Encoder

Abstract

An encoder according to the present disclosure comprises: a moving body; a detection unit; a substrate; and a coating film. The detection unit detects the amount of movement of the moving body. For example, the detection unit has a function of detecting a change in magnetic field or in light quantity associated with movement of the moving body in order to detect the amount of movement of the moving body. The detection unit is mounted on the surface of the substrate. The coating film covers the surface of the substrate together with the detection unit, and is tightly attached to the surface of the substrate and the surface of the detection unit. A recess and / or a protrusion is provided on the outer side of the detection unit on the surface of the substrate.

Description

Encoder

[0001] The present disclosure relates to encoders.

[0002] Encoders are essential for motor control and are used in a wide variety of environments, so they are designed to suit each environment. For example, in encoders used in environments exposed to liquids such as cutting fluid, a substrate on which a detection unit for detecting the rotational speed of a motor is mounted is provided with a coating film to protect the detection unit from the liquid (see, for example, Patent Document 1). However, the coating film is prone to peeling, particularly at the edges of the substrate. If the coating film peels off, cutting fluid can seep into the gap between the coating film and the substrate through the peeled area. If cutting fluid reaches the detection unit, it may cause a decrease in the detection accuracy of the detection unit.

[0003] JP 2010-027843 A

[0004] There is a demand for an encoder that makes it difficult for cutting fluid to reach the detection unit mounted on the board even if the coating peels off at the edge of the board.

[0005] The encoder according to the present disclosure includes a moving body, a detection unit that detects a change in magnetic field or a change in light intensity accompanying the movement of the moving body in order to detect the amount of movement of the moving body, a substrate on whose surface the detection unit is mounted, and a coating film that covers the surface of the substrate together with the detection unit. At least one of a recess and a protrusion is provided on the surface of the substrate outside the detection unit.

[0006] FIG. 1 is a diagram showing an example of the configuration of an encoder according to this embodiment. FIG. 2 is a plan view showing an example of the substrate of FIG. 1. FIG. 3 is a cross-sectional view taken along line A-A' in FIG. 2. FIG. 4 is a plan view showing a first modified example of the substrate of FIG. 1. FIG. 5 is a cross-sectional view taken along line B-B' in FIG. 4. FIG. 6 is a plan view showing a second modified example of the substrate of FIG. 1. FIG. 7 is a cross-sectional view taken along line C-C' in FIG. 6. FIG. 8 is a plan view showing a third modified example of the substrate of FIG. 1. FIG. 9 is a plan view showing a fourth modified example of the substrate of FIG. 1.

[0007] The encoder according to this embodiment will be described with reference to the drawings. In the following description, components having substantially the same functions and configurations are denoted by the same reference numerals, and repeated description will be given only when necessary. In order to distinguish between convex and concave portions in the drawings, convex portions are represented by thick solid lines as shown in Figures 2 and 6, and concave portions are represented by thick dotted lines as shown in Figures 4 and 6.

[0008] 1, the encoder 1 according to this embodiment includes a moving body 11, a detection unit 15 that detects changes in the magnetic field or the amount of light associated with the movement of the moving body 11 in order to detect the amount of movement of the moving body 11, and a substrate 13 on whose surface the detection unit 15 is mounted. If the encoder 1 is a magnetic type that detects changes in the magnetic field associated with the movement of the moving body 11, the detection unit 15 is a magnetoresistive element. If the encoder 1 is an optical type that detects changes in the amount of light associated with the movement of the moving body 11, the detection unit 15 is a light-receiving element. The encoder 1 according to this embodiment will be described as a rotary encoder, but it may also be a linear encoder.

[0009] As shown in Fig. 2, a first protrusion 17a is provided on the surface of the substrate 13 outside the detection unit 15. More preferably, the first protrusion 17a forms a closed rectangular frame that surrounds the entire detection unit 15. Furthermore, a second protrusion 17b having a similar shape to the first protrusion 17a is provided outside the first protrusion 17a. The first protrusion 17a and the second protrusion 17b form a double frame that surrounds the detection unit 15. Of course, three or more protrusions may form a multiple frame, or only the first protrusion 17a may be provided.

