Torque sensor and method for manufacturing the same

Abstract

To hold down an increase in manufacturing costs and improve positioning precision.SOLUTION: In a torque sensor 1 having a column housing 10 in which a stator 30 is disposed inside and a magnetism collecting yoke assembly 40 having a magnetism collecting yoke 41 for detecting a change in magnetic flux of a stator 30, the magnetism collecting yoke assembly 40 has a body 50 for holding the magnetism collecting yoke 41 and a flange 51 projecting from the body 50, a screw component insertion hole 52 through which a screw component 70 passes and a positioning projection 55 projecting from the flange 51 around the screw component insertion hole 52 are formed in the flange 51, a column housing 10 has a sensor installation part 20 to which the magnetism collecting yoke assembly 40 is mounted, the positioning projection 55 is inserted into the sensor installation part 20, and a positioning recess 25 with which at least one portion of the positioning projection 55 comes into contact and multiple screw holes 27 that are formed in a bottom part 26 of the positioning recess 25 and with which a screw component 70 is threadedly engaged are formed.SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] The present disclosure relates to a torque sensor and a method for manufacturing a torque sensor. [Background technology]

[0002] There are various methods for detecting torque applied to a rotating body using torque sensors, and one example is a torque sensor that detects torque by detecting changes in magnetism. For example, the torque detection device described in Patent Document 1 has multiple permanent magnets, two magnetic rings arranged around the permanent magnets, two magnetic flux collectors that collect magnetic flux passing through a magnetic circuit forming member made of these permanent magnets and magnetic rings, and a magnetic sensing element that detects the magnetism of the magnetic flux collected by the magnetic flux collectors. As a result, when a torque acts on a rotating body that is the target of torque detection and a circumferential positional deviation occurs between the permanent magnets and the magnetic rings, the magnetic sensing element detects the change in magnetic flux that occurs between the two magnetic flux collectors due to the positional deviation, and detects the torque applied to the rotating body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-212198 A Summary of the Invention [Problem to be solved by the invention]

[0004] There are various types of torque sensor structures depending on ease of manufacture and maintenance, for example, a type in which a part in which a stator such as a magnetic ring or a magnetic flux collector ring is disposed and a part in which a magnetic flux collector yoke such as a magnetic sensing element is disposed are connected using screw fasteners. When the part in which the stator is disposed and the part in which the magnetic flux collector yoke is disposed are assembled separately and these parts are connected using screw fasteners, there is an advantage in terms of ease of manufacture and maintenance compared to when these are all integrally formed.

[0005] Here, when multiple parts are connected by screw fasteners, it is considered that the relative positional relationship between the two parts when assembled may vary due to the gap between the screw fasteners and the holes through which the screw fasteners pass. On the other hand, when detecting changes in magnetic flux with high accuracy using a magnetic flux collecting yoke, the relative positional relationship between the stator and the magnetic flux collecting yoke is important. Therefore, when a part in which a stator is disposed and a part in which a magnetic flux collecting yoke is disposed are connected by screw fasteners, it becomes difficult to ensure the relative positional relationship between the stator and the magnetic flux collecting yoke with high accuracy, and there is a risk that it becomes difficult to detect changes in magnetic flux with high accuracy using the magnetic flux collecting yoke.

[0006] However, if the components on which the stator and magnetic flux collector yoke are mounted are subjected to high-precision machining over a wide area in order to improve the positioning accuracy between the stator and magnetic flux collector yoke, this leads to increased manufacturing costs. For these reasons, it has been very difficult to improve the positioning accuracy between the stator and magnetic flux collector yoke without increasing manufacturing costs.

[0007] The present disclosure has been made in consideration of the above, and aims to provide a torque sensor and a method for manufacturing a torque sensor that can improve positioning accuracy while suppressing an increase in manufacturing costs. [Means for solving the problem]

[0008] The torque sensor of the present disclosure is a torque sensor including a housing in which a stator is disposed, a cylindrical magnet disposed facing the stator, and a magnetism collecting yoke assembly including a magnetism collecting yoke for detecting a change in magnetic flux corresponding to a change in the relative position between the stator and the cylindrical magnet, the magnetism collecting yoke assembly having a body that holds the magnetism collecting yoke while exposing it, and a flange that protrudes from the body, the flange having a plurality of screw fastener insertion holes through which screw fasteners used to attach the magnetism collecting yoke assembly to the housing pass, and a screw fastener insertion hole that is located around the screw fastener insertion hole and is formed on the flange. The housing has a sensor installation section to which the magnetic collecting yoke assembly is attached, and the sensor installation section has a housing insertion hole through which the magnetic collecting yoke exposed from the body is inserted from the outside of the housing to the inside of the housing, a plurality of positioning recesses formed recessed from the sensor installation section into which the positioning protrusions are inserted and into which at least a portion of the positioning protrusions come into contact, and a plurality of screw holes formed at the bottom of the positioning recesses into which the screw fasteners that have passed through the screw fastener insertion holes formed in the flange are screwed.

[0009] According to this configuration, the positioning recess is configured so that the positioning protrusion is inserted and at least a portion of the positioning protrusion comes into contact when the positioning protrusion is inserted, and the screw hole is configured so that the screw fastener passing through the screw fastener insertion hole is screwed into the screw hole. As a result, in a torque sensor in which the magnetic flux collecting yoke assembly is attached to the column housing by a screw fastener, the positioning accuracy can be improved only by the positioning protrusion 55 and the positioning recess, without performing high-precision machining over a wide area to improve the positioning accuracy between the stator and magnetic flux collecting yoke. As a result, the positioning accuracy can be improved while suppressing an increase in manufacturing costs.

[0010] In a preferred embodiment, the positioning protrusion is lightly press-fitted into the positioning recess.

[0011] According to this configuration, since the positioning protrusion is lightly press-fitted into the positioning recess, it is possible to further improve the positioning accuracy when attaching the magnetic flux collecting yoke assembly to the column housing. This makes it possible to improve the positioning accuracy while suppressing an increase in manufacturing costs.

[0012] In a preferred embodiment, the positioning protrusion has a protrusion extending in a direction in which the positioning protrusion is inserted into the positioning recess and protruding from an outer circumferential surface of the positioning protrusion.

[0013] According to this configuration, the positioning convex portion is formed with a protrusion extending in the insertion direction of the positioning convex portion into the positioning recess and protruding from the outer peripheral surface of the positioning convex portion, so that when the positioning convex portion is inserted into the positioning recess, the protrusion can be inserted while contacting the inner peripheral surface of the positioning recess. This makes it possible to further increase the positioning accuracy using the positioning convex portion and the positioning recess, thereby improving the positioning accuracy while suppressing an increase in manufacturing costs.

[0014] In a preferred embodiment, the projection has an arcuate shape when viewed in the extending direction of the projection.

[0015] According to this configuration, the protrusion is formed in an arc shape when viewed in the extending direction of the protrusion, so that the positioning accuracy using the positioning convex portion and the positioning concave portion is improved by the protrusion, and the positioning convex portion can be smoothly inserted into the positioning concave portion. This makes it possible to easily attach the magnetic flux collecting yoke assembly to the column housing, and improves the positioning accuracy while suppressing an increase in manufacturing costs.

[0016] In a preferred embodiment, the projection has a rectangular shape when viewed in the extending direction of the projection.

