JP2010060339A - Movement detection device using magnet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a movement detection device for detecting the moving position of a magnet by a magnetic detector wherein the magnet can move smoothly together with a movement section, and the positional relation between the magnet and the magnetic detector is stabilized. <P>SOLUTION: A sliding holder 20 which slides on a guideway 14 formed near the magnetic detector 16 is provided, and the magnet 30 is held in the sliding holder 20. The facing surface 33 facing the X1 side of the magnet 30 is a curved surface, and the facing surface 33 protrudes in the X1 direction from an opening 23 formed at the sliding holder 20 while reducing its distance from the magnetic detector 16. A flat spring 40 is provided between the sliding holder 20 and the movement section 12b, and by the flat spring 40, the sliding holder 20 is pressed against the guideway 14. Since the sliding holder 20 slides on the guideway 14 when the movement section 12b moves, the relative distance between the magnet 30 and the magnetic detector 16 can be always optimally set. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a movement detection device used to detect the opening / closing amount of a valve provided in an exhaust gas recirculation device of an internal combustion engine and the movement amount of various device mechanisms, and in particular, a magnet is mounted on a moving part. The present invention relates to a movement detection device in which a magnetic detector for detecting a leakage magnetic field from the magnet is provided in a fixed portion.

  In various devices, a movement detection device including a magnet and a magnetic detector that detects a leakage magnetic field from the magnet is used to detect the movement state of the moving unit. As an example, Patent Document 1 below discloses an opening degree detection device that detects an opening / closing amount of a variable valve provided in a carburetor of an internal combustion engine using a magnetic sensor.

  In this opening degree detection device, a holder provided in the valve chamber reciprocates together with the piston valve. A plastic magnet is fixed to the holder, and the plastic magnet moves in the valve chamber as the piston valve and the holder move. A sensor chamber is integrally formed outside the valve chamber, and three magnetic sensors are provided in the sensor chamber side by side in the moving direction of the plastic magnet. In this opening degree detection device, three magnetic sensors detect the movement position of the plastic magnet, thereby detecting that the piston valve has reached the first opening degree, the second opening degree, or the third opening degree. Is.

  Although the opening degree detection device described in Patent Document 1 can detect the opening degree of the piston valve in three stages using three magnetic sensors, for example, the circulation path of the exhaust gas recirculation device It is difficult to detect the degree of opening and closing of the valve with fine resolution, as required by the opening and closing valve provided in the.

In addition, since the plastic magnet moves directly facing the inner wall of the valve chamber, it is difficult to ensure the facing distance between the plastic magnet and each magnetic sensor with high accuracy. Therefore, when the plastic magnet moves, the detection value from each magnetic sensor may vary. Further, since the plastic magnet moves directly opposite to the inner wall of the valve chamber, there is a possibility that the plastic magnet is worn or damaged by sliding frictional force with the inner wall when moving.
JP 7-317574 A

  The present invention solves the above-described conventional problems, and when the moving unit moves along the guide surface, the relative distance between the magnet provided on the moving unit and the guide surface can always be ensured with high accuracy, An object of the present invention is to provide a movement detection device that can detect the movement position of a moving unit with high accuracy by a magnetic detector.

  Another object of the present invention is to provide a movement detection device that can detect a leakage magnetic field from a magnet with high accuracy by a magnetic detector and can detect a movement amount of a movement position with high resolution.

The present invention provides a moving unit that linearly reciprocates along a guide unit provided in a fixed unit, a magnet that moves together with the moving unit, a leakage magnetic field from the magnet that is installed in the fixed unit. In a movement detection device having a magnetic detector to detect,
The opposing surface of the magnet that faces the magnetic detector has a shape in which an intermediate region protrudes toward the side where the magnetic detector is disposed, rather than both end portions of the moving portion that are directed in the moving direction.
A holder that holds the magnet and moves together with the moving portion is provided, and the holder has an opening formed at least in a portion facing the central region of the facing surface.