[0010] An existing board number and the like are silk-screen printed on the board 13. During this silk-screen printing process, the convex portions 17 (first convex portion 17a, second convex portion 17b) are printed. Of course, the convex portions 17 may be printed in a separate process from the board number and the like. The convex portions 17 may also be printed by a method separate from the board number and the like. As is well known, silk-screen printing methods include inkjet printing, photography, silk-screen printing, and the like, and an appropriate method may be selected.

[0011] 2, the frame lines of the first and second protrusions 17a and 17b surrounding the detection unit 15 are illustrated as a rectangle, but are not limited to a rectangle and may be other shapes such as a circle, an ellipse, a polygon, or a triangle. Furthermore, the first and second protrusions 17a and 17b are illustrated as solid lines, but they may also be dotted, dashed, or chain lines. Furthermore, the first and second protrusions 17a and 17b may be dots or the like distributed two-dimensionally over the entire belt-shaped region surrounding the detection unit 15.

[0012] 3, the encoder 1 has a coating film 19 that covers the surface of the substrate 13 on which the convex portions 17 are provided, together with the detection portion 15. Typically, the coating film 19 is formed by chemical vapor deposition using a CVD (Chemical Vapor Deposition) method. Of course, known film formation methods such as physical vapor deposition methods such as PVD (Physical Vapor Deposition), sputtering, MOD, sol-gel, and spin coating can also be used to form the coating film 19.

[0013] As shown in Figure 3, convex portions 17 are provided on the surface of substrate 13 so as to surround detection unit 15, and convex portions 17 form unevenness together with the surface of substrate 13. The surface area of ​​the uneven portions is increased compared to that of flat portions where convex portions 17 are not provided. This improves the adhesion of coating film 19 to the uneven portions compared to that to flat portions. Therefore, even if coating film 19 peels off from the flat portions at the edge of substrate 13 and cutting fluid seeps between coating film 19 and the surface of substrate 13, the uneven portions can block the intrusion of cutting fluid, reducing the risk of detection unit 15 failing due to exposure to cutting fluid.

[0014] In FIGS. 2 and 3 , the unevenness is formed by providing protrusions 17 on the substrate surface. However, the unevenness may also be formed by providing recesses on the substrate surface. An encoder according to a first modified example will be described below with reference to FIGS. 4 and 5 . As shown in FIG. 4 , in the encoder according to the first modified example, a first recess 27a is provided on the surface of the substrate 23 outside the detection unit 25. More preferably, the first recess 27a forms a rectangular, closed, linear groove frame that surrounds the entire detection unit 25. Furthermore, a second recess 27b having a similar shape to the first recess 27a is provided outside the first recess 27a. The first recess 27a and the second recess 27b form a double frame that surrounds the detection unit 25. Of course, three or more recesses may form a multiple frame. The recess 27 (first and second recesses 27a, 27b) is a cut groove formed by cutting the solder resist on the outermost layer of the substrate 23. Of course, the recess 27 only needs to be recessed relative to the surrounding flat portion, and the process for creating it is not limited to the above. For example, the recess 27 may be formed by cutting during the process of cutting out the substrate 23 from a so-called bare substrate, which is a laminated board made of glass epoxy, paper phenol, or the like, with a thin copper foil attached to the surface, or by etching. The recess 27 may also be formed by laser printing or the like to form a substrate number or the like. Laser printing is a method of printing by irradiating a target object with a laser beam to melt, scorch, peel, oxidize, or scrape the surface of the target object. The recess 27 can be formed in the substrate 23 by applying laser printing.

[0015] 4, the frame lines of the first and second recesses 27a, 27b surrounding the detection unit 25 are illustrated as a rectangle, but are not limited to a rectangle and may be other shapes such as a circle, an ellipse, a polygon, or a triangle. Furthermore, the first and second recesses 27a, 27b are illustrated as solid lines, but may be dotted lines, dashed lines, or chain lines. Furthermore, the first and second recesses 27a, 27b may be dots or the like distributed two-dimensionally over the entire belt-shaped region surrounding the detection unit 25.

[0016] As shown in Figure 5, recess 27 is provided to surround detection unit 25, and recess 27 forms an uneven surface together with the surface of substrate 23. The surface area of ​​the uneven portion is increased compared to that of a flat portion without recess 27. This improves the adhesion of coating film 29 to the uneven portion compared to that of the flat portion. Therefore, even if coating film 29 peels off from the flat portion at the edge of substrate 23 and cutting fluid seeps between coating film 29 and the surface of substrate 23, the uneven portion can prevent the cutting fluid from seeping in. Furthermore, even if cutting fluid does seep in, the seeping cutting fluid can be stored in recess 27, further reducing the risk of detection unit 25 failing due to exposure to cutting fluid.

