JP2017075884A - Linear motion and rotation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a linear motion and rotation detector capable of suppressing increase in a linear motion direction, and easily detecting an origin position.SOLUTION: A linear motion/rotation detector 7 includes: a cylindrical magnetic scale 8 linearly moving and rotating; a first magnetic detection element 41 for detection of linear motion position; a second magnetic detection element 42 for detection of rotation position; and an optical sensor 10. The magnetic scale 8 includes a lattice-like magnetization pattern 37 on a peripheral surface of which S poles and N poles are alternately arrayed in an axial direction X and the S poles and the N poles are alternately magnetized around an axial line L. The first magnetic detection element 41 and the second magnetic detection element 42 are arranged oppositely to the magnetization pattern 37. On a surface of the magnetization pattern 37, a reflection pattern 38 configured to detect an origin position is provided. A linear motion position and a rotation position can be detected by the first magnetic detection element 41 and the second magnetic detection element 42 opposite to the same magnetization pattern 37. The origin position can be detected by detecting reflection light from the reflection pattern 38 with the optical sensor 10.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a linear motion rotation detector that detects a rotational position and a linear motion position of a driven object.

  Japanese Patent Application Laid-Open No. 2004-133867 discloses a linear motion rotation drive device that includes a motor unit that linearly moves and rotates an output shaft, and a linear motion rotation detector that detects a linear motion position and a rotational position of the output shaft. In this document, a linear motion rotation detector includes a cylindrical linear motion scale having linear motion graduations provided at regular intervals in the linear motion direction, and a disk-shaped permanent magnet (rotation) magnetized in two poles in the circumferential direction. Scale). The linear motion scale and the permanent magnet are fixed at positions separated in the axial direction of the output shaft. The linear motion rotation detector includes a linear motion displacement detector that reads a linear motion scale and detects displacement in the linear motion direction, and two rotational displacement detectors that detect displacement in the rotational direction from the magnetic field of the permanent magnet. . The two rotational displacement detectors face the permanent magnet at an angular position that is 90 ° apart. The linear motion rotation detector obtains the origin position around the axis by calculating the outputs from the two rotational displacement detectors.

JP 2010-60478 A

  Here, as in Patent Document 1, if outputs from a plurality of detection units have to be calculated in order to detect an origin position, acquisition of the origin position becomes complicated.

  In view of the above problems, an object of the present invention is to provide a linear motion rotation detector that can easily detect an origin position around an axis or in the axial direction.

  In order to solve the above problems, a linear motion rotation detector according to the present invention includes a cylindrical magnetic scale that linearly moves in the axial direction and rotates around the axis, a first magnetic detection element for detecting the linear motion position, A second magnetic detection element for detecting a rotational position; a reflection pattern for detecting an origin position of at least one of the axial direction and about the axis; and a detection unit for detecting reflected light of inspection light from the reflection pattern An optical sensor, and the magnetic scale has S poles and N poles alternately arranged in the axial direction on a circumferential surface around the axis, and S poles and N poles around the axis. Are arranged in a grid pattern, the first magnetic detection element and the second magnetic detection element are arranged to face the magnetization pattern, and the reflection pattern is the magnetic scale. The magnetized pattern in Characterized in that provided overlapping the down position.

  According to the present invention, the origin position is optically detected using the reflection pattern provided on the magnetic scale. That is, the reflected light of the inspection light from the reflection pattern provided on the magnetic scale is detected by the optical sensor to acquire the origin position. Therefore, it is not necessary to calculate outputs from a plurality of detectors in order to detect the origin position, and the origin position can be easily detected.

  In the present invention, in order to provide the reflective pattern at a position overlapping the magnetized pattern on the magnetic scale, the reflective pattern has a sheet-like member provided with the reflective pattern, and the sheet-like member has a surface of the magnetized pattern on the magnetic scale. It can be affixed to.

  In this case, the reflection pattern is for detecting the position of the origin around the axis, and the surface of the magnetized pattern may extend with a certain width in the axis direction. With such a reflection pattern, even when the magnetic scale moves in the axial direction, the origin position around the axial line can be detected by the optical sensor.

  Further, the reflection pattern is for detecting the origin position in the axial direction, and can extend on the surface of the magnetized pattern with a constant width around the axis. With such a reflection pattern, the origin position in the axial direction can be detected by the optical sensor even when the magnetic scale rotates around the axial line.

  In this case, in order to detect both the origin position on one side and the origin position on the other side in the linear movement direction (axial direction) in which the magnetic scale moves linearly, the first direction in the axial direction is used as the reflection pattern. A first direction side reflection pattern for detecting the first origin position, and a second direction side reflection pattern for detecting a second origin position in a second direction opposite to the first direction, The optical sensor includes a first optical sensor that detects the reflected light from the first direction side reflection pattern, and a second optical sensor that detects the reflected light from the second direction side reflection pattern. It can be.

  In the present invention, in order to detect both the origin position in the axial direction and the origin position around the axis, the reflection pattern includes a first reflection pattern portion for detecting the origin position around the axis, and the axial direction. A second reflection pattern portion for detecting the origin position of the first reflection pattern, wherein the first reflection pattern extends on the surface of the magnetization pattern with a certain width in the axial direction, and the second reflection pattern The surface of the magnetic pattern can be extended with a constant width around the axis.

  In this invention, it has a sensor board | substrate provided with the said 1st magnetic detection element and the said 2nd magnetic detection element, and the said 1st magnetic detection element is a magnetoresistive element, and the said magnetic scale is 90 degree phase difference mutually The first magnetic resistance pattern of A phase and the first magnetoresistive pattern of B phase for detecting linear motion of the magnetic field, and the second magnetic detection element is a magnetoresistive element, and the magnetic scale has a phase difference of 90 ° with respect to each other. A second magnetoresistive pattern of A phase and a second magnetoresistive pattern of B phase that detect rotation of the first phase, and the first magnetoresistive pattern of A phase and the first magnetoresistive pattern of B phase are on the sensor substrate. It is preferable that the A-phase second magnetoresistive pattern and the B-phase second magnetoresistive pattern are laminated on the sensor substrate.

  If it does in this way, compared with the case where a 1st magnetic detection element and a 2nd magnetic detection element are each provided in another sensor board, it can control that a direct-acting rotation detector enlarges. In this way, the first magnetic detection element and the second magnetic detection element can be made small on the sensor substrate. Therefore, the sensor substrate can be made small, and the apparatus can be miniaturized.

  In the present invention, the center of the first magnetic detection element and the center of the second magnetic detection element in the width direction on the sensor substrate corresponding to the axis of the magnetic scale are on the sensor substrate. The detection unit of the optical sensor overlaps the virtual plane including the axis passing through the center in the width direction of the first magnetic detection element and the second magnetic detection element, and the first magnetic field in the width direction. It is desirable that the center of the detection element, the center of the second magnetic detection element in the width direction, and the detection unit face the apex of the curvature of the magnetic scale. If it does in this way, it will become easy to obtain a sine wave with few distortions about the output from the 1st magnetic sensing element and the output from the 2nd magnetic sensing element. In addition, it becomes easy to obtain an accurate origin position based on the output from the optical sensor.

