JP2021012218A - Torque detector and magnetic sensor module - Google Patents

Abstract

To provide a torque detector capable of improving an SN ratio of a magnetic flux detected by a magnetic sensor.SOLUTION: One set of magnetic flux induction members 512 and 522 are formed of soft magnetic materials, and one set of yokes 31 and 32 and a main body 60 face each other and induce a magnetic flux of a magnetic circuit. Magnetic sensors 71 and 72 are installed on an extension contact part 61 and 62, and detect the magnetic flux induced by the magnetic flux induction members 512 and 522. The magnetic flux induction members 512 and 522 are configured such that, on a branch part to the extension contact part 61 and 62 on the main body 60, a magnetic permeance for a unit area between the magnetic flux induction member 512 and 522 and the yoke 31 and 32 is larger than that on a peripheral edge part. The main bodies of the magnetic flux induction members 512 and 522 are symmetric to a reference line X, and are formed into a belt shape whose center is a point Q being provided on an opposite side of the magnetic sensors 71 and 72 with respect to a center shaft O of the yoke on the reference line X, and whose opposite sides are concentric circular arcs having a curvature smaller than that of a circular arc whose center is the center shaft O of the yoke.SELECTED DRAWING: Figure 7

Description

The present invention relates to a torque detection device and a magnetic sensor module used in the torque detection device.

Conventionally, there is known a torque detection device that detects a change in magnetic flux caused by the relative rotation of a multi-pole magnet and a yoke with a magnetic sensor and detects torque applied to a torsion bar based on an output signal of the magnetic sensor. Further, in this type of torque detecting device, a configuration using a magnetic flux guiding member that collects the magnetic flux of the yoke and guides it to the magnetic sensor is known.

For example, in the configuration disclosed in Patent Document 1, in the magnetic collecting ring corresponding to the magnetic flux guiding member, the distance from the central axis of the multipolar magnet (or yoke) to the inner edge of the magnetic collecting ring is the multipolar magnet (or yoke). ) Is formed so as to be maximum in the direction connecting the central axis and the magnetic sensor. As a result, the periodic fluctuation of the magnetic flux generated in the magnetic circuit when the multi-pole magnet and the yoke rotate in synchronization with the torque being constant is suppressed. Hereinafter, in the present specification, the noise due to the periodic fluctuation of the magnetic flux is referred to as "swing noise".

Japanese Unexamined Patent Publication No. 2012-237727

In this type of torque detection device, since the output voltage of the magnetic sensor is amplified by the amplifier and transmitted to the control device, it is important to improve the SN ratio by increasing the signal and reducing the noise. However, in the configuration of Patent Document 1, the area where the magnetic flux guiding member and the yoke face each other in the axial direction becomes relatively small in a portion near the magnetic sensor, and depending on the embodiment, the facing area between the magnetic flux guiding member and the yoke becomes relatively small. It is 0. Therefore, when the magnetic flux guiding member and the yoke are opposed to each other at a portion away from the magnetic sensor to collect the magnetic flux, the magnetic resistance is higher than when the magnetic flux is collected near the magnetic sensor, so that the amount of magnetic flux collected by the sensor is reduced. Therefore, there is a problem that the SN ratio cannot be expected to be improved because the swing noise becomes smaller and the signal becomes smaller.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a torque detection device for improving the SN ratio of magnetic flux detected by a magnetic sensor, and a magnetic sensor module used for the torque detection device. To do.

The torque detection device of the present invention includes a torsion bar (13), a multi-pole magnet (14), a set of yokes (31, 32), and one or more magnetic flux guiding members (512, 522). The above magnetic sensors (71, 72) are provided. The torsion bar coaxially connects the first axis (11) and the second axis (12), and converts the torque applied between the first axis and the second axis into torsional displacement. The multi-pole magnet is fixed to the first axis or one end side of the torsion bar, and the north and south poles are alternately arranged in the circumferential direction. A set of yokes is made of a soft magnetic material, fixed to the second axis or the other end of the torsion bar on the outer diameter of the multipolar magnet, facing each other in the axial direction, and a magnetic circuit in the magnetic field of the multipolar magnet. To form.

The magnetic flux guiding member is made of a soft magnetic material, and at least one yoke and the main body (60) face each other to induce the magnetic flux of the magnetic circuit. The magnetic sensor is installed in the main body of the magnetic flux guiding member or the extension portions (61, 62) branched from the main body, and detects the magnetic flux induced by the magnetic flux guiding member. Here, in the axial projection of the yoke, when there is one magnetic sensor, the magnetic sensor and the central axis of the yoke are connected, and when there are a plurality of magnetic sensors, the intermediate position of the plurality of magnetic sensors and the central axis of the yoke are connected. Let the connecting virtual straight line be the reference line (X). Further, the portions corresponding to both ends in the circumferential direction of the yoke in the range facing the main body of the magnetic flux guiding member and the yoke with the reference line sandwiched are defined as the peripheral ends (63, 64) of the main body of the magnetic flux guiding member.

The magnetic flux guiding member is a branching part to the installation part or the extension part of the magnetic sensor in the main body, so that the "magnetic permeance per unit area between the magnetic flux guiding member and the yoke" is larger than that of the peripheral end part. It is configured.

The main body of the magnetic flux induction member is an arc centered on a point symmetrical with respect to the reference line and located on the reference line on the side opposite to the magnetic sensor with respect to the central axis of the yoke, and centered on the central axis of the yoke. It is formed in a band shape with concentric arcs having a smaller curvature as opposite sides. As a result, the signal detected by the magnetic sensor becomes large, so that the SN ratio can be improved.

In this configuration, the distance from the magnetic sensor installation portion or the branch portion to the extension portion in the main body of the magnetic flux induction member to the central axis of the yoke is shorter than the distance from the peripheral end portion to the central axis of the yoke.

Further, in the configuration in which the torque detection device includes two magnetic sensors arranged symmetrically with respect to the reference line, the magnetic flux branches from the reference line side of the magnetic flux guiding member toward the two magnetic sensors, so that the magnetic sensor becomes a magnetic sensor. It is thought that the propagated noise is reduced. As a result, the SN ratio of the magnetic flux detected by the magnetic sensor can be further improved.

The present invention is also used in the torque detection device described above, and is provided as a magnetic sensor module in which a magnetic flux induction member and a magnetic sensor are integrally configured. For example, the magnetic sensor module is integrally resin-molded. This magnetic sensor module can be independently manufactured and sold as a component constituting the torque detection device, and has an effect of improving the SN ratio when used in the torque detection device.

