JP2004101277A - Torque sensor, electric power steering device using the torque sensor, and manufacturing method for the electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque sensor, simple in structure, dispensing with an electric contact part, and having good accuracy near the neutral point. <P>SOLUTION: This torque sensor 1 is composed of: a torsion bar 4 coaxially connecting an input shaft 2 and an output shaft 3; a ring-like magnet 5 fitted to the end part of the input shaft 2; a set of magnetic yokes 6 fitted to the end of the output shaft 3; a set of magnetism collecting rings 7 disposed close to the outer periphery of the magnetic yokes 6; and a magnetic sensor 8 for detecting the magnetic flux density generated in the magnetism collecting rings 7. In the magnetic yokes 6, claws 6a of the same number as those of N-poles and S-poles of the magnet 5 are provided at equal intervals in the whole periphery. The magnetic yokes 6 and the magnet 5 are disposed without twisting the torsion bar 4 so that the center of the claw 6a provided in the magnetic yoke 6 is aligned with the boundary between the N-pole and S-pole of the magnet 5. The magnetic sensor 8, inserted between a magnetism collecting part 7A1 and a magnetism collecting ring 7B, which are radially opposed to each other, detects the magnetic flux density. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a torque sensor that detects a shaft torque in a mechanism that transmits rotational power, such as an electric power steering device.
[0002]
[Prior art]
As a conventional technique using a magnet and a magnetic sensor, the magnet and the magnetic sensor are fixed to both ends of a torsion bar, and when a torque is applied, the torsion bar is twisted, thereby causing a positional relationship between the magnet and the magnetic sensor. Is changed, and an output proportional to the torque is obtained from the magnetic sensor (for example, see Patent Document 1).
[0003]
The structure is the same as that described above in that a magnet, a magnetic sensor, and a torsion bar are used, but since the torsion of the torsion bar is changed to an axial movement using a gear, the magnetic sensor is mounted on the housing. Since it can be fixed, there is no need for an electrical contact portion for supplying power to the magnetic sensor and extracting a signal (for example, see Patent Document 2).
[0004]
[Patent Document 1]
JP-A-8-159887 (page 4)
[Patent Document 2]
JP-A-6-281513 (page 4)
[0005]
[Problems to be solved by the invention]
However, in the method of Patent Document 1, since the magnet and the magnetic sensor are fixed to the torsion bar, an electric contact portion is required to supply power to the magnetic sensor and take out a signal. Since the slip ring and the brush are used, there is a concern about the reliability of the contact portion.
[0006]
In addition, the method disclosed in Patent Document 2 has a gear mechanism for converting the torsion of the torsion bar into an axial movement. Therefore, the structure is complicated, and errors and errors are caused by backlash of the gear mechanism and wear of the gear. Since a response delay occurs, there is a concern in terms of performance.
[0007]
The present invention has been made based on the above circumstances, and an object of the present invention is to provide a torque sensor having a simple structure, having no electrical contact portion, and having a high accuracy near a neutral point.
[0008]
[Means for Solving the Problems]
In order to solve the above problem, in the torque sensor according to claim 1, a first shaft and a second shaft are coaxially connected, and a torsion torque is applied between the first shaft and the second shaft. Is input, an elastic member that twists around its own axis, a hard magnetic body connected to the first axis to form a magnetic field around it, and a hard magnetic body connected to the second axis and A soft magnetic body having a structure in which a magnetic circuit is formed in a magnetic field formed and a magnetic flux density generated in the magnetic circuit changes when a relative position with respect to the hard magnetic body changes due to the torsion of the elastic member; A pair of auxiliary soft magnetic bodies arranged near the magnetic body and guiding magnetic flux from the soft magnetic body, and a magnetic sensor for detecting a magnetic flux density generated in the auxiliary soft magnetic body, one auxiliary soft magnetic body is , A magnetic flux collector that collects magnetic flux and is provided radially opposite to the other auxiliary soft magnetic body Has a magnetic sensor is characterized in that provided between the magnetism collecting part and the other auxiliary soft magnetic material facing the radial direction.
[0009]
According to the torque sensor of the present invention, when a torsional torque is input between the first shaft and the second shaft and the elastic member is twisted, the relative position between the hard magnetic material and the soft magnetic material changes. The magnetic flux density generated in the magnetic circuit of the soft magnetic material changes. Further, the magnetic flux generated in the soft magnetic material is guided to the auxiliary soft magnetic material, and is collected in the magnetic flux collecting portion provided in one of the auxiliary soft magnetic materials. Therefore, the torsion torque applied between the first axis and the second axis can be determined by detecting the magnetic flux density generated between the magnetic flux collecting part and the other auxiliary soft magnetic body with the magnetic sensor. it can.
