JP3639827B2 - Motor system with optical encoder and optical encoder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary optical encoder connected to a rotary shaft of a motor.
[0002]
[Prior art]
The encoder is used as a detector in a servo system, and is used for magnetically and optically detecting the rotational speed of a motor or the like, or the position and speed of an object that performs linear motion. Among these, a rotary optical encoder that detects the rotational speed of a motor or the like includes a disk-shaped code plate, a light projecting unit, and a light receiving unit that are attached to a rotating shaft via an attachment unit. The disc portion of the code plate is provided with a predetermined pattern for modulating the light received from the light projecting portion in response to the rotation, for example, a pattern in which slit-like light transmitting portions and light shielding portions are periodically arranged. It has been. The light receiving unit receives light transmitted through a predetermined pattern on the code plate, and detects the rotational speed of the rotating shaft.
[0003]
In order to increase the resolution of the optical encoder, it is necessary to efficiently transmit and block light on the code plate. However, since the conventional code plate is a glass plate provided with a pattern by Cr vapor deposition, there are problems such as being easily broken, heavy, and high in cost. On the other hand, in the encoder 50 shown in FIG. 7 (see, for example, Patent Document 1), the code plate 56 is formed by integrally forming a disc portion 55 having a pattern and an attachment portion 54 to the rotary shaft 51 with resin. It is lighter. When the code plate 56 of the encoder 50 is manufactured, as shown in FIG. 8A, the gate 63 which is a resin injection port is a lid portion of the code plate 56 so that the resin flow at the time of integral molding is axisymmetric. 59 is located in the center above. Thereafter, the code plate 56 integrally formed by cutting the gate 63 is obtained (FIG. 8B). The lid portion 59 of the code plate 56 is fixed to the end portion of the rotating shaft 51 of the motor with an adhesive 58 (FIG. 7).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-14404
[Problems to be solved by the invention]
When the code plate 56 having a lid is bonded and fixed to the shaft end of the rotating shaft 51 of the motor, if the error in the length of the rotating shaft 51 of the motor is large, the gap adjustment between the disk portion 55 and the light receiving portion is adjusted. Necessary. For this reason, when adjusting the mounting position in the thrust direction, if the contact length in the thrust direction between the rotating shaft 51 of the motor and the mounting portion 54 is shortened, sufficient stability cannot be obtained and the surface deflection of the disk increases. . Further, because of the adjustment in the thrust direction, the distance between the lid 59 and the shaft end of the rotating shaft 51 of the motor is not constant, and the adhesive force is not stable. Furthermore, depending on the resin material, light transmission is not sufficient, and when a UV curable adhesive is used, sufficient adhesive force by the adhesive 58 inside the lid 59 may not be obtained.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optical encoder that facilitates the adjustment of the attachment between the rotating shaft of the motor and the code plate and stabilizes the attachment of the code plate.
[0007]
[Means for Solving the Problems]
The motor system with an optical encoder according to the present invention includes a cylindrical mounting portion having a through hole in the center, and a predetermined pattern that extends radially outward from the mounting portion and transmits light received from the outside. A cord plate provided with a disk part having
A motor having a rotating shaft to be inserted into the through hole, the first shaft portion of one shaft end having a first outer diameter substantially equal to the inner diameter of the through hole, and the first outer diameter; A second shaft portion having a small second outer diameter and adjacent to the first shaft portion, wherein the second shaft portion is fixed to the mounting portion with an adhesive at one opening portion of the through hole. And a motor having a rotating shaft.
[0008]
The motor system with an optical encoder according to the present invention is the motor system with an optical encoder, wherein the first shaft portion of the rotating shaft has an axial length shorter than a length of the through hole. It is characterized by.
[0009]
Furthermore, the motor system with an optical encoder according to the present invention is the motor system with an optical encoder, wherein the axial length of the first shaft portion and the axial length of the second shaft portion of the rotating shaft are as follows. And the total length is longer than the length of the through hole.
[0010]
Furthermore, the motor system with an optical encoder according to the present invention is the motor system with an optical encoder, wherein a transparent resin plate is used as a disc portion of the code plate.
[0011]
Further, the motor system with an optical encoder according to the present invention is the motor system with an optical encoder, wherein the code plate is provided with a reflective layer for reflecting the light received from the light projecting unit. It is characterized by being.
[0012]
Furthermore, the motor system with an optical encoder according to the present invention is the motor system with an optical encoder, and a light projecting unit that projects light onto the pattern of the disk portion of the code plate,
And a light receiving portion that receives light transmitted through the pattern of the disc portion of the code plate.