An exploded perspective view of the torque detection device according to each embodiment (the magnetic sensor module is the first embodiment). The schematic block diagram of the electric power steering apparatus to which the torque detection apparatus of each embodiment is applied. (A) plan view, (b) side view of the magnetic sensor module of the first embodiment. FIG. 3 is an axial sectional view of the magnetic sensor module of the first embodiment. (A) A correlation diagram between a distance from a reference line and a magnetic permeance in the first embodiment, and (b) a diagram for explaining reduction of swing fluctuation according to the first embodiment. The figure explaining the improvement of the manufacturing yield by the magnetic flux induction member of 1st Embodiment. The plan view of the magnetic sensor module of the 2nd Embodiment. (A) plan view, (b) side view of the magnetic sensor module of the third embodiment. (A) plan view, (b) side view of the magnetic sensor module of the fourth embodiment. FIG. 3 is an axial sectional view of the magnetic sensor module of the fourth embodiment. FIG. 5 is an axial sectional view of the magnetic sensor module of the fifth embodiment. FIG. 6 is an axial sectional view of the magnetic sensor module of the sixth embodiment. (A) plan view and (b) side view of the magnetic sensor module and yoke of the seventh embodiment. FIG. 6 is an axial sectional view of the magnetic sensor module and the yoke of the seventh embodiment. (A) plan view, (b) side view of the magnetic sensor module of the eighth embodiment. The plan view of the magnetic sensor module of the 9th Embodiment. (A) plan view, (b) side view of the magnetic sensor module of the tenth embodiment. The correlation diagram between the distance from the reference line and the magnetic permeance in the tenth embodiment. The plan view of the magnetic sensor module of 11th Embodiment. The plan view of the magnetic sensor module of the twelfth embodiment. (A) plan view and (b) axial sectional view of the magnetic sensor module of the thirteenth embodiment. (A) plan view and (b) axial sectional view of the magnetic sensor module of the 14th embodiment. (A) plan view and (b) partial perspective view of the yoke of other embodiments. Reference diagram showing the flow of magnetic flux from the claws of the yoke to the ring.

Hereinafter, a plurality of embodiments of the torque detection device will be described with reference to the drawings. In a plurality of embodiments, substantially the same configurations are designated by the same reference numerals and description thereof will be omitted.
Of the following first to fourth embodiments, the second embodiment and the embodiment that can be combined with the second embodiment correspond to "the embodiment for carrying out the invention described in the claims". , Other than that, it corresponds to the reference form.
The torque detection device of the present embodiment is applied to an electric power steering device for assisting the steering operation of the vehicle.

First, with reference to FIG. 2, a schematic configuration of an electric power steering device to which the torque detection device of each embodiment is applied will be described. Although the electric power steering device 90 shown in FIG. 2 is a column assist type, it can be similarly applied to a rack assist type electric power steering device. A torque detection device 10 for detecting steering torque is installed on the steering shaft 94 connected to the steering wheel 93. A pinion gear 96 is provided at the tip of the steering shaft 94, and the pinion gear 96 meshes with the rack shaft 97. A pair of wheels 98 are rotatably connected to both ends of the rack shaft 97 via a tie rod or the like. The rotational motion of the steering shaft 94 is converted into a linear motion of the rack shaft 97 by the pinion gear 96, and the pair of wheels 98 are steered.

The torque detection device 10 is provided between the input shaft 11 and the output shaft 12 constituting the steering shaft 94, detects the steering torque applied to the steering shaft 94, and outputs the torque to the ECU 91. The ECU 91 controls the output of the motor 92 according to the detected steering torque. The steering assist torque generated by the motor 92 is decelerated via the reduction gear 95 and transmitted to the steering shaft 94.

Here, the mode in which the torque detection device 10 includes two magnetic sensors 71 and 72 and outputs two values trq1 and trq2 as steering torque corresponds to the first to tenth embodiments. By configuring the torque information used for controlling the ECU 91 to be redundantly output, even if one torque information becomes unusable due to a failure of the magnetic sensor or the arithmetic circuit, the ECU 91 uses the other torque information to make the motor 92. Can continue to drive. Therefore, such a redundant configuration is particularly effective in the electric power steering device 90, which requires high reliability. However, as in the eleventh and twelfth embodiments, the torque detection device 10 may be configured to include one magnetic sensor 71.

Next, the overall configuration of the torque detection device 10 will be described with reference to FIGS. 1 and 2. As shown in FIG. 2, the torque detection device 10 includes a torsion bar 13, a multi-pole magnet 14, a set of yokes 31, 32, one or more magnetic flux guiding members 51, 52, and one or more magnetic sensors 71. , 72 and the like. Further, a unit including one or more magnetic flux guiding members 51 and 52 and one or more magnetic sensors 71 and 72 is referred to as a magnetic sensor module 50.

Here, in FIG. 2, which schematically shows the shapes of the constituent members, “50” is used as a code that includes the magnetic sensor module of each embodiment, and “51, 52” is used as a code that includes the magnetic flux induction member of each embodiment. Is used. On the other hand, in FIG. 1, which specifically represents the shape of the magnetic flux guiding member of the first embodiment, the reference numeral "501" of the magnetic sensor module of the first embodiment and the reference numeral "511" of the magnetic flux guiding member of the first embodiment are shown. 521 ”is used. As described above, the specific shapes of the magnetic flux guiding members 51 and 52 and the number of magnetic sensors 71 and 72 are different in each embodiment. However, in the description in this portion, the detailed shape of the magnetic flux guiding members 511 and 521 in FIG. 1 is not referred to, and only the overall configuration of the torque detecting device 10 is referred to.

As shown in FIGS. 1 and 2, the torsion bar 13 is fixed to the input shaft 11 as the "first axis" on one end side and to the output shaft 12 as the "second axis" on the other end side by fixing pins 15. Then, the input shaft 11 and the output shaft 12 are connected on the same axis as the central shaft O. The torsion bar 13 is a rod-shaped elastic member, and converts the steering torque applied to the steering shaft 94 into a torsional displacement. The multi-pole magnet 14 is fixed to the input shaft 11, and the north and south poles are alternately arranged in the circumferential direction. In this embodiment, the north pole and the south pole are each arranged at 8 poles, and a total of 16 poles are arranged at 22.5 ° intervals.

The pair of yokes 31 and 32 are formed of a soft magnetic material in an annular shape, are fixed to the output shaft 12 on the outer diameter of the multipolar magnet 14, and face each other in the axial direction with a gap. The sets of yokes 31 and 32 have the same number of claws 33 and 34 as the north and south poles of the multi-pole magnet 14, respectively, provided at equal intervals all around the inner edge of the ring. The claw 33 of one yoke 31 and the claw 34 of the other yoke 32 are alternately arranged so as to be displaced in the circumferential direction. In this way, the pair of yokes 31 and 32 form a magnetic circuit in the magnetic field generated by the multipolar magnet 14.

