JP2018059741A - Torque sensor manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten the detection accuracy of a torque sensor.SOLUTION: A torque sensor 100 comprises a detection unit assembly 101 for detecting a magnetic flux density guided through a rotary magnetism circuit unit 30 from a magnetism generation unit 20 involving torsional deformation of a torsion bar 5, the detection unit assembly 101 including magnetism-collecting yokes 51, 52 for guiding a magnetic flux from the rotary magnetism circuit unit 30 to magnetism sensors 48, 49, and a non-magnetic case 60 attached to a housing 11. A method of manufacturing the torque sensor 100 includes a positioning step for assembling the magnetism-collecting yokes 51, 52 to the case 60 and positioning the magnetism-collecting yokes 51, 52 and the magnetism sensors 48, 49, and a fixation step for securing the magnetism-collecting yokes 51, 52 to the case 60.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a torque sensor.

  Patent Document 1 discloses a magnetic generation unit fixed to an input shaft, a rotating magnetic circuit unit fixed to an output shaft, a fixed magnetic circuit unit fixed to a housing, and a magnetic flux density guided to the fixed magnetic circuit unit. A torque sensor comprising a magnetic sensor for detection is disclosed.

  The fixed magnetic circuit section includes first and second magnetic flux collecting rings, and first and second magnetic flux collecting yokes that are disposed in contact with the first and second magnetic flux collecting rings and form a magnetic gap therebetween. Prepare. The magnetic sensor is disposed in a magnetic gap formed between the first and second magnetic collecting yokes.

JP 2009-244205 A

  In this type of torque sensor, the metal magnetism collecting yoke is generally formed integrally with a resin case. After the magnetism collecting yoke and the case are integrally molded, the first and second magnetism collecting yokes are formed. A magnetic sensor is inserted into a magnetic gap formed between the yokes.

  When integrally forming the magnetic collecting yoke and the case, it is necessary to manage the position of the magnetic collecting yoke so that they do not interfere with each other in consideration of the dimensional tolerances of the magnetic collecting yoke and the magnetic sensor. It is necessary to determine the size of the magnetic gap between the magnetic collecting yokes. As a result, the gap between the magnetism collecting yoke and the magnetic sensor becomes large, and the detection accuracy of the torque sensor may be deteriorated.

  An object of this invention is to improve the detection accuracy of a torque sensor.

  A first invention is a method of manufacturing a torque sensor that detects torque acting on a torsion bar that connects a first shaft and a second shaft that are rotatably supported in a housing, and the torque sensor is a torsion bar. The sensor assembly includes a detection unit that detects a magnetic flux density guided from the magnetism generation unit through the rotary magnetic circuit unit in accordance with the torsional deformation of the magnet, and the detection unit assembly includes a magnetic detector that detects the magnetic flux density and a magnetic flux from the rotary magnetic circuit unit. A magnetic flux collecting yoke that guides the magnetic sensor to the magnetic detector, and a nonmagnetic case that accommodates the magnetic detector and is attached to the housing. And a positioning step for positioning the magnetic detector, and a fixing step for fixing the magnetism collecting yoke to the case.

  In the first invention, the magnetism collecting yoke is provided separately from the case without being integrally formed with the case, and is assembled to the case. At the time of the assembling, the magnetism collecting yoke and the magnetic detector are positioned.

  According to a second aspect of the present invention, the magnetism collecting yoke is formed along the rotating magnetic circuit portion, and a pair of yoke main bodies disposed at a predetermined interval in the axial direction of the torsion bar, and protrudes from the yoke main body to face each other. And a pair of leg portions on which the magnetic detector is disposed. The case is fitted into an opening formed in the housing, and the magnetic detector is accommodated therein. There is a bottom cylindrical housing part, and a slit for housing the yoke body is formed on the surface of the bottom part of the housing part, and the slit width is larger than the width of the yoke body. The main body is moved in a direction away from or closer to each other to position the leg portion and the magnetic detector.

  In the second invention, since the leg portion can be brought as close as possible to the magnetic detector, the sensitivity of the magnetic detector for detecting the magnetic flux density is improved, and the detection accuracy of the torque sensor is improved.

  According to a third aspect of the present invention, the magnetism collecting yoke further includes a protrusion formed in the yoke body and inserted into a hole formed in the bottom surface of the housing portion, and positioning of the leg portion and the magnetic detector in the positioning step is performed The method is characterized in that it is performed in a state where the protrusion is temporarily fixed to the hole using an adhesive.

  In the third invention, since the positioning of the leg portion and the magnetic detector is performed in a state where the protrusion is temporarily fixed to the hole using the adhesive, the positioning accuracy of the leg portion and the magnetic detector is improved.

  According to a fourth aspect of the present invention, there is provided a holder for fixing the magnetism collecting yoke to the case and a shielding plate for magnetically shielding the magnetic detector against leakage magnetic flux in the rotating magnetic circuit section in the fixing step. And the holder is inserted and fixed in a ring portion disposed along the outer peripheral edge of the bottom surface of the housing portion, and a hole formed to protrude from the ring portion and formed in the bottom surface of the housing portion. And a shielding plate is formed on the bottom surface of the housing portion, the body portion being disposed between the pair of yoke bodies on the bottom surface of the housing portion, and protruding from the body portion. And a torque sensor manufacturing method, as a pre-process of the fixing process, a hole into which the projection of the magnetic flux collecting yoke is inserted, a hole into which the claw part of the holder is inserted, And inject the adhesive into the hole where the claw part of the shielding plate is inserted And further comprising the step.

  In the fourth invention, since the operation of injecting the adhesive into each hole can be performed simultaneously from the bottom surface side, that is, from the same direction, the adhesive injection step can be performed in one step.

  According to the present invention, the detection accuracy of the torque sensor can be increased.

1 is a cross-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 rotating magnetic circuit part. It is a perspective view of a detection part assembly. It is a front view of a detection part assembly. It is a top view of a detection part assembly. It is an exploded view of a detection part assembly. It is a perspective view of a magnetism collection yoke. It is a front view of a detection part assembly, and is a figure which shows the state before attaching a shielding board and a holder. It is a figure which shows the positional relationship of a magnetism collection yoke and a magnetic sensor. It is an exploded view of a detection part assembly, and is a figure showing the state before attaching a holder.

  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. The electric power steering device 1 is a device that is mounted on a vehicle and assists steering of a steering wheel by a driver.

  The electric power steering apparatus 1 includes a steering shaft 2 that is connected to the steering wheel and rotates in accordance with the rotation of the steering wheel, and a rack shaft that steers the wheels in accordance with the rotation of the steering shaft 2.