[0017] With this configuration, the protrusion can be formed in a shape that allows the positioning convexity to be inserted into the positioning recess with a light press fit, depending on the relative sizes of the outer diameter of the positioning convexity and the inner diameter of the positioning recess, and the materials of the positioning convexity and the column housing, etc.

[0018] In a preferred embodiment, the protrusion is formed in a shape having an edge portion when viewed in the extending direction of the protrusion.

[0019] With this configuration, the protrusion can be formed in a shape that allows the positioning convexity to be inserted into the positioning recess with a light press fit, depending on the relative sizes of the outer diameter of the positioning convexity and the inner diameter of the positioning recess, and the materials of the positioning convexity and the column housing, etc.

[0020] In a preferred embodiment, the projections are arranged in different numbers on the positioning protrusions.

[0021] According to this configuration, by making the number of protrusions different between the positioning protrusions, the positioning protrusion with more protrusions can be inserted into the positioning recess with high positioning accuracy, while the positioning protrusion with fewer protrusions can be inserted into the positioning recess with a certain degree of tolerance for relative misalignment when inserted into the positioning recess. As a result, even if slight dimensional errors occur when forming the positioning protrusions and positioning recesses, the dimensional errors can be absorbed and the magnetic flux collecting yoke assembly can be attached while ensuring positioning accuracy when attached to the column housing.

[0022] In a preferred embodiment, a metal bush formed in a substantially cylindrical shape is disposed in the flange, and the threaded fastener insertion hole is defined by an inner peripheral surface of the metal bush.

[0023] According to this configuration, a metal bush is disposed in the flange, and the screw fastener insertion hole is formed by the inner peripheral surface of the metal bush, so that the positioning accuracy can be improved by the positioning protrusion and the positioning recess, while the strength can be ensured when the magnetic flux collecting yoke assembly is attached to the column housing by the screw fastener. This makes it possible to improve positioning accuracy while suppressing increases in manufacturing costs.

[0024] In a preferred embodiment, the metal bush has an outer circumferential surface formed with a concave-convex portion having repeated concaves and convexes.

[0025] According to this configuration, the outer circumferential surface of the metal bushing has a concave-convex portion with repeated concaves and convexes, which increases the degree of adhesion between the flange and the metal bushing and prevents the metal bushing from coming off the flange, thereby improving positioning accuracy while preventing an increase in manufacturing costs.

[0026] In a preferred embodiment, the metal bush has a slit inclined with respect to the axial direction.

[0027] According to this configuration, by forming a slit inclined with respect to the axial direction in the metal bush, the edge of the slit catches on the flange, and a force is generated in the slit that resists the movement of the metal bush in the axial direction from the flange. This makes it possible to prevent the metal bush from coming off the flange, and improves positioning accuracy while preventing an increase in manufacturing costs.

[0028] The manufacturing method of a torque sensor according to the present disclosure is a manufacturing method of a torque sensor including a housing in which a stator is arranged, a cylindrical magnet arranged facing the stator, and a magnetism collecting yoke assembly including a magnetism collecting yoke for detecting a change in magnetic flux corresponding to a change in the relative position between the stator and the cylindrical magnet, the magnetism collecting yoke assembly having a body that holds the magnetism collecting yoke while exposing it, and a flange that protrudes from the body, the flange having a plurality of screw fastener insertion holes through which screw fasteners used to attach the magnetism collecting yoke assembly to the housing pass, and a screw fastener insertion hole that is located around the screw fastener insertion hole and on a side of the flange that is attached to the housing. In a torque sensor having a housing and a plurality of positioning protrusions protruding from a surface thereof, the housing has a sensor installation section to which the magnetic collecting yoke assembly is attached, and the sensor installation section has a housing insertion hole through which the magnetic collecting yoke exposed from the body is inserted from the outside of the housing to the inside of the housing, a plurality of positioning recesses formed recessed from the sensor installation section into which the positioning protrusions are inserted and with which at least a portion of the positioning protrusions come into contact, and a plurality of screw holes formed at the bottom of the positioning recesses and into which the screw fasteners that have passed through the screw fastener insertion holes formed in the flange are screwed, the positioning recesses are machined simultaneously with the machining of pilot holes for the screw holes.

[0029] According to this configuration, since the pilot holes for the screw holes are machined at the same time as the positioning recesses are machined in the sensor installation portion of the column housing, the number of work steps required for forming the positioning recesses and the screw holes can be reduced, thereby improving positioning accuracy while suppressing increases in manufacturing costs. Effect of the Invention

[0030] The torque sensor and the method for manufacturing the torque sensor according to the present disclosure have the advantage of being able to improve positioning accuracy while suppressing an increase in manufacturing costs. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is a schematic diagram of a steering device according to an embodiment. [Diagram 2] FIG. 2 is a perspective view of the steering device according to the embodiment. [Diagram 3] FIG. 3 is a perspective view of the torque sensor shown in FIG. [Figure 4] FIG. 4 is a side view of the torque sensor shown in FIG. [Diagram 5] FIG. 5 is a cross-sectional view taken along line AA of FIG. [Figure 6] FIG. 6 is a schematic diagram illustrating an overview of the magnet, the stator, and the magnetic flux collecting yoke that are arranged in the column housing. [Figure 7] FIG. 7 is a cross-sectional view of the main part at the position of part B in FIG. [Figure 8] FIG. 8 is a plan view of the magnetic flux collecting yoke assembly shown in FIG. [Figure 9] FIG. 9 is a cross-sectional view of a main part showing the internal structure of a body in the magnetic flux collecting yoke assembly shown in FIG. [Figure 10] FIG. 10 is a view taken along the line CC in FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line DD of FIG. [Figure 12] FIG. 12 is a detailed view of a sensor installation portion formed in the column housing shown in FIG. [Figure 13] FIG. 13 is a cross-sectional view taken at a position passing through two screw holes in the sensor installation portion shown in FIG. [Figure 14] FIG. 14 is an explanatory diagram showing a state in which the magnetic flux collecting yoke assembly is attached to the column housing. [Figure 15] FIG. 15 is a cross-sectional view taken along line E-E of FIG. [Figure 16] FIG. 16 is an explanatory diagram showing a modified example of the torque sensor according to the embodiment, in which a slit is formed in a metal bush. [Figure 17] FIG. 17 is an explanatory diagram showing a modified example of the torque sensor according to the embodiment, in which the protrusion is formed in a rectangular shape. [Figure 18]FIG. 18 is an explanatory diagram showing a modified example of the torque sensor according to the embodiment, in which the protrusion has an edge portion. [Figure 19] FIG. 19 is an explanatory diagram showing a modified example of the torque sensor according to the embodiment, in which the number of protrusions differs between the positioning convex portions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the following modes for carrying out the invention (hereinafter, referred to as embodiments). Furthermore, the components in the following embodiments include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the following embodiments can be appropriately combined.

[0033] [Embodiment] Fig. 1 is a schematic diagram of a steering device 80 according to an embodiment. Fig. 2 is a perspective view of the steering device 80 according to the embodiment. As shown in Fig. 1, the steering device 80 includes, in the order of transmission of force applied by an operator, a steering wheel 81, a steering shaft 82, a steering force assist mechanism 83, a universal joint 84, an intermediate shaft 85, and a universal joint 86, which are joined to a pinion shaft 87. As shown in Fig. 2, the steering force assist mechanism 83 is provided near the steering wheel 81, and is disposed in the vehicle interior separated from the outside.