When a torsional displacement is applied to the torsion bar 13, the magnetic flux passing through the magnetic circuit changes with the relative rotation of the multipolar magnet 14 and the pair of yokes 31 and 32, and the information of the rotation angle is obtained by detecting the magnetic flux. can get. The detection principle is described in FIGS. 5 and 6 of Patent Document 1 (Japanese Unexamined Patent Publication No. 2012-237727).

Since the torsion bar 13, the multipolar magnet 14, and the set of yokes 31 and 32 are coaxially configured, the central axis O may be defined with reference to any of them. In the present specification, it is basically described as "the central axis O of the yokes 31 and 32" with reference to the yokes 31 and 32 in which the facing relationship with the magnetic flux guiding members 51 and 52 is focused.

Further, in the description of the embodiment, the axial direction and the radial direction of the torsion bar 13, the multi-pole magnet 14, the set of yokes 31, 32, etc. are simply referred to as "axial direction" and "diameter direction". Further, the plan view in the description of the drawings means a view seen from the first axis 11 side in the axial direction, and the side view means a view seen from the radial direction. "In plan view" is synonymous with "in axial projection".

The magnetic flux guiding members 51 and 52 are made of a soft magnetic material, and the main body 60 faces at least one of the yokes 31 and 32 of the set of yokes 31 and 32 in the axial or radial direction, and the magnetic flux of the magnetic circuit is measured by the magnetic sensor 71. Induce to 72. In many embodiments except the 14th embodiment, a set of magnetic flux guiding members 51, 52 is provided.

Hereinafter, for convenience of explanation, the yoke 31 and the magnetic flux guiding member 51 arranged on the first shaft 11 side in FIGS. 1 and 2 are referred to as "upper yoke 31" and "upper magnetic flux guiding member 51". Further, the yoke 32 and the magnetic flux guiding member 52 arranged on the second shaft 12 side are referred to as "lower yoke 32" and "lower magnetic flux guiding member 52". The upper magnetic flux guiding member 51 faces the upper yoke 31, and the lower magnetic flux guiding member 52 faces the lower yoke 32. In many embodiments except the thirteenth embodiment, the set of yokes 31 and 32 are arranged symmetrically in the axial direction and face each other in the axial direction.

As shown in FIG. 1, one set of magnetic flux guiding members 511 and 521 of the first embodiment has two sets of extension portions 61 and 62 branched from the main body 60. Specifically, the extension portions 61 and 62 extend radially outward from the main body 60 to the yokes 31 and 32. The two magnetic sensors 71 and 72 are arranged between the extension portions 61 and 62, respectively. The extension portions 61 and 62 have a step in the axial direction so that the gap is minimized in the portion where the magnetic sensors 71 and 72 are arranged between them. For example, when the magnetic flux induction members 51 and 52 are press-formed, the steps of the extension portions 61 and 62 can be formed by bending the sheet metal or the like.

The magnetic sensors 71 and 72 detect the magnetic flux induced by the magnetic flux guiding members 51 and 52 from the set of yokes 31 and 32, convert it into a voltage signal, and output it to the external ECU 91 via the lead wires 73 and 74. To do. For example, the magnetic sensors 71 and 72 are composed of a substantially rectangular parallelepiped IC package in which Hall elements, magnetoresistive elements, and the like are resin-molded.

In the torque detection device having the above configuration, when the multipolar magnet 14 and the yokes 31 and 32 rotate in synchronization with the torque applied to the torsion bar 13 being constant, the magnetic flux passing through the magnetic circuit fluctuates periodically. .. This periodic fluctuation of the magnetic flux can be "swing noise" with respect to the output signal from the magnetic sensors 71 and 72 to the ECU 91.

Here, the swing noise will be described with reference to FIG. 24, which is a reference diagram showing the flow of magnetic flux from the claw of the yoke to the ring. The ring portion of the yokes 31 and 32 has a difference in magnetic flux density depending on the distance from the claws 33 and 34 of the yokes 31 and 32 facing the multipolar magnet 14 which is the magnetic flux source. That is, the magnetic flux density is high in the portion close to the claws 33 and 34, and the magnetic flux density is low in the portion away from the claws 33 and 34.

Therefore, when the multipolar magnet 14 and the yokes 31 and 32 rotate in synchronization, the magnetic sensor arranged at a specific position between the rings of the yokes 31 and 32 detects the fluctuation of the magnetic flux due to the rotation. .. Further, with rotation, a leakage flux leaking between the claws 33 and 34 is added, and the fluctuation of the magnetic flux becomes large. This is detected by the magnetic sensor as swinging noise. As described above, when the swing noise is relatively large compared to the signal detected by the magnetic sensor, the SN ratio is lowered.

In response to this noise, in the prior art of Patent Document 1, in the direction connecting the central axis O and the magnetic sensor, from the central axis O to the inner edge of the magnetic collecting ring (that is, the magnetic flux guiding member of the present embodiment). The shape of the magnetic collecting ring is determined so that the distance is maximized. For example, the magnetic collecting ring is formed in an elliptical arc shape having a major axis in the direction connecting the central axis O and the magnetic sensor. By moving the magnetic sensor away from the multi-pole magnet in this way, we are trying to suppress the influence of magnetic flux fluctuations on the magnetic sensor.

However, in the configuration of Patent Document 1, the area where the magnetic flux guiding member and the yoke face each other in the axial direction becomes relatively small in a portion near the magnetic sensor, and depending on the embodiment, the facing area between the magnetic flux guiding member and the yoke becomes relatively small. It is 0. Therefore, when the magnetic flux guiding member and the yoke are opposed to each other at a portion away from the magnetic sensor to collect the magnetic flux, the magnetic resistance is higher than when the magnetic flux is collected near the magnetic sensor, so that the amount of magnetic flux collected by the sensor is reduced. Therefore, there is a problem that the SN ratio cannot be expected to be improved because the swing noise becomes smaller and the signal becomes smaller.

Therefore, it is basically an object of the present embodiment to improve the SN ratio of the magnetic flux detected by the magnetic sensor by suppressing the swinging noise while increasing the signal toward the portion closer to the magnetic sensor. However, as an exception, in the tenth embodiment, the SN ratio is improved only by the noise suppressing effect without increasing the signal.

Further, in some embodiments, as a further purpose, the size of the magnetic sensor module 50 is reduced and the ease of assembly is improved. For example, the semi-annular magnetic collecting ring disclosed in Patent Document 1 is assembleable in that it can be assembled from the radial direction as compared with the annular magnetic collecting ring in which the torsion bar 13 and the multipolar magnet 14 need to be passed through. Excellent for. In some embodiments, not only is it possible to assemble from the radial direction, but also the magnetic sensor module 50 is miniaturized to improve the manufacturing yield, reduce the space for component management, and further improve the assembleability.