[0010]
According to this configuration, the magnetic flux generated from the hard magnetic material does not need to be directly detected by the magnetic sensor, so that the non-contact type magnetic sensor can be fixed and used at a fixed position. As a result, there is no need to provide an electrical contact portion for the magnetic sensor, so that a highly reliable torque sensor can be provided. In addition, by collecting the magnetic flux generated in one auxiliary soft magnetic material in the magnetic flux collecting part, the average of the magnetic flux density generated in the entire circumference of the soft magnetic material can be detected by the magnetic sensor. As a result, it is possible to reduce a detection error due to manufacturing variations, assembly accuracy, center deviation, and the like of components constituting the magnetic circuit. Further, by providing the magnetic sensor between the magnetic flux collecting portion facing in the radial direction and the other auxiliary soft magnetic body, it is possible to suppress an increase in the radial size of the torque sensor.
[0011]
Further, in the torque sensor according to the second aspect, when the first shaft and the second shaft are coaxially connected and a torsional torque is input between the first shaft and the second shaft, An elastic member that twists around its own axis, a hard magnetic body connected to the first axis to form a magnetic field around it, and a hard magnetic body connected to the second axis and formed by the hard magnetic body. A soft magnetic body that has a structure in which the magnetic circuit density is changed when the relative position with the hard magnetic body changes due to the arrangement of the magnetic circuit and the torsion of the elastic member causes the torsion of the elastic member, A set of auxiliary soft magnetic bodies arranged and having a magnetic flux collecting portion for guiding a magnetic flux from the soft magnetic material and collecting the magnetic flux, and a magnetic sensor for detecting a magnetic flux density generated in the auxiliary soft magnetic material via the magnetic flux collecting portion And a magnetic flux collecting portion provided on one auxiliary soft magnetic body and the other auxiliary soft magnetic material. Facing provided in the radial direction magnetic collecting provided, the magnetic sensor is characterized in that provided between the magnetism collecting parts facing each other in the radial direction.
[0012]
According to the torque sensor of the present invention, when a torsional torque is input between the first shaft and the second shaft and the elastic member is twisted, the relative position between the hard magnetic material and the soft magnetic material changes. The magnetic flux density generated in the magnetic circuit of the soft magnetic material changes. Further, the magnetic flux generated in the soft magnetic material is guided to the auxiliary soft magnetic material, and is collected in the magnetic flux collecting portion provided in the auxiliary soft magnetic material. Therefore, the torsion torque applied between the first axis and the second axis can be obtained by detecting the magnetic flux density generated in the auxiliary soft magnetic body via the magnetic flux collecting part by the magnetic sensor.
[0013]
According to this configuration, the magnetic flux generated from the hard magnetic material does not need to be directly detected by the magnetic sensor, so that the non-contact type magnetic sensor can be fixed and used at a fixed position. As a result, there is no need to provide an electrical contact portion for the magnetic sensor, so that a highly reliable torque sensor can be provided. Further, by collecting the magnetic flux generated in the auxiliary soft magnetic material in the magnetic flux collecting part, the average of the magnetic flux density generated in the entire circumference of the soft magnetic material can be detected by the magnetic sensor. As a result, it is possible to reduce a detection error due to manufacturing variations, assembly accuracy, center deviation, and the like of components constituting the magnetic circuit. In addition, by providing the magnetic sensor between the magnetic flux collecting portions facing each other in the radial direction, it is possible to suppress an increase in the size of the torque sensor in the radial direction.
[0014]
Further, in the torque sensor according to the third aspect, the auxiliary soft magnetic body is molded with a resin member so as to have an opening for inserting the magnetic sensor, and the magnetic sensor is inserted into the opening of the resin member. In this case, a guide portion is provided, and the guide portion is formed so as to expand toward the insertion side of the magnetic sensor.
[0015]
With this configuration, the magnetic sensor can be easily inserted into the opening.
[0016]
According to a fourth aspect, in the electric power steering apparatus having the torque sensor according to any one of the first to third aspects, a control for determining a steering assist torque for assisting the torsional torque from a magnetic flux density detected by the torque sensor. And a terminal of the magnetic sensor is electrically connected directly to a control board of the control unit.