  The movement detection device of the present invention uses a magnet having a shape in which the central portion of the opposing surface protrudes toward the side on which the magnetic detector is provided. The relationship with the detection output by the detector can be close to a linear function. And since the opening provided in the holder facing the center part of a magnet is provided, the center part of a magnet can be arrange | positioned in this opening part, and the distance of a magnet and a magnetic detector can be shortened. Therefore, the detection sensitivity of the leakage magnetic field by the magnetic detector can be increased.

  In the present invention, the facing surface of the magnet is a protruding curved surface in which the intermediate region protrudes to the side where the magnetic detector is disposed from both end portions.

  Further, according to the present invention, the holder has a holding recess that opens at a back portion that is the side opposite to the side to which the facing surface faces, and the magnet is inserted into the holding recess from the back portion, and the holding In the recess, the magnet is fixed so as not to move in the moving direction of the moving part.

  In the movement detection apparatus having the above-described configuration, the magnet can be held by the holder by attaching the magnet from the opening of the back portion of the holder, and assembly work can be facilitated.

  In the present invention, the magnet is provided with a contact portion at a position retracted from the facing surface, the holder is provided with a positioning portion in a region other than the opening, and the contact portion is It is preferable that the magnet is positioned in the holder supported by the positioning portion.

  The magnet is provided with an abutting portion that retreats from the facing surface, and the magnet is positioned by abutting the abutting portion against the holder. Therefore, the opposing surface of the projecting shape of the magnet is accurately positioned in the holder. be able to.

  In the present invention, a leaf spring is provided between the moving part and the holder, and the holder is pressed toward the side where the magnetic detector is disposed by the leaf spring, The magnet is directly pressed by an auxiliary pressing piece provided on a leaf spring, and the contact portion is elastically pressed by the positioning portion.

  In the above configuration, the magnet pressing portion is pressed against the positioning portion of the holder by the holding pressing piece provided on the leaf spring, and the magnet can be held without moving in the holder.

  In the movement detecting device of the present invention, the magnet held by the holder that moves together with the moving part has a projecting facing surface, and the holder is formed with an opening that faces the central region of the facing surface of the magnet. ing. Therefore, the opposing surface of a magnet can be arrange | positioned in the position which approaches a magnetic detector, and the detection sensitivity of the leakage magnetic field of the magnet by a magnetic detector can be made high.

  Moreover, even if the opposing surface facing the magnetism detector of the magnet is a curved surface, a contact portion is formed at a position retracted from the protruding opposing surface of the magnet, and the magnet is positioned by this contact portion. The magnet can be reliably positioned in the holder.

  FIG. 1 is a sectional view showing a movement detecting apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing a state in which the leaf spring and the sliding holder are assembled from the back side, and FIG. 3 is an exploded perspective view of the leaf spring, the magnet, and the sliding holder as seen from the back side. FIG. 4 is an exploded perspective view of the magnet and the sliding holder as viewed from the facing surface side. FIG. 5 is a longitudinal sectional view showing the leaf spring and the sliding holder.

  A movement detection device 10 shown in FIG. 1 is for detecting the degree of opening and closing of a control valve 1 that controls the circulation amount of exhaust gas in an exhaust gas recirculation device (EGR) of an internal combustion engine. The control valve is opened and closed by the power of the motor or the like according to a command from a control unit provided in the automobile.

