JP2014149180A - Torque sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the detection accuracy of a torque sensor.SOLUTION: A torque sensor is equipped with: a magnetic detector 48 for detecting magnetic flux density guided from a magnetism generating portion 22 to a fixed magnetic circuit portion 31 through a rotational magnetic circuit portion 25 with torsional deformation of a torsion bar 21; and a support member 50 for supporting the magnetic detector 48 on a circuit substrate 47. The support member 50 has: a body portion 51 having a positioning surface 51a which surface-contacts with a surface 47a of the circuit substrate 47; a positioning portion 54 for positioning the body portion 51 to the circuit substrate 47; and a pair of holding portions 52 for holding the magnetic detector 48. The magnetic detector 48 surface-contacts with the body portion 51 with a back surface 48b, and surface-contacts with inner surfaces of the pair of the holding portions 52 with both side surfaces 48a, thereby being held by the support member 50.

Description

  The present invention relates to a torque sensor that detects torque acting on a torsion bar.

  As a torque sensor provided in a vehicle steering apparatus, a non-contact type sensor that detects a steering torque acting on a steering shaft by a magnetic force is known.

  In Patent Document 1, a cylindrical magnet that rotates integrally with a first shaft, a set of two yoke rings that rotate together with a second shaft, and a set of two magnetism collecting rings that separately surround the outside of the yoke ring. And a magnetic sensor disposed between the opposing surfaces of the magnetic flux collecting protrusions projecting outward on the outer circumference of each magnetic flux collecting ring, and the first is based on the magnetic flux density between the magnetic flux collecting protrusions detected by the magnetic sensor. A torque detector that detects torque applied to the first shaft and the second shaft is disclosed.

  In Patent Document 1, a magnetic sensor supported by a circuit board is inserted into an air gap between opposing surfaces of magnetic collecting protrusions of two magnetic collecting rings along the protruding direction of the magnetic collecting protrusions and positioned. Is disclosed.

JP 2005-345284 A

  The magnetic sensor is mounted on the circuit board by soldering and is disposed in the air gap between the opposing surfaces of the magnetic flux collecting projections.

  Here, if the magnetic sensor is mounted on the circuit board at an angle from a desired angle due to mounting errors when soldering the magnetic sensor to the circuit board, the magnetic sensor is disposed at an angle in the air gap. End up. In that case, since the incident angle of the induced magnetic flux with respect to the magnetic sensor deviates from the ideal angle, the magnetic sensor's magnetic flux density detection sensitivity decreases, and the torque sensor detection accuracy decreases.

  The present invention has been made in view of the above-described problems, and an object thereof is to increase the detection accuracy of a torque sensor.

  The present invention is a torque sensor for detecting a torque acting on a torsion bar that connects a first shaft and a second shaft that are rotatably supported in a housing, and a magnetism generator that rotates together with the first shaft; A rotating magnetic circuit portion that rotates together with the second shaft, a fixed magnetic circuit portion fixed to the housing, and a magnetic gap provided in the fixed magnetic circuit portion, and accompanying torsional deformation of the torsion bar A magnetic detector for detecting a magnetic flux density guided to the fixed magnetic circuit section from the magnetism generating section through the rotating magnetic circuit section; and a support member for supporting the magnetic detector on a circuit board. The member is formed with a main body having a positioning surface in surface contact with the surface of the circuit board, and penetrates through the main body, and the magnetic detector A through hole through which a lead wire for electrically connecting the circuit board is inserted; a positioning part formed in the main body part for positioning the main body part with respect to the circuit board; and the magnetic detector from the main body part. A pair of holding portions that extend along both side portions and hold the magnetic detector, and the magnetic detector has a back surface that makes surface contact with the main body portion, and both side surfaces of the pair of holding portions. The support member is held in surface contact with the inner surface.

  According to the present invention, since the magnetic detector is positioned and supported on the circuit board via the support member, the magnetic detector is prevented from being mounted on the circuit board at a desired angle. Therefore, since the magnetic detector is prevented from being inclined and arranged in the magnetic gap, the detection accuracy of the torque sensor can be increased.

1 is a longitudinal sectional view of an electric power steering apparatus to which a torque sensor according to an embodiment of the present invention is applied. It is a perspective view of a ring magnet, a rotating magnetic circuit part, a fixed magnetic circuit part, and a magnetic sensor. It is a bottom view of a magnetism generation part. It is a perspective view of a rotating magnetic circuit part. It is a perspective view of a support member. It is a top view of a support member. It is a disassembled perspective view of a magnetic sensor, a support member, and a circuit board. It is a perspective view in the state where a magnetic sensor was held by a support member. It is a perspective view of a substrate assembly. It is a disassembled perspective view of a board | substrate assembly and a sensor holder. It is a perspective view of a sensor holder. It is a perspective view which shows the positional relationship of a 1st, 2nd magnetism collection yoke and a board | substrate assembly.