Next, with reference to FIGS. 3A to 22B, a detailed configuration of the magnetic sensor module 50 will be described for each embodiment. Regarding the following first to ninth embodiments, the code of the magnetic sensor module is the number of the embodiment in the third digit following "50", and the code of the set of magnetic flux induction members is "51", " The number of the embodiment is assigned to the third digit following "52". In the tenth to fourteenth embodiments, the reference numerals of the magnetic sensor modules are "1" to "4" in order of the third digit following "55". Further, with respect to the tenth to thirteenth embodiments, the reference numerals of the set of magnetic flux guiding members are sequentially added with "0" to "3" in the third digit following "56" and "57". In the fourteenth embodiment, the reference numeral of the magnetic flux guiding member on only one side is “564”.

As a general rule, the configuration of the magnetic sensor module of each embodiment is shown by three views: a plan view, a side view, and an axial sectional view. However, if any of the figures is substantially the same as the above-described embodiment, the above-mentioned figure is appropriately incorporated. Further, in the specification, for example, "in a plan view" means "when a plan view is viewed". In the first embodiment, FIG. 3A is a plan view, FIG. 3B is a side view, and FIG. 4 is an axial sectional view. Strictly speaking, the "plan view" is a radial cross-sectional view in which the multipolar magnet 14 and the claws 33 and 34 of the yokes 31 and 32 are cut at the upper part of the upper magnetic flux guiding member 51, but from the viewpoint of the magnetic flux guiding member 51. Notated as "plan view". Further, although the ring is actually visible only in the lower yoke 32 in the radial cross-sectional view, the reference numerals are given as "31, 32" including the upper yoke 31 for convenience of explanation.

In each plan view, a "reference line X" extending in the left-right direction through the central axis O is described. In the diagram of the configuration including the two magnetic sensors 71 and 72 as shown in FIG. 3A, the reference line X is defined as a virtual straight line connecting the intermediate position of the two magnetic sensors 71 and 72 and the central axis O. In other words, the two magnetic sensors 71, 72 are arranged symmetrically with respect to the reference line X. In the diagram of the configuration including one magnetic sensor 71 as shown in FIG. 19, the reference line X is defined as a virtual straight line connecting the one magnetic sensor 71 and the central axis O. Further, each plan view is a view in a neutral state in which the torsion bar 13 is not twisted and displaced. In the neutral state, the center line of the magnetic pole (S pole in the example of FIG. 3A) coincides with the reference line X.

The side view is a view of the magnetic sensor module 50 viewed from the outside in the radial direction along the reference line X. The alternate long and short dash line indicates the outer shape of the claws 33 and 34. In the side view, the torsion bar 13 and the multi-pole magnet 14 are not shown. The axial sectional view is a sectional view on a plane including the central axis O and the reference line X. In the axial sectional view, the torsion bar 13 is not shown, and the multi-pole magnet 14 shows only the outline.

(First Embodiment)
The first embodiment will be described with reference to FIGS. 3 (a), 3 (b), and 4. In the magnetic sensor module 501 of the first embodiment, the main body of the magnetic flux guiding members 511 and 521 is formed in a rectangular band shape symmetrical with respect to the reference line X in a plan view. The side of the magnetic flux guiding members 511 and 521 on the O side of the central axis is a straight line orthogonal to the reference line X inside the yokes 31 and 32.

The magnetic flux guiding members 511 and 521 have extending portions 61 and 62 extending radially outward from the main body 60, and the "branch portion of the main body 60 to the extending portions 61 and 62" is referred to as an S portion. The "branch portion to the extension portions 61 and 62" substantially means the vicinity of the magnetic sensors 71 and 72. The "S part" is the same symbol as the S pole of the multi-pole magnet 14, but the distinction between them is obvious and there is no risk of confusion.

Further, the portions corresponding to both ends in the circumferential direction of the yokes 31 and 32 in the range facing the main body 60 of the magnetic flux guiding member 511 and 521 and the yokes 31 and 32 with the reference line X sandwiched are defined as "peripheral end portions 63 and 64 of the main body 60". , And is indicated by dashed hatching in the figure. The peripheral end portions 63 and 64 are portions that "correspond" to "both ends in the circumferential direction in the facing range between the main body 60 and the yokes 31 and 32", and the peripheral end portions 63 and 64 themselves face the yokes 31 and 32. It does not have to be directly included in the range. For example, the peripheral end portions 63 and 64 may correspond to "both ends in the circumferential direction in the direct facing range" on the outside of the directly facing range, that is, on the side away from the reference line X. The distance ds from the S portion to the central axis O is shorter than the distance de from the peripheral end portions 63 and 64 to the central axis O.

In the side view and the axial cross-sectional view, the magnetic flux guiding members 511 and 521 face the annular surfaces of the yokes 31 and 32 with a constant gap inside in the axial direction, and the facing area thereof is close to that of the magnetic sensors 71 and 72. It is relatively large at the intermediate portion 65, and decreases toward the peripheral ends 63 and 64. Since the facing area of the S portion, which is the branching portion to the extending portions 61 and 62, is larger than that of the peripheral end portions 63 and 64, the magnetism per unit area between the magnetic flux guiding members 511 and 521 and the yokes 31 and 32. The permeance increases.

Here, the meaning of "per unit area" is to clearly state that the area of the range in which the magnetic permeance is compared is the same for each part. In the following description of the embodiment, the description of "per unit area" is omitted, and "magnetic permeance" is interpreted as meaning "magnetic permeance per unit area".

The two magnetic sensors 71 and 72 are arranged between the extension portions 61 and 62, respectively. The extension portions 61 and 62 are bent in the axial direction so as to minimize the gap in the portion where the magnetic sensors 71 and 72 are arranged between them, and have a step. The configurations of the extension portions 61 and 62 are common to the following second to seventh and ninth to eleventh embodiments.

Next, with reference to FIGS. 5 (a), 5 (b), and 6, the effects of the magnetic sensor module 50 of each embodiment excluding the tenth embodiment will be described. First, the reason why the signal becomes large will be described. FIG. 5A shows a correlation diagram between the distance or rotation angle from the reference line X and the magnetic permeance for the magnetic permeance between the magnetic flux guiding members 51 and 52 and the yokes 31 and 32. The magnetic permeance P is represented by the formula (1) using the magnetic permeability μ of the material, the facing area A, and the gap length L.
P = μ (A / L) ・ ・ ・ (1)

Here, assuming that the magnetic flux guiding members 51 and 52 are formed of a single soft magnetic material, the larger the facing area A between the magnetic flux guiding members 51 and 52 and the yokes 31 and 32, or the gap length. The shorter L, the larger the magnetic permeance P.

