measured 2, for example, a shaft end of the motor opposite to the output shaft of the motor. Even if it does not exist, in other words, the function of the other party is utilized to exert the function as the encoder.

In the meantime, the manufacturer of the kit-type encoder assembles the slit plate unit and the encoder unit on a dedicated jig once in the manufacturing process, confirms the function, and then disassembles the unit to disassemble the unit. Provided in the state of. A user who purchases the kit-type encoder can function as an encoder by assembling the kit-type encoder on the rotating shaft of the object to be measured (for example, a motor).

Among the performances of the encoder, the precision of the output signal waveform is the most important performance. The accuracy is (1) the rotation accuracy of the rotating body (for example, the motor shaft). (2) Accuracy of rotation and fixed slit plate's own slit to detect it. (3) Assembling accuracy of the slit plate unit and the encoder unit to the rotating body. (4) Detection accuracy of the slit plate unit. (5) Accuracy of conversion into electric signals. Etc. are combined and appear.

Therefore, in order to obtain a desired accuracy, for each of the above items, (1) is the accuracy managed by the user and is within the required range (hereinafter referred to as the standard). Importantly, it is easy to solve from the current general processing technology. In (2), although it is required that the accuracy of the slit and the accuracy of the peripheral parts are within the standard range, it can be solved by a general existing technology. (4) and (5) can be solved by the common existing technology as in (2). In the case of the kit type encoder, the problem (3) is the most problematic.

This is a problem that can be solved by the manufacturer, but for general users who are not familiar with the structure and characteristics of the encoder, the technique relating to the assembly of the encoder can be applied to the object to be measured such as a motor. This is because it is required at the time of assembling, and the assembling accuracy greatly depends on the signal waveform accuracy.

The manufacturer of the encoder once assembles it and confirms its function as an encoder. If it can be disassembled and reproduced as it is, there is no problem, but a considerable accuracy is required. There are many difficult points.

Therefore, in order to solve this problem, the following method has been generally adopted.

In order to position the encoder unit,
On the encoder mounting surface of the motor, generally provided with convex convex parts and concave concave eye parts (usually referred to as "inlay") on the opposite encoder side, and by aligning these parts, centering is performed. Came. However, in recent years, the demand for accuracy has increased, and it is difficult to reproduce the accuracy of the encoder with commonly used fitting accuracy (for example, hole H7, shaft h7, etc.), and higher accuracy is required. Satisfaction has many problems in terms of cost and the like.

As a countermeasure, there is a method in which the position of the encoder unit is adjusted while observing the output signal by assembling on a flat surface without using a spigot. However, this is not practical because the manpower and skill required for adjustment are required from the user side.

Further, various methods for solving this have been proposed. For example, utility model registration No. 161443
No. 0, as described in JP-A-6-3163,
A method using a taper and a boss provided on the encoder body is known.

However, these are very effective for small kit type encoders, but for large size kit type encoders, the shape of the encoder unit is a ring (ring shape) or a part of the ring. It must be cut out, and as a whole, the components that make up the encoder unit must be made large. However, current electronic technology allows the size of major circuit components to be small, so that it is possible to make it small enough to use a part of the ring without using a ring-shaped printed circuit board. For this reason, if formed in a ring shape, the area is large and the yield is poor, so that the cost effect does not appear.

[0018]

SUMMARY OF THE INVENTION An object of the present invention is to provide an encoder which has a relatively simple structure, can be easily and reproducibly positioned and assembled, and is small in size and low in cost, and a method for mounting the encoder. .

[0019]

That is, the above object can be achieved by the following constitution. (1) An encoder in which an encoder body is attached to a DUT (2), the encoder body including a code plate unit (3) and an encoder unit (101) for reading the code of the code plate unit (3). The encoder unit (101) is an encoder having a positioning means for performing positioning by contacting a cylindrical convex portion formed around the rotary shaft (11) of the DUT (2). (2) The positioning means has an arcuate contact portion having a radius equal to or less than the circular radius of the cylindrical projection, and the arcuate contact portion is brought into contact with the side surface of the cylindrical projection. The encoder of (1) above for positioning. (3) The encoder according to (1) or (2) above, wherein the positioning means further includes an abutting protrusion for contacting the cylindrical protrusion. (4) A method for mounting an encoder, wherein an encoder body (101) is mounted on a DUT (2), wherein the encoder is a cylindrical projection formed around a rotary shaft (11) of the DUT (2). A method of mounting an encoder, comprising: positioning means for contacting a portion for positioning, and positioning the encoder body with respect to the object to be measured (2) by this positioning means, and then fixing the encoder body to the object to be measured.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An encoder according to the present invention is an encoder in which an encoder body is attached to an object to be measured 2. The encoder body is a code plate unit 3 and an encoder unit for reading the code of the code plate unit 3. 101, and the encoder unit 101 has a positioning unit that contacts a cylindrical convex portion formed around the rotary shaft 11 of the DUT 2 to perform positioning.