  Hereinafter, a torque sensor 100 according to an embodiment of the present invention will be described with reference to the drawings.

  First, the electric power steering apparatus 1 to which the torque sensor 100 is applied will be described with reference to FIG.

  In the electric power steering apparatus 1, the steering shaft 10 and the output shaft 12 rotate in conjunction with the steering wheel, and the wheels are moved by moving the rack shaft meshing with the pinion provided at the lower end of the output shaft 12 in the axial direction. To steer.

  The electric power steering apparatus 1 includes a worm wheel coupled to the output shaft 12, a worm meshing with the worm wheel, and an electric motor that rotationally drives the worm as an assist mechanism that assists in providing steering torque. Prepare. The electric power steering device 1 applies steering assist torque to the output shaft 12 by an electric motor.

  The steering shaft 10 has an input shaft 11 as a first shaft and a torsion bar 21 connected to the input shaft 11. The input shaft 11 is rotatably supported by the housing 30 via a rolling bearing 37. The output shaft 12 as the second shaft is rotatably supported by the housing 41 via the rolling bearing 38. A sliding bearing 39 is interposed between the lower end side of the input shaft 11 and the upper end side of the output shaft 12. The input shaft 11 and the output shaft 12 are supported by the housings 30 and 41 so as to be rotatable on the same axis.

  The input shaft 11 is formed in a cylindrical shape, and a torsion bar 21 is accommodated coaxially inside the input shaft 11. The upper end portion of the torsion bar 21 is connected to the upper end portion of the input shaft 11 via a pin 28. A lower end portion of the torsion bar 21 protrudes from a lower end opening portion of the input shaft 11 and is connected to the output shaft 12 via a serration 29. The torsion bar 21 transmits the steering torque input to the input shaft 11 to the output shaft 12 via the steering wheel, and is torsionally deformed around the rotation axis O in accordance with the steering torque.

  The electric power steering apparatus 1 is provided with a non-contact torque sensor 100 that detects a steering torque acting on a torsion bar 21 that connects the input shaft 11 and the output shaft 12. Hereinafter, the torque sensor 100 will be described.

  As shown in FIGS. 1 and 2, the torque sensor 100 includes a magnetic generator 22 that is fixed to the input shaft 11 and rotates with the input shaft 11, and a rotating magnetic circuit unit 25 that is fixed to the output shaft 12 and rotates with the output shaft 12. And a magnetic detection unit that detects a magnetic flux density guided from the magnetism generating unit 22 to the fixed magnetic circuit unit 31 through the rotating magnetic circuit unit 25 as the torsional deformation of the torsion bar 21 is performed. And a magnetic sensor 48 as a container. The torque sensor 100 detects the steering torque acting on the torsion bar 21 based on the output of the magnetic sensor 48.

  Instead of the above configuration, the magnetism generating unit 22 may be fixed to the output shaft 12 so as to rotate with the output shaft 12, and the rotating magnetic circuit unit 25 may be fixed to the input shaft 11 so as to rotate with the input shaft 11. .

  As shown in FIGS. 1 and 3, the magnetism generator 22 includes an annular back yoke 24 that is press-fitted into the input shaft 11, and an annular ring magnet 23 that is coupled to the lower end surface of the back yoke 24.

  The ring magnet 23 is an annular permanent magnet that generates magnetism in the direction of the rotation axis O of the input shaft 11. The ring magnet 23 is a multipolar magnet formed by magnetizing a hard magnetic material in the direction of the rotation axis O, and has 12 magnetic poles formed with an equal width in the circumferential direction. That is, on the upper end surface and the lower end surface of the ring magnet 23, six N poles and six S poles are alternately arranged in the circumferential direction. The number of magnetic poles formed on the end face of the ring magnet 23 is arbitrarily set within a range of 2 or more.

  The back yoke 24 has an upper magnetic pole surface, which is an upper end surface of the ring magnet 23, fixed to the lower end surface thereof with an adhesive. Further, since the back yoke 24 is formed of a soft magnetic material, it is magnetized by the magnetic field exerted by the ring magnet 23 and is attracted to the ring magnet 23. Thus, the ring magnet 23 and the back yoke 24 are coupled by the adhesive force and magnetic force of the adhesive. The back yoke 24 has a function as a connecting member for connecting the ring magnet 23 to the input shaft 11 and a function as a yoke for connecting the magnetic poles adjacent to the ring magnet 23 to guide the magnetic flux. The magnetic force is concentrated on the lower magnetic pole surface which is the end face.