[0034] The steering shaft 82 includes an input shaft 82a, an output shaft 82b, and a torsion bar (not shown). One end of the input shaft 82a is connected to the steering wheel 81, and the other end is connected to the torsion bar. The torsion bar is fitted into a hole provided in the center of the input shaft 82a, and is fixed to the input shaft 82a via a pin. One end of the output shaft 82b is connected to the torsion bar, and the other end is connected to a universal joint 84. The torsion bar is fixed to the output shaft 82b by being press-fitted into a hole provided in the center of the output shaft 82b. Rotational torque is transmitted between the input shaft 82a and the output shaft 82b via the torsion bar connected to both of them.

[0035] As shown in Fig. 1, the intermediate shaft 85 connects the universal joint 84 and the universal joint 86. One end of the intermediate shaft 85 is connected to the universal joint 84, and the other end is connected to the universal joint 86. One end of the pinion shaft 87 is connected to the universal joint 86, and the other end of the pinion shaft 87 is connected to the steering gear 88. The universal joint 84 and the universal joint 86 are, for example, Cardan joints. The rotation of the steering shaft 82 is transmitted to the pinion shaft 87 via the intermediate shaft 85. That is, the intermediate shaft 85 rotates together with the steering shaft 82.

[0036] As shown in Fig. 1, the steering gear 88 includes a pinion 88a and a rack 88b. The pinion 88a is connected to a pinion shaft 87. The rack 88b meshes with the pinion 88a. The steering gear 88 converts the rotational motion transmitted to the pinion 88a into linear motion by the rack 88b. The rack 88b is connected to a tie rod 89. The angle of the wheels changes as the rack 88b moves.

[0037] As shown in FIG. 1, the steering force assist mechanism 83 includes a reduction gear 92 and an electric motor 93. The reduction gear 92 is, for example, a worm reduction gear. The reduction gear 92 increases the torque generated by the electric motor 93 and transmits it to the output shaft 82b. As a result, the reduction gear 92 applies an assist steering torque to the output shaft 82b. The steering device 80 is a column assist type electric power steering device. Note that the column assist type electric power steering device refers to a power steering device in which an assist torque generated by the electric motor 93 is applied to a steering shaft 82 connected to a steering wheel 81.

[0038] As shown in Fig. 1, the steering device 80 includes an ECU (Electronic Control Unit) 90, a torque sensor 1, and a vehicle speed sensor 95. The electric motor 93, the torque sensor 1, and the vehicle speed sensor 95 are electrically connected to the ECU 90. The torque sensor 1 outputs the steering torque transmitted to the input shaft 82a to the ECU 90 through CAN (Controller Area Network) communication. The vehicle speed sensor 95 detects the traveling speed (vehicle speed) of a vehicle body on which the steering device 80 is mounted. The vehicle speed sensor 95 is provided on the vehicle body, and outputs the vehicle speed to the ECU 90 through CAN communication.

[0039] The ECU 90 controls the operation of the electric motor 93. The ECU 90 acquires signals from each of the torque sensor 1 and the vehicle speed sensor 95. When an ignition switch 98 is on, the ECU 90 is supplied with power from a power supply device 99 (e.g., an on-board battery). The ECU 90 calculates an auxiliary steering command value based on the steering torque and the vehicle speed. The ECU 90 adjusts the value of power supplied to the electric motor 93 based on the auxiliary steering command value. The ECU 90 acquires information on the induced voltage of the electric motor 93 or information output from a resolver or the like provided in the electric motor 93. The force required to operate the steering wheel 81 is reduced by the ECU 90 controlling the electric motor 93.

[0040] FIG. 3 is a perspective view of the torque sensor 1 shown in FIG. 1. FIG. 4 is a side view of the torque sensor 1 shown in FIG. 3. FIG. 5 is a cross-sectional view taken along line AA in FIG. 4. The torque sensor 1 has a column housing 10, which is a housing in the torque sensor 1, and a magnetic flux collecting yoke assembly 40. The column housing 10 has a housing part 11, which is formed in a substantially cylindrical shape and is a part that becomes a housing in the column housing 10, and a flange part 15, which is a part that is formed in a flange shape around the housing part 11. In addition, in the column housing 10, a sensor installation part 20 is formed on a side surface of the housing part 11, and the magnetic flux collecting yoke assembly 40 is attached to the column housing 10 by being attached to the sensor installation part 20 with a screw part 70.

[0041] The housing part 11 of the column housing 10 has a space formed inside, and both ends in the axial direction of the cylinder that is the shape of the housing part 11 are openings 12 that communicate with the outside and inside of the housing part 11. In the torque sensor 1, an input shaft 82a of a steering shaft 82 enters the housing part 11 from one opening 12 of the housing part 11 of the column housing 10, and an output shaft 82b of the steering shaft 82 enters the housing part 11 from the other opening 12 of the housing part 11. At least a portion of a torsion bar connected to the input shaft 82a and the output shaft 82b is located inside the housing part 11 of the column housing 10.

[0042] Furthermore, within the case portion 11 of the column housing 10, a magnet 35 and a stator 30 are arranged for use in detecting torque based on changes in magnetism.

[0043] 6 is a schematic diagram for explaining an overview of the magnet 35, the stator 30, and the magnetic flux collecting yoke 41 arranged in the column housing 10. One of the magnet 35 and the stator 30 arranged in the case part 11 of the column housing 10 is attached to the input shaft 82a, and the other is attached to the output shaft 82b. In this embodiment, the magnet 35 is attached to the input shaft 82a in the case part 11 of the column housing 10, and the stator 30 is attached to the output shaft 82b in the case part 11 of the column housing 10. Of these, the magnet 35 is formed in a substantially cylindrical shape, and is a multi-pole magnet in which a plurality of N poles and S poles are alternately arranged in the circumferential direction.

[0044] The stator 30 has a ring portion 31 and teeth portions 32. The ring portion 31 is formed in an annular plate shape with its thickness direction being in the axial direction. The teeth portions 32 extend from the inner periphery of the annular ring portion 31 toward the axial direction of the ring portion 31, and are formed in a plate shape with the thickness direction of the plate being oriented in the radial direction of the ring portion 31. The teeth portions 32 are arranged in a line in the circumferential direction of the ring portion 31 with a plurality of teeth portions 32 spaced apart from one another.

[0045] The stator 30 thus formed has a ring portion 31 and teeth portion 32, and has a first stator 30a and a second stator 30b formed in the same shape. That is, the first stator 30a has a circular first ring portion 31a and a plurality of first teeth portions 32a, and the second stator 30b has a circular second ring portion 31b and a plurality of second teeth portions 32b. The first stator 30a and the second stator 30b are both attached to the same shaft such that both ring portions 31 are located on the same axis and are oriented in a direction away from the other stator 30, and in this embodiment, both are attached to the output shaft 82b.

[0046] That is, the first stator 30a is arranged with the first teeth 32a extending from the first ring portion 31a toward the second stator 30b, and the second stator 30b is arranged with the second teeth 32b extending from the second ring portion 31b toward the first stator 30a. At this time, since the first teeth 32a and the second teeth 32b are each provided in the first ring portion 31a and the second ring portion 31b with a plurality of teeth spaced apart, the first stator 30a and the second stator 30b are combined such that the teeth 32 of the stator 30 are located in a portion in the circumferential direction where the teeth 32 of the other stator 30 are not located.