  The steering shaft 2 includes an input shaft 3 as a first shaft that rotates as the steering wheel is steered by a driver, an output shaft 4 as a second shaft that is linked to a rack shaft that steers wheels, and an input shaft 3. And a torsion bar 5 for connecting the output shaft 4.

  A pinion gear that meshes with a rack gear formed on the rack shaft is formed below the output shaft 4. When the steering wheel is steered, the steering shaft 2 rotates, the rotation is converted into a linear motion of the rack shaft by the pinion gear and the rack gear, and the wheels are steered through the knuckle arm. In addition, the structure which connects the pinion shaft and the output shaft 4 which mesh with a rack shaft via an intermediate shaft may be sufficient.

  The electric power steering apparatus 1 includes a worm wheel coupled to the output shaft 4, a worm shaft that meshes with the worm wheel, and an electric motor that rotationally drives the worm shaft as an assist mechanism that assists the driver in steering. The electric power steering device 1 applies steering assist torque to the output shaft 4 by an electric motor.

  The input shaft 3 is rotatably supported by a metal first housing 11 via a rolling bearing 13. The output shaft 4 is rotatably supported by the metal second housing 12 via a rolling bearing 14. A slide bearing 15 is interposed between the lower end side of the input shaft 3 and the upper end side of the output shaft 4. The input shaft 3 and the output shaft 4 are supported by the first and second housings 11 and 12 so as to be rotatable on the same axis. The first housing 11 and the second housing 12 are fastened via bolts 16.

  The input shaft 3 is formed in a cylindrical shape, and a torsion bar 5 is accommodated coaxially inside the input shaft 3. The upper end portion of the torsion bar 5 is connected to the upper end portion of the input shaft 3 via a pin 17. The lower end portion of the torsion bar 5 protrudes from the lower end opening portion of the input shaft 3, and is connected to the output shaft 4 via a serration 5a. The torsion bar 5 transmits the steering torque input to the input shaft 3 to the output shaft 4 via the steering wheel, and is torsionally deformed about the axis according to the steering torque.

  The electric power steering apparatus 1 is provided with a non-contact type torque sensor 100 that detects a steering torque applied to the torsion bar 5 based on a rotational angle difference between the input shaft 3 and the output shaft 4. Hereinafter, the torque sensor 100 will be described in detail.

  As shown in FIG. 1, the torque sensor 100 includes a magnetism generating unit 20 that is fixed to the input shaft 3 and rotates with the input shaft 3, a rotating magnetic circuit unit 30 that is fixed to the output shaft 4 and rotates with the output shaft 4, A fixed magnetic circuit unit 40 fixed to one housing 11 and a magnetic detector for detecting a magnetic flux density guided from the magnetism generating unit 20 to the fixed magnetic circuit unit 40 through the rotating magnetic circuit unit 30 in accordance with torsional deformation of the torsion bar 5 As a first magnetic sensor 48 and a second magnetic sensor 49 (see FIG. 6). The torque sensor 100 detects the steering torque that acts on the torsion bar 5 based on the outputs of the first magnetic sensor 48 and the second magnetic sensor 49.

  Instead of the above configuration, the magnetism generating unit 20 may be fixed to the output shaft 4 so as to rotate with the output shaft 4, and the rotating magnetic circuit unit 30 may be fixed to the input shaft 3 so as to rotate with the input shaft 3. Good.

  The magnetism generator 20 includes an annular back yoke 21 that is press-fitted into the input shaft 3, and an annular ring magnet 22 that is coupled to the lower end surface of the back yoke 21.

  The ring magnet 22 is a permanent magnet that generates magnetism in the direction of the rotation axis of the input shaft 3. The ring magnet 22 is a multipolar magnet formed by magnetizing a hard magnetic material in the rotation axis direction, and has twelve magnetic poles formed with an equal width in the circumferential direction. That is, six N poles and six S poles are alternately arranged in the circumferential direction on the upper end surface and the lower end surface of the ring magnet 22. The number of magnetic poles formed on the end face of the ring magnet 22 is arbitrarily set within a range of 2 or more.

  The upper magnetic pole surface, which is the upper end surface of the ring magnet 22, is fixed to the lower end surface of the back yoke 21 with an adhesive. Since the back yoke 24 is formed of a soft magnetic material, it is magnetized by the magnetic field exerted by the ring magnet 22 and is attracted to the ring magnet 22. Thus, the back yoke 21 and the ring magnet 22 are coupled by the adhesive force and magnetic force of the adhesive. The back yoke 21 has a function as a connecting member for connecting the ring magnet 22 to the input shaft 3 and a function as a yoke for connecting magnetic poles adjacent to the ring magnet 22 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 and 2, the rotating magnetic circuit unit 30 includes a first soft magnetic ring 31 and a second soft magnetic ring 32 to which a magnetic flux generated from the ring magnet 22 is guided, and an attachment member attached to the output shaft 4. 33 and a molding resin 34 for fixing the first soft magnetic ring 31 and the second soft magnetic ring 32 to the mounting member 33.

  The first soft magnetic ring 31 includes an annular first magnetic path ring portion 31C, six first magnetic path column portions 31B protruding downward from the first magnetic path ring portion 31C, and each first magnetic path column portion. A first magnetic path tip portion 31A that refracts inward from the lower end of 31B and faces the lower end surface of the ring magnet 22; The second soft magnetic ring 32 includes an annular second magnetic path ring portion 32C, six second magnetic path column portions 32B protruding upward from the second magnetic path ring portion 32C, and each second magnetic path column portion. A second magnetic path tip 32A that refracts inward from the upper end of 32B and faces the lower end surface of the ring magnet 22;

  The first soft magnetic ring 31 and the second soft magnetic ring 32 are formed by pressing. The first soft magnetic ring 31 and the second soft magnetic ring 32 are not limited to pressing, and may be formed by casting, sintering, or the like.

  The first magnetic path tip 31A and the second magnetic path tip 32A are formed in a flat plate shape. The first magnetic path tip 31A and the second magnetic path tip 32A are arranged on the same plane perpendicular to the rotation axis of the torsion bar 5 at equal intervals alternately in the circumferential direction around the rotation axis. . Further, the first magnetic path tip portion 31A and the second magnetic path tip portion 32A are in a neutral state where no torque acts on the torsion bar 5, and the respective center lines extending in the radial direction of the torsion bar 5 are the ring magnets 22. It arrange | positions so that the boundary of N pole and S pole may be pointed.