[0017]
With this configuration, since the terminal of the magnetic sensor and the control board are directly connected, the distance between the magnetic sensor and the control board can be shortened. Furthermore, since it is not necessary to use a terminal such as an extension between the terminal of the magnetic sensor and the control board, an increase in the number of parts can be suppressed.
[0018]
According to a fifth aspect of the present invention, in the electric power steering apparatus according to the fourth aspect, the control board is provided orthogonal to the terminal of the magnetic sensor.
[0019]
With this configuration, it is possible to easily connect the terminal of the magnetic sensor to the control board. Further, since the terminals of the magnetic sensor up to the control board can be connected to the control board without bending, the number of assembling steps can be reduced.
[0020]
According to a sixth aspect of the present invention, in the method for manufacturing an electric power steering device according to the fourth or fifth aspect, a first step of inserting the magnetic sensor into the opening from the axial direction and providing the magnetic sensor so as to be movable in the axial direction. , A second step of fixing the control board, and a third step of electrically connecting the terminals of the magnetic sensor directly to the control board.
[0021]
With this configuration, the magnetic sensor is provided so as to be movable in the axial direction. For example, when a thermal expansion difference occurs in the axial direction, stress is generated in the solder connecting the terminal of the magnetic sensor and the control board. Can be suppressed.
[0022]
According to a seventh aspect, in the method for manufacturing an electric power steering device according to the fourth or fifth aspect, a first step of temporarily assembling a terminal of the magnetic sensor to the control board, and inserting the magnetic sensor into the opening from the axial direction. And a second step of fixing the control board and providing a third step of electrically directly connecting the terminals of the magnetic sensor to the control board. Features.
[0023]
With this configuration, the terminal of the magnetic sensor is connected to the control board by solder after the magnetic sensor is inserted into the opening from the axial direction and provided in a state in which the magnetic sensor can be moved in the axial direction, so that excessive stress is generated in the solder. Can be suppressed.
[0024]
According to an eighth aspect of the present invention, in the method for manufacturing an electric power steering device according to the fourth or fifth aspect, a first step of fixing the control board and a magnetic sensor having a terminal bent in an L shape are provided on the control board. A second step of inserting the insertion hole into the opening so as to be movable in the axial direction after passing through the insertion hole in the axial direction, and electrically connecting the distal end of the L-shaped terminal of the magnetic sensor to the control board. And a third step of direct connection.
[0025]
With this configuration, the terminal of the magnetic sensor is connected to the control board by solder after the magnetic sensor is inserted into the opening from the axial direction and provided in a state in which the magnetic sensor can be moved in the axial direction, so that excessive stress is generated in the solder. Can be suppressed. In addition, since the end of the terminal bent in an L shape is connected to the control board by soldering, the soldering area of the terminal can be increased. Thereby, the connection strength between the terminal and the control board can be increased.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments shown in the drawings will be described.
[0027]
[First Embodiment]
A first embodiment of the torque sensor 1 will be described.
[0028]
FIG. 1 is an exploded view of the torque sensor 1 of the present embodiment. FIG. 2 is an axial sectional view of the torque sensor 1 of the present embodiment. FIG. 3 is an axial plan view (a) and a side view (b) showing the positional relationship between the magnet 5 and a pair of magnetic yokes 6A and 6B. FIG. 4 is a graph showing the relationship between the torsion angle of the torsion bar 4 (the angle of deviation between the magnet 5 and the magnetic yoke 6) and the magnetic flux density generated in the magnetic yoke 6.
[0029]
The torque sensor 1 according to the present embodiment is used, for example, in an electric power steering device for a vehicle, and is provided between an input shaft 2 (first shaft) and an output shaft 3 (second shaft) that constitute a steering shaft. A torsion bar 4 (elastic member) for connecting the input shaft 2 and the output shaft 3 coaxially, a magnet 5 (hard magnetic material) attached to an end of the input shaft 2, and an end of the output shaft 3 A set of magnetic yoke 6 (soft magnetic material) to be attached, a set of magnetic flux collecting ring 7 (auxiliary soft magnetic material) arranged close to magnetic yoke 6, and guiding magnetic flux from magnetic yoke 6 And a magnetic sensor 8 for detecting a magnetic flux density generated between a pair of magnetic yokes 6 via a magnetic sensor 8.