[0047] The magnet 35 attached to the input shaft 82a is disposed inside the first stator 30a and the second stator 30b thus combined. The magnet 35 and the stator 30 are disposed in the housing 11 with the axial direction thereof coinciding with the axial direction of the housing 11 of the column housing 10. For this reason, the magnet 35 and the stator 30 are disposed in the column housing 10 with the outer peripheral surface of the magnet 35 facing the teeth 32 of the stator 30. By disposing the magnet 35 and the stator 30 in this positional relationship, when torque is transmitted between the input shaft 82a and the output shaft 82b via a torsion bar and the input shaft 82a and the output shaft 82b rotate slightly relative to each other, the relative positional relationship between the magnet 35 and the stator 30 changes, and accordingly the magnetic flux acting on the stator 30 from the magnet 35 changes.

[0048] Further, a magnetic flux collecting yoke 41 of the magnetic flux collecting yoke assembly 40 is disposed near the stator 30. The magnetic flux collecting yoke 41 is a member for detecting a change in the magnetic flux acting on the stator 30 from the magnet 35, and is disposed near the ring portion 31 of the stator 30. Since the stator 30 includes a first stator 30a and a second stator 30b, the magnetic flux collecting yoke 41 includes a first magnetic flux collecting yoke 41a and a second magnetic flux collecting yoke 41b corresponding to the first stator 30a and the second magnetic flux collecting yoke 41b. That is, the magnetic flux collecting yoke 41 includes a first magnetic flux collecting yoke 41a disposed near the first ring portion 31a of the first stator 30a, and a second magnetic flux collecting yoke 41b disposed near the second ring portion 31b of the second stator 30b.

[0049] The magnetic flux collecting yoke 41 is located between two ring portions 31 of the stator 30. That is, the first magnetic flux collecting yoke 41a is located near the surface side of the first ring portion 31a of the first magnetic flux collecting yoke 41a where the second ring portion 31b is located, and the second magnetic flux collecting yoke 41b is located near the surface side of the second ring portion 31b of the second magnetic flux collecting yoke 41b where the first ring portion 31a is located. In this way, the magnetic flux collecting yoke 41 is located near the ring portion 31, so that the magnetic flux collecting yoke 41 can detect a change in the magnetic flux acting on the stator 30 from the magnet 35 when the input shaft 82a and the output shaft 82b rotate slightly relative to each other.

[0050] Furthermore, a Hall IC 42 is disposed between the two magnetism collecting yokes 41. The Hall IC 42 is disposed between the magnetism collecting yokes 41 at a position away from a portion of the magnetism collecting yoke 41 located near the ring portion 31 of the stator 30. The Hall IC 42 is capable of detecting a change in the magnetic flux density acting on the two magnetism collecting yokes 41, converting the detected change in the magnetic flux density into an electric signal, and outputting the electric signal. Note that a magnetic sensor that applies the magnetoresistance effect or the tunnel magnetoresistance effect can be used instead of the Hall IC. In short, it is sufficient if the change in the magnetic flux density occurring between the magnetism collecting yokes 41 can be output as an electric signal.

[0051] Fig. 7 is a cross-sectional view of a main part at the position of part B in Fig. 4. The stator 30 disposed in the case part 11 of the column housing 10 is held by a carrier 38 in the case part 11. The carrier 38 is formed in a substantially cylindrical shape with an inner diameter slightly larger than the inner diameter of the stator 30 or the outer diameter at the position of the teeth part 32 (see Fig. 6) of the stator 30, and an outer diameter smaller than the outer diameter of the ring part 31 of the stator 30.

[0052] Moreover, the length of the carrier 38 is approximately equal to the height of the teeth portion 32 of the stator 30. In other words, the length of the carrier 38 is approximately equal to the distance between the first ring portion 31a and the second ring portion 31b when the first stator 30a and the second stator 30b are combined together.

[0053] The first stator 30a and the second stator 30b are oriented so that their axial directions are in the same direction as the axial direction of the carrier 38, and the first teeth 32a and the second teeth 32b are inserted into the inside of the carrier 38 from different end sides in the longitudinal direction of the carrier 38. As a result, the first stator 30a and the second stator 30b are held by the carrier 38 with the first teeth 32a and the second teeth 32b inserted into the inside of the carrier 38.

[0054] The first stator 30a and the second stator 30b are held by the carrier 38 in a state in which the first ring portion 31a and the second ring portion 31b are positioned outside the carrier 38 from different ends of the carrier 38 in the longitudinal direction.

[0055] The magnetism collecting yoke assembly 40 is attached to the column housing 10 in an orientation in which the magnetism collecting yoke 41 is disposed inside the housing portion 11 of the column housing 10. That is, the magnetism collecting yoke assembly 40 includes two magnetism collecting yokes 41, a first magnetism collecting yoke 41a and a second magnetism collecting yoke 41b, and when the magnetism collecting yoke 41 is positioned inside the housing portion 11 by attaching the magnetism collecting yoke assembly 40 to the column housing 10, the two magnetism collecting yokes 41 are disposed between the ring portions 31 located on both sides in the longitudinal direction of the carrier 38.

[0056] The two ring parts 31 and the two magnetic flux collecting yokes 41 arranged in this manner are grouped together, with the first ring part 31a and the first magnetic flux collecting yoke 41a arranged in close proximity, and the second ring part 31b and the second magnetic flux collecting yoke 41b arranged in close proximity. That is, the ring parts 31 and the magnetic flux collecting yokes 41 are arranged in pairs, forming two pairs. The paired ring parts 31 and the magnetic flux collecting yokes 41 have a relatively small clearance g in the axial direction of the housing 11, and the clearance g between the ring parts 31 and the magnetic flux collecting yokes 41 is approximately the same for the two pairs of ring parts 31 and the magnetic flux collecting yokes 41.

[0057] Fig. 8 is a plan view of the magnetic flux collecting yoke assembly 40 shown in Fig. 3. The magnetic flux collecting yoke assembly 40 has a body 50, a flange 51 formed to protrude from the body 50, and a magnetic flux collecting yoke 41 attached to the body 50. The body 50 is formed in a box shape, has a space inside, and holds the magnetic flux collecting yoke 41 while exposing it. In addition, the end of the body 50 that is located closer to the column housing 10 when the magnetic flux collecting yoke assembly 40 is attached to the column housing 10 is curved in the same direction as the cylindrical curvature that is the shape of the case part 11 of the column housing 10.

[0058] In detail, when the thickness direction of the body 50 is defined as the direction in the axial direction of the cylinder that is the shape of the casing 11 when the magnetic flux collecting yoke assembly 40 is attached to the column housing 10, the size of the body 50 in the thickness direction is small. Also, when the direction in which the magnetic flux collecting yoke assembly 40 is attached to the column housing 10 is defined as the length direction of the body 50, and the directions perpendicular to the thickness direction and length direction are defined as the width direction of the body 50, the sizes of the body 50 in the length direction and width direction are larger than the size in the thickness direction, and are formed to a predetermined size.

