encoder

Abstract

To provide an encoder that can maintain high coaxial accuracy. [Solution] The encoder 1 includes a rotating shaft portion 11, a hub 12 fixed to the rotating shaft portion 11, and a disk 13 having a central hole the same size as or larger than the rotating shaft portion 11. The disk 13 is provided with an interaction surface portion that interacts with the detection unit, and the disk 13 is attached to and fixed to the hub 12.

Description

【Technical Field】 【0001】 This disclosure relates to an encoder. 【Background Art】 【0002】 Patent Document 1 discloses a rotary encoder that is easy to center a pulse disk and has little eccentricity, and a method for manufacturing the same. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent No. 5014512 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 As described in Patent Document 1, an encoder in which a disk having an interaction surface formed by chromium vapor deposition is press-fitted to a rotating shaft portion has been known. 【0005】 However, in the encoder described in Patent Document 1, when press-fitting, stress is applied to the interaction surface portion, causing distortion in the interaction surface portion, which may cause deterioration of the encoder coaxial accuracy. 【0006】 Therefore, an object of the present disclosure is to provide an encoder that can maintain high coaxial accuracy. 【Means for Solving the Problems】 【0007】 An encoder according to an aspect of the present disclosure includes: a rotating shaft portion, a hub fixed to the rotating shaft portion, and a disk having a central hole having the same diameter as or larger than that of the rotating shaft portion, wherein an interaction surface portion that interacts with a detection portion is provided on the disk, The disk is attached to and secured to the hub. [Effects of the Invention] 【0008】 According to the above, it is possible to provide an encoder that can maintain high coaxial accuracy. [Brief explanation of the drawing] 【0009】 [Figure 1] Figure 1 shows an example of an encoder related to this disclosure. [Figure 2A] Figure 2A is a diagram showing the assembly method of the encoder according to this disclosure. [Figure 2B] Figure 2B shows a diagram illustrating the assembly method of the encoder according to this disclosure. [Figure 2C] Figure 2C is a diagram showing the assembly method of the encoder according to this disclosure. [Figure 2D] Figure 2D is a diagram showing the assembly method of the encoder according to this disclosure. [Figure 3] Figure 3 shows another example of the encoder according to this disclosure. [Modes for carrying out the invention] 【0010】 [Details of the embodiments of this disclosure] Specific examples of encoders according to the embodiments of this disclosure will be described below with reference to the drawings. This disclosure is not limited to these examples, but is intended to include all modifications within the meaning and scope of the claims, as indicated by the claims. For convenience of explanation, the description of components having the same reference numerals as those already described in the description of the embodiments will be omitted. 【0011】 Figure 1 is a front view showing an encoder 1 according to an embodiment of this disclosure. In the embodiments described below, a reflective rotary encoder will be described. As shown in Figure 1, the encoder 1 includes a rotating shaft portion 11, a hub 12 fixed to the rotating shaft portion 11, an encoder disk 13, and an adhesive portion 14 that bonds the hub 12 and the encoder disk 13. The encoder 1 can detect the rotation status of the rotating shaft portion 11 by detecting a position detection pattern, which is an interaction surface portion 131 on the encoder disk 13 (described later), using a detection unit 50. 【0012】 The rotating shaft portion 11 is a shaft member that can rotate around the rotation axis K. The rotating shaft portion 11 may be, for example, the motor shaft of a servo motor, or it may be a rotating shaft connected to the motor shaft. 【0013】 The hub 12 is a disc-shaped member for attaching the encoder disc 13 to the rotating shaft portion 11. The hub 12 has a central hole 12H in its center, and the hub 12 is fixed to the rotating shaft portion 11 by inserting the rotating shaft portion 11 into the central hole 12H. More specifically, the hub 12 is fixed to the rotating shaft portion 11 by press-fitting the rotating shaft portion 11 into the central hole 12H. It is preferable that the central hole 12H of the hub 12 be a crimping hole for the rotating shaft portion 11 so that the hub 12 is firmly fixed. In other words, before the hub 12 is press-fitted into the rotating shaft portion 11, it is preferable that the inner diameter of the central hole 12H is the same as or slightly smaller than the outer diameter of the rotating shaft portion 11. 【0014】 The encoder disc 13 is a sheet-like member provided to enable detection of the rotational state of the rotating shaft portion 11. The encoder disc 13 is made of, for example, a resin film, and at least a portion of it is made of a magnetic material to improve ease of assembly in the assembly process described later. The encoder disc 13 has an interaction surface portion 131 on which a position detection pattern is formed, an adhesive surface portion 132 to which it is bonded to the hub 12, and a disk central hole 13H. In this embodiment, it is preferable that the encoder disc 13 is flexible. 