Linear encoder and linear conveyance system

Abstract

To provide a linear encoder and linear conveyance system that can accurately manage a gap dimension between a position detection sensor and a linear scale.SOLUTION: A linear encoder 60 comprises: a sensor substrate 65; position detection sensors 64 provided on one surface 65A of the sensor substrate 65; a positioning plate 62 having window portions 62b provided on portions facing the position detection sensors 64; and fixing portions 80 that fix the sensor substrate 65 to a positioning plate 62. The plurality of position detection sensors 64 is arranged in the window portions 62b in a state where one surface 65A of the sensor substrate 65 is in contact with the positioning plate 62.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a linear encoder and a linear transport system. [Background technology]

[0002] Patent Document 1 listed below discloses an electronic scale using an inductive position transducer element. This electronic scale includes a first member, an elongated beam member having a measurement axis along which the first member is movable, at least one magnetic field generator that generates a fluctuating magnetic flux in a magnetic flux field in response to a drive signal, at least one magnetic flux modulator that can be arranged in the magnetic flux field and can change the fluctuating magnetic flux in a modulation field nearby, and at least one magnetic flux sensor that is arranged in the magnetic flux field, detects the fluctuating magnetic flux in the magnetic flux field, and generates an output signal indicative of a relative position between it and the at least one magnetic flux modulator based on the detected magnetic flux, and each of the magnetic field generators and each of the magnetic flux sensors forms a continuous spatially modulated inductive coupling. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-325002 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to perform highly accurate measurements in the linear encoder described above, it is necessary to precisely control the gap dimension between the position detection sensor and the linear scale.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a linear encoder and a linear transport system that can accurately manage the gap dimension between a position detection sensor and a linear scale. [Means for solving the problem]

[0006] In order to solve the above problems, a linear encoder according to one embodiment of the present invention comprises a sensor substrate, a plurality of position detection sensors provided on one surface of the sensor substrate, a positioning plate having a plurality of window portions provided in a portion facing the plurality of position detection sensors, and a fixing portion for fixing the sensor substrate to the positioning plate, wherein the plurality of position detection sensors are positioned within the plurality of window portions with the one surface of the sensor substrate abutting the positioning plate.

[0007] Moreover, a linear conveying system according to one embodiment of the present invention comprises a movable body having a linear scale, a track body that guides the movable body, and a conveying unit that is arranged along the track body and has a linear encoder that can face the linear scale, wherein a plurality of the conveying units can be connected so that the track bodies are continuous, and the linear encoder is the linear encoder described above. Effect of the Invention

[0008] According to one aspect of the present invention, the gap dimension between the position detection sensor and the linear scale can be managed with high precision. [Brief description of the drawings]

[0009] [Figure 1] 1 is an overall view of a linear transport system according to an embodiment; [Diagram 2] FIG. 2 is a perspective view of a moving body and a transport unit according to an embodiment. [Diagram 3] FIG. 2 is a diagram showing a movable body and a transport unit according to an embodiment as viewed from the X-axis direction. [Figure 4] FIG. 4 is a diagram showing a transport unit according to an embodiment as viewed from the Y-axis direction. [Diagram 5] FIG. 2 is a rear perspective view of a linear encoder according to an embodiment; [Figure 6] FIG. 2 is a rear perspective view of the mounting base and positioning plate according to the embodiment; [Figure 7]7 is a cross-sectional view taken along line VII-VII of FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] FIG. 1 is an overall view of a linear transport system 1 according to an embodiment. 1, the linear conveyance system 1 includes a moving body 2 and a conveyance unit 3. The conveyance unit 3 includes a track body 30 that guides the moving body 2, and a linear encoder 60 arranged along the track body 30.

[0012] A plurality of transport units 3 can be connected so that the track members 30 are continuous. In the example of Fig. 1, three transport units 3 are connected. A connecting rail 31 is provided between the track members 30 of each transport unit 3. The movable body 2 can move along the track members 30 connected together by the connecting rail 31.