[0059] The magnetic flux collecting yoke 41 is disposed at an end of the body 50 that is located closer to the column housing 10 when the magnetic flux collecting yoke assembly 40 is attached to the column housing 10, i.e., at a curved portion of the body 50. The magnetic flux collecting yoke 41 is formed in a plate shape such that the thickness direction of the body 50 is also the thickness direction of the magnetic flux collecting yoke 41. The magnetic flux collecting yoke 41 is disposed in two pieces spaced apart from each other in the thickness direction of the body 50 (see FIG. 7). The two magnetic flux collecting yokes 41 are both formed in a shape that, when viewed in the thickness direction, is curved to be approximately concentric with the curved portion of the body 50.

[0060] The flanges 51 formed to protrude from the body 50 are disposed on both sides in the width direction of the body 50, and are each formed to protrude from the body 50. The flanges 51 disposed on both sides of the body 50 are formed in a plate shape such that the thickness direction of the flanges 51 is the length direction of the body 50.

[0061] In addition, a connection terminal 43, which is the part of the torque sensor 1 that is electrically connected to the ECU 90, is arranged on the side of the magnetic flux collecting yoke assembly 40 opposite to the side on which the magnetic flux collecting yoke 41 is arranged in the longitudinal direction of the body 50.

[0062] Fig. 9 is a cross-sectional view of a main part showing the internal structure of the body 50 in the magnetism collecting yoke assembly 40 shown in Fig. 8. The Hall IC 42 is disposed inside the body 50 of the magnetism collecting yoke assembly 40. The Hall IC 42 is disposed between the two magnetism collecting yokes 41 inside the body 50 while being spaced apart from the two magnetism collecting yokes 41. The two magnetism collecting yokes 41 held by the body 50 are disposed adjacent to the Hall IC 42 within the body 50 and exposed from within the body 50 in the length direction of the body 50. The Hall IC 42 is connected to a connection terminal 43 inside the body 50.

[0063] The Hall IC 42 detects a change in the magnetic flux density acting on the two magnetic flux collecting yokes 41, and outputs the detected change in magnetic flux density as an electric signal from the connection terminal 43. This enables the magnetic flux collecting yoke assembly 40 to convert the change in magnetic flux density acting on the two magnetic flux collecting yokes 41 into an electric signal by the Hall IC 42 and output it from the connection terminal 43 to the ECU 90.

[0064] Fig. 10 is a view taken along the CC arrow in Fig. 8. Fig. 11 is a cross-sectional view taken along the DD arrow in Fig. 10. A screw fastener insertion hole 52 and a positioning protrusion 55 are formed in the flanges 51 formed on both sides of the body 50 in the width direction of the body 50. The screw fastener insertion hole 52 and the positioning protrusion 55 are formed in each of the flanges 51 formed on both sides of the body 50, so that a plurality of screw fastener insertion holes 52 and a plurality of positioning protrusions 55 are formed in the magnetic collecting yoke assembly 40. In this embodiment, one screw fastener insertion hole 52 and one positioning protrusion 55 are formed in each of the flanges 51 on both sides of the body 50, so that two screw fastener insertion holes 52 and two positioning protrusions 55 are formed in each magnetic collecting yoke assembly 40.

[0065] The screw fastener insertion hole 52 is a hole that penetrates the flange 51 in the thickness direction of the flange 51, and is formed as a hole through which a screw fastener 70 (see Figure 3) used to attach the magnetic flux collector yoke assembly 40 to the column housing 10 passes.

[0066] The positioning protrusion 55 is located around the screw fastener insertion hole 52 and is a portion that protrudes from the surface of the flange 51 on the side that is attached to the column housing 10. More specifically, the positioning protrusion 55 is formed integrally with the flange 51 and is formed to protrude in the thickness direction of the flange 51 from the surface of the flange 51 on the side that is attached to the column housing 10, i.e., the surface on the side where the magnetic flux collecting yoke 41 is located in the thickness direction of the flange 51. In this embodiment, the positioning protrusion 55 is molded integrally with the flange 51 using, for example, a resin material, and the flange 51 is molded integrally with the body 50. The positioning protrusion 55 is formed to protrude in a substantially cylindrical shape whose axis coincides with the axis of the screw fastener insertion hole 52.

[0067] Further, a metal bush 60 made of a metal material and formed in a substantially cylindrical shape is disposed in the flange 51. The metal bush 60 is disposed in both of the flanges 51 formed on both sides of the body 50. The metal bush 60 has a flange 61 formed in an annular shape at one end of the cylinder, which protrudes outward in the radial direction of the cylinder. The length of the metal bush 60 is slightly longer than the length from the surface of the flange 51 opposite to the side where the positioning protrusion 55 is located to the tip of the positioning protrusion 55. The metal bush 60 thus formed is disposed at a position where the screw fastener insertion hole 52 is formed in the flange 51.

[0068] In detail, the metal bushing 60 is embedded in the flange 51 at a position that forms the screw fastener insertion hole 52, with the side where the flange 51 has the flange portion 61 positioned on the opposite side to the side where the positioning protrusion 55 is positioned, and with the axis of the cylinder oriented in the thickness direction of the flange 51. Therefore, the screw fastener insertion hole 52 formed in the flange 51 is defined by the inner circumferential surface 62 of the metal bushing 60 that is formed in a substantially cylindrical shape.

[0069] In this way, the outer circumferential surface 63 of the metal bush 60 that is embedded in the flange 51 has an uneven portion 64 with repeated unevenness. The uneven portion 64 is formed, for example, by a so-called knurling process in which relatively fine unevenness is formed in a mesh pattern. The uneven portion 64 is formed over one circumference of the outer circumferential surface 63 of the metal bush 60 in a predetermined range in the length direction of the metal bush 60.

[0070] Further, the positioning protrusion 55 is formed with a protrusion 57 protruding from the outer circumferential surface 56. The protrusion 57 is formed to extend in a direction along the axial direction of the cylinder which is the shape of the positioning protrusion 55, and is formed from the end of the positioning protrusion 55 on the flange 51 side to the end on the opposite side to the side where the flange 51 is located.

[0071] Moreover, the shape of the protrusion 57 is formed in an arc shape when viewed in the extending direction of the protrusion 57. In other words, the shape of the protrusion 57 is formed in a substantially semicircular shape when viewed in the axial direction of the positioning protrusion 55, which is convex toward the outside in the radial direction of the positioning protrusion 55.

[0072] A plurality of protrusions 57 formed in this manner are disposed on one positioning protrusion 55. The plurality of protrusions 57 disposed on one positioning protrusion 55 are disposed at equal intervals in the circumferential direction of the cylinder which is the shape of the positioning protrusion 55. In this embodiment, three protrusions 57 are disposed on one positioning protrusion 55 at equal intervals.

[0073] Fig. 12 is a detailed view of the sensor installation part 20 formed in the column housing 10 shown in Fig. 3. Fig. 13 is a cross-sectional view at a position passing through two screw holes 27 in the sensor installation part 20 shown in Fig. 12. The sensor installation part 20 formed in the column housing 10 has a housing insertion hole 22, a positioning recess 25, and a screw hole 27. The sensor installation part 20 is formed on a plane parallel to the axial direction of the housing part 11 of the column housing 10.