  As shown in FIGS. 1, 2, and 4, the rotating magnetic circuit unit 25 includes a first soft magnetic ring 26 and a second soft magnetic ring 27 to which a magnetic flux generated from the ring magnet 23 of the magnetism generating unit 22 is guided. The mounting member 70 is attached to the output shaft 12, and the mold resin 71 fixes the first soft magnetic ring 26 and the second soft magnetic ring 27 to the mounting member 70.

  The first soft magnetic ring 26 includes an annular first magnetic path ring portion 26C, six first magnetic path column portions 26B protruding downward from the first magnetic path ring portion 26C, and each first magnetic path column portion. A first magnetic path front end portion 26A that refracts inward from the lower end of 26B and faces the lower end surface of the ring magnet 23. The second soft magnetic ring 27 includes an annular second magnetic path ring portion 27C, six second magnetic path column portions 27B protruding upward from the second magnetic path ring portion 27C, and each second magnetic path column portion. The second magnetic path tip portion 27A is refracted inward from the upper end of 27B and faces the lower end surface of the ring magnet 23.

  The first soft magnetic ring 26 and the second soft magnetic ring 27 are each formed by pressing. The first soft magnetic ring 26 and the second soft magnetic ring 27 are not limited to pressing, and may be formed by casting, sintering, or the like.

  The first magnetic path tip portion 26A and the second magnetic path tip portion 27A are formed in a flat plate shape. The first magnetic path tip end portion 26A and the second magnetic path tip end portion 27A are arranged on the same plane orthogonal to the rotation axis O of the torsion bar 21 alternately at equal intervals in the circumferential direction around the rotation axis O. The

  Further, the first magnetic path tip portion 26A and the second magnetic path tip portion 27A are in a neutral state where no torque acts on the torsion bar 21, and the respective center lines extending in the radial direction of the torsion bar 21 are the ring magnets 23. It arrange | positions so that the boundary of N pole and S pole may be pointed out.

  The first magnetic path column portion 26B and the second magnetic path column portion 27B are each formed in a flat plate shape and extend in the direction of the rotation axis O. The first magnetic path column portion 26 </ b> B is disposed so as to surround the outer peripheral surface of the ring magnet 23 with a predetermined gap. The first magnetic path column part 26 </ b> B is provided so as not to short-circuit the magnetic flux of the ring magnet 23. The second magnetic path column portion 27B extends along the rotation axis O in the direction opposite to the first magnetic path column portion 26B.

  The first magnetic path ring portion 26 </ b> C and the second magnetic path ring portion 27 </ b> C are arranged on a plane orthogonal to the rotation axis O, and are formed in an annular shape in which the entire circumference is connected. The first magnetic path ring portion 26 </ b> C and the second magnetic path ring portion 27 </ b> C are not limited to this shape, and may be a C shape in which a slit is partially formed.

  The first magnetic path ring portion 26 </ b> C is disposed above the lower end surface of the ring magnet 23, and the second magnetic path ring portion 27 </ b> C is disposed below the ring magnet 23. That is, the ring magnet 23 is disposed between the first magnetic path ring portion 26C and the second magnetic path ring portion 27C in the rotation axis O direction.

  As shown in FIGS. 1 and 2, the fixed magnetic circuit portion 31 includes a first magnetic flux collecting ring 32 provided along the outer periphery of the first magnetic path ring portion 26 </ b> C of the first soft magnetic ring 26, and a second soft magnetic ring portion 26. A second magnetism collecting ring 33 provided along the outer periphery of the second magnetic path ring portion 27C of the magnetic ring 27, a first magnetism collecting yoke 34 connected to the first magnetism collecting ring 32, and a second magnetism collecting ring. And a second magnetism collecting yoke 35 connected to 33.

  The first magnetism collecting ring 32 and the second magnetism collecting ring 33 have a C shape in which slits are partially formed, and are caulked and fixed to the inner peripheral surface of the housing 30. The inner peripheral surface of the first magnetic flux collecting ring 32 faces the first magnetic path ring portion 26C of the first soft magnetic ring 26, and the inner peripheral surface of the second magnetic flux collecting ring 33 is the second magnetic field of the second soft magnetic ring 27. It faces the road ring portion 27C.