【0015】 The interaction surface 131 is provided with a position detection pattern. The position detection pattern provided on the interaction surface 131 is, for example, a linear pattern formed at equal intervals in the circumferential direction by means of chromium evaporation or the like. In the present embodiment, on the interaction surface 131, reflecting surfaces and non-reflecting surfaces are alternately arranged at equal intervals. The position detection pattern is configured to be readable by a detection unit 50 including a light-emitting element 51 and a light-receiving element 52 as shown in FIG. 1, for example. In the example shown in FIG. 1, the detection unit 50 can detect the rotation state such as the position (phase), rotation direction, rotation speed, and angular acceleration of the encoder disk 13 by detecting the light emitted from the light-emitting element 51 and reflected by the position detection pattern on the interaction surface 131 with the light-receiving element 52. Note that the encoder 1 according to the present disclosure may include the detection unit 50, or the detection unit 50 may be provided outside the encoder 1. 【0016】 The adhesion surface 132 is provided with an adhesion portion 14 capable of adhering the hub 12 and the encoder disk 13. In the present embodiment, the adhesion portion 14 is a double-sided tape attached to the adhesion surface 132. Note that the configuration of the adhesion portion 14 is not limited to this, and for example, an adhesive or a molten resin may be used. 【0017】 The disk center hole 13H of the encoder disk 13 has a diameter equal to or larger than the diameter of the rotation shaft portion 11. That is, the encoder disk 13 is not directly fixed to the rotation shaft portion 11. The encoder disk 13 is fixed to the hub 12 via the adhesion portion 14. 【0018】 <Assembly method of the encoder> Next, the assembly method (manufacturing method) of the encoder 1 according to the present embodiment will be described with reference to FIGS. 2A to 2D. FIGS. 2A to 2D are diagrams showing the assembly method of the encoder 1 according to the present embodiment. 【0019】 The assembly process for encoder 1 will be described in detail. First, as shown in Figure 2A, the hub center hole 12H is press-fitted into the rotating shaft portion 11 to fix the hub 12. Since the hub center hole 12H and the rotating shaft portion 11 are fixed by a pressure fit, the hub 12 is firmly fixed to the rotating shaft portion 11. 【0020】 Next, the encoder disc 13 to be attached to the hub 12 is picked up by the jig 100. The jig 100 uses a magnet 1011 provided at the end of the cylindrical portion 101 to attract the encoder disc 13. Figure 2A shows the jig 100 after the encoder disc 13 has been picked up. The encoder disc 13 is attracted by the jig 100 so that the adhesive portion 14 is exposed. 【0021】 In this embodiment, the encoder disk 13 is bonded using a dedicated rod-shaped jig 100 shown in Figure 2A. The jig 100 can hold the encoder disk 13 to its end, align it with the rotating shaft portion 11, and then bond it to the hub 12. 【0022】 The jig 100 has a cylindrical portion 101 and a shaft portion 102 provided at the center of the cylindrical portion 101. The cylindrical portion 101 and the shaft portion 102 are configured to be displaceable relative to each other along the longitudinal direction D of the shaft portion 102. 【0023】 The cylindrical portion 101 has a magnet portion 1011 at one end along its longitudinal direction D. The magnet portion 1011 is provided on the surface of one end of the cylindrical portion 101. Since at least a portion of the encoder disk 13 according to this embodiment is made of a magnetic material, the cylindrical portion 101 can attract the encoder disk 13 by the magnetic force of the magnet portion 1011. The magnetic force of the magnet portion 1011 is configured to be weaker than the adhesive force between the adhesive surface portion 132 of the encoder disk 13 and the hub 12. The magnet portion 1011 may be provided anywhere as long as it can attract the encoder disk 13 to one end of the cylindrical portion 101. 【0024】 The shaft portion 102 has a tip portion 1021 at the end of the cylindrical portion 101 on the side where the magnet portion 1011 is provided. The tip portion 1021 is shaped to fit into the position adjustment hole 11H provided in the rotating shaft portion 11. When assembling the encoder 1, the tip portion 1021 of the jig 100 can be fitted into the position adjustment hole 11H of the rotating shaft portion 11 to align the jig 100 with the rotating shaft portion 11. 【0025】 The outer diameter of the shaft portion 102 is slightly smaller than the central hole 13H of the encoder disk 13. Therefore, even when the encoder disk 13 is attached to the jig 100, no load is placed on the encoder disk 13. Furthermore, when the encoder disk 13 is attached to the jig 100, the shaft portion 102 and the central hole 13H come into contact, thereby determining the in-plane position of the encoder disk 13 (the direction perpendicular to the rotation axis K). In other words, when the encoder disk 13 is attached to the jig 100, the encoder disk 13 is positioned relative to the jig 100. 【0026】 Next, as shown in Figure 2B, the jig 100 is moved so that its tip 1021 fits into the position adjustment hole 11H of the rotating shaft 11. At this time, the position of the shaft 102 of the jig 100 and the rotating shaft 11 is adjusted by fitting the tip 1021 so that there is no misalignment between the shaft 102 of the jig 100 and the rotating shaft 11. 【0027】 Next, as shown in Figure 2C, with the tip portion 1021 of the jig 100 fitted into the position adjustment hole 11H, the cylindrical portion 101 is displaced relative to the shaft portion 102. This allows the encoder disc 13 to be moved relative to the shaft portion 102, bringing it closer to and into contact with the hub 12. The encoder disc 13, once in contact with the hub 12, is bonded to the hub 12 by the adhesive portion 14. 