[0013] In the following description, an XYZ orthogonal coordinate system is set, and the positional relationship of each member may be described with reference to this XYZ orthogonal coordinate system. The X-axis direction is the length direction of the track body 30 (the direction of movement of the moving body 2). The Y-axis direction is the width direction of the track body 30, which is perpendicular to the X-axis direction. The Z-axis direction is the height direction of the track body 30, which is perpendicular to the X-axis and Y-axis directions.

[0014] Fig. 2 is a perspective view of the movable body 2 and the transport unit 3 according to one embodiment. Fig. 3 is a view of the movable body 2 and the transport unit 3 according to one embodiment as viewed from the X-axis direction. As shown in FIG. 3, the moving body 2 includes a table 10, a slider block 11, a magnet 12, and a linear scale 13.

[0015] The table 10 includes a top plate portion extending along the XY plane and a pair of side walls extending downward from both ends of the top plate portion in the Y-axis direction. An object to be conveyed (not shown) can be fixed to the upper surface side of the top plate portion of the table 10.

[0016] A slider block 11 is attached to the underside of the top plate of the table 10. The slider block 11 is engaged with the track body 30 so as to be movable in the X-axis direction. Recesses are formed on both side surfaces of the track body 30 in the Y-axis direction, and the slider block 11 has protrusions that engage with the recesses.

[0017] A rolling element transfer path for endlessly transferring the rolling elements (not shown) may be formed between the recess of the track body 30 and the protrusion of the slider block 11. The rolling element transfer path may be provided, for example, in two rows, one on each side in the Y-axis direction, or in four rows, two on each side in the Y-axis direction.

[0018] In addition, a magnet 12 is attached to the underside of the top plate of the table 10. The magnet 12 is disposed on the -Y side of the slider block 11. The magnetic poles of the magnet 12 face downward. The downward magnetic poles of the magnet 12 are arranged such that the N poles and S poles are alternately arranged in the X-axis direction.

[0019] A linear scale 13 is attached to the inner wall surface of the side wall on the +Y side of the table 10. The linear scale 13 is formed in the shape of a thin bar extending in the X-axis direction. The linear scale 13 faces a detection unit 64a of the linear encoder 60 in the Y-axis direction. The linear scale 13 and the linear encoder 60 may be of either an optical type or a magnetic type.

[0020] The transport unit 3 includes a base member 20, a track body 30, a coil unit 40, a drive substrate 50, a linear encoder 60, and a cover 70. The base member 20 includes a bottom plate portion 21, a first column portion 22, and a second column portion 23. The bottom plate portion 21 is formed in a plate shape extending along the XY plane.

[0021] The first pillar portion 22 stands upward (to the +Z side) from the center in the Y-axis direction of the bottom plate portion 21. The above-mentioned track body 30 is attached to the top of the first pillar portion 22. As shown in Fig. 2, the first pillar portion 22 extends in the X-axis direction together with the track body 30. A first mounting portion 22a (step) is formed on the surface of the first pillar portion 22 facing the -Y side.

[0022] The second pillar portion 23 is disposed on the -Y side of the first pillar portion 22, and stands upward (to the +Z side) from the bottom plate portion 21. The second pillar portion 23 also extends in the X-axis direction together with the first pillar portion 22 (first mounting portion 22a). The height of the top of the second pillar portion 23 is the same as the height of the first mounting portion 22a. A support member 41 is installed between the second pillar portion 23 and the first mounting portion 22a.

[0023] 3, the support member 41 is formed in an L-shape when viewed from the X-axis direction. The support member 41 supports the coil unit 40. The coil unit 40 faces the magnet 12 in the Z-axis direction. The coil unit 40 includes U-phase, V-phase, and W-phase coil groups arranged along the X-axis direction. For example, a plurality of the coil units 40 (four in this embodiment) are arranged side by side in the X-axis direction.

[0024] 3, the drive board 50 is disposed below (-Z side) the coil unit 40 and fixed onto the bottom plate portion 21. The drive board 50 is connected to the coil unit 40 via a cable (not shown), and controls the movement of the moving body 2 in the X-axis direction by passing a current through the coil unit 40. The drive board 50 is disposed penetrating the first pillar portion 22 in the Y-axis direction.