In the first embodiment and the like, the gap between the magnetic flux guiding members 51 and 52 and the yokes 31 and 32 is constant, but the facing area becomes smaller from the intermediate portion 65 toward the peripheral end portions 63 and 64. On the other hand, in the third embodiment described later and the like, the facing area between the magnetic flux guiding members 51 and 52 and the yokes 31 and 32 is constant, but the gap increases from the intermediate portion 65 toward the peripheral end portions 63 and 64. Therefore, in any of the embodiments, the magnetic permeance of the intermediate portion 65 is larger than the magnetic permeance of the peripheral end portions 63 and 64. In FIG. 5A, the correlation characteristic is a straight line like P1, a simple curve without an inflection point like P2, an S-shaped curve like P3, or a stepped polygonal line. There may be.

By the way, Japanese Patent No. 5090162 and US Pat. No. 7,644,635 have a configuration in which "the magnetic permeance between the magnetic flux guiding member and the yoke is determined independently of the relative radius and angular position". It is disclosed. This means that it has a characteristic that the magnetic permeance is constant regardless of the distance from the reference line X. This characteristic is shown by a broken line in FIG. 5A as a comparative example. The characteristics of this embodiment are clearly different from the characteristics of the comparative example in that the magnetic permeance changes according to the distance from the reference line X or the rotation angle.

Then, in each embodiment except the tenth embodiment, the magnetic sensors 71 and 72 are installed in the main body 60 near the intermediate portion 65 or in the extension portions 61 and 62 branched from the main body 60. Here, "installed" includes a form in which the magnetic sensors 71 and 72 are arranged in a non-contact position close to the extension portions 61 and 62, and the magnetic sensors 71 and 72 are not necessarily arranged in the extension portions 61. It does not mean to touch 62. The installation portion of the magnetic sensors 71, 72 or the branch portion to the extension portions 61, 62 in the main body 60 of the magnetic flux induction members 51, 52 substantially means "near the magnetic sensors 71, 72". The magnetic flux guiding members 51 and 52 are the installation portions of the magnetic sensors 71 and 72 in the main body 60 or the branching portions to the extending portions 61 and 62, and are "magnetic flux guiding members 51 and 52" as compared with the peripheral end portions 63 and 64. The magnetic permeance per unit area between the and the yokes 31 and 32 is increased. As a result, the signals of the magnetic sensors 71 and 72 can be increased.

Next, the reason why the runout noise is reduced will be described. In the torque detection device of the prior art such as Patent Document 1, the shape of the magnetic collecting ring is formed in an annular shape, a semicircular shape, a semi-elliptical shape, or the like along the ring of the yoke. With these shapes, the magnetic flux is collected from a wide range of the magnetic collection ring to the magnetic sensor part, so that the signal becomes large to some extent and at the same time, the magnetic flux fluctuations of each part are also collected, resulting in a large swing. Fluctuations occur. On the other hand, in each embodiment except the tenth embodiment, the magnetic permeance between the yokes 31 and 32 and the magnetic flux guiding members 51 and 52 is reduced at the peripheral end portions 63 and 64 away from the magnetic sensors 71 and 72. It is configured in.

In FIG. 3A of the first embodiment, magnetic flux flows between the yokes 31 and 32 and the magnetic flux guiding members 511 and 521, particularly in the S portion having a large magnetic permeance. Then, the magnetic flux that has flowed into the magnetic flux guiding members 511 and 521 flows so as to leak and spread toward the peripheral end portions 63 and 64, as shown by the broken line arrow B. This is because the magnetic flux density is low and the magnetic resistance is low at the peripheral end portions 63 and 64 of the magnetic flux guiding members 511 and 521, unlike the magnetic collecting ring of the torque detection device of the prior art. As a result, the fluctuation of the magnetic flux flowing to the magnetic sensors 71 and 72 side through the extending portions 61 and 62 is suppressed, that is, the effect of smoothing the magnetic flux is produced.

For example, in a neutral state where the magnetic poles of the multipolar magnet 14 are between the claws 33 and 34 of the two yokes 31, 32, that is, no torque is applied, the conventional magnetic collecting ring only collects magnetic flux. , Large swing noise is generated. On the other hand, since the magnetic flux induction members 511 and 521 of the first embodiment have a structure that suppresses fluctuations in the collected magnetic fluxes, fluctuations in swing noise are reduced as shown in FIG. 5 (b). In addition, in the configuration including the two magnetic sensors 71 and 72, the magnetic flux induced from the yokes 31 and 32 branches from the reference line X side toward the two magnetic sensors 71 and 72 and reaches the peripheral ends 63 and 64. It spreads toward you. By this action, it is possible to reduce the propagating run-out noise.

Regarding the signals of the magnetic sensors 71 and 72, the magnetic permeance between the magnetic flux guiding members 511 and 521 and the yokes 31 and 32 in the vicinity of the magnetic sensors 71 and 72 having the highest contribution to the collected magnetic flux amount. Is increased to collect magnetic flux, so the effect on signal degradation is small. From the above, in each embodiment other than the tenth embodiment, it is possible to suppress the swing noise (N) while obtaining a large signal (S) as compared with the conventional technique. Therefore, the SN ratio of the magnetic flux detected by the magnetic sensors 71 and 72 can be improved.

Next, with reference to FIG. 6, the improvement of the manufacturing yield by using the magnetic flux guiding members 511 and 512 of the first embodiment will be described. For example, when the sheet metal material is punched out with a press to take two magnetic flux guiding members 511 and 512, the main bodies 60 are arranged so that the extending portions 61 and 62 face each other, and the layout is made so that the unevenness fits each other. Since the side opposite to the extending portions 61 and 62 is a straight line, the width of the material used to take the two magnetic flux guiding members 511 and 512 is W1.

For comparison, the arc-shaped magnetic flux guiding members 513 and 523 in the third embodiment are shown by alternate long and short dash lines. In this form, it is necessary to use a material having a width W3 in order to take two magnetic flux guiding members 511 and 512, which is wasteful. On the other hand, in the first embodiment, waste of the material can be minimized, and the manufacturing yield is improved. Further, since the magnetic flux guiding members 511 and 521 have a small width in the reference line X direction, they can be assembled to the torque detection device 10 by sliding them as shown by the block arrow IN in the space of the width Win shown in FIG. 3A. .. Therefore, as compared with the case of assembling, for example, a semi-annular magnetic flux induction member, the assembling property can be further improved.