  The first magnetic path column portion 31 </ b> B and the second magnetic path column portion 32 </ b> B are each formed in a flat plate shape and extend in the direction of the rotation axis of the torsion bar 5. The first magnetic path column portion 31B is disposed so as to surround the outer peripheral surface of the ring magnet 22 with a predetermined gap. The first magnetic path column portion 31 </ b> B is provided so as not to short-circuit the magnetic flux of the ring magnet 22. The second magnetic path column portion 32 </ b> B extends in the direction opposite to the first magnetic path column portion 31 </ b> B along the rotation axis of the torsion bar 5.

  The first magnetic path ring part 31C and the second magnetic path ring part 32C are arranged on a plane orthogonal to the rotation axis of the torsion bar 5, and are formed in an annular shape with the entire circumference connected. The first magnetic path ring portion 31 </ b> C and the second magnetic path ring portion 32 </ 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 31 </ b> C is disposed above the lower end surface of the ring magnet 22, and the second magnetic path ring portion 32 </ b> C is disposed below the ring magnet 22. That is, the ring magnet 22 is disposed between the first magnetic path ring portion 31C and the second magnetic path ring portion 32C in the rotation axis direction of the torsion bar 5.

  As shown in FIG. 1, the fixed magnetic circuit unit 40 includes an annular first magnetic flux collecting ring 41 provided along the outer periphery of the first magnetic path ring portion 31 </ b> C of the first soft magnetic ring 31, and a second soft magnetic material. An annular second magnetic flux collecting ring 42 provided along the outer circumference of the second magnetic path ring portion 32C of the ring 32, and a first magnetic flux collecting yoke 51 disposed in contact with the outer circumferential surface of the first magnetic flux collecting ring 41. (See FIG. 3) and a second magnetism collecting yoke 52 (see FIG. 3) disposed in contact with the outer peripheral surface of the second magnetism collecting ring 42.

  The first magnetism collecting ring 41 and the second magnetism collecting ring 42 have a C shape in which slits are partially formed, and are caulked and fixed to the inner peripheral surface of the first housing 11. The inner peripheral surface of the first magnetic flux collecting ring 41 faces the first magnetic path ring portion 31C of the first soft magnetic ring 31, and the inner peripheral surface of the second magnetic flux collecting ring 42 is the second magnetic field of the second soft magnetic ring 32. It faces the road ring portion 32C.

  As described above, the first magnetism collecting ring 41 and the second magnetism collecting ring 42 are arranged on the outer periphery of the rotating magnetic circuit unit 30 to alleviate the influence of the rotational shake and eccentricity of the rotating magnetic circuit unit 30 and thereby the first magnetic sensor. 48 and a function of guiding the magnetic flux to the second magnetic sensor 49 side.

  Note that the first magnetism collecting ring 41 and the second magnetism collecting ring 42 are not essential components and may be eliminated. In that case, the first magnetic flux collecting yoke 51 is disposed along the first magnetic path ring portion 31C of the first soft magnetic ring 31, and the second magnetic flux collecting yoke 52 is the second soft magnetic ring 32 of the second soft magnetic ring 32. Arranged along the magnetic path ring portion 32C.

  The first magnetism collecting yoke 51 and the second magnetism collecting yoke 52 are provided in the case 60 together with the first magnetic sensor 48 and the second magnetic sensor 49 to constitute the detection unit assembly 101 shown in FIG. Below, with reference to FIGS. 3-10, the detection part assembly 101 is demonstrated in detail.

  The detection unit assembly 101 detects the magnetic flux density guided from the ring magnet 22 through the rotating magnetic circuit unit 30 in accordance with the torsional deformation of the torsion bar 5, and is attached to the first housing 11. FIG. 1 shows a state in which the detection unit assembly 101 is not attached.

  3-6, the detection part assembly 101 comprises the 1st magnetic sensor 48 and the 2nd magnetic sensor 49 which detect magnetic flux density, and a part of fixed magnetic circuit part 40, and the rotation magnetic circuit part 30 The first magnetism collecting yoke 51 and the second magnetism collecting yoke 52 that guide the magnetic flux from the first magnetic sensor 48 and the second magnetic sensor 49, the resin case 60 attached to the first housing 11, and the first magnetism collecting magnet. And a holder 90 for fixing the yoke 51 and the second magnetism collecting yoke 52 to the case 60.

  The detection unit assembly 101 further includes a shielding plate 80 that magnetically shields the first magnetic sensor 48 and the second magnetic sensor 49 against leakage magnetic flux in the rotating magnetic circuit unit 30, and the first magnetic sensor 48 and the second magnetic sensor 48. And a substrate 81 to which the magnetic sensor 49 is connected.

  Hall elements are used for the magnetic sensors 48 and 49. The hall element outputs a voltage corresponding to the magnetic flux density passing therethrough as a signal. The magnetic sensors 48 and 49 output a voltage corresponding to the magnitude and direction of the magnetic flux density to the EPS controller that controls the driving of the electric power steering apparatus 1 through the substrate 81.

  The reason why the two magnetic sensors 48 and 49 are provided in the torque sensor 100 is to perform a failure diagnosis of the torque sensor 100 by comparing the output voltages of the two. In other words, when failure diagnosis of the torque sensor 100 is not performed using a magnetic sensor, the number of magnetic sensors may be one.

  The first magnetism collecting yoke 51 and the second magnetism collecting yoke 52 have the same shape. As shown in FIGS. 6 and 7, the first magnetism collecting yoke 51 has a yoke body 53 formed in a plate shape, and a pair of legs 54 and 55 formed to protrude from the yoke body 53. Similarly, the second magnetism collecting yoke 52 has a yoke body 56 formed in a plate shape and a pair of leg portions 57 and 58 formed so as to protrude from the yoke body 56.

  The magnetism collecting yokes 51 and 52 are formed by pressing. Since the workpiece formed by press working has a higher density than the sintered material, the magnetic permeability is high and the magnetic hysteresis is also small. Therefore, the detection accuracy of the torque sensor 100 can be increased. However, since the material to be processed must be thinned by press working, the obtained magnetic collecting yokes 51 and 52 are also formed into thin plate shapes. For this reason, when the magnetism collecting yokes 51 and 52 are integrally formed with the resin case 60, the magnetism collecting yokes 51 and 52 are affected by the influence of the molding pressure at the time of integral molding and the stress due to the shrinkage of the molding resin after molding. This causes a decrease in magnetic susceptibility and an increase in magnetic hysteresis. Therefore, in the present embodiment, the magnetism collecting yokes 51 and 52 are not formed integrally with the case 60 but are provided separately from the case 60 and fixed by the holder 90.