[0013]
An optical encoder according to the present invention includes a cylindrical mounting portion having a through hole in the center, and a circular pattern having a predetermined pattern on the outer peripheral portion extending radially outward from the mounting portion and transmitting light received from the outside. A cord plate provided with a plate portion;
A rotary shaft to be inserted into the through hole, a first shaft portion of one shaft end having a first outer diameter substantially equal to the inner diameter of the through hole, and a second smaller than the first outer diameter A second shaft portion adjacent to the first shaft portion and a third shaft portion at the other shaft end attached to the rotating shaft of the motor, and in one opening portion of the through hole, The second shaft portion includes the attachment portion and a rotating shaft fixed with an adhesive.
[0014]
The optical encoder according to the present invention is the optical encoder, wherein a transparent resin plate is used as a disc portion of the code plate.
[0015]
The optical encoder according to the present invention is the optical encoder, wherein the disk portion of the code plate is provided with a reflective layer for reflecting the light received from the light projecting portion. .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
A motor system with an optical encoder and an optical encoder according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the drawings, substantially the same members are denoted by the same reference numerals.
[0017]
Embodiment 1 FIG.
A motor system with an optical encoder according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view including the axis center showing the positional relationship between the code plate 6 and the rotating shaft 1 of the motor 20 constituting the motor system 10 with an optical encoder. FIG. 2 is a schematic diagram showing the arrangement of the light projecting unit 11 and the light receiving unit 12 in the motor system 10 with an optical encoder. FIG. 3 is a schematic cross-sectional view of the shaft center showing the positional relationship when the rotary shaft 1 is attached to the rotary shaft 22 of the motor 20 in a motor system with an optical encoder different from FIG. FIG. 4 is a schematic view showing the disc portion 5 and the attachment portion 4 of the code plate 6 integrally formed of resin. The optical encoder 10 includes a code plate 6 having a cylindrical attachment portion 4 having a through hole 7 in the center and a disc portion 5 extending radially outward from the attachment portion, and the through hole 7. And a rotating shaft 1 of the motor 20 to be inserted. The disc portion 5 of the code plate 6 is made of a transparent resin, and the disc portion 5 has a predetermined pattern for modulating the light received from the outside according to the rotation, for example, a slit-like light transmitting portion and a light shielding portion. Have patterns arranged periodically. The rotating shaft 1 of the motor 20 includes a first shaft portion 2a and a third shaft portion 2b at both ends having a first outer diameter substantially equal to the inner diameter of the through hole 7, and a first shaft portion 2a at both ends. And a third shaft portion 2b, and a second shaft portion 3 having a second outer diameter smaller than the first outer diameter. The surface of the second shaft portion 3 is roughened so as to increase the adhesive strength. Furthermore, the length of the first shaft portion 2 a in the axial direction is shorter than the length of the through hole 7, and the sum of the length of the first shaft portion 2 a and the length of the second shaft portion 3 is longer than the length of the through hole 7. The first shaft portion 2 a of the rotating shaft 1 of the motor 20 is inserted into the through hole 7, and the second shaft portion 3 is fixed to the mounting portion 4 with an adhesive at the opening portion of the through hole 7.
[0018]
As shown in FIG. 2, the detection system of the motor system 10 with an optical encoder includes a disc portion 5 of the code plate 6, a light projecting portion 11 provided with the disc portion 5 interposed therebetween, and a light receiving portion. Twelve. As described above, the disc portion 5 of the code plate 6 has a predetermined pattern that transmits the disc portion. In the motor system 10 with an optical encoder, the light from the light projecting unit 11 is modulated by passing through a predetermined pattern of the disc unit 5, and the modulated light is received by the light receiving unit 12.
[0019]
FIG. 3 is a schematic cross-sectional view showing a positional relationship when the rotary shaft 1 of the optical encoder is separated from the motor 20 and attached to the rotary shaft 22 of the motor 20 in another motor system with an optical encoder. It is. In this case, since the third shaft portion 2b of the rotary shaft 1 of the optical encoder only needs to be attached to the rotary shaft 22 of the motor 20 as required, there is no need to process the rotary shaft 22 of the motor 20 into the predetermined shape. . Therefore, an optical encoder including a rotary shaft 1 that can be attached to and detached from the rotary shaft 22 of the motor 20 and a code plate 6 including a mounting portion 4 and a disc portion 5 can be used independently of the motor system. .