As described above, by having the positioning means for contacting with the cylindrical convex portion formed around the rotation axis of the object to be measured, the code plate unit is properly positioned at the time of adjustment once assembled. The positional relationship between the encoder unit and the encoder unit can be easily and accurately reproduced even when reassembled.

That is, since the code plate unit is attached to the rotary shaft of the object to be measured, the relative position with respect to the rotary shaft is automatically determined by positioning the cylindrical convex portion formed around the rotary shaft and the positioning means. The positional relationship in the axial direction with the code plate unit will be determined. Since the positioning means mechanically determines the positional relationship by contacting the cylindrical convex portion, once adjusted, once adjusted, fine adjustment is not required when reassembling. Therefore,
By setting the position to a mechanically determined position by this positioning means, the positional relationship at the time of adjustment can be reproduced with extremely high accuracy.

The positioning means is capable of providing a mechanical positional relationship by contacting a cylindrical convex portion formed around the rotation axis of the object to be measured, and preferably at two or more contact points. Positioned. As such a positioning mechanism, various structures are conceivable, but in the present invention, in particular, the cylindrical convex portion, that is, an arcuate contact portion having a radius equal to or smaller than the circular radius of the spigot portion, A method is used in which the arcuate abutting portion is brought into contact with the side surface of the cylindrical convex portion to perform positioning.

More specifically, an object to be measured, for example, a cylindrical convex portion, that is, a spigot, is formed around the rotation axis of the motor, and the contact portion has a radius equal to or smaller than the circular radius of the spigot. Are formed in the encoder unit. Then, the contact portion is pressed against the side surface of the spigot for positioning. Therefore, the positioning operation is performed only by the contact operation between the contact portion and the side surface of the spigot, and the positioning can be performed very easily.

Here, the size of the contact portion required for positioning, that is, the size of the portion pressed against the spigot side surface is less than 180 °, preferably 160 ° to 15 °, when viewed from the center of the rotating shaft. , And even 120 ° ~
It suffices that the angle is within 30 °, particularly 90 ° ± 20 °. The amount of protrusion of the spigot part varies depending on the size of the object to be measured, but is usually 1 to 5 mm, especially 2 to
3mm is enough.

The circular radius of the arcuate contact portion of the positioning mechanism may be equal to that of the spigot, but is preferably slightly smaller than this. By making the arc radius of the contact part smaller than the radius of the spigot,
The two corner portions of the contact portion come into contact with the spigot side surface, which improves the positioning accuracy and reduces the influence of dust and the like.

In this case, the radius of the arcuate abutting portion is preferably 70 to 98%, particularly 85 to 95% of the radius of the spigot. If the radius of the abutting portion is smaller than this, the positioning accuracy is lowered and the positioning work becomes difficult.

The encoder unit of the present invention is fixed by tightening the fixing screw after positioning by the positioning mechanism. At this time, it is advisable to temporarily fix the fixing screw at the time of positioning.

Next, a more specific structure of the present invention will be described. FIG. 1 is an assembly diagram showing a configuration example of a kit type encoder of the present invention.

In the figure, an encoder unit 101
Is a wiring board 1 on which the light emitting element 21 and electric circuit parts are mounted.
02, the fixed slit plate 22, the light receiving element 23 and the wiring board 104 on which the electric circuit parts are mounted, and the main body 103
It has a screw 106 and a spacer 105 for fixing to. Further, the main body 103 is provided with mounting holes 121a and 121b for fixing to the object to be measured, and the mounting screws 5a and 5b and the fixing screw hole 211 are provided.
It can be fixed to the DUT 2 by a and 211b. The wiring board 102 and the wiring board 104 are electrically connected by a connecting means (not shown).