  The yoke bodies 53 and 56 have arcuate portions 53a and 56a formed in an arc shape so that the inner peripheral surfaces thereof are in contact with the outer peripheral surfaces of the magnetism collecting rings 41 and 42. Since the magnetism collecting rings 41 and 42 are provided along the magnetic path ring portions 31C and 32C of the soft magnetic rings 31 and 32, the arc portions 53a and 56a are also formed of the magnetic path ring portions 31C and 32C of the soft magnetic rings 31 and 32. It will be formed along. As described above, the yoke bodies 53 and 56 are formed along the rotary magnetic circuit unit 30.

  Flat plate portions 53b and 56b are formed at both ends of the arc portions 53a and 56a. On the flat plate portions 53b and 56b, spherical protrusions 53c and 56c are formed on the outer peripheral surface side of the arc portions 53a and 56a.

  The yoke body 53 and the yoke body 56 are arranged in parallel to each other with a predetermined interval in the axial direction of the torsion bar 5 (see FIGS. 3 and 4).

  The pair of leg portions 54 and 55 of the first magnetic flux collecting yoke 51 are arranged at a predetermined interval in the circumferential direction of the rotating magnetic circuit portion 30. Similarly, the pair of leg portions 57 and 58 of the second magnetism collecting yoke 52 are also arranged at a predetermined interval in the circumferential direction of the rotating magnetic circuit portion 30. The leg portions 54, 55 and the leg portions 57, 58 are formed to extend radially outward from the mutually opposing end surfaces of the yoke bodies 53, 56 and in a direction approaching each other. The claw portions 54a and 55a formed at the tips of the leg portions 54 and 55 and the claw portions 57a and 58a formed at the tips of the leg portions 57 and 58 are opposed to each other with a magnetic gap as a predetermined gap. (See FIG. 9). That is, a pair of magnetic gaps arranged in the circumferential direction is formed between the first magnetism collecting yoke 51 and the second magnetism collecting yoke 52. A first magnetic sensor 48 and a second magnetic sensor 49 are disposed in the pair of magnetic gaps, respectively.

  The claw portions 54a, 55a, 57a, 58a are formed in a flat plate shape. The claw portion 54a and the claw portion 57a are arranged in parallel to each other, and the first magnetic sensor 48 is arranged so as to be sandwiched between the claw portion 54a and the claw portion 57a. Similarly, the claw portion 55a and the claw portion 58a are arranged in parallel to each other, and the second magnetic sensor 49 is arranged so as to be sandwiched between the claw portion 55a and the claw portion 58a (see FIG. 9).

  The magnetic collecting yokes 51 and 52 have a function of collecting the magnetic flux from the rotating magnetic circuit unit 30 to the magnetic sensors 48 and 49.

  As shown in FIGS. 3 to 6, the case 60 is fitted to an opening 11 a (see FIG. 1) formed in the first housing 11 and has a bottomed cylindrical sensor in which the magnetic sensors 48 and 49 are accommodated. The housing portion 61, the substrate housing portion 62 in which the substrate 81 is housed, a cover 63 that seals the opening of the substrate housing portion 62, and the sensor housing portion 61 project radially from the outer periphery, 1 includes a collar portion 64 fastened to the housing 11 and a connector 65 for electrically connecting the substrate 81 and the EPS controller. The case 60 is made of resin, but is not limited to resin and may be made of a nonmagnetic material.

  The opening 11 a (see FIG. 1) is formed through the first housing 11. In a state where the case 60 is not attached to the opening 11a (the state shown in FIG. 1), the rotating magnetic circuit unit 30 and the magnetism collecting rings 41 and 42 provided in the first housing 11 face the opening 11a.

  The case 60 is attached to the first housing 11 through a bolt that passes through the bolt insertion hole 64a of the flange portion 64 while the sensor accommodating portion 61 is fitted into the opening portion 11a of the first housing 11.

  The sensor housing portion 61 includes a cylindrical portion 66 whose outer peripheral surface 66a is fitted into the opening portion 11a, and a bottom portion 67 that is formed at an end portion of the cylindrical portion 66 and seals the opening portion 11a.

  An O-ring 18 (see FIG. 1) is provided on the inner peripheral surface of the opening 11a to seal between the cylindrical portion 66 and the outer peripheral surface 66a. This prevents muddy water or the like from entering the first housing 11 from the outside through the space between the opening portion 11a and the cylindrical portion 66.

  The internal space of the sensor accommodating portion 61 and the internal space of the substrate accommodating portion 62 communicate with each other, and the first magnetic sensor 48 and the second magnetic sensor 49 connected to the substrate 81 accommodated in the substrate accommodating portion 62 are sensor accommodating. Arranged in the part 61. As shown in FIG. 6, the first magnetic sensor 48 and the second magnetic sensor 49 are connected to the substrate 81 via pins 82 extending vertically from one surface of the substrate 81, and are arranged at a predetermined interval. .

  The surface facing the first housing 11 at the bottom 67 of the sensor accommodating portion 61, that is, the surface 68 of the bottom 67 is formed on the arc surface 68 a formed along the magnetism collecting rings 41, 42, and the circumferential ends of the arc surface 68 a. And a formed plane 68b. That is, the plane 68b is formed on the mountain side at both ends of the arc surface 68a. The arc portions 53a and 56a of the yoke bodies 53 and 56 are disposed along the arc surface 68a, and the flat plate portions 53b and 56b of the yoke bodies 53 and 56 are disposed along the plane 68b.

  As shown in FIG. 6, a pair of slits 71 and 72 for accommodating the yoke main body 53 and the yoke main body 56 are formed on the surface 68 of the bottom 67 across the arc surface 68a and the flat surface 68b. The pair of slits 71 and 72 are formed in parallel with each other with a predetermined interval.

  The slits 71 and 72 are formed as arc-shaped grooves so that the yoke bodies 53 and 56 are accommodated. The depth of the slits 71 and 72 is smaller than the thickness of the yoke main bodies 53 and 56. Thereby, in a state where the yoke main bodies 53 and 56 are accommodated in the slits 71 and 72, a part of the yoke main bodies 53 and 56 is exposed from the slits 71 and 72. Further, the widths (heights) of the slits 71 and 72 in the axial direction of the torsion bar 5 are larger than the widths (heights) of the yoke bodies 53 and 56. As a result, when the magnetic flux collecting yokes 51 and 52 are assembled to the case 60, the yoke bodies 53 and 56 can be moved away from or closer to each other in the slits 71 and 72. Thus, the magnetic flux collecting yokes 51 and 52 can be slid onto the case 60 when assembled to the case 60. Therefore, when the magnetism collecting yokes 51 and 52 are assembled to the case 60, the claw portions 54a and 57a and the first magnetic sensor 48 can be positioned, and the claw portions 55a and 58a and the second magnetic sensor 49 can be positioned. it can.