  The movement detection device 10 includes a housing 11 that is a fixed portion. The housing 11 is formed of a non-magnetic material by injection molding with a synthetic resin material. A thrust bearing 13 is attached to the lower portion of the housing 11, and a shaft portion 12a is slidably held in the Y1-Y2 direction on the thrust bearing 13. The shaft portion 12a moves in the Y1-Y2 direction according to the opening degree of the control valve 1 when the control valve 1 opens and closes. A moving part 12 b is integrally formed on the upper part of the shaft part 12 a, and the shaft part 12 a and the moving part 12 b move up and down in the cylinder 11 a inside the housing 11. The shaft portion 12a and the moving portion 12b are formed of a nonmagnetic material such as a synthetic resin material. A compression coil spring 17 is housed in the cylinder 11a. The compression coil spring 17 constantly urges the shaft portion 12a and the moving portion 12b in the Y2 direction. The compression coil spring 17 is made of a nonmagnetic material such as stainless steel for springs.

  A guide portion for linearly moving the moving portion 12b in the Y1-Y2 direction is provided in the cylinder 11a, and the shaft portion 12a and the moving portion 12b are guided by the thrust bearing 13 and the guide portion to be Y1- It is moved linearly in the Y2 direction. A guide surface 14 is formed on the inner surface of the cylinder 11a on the X1 side. The guide surface 14 is a plane extending in the direction orthogonal to the paper surface of FIG. 1 and in the Y1-Y2 direction.

  A holding recess 15 is formed in the housing 11 on the X1 side of the guide surface 14. A magnetic detector 16 is held in the holding recess 15. The magnetic detector 16 is fixed in close contact with the positioning surface 15a on the X2 side of the holding recess 15. The dimension of the guide surface 14 and the positioning surface 15a in the X direction is determined with high accuracy by dimensional control when the housing 11 is manufactured. For this purpose, the distance in the X direction between the magnetic detector 16 in close contact with the positioning surface 15a and the guide surface 14 is set with high accuracy.

  The magnetic detector 16 can detect a change in strength of the magnetic flux in the X1 direction and the X2 direction and a change in the direction thereof, and includes a detection element such as a Hall element or a magnetoresistive effect element.

  As shown in FIG. 1, a sliding holder 20 is provided in the cylinder 11 a, and a magnet 30 is held on the sliding holder 20. A leaf spring 40 is provided between the sliding holder 20 and the moving portion 12 b, and the sliding holder 20 is pressed against the guide surface 14 by the elastic force of the leaf spring 40. When the shaft portion 12a and the moving portion 12b move in the Y1-Y2 direction according to the opening degree of the control valve 1, the sliding holder 20 slides in close contact with the guide surface 14 together with the moving portion 12b.

  As shown in FIGS. 3, 4, and 5, the sliding holder 20 has a thin rectangular parallelepiped shape and is formed of a nonmagnetic material such as a synthetic resin material. As shown in FIG. 4, a pair of rail surfaces 21, 21 are formed on the front side, which is the X1 side (side facing the guide surface 14) of the sliding holder 20. The rail surfaces 21 and 21 are spaced apart on the Z1 side and the Z2 side, and are planes parallel to the YZ plane. Further, each rail surface 21 has a strip shape in which the vertical dimension in the Y1-Y2 direction is sufficiently larger than the width dimension in the Z1-Z2 direction. Each of the rail surfaces 21 and 21 has a curved surface at the end portions 21a and 21a on the Y1 side, and also has curved surfaces at the end portions 21b and 21b on the Y2 side.

  Between the rail surface 21 and the rail surface 21, receding surfaces 22 and 22 that recede to the X2 side from the rail surfaces 21 and 21 are provided. The receding surfaces 22 and 22 are planes parallel to the YZ plane. The receding surface 22 and the receding surface 22 are provided apart in the Y1-Y2 direction, and an opening 23 is formed between the upper receding surface 22 and the lower receding surface. The opening 23 has a rectangular shape, penetrates the sliding holder 20 in the X1-X2 direction, and communicates with a holding recess 24 formed inside the sliding holder 20.

