Encoder, motor, and encoder adjustment method

Abstract

The encoder includes a rotating disk, a protrusion provided coaxially with the shaft at one end of the shaft, and a boss supporting the rotating disk between the rotating disk and the one end of the shaft. A through hole having a screw thread is formed on an inner peripheral surface of the boss. After the boss is engaged with the protrusion of the shaft, an adjustment tool is passed through an opening formed in the rotating disk and screwed into the through hole of the boss, and the position of the boss on the central axis of the shaft is adjusted using the adjustment tool.

Description

[Technical field]

[0001] The present disclosure relates to an encoder, a motor, and an encoder adjustment method. [Background technology]

[0002] Encoders are used to detect the number of rotations of a rotating body, for example, the output shaft of a motor. An optical encoder includes a light source, a light receiving unit, and a rotating disk arranged between the light source and the light receiving unit (see, for example, Patent Document 1 and Patent Document 2). As is well known, the rotating disk in which a number of slits are formed is arranged coaxially with the rotating body, or arranged to rotate synchronously with the rotating body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 04-063020 [Patent Document 2] JP 2012-141248 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to improve the detection accuracy of the encoder, it is necessary to maintain an appropriate and constant gap between the rotating disk and the light receiving unit, and to suppress the variation in the height of the rotating disk. Furthermore, it is also necessary to simplify the configuration of the encoder and reduce its weight.

[0005] There is a demand for an encoder, a motor, and an encoder adjustment method that have a simple configuration and that can improve detection accuracy. [Means for solving the problem]

[0006] According to a first aspect of the present disclosure, there is provided an encoder comprising: a rotating disk having at least one slit that transmits light output from a light source; a protrusion provided coaxially with a shaft at one end of a shaft that should rotate integrally with the rotating disk; and a boss disposed between the rotating disk and the one end of the shaft and supporting the rotating disk, wherein a through hole having a thread formed on an inner peripheral surface of the boss is formed coaxially with the shaft; and after the boss is engaged with the protrusion of the shaft, an adjustment tool is passed through an opening formed in the rotating disk and screwed into the through hole of the boss, and the position of the boss on the central axis of the shaft is adjusted using the adjustment tool.

[0007] The objects, features and advantages of the present disclosure will become more apparent from the following description of the embodiments taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0008] [Figure 1] 1 is an axial cross-sectional view of a motor equipped with an encoder according to the present disclosure; [Diagram 2] 1 is an axial cross-sectional view of an encoder according to a first embodiment. [Figure 3A] FIG. 2 is a first partial axial cross-sectional view of the encoder; [Figure 3B] FIG. 4 is a second partial axial cross-sectional view of the encoder; [Figure 3C] FIG. 4 is a third partial axial cross-sectional view of the encoder; [Figure 3D] FIG. 4 is a fourth axial partial cross-sectional view of the encoder; [Figure 3E] FIG. 13 is a fifth axial partial cross-sectional view of the encoder. [Figure 3F] 3A to 3E are flowcharts showing the processes of the embodiments. [Figure 4] FIG. 11 is a partial axial cross-sectional view of an encoder according to a second embodiment. [Diagram 5] FIG. 10 is a partial axial cross-sectional view of an encoder according to a third embodiment. [Figure 6]FIG. 1 is an axial cross-sectional view of an encoder according to a conventional technique. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings, in which corresponding components are designated by common reference numerals throughout the drawings. FIG. 1 is an axial cross-sectional view of a motor with an encoder according to the present disclosure. As shown in FIG. 1, the motor 1 includes a stator 9 and a rotor 10 rotatably supported by the stator 9. A first bearing 7 and a second bearing 8 are disposed on the inner peripheral surface of the stator 9. A shaft 5 penetrating the rotor 9 is rotatably supported by the stator 9 by the first bearing 7 and the second bearing 8. An encoder 6 for detecting the number of rotations of the shaft 5 is attached to one end of the stator 9. The encoders 6, 6a, 6b, and 6c attached to the shaft 5 of the motor 1 will be described below, but the encoder 6 and the like may be attached to a rotating body other than the shaft 5 of the motor 1.

[0010] 2 is an axial cross-sectional view of the encoder according to the first embodiment. The encoder 6a mainly includes a bottomed housing 11, a lid 12 that engages with the housing 11, a rotating disk 20 disposed between the housing 11 and the lid 12, and a boss 30 that connects the rotating disk 20 to the shaft 5.