  Holes 73 into which the protrusions 53c and 56c formed on the yoke bodies 53 and 56 are inserted are formed in the plane 68b on the surface 68 of the bottom 67 on both sides of the slits 71 and 72. An adhesive is injected into the hole 73, and the protrusions 53c and 56c and the hole 73 are fixed via the adhesive. The diameter of the hole 73 is sufficiently larger than the diameter of the protrusions 53c and 56c. Therefore, when the magnetic flux collecting yokes 51 and 52 are assembled to the case 60, the yoke bodies 53 and 56 can be moved in the slits 71 and 72 even when the protrusions 53 c and 56 c are inserted into the holes 73.

  The bottom portion 67 includes through holes 74 and 75 through which the pair of leg portions 54 and 55 of the first magnetic flux collecting yoke 51 are inserted between the slit 71 and the slit 72, and the pair of leg portions 57 of the second magnetic flux collecting yoke 52. , 58 are inserted therethrough. Specifically, the through holes 74 to 77 are formed so as to open to the arc surface 68 a on the surface 68 of the bottom 67. The through holes 74 to 77 are sufficiently larger than the outer shapes of the leg portions 54, 55, 57, and 58. Therefore, the yoke bodies 53 and 56 can be moved in the slits 71 and 72 even when the leg portions 54, 55, 57 and 58 are inserted through the through holes 74 to 77.

  The holder 90 is formed to protrude from the ring portion 91 in the central axis direction of the ring portion 91 in order to fix the yoke main bodies 53 and 56 to the surface 68 of the bottom portion 67, and to prevent the holder 90 from falling off. Claw portion 92.

  The ring portion 91 is disposed along the outer peripheral edge of the surface 68 of the bottom portion 67 and is formed in a shape corresponding to the arc surface 68 a and the flat surface 68 b on the surface 68 of the bottom portion 67. Specifically, the ring portion 91 includes a pair of curved portions 91a formed by being bent along the arc surface 68a, and a pair of flat plate portions 91b formed in a plate shape along the flat surface 68b.

  The yoke bodies 53 and 56 are fixed to the surface 68 of the bottom portion 67 by arranging the ring portions 91 so as to overlap both ends. Specifically, the flat plate portions 53b and 56b formed at both ends of the yoke main bodies 53 and 56 are sandwiched between the flat surface 68b of the bottom portion 67 and the flat plate portion 91b of the ring portion 91, whereby the yoke main body 53, 56 is fixed. Thus, the yoke bodies 53 and 56 are fixed by being sandwiched between the case 60 and the holder 90.

  The claw portions 92 are formed to be coupled to a pair of first claw portions 92a formed to be coupled to the inner peripheral surfaces of the pair of curved portions 91a and to an inner peripheral surface of the pair of flat plate portions 91b, respectively. A pair of second claw portions 92b is formed. The pair of first claw portions 92a is formed at a symmetrical position with respect to the center of the ring portion 91, and the pair of second claw portions 92b is formed at a symmetrical position with respect to the center of the ring portion 91. The portion 92a and the second claw portion 92b are formed 90 degrees apart.

  Holes 78 into which the pair of first claw portions 92a are respectively inserted are formed in the arc surface 68a on the surface 68 of the bottom portion 67. Further, holes 79 into which the pair of second claw portions 92b are respectively inserted are formed in the plane 68b on the surface 68 of the bottom 67. An adhesive is injected into the holes 78 and 79, and the first claw portion 92a and the hole 78, and the second claw portion 92b and the hole 79 are fixed via the adhesive.

  The shielding plate 80 is formed on the surface 68 of the bottom portion 67 so as to protrude from the main body portion 80a disposed between the yoke main body 53 and the yoke main body 56, and both ends of the main body portion 80a, and prevents the shielding plate 80 from falling off. A pair of claw portions 80b.

  The main body portion 80a is disposed so as to close a part of the through holes 74 to 77. Therefore, the shielding plate 80 also has a function of preventing the magnetic collecting yokes 51 and 52 from falling off from the bottom 67.

  By disposing the main body 80a of the shielding plate 80 between the yoke main body 53 and the yoke main body 56, leakage magnetic flux in the rotary magnetic circuit unit 30 is guided to the shielding plate 80 and reaches the magnetic sensors 48 and 49. Disappear. Thus, since the magnetic sensors 48 and 49 are magnetically shielded against the leakage magnetic flux in the rotating magnetic circuit unit 30 by the shielding plate 80, the leakage magnetic flux that is not related to the torsional deformation of the torsion bar 5 is obtained. Unaffected by change. Therefore, the detection accuracy of the torque sensor 100 is increased.

  Holes 83 into which the pair of claws 80b are respectively inserted are formed in the plane 68b on the surface 68 of the bottom 67. An adhesive is injected into the hole 83, and the claw portion 80b and the hole 83 are fixed via the adhesive.

  The hole 79 into which the pair of second claw portions 92b of the holder 90 is inserted and the hole 83 into which the pair of claw portions 80b of the shielding plate 80 are inserted are formed in communication. That is, the hole 79 and the hole 83 are formed as one hole. Accordingly, the adhesive can be injected into the holes 79 and 83 at the same time. Further, since the pair of second claw portions 92b of the holder 90 and the pair of claw portions 80b of the shielding plate 80 are inserted into the same hole, the second claw portions 92b and the claw portions 80b come into contact with each other and bias each other. Fit. Therefore, since the holder 90 and the shielding plate 80 are integrated via the claw portion 92b and the claw portion 80b, the holder 90 and the shielding plate 80 are prevented from falling off from the bottom portion 67.

  Below, the detection method of the steering torque which acts on the torsion bar 5 by the torque sensor 100 is demonstrated.

  In a neutral state where no torque acts on the torsion bar 5, the first magnetic path tip portion 31 A of the first soft magnetic ring 31 and the second magnetic path tip portion 32 A of the second soft magnetic ring 32 are each N of the ring magnet 22. 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 30 and the fixed magnetic circuit unit 40.