  As shown in FIGS. 3 and 4, the holding recess 24 is formed inside the sliding holder 20 and opens to the back side (X2 side). A back surface 25 facing the X2 side of the sliding holder 20 has a frame shape surrounding the periphery of the opening of the holding recess 24. A portion of the back surface 25 located on the short side on the Y1 side functions as the first support portion 25a, and a portion located on the short side on the Y2 side functions as the second support portion 25b. And the part located in the long side of Z1 side is the side support part 25c, and the part located in the long side of Z2 side is the side support part 25d.

  Positioning protrusions 26a and 26a projecting in the X2 direction are integrally formed on the edge portion on the Z1 side and the edge portion on the Z2 side of the first support portion 25a, respectively, and on the Z1 side of the second support portion 25b. Positioning projections 26b and 26b projecting in the X2 direction are integrally formed on the edge and the edge on the Z2 side, respectively.

  As shown in FIGS. 3 and 5, in the holding recess 24 of the sliding holder 20, first positioning portions 27 a and 27 a formed on the Y1 side on the back portions of the pair of rail surfaces 21 and 21, and Second positioning portions 27b and 27b formed on the Y2 side are provided. As shown in FIG. 5, the pair of first positioning portions 27a and 27a provided on the Y1 side and the pair of second positioning portions 27b and 27b provided on the Y2 side are parallel to the YZ plane. Located on H. The plane H is parallel to the rail surfaces 21 and 21.

  As shown in FIG. 5, the front inner surface 28a located on the Y1 side in the holding recess 24 is the back surface of the receding surface 22 located on the Y1 side, and the front inner surface 28b located on the Y2 side is located on the Y2 side. It is the back surface of the said receding surface 22 located. The front inner surfaces 28a and 28b are formed on the X1 side with respect to the positioning plane H. The front inner surface 28a on the Y1 side is an inclined curved surface or inclined plane that moves in the X1 direction as it goes in the Y2 direction, and the front inner surface 28b on the Y2 side is an inclined curved surface that moves in the X2 direction as it goes in the Y1 direction. Or it is an inclined plane.

  As shown in FIG. 5, inside the holding recess 24, a press-fit surface 29a is formed on the inner surface on the Y1 side, and a press-fit surface 29b is formed on the inner surface on the Y2 side. The interval between the press-fitting surface 29a and the press-fitting surface 29b in the Y1-Y2 direction is the same as or slightly shorter than the length of the magnet 30 in the Y1-Y2 direction. The magnet 30 and the sliding holder 20 are positioned by being lightly press-fitted into the 24.

  The magnet 30 is a magnet in which magnetic powder such as Nd—Fe—B is sintered, or a magnet in which the magnetic powder and a small amount of synthetic resin are sintered, and the surface thereof is coated with an epoxy resin. used. As described above, the magnet 30 has a rectangular shape that can be press-fitted into the holding recess 24 of the sliding holder 20. As shown in FIGS. 1 and 4, the magnet 30 is magnetized such that the upper end surface 31 facing the Y1 side and the lower end surface 32 facing the Y2 side are opposite to each other. In the illustrated embodiment, the upper end surface 31 is magnetized with an N pole and the lower end surface 32 is magnetized with an S pole.

  As shown in FIG. 4, the surface facing the X <b> 1 side of the magnet 30 is a facing surface 33. The facing surface 33 is formed such that the width dimension W2 in the Z1-Z2 direction is the same as or slightly smaller than the width dimension W1 of the opening 23 formed in the sliding holder 20. As shown in FIGS. 1 and 4 and as indicated by a broken line in FIG. 5, the opposing surface 33 of the magnet 30 has a central region including the central portion 33 c rather than the upper end portion 33 a and the lower end portion 33 b in the X1 direction. It is a shape that protrudes to. That is, the facing surface 33 has a curvature only in the Y1-Y2 direction, does not have a curvature in the Z1-Z2 direction, and is a cylindrical curved surface. As shown in FIG. 5, when the center line extending in the X direction by dividing the magnet 30 into two in the Y1-Y2 direction is defined as Ox, the central portion 33c located on the center line Ox in the facing surface 33 is furthest toward the X1 side. It protrudes.

