torque sensor

Abstract

In order to suppress the influence of an external magnetic field at the time of detecting a torque while suppressing an increase in manufacturing cost, a torque sensor (10) is provided with a housing (20) in which a stator (50) and a magnet (55) are arranged on the inner side, and a magnetic flux collecting assembly (40) having a magnetic flux collecting yoke (43) that detects a change in magnetic flux and a Hall IC (45), the housing (20) has a housing portion (25) that houses the magnetic flux collecting assembly (40), the magnetic flux collecting yoke (43) has a first magnetic flux collecting yoke (43a) and a second magnetic flux collecting yoke (43b) that sandwich the Hall IC (45) from both sides in the axial direction of a first pinion (88a), a magnetic shield cover (70) is installed in the housing portion (25), the magnetic shield cover (70) has a first shield portion (71) that covers the housing portion (25) from one side in the axial direction and a second shield portion (72) that covers the housing portion (25) from the other side in the axial direction.

Description

Technical Field

[0001] This disclosure relates to torque sensors. Background Technology

[0002] As an example of a torque sensor that detects the torque applied to a rotating body of a steering device, there exists a torque sensor that detects torque by detecting changes in magnetic field. For example, the sensor device described in Patent Document 1 includes: a permanent magnet fixed to an input shaft; two magnetic yokes fixed to an output shaft; two magnetic collecting rings that guide magnetic flux from the magnetic yokes; and a magnetic sensor that detects the magnetic flux guided by the magnetic collecting rings.

[0003] Furthermore, the sensor device described in Patent Document 1 includes: a magnetic shielding member that covers the magnetic collecting ring from the outer radial direction; and an external magnetic shielding member that is assembled on the outer surface of the housing housing the permanent magnet and the yoke, having a portion overlapping with the magnetic sensor. Thus, by utilizing the magnetic shielding member and the external magnetic shielding member to block magnetic noise transmitted to the magnetic sensor, the detection accuracy of the sensor is improved.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-135139 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, when a magnetic shield is configured to block magnetic noise transmitted to the magnetic collecting ring and suppress the influence of external magnetic fields, the magnetic shield needs to be disposed over a large area around the magnetic collecting ring, thus easily leading to a complex shape. In this case, manufacturing and installation of the magnetic shield become difficult, resulting in increased manufacturing costs. Therefore, it is difficult to suppress the influence of external magnetic fields during torque detection while simultaneously mitigating the increased manufacturing costs.

[0009] This disclosure was made in view of the above circumstances, and its purpose is to provide a torque sensor that can suppress the influence of an external magnetic field when detecting torque while suppressing the increase in manufacturing costs.

[0010] Solution for solving the problem

[0011] The torque sensor disclosed herein comprises: a stator fixed to a shaft; a cylindrical magnet disposed opposite to the stator; a housing having the shaft, the stator, and the magnet disposed inside; and a magnetic collecting assembly having a magnetic collecting yoke and a Hall element, the magnetic collecting yoke detecting changes in magnetic flux corresponding to changes in the relative position between the stator and the magnet, the Hall element converting the changes in magnetic flux detected by the magnetic collecting yoke into an electrical signal and outputting it; the housing having a receiving portion protruding radially outward from the shaft and accommodating the magnetic collecting assembly; the magnetic collecting yoke having a first magnetic collecting yoke and a second magnetic collecting yoke; with the magnetic collecting assembly accommodated in the receiving portion, the first magnetic collecting yoke and the second magnetic collecting yoke clamping the Hall element from both axial sides of the shaft; a magnetic shielding cover being mounted in the receiving portion, the magnetic shielding cover having a first shielding portion covering the receiving portion from one axial side and a second shielding portion covering the receiving portion from the other axial side.

[0012] According to this structure, even when a magnetic material is close to the housing containing the magnetic yoke and Hall element arranged inside, the external magnetic field from the magnetic material acting on the Hall element in the detection direction (axial direction) of the magnetic flux detected by the Hall element can be shielded by the magnetic shield. Therefore, when detecting changes in magnetic flux acting on the stator from the magnet using the magnetic yoke and Hall element, the influence of the external magnetic field can be suppressed, and the torque sensor can appropriately detect the steering torque. Furthermore, since the magnetic yoke and Hall element are housed within the housing, the magnetic shield does not need to be of a complex shape. By designing it to cover the housing from both sides in the axial direction, the external magnetic field from the magnetic material outside the torque sensor can be shielded relative to the magnetic yoke and Hall element. Thus, the magnetic shield can shield the external magnetic field without a complex shape, thereby reducing the cost of manufacturing the magnetic shield. As a result, the influence of the external magnetic field when detecting torque can be suppressed while minimizing the increase in manufacturing costs.

[0013] As a preferred embodiment, at least one of the first shielding portion and the second shielding portion is configured to overlap with the Hall element in the axial direction.

[0014] According to this structure, the magnetic shield can shield the external magnetic field acting on the Hall element in the detection direction (i.e., axial direction) by using the first and second shielding portions, which overlap with the Hall element. Therefore, when detecting changes in magnetic flux from the magnet acting on the stator using the Hall element, the magnetic shield can suppress the influence of the external magnetic field. Consequently, the influence of the external magnetic field can be suppressed when detecting torque.

[0015] As a preferred embodiment, the magnetic shield is mounted together with the magnetic collecting assembly in the receiving part using a fastening member that mounts the magnetic collecting assembly to the receiving part.

[0016] According to this structure, since the magnetic shielding cover is mounted together with the magnetic collecting assembly in the housing using fastening members, there is no need to redesign the components for mounting the magnetic shielding cover in the housing, thus reducing the number of parts. Furthermore, since the magnetic shielding cover is mounted together with the magnetic collecting assembly in the housing using fastening members, the number of steps involved in mounting the magnetic collecting assembly and the magnetic shielding cover in the housing can be reduced. As a result, it is possible to suppress increases in manufacturing costs.

[0017] As a preferred embodiment, the magnetic shield has a shield mounting portion mounted on the receiving portion from the outer side in the radial direction, and the magnetic collecting assembly has a flange portion mounted on the receiving portion from the outer side in the radial direction. The magnetic shield positions the flange portion of the magnetic collecting assembly between the shield mounting portion and the receiving portion and mounts it to the receiving portion using the fastening member.

[0018] According to this structure, since the magnetic shielding cover positions the flange of the magnetic collecting assembly between the shielding mounting part and the receiving part and is mounted to the receiving part using fastening members, the magnetic shielding cover and the magnetic collecting assembly can be mounted to the receiving part using shared fastening members. This reduces the number of components and the number of steps required to mount the magnetic collecting assembly and the magnetic shielding cover to the receiving part. As a result, it helps to suppress increases in manufacturing costs.

[0019] In a preferred embodiment, the magnetizing assembly has a connector portion that connects to an external connector, and the shielding mounting portion has a through hole through which the connector portion passes, with the connector portion passing through the through hole from the radially inner side toward the outer side.

[0020] According to this structure, the connector portion of the magnetic collecting assembly passes through the through hole of the shield mounting portion from the radially inner side to the outer side. Therefore, the shield mounting portion can connect to the external connector and shield the external magnetic field. Thus, while ensuring the electrical connection between the Hall element of the magnetic collecting assembly and the external control device, thus ensuring the torque detection path, the external magnetic field is shielded using the magnetic shield. As a result, steering torque can be properly detected, and the influence of the external magnetic field during torque detection can be suppressed.

[0021] In a preferred embodiment, the housing has a first housing and a second housing connected to each other, the first housing having the receiving portion, the first shielding portion covering the receiving portion in the axial direction from the side opposite to the side where the second housing is located, and the second shielding portion covering the receiving portion in the axial direction from the side where the second housing is located.

[0022] According to this structure, when the housing has a first housing with a receiving portion and a second housing connected to the first housing, the first shielding portion and the second shielding portion of the magnetic shield cover the receiving portion from opposite sides in the axial direction. Therefore, it is easy to obtain a structure that shields the Hall element from external magnetic fields relative to the magnetic yoke. As a result, it is possible to suppress the influence of external magnetic fields when detecting torque while suppressing the increase in manufacturing costs.

[0023] In a preferred embodiment, the receiving portion is disposed near the portion of the first housing that connects to the second housing, the radial diameter of the end of the second housing on the side that connects to the first housing is greater than the radial diameter of the portion of the first housing opposite to the side where the receiving portion is located on the second housing, and for the magnetic shield, the radial length of the second shield is shorter than the radial length of the first shield.

[0024] According to this structure, the radial length of the surface on the side where the second housing of the receiving portion is located is shorter than the radial length of the surface on the opposite side of the second housing. On the other hand, in the magnetic shield, the radial length of the second shield covering the surface on the side where the second housing of the receiving portion is located is shorter than the radial length of the first shield covering the surface on the opposite side of the second housing. Therefore, the magnetic shield can cover the receiving portions protruding radially from the housing on both sides with different axial protrusions from both sides over the largest possible range. Thus, the magnetic shield can shield the magnetic field acting on the inside of the receiving portion from a magnetic body that can approach the receiving portion protruding from the housing. As a result, the influence of external magnetic fields when detecting torque can be suppressed.