[0030]
Both ends of the torsion bar 4 are fixed to the input shaft 2 and the output shaft 3 by pins 9, respectively, and have torsional / torque characteristics according to the purpose. Therefore, the input shaft 2 and the output shaft 3 can relatively rotate due to the torsion bar 4 being twisted.
[0031]
The magnet 5 is provided in a ring shape, and the S pole and the N pole are alternately magnetized in the circumferential direction, and are formed to have, for example, 24 poles.
[0032]
As shown in FIG. 1, the pair of magnetic yokes 6 (6A, 6B) is an annular body disposed close to the outer periphery of the magnet 5, and is a soft magnetic body made of, for example, a magnetic material made of iron. The same number (12) of claws 6a as the N pole and the S pole of the magnet 5 are provided at equal intervals on the entire circumference. The set of magnetic yokes 6 is positioned by the fixing portion 10 (see FIG. 2) such that the claws 6a are alternately arranged while being shifted in the circumferential direction.
[0033]
The pair of magnetic yokes 6 and the magnets 5 are applied to the respective magnetic yokes 6 in a state where the torsion bar 4 is not twisted (when no torsional torque is applied between the input shaft 2 and the output shaft 3). It is arranged so that the center of the provided claw 6a and the boundary between the N pole and the S pole of the magnet 5 coincide (see FIG. 3B).
[0034]
The set of magnetic flux collecting rings 7 (7A, 7B) is a soft magnetic material similar to the magnetic yoke 6, and is provided in a ring shape as shown in FIG. 2, and is provided near the outer periphery of the magnetic yokes 6A, 6B, respectively. It is arranged and molded by a resin member (not shown). One magnetic flux collection ring 7A is provided with a flat magnetic flux collection portion 7A1 at one location in the circumferential direction so as to radially face the other magnetic flux collection ring 7B.
[0035]
As shown in FIGS. 1 and 2, the magnetic sensor 8 is inserted between the magnetic flux collecting portion 7A1 and the other magnetic flux collecting ring 7B that are opposed in the radial direction, and the magnetic sensor 8 is connected between the magnetic flux collecting portion 7A1 and the other magnetic flux collecting ring 7B. The magnetic flux density generated between them is detected.
[0036]
As the magnetic sensor 8, for example, a Hall element, a Hall IC, a magnetic resistance element, or the like can be used, and the detected magnetic flux density is converted into an electric signal (for example, a voltage signal) and output.
[0037]
Next, the operation of the present embodiment will be described.
[0038]
In a state where no torsional torque is applied between the input shaft 2 and the output shaft 3, that is, in a neutral position where the torsion bar 4 is not twisted, as shown in FIG. The center of the provided claw 6a coincides with the boundary between the N pole and the S pole of the magnet 5. In this case, since the same number of magnetic lines of force enter and exit from the claws 6a of the magnetic yokes 6 from the N and S poles of the magnet 5, the magnetic lines of force are closed inside one magnetic yoke 6A and the other magnetic yoke 6B. No magnetic flux density is generated between the magnetic flux collecting portion 7A1 and the other magnetic flux collecting ring 7B, and the magnetic flux density detected by the magnetic sensor 8 becomes 0 (see FIG. 4).
[0039]
When a torsion torque is applied between the input shaft 2 and the output shaft 3 and the torsion bar 4 is twisted, a magnet 5 fixed to the input shaft 2 and a pair of magnetic yokes 6 fixed to the output shaft 3 Changes in the circumferential direction. As a result, as shown in FIG. 4A or 4C, the center of the claw 6a provided on the magnetic yoke 6 does not coincide with the boundary between the N pole and the S pole of the magnet 5, so that each magnetic yoke In 6, the number of lines of magnetic force having N or S polarity increases.
[0040]
At this time, the magnetic flux generated from the magnet 5 is guided to each magnetic flux collection ring 7 through each magnetic yoke 6, and is preferentially gathered at the magnetic flux collection part 7A1 provided on one magnetic flux collection ring 7A. Then, a magnetic flux density is generated between the magnetic flux collecting part 7A1 and the other magnetic flux collecting ring 7B. As shown in FIG. 4, the magnetic flux density is substantially proportional to the amount of twist of the torsion bar 4, and the polarity is reversed according to the direction of twist of the torsion bar 4. Then, the magnetic flux density can be detected by the magnetic sensor 8 and taken out as a voltage signal.