[0017] Although the configuration in which a protrusion 17 is provided on the outside of the detection unit has been described with reference to FIGS. 2 and 3 , and the configuration in which a recess 27 is provided on the outside of the detection unit has been described with reference to FIGS. 4 and 5 , both a protrusion and a recess may be provided on the outside of the detection unit. Below, an encoder according to a second modification will be described with reference to FIGS. 6 and 7 . As shown in FIG. 6 , in the encoder according to the second modification, a protrusion 37 is provided on the surface of the substrate 33 outside the detection unit 35. More preferably, the protrusion 37 forms a closed rectangular frame that surrounds the entire detection unit 35. Furthermore, a recess 38 having a similar shape to the protrusion 37 is provided outside the protrusion 37. The protrusion 37 and the recess 38 form a double frame that surrounds the detection unit 35. Of course, multiple protrusions 37 and multiple recesses 38 may form a multiple frame.

[0018] 6, the frame lines of the convex portions 37 and concave portions 38 surrounding the detection unit 35 are illustrated as a rectangle, but are not limited to a rectangle and may be other shapes such as a circle, an ellipse, a polygon, or a triangle. Furthermore, the convex portions 37 and the concave portions 38 are illustrated as solid lines, but at least one of them may be a dotted line, a dashed line, or a chain line. Furthermore, at least one of the convex portions 37 and the concave portions 38 may be dots or the like distributed two-dimensionally over the entire belt-shaped region surrounding the detection unit 35.

[0019] As shown in Figure 7, the protrusions 37 and recesses 38 are provided to surround the detection unit 35, so that the protrusions 37 form unevenness together with the surface of the substrate 33, and similarly, the recesses 38 form unevenness together with the surface of the substrate 33. The surface area of ​​the uneven portions is increased compared to that of flat portions without the protrusions 37 or recesses 38. This improves the adhesion of the coating film 39 to the uneven portions compared to that to the flat portions. Therefore, even if the coating film 39 peels off from the flat portions at the edge of the substrate 33 and cutting fluid seeps between the coating film 39 and the surface of the substrate 33, the uneven portions can block the intrusion of cutting fluid, reducing the risk of failure of the detection unit 35 due to exposure to cutting fluid.

[0020] Although the protrusions 17 are illustrated as lines in FIGS. 2 and 3 , the protrusions 17 are not limited to lines. For example, as shown in FIG. 8 , the protrusions may include a graphic such as a barcode as shown in the first region 47a of the entire band-shaped area surrounding the detection unit 45 mounted on the surface of the substrate 43. Alternatively, the protrusions may include text such as the manufacturing location or date of the substrate 43 as shown in the second region 47b. Alternatively, the protrusions may include a symbol as shown in the third region 47c. Alternatively, the protrusions may include text such as a serial number as shown in the fourth region 47d. These text, symbols, and symbols may potentially increase the surface area compared to a frame, thereby improving adhesion to the coating film and more effectively preventing the intrusion of cutting fluid. Of course, the text, symbols, and shapes that can be used as the protrusions are not limited to the above. They may also include manufacturer information, model name, date, identification ID, logo, or a graphic symbol indicating the orientation of the substrate 43, which are commonly printed by silk screen printing. Since the letters, symbols, and figures that originally needed to be printed can be printed only around the detection unit 45, the increase in printing time can be suppressed compared to printing a design only for the protrusions. Furthermore, the figures, letters, and symbols as the protrusions shown in the above-mentioned regions 47a, 47b, 47c, and 47d may be provided as recesses formed by laser printing or the like. Of course, the recesses may be provided by stamping like an engraving, rather than by laser or cutting.