In this invention, the said detection part shall be spaced apart from the surface of the said magnetic scale rather than the said 1st magnetic detection element and the said 2nd magnetic detection element. If it does in this way, arrangement | positioning of a sensor board | substrate provided with a 1st magnetic detection element and a said 2nd magnetic detection element, and an optical sensor will become easy.

  According to the linear motion rotation detector of the present invention, the origin position is optically detected using the reflection pattern provided on the magnetic scale. Therefore, the origin position can be easily detected.

It is an external appearance perspective view of the linear motion rotation drive apparatus provided with the linear motion rotation detector of this invention. It is sectional drawing which cut | disconnected the linear motion rotational drive apparatus of FIG. 1 by the surface containing an axis line. It is a disassembled perspective view of the linear motion rotation drive device of FIG. It is explanatory drawing of a linear motion rotation detector. It is explanatory drawing of the magnetic sensor of a linear motion rotation detector. It is explanatory drawing of the circuit which the magnetoresistive element of a magnetic sensor comprises. It is explanatory drawing of the positional relationship of an optical sensor and a magnetic sensor. It is explanatory drawing of the linear motion rotation detector of the modification 1. It is explanatory drawing of the linear motion rotation detector of the modification 2.

  Embodiments of the present invention will be described with reference to the drawings.

(Linear rotation drive device)
FIG. 1 is an external perspective view of a linear motion rotation drive device equipped with a linear motion rotation detector of the present invention. FIG. 2 is a cross-sectional view of the linear motion rotary drive device of FIG. 1 cut along a plane including an axis. FIG. 3 is an exploded perspective view of the linear motion rotary drive device of FIG. As shown in FIG. 1, a direct-acting rotary drive device 1 includes an output shaft 2, a linear motor unit 3 that moves the output shaft 2 along the axis L, and a rotary motor unit that rotates the output shaft 2 around the axis θ. 4 and a ball spline bearing 5. The ball spline bearing 5 supports the output shaft 2 so as to be movable in the axial direction X and transmits the driving force of the rotary motor unit 4 to the output shaft 2.

  Further, the linear motion rotation drive device 1 includes a linear motion rotation detector 7 for detecting the linear motion position and the rotational position of the output shaft 2. The linear rotation detector 7 includes a cylindrical magnetic scale 8 that is coaxially fixed to the output shaft 2, and a magnetic sensor 9 and an optical sensor 10 that face the magnetic scale 8 from a direction orthogonal to the axis L. 1 to 3, the circuit board on which the optical sensor 10 is mounted is omitted.

  The magnetic scale 8, the linear motor unit 3, the rotary motor unit 4, and the ball spline bearing 5 of the linear motion rotation detector 7 are arranged coaxially in this order from one side of the axial direction X to the other side. Yes. In the following description, the axial direction is X, and the axis is θ.

(Linear motor part)
As shown in FIG. 2, the linear motor unit 3 includes a mover 11 and a stator 12. The mover 11 includes an output shaft 2 and a plurality of permanent magnets 13 fixed to the outer peripheral surface of the output shaft 2. Each permanent magnet 13 has an annular shape, and an N pole and an S pole are magnetized in the axial direction X. The plurality of permanent magnets 13 face each other with the adjacent permanent magnets 13 facing the same pole. In this example, ten permanent magnets 13 are fixed to the output shaft 2.

The stator 12 is located on the outer peripheral side of the mover 11. As shown in FIGS. 1 and 2, the stator 12 includes a cylindrical coil array 15 having a plurality of coils 17 arranged coaxially, and a coil array 15.
The wiring board 16 is fixed to the board.

  As shown in FIGS. 2 and 3, the coil array 15 includes a plurality of cylindrical coil units 19 in which three coils 17 adjacent in the axial direction X are integrally covered with a resin 18 and hardened. Each coil unit 19 is coaxially connected in the axial direction X, thereby forming a coil array 15. In this example, the coil array 15 includes seven coil units 19. Therefore, the coil array 15 includes 21 coils 17.

  When each coil unit 19 is viewed from the axial direction X, the contour shape is a rectangle. Each coil unit 19 has a flat shape in which the height dimension in the axial direction X is shorter than the length of each side of the rectangle constituting the contour shape. The length dimension in the axial direction X of each coil unit 19 is about twice the length dimension in the axial direction X of each permanent magnet 13 fixed to the mover 11.

  Each coil unit 19 includes four side surfaces around the axis θ. As shown in FIG. 1, one of the four side surfaces is a substrate fixing surface 19a. As shown in FIG. 3, the start end 17 a and the end end 17 b of each coil 17 in the coil unit 19 are exposed (protruded) from the substrate fixing surface 19 a. Each coil unit 19 is connected in a posture in which the substrate fixing surface 19a is directed in the same direction. The wiring substrate 16 is fixed to a flat surface (substrate fixing surface of the coil array 15) formed by arranging the substrate fixing surfaces 19 a of the coil units 19 in the axial direction X. The wiring board 16 is connected to the start end 17 a and the end end 17 b of each coil 17 of each coil unit 19.

  Here, the linear motor unit 3 is a three-phase motor, and when the linear motor unit 3 is driven, the three coils 17 of each coil unit 19 are respectively a U-phase coil 17 (U) and a V-phase coil 17. (V) functions as a W-phase coil 17 (W). The linear motor unit 3 moves the mover 11 in the axial direction X while moving the coil 17 to be fed in the axial direction X.

(Rotary motor part)
The rotary motor unit 4 includes a mover 21 and a stator 22. The mover 21 includes a hollow nut shaft 23 through which the output shaft 2 passes. As shown in FIG. 3, the nut shaft 23 includes a small-diameter cylindrical portion 23a and a large-diameter cylindrical portion 23b having a larger diameter than the small-diameter cylindrical portion 23a. The large diameter cylindrical portion 23b is continuously provided on the ball spline bearing 5 side of the small diameter cylindrical portion 23a. The mover 21 includes a cylindrical yoke 24 fixed to the outer peripheral surface of the small-diameter cylindrical portion 23 a of the nut shaft 23, and a cylindrical permanent magnet 25 fixed to the outer peripheral surface of the yoke 24. The permanent magnet 25 has a cylindrical shape, and a plurality of N and S poles are alternately magnetized around the axis θ (circumferential direction).

  The stator 22 is located on the outer peripheral side of the permanent magnet 25. The stator 22 includes a cylindrical yoke 26 surrounding the permanent magnet 25 from the outer peripheral side, and a plurality of coils 27 fixed to the inner peripheral surface of the yoke 26. Each coil 27 is fixed to the yoke 26 in such a posture that its hollow portion is oriented in the radial direction orthogonal to the axis L. The plurality of coils 27 are arranged around the axis line θ. In this example, the stator 22 includes six coils 27. The yoke 26 is held by the case 28 from the outer peripheral side. The contour shape when the case 28 is viewed from the axial direction X is a square.