[0025] The cover 70 covers a portion of the drive board 50 that protrudes from the first pillar portion 22 to the +Y side. The cover 70 is provided with various connectors that connect the drive board 50 to an external device (not shown). For example, reference numerals 71 and 72 in FIG. 2 are communication connectors. Reference numeral 73 is a power connector. Reference numeral 74 is a USB connector.

[0026] A second mounting portion 22b (step) is formed on the surface facing the +Y side of the first column portion 22. A linear encoder 60 is attached to the second mounting portion 22b. As shown in FIG. 3, the linear encoder 60 is formed in an L-shape when viewed from the X-axis direction. The linear encoder 60 includes a mounting base 61, a positioning plate 62, a sensor cover 63, and a position detection sensor 64.

[0027] The mounting base 61 is formed in a plate shape extending along the XY plane, and is fixed to the second mounting portion 22b. A positioning plate 62 is attached to the +Y side end of the mounting base 61 by a screw member 61a. The positioning plate 62 stands upward (on the +Z side) from the +Y side end of the mounting base 61. The positioning plate 62 extends along the XZ plane.

[0028] 2, the positioning plate 62 extends along the movement direction (X-axis direction) of the movable body 2 and faces the linear scale 13 in the Y-axis direction. A protective film 62a is attached to the surface of the positioning plate 62 facing the linear scale 13. The non-facing surface side of the positioning plate 62 is covered by a sensor cover 63, as shown in FIG. 3. A sensor board 65, which will be described later, is arranged inside the sensor cover 63.

[0029] Fig. 4 is a view of the transport unit 3 according to one embodiment as viewed from the Y-axis direction. Fig. 5 is a rear perspective view of the linear encoder 60 according to one embodiment. Fig. 6 is a rear perspective view of the mounting base 61 and the positioning plate 62 according to one embodiment. Fig. 7 is a cross-sectional view taken along the line VII-VII shown in Fig. 4. In these figures, the protective film 62a of the positioning plate 62 is not shown in order to improve visibility.

[0030] 5 and 7, the linear encoder 60 includes a sensor substrate 65. A position detection sensor 64 is provided on one surface 65A of the sensor substrate 65 facing the +Y side (the linear scale 13 side). A plurality of position detection sensors 64 (four in this embodiment) are provided on the sensor substrate 65 at intervals in the X-axis direction, as shown in FIG.

[0031] 4 and 6, the positioning plate 62 has a plurality of windows 62b in a portion facing the plurality of position detection sensors 64. That is, the positioning plate 62 is provided with a plurality of (four in this embodiment) windows 62b spaced apart in the X-axis direction. Note that, although the window portions 62b in this embodiment are rectangular openings formed in the positioning plate 62, the shape is not limited to a rectangular shape as long as the shape corresponds to the position detection sensors 64.

[0032] The sensor substrate 65 is fixed to the positioning plate 62 by fixing portions 80, which will be described later. As shown in Fig. 4, the fixing portions 80 are provided on both sides in the X-axis direction of each of the multiple position detection sensors 64. The elements of the position detection sensors 64 (including the detection portions 64a) are disposed in the window portions 62b with one surface 65A of the sensor substrate 65 in contact with the positioning plate 62, as shown in Fig. 7.

[0033] 5, a first fixing hole 61b, a second fixing hole 61c, and an elongated hole 61d are formed in the mounting base 61. A screw member (not shown) for attaching the mounting base 61 to the second mounting portion 22b (see FIGS. 2 and 3) is disposed in the first fixing hole 61b. A plurality of first fixing holes 61b are formed at intervals in the X-axis direction along the edge of the mounting base 61 on the -Y side.

[0034] The second fixing hole 61c is formed on the mounting base 61 on the +Y side of the first fixing hole 61b. A screw member 92 that fixes the sensor cover 63 in the Z-axis direction from below is disposed in the second fixing hole 61c. The sensor cover 63 is also fixed in the Y-axis direction to a plurality of fixed cylinders 91 fixed to the positioning plate 62 by a screw member (not shown).