  The magnet 30 has a symmetrical shape on the left and right with a center line Oy divided in the Z1-Z2 direction and extending in the Y direction. At a position retreating to the X2 side with respect to the facing surface 33, a collar part 34 is formed on the side part on the Z1 side, and a collar part 34 is also formed on the side part on the Z2 side. The surfaces facing the X1 side are the contact portions 34a, 34a. The contact portions 34a and 34a are planes parallel to the YZ plane.

  As shown in FIG. 1, the magnet 30 is mounted in the holding recess 24 from the back of the sliding holder 20 with the facing surface 33 facing the X1 side. The upper end surface 31 and the lower end surface 32 of the magnet 30 are press-fitted into the press-fitting surface 29a and the press-fitting surface 29b of the holding recess 24 so that the magnet 30 is positioned and held by the sliding holder 20 so as not to move in the Y direction. Is done.

  Further, the contact portions 34a and 34a formed on the flange portions 34 and 34 of the magnet 30 are equally contacted with the first positioning portions 27a and 27a and the second positioning portions 27b and 27b in the holding recess 24. Thus, the relative position of the magnet 30 with respect to the sliding holder 20 in the X1 direction is determined. Therefore, the facing surface 33 facing the X1 side of the magnet 30 is opposed to the front inner surfaces 28a and 28b in the sliding holder 20 via a small gap.

  The opposing surface 33 of the magnet 30 has a projecting curved surface shape with the central portion 33c protruding in the X1 direction, and includes the central portion 33c of the opposing surface 33 with the magnet 30 positioned and held in the holding recess 24. The central region enters the inside of the opening 23 of the sliding holder 20. Therefore, the space | interval of the X1-X2 direction of the center part 33c of the opposing surface 33 of the magnet 30 and the rail surfaces 21 and 21 can be shortened very much. As shown in FIG. 1, when the rail surfaces 21 and 21 of the sliding holder 20 are pressed against the guide surface 14 in the cylinder 11 a of the housing 11, the distance between the central portion 33 c of the facing surface 33 and the guide surface 14. δ can be made extremely short as long as they do not hit each other, and the magnetic flux density of the leakage magnetic field applied from the magnet 30 to the magnetic detector 16 can be increased.

  Moreover, since it is not necessary to provide the thin part which covers the center part 33c of the opposing surface 33 of the magnet 30 in the front side (X1 side) of the sliding holder 20, manufacture of the sliding holder 20 is easy.

  In the sliding holder 20 of the embodiment, the receding surfaces 22 and 22 and the front inner surfaces 28a and 28b on the back side thereof are provided at the upper and lower portions of the opening 23, but the receding surfaces 22 and 22 are removed. All the regions sandwiched between the rail surface 21 and the rail surface 21 may be openings 23.

  The leaf spring 40 is made of a stainless steel plate for springs, which is a nonmagnetic material. As shown in FIGS. 1, 2, 3, and 5, the leaf spring 40 has a mounting piece 41 directed to the X2 side. The attachment piece 41 is substantially flat. The leaf spring 40 is formed by forming a first bent portion 42 in a U shape on the Y2 side of the mounting piece 41 and folding back the intermediate piece 43. The intermediate piece 43 is substantially flat and extends in the Y1 direction. A second bent portion 44 is formed in a U shape on the Y1 side of the intermediate piece 43, and a pressing piece 45 is folded back. The pressing piece 45 is substantially flat and extends in the Y2 direction.

  The pressing piece 45 of the leaf spring 40 has a pair of support holes 48a and 48a opened at the end on the Y1 side in the Z1-Z2 direction, and spaced apart in the Z1-Z2 direction on the Y2 side. A pair of support holes 48b and 48b are opened. Further, the pressing piece 45 is formed with an elongated notch 45a at the center, and a tongue-shaped auxiliary pressing piece 49 extending integrally from the pressing piece 45 to the Y2 side is formed in the notch 45a. . As shown in FIGS. 3 and 5, the auxiliary pressing piece 49 is deformed so as to slightly protrude from the pressing piece 45 toward the X1 side.

