JP2018115982A - Redundant strain sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve S/N ratio of detection data of each magnetic pole of each stator core.SOLUTION: A redundant strain sensor of the present invention is configured to include pairs of bent or arc-shaped magnetic flux bypass teeth (90), each pair being provided to sandwich respective one of eight magnetic poles (63-66) constituting a redundant system provided on a pair of stator cores (60, 61) provided on a shaft (200) in order to eliminate influence of magnetic flux from adjacent slots (91a-91d).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a redundant system strain sensor, and in particular, a pair of stator cores provided apart from each other on a shaft is a double redundant system, and magnetic flux bypass teeth are provided on both sides of a plurality of magnetic poles formed on each stator. And a new improvement for completing the excited magnetic flux in the slot.

As a conventional redundant strain sensor of this type (for example, used for electronically controlled power steering), for example, the configuration of Patent Document 1 can be listed in FIG.
That is, FIG. 5 is a perspective view showing an outline of the electric power steering apparatus shown in FIG. 1 of Patent Document 1 used for a general automobile, and one side of the rack shaft 8 having a pair of front wheels 10. The pinion 7 of the wheel gear 13 is meshed with the rack portion 8a formed in the above. The wheel gear 13 is driven by the worm gear 12 of the motor 11 so that the front wheels 10 can be steered via the wheel gear 13.

On the upstream side of the wheel gear 13, a magnetostrictive torque sensor comprising a first magnetostrictive film 31, a second magnetostrictive film 32, first and second detection coils 33 and 34, and third and fourth detection coils 35 and 36. A handle 2 is connected via 30 and a steering shaft 1.
A control unit (generally referred to as an ECU) for performing various controls of the electric power steering 100 is connected to the magnetostrictive torque sensor 30 through a signal line 40.

When the handle 2 is rotated in the configuration of FIG. 5 described above, each front wheel 10 can be steered via the magnetostrictive torque sensor 30, the motor 11, the wheel gear 13, the pinion 7 and the rack shaft 8.
Further, in the control unit 50, the number of rotations and angles of the handle, the state of the distortion of the magnetostrictive torque sensor, the presence or absence of a failure, and the right and left rotation of the handle 2 through mutual communication of information with the magnetostrictive torque sensor 30 and the motor 11. It is configured to be able to detect the limit state.

FIG. 6 describes a magnetostrictive torque sensor having a conventional configuration different from the conventional configuration shown in FIG.
In FIG. 6, reference numerals 60 and 61 denote first and second stator cores for constituting the redundant strain sensor 500, and the stator cores 60 and 61 are separated from each other with respect to a shaft (not shown). Is provided.
That is, the first and second stator cores 60, 61 are formed with four magnetic poles 63, 64, 65, 66 protruding from the inner surfaces 60a, 61a toward the axial center P.
Each of the magnetic poles 63 to 65 is composed of a set of an excitation coil 70 and a detection coil 71, and the first and second magnetic poles 63 and 64 constitute a first system detector 80, and the third and fourth magnetic poles 64 constitutes a second system detection unit 81. Each of the system detection units 80 and 81 constitutes a double redundant system.

JP 2006-64445 A

Since the redundant strain sensor provided in the conventional electric power steering is configured as described above, the following problems exist.
That is, in general, one is used for each of the upper and lower anisotropic parts, and the number is two at the minimum. However, a total of four are required, two for each of the upper and lower parts because of problems in detection sensitivity and accuracy.

  Furthermore, it is necessary to provide double redundancy in order to guarantee a failure or the like. To that end, double eight detection coils are arranged on the same axis, but each of the eight detection coils Since the direction of the magnetic flux to be generated and the axial direction are the same, distortion detection accuracy is deteriorated by magnetic noise in a direction penetrating the shaft (so-called torsion bar).

  The present invention has been made to solve the above-described problems, and in particular, a pair of stator cores provided apart from each other on a shaft is a double redundant system, and a plurality of magnetic poles formed on each stator are provided. It is an object of the present invention to provide a redundant strain sensor in which magnetic flux bypass teeth are provided on both sides so that an excited magnetic flux is completed in a slot.