By supplying power to the coil 27, the nut shaft 23 rotates about the axis around θ. Here, a ball nut 31 constituting the ball spline bearing 5 is disposed on the inner peripheral side of the large-diameter cylindrical portion 23 b of the nut shaft 23. In FIG. 2, the balls constituting the ball spline bearing 5 and the splines provided on the output shaft 2 are omitted. The rotation of the nut shaft 23 is transmitted to the output shaft 2 via the ball nut 31. Therefore, when the rotary motor unit 4 is driven, the output shaft 2 rotates. The large diameter cylindrical portion 23 b of the nut shaft 23 is covered with a bearing case 32. The contour shape when the bearing case 32 is viewed from the axial direction X is a square. If the rotary motor unit 4 according to this embodiment is used, only the output shaft 2 can move in the axial direction X without the mover 21 moving in the axial direction X, so that the rotary motor unit 4 can be downsized. It is.

(Linear rotation detector)
FIG. 4 is an explanatory diagram of the linear motion rotation detector 7. As shown in FIG. 4, the magnetic scale 8 is cylindrical. As shown in FIGS. 1 to 3, the magnetic scale 8 is coaxially fixed to the output shaft 2 in a state where the output shaft 2 passes through the center hole. The magnetic scale 8 moves linearly in the axial direction X integrally with the output shaft 2 and rotates about the axis θ. In FIG. 4, the circuit board on which the optical sensor 10 is mounted is omitted.

  The magnetic scale 8 includes a cylindrical member 35 serving as a fixing portion to the output shaft 2 and an annular permanent magnet 36 fixed to the outer peripheral side of the cylindrical member 35. The permanent magnet 36 is a lattice in which S poles and N poles are alternately arranged in the axial direction X on the circumferential surface around the axis θ, and S poles and N poles are alternately magnetized around the axis θ. A magnetized pattern 37 is provided. Here, the lattice-like magnetized pattern 37 is provided with a plurality of axial tracks 37a extending in the axial direction X in parallel in the axial direction θ, with S poles and N poles alternately arranged in the axial direction X. The lattice-like magnetized pattern 37 includes a plurality of circumferential tracks 37b arranged in parallel in the axial direction X, with S and N poles alternately arranged around the axial line θ and extending around the axial line θ.

  Here, in the magnetic scale 8, a reflective pattern 38 is provided at a position overlapping the magnetized pattern 37. The reflection pattern 38 is the surface of the sheet-like member 39 attached to the surface of the magnetized pattern 37 in the magnetic scale 8. The sheet-like member 39 has silver deposited on the surface, and the reflectance of the surface is 95% or more. The back surface of the sheet-like member 39 is an adhesive surface coated with an adhesive material. The sheet-like member 39 (reflection pattern 38) extends with a constant width in the axial direction X. The length dimension of the sheet-like member 39 (reflection pattern 38) in the axial direction X is equal to or greater than the linear movement distance of the output shaft 2. The sheet-like member 39 is nonmagnetic.

(Magnetic sensor)
The magnetic sensor 9 includes a sensor substrate 40 that faces the magnetic scale 8 from a direction orthogonal to the axis L in a posture parallel to the axis L. The magnetic sensor 9 includes a first magnetoresistive element (first magnetic detecting element) 41 for detecting a linear motion position formed on a substrate surface 40a facing the magnetic scale 8 in the sensor substrate 40, and a first rotating sensor for detecting a rotational position. Two magnetoresistive elements (second magnetic detection elements) 42 are provided.

(First magnetoresistive element)
FIG. 5 is an explanatory diagram of the magnetic sensor 9. 5A shows the magnetic scale 8 when viewed from the axial direction X and the first magnetoresistive element 41 when the first magnetoresistive element 41 is formed as a single layer on the substrate surface 40a. FIG. 5A is an explanatory diagram of the positional relationship between the sensor substrate 40 and the upper right diagram in FIG. 5A shows the arrangement of the magnetoresistive pattern when the first magnetoresistive element 41 is formed as a single layer on the substrate surface 40a. It is explanatory drawing. 5A shows the magnetic scale 8 when viewed from the axial direction X and the second magnetoresistive element 42 when the second magnetoresistive element 42 is formed as a single layer on the substrate surface 40a. FIG. 5A is an explanatory diagram of the positional relationship between the sensor substrate 40 and the lower right diagram in FIG. 5A shows the arrangement of the magnetoresistive pattern when the second magnetoresistive element 42 is formed as a single layer on the substrate surface 40a. It is explanatory drawing.

FIG. 5B shows the left side of the upper stage, in the case where the first magnetoresistive element 41 is formed in two layers on the substrate surface 40a, the magnetic scale 8 when viewed from the axial direction X, and the first magnetoresistive element 41. FIG. 5B is an explanatory diagram of the positional relationship between the sensor substrate 40 and the upper middle diagram of FIG. 5B shows the arrangement of the magnetoresistive pattern when the first magnetoresistive element 41 is formed in two layers on the substrate surface 40a. FIG. 5B is an explanatory diagram, and the diagram on the right side of the upper stage of FIG. 5B schematically illustrates the cross section of the first magnetoresistive element 41 taken along the line XX in the center diagram of the upper stage of FIG. FIG. FIG. 5B shows a diagram on the left side of the lower stage, where the second magnetoresistive element 42 is formed in two layers on the substrate surface 40a, and the magnetic scale 8 when viewed from the axial direction X, and the second magnetoresistive element 42. FIG. 5B is an explanatory diagram of the positional relationship between the sensor substrate 40 and the lower middle diagram of FIG. 5B shows the arrangement of the magnetoresistive pattern when the second magnetoresistive element 42 is formed in two layers on the substrate surface 40a. FIG. 5B is an explanatory diagram, and the diagram on the right side of the lower stage of FIG. 5B schematically shows a cross section of the second magnetoresistive element 42 along the YY line in the center diagram of the lower stage of FIG. FIG. 5 (c) shows the magnetic scale 8 when viewed from the axial direction X and the first magnetoresistive element 41 when the first magnetoresistive element 41 and the second magnetoresistive element 42 are stacked. FIG. 5C is an explanatory diagram of the positional relationship between the second magnetoresistive element 42 and the sensor substrate 40, and the diagram on the right side of FIG. 5C shows the arrangement of the first magnetoresistive element 41 and the second magnetoresistive element 42 on the substrate surface 40a. It is explanatory drawing of. FIG. 6 is an explanatory diagram of a circuit formed by the magnetoresistive elements 41 and 42.

  The first magnetoresistive element 41 has its magnetic sensing direction in the axial direction X. Therefore, the first magnetoresistive element 41 includes a plurality of magnetized patterns 37 of the magnetic scale 8 and a plurality of rows of axial tracks 37a extending in the axial direction X with S poles and N poles alternately arranged around the axis θ. The change in the magnetic field when the magnetic scale 8 moves is detected. Here, in the plurality of axial tracks 37a, the first magnetoresistive element 41 rotates at a boundary portion (a portion where the N pole and the S pole are adjacent) between two axial tracks 37a adjacent to each other around the axis θ. Detect magnetic field. The first magnetoresistive element 41 detects a rotating magnetic field using the saturation sensitivity region of the magnetoresistive element. In other words, the first magnetoresistive element 41 detects a rotating magnetic field in which the direction in the in-plane direction changes at the boundary portion by applying a magnetic field intensity at which the resistance value is saturated while applying a current to a magnetoresistive pattern described later. .