[0020]
The effect of the optical encoder 10 will be described. In this optical encoder 10, first, the through-hole 7 for inserting the rotary shaft 1 is provided in the attachment portion 4 and the lid portion is not provided, so that the rotation shaft of the attachment portion 4 is not restricted by the lid portion. The attachment position (axial direction (thrust direction)) to 1 can be easily adjusted. Moreover, the code | cord | chord board which is a resin molding is made by making the outer diameter of the 2nd axial part 3 pinched | interposed into the 1st axial part 2a and the 3rd axial part 2b of the both ends of the rotating shaft 1 smaller than the internal diameter of a through-hole. The burr | flash formed in the attaching part 4 of 6 can be escaped, and stress concentration can be avoided. This can prevent the occurrence of cracks. Further, since the length of the first shaft portion 2a of the rotating shaft 1 is shorter than the length of the through-hole, the first shaft portion 2a of the rotating shaft 1 and the inside of the through-hole 7 of the mounting portion 4 are adjusted even when the mounting position is adjusted. Since the contact length can be kept constant, a stable fixed state can be obtained, and the surface runout of the disk portion can be suppressed. In addition, since the sum total of the length of the 1st axial part 2a and the length of the 2nd axial part 3 is longer than the length of the through-hole 7, even when the attachment position is adjusted with the upper end of the through-hole 7, the 2nd axial part 3 Can be adhered and fixed to the mounting portion 4. Further, the fillet shape of the adhesive 8 can be made almost constant. Furthermore, the adhesive strength can be improved by roughening the surface of the second shaft portion 3 of the rotating shaft 1 by machining or plasma processing. Since the attachment portion 4 is made of a transparent resin, a UV curable adhesive can also be used inside the through hole 7. By using a UV curable adhesive and irradiating with ultraviolet holes, stable adhesive strength can be secured in a short time.
[0021]
In this optical encoder 10, a first feature in which a through hole 7 is provided in the attachment portion 4, and a second feature in which a second shaft portion 3 having an outer diameter smaller than the inner diameter of the through hole 7 is provided in the rotating shaft 1. The relationship between these two features will be described. As shown in FIG. 4, in the code plate 6, a mounting portion 4 having a through hole 7 into which the rotary shaft 1 is inserted and a disc portion 5 are integrally formed of a transparent resin such as acrylic or polycarbonate. By providing the through hole 7 in the mounting portion 4 and not having the lid portion, the mounting position of the mounting portion 4 and the rotary shaft 1 can be easily adjusted. In the case of such a shape having a through hole, the gate 13 which is a resin injection port at the time of molding is arranged in a ring shape so that the resin flow is axially symmetric. Moreover, the gate 13 is normally provided in the position along the through-hole 7 of the attachment part 4 in order to make it easy to cut within a shaping die (FIG. 4A). Therefore, the burr | flash 14 is easy to be produced in the peripheral part of the through-hole 7 (FIG.4 (b)). When a conventional rotating shaft is inserted into the through-hole 7, it causes cracks due to stress concentration due to the biting of the peripheral burr 14. In this optical encoder 10, the second shaft portion 3 having an outer diameter smaller than the inner diameter of the through hole 7 is provided on the rotary shaft 1 inserted into the through hole 7. That is, when the rotating shaft 1 is inserted into the through hole 7, the burr can be released at the recessed portion of the second shaft portion 3 following the first shaft portion 2a. For this reason, stress concentration due to biting of burrs can be avoided, and the occurrence of cracks in the mounting portion 4 can be prevented.
[0022]
Embodiment 2. FIG.
A motor system with an optical encoder according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 5 is a schematic sectional view showing the arrangement of the code plate 6 and the light projecting / receiving unit 16 of the motor system 10a with an optical encoder. As compared with the motor system with an optical encoder according to the first embodiment, the optical encoder 10a includes a light projecting / receiving unit 16 including a light projecting unit and a light receiving unit on one side of the disc unit 5 of the code plate 6. It is different in that it is arranged. Further, the disk portion 5 of the code plate 6 is different in that a reflective layer 15 coated with Al, Au or the like that reflects light is provided. In this optical encoder 10 a, the light emitted from the light projecting / receiving unit 16 is modulated by a predetermined pattern of the disk unit 5, reflected by the reflecting layer 15, and received by the light projecting / receiving unit 16. Since light is reflected by one surface of the disc portion 5, an opaque resin plate may be used for the disc portion 5 instead of a transparent resin.