[0025] As a preferred embodiment, the receiving portion has an opening facing outward in the radial direction, and the magnetizing assembly is received in the receiving portion by being inserted into the inside of the receiving portion through the opening.

[0026] According to this structure, since the magnet collecting assembly is inserted into the inside of the receiving portion through the opening, it can be easily positioned inside the receiving portion. Consequently, the magnet collecting yoke and Hall element of the magnet collecting assembly can be easily positioned inside the receiving portion, and the magnet collecting yoke can be easily positioned relative to the stator in an appropriate position. As a result, steering torque can be appropriately detected, and the increase in manufacturing costs can be suppressed.

[0027] As a preferred embodiment, the magnetic collecting assembly includes a sensor housing, a circuit board on which the Hall element is disposed and the magnetic collecting yoke are mounted on the sensor housing, and an O-ring is disposed between the outer peripheral surface of the sensor housing and the inner peripheral surface of the receiving portion to abut against both.

[0028] According to this structure, since an O-ring is provided that abuts against both the outer peripheral surface of the sensor housing and the inner peripheral surface of the receiving part, it is possible to prevent water or the like from entering the receiving part. As a result, it is possible to suppress malfunctions of the Hall element caused by water or the like entering the receiving part, and to ensure durability.

[0029] As a preferred embodiment, the magnetizing assembly has a cover that covers the circuit board mounted on the sensor housing, and the O-ring is positioned radially outward from the position where the cover is positioned.

[0030] According to this structure, the circuit board can be sealed without placing a sealing member between the sensor housing and the cover, thus reducing the number of sealing members required to prevent water or other contaminants from entering the circuit board. This allows for a reduction in the number of components and also reduces the number of steps involved in assembling the magnetizing assembly into the housing. As a result, durability can be ensured while minimizing increases in manufacturing costs.

[0031] The effects of the invention

[0032] The torque sensor disclosed herein has the following effect: it can suppress the influence of external magnetic fields when detecting torque while suppressing the increase in manufacturing costs. Attached Figure Description

[0033] Figure 1 This is a schematic diagram illustrating the steering device used to explain the implementation method.

[0034] Figure 2 This is a cross-sectional view of the steering device according to the embodiment, at a section containing the torque sensor.

[0035] Figure 3 On the Zhou Xiang and Figure 2 Sectional views at different locations.

[0036] Figure 4 This is a schematic diagram illustrating the general structure of the magnet, stator, and magnetic yoke of a torque sensor.

[0037] Figure 5 yes Figure 2 A detailed diagram of the area surrounding the torque sensor is shown.

[0038] Figure 6 This is an exploded 3D view of the magnetic collection component.

[0039] Figure 7 This is an exploded side view of the magnetic assembly and magnetic shield.

[0040] Figure 8 This is a detailed diagram of the portion of the housing where the magnetic collecting assembly and magnetic shield are installed.

[0041] Figure 9 This indicates that the magnetic shielding cover will be installed on Figure 8 A detailed diagram showing the state prior to the first housing.

[0042] Figure 10 This indicates that the magnet collection assembly will be installed on Figure 9 A detailed diagram showing the state prior to the first housing. Detailed Implementation

[0043] The present disclosure will now be described in detail with reference to the accompanying drawings. Furthermore, the present disclosure is not limited to the methods of carrying out the invention described below (hereinafter referred to as embodiments). Additionally, the constituent elements in the following embodiments include elements readily conceived by those skilled in the art, substantially the same elements, and elements of so-called equivalent scope. Moreover, the constituent elements disclosed in the following embodiments can be appropriately combined.

[0044] [Implementation Method]

[0045] Figure 1 This is a schematic diagram illustrating the steering device 80 of the embodiment. (As shown) Figure 1 As shown, the steering system 80 includes a steering wheel 81, a steering shaft 82, a universal joint 84, an intermediate shaft 85, a universal joint 86, a short shaft 87, a steering gear 88, and a tie rod 89, in the order of force transmission from the operator. Additionally, the steering system 80 includes a control unit (hereinafter referred to as an ECU (Electronic Control Unit)) 100, a torque sensor 10, and an electric motor 102. The vehicle speed sensor 101 is installed in the vehicle and outputs a vehicle speed signal V to the ECU 100 via CAN (Controller Area Network) communication.

[0046] The steering shaft 82 is connected to the steering wheel 81 at one end and to the universal joint 84 at the other end.

[0047] The intermediate shaft 85 is connected to the universal joint 84 at one end and to the universal joint 86 at the other end. The short shaft 87 is connected to the universal joint 86 at one end and to the torque sensor 10 at the other end. The torque sensor 10 is connected to the short shaft 87 at one end and to the first pinion 88a of the steering gear 88 at the other end.

[0048] In detail, the first pinion 88a is a shaft-shaped member with teeth (not shown) formed at the end opposite to the side connected to the short shaft 87, which mesh with the rack 88b described later. The short shaft 87 and the first pinion 88a are connected via a torsion bar 87a (see reference). Figure 2The torsion bar 87a is connected to the short shaft 87 at one end and to the first pinion 88a at the other end. The torsion bar 87a transmits rotational torque between the short shaft 87 and the first pinion 88a.

[0049] The torque sensor 10 is a torque detection device that detects the torque acting on the shaft connected to the torque sensor 10, and detects the rotational torque transmitted between the short shaft 87 and the first pinion 88a via the torsion bar 87a. That is, the short shaft 87 and the first pinion 88a connected via the torsion bar 87a are the shafts that are detected when the torque is detected by the torque sensor 10.

[0050] The steering gear 88 includes a first pinion 88a, a rack 88b, and a second pinion 88c. The first pinion 88a is connected to a short shaft 87 via a torsion bar 87a. In the rack 88b, rack teeth (not shown) mesh with the teeth of the first pinion 88a. Furthermore, the rack 88b meshes with the second pinion 88c at a different position than the first pinion 88a.

[0051] An electric motor 102 is connected to the second pinion 88c via a worm gear reducer (not shown). The second pinion 88c can rotate using the driving force transmitted from the electric motor 102. The electric motor 102 rotates the second pinion 88c via the worm gear reducer (not shown). The electric motor 102 is, for example, a brushless motor, but it can also be a motor with brushes (slider elements) and a commutator (rectifier).

[0052] The steering gear 88 converts the rotational motion transmitted to the first pinion 88a and the second pinion 88c into linear motion using the rack 88b disposed inside the rack housing 90. In this embodiment, the steering device 80 is a double-pinion assisted type where the rack 88b uses the rotational motion transmitted from the first pinion 88a and the second pinion 88c to perform linear motion. The tie rod 89 is connected to the rack 88b. That is, the steering device 80 is a rack-and-pinion type electric power steering device.

[0053] The torque sensor 10 detects the steering force transmitted by the driver to the steering shaft 82 via the steering wheel 81 as steering torque. The vehicle speed sensor 101 detects the vehicle speed (vehicle speed) of the vehicle equipped with the steering system 80. The electric motor 102, torque sensor 10, and vehicle speed sensor 101 are electrically connected to the ECU 100.

[0054] The ECU 100 controls the operation of the electric motor 102. Additionally, the ECU 100 acquires signals from the torque sensor 10 and the vehicle speed sensor 101, respectively. Specifically, the ECU 100 acquires the steering torque T from the torque sensor 10 and the vehicle speed signal V from the vehicle speed sensor 101. The ECU 100 is powered by a power source (e.g., the vehicle's battery) 104 when the ignition switch 103 is on. The ECU 100 calculates an auxiliary steering command value based on the steering torque T and the vehicle speed signal V. Then, the ECU 100 adjusts the power supply value X to the electric motor 102 based on this calculated auxiliary steering command value. The ECU 100 acquires information about the induced voltage from the electric motor 102 or information output from a rotation detection device such as a rotary transformer installed on the electric motor 102 as operation information Y.

[0055] The steering force input by the operator (driver) to the steering wheel 81 is transmitted to the first pinion 88a. The steering force transmitted to the first pinion 88a is transmitted to the tie rod 89 via the steering gear 88, causing the wheels to shift.

[0056] Additionally, the steering force input by the operator to the steering wheel 81 is transmitted to the torque sensor 10, which is positioned along the steering force transmission path from the steering wheel 81 to the first pinion 88a. At this time, the ECU 100 obtains the steering torque T from the torque sensor 10 and the vehicle speed signal V from the vehicle speed sensor 101. Furthermore, the ECU 100 controls the operation of the electric motor 102. The auxiliary steering torque generated by the electric motor 102 is transmitted to the second pinion 88c.

[0057] The auxiliary steering torque transmitted to the second pinion 88c is transmitted to the tie rod 89 via the steering gear 88, causing the wheels to shift. That is, in addition to the steering force of the operator transmitted to the rack 88b via the first pinion 88a, the steering device 80 also uses the auxiliary steering torque of the electric motor 102 transmitted to the rack 88b via the second pinion 88c to shift the wheels.