  As shown in FIG. 2, after the magnet 30 is mounted in the holding recess 24 of the sliding holder 20, the positioning projections 26 a and 26 a formed on the back portion of the sliding holder 20 have support holes 48 a that open to the pressing piece 45. , 48a, and positioning protrusions 26b, 26b are inserted into the support holes 48b, 48b. Then, the positioning protrusions 26a, 26a, 26b, 26b protruding from the pressing piece 45 of the leaf spring 40 in the X2 direction are melted, crushed and fixed by caulking.

  By the caulking and fixing, the pressing piece 45 and the back surface 25 of the sliding holder 20 are fixed to each other, and a component assembly in which the sliding holder 20, the magnet 30, and the leaf spring 40 are integrated is completed. In this component assembly, the auxiliary pressing piece 49 formed on the pressing piece 45 directly urges the back surface 35 of the magnet 30 in the X1 direction. With this urging force, the contact portions 34a and 34a of the magnet 30 move. The magnet 30 is pressed against the positioning portions 27a, 27a and 27b, 27b of the sliding holder 20 and is held in the sliding holder 20 so as not to rattle in the X1-X2 direction.

  As shown in FIGS. 2 and 3, the attachment piece 41 of the leaf spring 40 is formed with a holding piece 46 on the Y2 side and a holding piece 47 on the Y1 side. One clamping piece 46 is bent at a right angle in the X1 direction, and the other clamping piece 47 is bent in a U shape and can be elastically deformed in the Y1 direction.

  As shown in FIG. 1, attachment surfaces 12c and 12d facing the X1 side are formed on the moving portion 12b. The mounting surface 12c and the mounting surface 12d are formed with an interval in the Y1-Y2 direction, and the mounting surface 12c and the mounting surface 12d are located on the same plane parallel to the YZ plane. And the clamping protrusion 12e which protrudes to a X1 direction is integrally formed between the attachment surface 12c and the attachment surface 12d.

  As shown in FIG. 2, after the leaf spring 40 is attached to the sliding holder 20, as shown in FIG. 1, the attachment piece 41 of the leaf spring 40 is brought into close contact with the attachment surfaces 12c and 12d of the moving portion 12b. At this time, the clamping protrusion 12e is clamped from the Y1-Y2 direction by the clamping piece 46 and the clamping piece 47. Since the sandwiching piece 47 can be elastically deformed, the sandwiching protrusion 12e is securely sandwiched between the sandwiching piece 46 and the sandwiching piece 47 without causing rattling in the Y1-Y2 direction. The leaf spring 40 is positioned in the X1-X2 direction with respect to the moving part 12b by the attachment piece 41 being in close contact with the attachment surfaces 12c, 12d, and the sandwiching protrusions 12e are sandwiched by the sandwiching pieces 46, 47, Positioned in the Y1-Y2 direction. Further, although not shown, the moving portion 12b is provided with a positioning mechanism for positioning the attachment piece 41 of the leaf spring 40 in the Z1-Z2 direction.

  After the sliding holder 20 and the leaf spring 40 are attached to the moving part 12b as described above, the moving part 12b and the shaft part 12a are mounted in the cylinder 11a of the housing 11 shown in FIG. Stoppers 51, 51 facing the back portion of the pressing piece 45 of the leaf spring 40 with a slight gap are integrally formed on the moving portion 12 d so as to protrude in the Y1-Y2 direction. Therefore, even when the pressing piece 45 of the leaf spring 40 is pushed in the X2 direction when the moving part 12d is assembled in the cylinder 11a, the pushing piece 45 hits the stoppers 51 and 51, and an excessive deformation stress is applied to the leaf spring 40. It can be prevented from acting.