[0023]
In this optical encoder-equipped motor system 10a, since the light projecting unit and the light receiving unit are integrated into the light projecting / receiving unit 16, the configuration of the detection system can be simplified and the overall configuration of the optical encoder 10a can be reduced. it can.
[0024]
FIG. 6 is a schematic cross-sectional view of the shaft center showing the positional relationship when the rotating shaft 1 is attached to the rotating shaft 22 of the motor 20 in another motor system with an optical encoder. In this case, since the third shaft portion 2b of the rotary shaft 1 of the optical encoder only needs to be attached to the rotary shaft 22 of the motor 20 as required, there is no need to process the rotary shaft 22 of the motor 20 into the predetermined shape. . Therefore, an optical encoder including a rotary shaft 1 that can be attached to and detached from the rotary shaft 22 of the motor 20 and a code plate 6 including a mounting portion 4 and a disc portion 5 can be used independently of the motor system. .
[0025]
【The invention's effect】
According to the motor system with an optical encoder according to the present invention, the through-hole for inserting the rotation shaft of the motor is provided in the attachment portion of the code plate, and the lid portion is not provided, so that there is no restriction by the lid portion. The mounting position can be adjusted with. In addition, when the rotation shaft is inserted into the through hole by making the outer diameter of the second shaft portion sandwiched between the first shaft portion and the third shaft portion at both ends of the rotation shaft smaller than the inner diameter of the insertion hole. Moreover, the burr | flash produced around the through-hole of the code board which is a resin molding can be escaped to the recessed part of a 2nd axial part. Thereby, stress concentration due to biting of burrs can be avoided, and the occurrence of cracks can be prevented.
[0026]
Further, according to the motor system with an optical encoder according to the present invention, the first shaft portion of the rotating shaft has an axial length shorter than the length of the through hole. Even if it is moved in the direction (axial direction), the contact length between the first shaft portion of the rotating shaft and the inside of the through hole of the mounting portion can be kept constant. Thereby, a stable fixed state can be obtained.
[0027]
Furthermore, according to the motor system with an optical encoder according to the present invention, since the total length of the first shaft portion and the second shaft portion is longer than the length of the through hole, the mounting position is adjusted at the upper end of the through hole. In this case, the second shaft portion can be bonded and fixed to the attachment portion.
[0028]
Furthermore, according to the motor system with an optical encoder according to the present invention, since the transparent resin is used for the disk portion of the code plate, the light from the light projecting portion can be efficiently transmitted through the disk portion. Can do. Also, a UV curable adhesive can be used inside the through hole, and a stable adhesive strength can be secured in a short time by irradiation with ultraviolet light.
[0029]
Further, according to the motor system with an optical encoder according to the present invention, the reflecting plate for reflecting the light received from the light projecting portion is provided on the disc portion of the code plate. Therefore, the light projecting unit that irradiates light to the disk unit and the light receiving unit that receives the modulated light can be combined on one side of the disk unit, and the assembly of the detection unit becomes easy and the system configuration Can be reduced in size.
[0030]
Furthermore, the motor system with an optical encoder according to the present invention further includes a light projecting unit that irradiates the disc part with light and a light receiving unit that receives the light transmitted through the predetermined pattern. Thereby, the rotational speed of the motor can be detected.
[0031]
According to the optical encoder of the present invention, the through-hole for inserting the rotation shaft is provided in the attachment portion of the code plate and the lid portion is not provided, so that the attachment position is adjusted without being restricted by the lid portion. can do. In addition, when the rotation shaft is inserted into the through hole by making the outer diameter of the second shaft portion sandwiched between the first shaft portion and the third shaft portion at both ends of the rotation shaft smaller than the inner diameter of the insertion hole. Moreover, the burr | flash produced around the through-hole of the code board which is a resin molding can be escaped to the recessed part of a 2nd axial part. Thereby, stress concentration due to biting of burrs can be avoided, and the occurrence of cracks can be prevented. Since the third shaft portion at the other shaft end can be connected to the rotating shaft of the motor, it can be attached to and detached from the rotating shaft of the motor only when necessary.
[0032]
Further, according to the optical encoder of the present invention, since the transparent resin is used for the disk portion of the code plate, the light from the light projecting portion can be efficiently transmitted through the disk portion. Also, a UV curable adhesive can be used inside the through hole, and a stable adhesive strength can be secured in a short time by irradiation with ultraviolet light.