[0058] like Figure 1 As shown, the steering device 80 is a double-pinion type that applies auxiliary force to the second pinion 88c, but it is not limited to this. The steering device 80 may also be, for example, a steering column-assisted type that applies auxiliary force to the steering shaft 82, or a single-pinion-assisted type that applies auxiliary force to the first pinion 88a, which are types of electric power steering devices. Alternatively, it may be a rack-assisted type electric power steering device that applies auxiliary force to the rack 88b without using pinions, such as a ball screw type that uses a ball screw to apply auxiliary force to the rack 88b.

[0059] Figure 2 This is a cross-sectional view of the steering device according to the embodiment, at a section including the torque sensor 10. Figure 3On the Zhou Xiang and Figure 2 Cross-sectional views at different locations. Furthermore, in the following description, unless otherwise specified regarding direction, the axial direction of the short shaft 87 and the first pinion 88a, where the torque sensor 10 is located, will also be described as the axial direction in the torque sensor 10. Similarly, the circumferential direction centered on the axis of the short shaft 87 and the first pinion 88a will also be described as the circumferential direction in the torque sensor 10, and the radial direction centered on the axis of the short shaft 87 and the first pinion 88a will also be described as the radial direction in the torque sensor 10.

[0060] A housing 20 is disposed around the portion of the short shaft 87 and the first pinion 88a connected by a torsion bar 87a. The housing 20 has a first housing 21 and a second housing 31 interconnected. The first housing 21 is axially positioned near the short shaft 87 and primarily covers the short shaft 87, while the second housing 31 is axially positioned near the first pinion 88a and primarily covers the first pinion 88a. In other words, the short shaft 87 and the first pinion 88a are at least partially disposed inside the first housing 21 and the second housing 31, with at least a partial portion of the short shaft 87 disposed inside the first housing 21 and at least a partial portion of the first pinion 88a disposed inside the second housing 31. The first housing 21 is mounted to the second housing 31 using mounting bolts 37, thereby fixing the first housing 21 to the second housing 31.

[0061] Additionally, a bearing (not shown) is disposed inside the first housing 21, and the short shaft 87 is rotatably supported on the first housing 21 by means of the bearing disposed inside the first housing 21. Furthermore, a bearing (not shown) is also disposed inside the second housing 31, and the first pinion 88a is rotatably supported on the second housing 31 by means of the bearing disposed inside the second housing 31.

[0062] Since the short shaft 87 is rotatably supported on the first housing 21 and the first pinion 88a is rotatably supported on the second housing 31, the short shaft 87 and the first pinion 88a connected by the torsion bar 87a become a single unit and are rotatably supported on the first housing 21 and the second housing 31.

[0063] The housing 20 is mounted on the vehicle body in a state in which it cannot rotate relative to the vehicle body. The housing 20 supports the short shaft 87 and the first pinion 88a in a rotatable manner by means of bearings configured in the first housing 21 and bearings configured in the second housing 31.

[0064] The torque sensor 10 is disposed within the first housing 21, near the end of a short shaft 87 (serving as a first shaft) and a first pinion 88a (serving as a second shaft), which is connected to the short shaft 87 via a torsion bar 87a. Both the short shaft 87 and the first pinion 88a are shafts with hollow portions, with the end of one shaft entering the inner side of the other shaft from the end of the other. In this embodiment, the short shaft 87 enters the inner side of the first pinion 88a.

[0065] A torsion bar 87a is positioned inside the short shaft 87 and inside the first pinion 88a, with one end connected to the short shaft 87 and the other end connected to the first pinion 88a. That is, the short shaft 87 and the first pinion 88a are not directly connected, but rather connected via a shaft-like component, the torsion bar 87a. Therefore, the short shaft 87 and the first pinion 88a can rotate relative to each other. When the torsion bar 87a is torn, the short shaft 87 and the first pinion 88a rotate relative to each other as the torsion bar 87a twists.

[0066] The torque sensor 10 is disposed near the end of the short shaft 87 and the first pinion 88a connected by the torsion bar 87a. By detecting the angle of relative rotation between the short shaft 87 and the first pinion 88a, the torque acting between the short shaft 87 and the first pinion 88a can be detected.

[0067] The torque sensor 10 has a magnet 55 and a stator 50 (see reference). Figure 4 ) and magnetic yoke 43 (refer to Figure 4 Magnet 55 and stator 50 are respectively mounted on short shaft 87 and first pinion 88a. Magnetizing yoke 43 is mounted on sensor housing 41 of magnetizing assembly 40, thus magnetizing yoke 43 is included in magnetizing assembly 40. Magnetizing yoke 43 is fixed to first housing 21 by being mounted on first housing 21 via magnetizing assembly 40.

[0068] The magnetizing assembly 40 is housed in a housing portion 25 of the first housing 21. The housing portion 25 is disposed near the portion of the first housing 21 that connects to the second housing 31, and protrudes radially outward from the outer periphery of the first housing 21. The housing portion 25 of the first housing 21 has a space formed inside the housing portion 25 that communicates with the inside of the first housing 21, and the magnetizing assembly 40 is housed in the housing portion 25 by being disposed inside the housing portion 25 thus formed.

[0069] Furthermore, a magnetic shield 70 is installed in the receiving portion 25 of the first housing 21. The magnetic shield 70 is formed by bending a metal plate member. The magnetic shield 70 covers both axial sides of the receiving portion 25. Specifically, the portions of the magnetic shield 70 on both axial sides of the receiving portion 25 extend radially inward from a position close to the radially outer side of the receiving portion 25. Thus, the magnetic shield 70 extending radially covers both axial sides of the receiving portion 25.

[0070] The torque sensor 10 configured in this way can detect torque based on the change in magnetism when the short shaft 87 and the first pinion 88a rotate relative to each other due to the torsion of the torsion bar 87a.

[0071] Figure 4 This is a schematic diagram illustrating the general structure of the magnet 55, stator 50, and magnetic yoke 43 of the torque sensor 10. One of the magnet 55 and stator 50 of the torque sensor 10 is mounted on a first shaft, and the other is mounted on a second shaft. In this embodiment, the magnet 55 is mounted on a short shaft 87, which serves as the first shaft, and the stator 50 is mounted on a first pinion 88a, which serves as the second shaft. The magnet 55 is formed in a generally cylindrical shape, becoming a multipole magnet with multiple N poles and multiple S poles alternately arranged in the circumferential direction.

[0072] The stator 50 has a flange portion 51 and teeth 52. The flange portion 51 is formed into an annular plate shape with its thickness direction axial. The teeth 52 extend from the inner circumference of the annular flange portion 51 toward the axial direction of the flange portion 51 and are formed into a plate shape with its thickness direction radial to that of the flange portion 51. In addition, as teeth 52, a plurality of teeth 52 are arranged in a circumferential direction of the flange portion 51 with spacing between them.

[0073] The stator 50 thus formed comprises a pair of stators 50 with identical shapes, namely a first stator 50a and a second stator 50b, both of which have flange portions 51 and teeth 52. Specifically, the first stator 50a has an annular first flange portion 51a and a plurality of first teeth 52a, and the second stator 50b has an annular second flange portion 51b and a plurality of second teeth 52b. The first stator 50a and the second stator 50b are mounted on the same shaft with their flange portions 51 coaxial and oriented away from the other stator 50. In this embodiment, both the first stator 50a and the second stator 50b are mounted on a first pinion 88a.

[0074] In other words, the first stator 50a is configured such that the first tooth 52a extends from the first flange 51a toward the second stator 50b, and the second stator 50b is configured such that the second tooth 52b extends from the second flange 51b toward the first stator 50a. Since multiple first teeth 52a and second teeth 52b are provided at intervals in the first flange 51a and the second flange 51b, the first stator 50a and the second stator 50b are combined such that the teeth 52 of their own stators 50 are located in the circumferential direction in the portion where the teeth 52 of the other stator 50 are not present.

[0075] The magnet 55, mounted on the short shaft 87, is disposed inside the first stator 50a and the second stator 50b in this combination. Furthermore, the magnet 55 and the stator 50 are arranged with their axial directions aligned with the short shaft 87 and the first pinion 88a. Therefore, the magnet 55 and the stator 50 are mounted on the short shaft 87 and the first pinion 88a in a positional relationship where the outer peripheral surface of the magnet 55 is opposite to the teeth 52 of the stator 50. Because the magnet 55 and the stator 50 are arranged in the aforementioned positional relationship, when the short shaft 87 and the first pinion 88a rotate slightly relative to each other due to the torque transmitted between them via the torsion bar 87a, the magnetic flux acting on the stator 50 from the magnet 55 changes as the relative positional relationship between the magnet 55 and the stator 50 changes.

[0076] Additionally, a magnetic yoke 43, part of the magnetic collecting assembly 40, is disposed near the stator 50. The magnetic yoke 43 is a component used to detect changes in magnetic flux exerted on the stator 50 by the magnet 55, and is disposed near the flange portion 51 of the stator 50. Since a pair of stators, first stator 50a and second stator 50b, are provided as stator 50, a pair of magnetic yokes, first magnetic yoke 43a and second magnetic yoke 43b, are also provided accordingly. That is, as magnetic yokes 43, the first magnetic yoke 43a is disposed near the first flange portion 51a of the first stator 50a, and the second magnetic yoke 43b is disposed near the second flange portion 51b of the second stator 50b.