[0021] In Figures 2 and 3, the surface of the substrate 13 is provided with first and second protrusions 17a and 17b that form a rectangular closed frame that surrounds the entire detection unit 15. However, the protrusions 17 do not necessarily have to be provided so as to surround the entire detection unit 15. For example, as shown in Figure 1, if the surface of the substrate 13 is parallel to the vertical direction (Z-axis direction) and the top and bottom of the substrate 13 are fixed (here, the +Z-axis direction is upward and the -Z-axis direction is downward with respect to the detection unit 15), the possibility of cutting fluid reaching the detection unit 15 from the -Z-axis direction against gravity is extremely low. Therefore, it is sufficient to provide for cutting fluid infiltration from three directions: the +Z-axis direction, the +X-axis direction, and the -X-axis direction with respect to the detection unit 15. In such a case, as shown in Figure 9, the first and second protrusions 57a and 57b provided on the surface of the substrate 53 may be U-shaped frame lines that are open in the -Z-axis direction. Of course, if it is necessary to prepare for intrusion into the detection unit 55 only from the +Z axis direction, a convex portion may be provided only above the detection unit 55.

[0022] The following supplementary notes are further disclosed regarding this embodiment and the modified examples. (Supplementary Note 1) The encoder 1 includes a moving object 11, a detection unit 15 that detects a change in magnetic field or a change in light intensity accompanying the movement of the moving object 11 in order to detect the amount of movement of the moving object 11, a substrate 13 on whose surface the detection unit 15 is mounted, and a coating film 19 that covers the surface of the substrate 13 together with the detection unit 15, and at least one of a recess 27 and a protrusion 17 is provided on the surface of the substrate 13 outside the detection unit 15. (Supplementary Note 2) In the encoder 1 described in Supplementary Note 1, at least one of the recess 27 and the protrusion 17 is provided so as to surround the entire detection unit 15. (Supplementary Note 3) In the encoder 1 described in Supplementary Note 1, at least one of the recess 27 and the protrusion 17 is provided as a closed frame that surrounds the detection unit 15. (Supplementary Note 4) In the encoder 1 described in Supplementary Note 3, the frame is a rectangle, a circle, an ellipse, or a polygon. (Supplementary Note 5) In the encoder 1 described in Supplementary Note 3, the frame line is a solid line, a dotted line, a dashed line, or a chain line. (Supplementary Note 6) In the encoder 1 described in Supplementary Note 1, at least one of the recessed portions 27 and the protruding portions 17 are dots distributed two-dimensionally over the entire band-shaped area surrounding the detection unit 15. (Supplementary Note 7) In the encoder 1 described in Supplementary Note 1, at least one of the recessed portions 27 and the protruding portions 17 are provided outside a portion of the detection unit 15. (Supplementary Note 8) In the encoder 1 described in Supplementary Note 1, at least one of the recessed portions 27 and the protruding portions 17 are provided as lines, figures, symbols, or characters. (Supplementary Note 9) In the encoder 1 described in Supplementary Note 1, the recessed portions 27 are cutting grooves in the surface of the substrate 13.

[0023] Although the embodiments of the present disclosure have been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the invention or the concept and spirit of the present invention derived from the content of the claims and their equivalents. For example, in the above-described 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 mathematical expressions are used in the description of the above-described embodiments.

[0024] 1...encoder, 11...moving body, 13...substrate, 15...detecting portion, 17 (17a, 17b)...convex portion

Claims

1. A mobile body, a detection unit that detects a change in magnetic field or a change in light amount accompanying the movement of the mobile body in order to detect the movement amount of the mobile body, a substrate on which the detection unit is mounted on the surface, and a coating film that covers the surface of the substrate together with the detection unit, wherein at least one of a concave portion and a convex portion is provided outside the detection unit on the surface of the substrate. Encoder.

2. The encoder according to claim 1, wherein at least one of the concave portion and the convex portion is provided so as to surround the entire detection unit.

3. The encoder according to claim 2, wherein at least one of the concave portion and the convex portion is provided as a closed frame line surrounding the detection unit.

4. The encoder according to claim 3, wherein the frame line is in the shape of a quadrilateral, a circle, an ellipse or a polygon.

5. The encoder according to claim 3, wherein the frame line is a solid line, a dotted line, a broken line or a chain line.

6. The encoder according to claim 1, wherein at least one of the concave portion and the convex portion is dots two-dimensionally distributed over the entire strip-shaped region surrounding the detection unit.

7. The encoder according to claim 1, wherein at least one of the concave portion and the convex portion is provided outside a part of the detection unit.

8. The encoder according to claim 1, wherein at least one of the concave portion and the convex portion is provided as a line, a figure, a symbol or a character.

9. The encoder according to claim 1, wherein the concave portion is a cutting groove on the surface of the substrate.

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