  A redundant strain sensor according to the present invention includes an anisotropy imparting portion formed on an outer periphery of a shaft, a first stator core and a second stator core provided on the outer periphery of the anisotropy imparting portion so as to be separated from each other along the axial direction. The stator core is formed to protrude inside the first and second stator cores, and includes first, second, third, and fourth magnetic poles each having an excitation coil and a detection coil, and the first and second magnetic poles. In a redundant strain sensor comprising a double redundant system formed on each of the first and second stator cores by a first system detecting unit and a second system detecting unit including the third and fourth magnetic poles, Each magnetic pole has a magnetic flux bypass tooth that is bent in both sides as viewed in the plane and protrudes inward, and is integrally formed with the first stator core or the second stator core. The One of the magnetic poles is formed integrally with the first or second stator core, and is formed in the shape of a number 3 in a plan view including a part of the first or second stator core. It is.

Since the redundant strain sensor according to the present invention is configured as described above, the following effects can be obtained.
That is, the anisotropy imparting portion formed on the outer periphery of the shaft, the first stator core and the second stator core provided on the outer periphery of the anisotropy imparting portion along the axial direction, and the first, A first system detector comprising first, second, third, and fourth magnetic poles, each of which has an excitation coil and a detection coil, and is formed to protrude inside the second stator core, and the first system detection unit that includes the first and second magnetic poles, and In a redundant strain sensor composed of a double redundant system formed on each of the first and second stator cores by a second system detector composed of third and fourth magnetic poles, both sides as viewed in the plane of each magnetic pole. And a magnetic flux bypass tooth integrally formed with the first stator core or the second stator core, which are bent inwardly to form an exciting coil and a detecting coil, and change depending on the inverse magnetostrictive characteristics of the shaft. That calculates a torque than the voltage from the induced output coil by the magnetic flux from the excitation coil.
At this time, by disposing the magnetic flux bypass teeth on both sides of the wound teeth, the excited magnetic flux can be completed in the slot, and the influence from the adjacent slots can be eliminated. As a result, two redundant configurations can be arranged in one core without considering the influence of excitation interference.
Further, the pair of magnetic flux bypass teeth and one of the magnetic poles are formed integrally with the first or second stator core, and are a plane including a part of the first or second stator core. By adopting a configuration in which the number 3 is formed, each magnetic pole is covered with a pair of magnetic flux bypass teeth, and the influence of excitation interference during excitation can be prevented.

It is sectional drawing which shows the redundant type | system | group distortion sensor by this invention. It is a top view of the 1st stator core of FIG. It is a top view of the 2nd stator core of FIG. It is an output characteristic figure at the time of outputting separately the output characteristic of the impedance (namely, output voltage) from each detection coil at the time of input torque of the redundant system distortion sensor by the present invention in the CW direction and the CCW direction. It is a cross-sectional block diagram which shows the electric power steering apparatus using the conventional distortion sensor. It is a top view which shows the conventional redundant type | system | group distortion sensor.

  In the redundant strain sensor according to the present invention, magnetic flux bypass teeth are provided on both sides of each magnetic pole formed on the pair of stator cores provided on the shaft, and the magnetic flux excited and generated by each magnetic flux bypass tooth is generated in each slot. Since it can be completed, the influence of the magnetic flux from the slots adjacent to each other can be eliminated.

Hereinafter, preferred embodiments of a redundant strain sensor according to the present invention will be described with reference to the drawings.
The same reference numerals are used for the same or equivalent parts as in the conventional example.
In FIG. 1, what is denoted by reference numeral 200 is a shaft commonly referred to as a torsion bar, and is often used in the magnetostrictive torque sensor of the electric power steering device described above.
On the outer periphery of the shaft 200 of this type of magnetostrictive torque sensor, a pair of first and second magnetostrictive films 201 and 202 having different magnetic anisotropy, for example, plating, groove processing, etc. are imparted with anisotropy. The shaft 200 is formed as a portion 203, and the shaft 200 is provided with a dotted line, but is integrally formed as first and second detection shaft portions 204 and 205.
That is, when the shaft 200 is used, the torsion is input so as to be in the reverse direction of CW and CCW with respect to the dotted line portion.