  As shown in FIG. 1, in a state where the movement detecting device 10 is assembled, the leaf spring 40 is slightly compressed in the X2 direction, and the elastic holder force of the leaf spring 40 in the X1 direction causes the sliding holder The 20 rail surfaces 21 and 21 are pressed against the guide surface 14 in the cylinder 11a.

  When the pressing piece 45 of the leaf spring 40 is pressed in the X2 direction and is compressed and deformed, as shown in FIG. 5, the elastic force that repels the intermediate piece 43 clockwise with the first bent portion 42 as a fulcrum. A moment M1 is generated, and an elastic moment M2 is generated to try to repel the pressing piece 45 counterclockwise with the second bent portion 44 as a fulcrum. Since the opposing elastic moments M1 and M2 act on the sliding holder 20, the sliding holder 20 is pressed against the guide surface 14 without a large pressure bias. Therefore, the sliding holder 20 smoothly slides on the guide surface 14 in both directions when the sliding holder 20 slides on the guide surface 14 in the Y1 direction and when sliding on the guide surface 14 in the Y2 direction. And the phenomenon that the sliding holder 20 tilts and rattles is less likely to occur.

  In the assembled state shown in FIG. 1, the attachment piece 41 and the pressing piece 45 of the leaf spring 40 are parallel to each other. They are also parallel to the guide surface 14 in the cylinder 11a. Since the pressing piece 45 and the mounting piece 41 are parallel to the guide surface 14, the X1 direction acting on the sliding holder 20 when the sliding holder 20 slides in the Y1 direction and when sliding in the Y2 direction. It can be avoided that the intensity distribution of the pressing force is greatly biased in the Y direction.

  Further, the first support portion 25a on the Y1 side of the back surface of the sliding holder 20 is located on the X1 side in the vicinity of the second bent portion 44 of the leaf spring 40, and the second supporting portion on the Y2 side of the sliding holder 20 is located. The support portion 25b faces the X2 side in the vicinity of the first bent portion 42 of the leaf spring 40. Therefore, the restoring elastic force of the first bent portion 42 of the leaf spring 40 acts in the X1 direction at or near the second support portion 25b of the back portion of the sliding holder 20, and the second bent portion 44 is restored. The elastic force acts in the X1 direction at or near the first support portion 25a of the sliding holder 20. Since the load in the X1 direction acts on the first support portion 25a and the second support portion 25b that are separated in the Y1-Y2 direction of the slide holder 20, the slide holder 20 is applied to the guide surface 14. It becomes easy to slide in both the Y1 direction and the Y2 direction without tilting along.

  Moreover, the sliding holder 20 can also reduce the frictional resistance force at the time of sliding, when a pair of rail surfaces 21 and 21 extended in a Y1-Y2 direction slide on the guide surface 14. FIG.

  As shown in FIG. 4, the magnet 30 has an upper end surface 31 and a lower end surface 32 that are magnetized with opposite magnetic poles. Therefore, the vector component in the X1 direction of the magnetic flux φ is large in front of the upper end portion 33a of the opposing surface 33, the vector component in the X2 direction of the magnetic flux φ is large in front of the lower end portion 33b, and the X1 of the magnetic flux φ is in the central portion 33c. The vector component in the direction or X2 direction is minimized. When the magnet 30 moves in the Y1-Y2 direction together with the moving unit 12b, the magnetic detector 16 detects a change in the magnitude of the vector component in the X1 direction and the vector component in the X2 direction of the magnetic flux φ, and the moving unit 12b The moving position of the magnet 30 is measured.