[0011] As can be seen from FIG. 2, an opening is formed in the bottom of the housing 11. A light source 28 is disposed in the bottom of the housing 11, and a light receiving unit 29 is disposed on the inner surface of the lid 12 at a position corresponding to the light source 28. The positional relationship between the light source 28 and the light receiving unit 29 may be reversed. Also, the encoder 6a does not necessarily include the housing 11 and the lid 12. Also, as is well known, the rotating disk 20 has at least one slit 25 formed in its radial direction. The light output from the light source 28 reaches the light receiving unit 29 through the at least one slit 25.

[0012] A protrusion 4 is provided at the tip of the shaft 5 coaxially with the shaft 5. The protrusion 4 is preferably cylindrical with a diameter smaller than that of the shaft 5. A boss 30 is engaged around the protrusion 4.

[0013] The boss 30 includes a support portion 31 that supports one surface of the rotating disk 20, and an enclosing portion 32 that extends from the support portion 31 and encloses the outer circumferential surface of the protruding portion 4. Strictly speaking, the enclosing portion 32 of the boss 30 is press-fitted into the protruding portion 4, so that the boss 30 engages with the protruding portion 4 of the shaft 5. The boss 30 is preferably formed from a metal or a hard resin. The height of the enclosing portion 32 at the central axis O of the shaft 5 is preferably greater than the height of the protruding portion 4. The lower end of the enclosing portion 32 can abut against the end surface of the shaft 5.

[0014] 2, in order to support the lower surface of the rotating disk 20, the diameter of the support portion 31 is preferably larger than the diameter of the surrounding portion 32. An opening 21 is formed in the center of the rotating disk 20, and a through hole 33 is formed in the center of the support portion 31 of the boss 30. The opening 21 and the through hole 33 are preferably coaxial with the central axis O of the shaft 5. In addition, the diameter of the opening 21 is preferably larger than the diameter of the through hole 33. As will be described later, a screw thread is formed on the inner peripheral surface of the through hole 33 of the boss 30.

[0015] Figures 3A to 3E are partial cross-sectional views of the encoder in the axial direction, and Figure 3F is a flowchart showing the processing of Figures 3A to 3E. Hereinafter, the position adjustment of the boss 30 and / or the rotating disk 20 in the encoder of the present disclosure will be described with reference to Figures 3A to 3F. At least one of the multiple steps described below may be performed by an operator, or may be automatically performed by a single or multiple articulated robots.

[0016] 3A, the rotating disk 20 is fixed to the upper surface of the support portion 31 of the boss 30 so that the central axis O of the rotating disk 20 is coaxial with the through hole 33. As a result, the rotating disk 20 and the boss 30 become integrated.

[0017] Next, the surrounding portion 32 of the boss 30 is engaged with the protruding portion 4 of the shaft 5. The inner peripheral surface of the surrounding portion 32 and the outer peripheral surface of the protruding portion 4 have the same shape. Then, the surrounding portion 32 is press-fitted into the protruding portion 4 until the lower end of the surrounding portion 32 reaches one end of the shaft 5 (step S11). Note that a visual sensor (not shown) disposed on the side of the shaft may be used to determine whether the lower end of the surrounding portion 32 has reached one end of the shaft 5.

[0018] Next, as shown in FIG. 3B, the adjustment tool 39 is inserted into the through hole 33 of the boss 30 through the through hole 33 of the rotary disk 20. The adjustment tool 39 is a bolt or a screw having a thread formed on the outer circumferential surface of its shaft. Alternatively, a rod having a thread formed on its outer circumferential surface may be used as the adjustment tool 39. As shown in FIG. 3C, a thread is formed on the inner circumferential surface of the through hole 33, so that the adjustment tool 39 screws into the through hole 33. Then, the adjustment tool 39 is rotated in a predetermined direction A1, for example, in the clockwise direction (step S12).

[0019] The adjustment tool 39 continues to rotate until the tip of the adjustment tool 39 reaches the end face of the protrusion 4. Whether or not the tip of the adjustment tool 39 has reached the end face of the protrusion 4 may be determined, for example, through a torque sensor (not shown) provided on the hand of the articulated robot. In this case, when the torque detected by the torque sensor exceeds a predetermined value, it can be determined that the tip of the adjustment tool 39 has reached the end face of the protrusion 4 (step S13).

[0020] 3D, measuring device 61 is disposed so as to face the outer circumferential surface of surrounding portion 32 of boss 30. In FIG. 3D, measuring device 61 is provided on the end surface of stator 9, but measuring device 61 may be provided in other locations.

[0021] The measuring device 61 measures the height T of the rotating disk 20 integral with the boss 30. In other words, the height T is the distance between the rotating disk 20 and the end face of the stator 9. Alternatively, the height T may be the distance between the boss 30 and the end face of the stator 9. In the present disclosure, the positions of the boss 30 and the rotating disk 20 on the central axis of the shaft are adjusted by adjusting the height T.