[0074] The housing insertion hole 22 opens to the sensor installation part 20 and is a hole that communicates between the outside and inside of the housing part 11 of the column housing 10. In this way, the housing insertion hole 22 formed in the sensor installation part 20 is a portion into which the magnetic flux collection yoke 41 exposed from the body 50 is inserted from the outside of the column housing 10 to the inside of the column housing 10 when the magnetic flux collection yoke assembly 40 is attached to the sensor installation part 20.

[0075] In addition, when the magnetic flux collecting yoke assembly 40 is attached to the sensor installation section 20, the part of the body 50 close to the magnetic flux collecting yoke 41 is also inserted into the housing insertion hole 22 together with the magnetic flux collecting yoke 41. For this reason, the housing insertion hole 22 is formed in a substantially rectangular shape with the axis direction of the housing section 11 of the column housing 10 being the direction of the short side. In other words, the housing insertion hole 22 is a substantially rectangular hole with the long side being slightly longer than the length in the width direction of the body 50 of the magnetic flux collecting yoke assembly 40 and the short side being slightly longer than the length in the thickness direction of the body 50 of the magnetic flux collecting yoke assembly 40. As a result, when the magnetic flux collecting yoke assembly 40 is attached to the sensor installation section 20, the body 50 of the magnetic flux collecting yoke assembly 40 can be inserted into the housing insertion hole 22.

[0076] The housing insertion hole 22 is formed with a sufficient size relative to the body 50 so that the body 50 can be easily inserted. For this reason, it is preferable to use a dust guard or the like around the housing insertion hole 22 to prevent dust and the like from entering the column housing 10 through the housing insertion hole 22.

[0077] The positioning recesses 25 are recessed from the sensor installation section 20 at positions on both sides of the housing insertion hole 22 in the longitudinal direction of the housing insertion hole 22, and serve as portions into which the positioning protrusions 55 of the magnetic flux collecting yoke assembly 40 are inserted when the magnetic flux collecting yoke assembly 40 is attached to the sensor installation section 20. The two positioning recesses 25 arranged on both sides of the housing insertion hole 22 are formed at an interval corresponding to the two positioning protrusions 55 provided on the flange 51 of the magnetic flux collecting yoke assembly 40.

[0078] In detail, the positioning recess 25 is formed as a bottomed hole having a substantially cylindrical shape oriented such that the normal direction to the plane of the sensor installation section 20 is the axial direction. The cylindrical shape of the positioning recess 25 has a diameter approximately equal to the outer diameter of the positioning protrusion 55 of the magnetic flux collecting yoke assembly 40, and a depth approximately equal to the length from the end of the positioning protrusion 55 on the flange 51 side to the end on the opposite side of the flange 51. In this way, the positioning recess 25 is formed to have a size approximately equal to that of the positioning protrusion 55, so that when the positioning protrusion 55 is inserted into the positioning recess 25, at least a part of the positioning protrusion 55 is sized to contact the inner peripheral surface of the positioning recess 25.

[0079] The screw holes 27 are formed in the bottoms 26 of the multiple positioning recesses 25 formed in the sensor installation section 20. The screw holes 27 are sized to receive the screw fasteners 70 that pass through the screw fastener insertion holes 52 formed in the flanges 51 of the magnetic flux collecting yoke assembly 40 when the magnetic flux collecting yoke assembly 40 is attached to the sensor installation section 20 by the screw fasteners 70. The screw holes 27 are formed at positions where their axis substantially coincides with an extension of the axis of the cylindrical shape of the positioning recesses 25.

[0080] Here, we will explain the machining of the positioning recess 25 and the screw hole 27 thus formed in the column housing 10. The screw hole 27 is formed in the bottom 26 of the positioning recess 25, and is formed at a position where its axis coincides with the axis of the positioning recess 25. For this reason, when machining the column housing 10 to form the positioning recess 25 and the screw hole 27, it is preferable to perform the machining using a special tool in which tools for drilling holes, such as drills, having different diameters are formed on the same axis.

[0081] In other words, it is preferable to use a tool having a size suitable for machining the positioning recess 25 and the screw hole 27, which is integrally formed with a tool having a size suitable for machining the positioning recess 25 at the tip side. By using such a tool to machine the position of the sensor installation part 20 of the column housing 10, the positioning recess 25 is machined at the part of the tool for machining the positioning recess 25, and at the same time, a pilot hole for the screw hole 27 is machined at the part of the tool for machining the pilot hole. Thereafter, the pilot hole for the screw hole 27 is formed by tapping the pilot hole for the screw hole 27, and the part of the positioning recess 25 is finished using an end mill, a reamer, or the like, as necessary.

[0082] Next, the attachment of the magnetism collecting yoke assembly 40 to the column housing 10 will be described. Fig. 14 is an explanatory diagram showing the magnetism collecting yoke assembly 40 attached to the column housing 10. When attaching the magnetism collecting yoke assembly 40 to the sensor installation section 20 of the column housing 10, the body 50 of the magnetism collecting yoke assembly 40 is inserted into the housing insertion hole 22 in a direction such that the magnetism collecting yoke assembly 40 is inserted into the housing insertion hole 22 of the sensor installation section 20 from the side where the magnetism collecting yoke 41 exposed from the body 50 is located.

[0083] When the body 50 is inserted into the housing insertion hole 22 and the positioning protrusions 55 provided on the flanges 51 arranged on both sides of the body 50 reach the positions of the positioning recesses 25 formed in the sensor installation section 20, the positioning protrusions 55 are inserted into the positioning recesses 25. That is, the positioning protrusions 55 provided on the flanges 51 extend in the insertion direction of the positioning protrusions 55 into the positioning recesses 25, and the two positioning protrusions 55 arranged on both sides of the body 50 are spaced the same distance apart as the two positioning recesses 25 formed on both sides of the sensor installation section 20, so that both of the two positioning protrusions 55 are inserted into the two positioning recesses 25.

[0084] At this time, the positioning protrusions 55 and the positioning recesses 25 have approximately the same diameter, and since the positioning protrusions 55 are made of a resin material, they have a certain degree of elasticity. Therefore, when the positioning protrusions 55 are inserted into the positioning recesses 25, the positioning protrusions 55 are lightly press-fitted into the positioning recesses 25. That is, at least a part of the outer circumferential surface of the positioning protrusions 55 contacts the inner circumferential surface of the positioning recesses 25, and the positioning protrusions 55 are inserted in a slightly compressed state due to the pressure from the positioning recesses 25.

[0085] Furthermore, since the positioning protrusion 55 has a protrusion 57 protruding from the outer circumferential surface 56, the protrusion 57 is likely to come into contact with the positioning recess 25, and since the protrusion 57 has a small volume, it is likely to be elastically deformed. As a result, when the positioning protrusion 55 is inserted into the positioning recess 25, the protrusion 57 comes into contact with the inner circumferential surface of the positioning recess 25, causing the protrusion 57 to elastically deform, and the contact pressure of the positioning protrusion 55 against the positioning recess 25 increases due to the elastic deformation of the protrusion 57. Therefore, the positioning protrusion 55 is lightly press-fitted into the positioning recess 25 also by this action.