  When a torque in a specific direction acts on the torsion bar 5 by the operation of the steering wheel by the driver, the torsion bar 5 is torsionally deformed according to the direction of the torque. When the torsion bar 5 is torsionally deformed, the first magnetic path tip 31A faces the N pole with a larger area than the S pole, while the second magnetic path tip 32A has the S pole larger than the N pole. Confront. The magnetic flux from the ring magnet 22 is guided to the fixed magnetic circuit unit 40 through the rotating magnetic circuit unit 30. Specifically, the first soft magnetic ring 31, the first magnetic flux collecting ring 41, the first magnetic flux collecting yoke 51, the second magnetic flux collecting yoke 52, the second magnetic flux collecting ring 42, and the second soft magnetic ring 32 are arranged from the N pole. This is a route that goes to the south pole. The first magnetic sensor 48 and the second magnetic sensor 49 installed in the magnetic gap between the first magnetic collecting yoke 51 and the second magnetic collecting yoke 52 output voltage values 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 5 by the operation of the steering wheel by the driver, the torsion bar 5 is twisted and deformed in the reverse direction according to the direction of the torque. When the torsion bar 5 is torsionally deformed, the first magnetic path tip 31A confronts with a larger area than the N pole in the S pole, while the second magnetic path tip 32A has a larger area in the N pole than the S pole. Confront. The magnetic flux from the ring magnet 22 is guided to the fixed magnetic circuit unit 40 through the rotating magnetic circuit unit 30, but the path is opposite to the above. Specifically, the second soft magnetic ring 32, the second magnetic flux collecting ring 42, the second magnetic flux collecting yoke 52, the first magnetic flux collecting yoke 51, the first magnetic flux collecting ring 41, and the first soft magnetic ring 31 are arranged from the N pole. This is a route that goes to the south pole. The first magnetic sensor 48 and the second magnetic sensor 49 installed in the magnetic gap between the first magnetic collecting yoke 51 and the second magnetic collecting yoke 52 output voltage values corresponding to the magnitude and direction of the magnetic flux.

  As the steering torque input to the steering wheel by the driver's operation increases, the amount of torsional deformation of the torsion bar 5 increases. Therefore, the area where the first magnetic path tip 31A faces the N pole and S pole of the ring magnet 22 The difference and the area difference between the second magnetic path tip 32A and the north and south poles of the ring magnet 22 increase, and the magnetic flux induced in the magnetic gap increases. In response to this, the output voltages of the first magnetic sensor 48 and the second magnetic sensor 49 also increase. Therefore, the magnetic flux density guided to the first magnetic sensor 48 and the second magnetic sensor 49 can be increased by increasing the number of magnetic poles of the ring magnet 22.

  Next, a manufacturing method of the detection unit assembly 101 will be described mainly with reference to FIGS.

  Before the magnetic flux collecting yokes 51 and 52 are assembled to the case 60, the substrate 81 is accommodated in the substrate accommodating portion 62 of the case 60 and the opening of the substrate accommodating portion 62 is sealed with the cover 63. The substrate 81 is caulked by a boss formed in the case 60 and inserted through the hole 81a (see FIG. 6) of the substrate 81, and is fixed to the substrate accommodating portion 62 using an adhesive.

  Next, the hole 73 into which the projections 53c and 56c of the magnetic flux collecting yokes 51 and 52 are inserted, the holes 78 and 79 into which the claw portions 92a and 92b of the holder 90 are inserted, and the claw portion 80b of the shielding plate 80 are inserted. An adhesive is injected into the hole 83 (adhesive injection step). Since all the holes 73, 78, 79, 83 are formed to open on the surface 68 of the bottom portion 67, the operation of injecting the adhesive into each of the holes 73, 78, 79, 83 is performed on the surface 68 side of the bottom portion 67. From the same direction. Thus, the adhesive injection process can be performed in one process.

  Next, as shown in FIG. 8, the magnetism collecting yokes 51 and 52 are assembled to the case 60. Specifically, in the first magnetism collecting yoke 51, the pair of leg portions 54 and 55 are inserted into the through holes 74 and 75, and the projection 53 c is inserted into the hole 73 to accommodate the yoke body 53 in the slit 71. Is assembled to the case 60. The second magnetism collecting yoke 52 has a case 60 in which the pair of leg portions 57 and 58 are inserted into the through holes 76 and 77 and the projection 56 c is inserted into the hole 73 to accommodate the yoke body 56 in the slit 72. Assembled into. Since the adhesive is previously injected into the hole 73 into which the protrusions 53 c and 56 c are inserted, the protrusions 53 c and 56 c are temporarily fixed in the hole 73. That is, the first magnetism collecting yoke 51 and the second magnetism collecting yoke 52 are temporarily fixed to the case 60.

  In this state, the claw portions 54a, 57a formed at the front ends of the leg portions 54, 57 and the first magnetic sensor 48 are positioned, and the claw portions 55a, 58a formed at the front ends of the leg portions 55, 58 and the second Positioning with the magnetic sensor 49 is performed. Specifically, as shown by arrows in FIG. 9, the yoke main bodies 53 and 56 are moved in the slits 71 and 72 in a direction away from or closer to each other (positioning step).

  The magnetic flux collecting yokes 51 and 52 are not formed integrally with the case 60 but are provided separately and assembled to the case 60. Therefore, when the magnetic flux collecting yokes 51 and 52 are assembled, the claw portions 54a and 57a and the first magnetic sensor 48 And the positioning of the claw portions 55a and 58a and the second magnetic sensor 49 can be performed. Therefore, the claw portions 54a and 57a can be as close as possible to the first magnetic sensor 48, and the claw portions 55a and 58a can be as close as possible to the second magnetic sensor 49. Thereby, the sensitivity of magnetic flux density detection of the magnetic sensors 48 and 49 is improved, and the detection accuracy of the torque sensor 100 is improved.

  The positioning of the claw portions 54a and 57a and the first magnetic sensor 48 and the positioning of the claw portions 55a and 58a and the second magnetic sensor 49 may be performed by an operator's sense or the claw portions 54a and 57a. The contact load between the first magnetic sensor 48 and the contact load between the claw portions 55a, 58a and the second magnetic sensor 49 may be detected using a sensor or the like, and the detection may be performed based on the detected contact load. .

  Next, as shown in FIG. 10, the shielding plate 80 is assembled to the case 60. Specifically, the shielding plate 80 is assembled to the case 60 by inserting a pair of claw portions 80 b into the holes 83.

  Finally, the holder 90 is assembled to the case 60. Specifically, the holder 90 is assembled to the case 60 by inserting the pair of first claw portions 92 a into the holes 78 and inserting the pair of second claw portions 92 b into the holes 79.