[0033]
Furthermore, according to the optical encoder according to the present invention, the reflecting plate for reflecting the light received from the light projecting portion is provided on the disc portion of the code plate. Therefore, the light projecting part for irradiating the disk part with light and the light receiving part for receiving the modulated light can be combined on one side of the disk part, making the detection part easy to assemble and the overall configuration Can be reduced in size.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view including an axis center showing an arrangement relationship between a code plate, a mounting portion, and a rotating shaft that constitute an optical encoder according to Embodiment 1 of the present invention.
FIG. 2 is a schematic diagram showing an arrangement of a light projecting unit and a light receiving unit of the optical encoder according to the first embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view of the shaft center showing the positional relationship when the rotating shaft is attached to the rotating shaft of the motor in another motor system with an optical encoder according to the first embodiment of the present invention.
4A is a schematic diagram of a code plate integrally formed with resin and a mounting portion before gate cutting in the motor system with an optical encoder according to the first embodiment of the present invention; FIG. These are the schematic diagrams after a gate cut.
FIG. 5 is a schematic diagram showing an arrangement of a light projecting unit and a light receiving unit of a motor system with an optical encoder according to a second embodiment of the present invention.
FIG. 6 is a schematic cross-sectional view of a shaft center showing an arrangement relationship when a rotating shaft is attached to a rotating shaft of a motor in another motor system with an optical encoder according to Embodiment 2 of the present invention.
FIG. 7 is a schematic cross-sectional view showing a configuration of a conventional optical encoder.
8A is a schematic diagram of a code plate integrally formed with a resin and a mounting portion before gate cutting in a conventional optical encoder, and FIG. 8B is a schematic diagram after gate cutting. .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotating shaft, 2a 1st axial part, 2b 3rd axial part, 3 2nd axial part, 4 attachment part, 5 disc part, 6 Code board, 7 Through-hole, 8 Adhesive 10, 10a With optical encoder Motor system, 11 Emitter, 12 Light receiver, 13 Gate, 14 burr, 15 Reflective layer, 16 Emitter / Receiver, 20 Motor, 22 Motor rotation shaft, 50 Optical encoder, 51 Rotation shaft, 54 Mounting portion, 55 yen Plate, 56 code plate, 58 Adhesive, 59 Lid, 63 Gate, 64 Barr

Claims (9)

A code plate comprising: a cylindrical mounting portion having a through hole in the center; and a disc portion extending outwardly in the radial direction from the mounting portion and having a predetermined pattern on the outer peripheral portion through which light received from outside is transmitted. ,
A motor having a rotating shaft to be inserted into the through hole, the first shaft portion of one shaft end having a first outer diameter substantially equal to the inner diameter of the through hole, and the first outer diameter; A second shaft portion having a small second outer diameter and adjacent to the first shaft portion, wherein the second shaft portion is fixed to the mounting portion with an adhesive at one opening portion of the through hole. A motor system with an optical encoder, comprising: a motor having a rotating shaft. 2. The motor system with an optical encoder according to claim 1, wherein the first shaft portion of the rotating shaft has an axial length shorter than a length of the through hole. 3. The optical system according to claim 2, wherein a sum of an axial length of the first shaft portion and an axial length of the second shaft portion of the rotating shaft is longer than a length of the through hole. Motor system with encoder. The motor system with an optical encoder according to claim 1, wherein a transparent resin plate is used as a disc portion of the code plate. 2. The motor system with an optical encoder according to claim 1, wherein the disk portion of the code plate is provided with a reflective layer that reflects light received from the light projecting portion. A light projecting portion for projecting light onto the pattern of the disc portion of the code plate;
The motor system with an optical encoder according to claim 1, further comprising a light receiving portion that receives light transmitted through the pattern of the disc portion of the code plate. A code plate comprising: a cylindrical mounting portion having a through hole in the center; and a disc portion extending outwardly in the radial direction from the mounting portion and having a predetermined pattern on the outer peripheral portion through which light received from outside is transmitted. ,
A rotary shaft to be inserted into the through hole, a first shaft portion of one shaft end having a first outer diameter substantially equal to the inner diameter of the through hole, and a second smaller than the first outer diameter A second shaft portion adjacent to the first shaft portion and a third shaft portion at the other shaft end attached to the rotating shaft of the motor, and in one opening portion of the through hole, The optical encoder, wherein the second shaft portion includes the attachment portion and a rotating shaft fixed with an adhesive. The optical encoder according to claim 7, wherein a transparent resin plate is used as a disc portion of the code plate. The optical encoder according to claim 7, wherein a reflection layer that reflects light received from the light projecting unit is provided on a disc portion of the code plate.

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