[0077] A pair of magnetic yokes 43 are located between the two flanges 51 of the stator 50, overlapping the flanges 51 of the stator 50 with a gap in the axial direction. Specifically, the first magnetic yoke 43a is positioned near the face of the first flange 51a where the second flange 51b is located, and the second magnetic yoke 43b is positioned near the face of the second flange 51b where the first flange 51a is located. These magnetic yokes 43 overlap the flanges 51 of the stator 50 within a predetermined range in the circumferential direction. That is, the portions of the first and second magnetic yokes 43a and 43b that overlap with the flanges 51 of the stator 50 are formed in a generally fan shape (see reference). Figure 6 Thus, the first magnetic yoke 43a and the second magnetic yoke 43b are configured to overlap with the flange 51 of the stator 50 within a portion of the circumferential direction.

[0078] Thus, by positioning the magnetic yoke 43 near the flange portion 51, the magnetic yoke 43 can detect changes in magnetic flux corresponding to changes in the relative position between the stator 50 and the magnet 55. In other words, the magnetic yoke 43 can detect changes in magnetic flux acting on the stator 50 from the magnet 55 when the short shaft 87 rotates slightly relative to the first pinion 88a.

[0079] Furthermore, a Hall IC 45 is disposed between the two magnetic yokes 43. The Hall IC 45 is positioned between the magnetic yokes 43 at a location near the flange 51 of the stator 50, away from the magnetic yokes 43. That is, the Hall IC 45 is sandwiched between the first magnetic yoke 43a and the second magnetic yoke 43b of the magnetic yokes 43. The Hall IC 45 has: a Hall element (not shown) that detects the change in magnetic flux detected by the magnetic yokes 43; and an output circuit (not shown) that converts the output voltage from the Hall element according to the change in magnetic flux into a digital electrical signal. Thus, the Hall IC 45 can detect the change in magnetic flux density acting on the two magnetic yokes 43, convert the detected change in magnetic flux density into an electrical signal, and output it as an electrical signal. In addition, a magnetic sensor employing the magnetoresistive effect or tunneling magnetoresistive effect can be used instead of the Hall IC. In short, it is acceptable as long as the change in magnetic flux density generated between the magnetic yokes 43 can be output as an electrical signal.

[0080] Figure 5 yes Figure 2 A detailed view of the area surrounding the torque sensor 10 is shown. The magnet 55 is mounted to the short shaft 87 using a first sleeve 56. The first sleeve 56 is a cylindrical component, and is mounted to the short shaft 87 by pressing the short shaft 87 into the first sleeve 56. The magnet 55 is fixed to the outer circumferential surface of the first sleeve 56, for example, using an adhesive, thereby allowing the magnet 55 to rotate integrally with the short shaft 87.

[0081] The stator 50 is mounted to the first pinion 88a using a second sleeve 53 and a carrier 54. The second sleeve 53 is a cylindrical component, and is mounted to the first pinion 88a by pressing the first pinion 88a into the second sleeve 53. The carrier 54 is a cylindrical component, integrally formed with the second sleeve 53 by injection molding. Therefore, the carrier 54 is mounted to the first pinion 88a via the second sleeve 53, and thus the carrier 54 is also mounted to the first pinion 88a together with the second sleeve 53.

[0082] The carrier 54, which is mounted on the first pinion 88a using the second sleeve 53, is positioned on the side facing the short shaft 87 from the first pinion 88a and on the outer side of the short shaft 87 in the radial direction. Furthermore, the carrier 54 is axially positioned at the same location as the magnet 55 and radially outward from the magnet 55.

[0083] The stator 50 is mounted on a carrier 54 configured as follows. Specifically, the first stator 50a and the second stator 50b are mounted on the carrier 54 with their teeth 52 located radially inside the carrier 54 and their flanges 51 protruding radially from the inner side of the carrier 54 toward the outer side. Thus, the first stator 50a and the second stator 50b, as a pair of stators 50, are both axially positioned at the same location as the magnet 55, and radially positioned outward from the magnet 55.

[0084] Furthermore, since the first stator 50a and the second stator 50b are mounted on a carrier 54 integrally formed with the second sleeve 53 mounted on the first pinion 88a, they can rotate integrally with the first pinion 88a. In other words, the stator 50, configured to rotate integrally with the first pinion 88a, is fixed to the first pinion 88a and has a flange portion 51 protruding radially outward from the first pinion 88a.

[0085] Thus, the magnet 55 is fixed to the short shaft 87, and the stator 50 is fixed to the first pinion 88a. As a result, the magnet 55 and the stator 50 are arranged together with the short shaft 87 and the first pinion 88a on the inner side of the housing 20.

[0086] The second housing 31 has a fitting recess 32 formed on its inner surface at the end near the side connected to the first housing 21 in the axial direction. The fitting recess 32 is a recess into which the fitting protrusion 22 of the first housing 21 enters.

[0087] A fitting recess 32 is formed on the end side of the first housing 21 that is configured with the second housing 31. A fitting protrusion 22 is formed on the first housing 21, which is fixed to the second housing 31, and enters the fitting recess 32. The fitting protrusion 22 is formed to protrude axially from the side of the first housing 21 toward the side where the second housing 31 is located. The fitting protrusion 22 enters the fitting recess 32, thereby positioning the first housing 21 radially relative to the second housing 31.

[0088] The fitting protrusion 22 is cylindrical and protrudes from the first housing 21, with an outer diameter slightly smaller than the inner diameter of the fitting recess 32. A groove is formed on the outer peripheral surface of the fitting protrusion 22 for the O-ring 23, which serves as a sealing member, to be inserted. The fitting protrusion 22 enters the fitting recess 32 when the O-ring 23 is inserted into the groove. Thus, with the fitting protrusion 22 inserted into the fitting recess 32, the O-ring 23 ensures a tight seal between the first housing 21 and the second housing 31.

[0089] With the first housing 21 and the second housing 31 in the state where the fitting protrusion 22 of the first housing 21 enters the fitting recess 32 of the second housing 31, the first housing 21 is installed on the second housing 31 by means of the mounting bolt 37, thereby connecting the first housing 21 and the second housing 31.

[0090] The magnetic collecting assembly 40, housed in the receiving portion 25 formed in the first housing 21, is mounted in the receiving portion 25 with the Hall IC 45 clamped inward from both sides in the axial direction by means of the first magnetic collecting yoke 43a and the second magnetic collecting yoke 43b while housed in the receiving portion 25. Specifically, the Hall IC 45 is disposed on the circuit board 44 of the magnetic collecting assembly 40, and the circuit board 44 is mounted on the sensor housing 41 of the magnetic collecting assembly 40.

[0091] Furthermore, the magnetic yoke 43 is mounted on the sensor housing 41 with the first magnetic yoke 43a and the second magnetic yoke 43b clamping the Hall IC 45 from both sides in the thickness direction of the circuit board 44. In this embodiment, the first magnetic yoke 43a is located axially on the side where the short shaft 87 is located, and the second magnetic yoke 43b is located axially on the side where the first pinion 88a is located. The magnetic collection assembly 40 is housed in the housing portion 25 with the thickness direction of the circuit board 44 on which the Hall IC 45 is disposed being axial. Thus, with the magnetic collection assembly 40 housed in the housing portion 25, the first magnetic yoke 43a and the second magnetic yoke 43b clamp the Hall IC 45 from both sides in the axial direction.

[0092] Furthermore, the axial position of the receiving portion 25 of the first housing 21 is close to the axial position of the magnet 55 and stator 50, which are fixed to the short shaft 87 and the first pinion 88a and disposed within the housing 20, and the receiving portion 25 protrudes radially outward. Thus, with the magnet collecting assembly 40 housed in the receiving portion 25, the first magnet collecting yoke 43a and the second magnet collecting yoke 43b of the magnet collecting assembly 40 can be disposed between the first flange portion 51a of the first stator 50a and the second flange portion 51b of the second stator 50b, which are fixed to the first pinion 88a.

[0093] The magnetizing assembly 40 housed in the housing portion 25 has a cover portion 42. The cover portion 42 is a member that covers the circuit board 44 mounted on the sensor housing 41. The magnetizing assembly 40 has: a first cover portion 42a, which is disposed on the opposite side of the side where the second housing 31 is located in the axial direction relative to the circuit board 44 and covers the circuit board 44; and a second cover portion 42b, which is disposed on the side where the second housing 31 is located in the axial direction relative to the circuit board 44 and covers the circuit board 44.

[0094] Additionally, an O-ring 47 is provided between the outer peripheral surface of the sensor housing 41 of the magnetic collecting assembly 40 housed in the housing section 25 and the inner peripheral surface of the housing section 25, to abut against both. The O-ring 47 is positioned radially outward from the position of the cover section 42.

[0095] In detail, a stepped portion 41d is formed on the outer peripheral surface of the sensor housing 41 of the magnetic collecting assembly 40, on the portion radially outer of the housing 42. The stepped portion 41d is formed one level lower than the portion located radially outer of the housing 41d. That is, the stepped portion 41d is formed as a notch-like shape formed by cutting a notch around the outer peripheral surface of the sensor housing 41. The inner peripheral surface of the O-ring 47 abuts against the sensor housing 41 by inserting into the stepped portion 41d of the sensor housing 41, and the outer peripheral surface abuts against the inner peripheral surface of the receiving portion 25. Thus, the O-ring 47 abuts against both the outer peripheral surface of the sensor housing 41 and the inner peripheral surface of the receiving portion 25.