The main body 103 has a spigot of the object to be measured 2, that is, an arcuate contact portion 113 for contacting the cylindrical convex portion 12, as positioning means.

A cylindrical convex portion 12 for positioning is formed around the rotary shaft 11 of the DUT 2. Further, a code plate 24 fixed to a boss 25 is attached to the rotary shaft 11. This boss 25 has a screw hole 25a for fixing it to the rotating shaft 11, and a boss 25 is provided so that the code plate 24 can be arranged at an optimum position between the light emitting element and the light receiving element by a fixing screw (not shown). The fixed position of can be adjusted.

When the user assembles the object to be measured, for example, the non-driving shaft side of the motor, the circular arc-shaped contact portion 113 is pressed against the side surface of the cylindrical convex portion 12 formed around the rotary shaft 11. It is abutted, positioned, and fastened and fixed by two mounting screws (5a, 5b) for fixing the encoder unit 103. At this time, the mounting screws (5a, 5
It is also possible to perform temporary fastening with b) and to perform final tightening after positioning.

With this, the positional relationship in the radial direction is reproduced. Next, adjustment is made in the axial center (axial) direction. This means that the "gap" between the rotary slit plate and the fixed slit plate (hereinafter referred to as "gap") must be kept at a specified value. Various proposals have been made for this method as well, but the most known method is to use a spacer for gap adjustment, that is, a "clearance gauge" (shim).

The kit type encoder does not have a rotating structure by itself. Therefore, the manufacturer assembles the encoder unit and the slit plate unit on a jig called a "rotating jig" such as a motor in order to assemble and confirm the performance, and confirms the performance.

Then, it is disassembled into each unit to be supplied to the user. Before this disassembly work, the positional relationship with the motor shaft is determined by the positioning by the arcuate contact portion. At this time, it is preferable to perform a fixing operation such as applying a locking agent or an adhesive to each fixing portion of the main body so as not to loosen during movement such as during transportation. After that, it is removed from the rotating jig and disassembled.

In the case of the optical type, the encoder unit used in the present invention is usually a pair of a light emitting element and a light receiving element, and drives these elements, amplifies and shapes the obtained signal, and adjusts the timing. It is composed of electronic circuit parts for trimming. A semiconductor light emitting element such as a light emitting diode (LED) or a laser diode (LD) is usually used as the light emitting element, and a semiconductor light receiving element such as a phototransistor or a photodiode is usually used as the light receiving element. When a magnetic detection method is used, it is composed of a magnetic detection element and electronic circuit parts.

The code plate in the present invention is an optical type,
Usually, a disk-shaped slit plate having a light transmitting portion (so-called slit) and a light shielding portion is used. A known incremental signal or absolute signal can be obtained by combining the light transmitting material and the light shielding portion. When the magnetic method is used, the same effect as the slit plate can be obtained by combining the magnetic transmission part and the magnetic shielding part, or the magnetic material and the non-magnetic material, and the magnetic generation part and the non-magnetic generation part. You can

<Embodiment 1> Next, a more specific embodiment of the present invention will be described. 2 is a partial plan view showing a kit type encoder according to a first embodiment of the present invention, FIG. 3 is a front view of FIG. 2, and FIG. 3 is a side view of FIG. In this example,
The case where the circular radius of the arcuate contact portion 113 and the radius of the spigot, that is, the cylindrical convex portion 102 are the same is shown.
The other configurations are the same as those in FIG. 1, and the same components are designated by the same reference numerals and the description thereof will be omitted.

As described above, when the circular radius of the arcuate contact portion 113 and the radius of the cylindrical convex portion 102 are the same, precise positioning by surface contact is possible, but it is also affected by dust and the like. It will be easier.

<Second Embodiment> FIG. 5 is a partial plan view showing a kit type encoder according to a second embodiment of the present invention.
In this example, the circular radius of the arcuate contact portion 113 is smaller than the radius of the cylindrical convex portion 102. The other configurations are the same as those in FIG. 1, and the same components are designated by the same reference numerals and the description thereof will be omitted.