[0022] 3D includes a plurality of photoelectric sensors 62 arranged in parallel to the central axis of the shaft 5. The light projection directions of the plurality of photoelectric sensors 62 are perpendicular to the central axis of the shaft 5. The height T described above is measured from the positions of the photoelectric sensors where the light projected from the plurality of photoelectric sensors 62 is blocked by the rotating disc 20. Although not shown in the drawing, the measurement device 61 may include a plurality of light receiving elements arranged opposite each of the plurality of photoelectric sensors 62.

[0023] Alternatively, a distance sensor may be used as the measuring device 61. In this case, the measuring direction of the distance sensor is arranged perpendicular to the surface of the rotating disk 20 and the end face of the stator 9. Then, the height T described above is measured by subtracting the distance between the distance sensor and the surface of the rotating disk 20 from the distance between the distance sensor and the end face of the stator 9, which is measured in advance. Naturally, measuring devices 61 with other configurations may be used.

[0024] As shown in Fig. 3D, while measuring the height T with the measuring device 61, the adjustment tool 39 is rotated in a predetermined direction A1 (step S14). As a result, the boss 30 and the rotating disk 20 move in a direction away from the stator 9. Since the lower end of the adjustment tool 39 abuts against the protruding portion 4, the boss 30 and the rotating disk 20 move upward in the direction of the arrow A2. As a result, a gap is formed between the lower end of the surrounding portion 32 and the end face of the shaft 5 as shown in Fig. 3D.

[0025] With regard to the height T, an ideal height T0 is obtained in advance by an experiment, a simulation, or the like. When the height T reaches the ideal height T0 while the adjustment tool 39 is being rotated in the predetermined direction A1, the rotation of the adjustment tool 39 is stopped (step S15). This completes the position adjustment of the boss 30 and the rotating disk 20 on the central axis O of the shaft 5.

[0026] 3E, the adjustment tool 39 is rotated in another predetermined direction A3, for example, counterclockwise (step S16). As a result, the ideal height T0 is maintained by the boss 30 and the rotating disc 20, and only the adjustment tool 39 moves away from the protrusion 4. Finally, the adjustment tool 39 is released from the boss 30 (step S17).

[0027] In this way, the final encoder 6a etc. in the present disclosure does not include the adjustment tool 39. For this reason, it is possible to simplify the configuration of the encoder 6a etc. and reduce the weight of the encoder 6a etc.

[0028] Incidentally, Fig. 6 is an axial cross-sectional view of a conventional encoder. In the encoder 6' shown in Fig. 6, the position of the encoder may be adjusted by simply pressing the boss 30 into the protruding portion 4 with the rotating disk 20 fixed to the boss 30, thereby causing the lower end of the surrounding portion 32 to reach one end of the shaft 5.

[0029] In this case, however, the positions of the boss 30 and the rotating disk 20 are affected by the dimensional tolerances of the shaft 5, the stator 9, the boss 30, the rotating disk 20, etc. Therefore, there is a large variation in the height of the rotating disk 20, and the interpolation accuracy is not stable.

[0030] Also, in the encoder 6' shown in FIG. 6, with the rotating disk 20 fixed to the boss 30, the boss 30 is pressed into the protrusion 4 while measuring the height T, and when the ideal height is reached, the pressing of the boss 30 is stopped, thereby adjusting the encoder.

[0031] However, in this case, the surrounding portion 32 of the boss 30 does not reach one end of the shaft 5. Therefore, there is a possibility that the rotating disk 20 may be fixed at an angle from a plane perpendicular to the central axis of the shaft 5, and therefore, a situation may occur in which the rotating disk 20 experiences surface wobble.

[0032] In this regard, in the present disclosure, since the through hole 33 is formed in the boss 30, it is possible to raise the boss 30 and the rotating disk 20 to the ideal height T0 using the adjuster 39 after the lower end of the surrounding portion 32 reaches one end of the shaft 5. Therefore, the above-mentioned problem does not occur in the present disclosure. In other words, in the present disclosure, it is possible to provide an encoder 6a that suppresses the variation in the height of the rotating disk 20 and has stable interpolation accuracy. Furthermore, in the present disclosure, the rotating disk 20 can be fixed to a surface perpendicular to the central axis of the shaft 5, and it is also possible to suppress the surface wobble of the rotating disk 20.

[0033] With this configuration, in the present disclosure, the gap between the rotating disk 20 and the light receiving portion 29 can be maintained appropriately and constantly, and therefore the detection accuracy of the encoder 6a can be improved.