  As described above, the first magnetism collecting ring 32 and the second magnetism collecting ring 33 are arranged on the outer periphery of the rotating magnetic circuit unit 25, and alleviate the influence of rotational shake and eccentricity of the rotating magnetic circuit unit 25, thereby reducing the magnetic sensor 48 side. Has the function of guiding the magnetic flux to the

  The first magnetic flux collecting yoke 34 is formed in a block shape having an arc-shaped inner circumferential surface 34 a that abuts the outer circumferential surface of the first magnetic flux collecting ring 32, and the second magnetic flux collecting yoke 35 is an outer circumferential surface of the second magnetic flux collecting ring 33. Is formed in a block shape having an arcuate inner peripheral surface 35a that abuts on the inner surface.

  The first magnetic flux collecting yoke 34 has a pair of magnetic flux collecting projections 34b extending in the direction of the rotational axis O, and the second magnetic flux collecting yoke 35 has a pair of magnetic flux collecting convex portions 35b extending in the direction of the rotational axis O. . The pair of magnetic flux collecting convex portions 34b of the first magnetic flux collecting yoke 34 and the pair of magnetic flux collecting convex portions 35b of the second magnetic flux collecting yoke 35 face each other with a magnetic gap that is a predetermined gap. That is, a pair of magnetic gaps arranged in the circumferential direction is formed between the first magnetism collecting yoke 34 and the second magnetism collecting yoke 35. A magnetic sensor 48 is disposed in each magnetic gap.

  The first magnetism collecting yoke 34 and the second magnetism collecting yoke 35 have a function of collecting the magnetic flux from the rotating magnetic circuit unit 25 to the magnetic sensor 48 via the first magnetism collecting ring 32 and the second magnetism collecting ring 33.

  A magnetic sensor 48 for detecting magnetism is supported on the circuit board 47 via a support member 50 (see FIG. 5). The circuit board 47 includes a circuit that processes the output voltage of the magnetic sensor 48. The first magnetism collecting yoke 34, the second magnetism collecting yoke 35, the magnetic sensor 48, and the circuit board 47 are fixed to a sensor holder 40 made of resin. In addition, illustration of the support member 50 is abbreviate | omitted in FIG.

  A hall element is used for the magnetic sensor 48, and the hall element outputs a voltage corresponding to the density of magnetic flux passing therethrough as a signal. The magnetic sensor 48 outputs a voltage according to the magnitude and direction of the magnetic field of the magnetic gap through the circuit board 47 and the terminal 44. The terminal 44 is connected to a controller that controls the driving of the electric power steering apparatus 1 through a wiring connected to the sensor holder 40.

  A pair of magnetic sensors 48 are provided corresponding to a pair of magnetic gaps arranged in the circumferential direction formed between the first magnetism collecting yoke 34 and the second magnetism collecting yoke 35, one being a main system and the other being a sub system. Become. For control of the electric motor of the electric power steering apparatus 1, an output voltage output from the magnetic sensor 48 of the main system is used. The output voltage output from the magnetic sensor 48 of the sub system is used for diagnosing abnormality of the torque sensor 100 by the controller. Specifically, the controller compares the steering torque detected in the main system and the steering torque detected in the sub system, and determines that the difference is greater than or equal to a predetermined tolerance. It is determined that an abnormality has occurred in the torque sensor 100.

  Next, a method for detecting the steering torque acting on the torsion bar 21 by the torque sensor 100 will be described.

  In a neutral state in which no torque acts on the torsion bar 21, the first magnetic path tip end portion 26 A of the first soft magnetic ring 26 and the second magnetic path tip end portion 27 A of the second soft magnetic ring 27 are respectively N of the ring magnet 23. Opposite the pole and the S pole with the same area and magnetically short-circuit both. Therefore, the magnetic flux is not guided to the rotating magnetic circuit unit 25 and the fixed magnetic circuit unit 31.

  When a torque in a specific direction acts on the torsion bar 21 by the driver's operation of the steering wheel, the torsion bar 21 is twisted and deformed according to the direction of the torque. When the torsion bar 21 is torsionally deformed, the first magnetic path tip 26A faces the N pole with a larger area than the S pole, while the second magnetic path tip 27A has a larger area at the S pole than the N pole. Confront. The magnetic flux from the ring magnet 23 is guided to the fixed magnetic circuit unit 31 through the rotating magnetic circuit unit 25. Specifically, the first soft magnetic ring 26, the first magnetic flux collecting ring 32, the first magnetic flux collecting yoke 34, the second magnetic flux collecting yoke 35, the second magnetic flux collecting ring 33, and the second soft magnetic ring 27 are arranged from the N pole. This is a route that goes to the south pole. The magnetic sensor 48 disposed in the magnetic gap between the first magnetic collecting yoke 34 and the second magnetic collecting yoke 35 outputs a voltage value corresponding to the magnitude and direction of the magnetic flux.