[0096] The magnetic shield 70 mounted on the receiving portion 25 of the first housing 21 has a first shield 71 and a second shield 72. The first shield 71 covers a portion of the receiving portion 25 from one axial direction. The second shield 72 covers a portion of the receiving portion 25 from the other axial direction. Thus, both axial directions of the receiving portion 25 housing the magnetic collecting assembly 40 are covered by the magnetic shield 70 mounted on the receiving portion 25. In this embodiment, the first shield 71 covers the receiving portion 25 axially from the side opposite to where the second housing 31 is located, and the second shield 72 covers the receiving portion 25 axially from the side where the second housing 31 is located.

[0097] At least one of the first shielding portion 71 and the second shielding portion 72 of the magnetic shielding cover 70 is arranged axially overlapping with the Hall IC 45 of the magnetic collecting assembly 40 housed by the receiving portion 25. In this embodiment, the first shielding portion 71 of the first shielding portion 71 and the second shielding portion 72, which covers the receiving portion 25 from the side opposite to where the second housing 31 is located, is arranged axially overlapping with the Hall IC 45 of the magnetic collecting assembly 40. Specifically, the radial diameter of the end of the second housing 31 connected to the first housing 21 is greater than the radial diameter of the portion of the first housing 21 that is axially opposite to the side where the receiving portion 25 is located. In addition, in the first housing 21, the radial diameter of the portion axially closer to the side where the fitting protrusion 22 is located than the receiving portion 25 is greater than the radial diameter of the portion axially opposite to the side where the fitting protrusion 22 is located.

[0098] Therefore, in the receiving portion 25 located near the portion of the first housing 21 that connects to the second housing 31, the portion protruding radially from the outer peripheral surface of the first housing 21 is smaller on the axial side facing the second housing 31 compared to the portion on the opposite side facing the second housing 31. In other words, in the receiving portion 25, the radial length of the surface facing the second housing 31 is shorter than the radial length of the surface on the opposite side facing the second housing 31. Consequently, in the magnetic shielding cover 70 covering the receiving portion 25 on both sides axially, the radial length of the second shielding portion 72 is shorter than the radial length of the first shielding portion 71.

[0099] In other words, the first shielding portion 71 extends from near the radially outer end of the receiving portion 25 to near the outer peripheral surface of the first housing 21, and the second shielding portion 72 extends from near the radially outer end of the receiving portion 25 to near the outer peripheral surface of the second housing 31. Therefore, the second shielding portion 72, which covers the axially opposite sides of the receiving portion 25 and has a relatively shorter radial length, has a shorter radial length than the first shielding portion 71, which covers the opposite side of the second housing 31.

[0100] Next, the structure of the magnetizing assembly 40 will be explained. Figure 6 This is an exploded perspective view of the magnetic collection component 40. Figure 7 This is an exploded side view of the magnetic assembly 40 and the magnetic shielding cover 70. Furthermore, Figure 6 Viewed from the opposite side along the axial direction to illustrate the circuit board 44 Figure 5 The following Figures 8-10The diagram shows a perspective view of the magnetic collecting assembly 40. The magnetic collecting assembly 40 includes a sensor housing 41, a cover 42, a magnetic collecting yoke 43, a circuit board 44, and a connection terminal 46.

[0101] The sensor housing 41 has a flange portion 41a, a connector portion 41b, and a substrate mounting portion 41c. The flange portion 41a is for mounting the magnetic collecting assembly 40 radially outward to the receiving portion 25. The flange portion 41a is a plate-shaped member formed radially in the thickness direction. A bushing insertion hole 41aa is formed in the flange portion 41a, extending along the thickness direction of the flange portion 41a and for mounting a bushing 48. The bushing insertion hole 41aa is formed in the two threaded holes 27 (described later) formed in the receiving portion 25 (see reference). Figure 10 The two corresponding positions. The bushing 48, which is disposed in the bushing insertion hole 41aa, is a component made of metal material and formed into a generally cylindrical shape. It is inserted into the bushing insertion hole 41aa and held by the bushing insertion hole 41aa.

[0102] The connector portion 41b and the substrate mounting portion 41c are disposed opposite to each other in the thickness direction of the plate-shaped flange portion 41a. The connector portion 41b is the portion that connects to an external connector (not shown) for outputting an electrical signal from the torque sensor 10 to the outside. The connector portion 41b is disposed between two bushing insertion holes 41aa formed in the flange portion 41a, and protrudes radially outward from the flange portion 41a, that is, on the opposite side of the substrate mounting portion 41c in the thickness direction of the flange portion 41a.

[0103] The substrate mounting portion 41c is formed into a frame shape that is approximately rectangular when viewed along the axial direction, and the circuit board 44 is disposed inside the frame-shaped substrate mounting portion 41c. The first magnetic yoke 43a and the second magnetic yoke 43b of the magnetic yoke 43 are arranged axially on both sides of the circuit board 44 disposed in the substrate mounting portion 41c. The first magnetic yoke 43a and the second magnetic yoke 43b disposed on both sides of the circuit board 44 are respectively mounted in the substrate mounting portion 41c in a state that clamps the circuit board 44 from both sides.

[0104] The cover portion 42 is a component that covers the circuit board 44 mounted on the sensor housing 41 by sealing off the frame-shaped substrate arrangement portion 41c from both sides in the axial direction. It has a first cover portion 42a and a second cover portion 42b. The first cover portion 42a is disposed on the side of the substrate arrangement portion 41c where the first magnetic yoke 43a is disposed and is mounted on the substrate arrangement portion 41c. The second cover portion 42b is disposed on the side of the substrate arrangement portion 41c where the second magnetic yoke 43b is disposed and is mounted on the substrate arrangement portion 41c. Thus, the substrate arrangement portion 41c, which is frame-shaped and has the circuit board 44 and the magnetic yoke 43 disposed thereon, is sealed off from both sides in the axial direction by the first cover portion 42a and the second cover portion 42b.

[0105] Furthermore, a connection terminal 46 for electrical connection with an external connector is disposed in the connector portion 41b of the sensor housing 41. The connection terminal 46 has a plurality of terminal pins 46a and a retaining member 46b integrally holding the plurality of terminal pins 46a. The connection terminal 46 is disposed inside the connector portion 41b of the sensor housing 41, and one end of the terminal pins 46a is connected to the circuit board 44 disposed in the board mounting portion 41c. The other end of the terminal pins 46a of the connection terminal 46 can be electrically connected to a connector connected to the outside of the connector portion 41b.

[0106] In this embodiment, the terminal pin 46a is formed in the shape of the letter L, and the portion of the terminal pin 46a that connects to the circuit board 44 is connected to the circuit board 44 in the thickness direction of the circuit board 44. The portion of the terminal pin 46a that is electrically connected to an external connector is arranged radially. Thus, the connection terminal 46 can electrically connect the circuit board 44 to an external connector.

[0107] Next, the structure in which the magnetic collecting assembly 40 and the magnetic shield 70 are mounted relative to the first housing 21 will be described. Figure 8 This is a detailed view of the portion of the housing 21 where the magnetic collecting assembly 40 and the magnetic shield 70 are mounted. Figure 9 This indicates that the magnetic shielding cover 70 is installed on Figure 8 A detailed diagram showing the state prior to the first housing 21. Figure 10 This indicates that the magnetizing assembly 40 is installed on Figure 9 A detailed view of the state prior to the first housing 21 is shown. The magnetizing assembly 40 is housed in and mounted on the housing portion 25 of the first housing 21. The magnetic shield 70 is mounted on the housing portion 25 together with the magnetizing assembly 40 using mounting bolts 78, which serve as fastening members for mounting the magnetizing assembly 40 to the housing portion 25.

[0108] An opening 26 is formed in the portion of the housing 25 where the magnetic collecting assembly 40 is installed, opening outward in a radial direction (see reference). Figure 10The opening 26 of the receiving part 25 becomes an opening in the space inside the receiving part 25. In addition, on the outer surface of the receiving part 25 in the radial direction, a threaded hole 27 is formed on the side of the opening 26 for screwing in the mounting bolt 78 for mounting the magnetizing assembly 40 to the receiving part 25.

[0109] The magnetic collecting assembly 40 has a flange 41a that is mounted radially outward relative to the receiving portion 25, and the magnetic shield 70 has a shield mounting portion 73 that is mounted radially outward relative to the receiving portion 25. The magnetic shield 70 is mounted to the receiving portion 25 by screwing a mounting bolt 78 into a threaded hole 27 in the receiving portion 25 with the flange 41a of the magnetic collecting assembly 40 positioned between the shield mounting portion 73 and the receiving portion 25.

[0110] In detail, when the magnetizing assembly 40 is installed in the receiving part 25, the bushing 48 made of metal material is inserted into the two bushing insertion holes 41aa of the flange part 41a (see reference). Figure 6 ), and bushing 48 is positioned in bushing insertion hole 41aa.