[0041]
[Effects of First Embodiment]
In the torque sensor 1 of the present embodiment, when the torsion bar 4 is twisted and the relative position between the magnet 5 and the set of magnetic yokes 6 changes in the circumferential direction, the magnetic flux generated from the magnet 5 passes through the magnetic yoke 6. The magnetic flux is guided to the magnetic flux collection ring 7 and preferentially gathers at the magnetic flux collection portion 7A1 provided on one magnetic flux collection ring 7A. Then, the magnetic flux density between the magnetic flux collecting portion 7A1 and the other magnetic flux collecting ring 7B changes. Therefore, by inserting the magnetic sensor 8 between the magnetic flux collecting portion 7A1 and the other magnetic flux collecting ring 7B that are opposed in the radial direction, the magnetic flux density between the magnetic flux collecting rings 7 can be detected. Accordingly, it is not necessary to provide an electrical contact portion (for example, a slip ring and a brush) to the magnetic sensor 8, so that a highly reliable torque sensor 1 can be provided. Further, by detecting the magnetic flux density generated between the magnetic flux collecting portion 7A1 and the other magnetic flux collecting ring 7B with the magnetic sensor 8, the average of the magnetic flux density generated over the entire circumference of the magnetic yoke 6 can be obtained. In addition, it is possible to suppress manufacturing errors and assembling accuracy of components constituting the magnetic circuit, and detection errors due to a center shift between the input side and the output side. Furthermore, by inserting the magnetic sensor between the magnetic flux collecting portion 7A1 and the other magnetic flux collecting ring 7B that face each other in the radial direction, it is possible to suppress the torque sensor 1 from being enlarged in the radial direction.
[0042]
A pair of magnets 5 fixed to the input shaft 2 and a pair of magnetic yokes 6 fixed to the output shaft 3 are provided with claws 6 a provided on each magnetic yoke 6 in a state where the torsion bar 4 is not twisted. And the boundary between the N pole and the S pole of the magnet 5 are arranged to coincide with each other. According to this configuration, as shown in FIG. 4, even when the strength of the magnet 5 fluctuates due to a temperature change, for example, the neutral point of the magnetic sensor 8 does not shift, so that the accuracy near the neutral point is stabilized. And can be less affected by offset drift.
[0043]
[Second embodiment]
Here, a second embodiment of the torque sensor 1 will be described.
[0044]
5 and 6 are views showing a modification of FIG.
[0045]
Although the magnetic flux collecting portion 7A1 in the first embodiment is provided only on one magnetic flux collecting ring 7A, in the present embodiment, as shown in FIG. 5, the magnetic flux collecting portion 7B1 is also provided on the other magnetic flux collecting ring 7B. Is provided. Since the magnetic sensor 8 is provided between the magnetic flux collecting portions 7A1 and 7B1, the gap between the magnetic flux collecting rings 7 of the magnetic sensor 8 can be reduced, so that variations in magnetic flux density can be reduced. Thus, the magnetic flux density can be accurately detected. Further, since the magnetic flux collecting sections 7A1 and 7B1 are provided on the control board 31 side, the distance between the magnetic sensor 8 provided between the magnetic flux collecting sections 7A1 and 7B1 and the control board 31 is increased. Can be shortened.
[0046]
Further, in FIG. 6, the magnetic flux collecting portion 7B1 is provided on the magnetic flux collecting portion 7A1 side, and the magnetic flux collecting portion 7A1 is provided on the outer diameter side of the magnetic flux collecting portion 7B1. With this configuration, the size of the magnetic flux collecting portion 7A1 and the size of the magnetic flux collecting portion 7B1 can be made substantially the same, so that the material of one magnetic flux collecting ring 7A and the other magnetic flux collecting ring 7B can be made common. .
[0047]
[Third embodiment]
Here, a third embodiment of the torque sensor 1 and an electric power steering device using the torque sensor 1 will be described.
[0048]
FIG. 7 is an axial sectional view along the input shaft and the output shaft of the electric power steering device. FIG. 8 is an enlarged view of a part of FIG. FIG. 9 is a diagram for explaining the manufacturing method (1). FIG. 10 is a diagram for explaining the manufacturing method (2). FIG. 11, FIG. 12, and FIG. 13 are views for explaining the manufacturing method (3).
[0049]
The electric power steering device is provided in the passenger compartment of the vehicle, and includes a torque sensor 1, a control unit 11, an electric motor 12, and a power transmission unit 13, as shown in FIG. The power transmission unit 13 is provided in the housing 14 and the cover 15, and the electric motor 12 is provided in the yoke 16.