[0035] 5, the long hole 61d is formed along the edge of the mounting base 61 on the +Y side. A connection wire (not shown) that can be connected to a connector 65a provided on the other surface 65B of the sensor board 65 is arranged in the long hole 61d. The connection wire electrically connects the sensor board 65 and the drive board 50. The other surface 65B of the sensor board 65 is the surface facing the -Y side and is the surface opposite to the one surface 65A facing the +Y side (linear scale 13 side).

[0036] A positioning protrusion 61e for positioning the sensor board 65 in the X-axis direction is formed on the +Y side of the long hole 61d in the mounting base 61. The positioning protrusion 61e stands upward (+Z side) from the +Y side edge of the mounting base 61. A positioning recess 65b for engaging with the positioning protrusion 61e is formed on the lower edge of the sensor board 65. The positioning recess 65b is recessed upward (+Z side).

[0037] 7, the fixing part 80 includes a support member 81 provided on the positioning plate 62, a collar member 82 movable in the Y-axis direction along the support member 81, and a fastening member 83 that fastens and fixes the collar member 82 to the support member 81. The support member 81 is positioned in a different position from the fixed cylinder 91 (see FIG. 6) described above, but has the same configuration.

[0038] The support member 81 is formed in a cylindrical shape extending from the positioning plate 62 to the -Y side. A female screw is formed on the inner peripheral surface of the support member 81. The support member 81 is made of metal, and is fixed to the positioning plate 62 by caulking, as shown in Fig. 7. A deformed portion 81a having a larger diameter than the outer peripheral surface of the support member 81 is formed on the end of the support member 81 on the +Y side.

[0039] Before being crimped to the positioning plate 62, the deformed portion 81a has an expanded portion that is larger than the fixing hole 62c formed in the positioning plate 62. By positioning this deformed portion 81a in the fixing hole 62c and pushing the expanded portion into the fixing hole 62c with a press or the like, the expanded portion is deformed and the support member 81 can be fixed to the positioning plate 62.

[0040] The collar member 82 is made of resin, and is formed into a cylindrical shape that is slidable in the Y-axis direction along the outer circumferential surface of the support member 81. An annular flange portion 82a having a larger diameter than the outer circumferential surface of the collar member 82 is formed on the end portion on the +Y side of the collar member 82. The flange portion 82a abuts against the other surface 65B of the sensor board 65, and fixes (clamps) the sensor board 65 between itself and the positioning plate 62.

[0041] The fastening member 83 includes a screw member 83a and a washer member 83b. The screw member 83a is screwed into the support member 81 from the -Y side. The washer member 83b is interposed between the opening edge on the -Y side of the collar member 82 and the head of the screw member 83a. Note that if the outer diameter of the head of the screw member 83a is larger than the inner diameter of the collar member 82, it is not necessarily necessary to provide the washer member 83b.

[0042] The sensor board 65 has a through hole 65c that penetrates from one surface 65A to the other surface 65B and into which the support member 81 is inserted. The outer diameter of the flange portion 82a of the collar member 82 is larger than the inner diameter of the through hole 65c. When the fastening member 83 (screw member 83a) is tightened, the collar member 82 abuts against the other surface 65B of the sensor board 65, and the sensor board 65 is fixed in a state where one surface 65A of the sensor board 65 abuts against the positioning plate 62.

[0043] 7, the only factor causing an error in the dimension of the gap G1 between the position detection sensor 64 and the linear scale 13 is the height H1 of the element of the position detection sensor 64. In other words, since the thickness of the sensor substrate 65 and the like are no longer a factor causing an error in the dimension of the gap G1, the dimension of the gap G1 between the position detection sensor 64 and the linear scale 13 can be managed with high precision.

[0044] As described above, the linear encoder 60 of this embodiment includes a sensor substrate 65, a plurality of position detection sensors 64 provided on one surface 65A of the sensor substrate 65, a positioning plate 62 having a plurality of windows 62b provided in a portion facing the plurality of position detection sensors 64, and a fixing portion 80 for fixing the sensor substrate 65 to the positioning plate 62, and the plurality of position detection sensors 64 are disposed within the plurality of windows 62b with the one surface 65A of the sensor substrate 65 in contact with the positioning plate 62. With this configuration, the dimension of the gap G1 between the position detection sensors 64 and the linear scale 13 can be controlled with high precision.