  When the holder 90 is assembled to the case 60, the flat plate portion 91 b of the ring portion 91 overlaps the flat plate portions 53 b and 56 b at both ends of the yoke main bodies 53 and 56, and the yoke main bodies 53 and 56 are on the surface 68 of the bottom 67 in the case 60. (Fixing process). Thus, the magnetism collecting yokes 51 and 52 are fixed to the case 60 via the holder 90.

  As described above, the detection unit assembly 101 is assembled and manufactured.

  The detection unit assembly 101 has a cylindrical portion 66 of the sensor housing portion 61 fitted into the opening 11a of the first housing 11 and is attached to the first housing 11 via a bolt that passes through the bolt insertion hole 64a of the flange portion 64. It is attached.

  In a state where the detection unit assembly 101 is attached to the first housing 11, the inner peripheral surfaces of the yoke bodies 53 and 56 disposed on the surface 68 of the bottom 67 in the cylindrical unit 66 are fixed to the first housing 11. It contacts the outer peripheral surfaces of the rings 41 and 42, respectively. As a result, a magnetic path between the magnetic flux collecting rings 41 and 42 and the magnetic flux collecting yokes 51 and 52 is formed.

  Since the holder 90 for fixing the magnetic flux collecting yokes 51 and 52 is provided on the surface 68 of the bottom 67, there is a concern that the magnetic flux collecting rings 41 and 42 may interfere with each other. However, since the ring portion 91 of the holder 90 that fixes the magnetic flux collecting yokes 51 and 52 is disposed along the outer peripheral edge of the surface 68 of the bottom portion 67, it does not interfere with the magnetic flux collecting rings 41 and 42. More specifically, since the flat plate portion 91b of the ring portion 91 is formed in a flat plate shape along the flat surface 68b of the surface 68, it is positioned in a dead space between the bottom portion 67 and the magnetic flux collecting rings 41 and 42. That is, there is no interference with the magnetism collecting rings 41 and 42.

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

  The magnetism collecting yokes 51 and 52 are fixed to the case 60 by a holder 90. That is, the magnetic flux collecting yokes 51 and 52 are not formed integrally with the case 60 but are provided separately from the case 60 and fixed by the holder 90. As described above, the magnetic flux collecting yokes 51 and 52 have the plate-like yoke main bodies 53 and 56, but are not integrally formed with the resin case 60, so that the yoke main bodies 53 and 56 are not deformed. Therefore, the detection accuracy of the torque sensor 100 using the magnetic collecting yokes 51 and 52 having the plate-like yoke bodies 53 and 56 can be increased.

  Further, the magnetism collecting yokes 51 and 52 are not integrally formed with the case 60 but are provided separately and assembled to the case 60. During the assembly, the claw portions 54a and 57a and the first magnetic sensor 48 are positioned, and the claw portions 55a and 58a and the second magnetic sensor 49 are positioned. Therefore, the claw portions 54a and 57a can be as close as possible to the first magnetic sensor 48, and the claw portions 55a and 58a can be as close as possible to the second magnetic sensor 49. Therefore, the detection accuracy of the torque sensor 100 is increased. be able to.

  Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.

  A method of manufacturing a torque sensor 100 that detects torque acting on a torsion bar 5 that connects an input shaft (first shaft) 3 and an output shaft (second shaft) 4 rotatably supported in housings 11 and 12. The torque sensor 100 includes a magnetism generating unit 20 that rotates with the input shaft 3, a rotating magnetic circuit unit 30 that rotates with the output shaft 4, and a rotating magnet circuit from the magnetism generating unit 20 as the torsion bar 5 is twisted. A detection unit assembly 101 that detects a magnetic flux density guided through the unit 30. The detection unit assembly 101 includes magnetic sensors (magnetic detectors) 48 and 49 that detect the magnetic flux density, and a magnetic flux from the rotating magnetic circuit unit 30. Collecting magnetic yokes 51 and 52 for guiding the magnetic sensors 48 and 49 and the magnetic sensors 48 and 49 to the housing 11 A nonmagnetic case 60, and the torque sensor 100 is manufactured by assembling the magnetism collecting yokes 51 and 52 to the case 60 and positioning the magnetism collecting yokes 51 and 52 and the magnetic sensors 48 and 49. A fixing step of fixing the magnetic flux collecting yokes 51 and 52 to the case 60.

  In this configuration, the magnetic flux collecting yokes 51 and 52 are not formed integrally with the case 60 but are provided separately and assembled to the case 60. When the magnetic flux collecting yokes 51 and 52 and the magnetic sensors 48 and 49 are assembled. Positioning is performed. Therefore, the detection accuracy of the torque sensor 100 can be increased.

  The magnetic flux collecting yokes 51 and 52 are formed along the rotary magnetic circuit unit 30, and are arranged from a pair of yoke main bodies 53 and 56 disposed at a predetermined interval in the axial direction of the torsion bar 5, and the yoke main bodies 53 and 56. The case 60 has a pair of legs 54, 55, 57, and 58 that are formed so as to protrude and face each other, and between which the magnetic sensors 48 and 49 are disposed, and the case 60 is an opening formed in the housing 11. The bottom portion surface 68 of the housing portion 61 accommodates the yoke main bodies 53 and 56. The slit 61 is fitted into the portion 11a and has a bottomed cylindrical housing portion 61 in which the magnetic sensors 48 and 49 are housed. 71 and 72 are formed, and the width of the slits 71 and 72 is larger than the width of the yoke bodies 53 and 56. Thereby positioning the leg portion 54,55,57,58 and the magnetic sensor 48, 49 is moved in the direction.

  In this configuration, the legs 54, 55, 57, and 58 can be brought as close as possible to the magnetic sensors 48 and 49. Therefore, the sensitivity of the magnetic sensors 48 and 49 for detecting the magnetic flux density is improved, and the detection accuracy of the torque sensor 100 is improved. To do.

  The magnetism collecting yokes 51 and 52 are further formed on the yoke main bodies 53 and 56, and further have protrusions 53c and 56c inserted into holes 73 formed on the bottom surface 68 of the accommodating portion 61, and the leg portions 54 in the positioning step. , 55, 57, 58 and the magnetic sensors 48, 49 are positioned in a state where the protrusions 53c, 56c are temporarily fixed in the hole 73 using an adhesive.

  In this configuration, the legs 54, 55, 57, 58 and the magnetic sensors 48, 49 are positioned in a state in which the protrusions 53c, 56c are temporarily fixed in the hole 73 using an adhesive. The positioning accuracy of the magnetic sensors 57 and 58 and the magnetic sensors 48 and 49 is improved.