(Second Embodiment)
Regarding the magnetic sensor module 502 of the second embodiment, the side view and the axial sectional view of the magnetic sensor module 502 of the second embodiment refer to FIGS. 3 (b) and 4 of the first embodiment. In the plan view of FIG. 7, the code of the magnetic flux guiding member including the lower magnetic flux guiding member is referred to as “512,522”.

As shown in FIG. 7, in the magnetic sensor module 502 of the second embodiment, in a plan view, the main body of the magnetic flux guiding members 512 and 522 is formed in a band shape having concentric arcs symmetrical with respect to the reference line X as opposite sides. Has been done. This concentric arc is centered on a point Q located on the reference line X on the opposite side of the magnetic sensors 71 and 72 with respect to the central axis O, and has a smaller curvature than the arc centered on the central axis O. Similar to the first embodiment, the distance ds from the S portion, which is a branching portion to the extension portions 61, 62 in the main body 60, to the central axis O is from the distance de from the peripheral end portions 63, 64 to the central axis O. Is also short.

The magnetic flux guiding members 512 and 522 face the yokes 31 and 32 with a constant gap inside in the axial direction. The facing area is relatively large at the intermediate portion 65 close to the magnetic sensors 71 and 72, and decreases toward the peripheral ends 63 and 64. Since the facing area of the branching portion to the extending portions 61 and 62 is larger than that of the peripheral end portions 63 and 64, the magnetic permeance between the magnetic flux guiding members 512 and 522 and the yokes 31 and 32 becomes large. Therefore, the second embodiment has the same effect of improving the SN ratio as the first embodiment. The first embodiment in which the side of the magnetic flux guiding member on the O side of the central axis is a straight line is interpreted as a special mode in which the point Q of the second embodiment exists at infinity and the curvature of the arc is infinitesimal. To.

(Third Embodiment)
For the magnetic sensor module 503 of the third embodiment, FIG. 4 of the first embodiment is used as an axial sectional view. As shown in FIGS. 8A and 8B, in the magnetic sensor module 503 of the third embodiment, the main body of the magnetic flux guiding member 513 has a concentric arc centered on the central axis O in a plan view. It is formed in a strip shape on the opposite side. The magnetic flux guiding members 513 and 523 face the yokes 31 and 32 inside in the axial direction, and the facing area thereof is constant in the circumferential direction of the yokes 31 and 32.

When viewed from the side, the axial gap between the magnetic flux guiding members 513 and 523 and the yokes 31 and 32 ranges from the gap gc at the intermediate portion 65 near the magnetic sensors 71 and 72 to the gap ge at the peripheral ends 63 and 64. , It becomes larger toward the peripheral ends 63 and 64. Since the gap at the branching portion to the extending portions 61 and 62 is smaller than that at the peripheral end portions 63 and 64, the magnetic permeance between the magnetic flux guiding members 513 and 523 and the yokes 31 and 32 becomes large. Therefore, the third embodiment has the same effect of improving the SN ratio as the first embodiment.

(Fourth Embodiment)
As shown in FIGS. 9 (a), 9 (b), and 10, in the magnetic sensor module 504 of the fourth embodiment, the main body of the magnetic flux guiding members 514 and 524 has the outer shapes of the yokes 31 and 32 in a plan view. It is formed in a rectangular band shape that is located on the outer side in the radial direction and is symmetrical with respect to the reference line X. The side of the magnetic flux guiding members 514 and 524 on the central axis O side is a straight line orthogonal to the reference line X. Therefore, the fourth embodiment has the same effect of miniaturization and improvement of yield as the first embodiment.

The magnetic flux guiding members 514 and 524 face the side surfaces of the yokes 31 and 32 in the radial direction in the side view and the axial cross-sectional view. The height of the facing portions in the axial direction is constant. The radial gap between the magnetic flux guiding members 514 and 524 and the yokes 31 and 32 increases from the intermediate portion 65 near the magnetic sensors 71 and 72 toward the peripheral ends 63 and 64. Since the gap at the branching portion to the extending portions 61 and 62 is smaller than that at the peripheral end portions 63 and 64, the magnetic permeance between the magnetic flux guiding members 514 and 524 and the yokes 31 and 32 becomes large. Therefore, the fourth embodiment has the same effect of improving the SN ratio as the first embodiment.

(Fifth and sixth embodiments)
11 and 12 show axial cross-sectional views of the magnetic sensor modules 505 and 506 of the fifth and sixth embodiments. The fifth and sixth embodiments are other variations relating to the facing configuration of the magnetic flux induction member and the yoke. The plan-view shape of the main body of the magnetic flux guiding members 515, 525, 516, 526 of the fifth and sixth embodiments has a rectangular band shape as in the first and fourth embodiments, or an arc as in the second embodiment. It may be in the shape of a strip on the opposite side.

While the magnetic flux guiding members 511, 521 and the like of the first embodiment face the annular surfaces of the yokes 31 and 32 inside in the axial direction, as shown in FIG. 11, the magnetic flux guiding members 515 and 525 of the fifth embodiment Is arranged on the outer side in the axial direction, and faces the annular surfaces of the yokes 31 and 32 on the outer side in the axial direction. Further, as shown in FIG. 12, the magnetic flux guiding members 516 and 526 of the sixth embodiment face the annular surfaces and side surfaces of the yokes 31 and 32 on the outer side in the axial direction and in the radial direction. As described above, the magnetic flux induction member of each embodiment may be arranged so as to face the yokes 31 and 32 in the axial direction, the radial direction, or a combination thereof as appropriate.

(7th Embodiment)
As shown in FIGS. 13 (a), 13 (b), and 14, in the magnetic sensor module 507 of the seventh embodiment, the main bodies of the magnetic flux guiding members 517 and 527 are the yokes 31 and 32 in a plan view. It is located radially outside the outer shape, and is formed in a band shape having a concentric arc centered on the central axis O as the opposite side.

A wall portion 35 for ensuring an axial height is formed on the peripheral edges of the yokes 31 and 32 in a side view and an axial cross-sectional view. Instead of forming the wall portion 35, the thickness of the yokes 31 and 32 may be simply increased. The magnetic flux guiding members 517 and 527 face the side surfaces of the yokes 31 and 32 in the radial direction, and the gap in the radial direction is constant. Further, the axial height of the main body of the magnetic flux guiding members 517 and 527 decreases from the intermediate portion 65 near the magnetic sensors 71 and 72 toward the peripheral end portions 63 and 64. Therefore, the facing area between the magnetic flux guiding members 517 and 527 and the yokes 31 and 32 becomes smaller from the intermediate portion 65 toward the peripheral end portions 63 and 64. At the branching portion (S portion) to the extending portions 61 and 62, the facing area is larger than that of the peripheral end portions 63 and 64, so that the magnetic permeance between the magnetic flux guiding members 517 and 527 and the yokes 31 and 32 becomes large. .. Therefore, the seventh embodiment has the same effect of improving the SN ratio as the first embodiment.