A first stator core 60 shown in FIG. 2 is provided on the outer periphery of the first magnetostrictive film 201, and the second and fourth of the first stator core 60 are disposed on the upper side 200 a of the central portion in the axial direction of the shaft 200. The magnetic poles 64 and 66 are positioned when viewed in cross section.
The second magnetostrictive film 202 is formed on the lower side 200b of the central portion of the shaft 200 in the axial direction, and the second stator core 61 shown in FIG. 2 is provided on the outer periphery of the second magnetostrictive film 202. Yes.

  The first and second stator cores 60 and 61 have exactly the same shape. When the first and second stator cores 60 and 61 are overlapped and shown as a plan view, the plan view of FIG. The outer peripheral portions 60 a and 61 a of the stator cores 60 and 61 are respectively fitted and fixed to the recesses 60 b and 61 b on the inner wall of the housing 300.

As shown in FIG. 1, the four first, second, third and fourth magnetic poles 63, 64, 65 and 66 of the stator cores 60 and 61 are connected to the first and second magnetostrictive films 201 and 201 of the shaft 200, respectively. 202 are provided in contact with each other.
A first system excitation coil 70 is provided on the first magnetic pole 63 of the first stator core 60, and a first system detection coil 71 is provided adjacent to the first system excitation coil 70.
The second magnetic pole 64 of the first stator core 60 is provided with a first system excitation coil 70, and a first system detection coil 71 is provided inside the first system excitation coil 70.

  The first and second magnetic poles 63 and 64 constitute a first system detection unit 80. The first and second magnetic poles 63 and 64 are protruded inward integrally with the first stator core 60 on both sides of the first and second magnetic poles 63 and 64. A curved or arcuate magnetic flux bypass tooth 90 is formed. As a result, the magnetic flux generated by excitation is completed in each of the slots 91a to 91b, and does not affect the adjacent magnetic poles 63 to 66 (so-called crosstalk prevention). .

The third magnetic pole 65 of the first stator core 60 is provided with a second system excitation coil 70a, and a second system detection coil 71a is provided adjacent to the inside of the second system excitation coil 70a. Yes.
The fourth magnetic pole 66 of the first stator core 60 is provided with a second system excitation coil 70a, and the second system excitation coil 70a is provided with a second system detection coil 71a adjacent to the inside. Yes.

The third and fourth magnetic poles 65 and 66 constitute a second system detecting unit 81, and projecting inward integrally with the second stator core 61 on both sides of the third and fourth magnetic poles 65 and 66. By forming the curved or arc-shaped magnetic flux bypass teeth 90, the magnetic flux generated by excitation is completed in each of the slots 91a to 91d, and the influence of the adjacent slots 91a to 91d can be eliminated. It is configured.
Each of the magnetic flux bypass teeth 90 has a three-digit shape when viewed as a plane using the magnetic poles 63, 64, 65, 66 and a part 1A of the first and second stator cores 60 or 61. The magnetic flux formed and excited can be completed in the slots 91a to 91d and 92a to 92d, and the influence on the adjacent slots 91a to 91d and 92a to 92d can be prevented.

Further, since the second stator core 61 of FIG. 3 is configured in exactly the same manner as the shape and configuration of the first stator core 60 with respect to the first stator core 60 described above, the same parts as those in FIG. However, even in the same part as in FIG. 2, only the reference numerals are changed from those in FIG.
That is, the third and fourth system excitation coils 70A and 70aA, the third and fourth system detection coils 71A and 71aA, and the first to fourth slots 91a to 94a are the same as in FIG. Yes.
3 is the same as the configuration of FIG. 2 and only the reference numerals are changed, and the description of FIG. That is, the characteristic feature of the present invention is to provide a magnetic flux bypass tooth 90 to prevent the influence from adjacent slots.

The redundant strain sensor according to the present invention will be further described.
The first stator core 60 is provided on the upper side 200a of the shaft 200, the second stator core 61 is provided on the lower side 200b of the shaft 200, and the first stator core 60 includes an independent first system detector 80 and The second system detection unit 81 is configured to configure a double redundant system.
The second stator core 61 is provided on the lower side 200b of the shaft 200. The second stator core 61 includes a first system detection unit 80 and a second system detection unit 81 that are independent of each other.
Accordingly, when the redundant strain sensor 500 having the configuration of FIG. 1 is mounted on the electric power steering apparatus of FIG. 5, when the upper side 200a is twisted in the counterclockwise direction CCW, as shown in FIG. 200b is subjected to a clockwise CW twist, and the distortion state of the upper side 200a and the lower side 200b at that time is the distortion of the redundant system of the first and second stator cores 60 and 61 shown in FIGS. With the sensor, both of the upper side 200a and 200b can measure a double redundant digital distortion as a voltage change in terms of a change in impedance, that is, a voltage.