[0111] On the other hand, the magnetic shielding cover 70, formed by bending a metal plate component, has a shielding mounting portion 73 formed radially in the thickness direction of the plate. Mounting holes 75 are formed on the shielding mounting portion 73 at two locations corresponding to the two threaded holes 27 formed in the receiving portion 25. Furthermore, the shielding mounting portion 73 has a through hole 74 through which the connector portion 41b of the magnetic collecting assembly 40 passes. The through hole 74 is located between the two mounting holes 75 formed in the shielding mounting portion 73 and is formed to penetrate the shielding mounting portion 73 in the thickness direction. Additionally, the first shielding portion 71 and the second shielding portion 72 of the magnetic shielding cover 70 are formed by radial bending from both sides of the shielding mounting portion 73 in the axial direction.

[0112] When the magnetizing assembly 40 and the magnetic shield 70 are installed in the receiving part 25, for the magnetizing assembly 40, the substrate mounting part 41c is inserted into the inside of the receiving part 25 from the opening 26 of the receiving part 25 with the connector part 41b located radially outward. At this time, the magnetizing assembly 40 is inserted into the step part 41d formed in the sensor housing 41 (see reference). Figure 5 Inserted in the state of ) . Thus, the magnetic collecting assembly 40 is configured with a magnetic collecting yoke 43, a circuit board 44 substrate mounting portion 41c housed in the housing portion 25, and an O-ring 47 configured to abut against both the outer peripheral surface of the sensor housing 41 and the inner peripheral surface of the housing portion 25.

[0113] The magnetic shield 70 is mounted by positioning the flange 41a of the magnetic collecting assembly 40, which is housed in the receiving portion 25, between the shield mounting portion 73 of the magnetic shield 70 and the radially outer surface of the receiving portion 25. In this state, the mounting bolt 78 passes through the mounting hole 75 of the shield mounting portion 73 and the hole inside the cylinder of the bushing 48, which is positioned in the bushing insertion hole 41aa of the flange 41a, and engages with the threaded hole 27 formed in the receiving portion 25. Thus, the magnetic shield 70 and the magnetic collecting assembly 40 are mounted together in the receiving portion 25 of the first housing 21 and fixed to the first housing 21.

[0114] At this time, the connector portion 41b of the magnetizing assembly 40 penetrates the through hole 74 of the shield mounting portion 73 from the inner side to the outer side in the radial direction. As a result, with the magnetic shield 70 covering and mounted on the receiving portion 25, the connector portion 41b of the magnetizing assembly 40 is exposed to the outer side of the magnetic shield 70, and can be connected to an external connector.

[0115] The magnetizing assembly 40, which is fixed to the first housing 21 with the substrate mounting portion 41c housed inside the housing portion 25, is fixed to the first housing 21 with the magnetizing yoke 43 of the magnetizing assembly 40 inserted between the flange portions 51 of each of the pair of stators 50. Thus, the magnetizing yoke 43 is fixed to the first housing 21 with the first magnetizing yoke 43a and the second magnetizing yoke 43b respectively inserted between the flange portions 51 of the pair of stators 50 and overlapping the flange portions 51 of the stators 50 with a gap in the axial direction.

[0116] With the magnetizing assembly 40 installed in the first housing 21, the connector portion 41b of the magnetizing assembly 40 is configured to be exposed to the outside of the housing portion 25, and also exposed from the magnetic shield 70. By connecting the connector portion 41b to the connector of the signal line that transmits the electrical signal from the torque sensor 10 to the ECU 100, the connection terminal 46 configured in the connector portion 41b is electrically connected to the signal line that transmits the electrical signal to the ECU 100.

[0117] Next, the function of the steering system 80 will be explained. When operating the steering wheel 81 while driving a vehicle equipped with the steering system 80, the steering force applied to the steering wheel 81 is transmitted from the steering wheel 81 to the steering shaft 82. The steering force transmitted to the steering shaft 82 is transmitted as a steering torque from the steering shaft 82 to the intermediate shaft 85, and from the intermediate shaft 85 to the first pinion 88a via the short shaft 87. As a result, the steering gear 88 with the first pinion 88a converts the rotational motion transmitted from the first pinion 88a into the linear motion of the rack 88b, causing the tie rod 89 to actuate.

[0118] Furthermore, the steering device 80 of this embodiment includes an electric motor 102 that generates an auxiliary steering torque to assist the driver in steering. The electric motor 102 generates the auxiliary steering torque based on the steering torque detected by the torque sensor 10 disposed between the short shaft 87 and the first pinion 88a.

[0119] The torque sensor 10 detects the steering torque applied to the short shaft 87 based on the angle of relative rotation between the short shaft 87 and the first pinion 88a. Specifically, the short shaft 87 and the first pinion 88a are connected via a torsion bar 87a, so when steering torque is applied to the short shaft 87, it is transmitted between the short shaft 87 and the first pinion 88a via the torsion bar 87a. At this time, the torsion bar 87a is slightly twisted, causing the short shaft 87 and the first pinion 88a to rotate relative to each other.

[0120] In the torque sensor 10, a magnet 55 is mounted on a short shaft 87, and a stator 50 is mounted on a first pinion 88a. Thus, when the short shaft 87 and the first pinion 88a rotate relative to each other, the magnet 55 and the stator 50 of the torque sensor 10 also rotate relative to each other. The angle of relative rotation between the magnet 55 and the stator 50 increases as the steering torque acting between the short shaft 87 and the first pinion 88a increases.

[0121] When the magnet 55 and the stator 50 rotate relative to each other, the magnetic flux acting on the stator 50 from the magnet 55 changes. The magnetic yoke 43, located near the stator 50, can detect this change in magnetic flux. Therefore, when the magnet 55 and the stator 50 rotate relative to each other as the short shaft 87 rotates relative to the first pinion 88a, the magnetic yoke 43 located near the stator 50 can detect this change in magnetic flux.

[0122] Thus, the magnetic flux acting on the stator 50 from the magnet 55, detected by the magnetic yoke 43, varies according to the angle of relative rotation between the magnet 55 and the stator 50. The Hall IC 45 uses a Hall element to detect the magnetic flux variation based on the angle of relative rotation between the magnet 55 and the stator 50 detected by the magnetic yoke 43, and converts it into an electrical signal using an output circuit, which is transmitted from the connection terminal 46 to the outside of the first housing 21 and then to the ECU 100. In other words, the torque sensor 10 detects the steering torque applied to the short shaft 87 by using the magnetic yoke 43 and the Hall IC 45 to detect the change in magnetic flux acting on the stator 50 from the magnet 55, and transmits the detected steering torque as an electrical signal to the ECU 100.

[0123] The ECU 100 operates the electric motor 102 based on the electrical signal transmitted from the torque sensor 10, causing the electric motor 102 to generate auxiliary steering torque. Specifically, the electrical signal transmitted from the Hall IC 45 of the torque sensor 10 to the ECU 100 varies according to the angle of relative rotation between the magnet 55 and the stator 50, and also varies based on the steering torque T acting between the short shaft 87 and the first pinion 88a. Therefore, the ECU 100 uses the electrical signal transmitted from the Hall IC 45 of the torque sensor 10 as information about the variation of the steering torque T acting on the short shaft 87 and the first pinion 88a, and adjusts the power value X supplied to the electric motor 102 based on the electrical signal transmitted from the Hall IC 45, causing the electric motor 102 to generate auxiliary steering torque.

[0124] That is, the ECU 100 obtains the steering torque T signal from the torque sensor 10, the vehicle speed signal V from the vehicle speed sensor 101, and the operation information Y of the electric motor 102 from the rotation detection device installed on the electric motor 102. Based on this operation information Y, the steering torque T, and the vehicle speed signal V, the electric motor 102 generates auxiliary steering torque. The auxiliary steering torque generated by the electric motor 102 is transmitted to the second pinion 88c. The steering gear 88 with the second pinion 88c converts the rotational motion transmitted from the second pinion 88c into linear motion of the rack 88b. Thus, the auxiliary steering torque generated by the electric motor 102 assists the driver in applying the steering force to the steering wheel 81.

[0125] Thus, the torque sensor 10 detects the steering torque applied to the short shaft 87 by utilizing the magnetic yoke 43 and Hall IC 45 to detect changes in the magnetic flux acting on the stator 50 from the magnet 55. Therefore, when magnetic noise acts on the torque sensor 10, the magnetic flux detected by the magnetic yoke 43 and Hall IC 45 differs from the magnetic flux detected by the relative rotation between the magnet 55 and the stator 50, sometimes making it impossible to detect the steering torque with high accuracy.

[0126] For example, if a magnetic object different from the torque sensor 10 is located near the torque sensor 10, the magnetic field from the magnetic object, i.e., the external magnetic field, acts on the Hall IC 45. The Hall IC 45 detects the magnetic flux of the external magnetic field. Therefore, the magnetic flux detected by the Hall IC 45 may sometimes be different from the magnetic flux acting on the stator 50 from the magnet 55. That is, the Hall IC 45 may misdetect the magnetic flux due to the external magnetic field, and the torque sensor 10 may misdetect the steering torque based on the magnetic flux detection.