The magnet 5 is press-fitted and fixed to the outer periphery of the input shaft 2 via a magnet fixing part 5a.
[0050]
The magnetic yoke 6 is molded by a resin member 61 and is press-fitted and fixed to the outer periphery of the output shaft 3 via a magnetic yoke fixing portion 6a.
[0051]
As shown in FIG. 7, the magnetic flux collecting ring 7 is molded by a resin member 71 so as to have an opening 71 a for inserting the magnetic sensor 8. It is fixed to the inner peripheral surface. A guide portion 71b for guiding the magnetic sensor 8 when it is inserted is provided at one axial end of the opening 71a on the insertion side of the magnetic sensor 8. The guide portion 71b is formed so as to gradually spread toward the insertion side of the magnetic sensor 8.
[0052]
The magnetic sensor 8 is inserted into the opening 71a from the axial direction between the magnetic flux collecting part 7A1 and the other magnetic flux collecting ring 7B. In the inserted state, the magnetic sensor 8 is provided movably in the axial direction. The terminal 8a of the magnetic sensor 8 extends along the axial direction of the steering shaft.
[0053]
The control unit 11 controls the duty of the current flowing to the electric motor 12 based on the torsional torque detected by the torque sensor 1.
[0054]
The control board 11a is provided with an element for duty-controlling the current flowing to the electric motor 12. The control board 11a is provided orthogonal to the terminal 8a of the magnetic sensor 8 and is supported by the cylindrical member 17. The terminal 8a of the magnetic sensor 8 is directly connected by solder, and the torsion detected by the torque sensor 1 is used. Torque is input.
[0055]
The electric motor 12 applies a steering assist torque to the output shaft 3 to assist the torsional torque of the steering determined by the control unit 11.
[0056]
The power transmission unit 13 transmits the steering assist torque output from the electric motor 12 to the steered wheels.
[0057]
The housing 14 is made of aluminum, and has a support member 17 fixed inside.
[0058]
The cover 15 is for closing an open end of the housing 14.
[0059]
The support member 17 has a shape combining a cylindrical shape and a rectangular parallelepiped shape, and is provided in the housing 14. The support member 17 supports the control board 11a on the surface on the steering side in the axial direction, and is fixed to the inner wall of the housing 14 on the surface on the side opposite to the steering.
[0060]
[Effects of Third Embodiment]
In the present embodiment, the magnetic flux collection ring is molded by the resin member 71 so as to have an opening 71a for inserting the magnetic sensor 8, and one end of the opening 71a in the axial direction on the insertion side of the magnetic sensor 8 is provided. A guide portion 71b is provided on the insertion side of the magnetic sensor 8 so as to gradually widen. With this configuration, the magnetic sensor 8 can be easily provided between the magnetic flux collecting portion 7A1 and the other magnetic flux collecting ring 7B by inserting the magnetic sensor 8 in the axial direction from the opening 71a.
[0061]
Further, by providing the magnetic sensor 8 between the magnetic flux collecting part 7A1 and the magnetic flux collecting ring 7B which are radially opposed to each other, and by providing the control board 11a orthogonal to the terminal 8a of the magnetic sensor 8, the control extending in the axial direction is achieved. The terminal 8a of the magnetic sensor 8 up to the substrate 31 can be directly connected to the control substrate 11a without bending. Thus, the terminal 8a of the magnetic sensor 8 can be shortened, and the assemblability can be improved. Furthermore, since the control board 11a is provided orthogonal to the terminal 8a (orthogonal to the steering shaft), the terminal 8a can be easily connected to the control board 11a.
[0062]
[Production method]
Next, a method for manufacturing the electric power steering device according to the present embodiment will be described.
[0063]
The method for manufacturing the electric power steering device according to the present embodiment includes, for example, the following three methods.
[0064]
[Production method (1)]
Manufacturing method (1) will be described with reference to FIG.
[0065]
In the first step, the magnetic sensor 8 is inserted in the axial direction from the opening 71a, and is provided between the magnetic flux collecting portion 7A1 facing the radial direction and the other magnetic flux collecting ring 7B. At this time, the magnetic sensor 8 is held in a state where it can be moved in the axial direction.
[0066]
In the second step, the control board 11a is provided perpendicular to the terminal 8a of the magnetic sensor 8 (perpendicular to the steering axis), and the terminal 8a is inserted through the control board 11a. Then, the control board 11a is fixed to the support member 17 with, for example, screws.