  The first magnetoresistive element 41 includes an A-phase first magnetoresistive pattern SIN and a B-phase first magnetoresistive pattern COS that detect linear movement of the magnetic scale 8 with a phase difference of 90 ° from each other. In other words, the sensor substrate 40 has the A-phase first magnetoresistive pattern SIN and the B-phase first magnetoresistive pattern COS at positions where the same wavelength obtained from the magnetic scale 8 can be detected with a phase difference of 90 °. Prepare.

  The A-phase first magnetoresistive pattern SIN includes a + a-phase first magnetoresistive pattern SIN + that detects a direct movement of the magnetic scale 8 with a phase difference of 180 °, and a −a-phase first magnetoresistive pattern SIN−. Is provided. Similarly, the B-phase first magnetoresistive pattern COS detects + b-phase first magnetoresistive pattern COS + and -b-phase first magnetoresistive pattern COS-, which detects the direct movement of the magnetic scale 8 with a phase difference of 180 °. With. In other words, the + a phase first magnetoresistive pattern SIN + and the + b phase first magnetoresistive pattern COS + are located on the sensor substrate 40 at positions where the same wavelength obtained from the magnetic scale 8 can be detected with a phase difference of 90 °. Is formed. The -a phase first magnetoresistive pattern SIN- and the -b phase first magnetoresistive pattern COS- detect the same wavelength obtained from the magnetic scale 8 on the sensor substrate 40 with a phase difference of 90 [deg.]. It is formed in a possible position.

  As shown in the upper right diagram in FIG. 5A, the first magnetoresistive pattern SIN + of + a phase, the first magnetoresistive pattern COS + of + b phase, the first magnetoresistive pattern SIN− of -a phase, -b The first magnetoresistive pattern COS− of the phase can be formed as a single layer on the substrate surface 40a in an arrangement in which the first magnetoresistive patterns SIN +, SIN−, COS +, and COS− do not overlap each other.

On the other hand, in this example, the A-phase first magnetoresistive pattern SIN (SIN +, SIN−) and the B-phase first magnetoresistive pattern COS (COS +, COS−) are superimposed on the sensor substrate 40 in two layers. ing.

  More specifically, as shown in the upper center and right diagrams of FIG. 5B, a + b phase first magnetoresistive pattern COS + is formed on the substrate surface 40a of the sensor substrate 40, and a + a phase is formed thereon. The first magnetoresistive pattern SIN + is stacked. Further, the -a phase first magnetoresistance pattern SIN- is formed on the substrate surface 40a of the sensor substrate 40, and the -b phase first magnetoresistance pattern COS- is laminated thereon. The stacking relationship between the + a phase first magnetoresistance pattern SIN + and the + b phase first magnetoresistance pattern COS + may be reversed. Also, the stacking relationship between the first magnetoresistive pattern SIN- of the -a phase and the first magnetoresistive pattern COS- of the -b phase may be reversed.

  If the A-phase first magnetoresistive pattern SIN and the B-layer first magnetoresistive pattern COS constituting the first magnetoresistive element 41 are stacked on the sensor substrate 40, the A-phase first magnetoresistive on the sensor substrate 40 The degree of freedom of arrangement of the pattern SIN and the first magnetoresistive pattern COS of the B layer is increased. Therefore, as compared with the case where the first magnetoresistive pattern SIN (SIN +, SIN−) of A phase and the first magnetoresistive pattern COS (COS +, COS−) of B phase are formed on the sensor substrate 40 without being stacked. The first magnetoresistive element 41 can be made small.

  In this example, the A-phase first magnetoresistive pattern SIN and the B-layer first magnetoresistive pattern COS constituting the first magnetoresistive element 41 are stacked on the sensor substrate 40, thereby making the θ around the axis of the magnetic scale 8. The width W1 of the first magnetoresistive element 41 in the direction corresponding to is compared with the height H1 of the first magnetoresistive element 41 in the direction corresponding to the axial direction X of the magnetic scale 8 (see the upper part of FIG. 5B). And shortened. In this example, the center in the width direction of the first magnetoresistive element 41 is disposed at a position facing the apex of the curvature of the magnetized pattern 37 provided on the circumferential surface of the cylindrical magnetic scale 8. .

  Here, the magnetized pattern 37 in which the first magnetoresistive element 41 detects a change in the magnetic field is provided on the circumferential surface of the cylindrical magnetic scale 8. Therefore, when the sensor substrate 40 is placed in a posture parallel to the axis L and opposed to the circumferential surface of the magnetic scale 8, the gap G between the first magnetoresistive pattern and the sensor substrate 40 is about the axis θ (circumferential direction). It changes with. Therefore, by reducing the width W1 of the first magnetoresistive element 41 in the direction corresponding to the axis θ around the magnetic scale 8, the output from the first magnetoresistive element 41 is between the magnetic scale 8 and the sensor substrate 40. It is possible to suppress the influence of the magnetic strength portion due to the gap fluctuation accompanying the curvature of the.

The sensor substrate 40 is made of glass or silicon. The first magnetoresistive patterns SIN− and COS + provided on the substrate surface 40a are formed by laminating a magnetic film such as ferromagnetic NiFe on the substrate surface 40a by a semiconductor process. The second magnetoresistive patterns COS- and SIN +, which are superimposed on the first magnetoresistive patterns SIN− and COS +, form an inorganic insulating layer such as SiO ₂ on the first magnetoresistive patterns. And it forms by laminating | stacking magnetic body films, such as ferromagnetic material NiFe, on this inorganic insulating layer.

  Here, FIG. 6 is a circuit diagram formed by the magnetoresistive patterns SIN +, SIN−, COS +, and COS− of the first magnetoresistive element 41. The first magnetoresistive pattern SIN + of + a phase and the first magnetoresistive pattern SIN− of -a phase constitute a bridge circuit as shown in FIG. 6A, and one end thereof is a power supply terminal (Vcc ) And the other end is connected to the ground terminal (GND). Further, a terminal + a from which the + a phase is output is provided at the midpoint position of the + a phase first magnetoresistive pattern SIN +, and a −a phase first magnetoresistive pattern SIN− is provided at the midpoint position of −a phase. A terminal -a from which the phase is output is provided. Therefore, if the outputs from the terminal + a and the terminal -a are input to the subtracter, a sine wave differential output with less distortion can be obtained.

  Similarly, the + b-phase magnetoresistive pattern COS + and the -b-phase magnetoresistive pattern COS- constitute a bridge circuit as shown in FIG. 6B, and one end thereof is a power supply terminal (Vcc). The other end is connected to the ground terminal (GND). A + b phase output terminal + b is provided at the midpoint position of the + b phase magnetoresistive pattern COS +, and a −b phase output terminal is provided at the midpoint position of the −b phase magnetoresistive pattern COS−. -B is provided. Therefore, if the outputs from the terminal + b and the terminal -b are input to the subtracter, a sine wave differential output with less distortion can be obtained.