[0045] Moreover, in this embodiment, the fixing portion 80 is provided on both sides of each of the multiple position detection sensors 64. According to this configuration, one surface 65A of the sensor substrate 65 is in contact with the positioning plate 62 at least on both sides of the position detection sensor 64, so that the dimension of the gap G1 between the position detection sensor 64 and the linear scale 13 can be controlled with higher accuracy.

[0046] In this embodiment, the fixing portion 80 includes a support member 81 provided on the positioning plate 62, a collar member 82 movable along the support member 81, and a fastening member 83 fastening the collar member 82 to the support member 81, and the sensor board 65 is formed with a through hole 65c penetrating from one surface 65A to the other surface 65B and into which the support member 81 is inserted, and the collar member 82 abuts against the other surface 65B of the sensor board 65 in a state where it is fastened to the support member 81. With this configuration, the one surface 65A of the sensor board 65 can be closely attached to the positioning plate 62 without the fixing portion 80 protruding toward the linear scale 13 side (+Y side). This makes it possible to reduce the gap G1.

[0047] Furthermore, in this embodiment, the support members 81 are fixed to the positioning plate 62 by crimping. With this configuration, compared to a case where the support members 81 are welded to the positioning plate 62, distortion is less likely to occur in the positioning plate 62, and the dimension of the gap G1 between the position detection sensor 64 and the linear scale 13 can be controlled with greater precision. Note that the positioning plate 62 and the support members 81 may be formed by, for example, machining, although this requires more processing costs than crimping.

[0048] Moreover, the linear conveyance system 1 of this embodiment includes a movable body 2 equipped with a linear scale 13, a track body 30 that guides the movable body 2, and a conveyance unit 3 that is arranged along the track body 30 and equipped with a linear encoder 60 that can face the linear scale 13, and a plurality of conveyance units 3 can be connected so that the track body 30 is continuous. According to this configuration, since the dimension of the gap G1 between the position detection sensor 64 and the linear scale 13 in each conveyance unit 3 can be precisely controlled, even if a plurality of conveyance units 3 are connected, the position detection accuracy of the movable body 2 in the linear conveyance system 1 as a whole can be improved.

[0049] Although the preferred embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to the above embodiment. The shapes and combinations of the components shown in the above embodiment are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention. [Explanation of symbols]

[0050] 1...Linear conveying system, 2...Moving body, 3...Conveying unit, 13...Linear scale, 30...Railway body, 60...Linear encoder, 62...Positioning plate, 62b...Window portion, 64...Position detection sensor, 64a...Detection portion, 65...Sensor board, 65A...One surface, 65B...Other surface, 80...Fixed portion, 81...Support member, 82...Collar member, 83...Fastening member, H1...Element height, G1...Gap

Claims

1. A sensor substrate; A plurality of position detection sensors provided on one surface of the sensor substrate; a positioning plate having a plurality of windows in a portion facing the plurality of position detection sensors; a fixing portion that fixes the sensor substrate to the positioning plate, the plurality of position detection sensors are disposed in the plurality of windows with the one surface of the sensor substrate in contact with the positioning plate; Linear encoder.

2. The fixing portion is provided on both sides of each of the plurality of position detection sensors.

2. The linear encoder according to claim 1.

3. The fixing portion is A support member provided on the positioning plate; a collar member movable along the support member; a fastening member for fastening the collar member to the support member, a through hole is formed in the sensor substrate, the through hole penetrating from the one surface to the other surface and into which the support member is inserted; the collar member is fastened to the support member and abuts against the other surface of the sensor board; 3. The linear encoder according to claim 1 or 2.

4. The support member is fixed to the positioning plate by caulking.

4. The linear encoder according to claim 3.

5. A moving body having a linear scale; a track body that guides the moving body; and a conveying unit that is disposed along the track body and includes a linear encoder that can face the linear scale, The transport unit may be connected to the track body in a continuous manner. The linear encoder according to claim 1 or 2 is provided as the linear encoder. Linear transport system.

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