  On the other hand, when a torque in the direction opposite to the above acts on the torsion bar 21 by the operation of the steering wheel by the driver, the torsion bar 21 is twisted and deformed in the reverse direction according to the direction of the torque. When the torsion bar 21 is torsionally deformed, the first magnetic path tip 26A opposes with a larger area than the N pole with the S pole, while the second magnetic path tip 27A has a larger area with the N pole than the S pole. Confront. The magnetic flux from the ring magnet 23 is guided to the fixed magnetic circuit unit 31 through the rotating magnetic circuit unit 25, but has a path opposite to the above. Specifically, the second soft magnetic ring 27, the second magnetic flux collecting ring 33, the second magnetic flux collecting yoke 35, the first magnetic flux collecting yoke 34, the first magnetic flux collecting ring 32, and the first soft magnetic ring 26 are arranged from the N pole. This is a route that goes to the south pole. The magnetic sensor 48 disposed in the magnetic gap between the first magnetic collecting yoke 34 and the second magnetic collecting yoke 35 outputs a voltage value corresponding to the magnitude and direction of the magnetic flux.

  The larger the difference in the area where the first magnetic path tip 26A faces the N and S poles of the ring magnet 23 and the larger the area difference where the second magnetic path tip 27A faces the N and S poles of the ring magnet 23, the greater the magnetism. The magnetic flux induced in the gap increases and the output voltage of the magnetic sensor 48 also increases. Therefore, the magnetic flux density guided to the magnetic sensor 48 can be increased by increasing the number of magnetic poles of the ring magnet 23.

  Next, the support member 50 for supporting the magnetic sensor 48 on the circuit board 47 will be described in detail with reference to FIGS.

  As shown in FIGS. 5 to 7, the support member 50 includes a main body 51 having a positioning surface 51 a that is in surface contact with the surface 47 a of the circuit board 47, and a holding portion 52 that holds the magnetic sensor 48. The support member 50 is formed of an insulating member, specifically, a resin material.

  The main body 51 has support columns 53 coupled to both sides. A surface facing the circuit board 47 in the support portion 53 is a positioning surface 51a. A positioning surface 51 a is also formed at the center of the main body 51.

  A boss 54 as a positioning portion for positioning the main body 51 with respect to the circuit board 47 is formed on the positioning surface 51 a of the support column 53 by fitting into the positioning hole 47 b formed in the circuit board 47. The positioning surface 51 a regulates the inclination of the main body 51 with respect to the circuit board 47, and the boss 54 defines the position of the main body 51 with respect to the circuit board 47. Therefore, the support member 50 is positioned at a desired position with respect to the circuit board 47 by fitting the boss 54 into the positioning hole 47b of the circuit board 47 with the positioning surface 51a in surface contact with the surface 47a of the circuit board 47. . The support post 53 may be formed integrally with the main body 51.

  A snap fit 55 serving as a locking portion that is locked to a through hole 47 c formed in the circuit board 47 and prevents the support member 50 from falling off from the circuit board 47 is formed on the positioning surface 51 a at the center of the main body 51. It is formed. The snap fit 55 is composed of a pair of locking pieces. When the pair of locking pieces enter the through-hole 47c, the claw portions 55a on the distal end side bend in a direction approaching each other, and after the claw portions 55a pass through the through-hole 47c, the original shape is restored. 55b fits snugly on the inner peripheral surface of the through hole 47c. In this state, since the claw portion 55a is locked to the back surface of the circuit board 47, the support member 50 is prevented from falling off from the circuit board 47.

  On the surface of the main body 51 that faces the circuit board 47, there is a recess 51d that is formed so as to have a space between the positioning surface 51a and the surface 47a of the circuit board 47 with the positioning surface 51a in contact with the circuit board 47. It is formed.

  A pair of holding portions 52 are provided for each magnetic sensor 48, and are formed to extend from the main body portion 51 along both side surfaces 48 a of the magnetic sensor 48. As shown in FIG. 8, the magnetic sensor 48 is configured such that the back surface 48 b is in surface contact with the end surface 51 b on the counter-circuit board side in the main body 51, and both side surfaces 48 a are in surface contact with the inner surfaces 52 a of the pair of holding portions 52. , Positioned and held with respect to the support member 50. The end surface 51 b of the main body 51 and the inner surface 52 a of the holding portion 52 regulate the inclination of the magnetic sensor 48 with respect to the support member 50, and function as positioning surfaces for positioning the magnetic sensor 48 with respect to the support member 50. In the present embodiment, the end surface 51b of the main body 51 is parallel to the positioning surface 51a that makes surface contact with the circuit board 47, and the inner surface 52a of the holding portion 52 is perpendicular to the end surface 51b.