[0067]
In the third step, the terminal 8a of the magnetic sensor 8 is directly connected to the control board 8a by soldering.
[0068]
[Production method 2]
Manufacturing method (2) will be described with reference to FIG.
[0069]
In the first step, the terminal 8a of the magnetic sensor 8 is inserted through the control board 11a, and the terminal 8a is bent in the radial direction to temporarily mount the magnetic sensor 8 on the control board 11a.
[0070]
In the second step, the magnetic sensor 8 is inserted into the opening 71a in the axial direction, and the control board 11a is fixed to the cylindrical member 17 by, for example, screws. At this time, the magnetic sensor 8 is held in a state where it can be moved in the axial direction.
[0071]
In the third step, the terminal 8a of the magnetic sensor 8 is directly connected to the control board 8a by soldering.
[0072]
[Production method 3]
Manufacturing method (3) will be described with reference to FIGS.
[0073]
In the first step, the control board 11a is fixed to the cylindrical member 17 with, for example, screws.
[0074]
In the second step, the magnetic sensor 8 whose terminal 8a is bent in an L-shape is inserted into the insertion hole 11b of the control board 11a in the axial direction, and then inserted into the opening 71a in the axial direction. At this time, the magnetic sensor 8 is inserted until the tip of the terminal 8a contacts the surface of the control board 11a. Further, the magnetic sensor 8 is held so as to be movable in the axial direction.
[0075]
In the third step, the tip of the L-shaped terminal 8a is directly connected to the control board 8a by soldering.
[0076]
In the manufacturing methods (1) to (3), since the magnetic sensor 8 is held so as to be movable in the axial direction, when the thermal expansion difference occurs in the axial direction, for example, the terminal 8a of the magnetic sensor 8 is connected to the terminal 8a. It is possible to suppress the occurrence of stress in the solder connecting to the control board 11a.
[0077]
Further, in the manufacturing methods (1) to (3), after the magnetic sensor 8 is inserted and provided so as to be movable in the axial direction, the terminal 8a of the magnetic sensor 8 is connected to the control board 11a by soldering. The generation of excessive stress can be suppressed.
[0078]
Also, in the manufacturing method (2), by performing the first step in advance, the step of inserting the magnetic sensor 8 into the opening 71a and the step of fixing the control board 11a are performed in the same step. The number of steps can be reduced.
[0079]
Further, in the manufacturing method (3), even if the control board 11a is fixed, the magnetic sensor 8 can be provided between the magnetic flux collecting portion 7A1 facing the radial direction and the other magnetic flux collecting ring 7B.
[0080]
Further, in the manufacturing method (3), the tip of the terminal 8a bent into an L shape is in contact with the surface of the control board 11a, and the tip of the terminal 8a is connected to the control board 11a by soldering. Since the soldering area of the terminal 8a can be increased, the connection strength between the terminal 8a and the control board 11a can be increased.
[Brief description of the drawings]
FIG. 1 is an exploded view of a torque sensor according to an embodiment. (1st Embodiment)
FIG. 2 is an axial sectional view of the torque sensor according to the embodiment. (1st Embodiment)
FIG. 3 is an axial plan view (a) and a side view (b) showing a positional relationship between a magnet and a set of magnetic yokes. (1st Embodiment)
FIG. 4 is a graph showing a relationship between a torsion angle of a torsion bar (a deviation angle between a magnet and a magnetic yoke) and a magnetic flux density generated in the magnetic yoke. (1st Embodiment)
FIG. 5 is a diagram showing a modification of FIG. 2; (2nd Embodiment)
FIG. 6 is a diagram showing a modification of FIG. 2; (2nd Embodiment)
FIG. 7 is an axial sectional view along an input shaft and an output shaft of the electric power steering device. (Third embodiment)
FIG. 8 is an enlarged view of a part of FIG. 7; (Third embodiment)
FIG. 9 is a diagram for explaining the manufacturing method (1).
FIG. 10 is a diagram for explaining the manufacturing method (2).
FIG. 11 is a drawing for explaining the manufacturing method (3).
FIG. 12 is a drawing for explaining the manufacturing method (3).
FIG. 13 is a drawing for explaining the manufacturing method (3).