[0127] In particular, the Hall IC 45 is disposed on a circuit board 44 facing axially in the thickness direction, and detects magnetic flux from the magnetic yoke 43 clamped between its two axial sides. Therefore, when an external magnetic field acts on the Hall IC 45 axially, the Hall IC 45 is prone to falsely detecting magnetic flux. That is, on the side of the first housing 21 relative to the receiving portion 25 in the axial direction of the external magnetic body ( Figure 5 The second housing 31, located on the side of the housing 25 relative to the upper side of the paper surface, and on the axial side relative to the housing 25 ( Figure 5 When the Hall IC 45 is located near the housing 25 (relative to the lower side of the paper), an external magnetic field generated by an external magnetic body acts on the Hall IC 45 axially. In this case, the external magnetic field acting on the Hall IC 45 is in the same direction as the direction in which the Hall IC 45 detects the magnetic flux from the magnetic yoke 43, so the Hall IC 45 is prone to falsely detecting the magnetic flux.

[0128] In contrast, the torque sensor 10 of this embodiment is equipped with a magnetic shield 70 covering the receiving portion 25 of the receiving magnetic collection assembly 40 in the first housing 21. Therefore, even when a magnetic body different from the torque sensor 10 approaches the receiving portion 25 from the axial direction of the side where the first housing 21 is located or the side where the second housing 31 is located, the magnetic field of the magnetic body can be shielded relative to the inside of the receiving portion 25, thus suppressing the magnetic field of the magnetic body from acting on the inside of the receiving portion 25.

[0129] Therefore, even when a magnetic object different from the torque sensor 10 approaches the housing 25, the following situation can be suppressed: the magnetic field of the magnetic object acts on the magnetic yoke 43 and Hall IC 45 of the magnetic collecting assembly 40 housed in the housing 25, causing the Hall IC 45 to falsely detect magnetic flux. Therefore, the torque sensor 10 can detect steering torque with high accuracy, and the steering device 80 can generate auxiliary steering torque based on the steering torque detected by the torque sensor 10.

[0130] As described above, in the torque sensor 10 of the steering device 80 of this embodiment, the first housing 21 has a receiving portion 25 protruding radially outward. The magnetic yoke 43 is configured to clamp the Hall IC 45 from both sides axially when the magnetic collecting assembly 40 is housed in the receiving portion 25, using the first magnetic yoke 43a and the second magnetic yoke 43b. Furthermore, a magnetic shield 70 is installed in the receiving portion 25. This magnetic shield 70 has a first shield 71 covering the receiving portion 25 axially from the side opposite to where the second housing 31 is located, and a second shield 72 covering the receiving portion 25 axially from the side where the second housing 31 is located. Therefore, even when a magnetic body is close to the receiving portion 25 where the magnetic yoke 43 and the Hall IC 45 are arranged internally, the magnetic shield 70 can shield the external magnetic field from the magnetic body acting on the Hall IC 45 in the detection direction of the magnetic flux detected by the Hall IC 45, i.e., axially. Therefore, when using the magnetic yoke 43 and Hall IC 45 to detect the change in magnetic flux acting on the stator 50 from the magnet 55, the influence of the external magnetic field can be suppressed, and the torque sensor 10 can appropriately detect the steering torque.

[0131] Furthermore, the magnetic yoke 43 and Hall IC 45, used to detect the magnetic flux acting on the stator 50 from the magnet 55, are housed in a receiving portion 25 that protrudes radially outward from the first housing 21. Therefore, the magnetic shield 70 does not need to be of a complex shape; by covering the receiving portion 25 from both sides axially, it can shield against external magnetic fields from the magnetic body outside the torque sensor 10 relative to the magnetic yoke 43 and Hall IC 45. Thus, the magnetic shield 70 can shield against external magnetic fields without being of a complex shape, thereby reducing the cost of manufacturing the magnetic shield 70.

[0132] In other words, when a cylindrical yoke is arranged outside a cylindrical permanent magnet as in Patent Document 1, and an annular magnetic collecting ring is arranged outside the yoke, the magnetic shielding member needs to be arranged around the entire circumference of the magnetic collecting ring to shield against the external magnetic field from the external magnetic body, as in Patent Document 1. In this case, the shape of the magnetic shielding member becomes complex, making its manufacture or installation difficult. In contrast, in this embodiment, the magnetic collecting yoke 43 and Hall IC 45 are housed in a receiving portion 25 that protrudes radially outward from the first housing 21. Therefore, by providing a shape that covers the receiving portion 25 from both sides in the axial direction, the magnetic shielding cover 70 can shield against the external magnetic field from the external magnetic body relative to the magnetic collecting yoke 43 and Hall IC 45. Thus, the magnetic shielding cover 70 can shield against the external magnetic field without having a complex shape, reducing the cost of manufacturing the magnetic shielding cover 70. As a result, the influence of the external magnetic field during torque detection can be suppressed while suppressing the increase in manufacturing costs.

[0133] Furthermore, at least one of the first shielding portion 71 and the second shielding portion 72 of the magnetic shielding cover 70 is arranged axially overlapping with the Hall IC 45. Therefore, the magnetic shielding cover 70 can shield the Hall IC 45 from the external magnetic field acting axially in the detection direction of the magnetic flux detected by the Hall IC 45 using the first shielding portion 71 and the second shielding portion 72 arranged overlapping with the Hall IC 45. Thus, when detecting changes in magnetic flux acting on the stator 50 from the magnet 55 using the Hall IC 45, the influence of the external magnetic field can be suppressed using the magnetic shielding cover 70. As a result, the influence of the external magnetic field when detecting torque can be suppressed.

[0134] Furthermore, the magnetic shielding cover 70 is mounted to the housing 25 together with the magnetic collecting assembly 40 using mounting bolts 78 that mount the magnetic collecting assembly 40 to the housing 25. Therefore, it is not necessary to replace the components used to mount the magnetic shielding cover 70 to the housing 25, thus reducing the number of parts. Additionally, since the magnetic shielding cover 70 is mounted to the housing 25 together with the magnetic collecting assembly 40 using mounting bolts 78, the number of steps involved in mounting the magnetic collecting assembly 40 and the magnetic shielding cover 70 to the housing 25 can be reduced. As a result, the increase in manufacturing costs can be suppressed.

[0135] Furthermore, the magnetic shielding cover 70 has a shielding mounting portion 73, and the magnetic collecting assembly 40 has a flange portion 41a. The magnetic shielding cover 70 positions the flange portion 41a of the magnetic collecting assembly 40 between the shielding mounting portion 73 and the receiving portion 25, and is mounted to the receiving portion 25 using mounting bolts 78. Therefore, the magnetic shielding cover 70 and the magnetic collecting assembly 40 can be properly mounted to the receiving portion 25 using shared mounting bolts 78. This reduces the number of components and the number of steps required to mount the magnetic collecting assembly 40 and the magnetic shielding cover 70 to the receiving portion 25. As a result, it helps to suppress increases in manufacturing costs.

[0136] Furthermore, in cases where a cylindrical yoke is arranged outside a cylindrical permanent magnet, as in Patent Document 1, and an annular magnetic collecting ring is arranged outside the yoke, the magnetic shielding component also needs to cover the magnetic collecting ring axially. Thus, in order to utilize the magnetic shielding component covering the magnetic collecting ring axially, as in Patent Document 1, the magnetic shielding component needs to be sandwiched and fixed between a housing containing a torque sensor and a housing axially connected to that housing. However, dimensional errors occur during component manufacturing. Therefore, when the magnetic shielding component is sandwiched between the housings, errors in the relative positional relationship between the component supported on one side of the housing and the component supported on the other side of the housing increase the amount of dimensional error in the thickness of the magnetic shielding component plate.

[0137] In this embodiment, the magnetic yoke 43 is fixed to the first housing 21, and the stator 50 and the first pinion 88a are supported together in the second housing 31. Therefore, when the magnetic shield 70 is clamped between the first housing 21 and the second housing 31, errors in the axial distance between the flange 51 of the stator 50 and the magnetic yoke 43 can easily increase the dimensional error in the thickness of the magnetic shield 70 plate. In this case, when detecting changes in magnetic flux from the magnet 55 acting on the stator 50 using the magnetic yoke 43, errors in the detected values ​​are easily generated due to the error in the distance between the flange 51 of the stator 50 and the magnetic yoke 43, thus easily causing errors in the detected value of the steering torque of the torque sensor 10.

[0138] In contrast, in this embodiment, the magnetic shield 70 is not sandwiched between the first housing 21 and the second housing 31, but is mounted radially outward on the receiving portion 25. Therefore, the magnetic shield 70 can suppress factors that increase the error in the relative positional relationship between the stator 50 and the magnetic yoke 43. This allows for high-precision configuration of the stator 50 and the magnetic yoke 43, improving the detection accuracy of the magnetic flux by the magnetic yoke 43. Consequently, the magnetic flux acting on the stator 50 from the magnet 55 can be detected with high precision using the magnetic yoke 43, enabling appropriate detection of steering torque.