[0086] Fig. 15 is an E-E cross-sectional view of Fig. 14. After the positioning protrusion 55 is inserted into the positioning recess 25, a screw fastener 70 is passed through a screw fastener insertion hole 52 provided in a flange 51 of the magnetic flux collecting yoke assembly 40, and the screw fastener 70 is screwed into a screw hole 27 formed in a bottom portion 26 of the positioning recess 25. In detail, the screw hole 27 is passed through the screw fastener insertion hole 52 formed by an inner peripheral surface 62 of a metal bush 60 provided in the flange 51, and screwed into the screw hole 27. As a result, the magnetic flux collecting yoke assembly 40 is attached to the column housing 10 with the metal bush 60 provided in the flange 51 pressed against the bottom portion 26 of the positioning recess 25 by the screw hole 27.

[0087] When the magnetic flux collecting yoke assembly 40 is attached to the column housing 10, at least a part of the positioning protrusion 55 provided on the flange 51 of the magnetic flux collecting yoke assembly 40 is inserted while being in contact with the positioning recess 25 formed in the sensor installation portion 20 of the column housing 10. This allows the magnetic flux collecting yoke assembly 40 to be attached to the column housing 10 without variation. Therefore, the magnetic flux collecting yoke 41 of the magnetic flux collecting yoke assembly 40 can be positioned at a desired position in the column housing 10. This allows the clearance g (see FIG. 7) between the magnetic flux collecting yoke 41 in the column housing 10 and the ring portion 31 of the stator 30 to be as designed.

[0088] As described above, in the torque sensor 1 according to this embodiment, the screw fastener insertion hole 52 and the positioning protrusion 55 are formed in the flange 51 of the magnetic flux collecting yoke assembly 40, and the positioning recess 25 and the screw hole 27 are formed in the sensor installation section 20 of the column housing 10. Among these, the positioning recess 25 is configured so that the positioning protrusion 55 is inserted and at least a part of the positioning protrusion 55 comes into contact with the screw fastener insertion hole 52, and the screw hole 27 is configured so that the screw fastener 70 passing through the screw fastener insertion hole 52 is screwed into the screw fastener insertion hole 52. As a result, in the torque sensor 1 in which the magnetic flux collecting yoke assembly 40 is attached to the column housing 10 by the screw fastener 70, the positioning accuracy can be improved only by the positioning protrusion 55 and the positioning recess 25 without performing high-precision machining over a wide area to improve the positioning accuracy between the stator 30 and the magnetic flux collecting yoke 41. As a result, the positioning accuracy can be improved while suppressing an increase in manufacturing cost.

[0089] In addition, since the positioning protrusion 55 is lightly press-fitted into the positioning recess 25, it is possible to further improve the positioning accuracy when attaching the magnetic flux collecting yoke assembly 40 to the column housing 10. As a result, it is possible to improve the positioning accuracy while suppressing an increase in manufacturing costs.

[0090] Furthermore, since the positioning protrusion 55 is formed with a protrusion 57 that extends in the insertion direction of the positioning protrusion 55 into the positioning recess 25 and protrudes from the outer circumferential surface 56 of the positioning protrusion 55, when the positioning protrusion 55 is inserted into the positioning recess 25, the protrusion 57 can be inserted while contacting the inner circumferential surface of the positioning recess 25. This can further improve the positioning accuracy using the positioning protrusion 55 and the positioning recess 25. As a result, the positioning accuracy can be improved while suppressing an increase in manufacturing costs.

[0091] Moreover, since the protrusion 57 is formed in an arc shape when viewed in the extending direction of the protrusion 57, the positioning accuracy using the positioning convex portion 55 and the positioning concave portion 25 is improved by the protrusion 57, and the positioning convex portion 55 can be smoothly inserted into the positioning concave portion 25. As a result, the magnetic flux collecting yoke assembly 40 can be easily attached to the column housing 10, and the positioning accuracy can be improved while suppressing an increase in manufacturing costs.

[0092] Furthermore, since the metal bush 60 is disposed in the flange 51 and the screw fastener insertion hole 52 is formed by the inner peripheral surface 62 of the metal bush 60, the positioning accuracy can be improved by the positioning protrusion 55 and the positioning recess 25, while the strength can be ensured when the magnetic flux collecting yoke assembly 40 is attached to the column housing 10 by the screw fastener 70. As a result, the positioning accuracy can be improved while suppressing an increase in manufacturing costs.

[0093] Furthermore, since the outer peripheral surface 63 of the metal bushing 60 is formed with an uneven portion 64 having repeated unevenness, it is possible to increase the degree of adhesion between the flange 51 and the metal bushing 60, and to prevent the metal bushing 60 from coming off the flange 51. As a result, it is possible to improve the positioning accuracy while suppressing an increase in manufacturing costs.

[0094] Furthermore, in the manufacturing method of the torque sensor 1 according to this embodiment, since the pilot hole for the screw hole 27 is machined at the same time as the positioning recess 25 is machined in the sensor installation portion 20 of the column housing 10, it is possible to reduce the number of work steps for forming the positioning recess 25 and the screw hole 27. As a result, it is possible to improve the positioning accuracy while suppressing an increase in manufacturing costs.

[0095] [Variations] In the torque sensor 1 according to the embodiment described above, the metal bush 60 is prevented from coming off from the flange 51 by forming the uneven portion 64 on the outer circumferential surface 63, but the metal bush 60 may be prevented from coming off by a means other than the uneven portion 64. FIG. 16 is a modified example of the torque sensor 1 according to the embodiment, and is an explanatory diagram of a case where a slit 65 is formed in the metal bush 60. For example, as shown in FIG. 16, the metal bush 60 may have a slit 65 formed from one end side to the other end side in the axial direction of the metal bush 60, the slit 65 being inclined with respect to the axial direction. When the slit 65 is formed in the metal bush 60, the edge of the slit 65 gets caught on the flange 51, and the slit 65 generates a force that resists the movement of the metal bush 60 to come off from the flange 51 in the axial direction. This makes it difficult for the metal bush 60 to come off from the flange 51.

[0096] Furthermore, by forming the slits 65 in the metal bushing 60, the metal bushing 60 can have elasticity that acts in a direction in which the width of the slits 65 increases. As a result, the metal bushing 60 placed on the flange 51 can apply a force to the flange 51 in a direction in which the width of the slits 65 increases and the metal bushing 60 comes into close contact with the flange 51. This also makes it difficult for the metal bushing 60 to come off the flange 51. As a result, it is possible to prevent the metal bushing 60 from coming off the flange 51, and it is possible to improve the positioning accuracy while suppressing an increase in manufacturing costs.

[0097] In the torque sensor 1 according to the embodiment described above, the protrusion 57 formed on the positioning protrusion 55 of the magnetic flux collecting yoke assembly 40 is formed in an arc shape, but the protrusion 57 may be formed in a shape other than an arc shape. FIG. 17 is a modified example of the torque sensor 1 according to the embodiment, and is an explanatory diagram of a case where the protrusion 57 is formed in a rectangular shape. FIG. 18 is a modified example of the torque sensor 1 according to the embodiment, and is an explanatory diagram of a case where the protrusion 57 has an edge portion 58. The protrusion 57 formed on the outer peripheral surface 56 of the positioning protrusion 55 may be formed in a rectangular shape as shown in FIG. 17, or may be formed in a shape having an edge portion 58 that is convex on the radially outer side of the positioning protrusion 55 as shown in FIG. 18. The protrusion 57 is preferably formed in a shape that allows the positioning protrusion 55 to be lightly pressed into the positioning recess 25 depending on the relative size between the outer diameter of the positioning protrusion 55 and the inner diameter of the positioning recess 25, the material of the positioning protrusion 55 and the column housing 10, and the like.