  A claw piece 60 is formed at the tip of the holding portion 52 so as to protrude inward from the inner surface 52 a of the holding portion 52. The claw piece 60 prevents the magnetic sensor 48 from coming off the holding portion 52 by contacting the front surface 48 c of the magnetic sensor 48.

  A lead wire 56 that electrically connects the magnetic sensor 48 and the circuit board 47 is connected to the magnetic sensor 48 (see FIG. 7). The main body 51 is formed with an insertion portion 51c through which the lead wire 56 is inserted. The insertion portion 51c is formed to open to the end surface 51b and to the recess portion 51d. In the present embodiment, the insertion portion 51c is formed as a through-hole penetrating the main body 51, but may be formed in a groove shape.

  When the magnetic sensor 48 is held by the support member 50, the magnetic sensor 48 is inserted between the pair of holding portions 52 in a state where the tip ends of the pair of holding portions 52 are widened in the direction in which the claw pieces 60 are separated from each other. At the same time, the lead wire 56 is inserted into the insertion portion 51c. And after making the back surface 48b of the magnetic sensor 48 contact the end surface 51b of the main-body part 51, a pair of holding | maintenance part 52 is returned and the nail | claw piece 60 is contact | abutted to the front surface 48c of the magnetic sensor 48 (refer FIG. 8). . In this way, the magnetic sensor 48 is held by the support member 50.

  The holding part 52 is formed thin only near the tip where the claw piece 60 is formed. Thereby, the front end side of the holding | maintenance part 52 can be expanded with small force, ensuring the area of the inner surface 52a of the holding | maintenance part 52 which functions as a positioning surface.

  Tapered surfaces 48d are formed on both side surfaces 48a of the magnetic sensor 48, and the magnetic sensor 48 is formed in a trapezoidal cross section. The main body 51 is formed with a protrusion 61 that comes into contact with the tapered surface 48 d when the magnetic sensor 48 is inserted between the pair of holding parts 52. The magnetic sensor 48 is configured such that the lead wire 56 passes through the insertion portion 51 c only when the taper surface 48 d is inserted between the pair of holding portions 52 in a direction in which the taper surface 48 d comes into contact with the protrusion 61. Thus, the protrusion 61 is for preventing the magnetic sensor 48 from being inserted between the pair of holding portions 52 with the front and back sides of the magnetic sensor 48 being reversed in the reverse direction.

  The circuit board 47 is formed with a through hole 47 d through which the lead wire 56 is inserted. In the through hole 47d and the insertion part 51c of the main body 51, the boss 54 is fitted in the positioning hole 47b of the circuit board 47, and the snap fit 55 is locked in the through hole 47c of the circuit board 47 so that the support member 50 is connected to the circuit board 47. It forms so that it may correspond in the state attached to the board | substrate 47. FIG. Therefore, as shown in FIG. 9, when the support member 50 holding the magnetic sensor 48 is attached to the circuit board 47, the lead wire 56 of the magnetic sensor 48 passes through the through hole 47 d of the circuit board 47. .

  As shown in FIG. 9, when the magnetic sensor 48 is supported on the circuit board 47 via the support member 50, the magnetic sensor 48 is attached to the support member 50 by the end surface 51 b of the main body portion 51 and the inner surface 52 a of the holding portion 52. Since the support member 50 is positioned with respect to the circuit board 47 by the positioning surface 51a and the boss 54, the magnetic sensor 48 is positioned and supported by the circuit board 47 via the support member 50. It becomes a state. Thus, by supporting the magnetic sensor 48 on the circuit board 47 through the support member 50, the angle of the magnetic sensor 48 with respect to the circuit board 47 can be set to a desired angle. In the present embodiment, the magnetic sensor 48 is set perpendicular to the circuit board 47.

  In a state where the magnetic sensor 48 is supported by the circuit board 47 via the support member 50, the lead wires 56 are soldered to the circuit board 47. Therefore, the magnetic sensor 48 is prevented from being inclined with respect to the circuit board 47 during soldering. Thereby, the magnetic sensor 48 can be mounted on the circuit board 47 at a desired angle. The magnetic sensor 48 is fixed to the circuit board 47 by soldering, and a board assembly 80 constituted by the magnetic sensor 48, the support member 50, and the circuit board 47 is obtained.

  The snap fit 55 functions to prevent the support member 50 from dropping from the circuit board 47 and to prevent rattling between the boss 54 and the positioning hole 47b during soldering. Thus, the snap fit 55 has a function of temporarily fixing the support member 50 to the circuit board 47 prior to soldering. Further, the claw piece 60 at the tip of the holding portion 52 prevents the magnetic sensor 48 from coming off from the holding portion 52 during soldering.