(8th Embodiment)
The axial sectional view of the magnetic sensor module 508 of the eighth embodiment is omitted. As shown in FIGS. 15 (a) and 15 (b), in the magnetic sensor module 506 of the eighth embodiment, the magnetic flux guiding members 518 and 528 are composed of only a rectangular band-shaped main body, and the extending portions 61 and 62 are provided. I don't have it. In the magnetic flux guiding members 518 and 528, the magnetic sensors 71 and 72 are arranged between the sensor holding portions 66 and 67 bent so as to be close to each other in the axial direction. In this embodiment, the installation portion of the magnetic sensors 71 and 72 in the main body 60 substantially corresponds to "near the magnetic sensors 71 and 72". The eighth embodiment has the same effect of improving the SN ratio as the first embodiment, and the magnetic sensor module 506 can be made smaller.

(9th Embodiment)
The side view and the axial sectional view of the magnetic sensor module 509 of the ninth embodiment are omitted. In the plan view of FIG. 16, the code of the magnetic flux guiding member including the lower magnetic flux guiding member is described as “519, 529”. As shown in FIG. 16, in the magnetic sensor module 509 of the ninth embodiment, the magnetic flux guiding members 519 and 529 are formed by being divided into one side and the other side of the reference line X, respectively. In other respects, the ninth embodiment is similar to the first embodiment. In the ninth embodiment, in addition to the effect of the first embodiment, the manufacturing yield of the magnetic flux induction member can be further improved by omitting the intermediate portion 65. In the ninth embodiment, it is premised that two magnetic sensors 71, 72, or four or more even magnetic sensors are arranged symmetrically with respect to the reference line X.

(10th Embodiment)
For the magnetic sensor module 510 of the tenth embodiment, FIG. 4 of the first embodiment is incorporated as an axial sectional view. As shown in FIGS. 17A and 17B, in the magnetic sensor module 550 of the tenth embodiment, the magnetic flux guiding members 560 and 570 extend with respect to the magnetic flux guiding members 511 and 521 of the first embodiment. The difference is that the installation portions 61 and 62 are provided near the peripheral ends 63 and 64. That is, in the tenth embodiment, the facing area between the magnetic flux guiding members 560 and 570 and the yokes 31 and 32 at the S portion, which is the branching portion to the extending portions 61 and 62, is smaller than that at the intermediate portion 65. .. It should be noted that the magnetic sensors 71 and 72 may be directly installed on the main body 60 without providing the extension portion as in the eighth embodiment.

As shown in FIG. 18 corresponding to FIG. 5 (a), in the tenth embodiment, in the correlation diagram between the distance or rotation angle from the reference line X and the magnetic permeance, the magnetic sensors 71 and 72 have the peripheral end 63. , 64 is located near. Therefore, the magnetic flux guiding members 560 and 570 of the tenth embodiment are the S portions of the main body 60 which are branching portions to the extending portions 61 and 62, and are the magnetic flux guiding members 560 and 570 as compared with the portions on the reference line X. It is configured so that the magnetic permeance between the yokes 31 and 32 is small. Further, "the magnetic permeance between the magnetic flux guiding member and the yoke is determined independently of the relative radius and the angular position", that is, in the comparative example in which the magnetic permeance is constant regardless of the distance from the reference line X. The tenth embodiment is common to the first embodiment in that it differs from the characteristics.

From the viewpoint of improving the SN ratio, the tenth embodiment does not have the effect of increasing the signal as in the first embodiment. However, the magnetic flux induced from the yokes 31 and 32 branches from the reference line X side toward the two magnetic sensors 71 and 72, as shown by the broken line arrow M. As a result, it is possible to reduce the propagating run-out noise. Therefore, also in the tenth embodiment, the SN ratio of the magnetic flux detected by the magnetic sensors 71 and 72 is improved. Due to such characteristics, the tenth embodiment is premised on a configuration in which two or more even-numbered magnetic sensors are arranged symmetrically with respect to the reference line X, as in the ninth embodiment.

(11th and 12th embodiments)
In contrast to the first to tenth embodiments including two magnetic sensors 71 and 72, the magnetic sensor module may be configured such that one magnetic sensor is arranged on the reference line X. Here, an embodiment in which the magnetic sensor is changed to one with respect to the first and eighth embodiments will be described as the eleventh and twelfth embodiments.

The side view and the axial sectional view of the magnetic sensor module 551 of the eleventh embodiment are omitted. In the plan view of FIG. 19, the reference numerals of the magnetic flux guiding members including the lower magnetic flux guiding member are referred to as “561, 571”. As shown in FIG. 19, the magnetic flux guiding members 561 and 571 differ from the magnetic flux guiding members 511 and 521 of the first embodiment in that one extending portion 61 corresponding to one magnetic sensor 71 is formed. ..

The side view and the axial sectional view of the magnetic sensor module 552 of the twelfth embodiment are omitted. In the plan view of FIG. 20, the reference numerals of the magnetic flux guiding members including the lower magnetic flux guiding member are referred to as “562, 572”. As shown in FIG. 20, the magnetic flux guiding members 562 and 572 differ from the magnetic flux guiding members 518 and 528 of the eighth embodiment in that one sensor holding portion 66 corresponding to one magnetic sensor 71 is formed. ..

As described above, except for the ninth and tenth embodiments on the premise that the two magnetic sensors 71 and 72 are provided, the number of magnetic sensors applied to the magnetic sensor module of each embodiment is at least two. However, it may be three or more. Specifically, the number of extending portions or sensor holding portions of the magnetic flux guiding member may be adjusted according to the number of applied magnetic sensors.

(13th Embodiment)
In each of the above embodiments, the magnetic sensors 71 and 72 are arranged so that the wide surface of the substantially rectangular parallelepiped IC package is orthogonal to the axis (so-called sideways). On the other hand, the magnetic sensor module 553 of the thirteenth embodiment shown in FIGS. 21 (a) and 21 (b) is arranged so that the wide surface of the IC package of a substantially rectangular parallelepiped is parallel to the axis (so-called vertical orientation). Will be done. In FIG. 21A, the reference numerals and hatching of the peripheral end portions 63 and 64 are omitted.

For example, the main bodies of the magnetic flux guiding members 563 and 573 are located radially outside the outer shape of the yokes 31 and 32 in a plan view and have a rectangular band shape symmetrical with respect to the reference line X, as in the fourth embodiment. It is formed in a radial direction and faces the yokes 31 and 32 in the radial direction. The extension portion 611 that bends downward and extends from the upper magnetic flux guiding member 563 holds the radial outside of the magnetic sensor 71. The extension portion 612 that bends upward and extends from the lower magnetic flux guiding member 573 holds the inside of the magnetic sensor 71 in the radial direction. The thirteenth embodiment is effective, for example, when the lead wire 73 is to be taken out in the axial direction. The thirteenth embodiment can be applied to a configuration in which one magnetic sensor is used.