[0098] In the torque sensor 1 according to the embodiment described above, three protrusions 57 are arranged on the positioning protrusion 55, but the number of protrusions 57 arranged on the positioning protrusion 55 may be other than three. The number of protrusions 57 arranged on the positioning protrusion 55 is not important as long as multiple protrusions 57 are arranged at equal intervals in the circumferential direction of the cylinder that is the shape of the positioning protrusion 55.

[0099] Moreover, the protrusions 57 arranged on the positioning protrusions 55 may be arranged in different numbers for the positioning protrusions 55. FIG. 19 is a modified example of the torque sensor 1 according to the embodiment, and is an explanatory diagram of a case where the number of protrusions 57 is different for the positioning protrusions 55. The positioning protrusions 55 are provided on each of the flanges 51 formed on both sides of the body 50 of the magnetic flux collecting yoke assembly 40, and the protrusions 57 protruding from the outer circumferential surface 56 of the positioning protrusions 55 may be different for each positioning protrusion 55. For example, as shown in FIG. 19, three protrusions 57 may be arranged on the positioning protrusion 55 provided on one of the two flanges 51, and two protrusions 57 may be arranged on the positioning protrusion 55 provided on the other flange 51.

[0100] In addition, when two protrusions 57 are arranged, the protrusions 57 can be arranged so as to be aligned along the axial direction of the stator 30. By arranging the protrusions 57 so as to be aligned along the axial direction of the stator 30, the protrusions 57 arranged along the axial direction can be abutted against the column housing 10, so that the magnetic flux collecting yoke assembly 40 can be prevented from moving in the axial direction. By preventing the magnetic flux collecting yoke assembly 40 from moving in the axial direction, the relative position between the stator 30 and the magnetic flux collecting yoke assembly 40 can be prevented from changing, so that the output of the torque sensor 1 can be prevented from fluctuating. In other words, when two protrusions 57 are arranged, the protrusions 57 can be arranged so as to be aligned along the axial direction of the stator 30, so that the output of the torque sensor 1 can be prevented from fluctuating.

[0101] By making the number of protrusions 57 different between the positioning protrusions 55, the positioning protrusion 55 with more protrusions 57 can be inserted into the positioning recess 25 with high positional accuracy, while the positioning protrusion 55 with fewer protrusions 57 can be inserted into the positioning recess 25 with a certain degree of tolerance for relative misalignment. As a result, even if a slight dimensional error occurs when forming the positioning protrusions 55 and the positioning recess 25, the magnetic flux collecting yoke assembly 40 can be attached to the column housing 10 while ensuring positioning accuracy and absorbing the dimensional error.

[0102] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments. The configurations described as the embodiments and modified examples may be combined as appropriate. [Explanation of symbols]

[0103] 1 Torque Sensor 10 Column housing 11 Housing 20 Sensor installation section 22 Housing insertion hole 25 Positioning recess 26 Bottom 27 Screw hole 30 Stator 35 Magnet 40 Magnetic collector yoke assembly 41 Magnetic field collector yoke 42 Hall IC 50 Body 51 Flange 52 Screw fastener insertion hole 55 Positioning protrusion 56, 63 Outer surface 57 Protrusion 58 Edge 60 Metal bush 62 Inner surface 64 Uneven part 65 Slit 70 Screw fasteners 80 Steering device

Claims

1. A torque sensor comprising: a housing in which a stator is disposed; a cylindrical magnet disposed facing the stator; and a magnetic flux collecting yoke assembly including a magnetic flux collecting yoke for detecting a change in magnetic flux corresponding to a relative positional change between the stator and the cylindrical magnet, the magnetic flux collecting yoke assembly includes a body that holds the magnetic flux collecting yoke while exposing it, and a flange that protrudes from the body; the flange is formed with a plurality of screw fastener insertion holes through which screw fasteners used to attach the magnetic flux collecting yoke assembly to the housing pass, and a plurality of positioning protrusions are formed around the screw fastener insertion holes and protrude from a surface of the flange on a side that is attached to the housing, the housing has a sensor installation portion to which the magnetic flux collecting yoke assembly is attached, The torque sensor is provided with a housing insertion hole in the sensor mounting portion, through which the magnetic collecting yoke exposed from the body is inserted from the outside of the housing to the inside of the housing, a plurality of positioning recesses formed recessed from the sensor mounting portion, into which the positioning protrusions are inserted and into which at least a portion of the positioning protrusions come into contact, and a plurality of screw holes formed in the bottom of the positioning recesses, into which the screw fasteners that have passed through the screw fastener insertion holes formed in the flange are screwed.

2. The positioning protrusion is lightly press-fitted into the positioning recess. The torque sensor according to claim 1 .

3. The positioning protrusion has a protrusion extending in an insertion direction of the positioning protrusion into the positioning recess and protruding from an outer circumferential surface of the positioning protrusion. The torque sensor according to claim 1 or 2.

4. The protrusion is formed to have an arc-like shape when viewed in the extending direction of the protrusion. The torque sensor according to claim 3.

5. The protrusion is formed in a rectangular shape when viewed in the extending direction of the protrusion. The torque sensor according to claim 3.

6. The protrusion is formed in a shape having an edge portion when viewed in the extending direction of the protrusion. The torque sensor according to claim 3.

7. The protrusions are arranged in different numbers on the positioning protrusions. The torque sensor according to any one of claims 3 to 6.

8. A metal bush formed in a substantially cylindrical shape is disposed on the flange, The threaded fastener insertion hole is formed by an inner peripheral surface of the metal bush. The torque sensor according to claim 1 .

9. The metal bush has an outer circumferential surface on which a concave-convex portion is formed. The torque sensor according to claim 8.

10. The metal bush has a slit inclined with respect to the axial direction. The torque sensor according to claim 8.

11. A method for manufacturing a torque sensor including a housing in which a stator is disposed, a cylindrical magnet disposed facing the stator, and a magnetic flux collecting yoke assembly including a magnetic flux collecting yoke for detecting a change in magnetic flux corresponding to a relative positional change between the stator and the cylindrical magnet, comprising: the magnetic flux collecting yoke assembly includes a body that holds the magnetic flux collecting yoke while exposing it, and a flange that protrudes from the body; the flange is formed with a plurality of screw fastener insertion holes through which screw fasteners used to attach the magnetic flux collecting yoke assembly to the housing pass, and a plurality of positioning protrusions are formed around the screw fastener insertion holes and protrude from a surface of the flange on a side that is attached to the housing, the housing has a sensor installation portion to which the magnetic flux collecting yoke assembly is attached, In the torque sensor, the sensor installation portion is provided with a housing insertion hole into which the magnetic flux collecting yoke exposed from the body is inserted from the outside of the housing to the inside of the housing, a plurality of positioning recesses formed in the sensor installation portion and into which the positioning protrusions are inserted and into which at least a portion of the positioning protrusions come into contact, and a plurality of screw holes formed in bottoms of the positioning recesses and into which the screw fasteners passing through the screw fastener insertion holes formed in the flange are screwed, A method for manufacturing a torque sensor, comprising machining the positioning recess and machining a pilot hole for the screw hole at the same time.

Images