  Soldering is performed from the back side of the circuit board 47. At the time of soldering, a solder fillet is formed on the back surface of the circuit board 47, and the solder flows into the front surface 47 a side of the circuit board 47 through between the lead wire 56 and the through hole 47 d of the circuit board 47. Since there is a space between the surface 47a of the circuit board 47 and the recess 51d of the main body 51 (see FIG. 9), solder fillets are also formed on the surface 47a of the circuit board 47. Therefore, good conduction between the circuit board 47 and the lead wire 56 is realized.

  Next, assembly of the substrate assembly 80 to the sensor holder 40 will be described with reference to FIGS.

  As shown in FIG. 10, the sensor holder 40 includes a first holder 81 attached to the housing 30 (see FIG. 1) via a bolt fastened to a bolt fastening hole 81a, a first magnetism collecting yoke 34, and a second current collector. And a second holder 82 that supports the magnetic yoke 35.

  The first holder 81 has a cylindrical opening 81 b, four terminals 44 are provided in the opening 81 b, and a substrate receiving groove 85 having an inner peripheral shape corresponding to the outer peripheral shape of the circuit board 47 is formed. It is formed. In the opening 81b, four bosses 83 are provided at substantially 90 degree intervals along the inner peripheral surface of the opening 81b. The terminal 44 may be provided not on the first holder 81 but on the second holder 82.

  The second holder 82 is a circular member having an outer peripheral surface that fits into the inner peripheral surface of the opening 81 b of the first holder 81. The second holder 82 is provided with four boss receiving portions 84 into which the boss 83 of the first holder 81 is inserted.

  A method for assembling the substrate assembly 80 to the sensor holder 40 will be described.

  First, the substrate assembly 80 is accommodated in the substrate accommodation groove 85 of the first holder 81 via an adhesive. In this state, the terminal 44 is inserted through the through hole 47 e formed in the circuit board 47. Then, the terminal 44 is soldered to the circuit board 47. Thereby, the substrate assembly 80 is fixed to the first holder 81.

  Next, as shown in FIG. 11, the second holder 82 of the first holder 81 is fitted so that the four bosses 83 formed on the first holder 81 fit into the boss receiving portions 84 formed on the second holder 82. The first holder 81 and the second holder 82 are assembled by being inserted into the opening 81b. As a result, the relative position between the first holder 81 and the second holder 82 is determined, and the magnetic sensor 48 is located between the magnetism collecting convex portion 34 b of the first magnetism collecting yoke 34 and the magnetism collecting convex portion 35 b of the second magnetism collecting yoke 35. It is arranged in the magnetic gap.

  Finally, the first holder 81 and the second holder 82 are fixed by applying heat to the tip of the boss 83 protruding from the boss receiving portion 84 to deform it.

  Thus, the assembly of the substrate assembly 80 to the sensor holder 40 is completed. The sensor holder 40 is attached to the housing 30 via a bolt fastened to the bolt fastening hole 81a while the cylindrical portion 40a is fitted into the opening 30a (see FIG. 1) of the housing 30.

  Next, the positional relationship between the first and second magnetic flux collecting yokes 34 and 45 and the magnetic sensor 48 in the sensor holder 40 will be described with reference to FIG.

  The board assembly 80 is positioned with respect to the first holder 81 when the circuit board 47 is housed in the board housing groove 85 of the first holder 81. The relative positions of the first holder 81 and the second holder 82 are determined by the four bosses 83. In this state, the magnetic sensor 48 mounted on the circuit board 47 at a desired angle includes the magnetic flux collecting convex portion 34b of the first magnetic flux collecting yoke 35 and the magnetic flux collecting convex portion 35b of the second magnetic flux collecting yoke 35 within the magnetic gap. It is arranged at an ideal position parallel to the opposite surface and at the center of the opposite surface. As described above, the magnetic sensor 48 is arranged in parallel to the opposing surfaces of the magnetism collecting convex portions 34b and the magnetism collecting convex portions 35b and at the center of the opposing surfaces, so that the incident angle of the induced magnetic flux on the magnetic sensor 48 is vertical. Therefore, the detection sensitivity of the magnetic flux density of the magnetic sensor 48 is improved, and the detection accuracy of the torque sensor 100 is improved.

  According to the above embodiment, there exist the effects shown below.

  When the magnetic sensor 48 is mounted on the circuit board 47 at a desired angle, the magnetic sensor 48 is inclined with respect to the opposing surface of the magnetism collecting convex portion 34b and the magnetism collecting convex portion 35b within the magnetic gap. It will be. However, in this embodiment, since the magnetic sensor 48 is positioned and supported by the circuit board 47 via the support member 50, the magnetic sensor 48 is prevented from being mounted on the circuit board 47 at a desired angle. The Therefore, since the magnetic sensor 48 is prevented from being inclined and disposed in the magnetic gap, the incident angle of the induced magnetic flux with respect to the magnetic sensor 48 becomes vertical, and the magnetic sensor 48 detects the sensitivity of the magnetic flux density. Therefore, the detection accuracy of the torque sensor 100 can be increased.