In this way, by making the circular radius of the arcuate contact portion 113 smaller than the radius of the cylindrical convex portion 102, both ends of the circular arc come into contact with the side surface of the cylindrical convex portion 102. Positioning can be performed in a state close to contact, and in this case also, positioning can be performed with high accuracy, and the effects of dust and the like can be eliminated. Further, the machining accuracy of the arc itself of the arc-shaped contact portion 113 is not so required, and there is a cost reduction effect.

<Third Embodiment> FIG. 6 is a partial plan view showing a kit type encoder according to a third embodiment of the present invention.
In this example, the circular radius of the arcuate contact portion 113 and the radius of the cylindrical convex portion 102 are substantially the same, but the arcuate contact portion 113 is the same.
Further, a convex portion 113a is further provided on the above, and the convex portion 113a is brought into contact with the side surface of the cylindrical convex portion 102 for positioning. The other configurations are the same as those in FIG. 1, and the same components are designated by the same reference numerals and the description thereof will be omitted.

Thus, the convex portion 1 is formed on the arcuate contact portion 113.
By providing 13a and bringing the convex portion 113a into contact with the side surface of the cylindrical convex portion 102, the side surface of the cylindrical convex portion 102 is brought into contact with the side surface of the cylindrical convex portion 102 in a state close to point contact. Also, the effects of dust can be eliminated. Further, the machining accuracy of the arc itself of the arc-shaped contact portion 113 is not so required, and there is a cost reduction effect.

The tip portion of the convex portion 113 may be processed into a shape conforming to the side surface of the cylindrical convex portion 102,
It may have a planar shape, or may have a shape protruding so as to draw an arc. Furthermore, without forming a clear projecting shape,
The convex portion may be formed by a curved surface that projects in the direction opposite to the arc. In any case, there are two or more convex portions, and the distance between the outermost convex portions must satisfy the size of the arcuate contact portion 113.

In the above example, an example in which the present invention is applied to an optical encoder has been described, but the present invention is not limited to such an optical encoder, and for example, a magnetic signal is recorded on the circumference. The same method as described above can be used in a magnetic encoder having a foundation drum and a magnetic head for detecting the drum.

[0047]

As described above, according to the present invention, it is possible to provide an encoder which has a relatively simple structure, can be easily and reproducibly positioned and assembled, and is small in size and low in cost, and a method for mounting the encoder. .

[Brief description of drawings]

FIG. 1 is an assembled perspective view showing a configuration example of a kit type encoder of the present invention.

FIG. 2 is a plan view showing a first configuration example of the encoder unit of the present invention.

FIG. 3 is a front view showing a first configuration example of the encoder unit of the present invention.

FIG. 4 is a side view showing a first configuration example of the encoder unit of the present invention.

FIG. 5 is a plan view showing a second configuration example of the encoder unit of the present invention.

FIG. 6 is a plan view showing a third configuration example of the encoder unit of the present invention.

FIG. 7 is a cross-sectional view showing a configuration example of a conventional encoder.

FIG. 8 is a partial cross-sectional view showing a configuration example of a conventional kit type encoder.

[Explanation of symbols] 2 DUT 3 boss 11 rotation axis 16 I / O cable 21 Light emitting element 22 Fixed slit plate 23 Light receiving element 24 code plate 103 main body

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Claims (4)

[Claims] 1. An encoder in which an encoder body is attached to a DUT (2), the encoder body comprising a code plate unit (3) and an encoder unit (101) for reading the code of the code plate unit (3). ) And the encoder unit (101) is a device under test (2).
An encoder having a positioning means for positioning by contacting a cylindrical convex portion formed around the rotation axis (11). 2. The positioning means has an arcuate contact portion having a radius equal to or less than the circular radius of the cylindrical convex portion, and the arcuate contact portion contacts the side surface of the cylindrical convex portion. The encoder according to claim 1, wherein the encoder performs positioning. 3. The encoder according to claim 1, wherein the positioning means further includes an abutting protrusion for contacting the cylindrical convex portion. 4. An encoder body (10) is attached to the object (2) to be measured.
1) is a method of attaching an encoder, wherein the encoder has a positioning means for performing positioning by contacting a cylindrical convex portion formed around a rotation axis (11) of the object to be measured (2), An encoder mounting method for positioning the encoder body with respect to the object to be measured (2) by this positioning means, and then fixing the encoder body to the object to be measured.