(14th Embodiment)
In each of the above embodiments, a set of magnetic flux guiding members facing each of the set of yokes is provided. On the other hand, in the magnetic sensor module 554 of the 14th embodiment shown in FIGS. 22 (a) and 22 (b), the magnetic flux guiding member is provided only on one yoke side and not on the other yoke side. .. For example, the magnetic flux induction member 564 is arranged between the set of yokes 31 and 32 in the axial direction, and the upper end thereof faces the upper yoke 31. The magnetic sensor 71 is arranged between the lower end of the magnetic flux guiding member 564 and the lower yoke 32. That is, the magnetic flux is directly transmitted from the lower yoke 32 to the lower surface of the magnetic sensor 71 without passing through the magnetic flux guiding member. As described above, the magnetic flux guiding members do not necessarily have to be provided in a set so as to face each of the sets of yokes. The 14th embodiment can be applied to a configuration in which the magnetic sensor is one.

(Other embodiments)
(A) In FIG. 1 and the like of the above embodiment, the set of yokes 31 and 32 is an annular shape having a constant width, and the claws 33 and 34 are formed so as to bend in the axial direction from the inner circumference of the yokes 31 and 32. There is. On the other hand, in the pair of yokes 36 and 37 shown in FIGS. 23A and 23B, the inside of the ring is cut out at the portion between the adjacent claws 38 and 39, and the width of the ring is narrow. It has become. In other words, the claws 38 and 39 are formed so as to project inward from the ring and then bend in the axial direction. As a result, the area of the magnetic circuit of the claws 38 and 39 can be expanded, and the magnetic flux collected in the yokes 36 and 37 can be increased.

(B) Assuming that the magnetic flux guiding members 51 and 52 of the above embodiment are formed of a single soft magnetic material, the magnetic permeance of each part is changed depending on the area facing the yokes 31 and 32 or the difference in the gap. ing. In addition, according to the equation (1), it is theoretically possible to change the magnetic permeance depending on the part by forming a magnetic flux induction member by laminating two or more kinds of materials having different magnetic permeability μ.

(C) In the above embodiment, the multi-pole magnet 14 is fixed to the input shaft 11 and a set of yokes 31 and 32 are fixed to the output shaft 12, but conversely, a set of multi-pole magnets 14 is fixed to the output shaft 12. The yokes 31 and 32 of the above may be fixed to the input shaft 11. Further, the multi-pole magnet 14 may be fixed to one end side of the torsion bar 13, and a set of yokes 31 and 32 may be fixed to the other end side of the torsion bar 13.

(D) The torque detection device of the present invention is not limited to the electric power steering device, and can be applied to various devices that detect shaft torque.

As described above, the present invention is not limited to such embodiments, and can be implemented in various embodiments without departing from the spirit of the present invention.

10 ... Torque detector,
11 ・ ・ ・ Input axis (1st axis), 12 ・ ・ ・ Output axis (2nd axis),
13 ・ ・ ・ Torsion bar, 14 ・ ・ ・ Multi-pole magnet,
31, 32 ... A set of yokes,
50 (502) ... Magnetic sensor module,
51 (512), 52 (522) ... Magnetic flux induction member,
60 ・ ・ ・ Main body, 61, 62 ・ ・ ・ Extension part, 63, 64 ・ ・ ・ Peripheral end part,
71, 72 ... Magnetic sensor, X ... Reference line.

Claims (7)

A torsion bar (13) that coaxially connects the first axis (11) and the second axis (12) and converts the torque applied between the first axis and the second axis into a torsional displacement.
A multi-pole magnet (14) fixed to one end side of the first axis or the torsion bar and having N poles and S poles alternately arranged in the circumferential direction.
It is formed of a soft magnetic material, is fixed to the second axis or the other end side of the torsion bar on the outer diameter of the multipolar magnet, faces each other in the axial direction, and forms a magnetic circuit in the magnetic field of the multipolar magnet. With a pair of yokes (31, 32)
One or more magnetic flux guiding members (512, 522) formed of a soft magnetic material, in which at least one of the yokes and the main body (60) face each other and induce the magnetic flux of the magnetic circuit.
With one or more magnetic sensors (71, 72) installed in the main body of the magnetic flux guiding member or the extension portions (61, 62) branched from the main body and detecting the magnetic flux induced by the magnetic flux guiding member. ,
With
In the axial projection of the yoke,
When there is one magnetic sensor, the magnetic sensor and the central axis of the yoke are connected, and when there are a plurality of magnetic sensors, a virtual straight line connecting the intermediate positions of the plurality of magnetic sensors and the central axis of the yoke is used as a reference. Line (X)
When the portions corresponding to both ends in the circumferential direction of the yoke in the facing range between the main body of the magnetic flux guiding member and the yoke with the reference line sandwiched are defined as the peripheral ends (63, 64) of the main body of the magnetic flux guiding member.
The magnetic flux guiding member is a portion where the magnetic sensor is installed in the main body or a branching portion to the extending portion, and has a magnetic permeance per unit area between the magnetic flux guiding member and the yoke as compared with the peripheral end portion. It is configured to be large and
The main body of the magnetic flux guiding member is centered on a point that is symmetrical with respect to the reference line and is located on the reference line on the side opposite to the magnetic sensor with respect to the central axis of the yoke, and is the center of the yoke. A torque detection device formed in a strip shape with concentric arcs whose curvature is smaller than the arc centered on the axis as opposite sides. The torque detection device according to claim 1, further comprising the two magnetic sensors arranged symmetrically with respect to the reference line. The torque detecting device according to claim 1 or 2, wherein the magnetic flux guiding member faces the yoke at least in the axial direction of the yoke. The torque detection device according to any one of claims 1 to 3, further comprising a set of the magnetic flux guiding members facing each of the set of yokes. Each of the magnetic flux guiding members has the extending portion extending radially outward from the main body of the yoke.
The torque detection device according to claim 4, wherein the magnetic sensor is arranged between the extension portions of the set of the magnetic flux induction members. The fifth aspect of the present invention, wherein the extending portion of the set of the magnetic flux guiding members has a step in the axial direction of the yoke so that a gap is minimized in a portion where the magnetic sensor is arranged between them. Torque detector. Used in the torque detection device according to any one of claims 1 to 6.
A magnetic sensor module in which the magnetic flux guiding member and the magnetic sensor are integrally configured.

Images