(Second magnetoresistive element)
The second magnetoresistive element 42 has its magnetic sensing direction oriented around the axis line θ (circumferential direction). Therefore, the second magnetoresistive element 42 has the magnetization pattern 37 of the magnetic scale 8 in the axial direction X with the circumferential track 37b extending in the axial direction θ by alternately arranging the S and N poles around the axial line θ. As having a plurality of rows, a change in the magnetic field when the magnetic scale 8 rotates is detected. Further, the second magnetoresistive element 42 is a rotating magnetic field generated at a boundary portion (a portion where the N pole and the S pole are adjacent) between two circumferential tracks 37b adjacent in the axial direction X in the plurality of circumferential tracks 37b. Is detected. Further, the second magnetoresistive element 42 detects the rotating magnetic field using the saturation sensitivity region of the magnetoresistive element. That is, the second magnetoresistive element 42 detects a rotating magnetic field in which the direction in the in-plane direction changes at the boundary portion by applying a magnetic field intensity at which the resistance value is saturated while passing a current through a magnetoresistive pattern to be described later. .

  The second magnetoresistive element 42 includes an A-phase second magnetoresistive pattern SIN and a B-phase second magnetoresistive pattern COS that detect the rotation of the magnetic scale 8 with a phase difference of 90 ° from each other. In other words, the sensor substrate 40 has the A-phase second magnetoresistive pattern SIN and the B-phase second magnetoresistive pattern COS at positions where the same wavelength obtained from the magnetic scale 8 can be detected with a phase difference of 90 °. Prepare.

  The A-phase second magnetoresistance pattern SIN includes a + a-phase second magnetoresistance pattern SIN + that detects the rotation of the magnetic scale 8 with a phase difference of 180 °, and a -a-phase second magnetoresistance pattern SIN-. Prepare. Similarly, the B-phase second magnetoresistance pattern COS includes a + b-phase second magnetoresistance pattern COS + that detects the rotation of the magnetic scale 8 with a phase difference of 180 °, and a -b-phase second magnetoresistance pattern COS-. Is provided. That is, the + a phase second magnetoresistance pattern SIN + and the + b phase second magnetoresistance pattern COS + are located on the sensor substrate 40 at positions where the same wavelength obtained from the magnetic scale 8 can be detected with a phase difference of 90 °. Is formed. The -a phase second magnetoresistance pattern SIN- and the -b phase second magnetoresistance pattern COS- detect the same wavelength obtained from the magnetic scale 8 on the sensor substrate 40 with a phase difference of 90 [deg.]. It is formed in a possible position.

  5A, the + a phase second magnetoresistance pattern SIN +, the + b phase second magnetoresistance pattern COS +, the −a phase second magnetoresistance pattern SIN−, −b The second magnetoresistive pattern COS− of the phase can be formed as a single layer on the substrate surface 40a in an arrangement in which the second magnetoresistive patterns SIN +, SIN−, COS +, and COS− do not overlap each other. The + a-phase second magnetoresistance pattern SIN +, the + b-phase second magnetoresistance pattern COS +, the -a-phase second magnetoresistance pattern SIN-, and the -b-phase second magnetoresistance pattern COS- are applied to the substrate surface 40a. When the single-layered magnetoresistive pattern is formed, the + m phase first magnetoresistive pattern SIN +, the + b phase first magnetoresistive pattern COS +, and the −a phase first magnetoresistive pattern SIN−, −b. When the first magnetoresistive pattern COS- of the phase is formed as a single layer on the substrate surface 40a, each magnetoresistive pattern (see the figure on the right side of the upper stage of FIG. 5A) is rotated by 90 ° in the in-plane direction. Is the same arrangement relationship.

  On the other hand, in this example, the A-phase second magnetoresistive pattern SIN (SIN +, SIN−) and the B-phase second magnetoresistive pattern COS (COS +, COS−) are stacked on the sensor substrate 40 in two layers. ing.

  More specifically, as shown in the lower center and right diagrams of FIG. 5B, the second magnetoresistive pattern SIN− of the −a phase is formed on the substrate surface 40 a of the sensor substrate 40, and And a second magnetoresistive pattern COS + of + b phase is laminated. Further, a -b phase second magnetoresistance pattern COS- is formed on the substrate surface 40a of the sensor substrate 40, and a + a phase second magnetoresistance pattern SIN + is laminated thereon. Note that the stacking relationship between the −a phase second magnetoresistance pattern SIN− and the + b phase second magnetoresistance pattern COS + may be reversed. The stacking relationship between the + a phase second magnetoresistance pattern SIN + and the −b phase second magnetoresistance pattern COS− may be reversed.

  If the second magnetoresistive pattern SIN of the A phase and the second magnetoresistive pattern COS of the B layer constituting the second magnetoresistive element 42 are laminated on the sensor substrate 40, the second magnetoresistive of the A phase on the sensor substrate 40 is obtained. The degree of freedom of arrangement of the pattern SIN and the second magnetoresistive pattern COS of the B layer is increased. Therefore, as compared with the case where the second magnetic resistance pattern SIN (SIN +, SIN−) of the A phase and the second magnetic resistance pattern COS (COS +, COS−) of the B phase are formed on the sensor substrate 40 without being stacked. The second magnetoresistive element 42 can be made small. As a result, the sensor substrate 40 can be miniaturized, and the linear motion rotation detector 7 can be made smaller.

  In this example, the A-phase second magnetoresistive pattern SIN and the B-layer second magnetoresistive pattern COS constituting the second magnetoresistive element 42 are stacked on the sensor substrate 40, so that the θ around the axis of the magnetic scale 8 is θ. Is compared with the height H2 of the second magnetoresistive element 42 in the direction corresponding to the axial direction X of the magnetic scale 8 (see the lower part of FIG. 5B). And shortened. In this example, the center in the width direction of the second magnetoresistive element 42 is arranged at a position facing the apex of the curvature of the magnetized pattern 37 provided on the circumferential surface of the cylindrical magnetic scale 8. .

  Here, the magnetized pattern 37 for detecting the change of the magnetic field by the second magnetoresistive element 42 is provided on the circumferential surface of the cylindrical magnetic scale 8. Therefore, when the sensor substrate 40 is placed in a posture parallel to the axis L and opposed to the circumferential surface of the magnetic scale 8, the gap G between the second magnetoresistive pattern and the sensor substrate 40 is about the axis θ (circumferential direction). It changes with. Therefore, by reducing the width W2 of the second magnetoresistive element 42 in the direction corresponding to the axis θ around the magnetic scale 8, the output from the second magnetoresistive element 42 is between the magnetic scale 8 and the sensor substrate 40. It is possible to suppress the influence of the magnetic strength portion due to the gap fluctuation accompanying the curvature of the.

As for the second magnetoresistive element 42, as with the first magnetoresistive element 41, the first magnetoresistive patterns SIN- and COS- provided on the substrate surface 40a are strongly applied to the substrate surface 40a by a semiconductor process. It is formed by laminating magnetic films such as magnetic NiFe. The second magnetoresistive patterns COS + and SIN +, which are superimposed on the first magnetoresistive patterns SIN− and COS−, form an inorganic insulating layer such as SiO ₂ on the first magnetoresistive patterns. And it forms by laminating | stacking magnetic body films, such as ferromagnetic material NiFe, on this inorganic insulating layer.