【0028】 Finally, as shown in Figure 2D, the jig 100 is moved away from the rotating shaft 11 and the hub 12. The encoder disk 13 is bonded to the hub 12, and its adhesive force is stronger than the magnetic force of the jig 100. Therefore, the encoder disk 13 remains bonded to the hub 12, while only the jig 100 can be moved away from the rotating shaft 11 and the hub 12. As mentioned earlier, the encoder disk 13 is positioned relative to the jig 100 by the contact between the shaft 102 and the disk's central hole 13H, and the jig 100 is positioned relative to the rotating shaft 11. For this reason, by moving the encoder disk 13 from the jig 100 to the rotating shaft 11 along the rotation axis K while the magnet 1011 pulls the encoder disk 13 towards the jig 100, the encoder disk 13 can be moved while maintaining its position perpendicular to the rotation axis K. Thus, the encoder disk 13 can be positioned relative to the rotating shaft 11. The encoder 1 according to this embodiment can be assembled by the above steps. 【0029】 In order to accurately detect the rotation of the rotating shaft, the encoder disc and hub of the encoder must maintain high coaxial accuracy. In other words, in an encoder, it is preferable that the rotation axes of the rotating shaft, encoder disc and hub are aligned in order to maintain high coaxial accuracy. 【0030】 Conventional encoders have a configuration in which the encoder disc is attached to a hub, and then the integrated unit is attached to the rotating shaft; in other words, the encoder disc is attached via the hub. However, with the above configuration, positional adjustment (axis adjustment) between the encoder disc and the hub, and positional adjustment (axis adjustment) between the integrated unit and the rotating shaft are required, and there were issues with coaxial accuracy. In the encoder described in Patent Document 1, an attempt is made to improve coaxial accuracy by attaching the encoder disc to a hub attached to the rotating shaft, but because the encoder disc is press-fitted onto the rotating shaft, there is a risk of distortion in the encoder disc, and there is still room for improvement in coaxial accuracy. 【0031】 According to the encoder 1 of this disclosure, since the encoder disk 13 is attached to a hub 12 fixed to the rotating shaft portion 11, the encoder disk 13 can be positioned relative to the rotating shaft portion 11 without using the hub 12. As a result, the coaxial accuracy is higher compared to a configuration in which the encoder disk 13 is attached via the hub 12. 【0032】 Furthermore, the central hole 13H of the disk is larger in diameter than the diameter of the rotating shaft portion 11, and the encoder disk 13 is fixed by adhesive rather than press-fitting. As a result, no pressure is applied to the interaction surface of the encoder disk 13. With the above configuration, the occurrence of distortion of the encoder disk 13 caused by pressure on the encoder disk 13 can be suppressed, and thus the coaxial accuracy of the encoder 1 can be kept high. 【0033】 Although embodiments of the present disclosure have been described above, the encoder 1 according to the present disclosure is not limited thereto. For example, the encoder 1 according to the present disclosure can also be configured as a transparent rotary encoder as shown in Figure 3. Figure 3 shows another example of the encoder 1 according to this disclosure. The encoder 1A has a rotating shaft portion 11A, a hub 12A, and an encoder disk 13A, and except for the encoder disk 13A, it has the same configuration as the encoder 1 according to the embodiment described above. 【0034】 In the example shown in Figure 3, the encoder disk 13A has an adhesive surface portion 132A that is bonded to the hub 12A, and an interaction surface portion 131A located radially outward from the adhesive surface portion 132A and provided with a position detection pattern. On the encoder disk 13A, the interaction surface portion 131A and the adhesive surface portion 132A are located on the same surface. The detection unit 50 shown in Figure 3 can detect the rotation state of the rotating shaft portion 11A by detecting the position detection pattern provided on the interaction surface portion 131A located radially outward. The encoder disk 13A is fixed to the hub 12A via the adhesive portion 14A in the same manner as in the embodiment described above. With such a configuration, it is possible to improve coaxial accuracy even in a through-type rotary encoder. Furthermore, although the embodiments described above illustrate the application of the present disclosure to an optical encoder, the present invention is not limited thereto. The present disclosure may also be applied to a magnetic encoder in which north poles and south poles are regularly arranged on the interaction surface. 【0035】 While embodiments of this disclosure have been described above, it goes without saying that the technical scope of this disclosure should not be interpreted restrictively by the description of these embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications to the embodiments are possible within the scope of the invention described in the claims. The technical scope of this disclosure should be determined based on the scope of the invention described in the claims and the scope of its equivalents. [Explanation of Symbols] 【0036】 1.1A encoder 11,11A Rotating shaft section 11H Position adjustment hole 12,12A hub 12H hub center hole 13,13A Encoder Disk 13H disk center hole 14,14A Adhesive part 50 Detection unit 51 Light-emitting element 52 Photodetector 100 fixtures 101. Cylindrical section 102 Shaft 131,131A Interacting Face 132,132A Next face 1011 Magnet Department 1021 tip