  In addition, the magnetic gap can be narrowed by preventing the tilt of the magnetic sensor 48 within the magnetic gap. Thereby, since the detection sensitivity of the magnetic flux density of the magnetic sensor 48 improves, the detection accuracy of the torque sensor 100 can be improved.

  Further, when the magnetic sensor 48 is mounted on the circuit board 47 at a desired angle, the magnetic sensor 48 is inserted into the magnetic gap when the magnetic sensor 48 is arranged in the magnetic gap. Otherwise, the magnetic sensor 48 may be damaged due to interference with the second magnetic flux collecting yoke 35. However, in the present embodiment, the magnetic sensor 48 is supported on the circuit board 47 via the support member 50, and the magnetic sensor 48 is prevented from being mounted on the circuit board 47 at a desired angle. The magnetic sensor 48 is prevented from interfering with the first magnetism collecting yoke 34 and the second magnetism collecting yoke 35 when the magnet 48 is inserted and arranged in the magnetic gap. Further, when the magnetic sensor 48 is inserted and disposed in the magnetic gap, the claw piece 60 of the holding portion 52 of the support member 50 comes into contact with the first magnetic collecting yoke 34 or the second magnetic collecting yoke 35, and the magnetic sensor 48. Is prevented from directly interfering with the first magnetism collecting yoke 34 and the second magnetism collecting yoke 35. Therefore, damage to the magnetic sensor 48 can be prevented.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  In the above embodiment, the case where the first magnetism collecting ring 32 and the first magnetism collecting yoke 34 are formed separately has been described. However, the first magnetism collecting ring 32 and the first magnetism collecting yoke 34 may be integrally formed as one member. The same applies to the second magnetism collecting ring 33 and the second magnetism collecting yoke 35.

  The present invention can be used as a torque sensor used in an electric power steering device that assists a steering force applied to a steering wheel by a driver.

DESCRIPTION OF SYMBOLS 100 Torque sensor 1 Electric power steering apparatus 11 Input shaft 12 Output shaft 21 Torsion bar 22 Magnetic generating part 23 Ring magnet 25 Rotating magnetic circuit part 31 Fixed magnetic circuit part 40 Sensor holder 48 Magnetic sensor (magnetic detector)
50 Support member 51 Body 51a Positioning surface 51b End surface 51c Insertion portion 51d Recessed portion 52 Holding portion 52a Inner surface 54 Boss 55 Snap fit 56 Lead wire 60 Claw piece 80 Substrate assembly 81 First holder 82 Second holder

Claims (4)

A torque sensor for detecting a torque acting on a torsion bar connecting the first shaft and the second shaft rotatably supported in the housing;
A magnetic generator that rotates with the first shaft;
A rotating magnetic circuit that rotates with the second shaft;
A fixed magnetic circuit portion fixed to the housing;
Magnetic detection that is disposed in a magnetic gap provided in the fixed magnetic circuit unit and detects a magnetic flux density guided to the fixed magnetic circuit unit from the magnetism generating unit through the rotating magnetic circuit unit in accordance with torsional deformation of the torsion bar And
A support member for supporting the magnetic detector on a circuit board,
The support member is
A main body having a positioning surface in surface contact with the surface of the circuit board;
An insertion part formed in the main body part, through which a lead wire electrically connecting the magnetic detector and the circuit board is inserted;
A positioning part formed on the main body part for positioning the main body part with respect to the circuit board;
A pair of holding parts that extend from the main body part along both sides of the magnetic detector and hold the magnetic detector;
The magnetic sensor has a rear surface in surface contact with the main body portion, and both side surfaces are in surface contact with the inner surfaces of the pair of holding portions and are held by the support member.   2. The torque sensor according to claim 1, wherein a claw piece for preventing the magnetic detector from coming off from the pair of holding portions is formed at a tip of the pair of holding portions. The positioning part is a boss that is formed on a positioning surface of the main body part and fits in a positioning hole formed in the circuit board,
3. The main body portion is formed with a locking portion that is locked to a through-hole formed in the circuit board and prevents the support member from falling off the circuit board. The torque sensor described in 1. The main body has a recess formed so as to have a space between the surface of the circuit board and
The torque sensor according to any one of claims 1 to 3, wherein the insertion portion of the main portion is formed to open to the recess.

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