  The second magnetoresistive element 42 has a circuit configuration similar to that of the first magnetoresistive element 41. Since the circuit configuration of the second magnetoresistive element 42 is the same as that shown in FIG. 6, its detailed description is omitted.

(First and second magnetoresistive elements)
Here, in this example, as shown in FIG. 5C, the first magnetoresistive element 41 and the second magnetoresistive element 42 are further stacked on the sensor substrate 40. That is, on the sensor substrate 40, the A-phase first magnetoresistive pattern SIN and the B-layer first magnetoresistive pattern COS constituting the first magnetoresistive element 41 are stacked in two layers, and above or below the first magnetoresistive pattern COS. The second magnetoresistive pattern of the A phase and the second magnetoresistive pattern COS of the B layer constituting the two magnetoresistive elements 42 are overlapped in two layers. Therefore, in this example, the formation area of the first magnetoresistive element 41 and the second magnetoresistive element 42 on the sensor substrate 40 can be reduced. Thereby, since the sensor board | substrate 40 can be made small, it becomes possible to make the linear motion rotation detector 7 small.

  Further, in the stacking, the first magnetoresistive element 41 and the second magnetoresistive element 42 have their centers in the width direction (direction corresponding to the axis θ around the magnetic scale 8) coincided. Therefore, in the stacked first magnetoresistive element 41 and second magnetoresistive element 42, the width W in the direction corresponding to the axial direction θ of the magnetic scale 8 is the first width in the direction corresponding to the axial direction X of the magnetic scale 8. It is shorter than the height H of the magnetoresistive element 41. Further, the center in the width direction of the laminated first magnetoresistive element 41 and second magnetoresistive element 42 is opposed to the apex of the curvature of the magnetized pattern 37 provided on the circumferential surface of the cylindrical magnetic scale 8. Placed in position. Therefore, it is possible to suppress the influence of the magnetic strength portion due to the gap fluctuation caused by the curvature between the magnetic scale 8 and the sensor substrate 40 for the outputs of the first magnetoresistive element 41 and the second magnetoresistive element 42.

(Optical sensor)
Next, the optical sensor 10 will be described with reference to FIGS. 4 and 7. FIG. 7 is an explanatory diagram of a positional relationship among the magnetic scale 8, the magnetic sensor 9, and the optical sensor 10. The optical sensor 10 is a photo reflector. As shown in FIG. 7, the optical sensor 10 is mounted on the circuit board 50. The circuit board 50 and the sensor board 40 are arranged in parallel and are connected by a flexible printed board 51. The circuit board 50 is located farther from the magnetic scale 8 than the sensor board 40. Therefore, the optical sensor 10 is further away from the magnetic scale 8 than the first magnetoresistive element 41 and the second magnetoresistive element 42.

  As shown in FIG. 4, the optical sensor 10 includes a light emitting unit 54 that emits detection light and a detection unit 55 that receives reflected light of the detection light from the reflection pattern 38. In the optical sensor 10, the light emitting unit 54 is located behind the detecting unit 55 in the rotation direction θ <b> 1 around the axis of the magnetic scale 8. Therefore, when the reflection pattern 38 passes through the detection position by the optical sensor 10, the reflection pattern 38 passes through the position facing the light emitting unit 54 and then passes the position facing the detection unit 55. By arranging the photosensor 10 in such a manner, the gap characteristic depending on the distance between the photosensor 10 and the reflection pattern 38 is improved. That is, even when the distance between the optical sensor 10 and the reflection pattern 38 is deviated from the target distance, the output from the optical sensor 10 can be suppressed from fluctuating.

  Further, in the optical sensor 10, the detection unit 55 passes through the center of the first magnetoresistive element 41 and the second magnetoresistive element 42 in the width direction and overlaps the virtual plane M including the axis L. Further, the detection unit 55 of the optical sensor 10 faces the apex of the curvature of the magnetic scale 8.

  The reflection pattern 38 has an output from the first magnetoresistive pattern SIN of the A phase of the second magnetoresistive element 42 that detects the rotation of the magnetic scale 8 in the magnetized pattern 37, and the B phase first 1 is attached at a position where the output from the magnetoresistive pattern COS is maximized (Arctan = 0 °). Here, when the reflection pattern 38 passes the detection position of the optical sensor 10, the detection unit 55 receives the reflected light of the inspection light. Thereby, a rectangular analog signal is output from the optical sensor 10. Therefore, in the linear motion rotation detector 7, the origin position around the axis θ can be acquired.

(Function and effect)
According to the linear motion rotation detector 7 of this example, the linear motion position and the rotational position can be detected using the magnetic scale 8. Therefore, it is not necessary to arrange the linear motion scale and the rotation scale in the axial direction X. In addition, since the first magnetoresistive element 41 and the second magnetoresistive element can be arranged to oppose the magnetized pattern 37 provided on one magnetic scale 8, the first magnetoresistive element 41, the second magnetoresistive element 42, Can be arranged at the same position in the axial direction X. Therefore, the linear rotation detector 7 can be prevented from being enlarged in the axial direction X.

  In this example, the A-phase first magnetoresistive pattern SIN and the B-layer first magnetoresistive pattern COS constituting the first magnetoresistive element 41 are laminated on the sensor substrate 40. The degree of freedom of arrangement of the first magnetoresistive pattern SIN of the A phase and the first magnetoresistive pattern COS of the B layer is increased. Similarly, the A-phase second magnetoresistive pattern SIN and the B-layer second magnetoresistive pattern COS constituting the second magnetoresistive element 42 are stacked on the sensor substrate 40, so that the A-phase on the sensor substrate 40 is The degree of freedom of arrangement of the second magnetoresistive pattern SIN and the second magnetoresistive pattern COS of the B layer is increased. Furthermore, in this example, the first magnetoresistive element 41 and the second magnetoresistive element 42 are stacked on the sensor substrate 40. Therefore, in each of the magnetoresistive elements 41 and 42, the A-phase magnetoresistive pattern SIN (SIN +, SIN−) and the B-phase magnetoresistive pattern COS (COS +, COS−) are formed on the sensor substrate 40 without being stacked. In this case, the magnetic sensor 99 can be made smaller than in the case where the first magnetoresistive element 41 and the second magnetoresistive element 42 are formed on the sensor substrate 40 without being stacked.