Claims

[Claim 1] Rotating shaft and, The hub fixed to the aforementioned rotating shaft, It has a disk having a central hole that is the same diameter as or larger than the aforementioned rotating shaft portion, The disk is provided with an interaction surface that interacts with the detection unit. An encoder in which the disk is attached to and fixed to the hub. [Claim 2] The encoder according to claim 1, wherein at least a portion of the back surface of the interaction surface is an adhesive surface that is attached to the hub. [Claim 3] The encoder according to claim 1, wherein the interaction surface and the adhesive surface attached to the hub are provided on the same surface, and the interaction surface is provided radially outward from the adhesive surface. [Claim 4] The encoder according to claim 1, wherein the disk is a flexible sheet-like member. [Claim 5] A method for manufacturing an encoder in which a disk having an interaction surface portion that interacts with a detection portion is fixed to a rotating shaft portion via a hub, The hub is press-fitted into the rotating shaft portion. A method for manufacturing an encoder, comprising attaching the disc to the press-fitted hub. [Claim 6] The disk has an adhesive surface portion that is attached to the hub, At least a portion of the disk is made of a magnetic material, The disk is picked up by a jig that has attracted the disk from the back surface of the adhesive surface by magnetic force, The method for manufacturing an encoder according to claim 5, wherein the jig is pressed toward the hub so that the adhesive surface portion is attached to the hub.

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