[Explanation of symbols]
1: Torque sensor,
2. Input axis (first axis),
3 output shaft 3 (second shaft),
4: Torsion bar (elastic member),
5 ... magnet (hard magnetic material),
6. Magnetic yoke (soft magnetic material),
7 ... magnetic flux collection ring (auxiliary soft magnetic material),
7A1, 7B1 ... magnetic flux collecting part,
8 ... magnetic sensor,
8a ... Terminal,
9 ... pin,
10 ... fixed part,
11a: Control board.

Claims (8)

An elastic member that connects a first shaft and a second shaft coaxially, and that receives a torsional torque between the first shaft and the second shaft and that twists around its own axis; When,
A hard magnetic body connected to the first shaft and forming a magnetic field around the first shaft;
The magnetic member is connected to the second shaft and arranged in a magnetic field formed by the hard magnetic material to form a magnetic circuit, and when the relative position with respect to the hard magnetic material changes due to the torsion of the elastic member, the magnetic force is reduced. A soft magnetic material having a structure in which the magnetic flux density generated in the circuit changes,
A set of auxiliary soft magnetic bodies arranged in close proximity to the soft magnetic body, and for guiding magnetic flux from the soft magnetic body;
A magnetic sensor that detects a magnetic flux density generated in the auxiliary soft magnetic material,
One auxiliary soft magnetic body is provided to face the other auxiliary soft magnetic body in the radial direction, and has a magnetic flux collecting part that collects the magnetic flux,
The torque sensor according to claim 1, wherein the magnetic sensor is provided between the magnetic flux collecting portion facing in the radial direction and the other auxiliary soft magnetic body. An elastic member that connects a first shaft and a second shaft coaxially, and that receives a torsional torque between the first shaft and the second shaft and that twists around its own axis; When,
A hard magnetic body connected to the first shaft and forming a magnetic field around the first shaft;
The magnetic member is connected to the second shaft and arranged in a magnetic field formed by the hard magnetic material to form a magnetic circuit, and when the relative position with respect to the hard magnetic material changes due to the torsion of the elastic member, the magnetic force is reduced. A soft magnetic material having a structure in which the magnetic flux density generated in the circuit changes,
A set of auxiliary soft magnetic bodies disposed in close proximity to the soft magnetic body, and guiding magnetic flux from the soft magnetic body, and having a magnetic flux collecting portion for collecting the magnetic flux;
A magnetic sensor that detects a magnetic flux density generated in the auxiliary soft magnetic body through the magnetic flux collection unit,
The magnetic flux collecting portion provided on one auxiliary soft magnetic material and the magnetic flux collecting portion provided on the other auxiliary soft magnetic material are provided to face each other in a radial direction,
The said magnetic sensor is provided between the said magnetic flux collection parts which oppose in the radial direction, The torque sensor characterized by the above-mentioned. The torque sensor according to claim 1 or 2,
The auxiliary soft magnetic body is molded with a resin member so as to have an opening for inserting the magnetic sensor,
A guide portion for inserting the magnetic sensor is provided in the opening of the resin member,
The said guide part is formed so that it may expand toward the insertion side of the said magnetic sensor, The torque sensor characterized by the above-mentioned. An electric power steering apparatus having the torque sensor according to claim 1,
A control unit that determines a steering assist torque that assists the torsion torque from the magnetic flux density detected by the torque sensor,
An electric power steering device, wherein a terminal of the magnetic sensor is electrically connected directly to a control board of the control unit. The electric power steering device according to claim 4,
The electric power steering device, wherein the control board is provided orthogonal to a terminal of the magnetic sensor. The method for manufacturing an electric power steering device according to claim 4 or 5,
A first step of inserting the magnetic sensor into the opening from the axial direction and providing the magnetic sensor in a state movable in the axial direction;
A second step of fixing the control board;
And a third step of electrically directly connecting the terminals of the magnetic sensor to the control board. The method for manufacturing an electric power steering device according to claim 4 or 5,
A first step of temporarily assembling the terminals of the magnetic sensor to the control board, inserting the magnetic sensor into the opening from the axial direction, and providing the magnetic sensor so as to be movable in the axial direction, and fixing the control board. A second step of:
And a third step of electrically directly connecting the terminals of the magnetic sensor to the control board. The method for manufacturing an electric power steering device according to claim 4 or 5,
A first step of fixing the control board;
A second step of inserting the magnetic sensor whose terminal is bent in an L-shape from an axial direction into an insertion hole provided in the control board, and then inserting the terminal into the opening so as to be movable in the axial direction;
A third step of electrically directly connecting a distal end of the L-shaped terminal of the magnetic sensor to the control board.

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