  Further, in this example, the A-phase first magnetoresistive pattern SIN and the B-layer first magnetoresistive pattern COS constituting the first magnetoresistive element 41 are stacked on the sensor substrate 40, thereby the axis of the magnetic scale 8. The width W 1 of the first magnetoresistive element 41 in the direction corresponding to the rotation θ is made shorter than the height H 1 of the first magnetoresistive element 41 in the direction corresponding to the axial direction X of the magnetic scale 8. The center of the first magnetoresistive element 41 in the width direction is arranged at a position facing the apex of the curvature of the magnetized pattern 37 provided on the circumferential surface of the cylindrical magnetic scale 8. Further, the A-phase second magnetoresistive pattern SIN and the B-layer second magnetoresistive pattern COS constituting the second magnetoresistive element 42 are stacked on the sensor substrate 40 to correspond to the axis θ around the magnetic scale 8. The width W <b> 2 of the second magnetoresistive element 42 in the direction to be reduced is shorter than the height H <b> 2 of the second magnetoresistive element 42 in the direction corresponding to the axial direction X of the magnetic scale 8. The center of the second magnetoresistive element 42 in the width direction is disposed at a position facing the apex of the curvature of the magnetized pattern 37 provided on the circumferential surface of the cylindrical magnetic scale 8. Therefore, it is possible to suppress the influence of the magnetic strength portion due to the gap fluctuation caused by the curvature between the magnetic scale 8 and the sensor substrate 40 for the outputs of the first magnetoresistive element 41 and the second magnetoresistive element 42.

  Here, if the influence of the magnetic strength portion caused by the gap fluctuation caused by the curvature between the magnetic scale 8 and the sensor substrate 40 is suppressed, the output is performed from each of the first magnetoresistive element 41 and the second magnetoresistive element 42. The quality of the analog signal is improved. That is, an output close to an ideal sine wave can be obtained as an analog signal. Further, with respect to each of the first magnetoresistive element 41 and the second magnetoresistive element 42, if the widths W1 and W2 in the direction corresponding to the axis around the magnetic scale 8 are reduced, the magnetic scale 8 is reduced in diameter (reduced in diameter). )it can. Therefore, the linear motion rotation detector 7 can be reduced in size.

  Further, in this example, the origin position of θ around the axis is optically detected using the reflection pattern 38 provided on the magnetic scale 8. That is, the reflected light of the inspection light from the reflection pattern 38 provided on the magnetic scale 8 is detected by the optical sensor 10 to acquire the origin position. Therefore, it is not necessary to calculate outputs from a plurality of detectors in order to detect the origin position, and the origin position can be easily detected.

  Further, in this example, the reflection pattern 38 for detecting the origin position and the magnetization pattern 37 on the magnetic scale 8 are provided at the overlapping position. Therefore, even when the reflection pattern 38 is provided on the magnetic scale 8, the linear motion rotation detector 7 does not increase in size in the axial direction X.

  Further, the reflective pattern 38 is provided on the magnetic scale 8 by sticking a sheet-like member 39 including the reflective pattern 38 to the surface of the magnetized pattern 37. Therefore, it is easy to provide the reflective pattern 38. Here, the reflective pattern 38 extends on the surface of the magnetized pattern 37 with a constant width in the axial direction X. Therefore, even when the magnetic scale 8 moves in the axial direction X, the optical sensor 10 can detect the origin position around the axis θ.

  In addition, the circuit board 50 on which the optical sensor 10 is mounted is located farther from the magnetic scale 8 than the sensor board 40. Therefore, the optical sensor 10 is further away from the magnetic scale 8 than the first magnetoresistive element 41 and the second magnetoresistive element 42. Therefore, it is easy to arrange the sensor substrate 40 including the first magnetoresistive element 41 and the second magnetoresistive element 42 and the optical sensor 10.

  Further, in this example, the center in the width direction of the first magnetoresistive element 41, the center in the width direction of the second magnetoresistive element 42, and the detection unit 55 of the optical sensor 10 overlap the virtual plane M including the axis L. , Facing the apex of the curvature of the magnetic scale 8. Therefore, an accurate origin position can be acquired based on the output from the optical sensor 10.

(Modification 1)
In the above example, the magnetic scale 8 is provided with a reflection pattern for detecting the origin position around the axis θ, but the reflection pattern is for detecting the origin position in the axial direction X. It may be provided. FIG. 8 is an explanatory diagram of a linear motion rotation detector 7A of Modification 1 provided with a reflection pattern for detecting the origin position in the axial direction X. FIG. 8A shows a state in which the linear motion rotation detector 7A has detected the first origin position in the first direction X1 in the axial direction X, and FIG. 8B shows the linear motion rotation detector 7A in the axial direction X. The state which detected the 2nd origin position of the 2nd direction X2 is shown. The linear motion rotation detector 7A of the present example is the same as the linear motion rotation detector 7 except for the reflection pattern 38 and the optical sensor 10. Therefore, the reflective pattern 38 and the optical sensor 10 will be described, and other description will be omitted.

  In this example, the reflection pattern 38 extends around the surface of the magnetized pattern 37 with a constant width around the axis θ. The reflection pattern 38 extends over the entire circumference of the magnetic scale 8 (magnetization pattern 37). Furthermore, in this example, as the reflective pattern 38, the first direction side reflective pattern 38a for detecting the first origin position 8A in the first direction X1 in the axial direction X, and the second direction opposite to the first direction X1. A second direction side reflection pattern 38b for detecting the second origin position 8B of X2 is provided. In this example, as the optical sensor 10, the first optical sensor 10a that detects the reflected light of the inspection light from the first direction side reflection pattern 38a and the reflected light of the inspection light from the second direction side reflection pattern 38b are used. A second optical sensor 10b for detection is provided.

In this example, as shown in FIG. 8A, when the magnetic scale 8 is at the first origin position 8A in the first direction X1, the first photosensor 10a emits the inspection light from the first direction side reflection pattern 38a. The reflected light of is detected. On the other hand, as shown in FIG. 8B, when the magnetic scale 8 is at the second origin position 8B in the second direction X2, the second photosensor 10b receives the inspection light from the second direction side reflection pattern 38b. Detect reflected light. Therefore, according to the linear motion rotation detector 7A of the present example, the origin position 8A in the first direction X1 in the axial direction X of the magnetic scale 8 and the origin position 8B in the second direction X2 can be detected. Further, since the reflection patterns 38a and 38b extend on the surface of the magnetized pattern 37 with a constant width around the axis θ, even when the magnetic scale 8 is rotated around the axis θ, the optical sensors 10a and 10b can perform the axial direction. X origin positions 8A and 8B can be detected.

  Note that the second direction side reflection pattern 38b and the second optical sensor 10b may be omitted, and detection is possible only when the magnetic scale 8 is at the first origin position 8A. Further, the first direction side reflection pattern 38a and the first optical sensor 10a may be omitted, and detection may be made only when the magnetic scale 8 is at the second origin position 8B.

(Modification 2)
FIG. 9 shows a modified example in which a reflection pattern part for detecting the origin position around the axis θ and a reflection pattern part for detecting the origin position in the axial direction X are provided on the magnetic scale 8. It is explanatory drawing of 2 linear motion rotation detector 7B. In the linear motion rotation detector 7B of the present example, the configuration other than the reflection pattern 38 and the optical sensor 10 is the same as that of the linear motion rotation detector 7 described above. Therefore, the reflective pattern 38 and the optical sensor 10 will be described, and other description will be omitted.