[0139] Furthermore, the shielding mounting portion 73 has a through hole 74 through which the connector portion 41b of the magnetizing assembly 40 passes. The connector portion 41b passes through the through hole 74 from the radially inner side to the outer side. Therefore, the shielding mounting portion 73 can shield external magnetic fields while enabling the connection between the external connector and the connector portion 41b. Thus, while ensuring the electrical connection between the Hall IC 45 of the magnetizing assembly 40 and the ECU 100, thus ensuring the torque detection path, the magnetic shield 70 can shield external magnetic fields. As a result, steering torque can be properly detected, and the influence of external magnetic fields during torque detection can be suppressed.

[0140] Furthermore, the housing 20 includes a first housing 21 with a receiving portion 25 and a second housing 31 connected to the first housing 21. The first shielding portion 71 and the second shielding portion 72 of the magnetic shielding cover 70 cover the receiving portion 25 from opposite sides in the axial direction. This allows for the easy acquisition of a structure that shields the external magnetic field from external magnetic bodies relative to the magnetic yoke 43 and the Hall IC 45. As a result, the influence of the external magnetic field during torque detection can be suppressed while minimizing the increase in manufacturing costs.

[0141] Furthermore, the receiving portion 25 is disposed near the portion of the first housing 21 that connects to the second housing 31. The radial diameter of the end of the second housing 31 connected to the first housing 21 is greater than the radial diameter of the portion of the first housing 21 opposite to the side where the receiving portion 25 is located. As a result, the radial length of the surface of the receiving portion 25 facing the second housing 31 is shorter than the radial length of the surface facing the opposite side of the second housing 31.

[0142] On the other hand, in the magnetic shield 70 installed on the housing portion 25 thus formed, the radial length of the second shield portion 72 covering the side where the second housing 31 is located is shorter than the radial length of the first shield portion 71 covering the opposite side of the side where the second housing 31 is located. Therefore, the magnetic shield 70 can cover the housing portions 25, which protrude radially from the housing 20 with different axial protrusions on both sides, from both sides in the axial direction to the greatest extent possible. As a result, the magnetic shield 70 can shield the magnetic field acting on the inside of the housing portion 25 from a magnetic body that can approach the housing portion 25 protruding from the housing 20. As a result, the influence of the external magnetic field when detecting torque can be suppressed.

[0143] Furthermore, the receiving portion 25 has an opening 26 that opens radially outward. The magnetizing assembly 40 is received within the receiving portion 25 by being inserted through the opening 26 into the inside of the receiving portion 25, thus allowing the magnetizing assembly 40 to be easily positioned inside the receiving portion 25. Consequently, the magnetizing yoke 43 and Hall effect IC 45 of the magnetizing assembly 40 can be easily positioned inside the receiving portion 25, and the magnetizing yoke 43 can be easily positioned appropriately relative to the stator 50. As a result, steering torque can be appropriately detected, and the increase in manufacturing costs can be suppressed.

[0144] Furthermore, an O-ring 47 is disposed between the outer peripheral surface of the sensor housing 41 of the magnetic collecting assembly 40 and the inner peripheral surface of the receiving portion 25, thereby preventing water or the like from entering the receiving portion 25. As a result, malfunctions of the Hall IC 45 caused by water or the like entering the receiving portion 25 can be suppressed, ensuring durability.

[0145] Furthermore, the magnetizing assembly 40 has a cover 42 that covers the circuit board 44, and an O-ring 47 is positioned radially outward from the location where the cover 42 is positioned. Therefore, the circuit board 44 can be sealed without placing a sealing member between the sensor housing 41 and the cover 42. This reduces the number of sealing members required to prevent water or other contaminants from entering the circuit board 44. Consequently, the number of components can be reduced, and the number of assembly steps when attaching the magnetizing assembly 40 to the housing 20 can be decreased. As a result, durability can be ensured while minimizing increases in manufacturing costs.

[0146] [Variation Example]

[0147] Furthermore, in the above embodiment, the radial length of the first shielding portion 71 of the magnetic shielding cover 70 is longer than the radial length of the second shielding portion 72, but the first shielding portion 71 and the second shielding portion 72 can also be formed in other ways. The magnetic shielding cover 70 can cover the receiving portion 25 as much as possible from both sides in the detection direction of the magnetic flux detected by the Hall IC 45 disposed inside the receiving portion 25, and the relative shape relationship between the first shielding portion 71 and the second shielding portion 72 is not limited.

[0148] The preferred embodiments of this disclosure have been described above, but this disclosure is not limited to the contents described in the above embodiments. The structures described as embodiments and variations can also be appropriately combined.

[0149] Explanation of reference numerals in the attached figures

[0150] 10. Torque sensor; 20. Housing; 21. First housing; 23, 47. O-ring; 25. Receiving part; 26. Opening; 31. Second housing; 37, 78. Mounting bolt; 40. Magnetizing assembly; 41. Sensor housing; 41a. Flange; 41aa. Bushing insertion hole; 41b. Connector; 41c. Substrate mounting part; 41d. Stepped part; 42. Cover; 42a. First cover; 42b. Second cover; 43. Magnetizing yoke; 43a. First magnetizing yoke; 43b. Second magnetizing yoke; 44. Circuit board; 45. Hall IC; 46. Connecting terminal; 50. Stator; 51. Flange; 52. Gear; 54. Carrier; 55. Magnet; 70. Magnetic shield; 71. First shield; 72. Second shield; 73. Shielding mounting part; 74. Through hole; 75. Mounting hole; 80. Steering device; 81. Steering wheel; 82. Steering shaft; 84. Universal joint; 85. Intermediate shaft; 86. Universal joint; 87. Short shaft; 87a. Torsion bar; 88. Steering gear; 88a. First pinion; 88b. Rack; 88c. Second pinion; 89. Tie rod; 90. Rack housing; 100. ECU; 101. Vehicle speed sensor; 102. Electric motor; 103. Ignition switch; 104. Power supply unit.

Claims

1. A torque sensor, wherein, This torque sensor features: The stator is fixed to the shaft; A cylindrical magnet is arranged opposite to the stator; A housing, on which the shaft, the stator, and the magnet are disposed on their inner sides; and A magnetic flux collecting assembly includes a magnetic flux collecting yoke and a Hall element. The magnetic flux collecting yoke detects changes in magnetic flux corresponding to changes in the relative position between the stator and the magnet. The Hall element converts the changes in magnetic flux detected by the magnetic flux collecting yoke into an electrical signal and outputs it. The housing has a receiving portion that protrudes radially outward toward the shaft and accommodates the magnetizing assembly. The magnetic collecting yoke has a first magnetic collecting yoke and a second magnetic collecting yoke. With the magnetic collecting assembly housed in the receiving portion, the first magnetic collecting yoke and the second magnetic collecting yoke clamp the Hall element from both sides of the shaft along its axial direction. A magnetic shield is installed in the receiving part, the magnetic shield having a first shield covering the receiving part from one side of the axial direction and a second shield covering the receiving part from the other side of the axial direction.

2. The torque sensor according to claim 1, wherein, At least one of the first shielding portion and the second shielding portion is configured to overlap with the Hall element in the axial direction.

3. The torque sensor according to claim 1 or 2, wherein, The magnetic shield is installed in the housing together with the magnetic collecting component using a fastening member that mounts the magnetic collecting component to the housing.

4. The torque sensor according to claim 3, wherein, The magnetic shielding cover has a shielding mounting portion that is mounted on the outer side of the receiving portion in the radial direction. The magnet collecting assembly has a flange portion that is mounted to the receiving portion from the outer side in the radial direction. The magnetic shielding cover positions the flange portion of the magnetic collecting assembly between the shielding mounting portion and the receiving portion, and is mounted to the receiving portion using the fastening member.

5. The torque sensor according to claim 4, wherein, The magnetizing assembly has a connector portion that connects to an external connector. The shielding mounting portion has a through hole through which the connector portion passes. The connector portion extends through the through hole from the inner side to the outer side in the radial direction.

6. The torque sensor according to any one of claims 1 to 5, wherein, The housing has a first housing and a second housing that are interconnected. The first housing has the receiving portion. The first shielding portion covers the receiving portion from the side opposite to the side where the second housing is located in the axial direction. The second shielding portion covers the receiving portion from the side where the second housing is located in the axial direction.

7. The torque sensor according to claim 6, wherein, The receiving portion is located near the portion of the first housing that connects to the second housing. The radial diameter of the end of the second housing that connects to the first housing is greater than the radial diameter of the portion of the first housing opposite to the side where the receiving portion is located relative to the second housing. For the magnetic shield, the radial length of the second shield is shorter than the radial length of the first shield.

8. The torque sensor according to any one of claims 1 to 7, wherein, An opening is formed in the receiving portion that faces outward in the radial direction. The magnetizing assembly is housed within the receiving portion by being inserted into the inside of the receiving portion through the opening.

9. The torque sensor according to claim 8, wherein, The magnetic collecting assembly includes a sensor housing, a circuit board with the Hall element configured thereon, and the magnetic collecting yoke mounted on the sensor housing. An O-ring is disposed between the outer peripheral surface of the sensor housing and the inner peripheral surface of the receiving part to abut against both.

10. The torque sensor according to claim 9, wherein, The magnetic collecting assembly has a cover that covers the circuit board mounted on the sensor housing. The O-ring is positioned radially outward from the position where the cover is positioned.

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