[0034] Fig. 4 is a partial axial cross-sectional view of an encoder according to a second embodiment. In the encoder 6b shown in Fig. 4, two through holes 33a, 33b are formed in the support portion 31 of the boss 30. These through holes 33a, 33b extend parallel to the central axis of the shaft 5 in the region inside the surrounding portion 32. The inner peripheral surfaces of these through holes 33a, 33b are formed with threads similar to those described above. Adjusters 39a, 39b are screwed into these through holes 33a, 33b, respectively. The adjusters 39a, 39b function in the same manner as the adjuster 39 described above, but the diameters of the adjusters 39a, 39b may be smaller than the diameter of the adjuster 39.

[0035] In this case, the positions of the rotating disk 20 and the boss 30 on the central axis O of the shaft 5 are adjusted in the same manner as described above. In the second embodiment, in addition to adjusting the height T of the rotating disk 20 and the boss 30, it is possible to adjust the height of the rotating disk 20 so as to further suppress the in-plane variation of the rotating disk 20. For this purpose, it is preferable that the adjusters 39a and 39b are not in contact with each other. Note that the use of three or more adjusters is also included in the scope of the present disclosure, and in such a case, it will be understood that the in-plane variation of the height of the rotating disk 20 can be suppressed more precisely.

[0036] 5 is a partial axial cross-sectional view of an encoder according to a third embodiment. In an encoder 6c shown in FIG. 5, a cylindrical recess 34 is formed on an end face of a protruding portion 4. A screw thread is formed on an inner peripheral surface of the recess 34. However, the diameter of the recess 34 is smaller than the diameter of the through hole 33.

[0037] Another adjuster 38 screws into the recess 34. The other adjuster 38 is a bolt or screw with a thread formed on the outer circumferential surface of its shaft. The diameter of the shaft of the other adjuster 38 is smaller than the diameters of the shafts of the adjuster 39, etc. However, the diameter of the head of the other adjuster 38 is larger than the diameter of the through hole 33.

[0038] In the third embodiment, as described with reference to Fig. 3F etc., the positions of the rotary disk 20 and the boss 30 are adjusted using the adjuster 39. Then, if it is found in steps S14 to S15 of Fig. 3F that the height T is greater than the ideal height T0, the adjuster 39 is rotated in another predetermined direction A3, for example, counterclockwise, to remove the adjuster 39 from the encoder 6c.

[0039] Next, the other adjuster 38 is passed through the through hole 33 and screwed into the recess 34 of the protrusion 4. When the other adjuster 38 is then rotated in a predetermined direction A1, for example, clockwise, the rotating disc 20 and the boss 30 move toward the shaft 5 together with the other adjuster 38.

[0040] As described above, the height T is measured by the measuring device 61, and when the height T falls to the ideal height T0, the rotation of the other adjusting tool 38 is stopped and the other adjusting tool 38 is rotated in another predetermined direction A3, for example, counterclockwise, to remove the other adjusting tool 38. It will be understood that this allows readjustment even if the height T becomes larger than the ideal height T0.

[0041] At least one of the embodiments described above has the advantage of being able to provide an encoder with a simple configuration that can improve detection accuracy.

[0042] Although the embodiments of the present disclosure have been described in detail, the present disclosure is not limited to the above-mentioned individual embodiments. Various additions, replacements, modifications, partial deletions, etc. are possible for these embodiments within the scope of the gist of the invention, or within the scope of the idea and intent of the present invention derived from the contents described in the claims and their equivalents. For example, in the above-mentioned embodiments, the order of each operation and the order of each process are shown as examples, and are not limited to these. The same applies when numerical values ​​or formulas are used in the description of the above-mentioned embodiments. Furthermore, appropriate combinations of some of the above-mentioned embodiments are included in the scope of the present disclosure.