Next, the gist of the redundant strain sensor according to the present invention is as follows.
That is, the anisotropy imparting portion 203 formed on the outer periphery of the shaft 200, and the first stator core 60 and the second stator core 61 provided on the outer periphery of the anisotropy imparting portion 203 apart from each other along the axial direction. The first, second, and third stator cores 60, 61 project from the first and second stator cores 61, 61 and have excitation coils 70, 70a, 70A, 70aA and detection coils 71, 71a, 71A, 71aA, respectively. The fourth magnetic poles 63 to 66, the first system detection unit 80 composed of the first and second magnetic poles 63 and 64, and the second system detection unit 81 composed of the third and fourth magnetic poles 65 and 66, In the redundant strain sensor comprising the double redundant system 150 formed on each of the first and second stator cores 60 and 61, the first and second stator cores 60 and 61 are bent inward on both sides as viewed in the plane of the magnetic poles 63 to 66 and protrude inward. 1 s The magnetic flux bypass teeth 90 formed integrally with the data core 60 or the second stator core 61, and the pair of magnetic flux bypass teeth 90 and one of the magnetic poles 63 to 66 are A structure that is formed integrally with the first or second stator core 60, 61 and that is formed in the shape of the number 3 in a plan view including a part (1A) of the first or second stator core 60, 61. It is.

  In the redundant strain sensor according to the present invention, a pair of stator cores are provided in a two-stage shape on the shaft anisotropy imparting portion, and a pair of bent or arc-shaped magnetic flux bypass teeth are provided on both sides of the magnetic pole of each stator core. The influence from adjacent slots can be eliminated, and a redundant dual system configuration can be obtained in one core.

1A Part 60 First stator core 60a Outer peripheral portion 60b, 61b Recess 61 Second stator core 61a Outer peripheral portion 63 First magnetic pole 64 Second magnetic pole 65 Third magnetic pole 66 Fourth magnetic pole 70 First system excitation coil 70a Second system excitation coil 70A 3rd system excitation coil 70aA 4th system excitation coil 71 2nd system detection coil 71a 2nd system detection coil 71A 3rd system detection coil 71aA 4th system detection coil 80 1st system detection part 81 2nd system detection part 90 Magnetic flux bypass Teeth 91a first slot 91b second slot 91c third slot 91d fourth slot 150 double redundant system 200 shaft 200a upper side 200b lower side 201 first magnetostrictive film 202 second magnetostrictive film 203 anisotropy imparting part 205 second detection Shaft portion 204 First detection shaft portion 300 Housing 500 Redundant strain center

Claims (2)

An anisotropy imparting portion (203) formed on the outer periphery of the shaft (200), and a first stator core (60) provided on the outer periphery of the anisotropy imparting portion (203) spaced apart from each other along the axial direction And the second stator core (61) and the first and second stator cores (60, 61) projecting from the inside, respectively, the excitation coil (70, 70a, 70A, 70aA) and the detection coil (71, 71a, 71A, 71aA) having the first, second, third and fourth magnetic poles (63 to 66), the first and second magnetic poles (63, 64), the first system detector (80) and the first 3. A double redundant system (150) formed on each of the first and second stator cores (60, 61) by a second system detector (81) comprising a fourth magnetic pole (65, 66). In the redundant strain sensor
The magnetic flux bypass teeth (90) are formed integrally with the first stator core (60) or the second stator core (61) by bending inward on both sides as viewed in the plane of each magnetic pole (63-66) and projecting inward. A redundant strain sensor characterized by having a configuration.   The pair of magnetic flux bypass teeth (90) and one of the magnetic poles (63 to 66) are formed integrally with the first or second stator core (60, 61), and the first The redundant strain sensor according to claim 1, wherein the second stator core (60, 61) includes a part (1A) and is formed into a number 3 figure in a plan view.

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