  In such a detection method, it is necessary for the magnet 30 to move stably and smoothly without tilting in the Y1-Y2 direction while always maintaining the same distance as the guide surface 14. In the movement detection device 10 according to the embodiment of the present invention, by using the leaf spring 40 having the above structure, the sliding holder 20 can slide on the guide surface 14 stably and is provided on the leaf spring 40. By the auxiliary pressing piece 49, the magnet 30 is pressed and positioned in the X1 direction in the sliding holder 20. Therefore, when the sliding holder 20 slides in the Y1-Y2 direction, the facing distance between the facing surface 33 of the magnet 30 and the magnetic detector 16 can always be realized as designed.

  Further, when the opposing surface 33 of the magnet 30 is formed into a protruding curved surface shape in which the central portion 33c protrudes most in the X1 direction, the magnetic detector 16 with respect to the moving distance when the magnet 30 moves linearly in the Y1-Y2 direction. The change in the magnetic flux density in the X1-X2 direction acting on the curve shows a change close to a linear function. Therefore, the movement amount of the moving part 12b, that is, the opening degree of the control valve 1 can be detected linearly by the detection output of the magnetic detector 16.

  Even if the facing surface 33 of the magnet 30 has a projecting curved surface shape, the opening 23 is formed in the sliding holder 20 at a portion facing the central region including the central portion 33c. The central portion 33c can be brought close to the facing surface 14 without hitting the guide surface 14. Therefore, it is possible to increase the detection sensitivity of the leakage magnetic field by the magnetic detector 16.

Sectional drawing which shows the movement detection apparatus of embodiment of this invention, The perspective view which shows the state by which the sliding holder, the magnet, and the leaf | plate spring were integrated from the back part side, An exploded perspective view showing the sliding holder, the magnet and the leaf spring from the back side, An exploded perspective view showing the sliding holder and the magnet from the front side, Cross section of sliding holder and leaf spring,

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control valve 10 Movement detection apparatus 11 Housing 12b which is a fixed part Moving part 12e, 12d Mounting surface 14 Guide surface 16 Magnetic detector 20 Slide holder 21 Rail surface 23 Opening part 24 Holding recessed part 25a 1st support part 25b 2nd Support portion 26a first positioning projection 26b second positioning projection 27a first positioning portion 27b first positioning portion 30 magnet 33 facing surface 34a abutting portion 40 leaf spring 41 mounting piece 42 first bent portion 43 Intermediate piece 44 Second bent portion 45 Pressing piece 49 Auxiliary pressing piece

Claims (5)

A moving part that linearly reciprocates along a guide part provided in the fixed part, a magnet that moves together with the moving part, and a magnetic sensor that is installed in the fixed part and detects a leakage magnetic field from the magnet In a movement detection device having a device,
The opposing surface of the magnet that faces the magnetic detector has a shape in which an intermediate region protrudes toward the side where the magnetic detector is disposed, rather than both end portions of the moving portion that are directed in the moving direction.
A movement detection apparatus comprising: a holder that holds the magnet and moves together with the moving unit, and the holder has an opening formed at least in a portion facing the central region of the facing surface.   2. The movement detection device according to claim 1, wherein the facing surface of the magnet is a protruding curved surface in which the intermediate region protrudes toward the side where the magnetic detector is disposed from the both end portions.   The holder has a holding recess that opens at a back portion that is a side opposite to the side to which the facing surface faces, and the magnet is inserted into the holding recess from the back portion, and the magnet is inserted into the holding recess. The movement detecting device according to claim 1, wherein the movement detecting device is fixed so as not to move in a moving direction of the moving unit.   The magnet is provided with an abutting portion at a position retracted from the facing surface, the holder is provided with a positioning portion in a region other than the opening, and the abutting portion serves as the positioning portion. The movement detection device according to claim 1, wherein the movement detection device is supported and the magnet is positioned in the holder.   A leaf spring is provided between the moving part and the holder, and the holder is pressed toward the side where the magnetic detector is disposed by the leaf spring, and is provided on the leaf spring. The movement detection device according to claim 4, wherein the magnet is directly pressed by an auxiliary pressing piece, and the contact portion is elastically pressed by the positioning portion.

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