  In the fixing process, the detection unit assembly 101 magnetically shields the magnetic sensors 48 and 49 against leakage flux from the holder 90 and the rotating magnetic circuit unit 30 for fixing the magnetic collecting yokes 51 and 52 to the case 60. The holder 90 further includes a ring portion 91 disposed along the outer peripheral edge of the bottom surface 68 of the housing portion 61, and a bottom surface 68 of the housing portion 61 formed to protrude from the ring portion 91. And a claw portion 92 that is inserted into and fixed to the holes 78 and 79 formed in the base plate. The shielding plate 80 is disposed between the pair of yoke bodies 53 and 56 on the bottom surface 68 of the housing portion 61. A method of manufacturing the torque sensor 100 includes a main body portion 80a and a claw portion 80b that protrudes from the main body portion 80a and is fixed by being inserted into a hole 83 formed in the bottom surface 68 of the housing portion 61. Solid As a pre-process, a hole 73 into which the projections 53c and 56c of the magnetic flux collecting yokes 51 and 52 are inserted, holes 78 and 79 into which the claw portion 92 of the holder 90 is inserted, and a claw portion 80b of the shielding plate 80 are inserted. And a step of injecting an adhesive into the hole 83.

  In this configuration, the operation of injecting the adhesive into each of the holes 73, 78, 79, 83 can be performed simultaneously from the bottom surface 86 side, that is, from the same direction, so the adhesive injection process is performed in one step. Can do.

  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 present embodiment, the through holes 74 to 77 through which the leg portions 54, 55, 57, and 58 are inserted are formed independently. However, the through hole 74 and the through hole 76 may be connected to form one through hole, and the through hole 75 and the through hole 77 may be connected to form one through hole. Alternatively, all the through holes 74 to 77 may be connected to form one through hole. When the through holes are formed in this way, the relative positions of the claw portions 54a and 57a and the first magnetic sensor 48 and the claw portions 55a and 58a and the second magnetic sensor 49 through the through hole from the surface 68 side of the bottom 67. There is an advantage that the claw portions 54a and 57a and the first magnetic sensor 48 can be positioned, and the claw portions 55a and 58a and the second magnetic sensor 49 can be positioned while visually recognizing the relative positions of the claw portions 54a and 57a.

DESCRIPTION OF SYMBOLS 100 ... Torque sensor, 101 ... Detection part assembly, 1 ... Electric power steering device, 3 ... Input shaft (1st shaft), 4 ... Output shaft (2nd shaft), 5. .. Torsion bar, 11... First housing, 20... Magnetism generating part, 22... Ring magnet, 30 .. rotating magnetic circuit part, 31 and 32. Fixed magnetic circuit section, 41, 42 ... magnetic collecting ring, 48, 49 ... magnetic sensor (magnetic detector), 51, 52 ... magnetic collecting yoke, 53, 56 ... yoke body, 53a , 56a ... arc part, 53b, 56b ... flat plate part, 53c, 56c ... projection, 54, 55, 57, 58 ... leg part, 54a, 55a, 57a, 58a ... claw part , 60 ... Case, 61 ... Sensor housing 62 ... Board housing part, 65 ... Connector, 66 ... Cylinder part, 67 ... Bottom part, 68 ... Surface, 71,72 ... Slit, 73 ... Hole, 78,79 ... Hole, 80 ... Shielding plate, 80a ... Main body part, 80b ... Claw part, 81 ... Substrate, 83 ... Hole, 90 ... Holder, 91 ... Ring part 91a ... curved portion, 91b ... flat plate portion, 92a, 92b ... claw portion

Claims (4)

A torque sensor manufacturing method for detecting torque acting on a torsion bar that connects a first shaft and a second shaft rotatably supported in a housing,
The torque sensor
A magnetic generator that rotates with the first shaft;
A rotating magnetic circuit that rotates with the second shaft;
A detection unit assembly that detects a magnetic flux density guided from the magnetism generation unit through the rotating magnetic circuit unit in accordance with the torsional deformation of the torsion bar;
The detection unit assembly is
A magnetic detector for detecting the magnetic flux density;
A magnetic collecting yoke for guiding magnetic flux from the rotating magnetic circuit section to the magnetic detector;
A non-magnetic case that houses the magnetic detector and is attached to the housing;
The method of manufacturing the torque sensor is as follows:
A positioning step of positioning the magnetic flux collecting yoke and the magnetic detector by assembling the magnetic flux collecting yoke to the case;
And a fixing step of fixing the magnetism collecting yoke to the case. The magnetic yoke is
A pair of yoke bodies formed along the rotating magnetic circuit portion and arranged at a predetermined interval in the axial direction of the torsion bar;
A pair of legs that protrude from the yoke body and are opposed to each other, and between which the magnetic detector is disposed,
The case is fitted into an opening formed in the housing, and has a bottomed cylindrical housing portion in which the magnetic detector is housed.
A slit for accommodating the yoke body is formed on the bottom surface of the accommodating portion,
The width of the slit is larger than the width of the yoke body,
2. The torque sensor manufacturing method according to claim 1, wherein, in the positioning step, the leg body and the magnetic detector are positioned by moving the yoke body in a direction away from or closer to each other in the slit. Method. The magnetic yoke is
A protrusion formed on the yoke body and inserted into a hole formed on the bottom surface of the housing;
The torque sensor manufacturing method according to claim 2, wherein the positioning of the leg and the magnetic detector in the positioning step is performed in a state where the protrusion is temporarily fixed to the hole using an adhesive. . The detection unit assembly is
A holder for fixing the magnetism collecting yoke to the case in the fixing step;
A shielding plate for magnetically shielding the magnetic detector against leakage magnetic flux in the rotating magnetic circuit unit,
The holder is
A ring portion disposed along an outer peripheral edge of the bottom surface of the housing portion;
A claw portion that protrudes from the ring portion and is inserted and fixed in a hole formed in the bottom surface of the housing portion,
The shielding plate is
A body portion disposed between a pair of yoke bodies on the bottom surface of the housing portion;
A claw portion that protrudes from the main body portion and is inserted and fixed in a hole formed in the bottom surface of the housing portion,
The method of manufacturing the torque sensor is as follows:
As a pre-step of the fixing step, the hole into which the projection of the magnetism collecting yoke is inserted, the hole into which the claw portion of the holder is inserted, and the hole into which the claw portion of the shielding plate is inserted The method for manufacturing a torque sensor according to claim 3, further comprising a step of injecting an adhesive.

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