  In this example, the reflection pattern 38 includes a first reflection pattern portion 61 for detecting the origin position around the axis θ and a second reflection pattern portion 62 for detecting the origin position in the first direction X1 in the axis direction X. And a third reflection pattern portion 63 for detecting the origin position in the second direction X1 of the axial direction X. The first reflection pattern portion 61 extends on the surface of the magnetized pattern 37 with a constant width in the axial direction X. The first reflection pattern portion 61 is the same as the reflection pattern 38 provided on the magnetic scale 8 of the linear motion rotation detector 7. The second reflection pattern portion 62 and the third reflection pattern portion 63 extend with a constant width around the axis θ around the surface of the magnetized pattern 37. The second reflection pattern portion 62 and the third reflection pattern portion 63 are the same as the reflection patterns 38a and 38b provided on the magnetic scale 8 of the linear motion rotation detector 7A.

  In this example, as the optical sensor 10, the first optical sensor 10 a that detects the reflected light of the inspection light from the first reflective pattern portion 61 and the second reflective pattern portion 62, the first reflective pattern portion 61, and the third reflective sensor. A second optical sensor 10b that detects the reflected light of the inspection light from the reflective pattern portion 63 is provided.

  In this example, similarly to the linear motion rotation detector 7A, the first origin position 8A of the magnetic scale 8 is acquired when the first optical sensor 10a detects the reflected light of the inspection light from the second reflective pattern portion 62. (See FIG. 8A). When the second optical sensor 10b detects the reflected light of the inspection light from the third reflection pattern portion 63, the second optical sensor 10b acquires the second origin position 8B of the magnetic scale 8 (see FIG. 8B). When both the first optical sensor 10a and the second optical sensor 10b detect the reflected light of the inspection light from the first reflective pattern portion 61, the origin position around the axis line θ is acquired. According to this example, the reflection pattern 38 provided on the magnetic scale 8 can exclusively detect one of the origin position around the axis θ and the origin position in the axis direction X.

(Other embodiments)
The reflection pattern 38 may include a first reflection pattern portion and a second reflection pattern portion having a lower reflectance than the first reflection pattern portion. In this case, the optical sensor 10 detects the reflected light of the inspection light from the first reflection pattern portion.

That is, in each of the above examples, the entire surface of the sheet-like member 39 is a reflective pattern having a high reflectance, but as the sheet-like member 39, a material wider in the width direction than the above example is used. The first reflection pattern 38 and the second reflection pattern 38 having different reflectivities are provided on the surface, and the reflected light from the first reflection pattern 38 having a high reflectivity can be detected by the optical sensor 10. For example, the second reflective pattern 38 is provided by printing on the surface of the sheet-like member 39 made of metal foil or the like with black ink or the like, and an area where printing is not performed is defined as the first reflective pattern 38. In this way, the reflection pattern can be accurately provided on the surface of the sheet-like member 39.

  In the above example, the magnetic sensor 9 includes the magnetoresistive elements (the first magnetoresistive element 41 and the second magnetoresistive element 42), but a Hall element can be used instead of the magnetoresistive element.

7 · 7A · 7B ··· Direct rotation detector 8 ··· Magnetic scale 8A ··· First origin position 8B ··· Second origin location 10 ··· Optical sensor 37 ··· Magnetized pattern 38 · ..Reflection pattern 38a ... first direction side reflection pattern 38b ... second direction side reflection pattern 39 ... sheet-like member 40 ... sensor substrate 41 ... first magnetoresistive element (first magnetism) Detection element)
42 ... 2nd magnetoresistive element (2nd magnetic sensing element)
55... Detection unit 61... First reflection pattern portion 62... Second reflection pattern portion L... Axis line M... Virtual plane X ... Axis direction X1. ..Second direction

Claims (9)

A cylindrical magnetic scale that moves in the axial direction and rotates around the axis;
A first magnetic detecting element for detecting a linear motion position;
A second magnetic detection element for detecting the rotational position;
A reflection pattern for detecting an origin position of at least one of the axial direction and around the axial line;
An optical sensor including a detection unit that detects reflected light of inspection light from the reflective pattern;
The magnetic scale has a lattice shape in which S-poles and N-poles are alternately arranged in the axial direction on the circumferential surface around the axis, and S-poles and N-poles are alternately magnetized around the axis. With a magnetized pattern of
The first magnetic detection element and the second magnetic detection element are disposed to face the magnetization pattern,
The linear motion rotation detector, wherein the reflection pattern is provided at a position overlapping the magnetized pattern on the magnetic scale. In claim 1,
A sheet-like member provided with the reflective pattern;
The linear rotation detector, wherein the sheet-like member is attached to a surface of the magnetized pattern in the magnetic scale. In claim 1 or 2,
The linear motion rotation detector, wherein the reflection pattern is for detecting an origin position around the axis, and the surface of the magnetized pattern extends with a constant width in the axis direction. In claim 1 or 2,
The linear motion rotation detector, wherein the reflection pattern is for detecting an origin position in the axial direction, and extends on the surface of the magnetized pattern with a constant width around the axis. In claim 4,
As the reflection pattern, a first direction side reflection pattern for detecting a first origin position in the first direction in the axial direction and a second origin position in a second direction opposite to the first direction are detected. And a second direction side reflection pattern of
The optical sensor includes a first optical sensor that detects the reflected light from the first direction-side reflection pattern, and a second optical sensor that detects the reflected light from the second direction-side reflection pattern. A linear motion rotation detector. In claim 2,
The reflection pattern includes a first reflection pattern portion for detecting an origin position around the axis, and a second reflection pattern portion for detecting an origin position in the axis direction,
The first reflection pattern portion extends on the surface of the magnetization pattern with a constant width in the axial direction,
The linear motion rotation detector, wherein the second reflection pattern portion extends on the surface of the magnetized pattern with a constant width around an axis. In any one of claims 1 to 6,
A sensor substrate including the first magnetic detection element and the second magnetic detection element;
The first magnetic detection element is a magnetoresistive element, and includes a first magnetoresistive pattern of A phase and a first magnetoresistive pattern of B phase that detect linear motion of the magnetic scale with a phase difference of 90 ° with each other,
The second magnetic sensing element is a magnetoresistive element, and includes an A-phase second magnetoresistive pattern and a B-phase second magnetoresistive pattern that detect rotation of the magnetic scale with a phase difference of 90 ° from each other.
The A-phase first magnetoresistive pattern and the B-phase first magnetoresistive pattern are stacked on the sensor substrate,
The linear motion rotation detector, wherein the A-phase second magnetoresistive pattern and the B-phase second magnetoresistive pattern are stacked on the sensor substrate. In claim 7,
The center of the first magnetic detection element in the width direction on the sensor substrate corresponding to the axis of the magnetic scale and the center of the second magnetic detection element in the width direction overlap on the sensor substrate,
The detection unit of the optical sensor passes through the center in the width direction of the first magnetic detection element and the second magnetic detection element and overlaps a virtual plane including the axis,
The linear motion characterized in that the center of the first magnetic detection element in the width direction, the center of the second magnetic detection element in the width direction, and the detection unit face the vertex of curvature of the magnetic scale. Rotation detector. In claim 7 or 8,
The linear motion rotation detector, wherein the detection unit is further away from the surface of the magnetic scale than the first magnetic detection element and the second magnetic detection element.

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