[0043] The following supplementary notes are further disclosed regarding the above-described embodiments and modifications. (Appendix 1) a rotating disk having at least one slit for transmitting light output from a light source; a protrusion provided coaxially with a shaft at one end of the shaft to be rotated integrally with the rotary disk; a boss disposed between the rotating disk and the one end of the shaft and supporting the rotating disk; a through hole having a screw thread formed in an inner peripheral surface of the boss and coaxial with the shaft; An encoder in which, after the boss is engaged with the protruding portion of the shaft, an adjustment tool is passed through an opening formed in the rotating disk and screwed into the through hole of the boss, and the position of the boss on the central axis of the shaft is adjusted using the adjustment tool. (Appendix 2) 2. The encoder according to claim 1, wherein the position of the boss is adjusted after a tip of the adjustment tool is brought into contact with an end face of the protrusion. (Appendix 3) 2. The encoder of claim 1, wherein the adjustment tool is removed from the boss after the position of the boss is adjusted. (Appendix 4) 2. The encoder of claim 1, wherein the opening and the through hole are formed coaxially with the central axis of the shaft. (Appendix 5) The boss has a plurality of through holes formed therein, 2. The encoder of claim 1, further comprising: a plurality of adjustment tools that are passed through the opening of the rotating disk and screwed into each of the plurality of through holes of the boss, and the plurality of adjustment tools are used to adjust the position of the boss on the central axis of the shaft and the position of the rotating disk relative to a plane perpendicular to the central axis. (Appendix 6) 2. The encoder of claim 1, wherein a recess is formed in an end face of the protrusion coaxially with a central axis of the shaft. (Appendix 7) 2. A motor equipped with an encoder as described in claim 1. (Appendix 8) A boss is provided, the boss having an enclosing portion and a supporting portion, the supporting portion being provided with a through hole having a thread formed on an inner peripheral surface thereof; A rotary disk is supported on the support portion of the boss, so that an opening portion formed in the rotary disk and a through hole of the boss are coaxial with each other; Engaging the surrounding portion of the boss with a protrusion provided coaxially on one end of the shaft; an adjustment tool is passed through the opening of the rotary disk and screwed into the through hole of the boss; An encoder adjustment method, comprising: adjusting a position of the boss on a central axis of the shaft using the adjustment tool. (Appendix 9) 9. The encoder adjusting method according to claim 8, further comprising adjusting a position of the boss after a tip of the adjustment tool is brought into contact with an end face of the protrusion. (Appendix 10) 9. The encoder adjusting method according to claim 8, further comprising removing the adjustment tool from the boss after adjusting the position of the boss. [Explanation of symbols]

[0044] 1 Motor 4 Protrusion 5 Shaft 6, 6a~6c Encoders 9 Stator 10 Rotor 11. Housing 12 Lid 20 Rotating Disc 25 Slit 28 light source 29 Light receiving section 30 Boss 31 Support part 32 Encirclement 33, 33a, 33b through hole 38 Other Adjustment Tools 39, 39a, 39b adjustment tool 61 Measuring Equipment 62 Photoelectric Sensor

Claims

1. a rotating disk having at least one slit for transmitting light output from a light source; a protrusion provided coaxially with a shaft at one end of the shaft to be rotated integrally with the rotary disk; a boss disposed between the rotating disk and the one end of the shaft and supporting the rotating disk; a through hole having a screw thread formed in an inner peripheral surface of the boss and coaxial with the shaft; An encoder in which, after the boss is engaged with the protruding portion of the shaft, an adjustment tool is passed through an opening formed in the rotating disk and screwed into the through hole of the boss, and the position of the boss on the central axis of the shaft is adjusted using the adjustment tool.

2. 2. The encoder according to claim 1, wherein the position of the boss is adjusted after a tip of the adjustment tool is brought into contact with an end face of the protruding portion.

3. 2. The encoder of claim 1, wherein the adjustment tool is removed from the boss after the position of the boss is adjusted.

4. The encoder according to claim 1 , wherein the opening and the through hole are formed coaxially with the central axis of the shaft.

5. The boss has a plurality of through holes formed therein, 2. The encoder of claim 1, further comprising: a plurality of adjustment tools that are threaded through the opening of the rotating disk and into each of the plurality of through holes of the boss, and the plurality of adjustment tools are used to adjust the position of the boss on a central axis of the shaft and the position of the rotating disk relative to a plane perpendicular to the central axis.

6. The encoder according to claim 1 , wherein a recess is formed in an end face of the protrusion coaxially with a central axis of the shaft.

7. A motor having the encoder of claim 1 attached thereto.

8. A boss is provided, the boss having an enclosing portion and a supporting portion, the supporting portion being provided with a through hole having a thread formed on an inner peripheral surface thereof; A rotary disk is supported on the support portion of the boss, so that an opening portion formed in the rotary disk and a through hole of the boss are coaxial with each other; Engaging the surrounding portion of the boss with a protrusion provided coaxially with the shaft at one end of the shaft; an adjustment tool is passed through the opening of the rotary disk and screwed into the through hole of the boss; An encoder adjustment method, comprising: adjusting a position of the boss on a central axis of the shaft using the adjustment tool.

9. 9. The encoder adjusting method according to claim 8, further comprising the step of adjusting the position of the boss after the tip of the adjusting tool is brought into contact with the end face of the protruding portion.

10. 9. The method for adjusting an encoder according to claim 8, further comprising the step of removing the adjusting tool from the boss after adjusting the position of the boss.