JP6762537B2 - Redundant distortion sensor - Google Patents

Description

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

As a redundant distortion sensor of this type (for example, used for electronically controlled power steering) that has been conventionally used, 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 device shown in FIG. 1 of Patent Document 1 used in a general automobile, and is one side of a 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. Further, the wheel gear 13 is driven by a worm gear 12 of the motor 11 and is configured to be able to steer each of the front wheels 10 via the wheel gear 13.

On the upstream side of the wheel gear 13, a magnetostrictive torque sensor including 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. The steering wheel 2 is connected via the 30 and the steering shaft 1.
Further, 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 via a signal line 40.

When the handle 2 is rotated with 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 rotation speed and angle of the handle, the state of distortion of the magnetostrictive torque sensor, the presence or absence of failure, and the left-right rotation of the handle 2 are performed by mutual communication of information between the magnetostrictive torque sensor 30 and the motor 11. It is configured to be able to detect the limit state of.

Further, FIG. 6 describes a magnetostrictive torque sensor having a conventional configuration different from the conventional configuration shown in FIG.
Reference numerals 60 and 61 in FIG. 6 are first and second stator cores for forming the redundant strain sensor 500, and the stator cores 60 and 61 are separated from each other with respect to an axis (not shown). It 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 axis center P.
Each of the magnetic poles 63 to 65 is composed of a pair of an exciting coil 70 and a detection coil 71, and the first system detection unit 80 is composed of the first and second magnetic poles 63 and 64, and the third and fourth magnetic poles are formed. The second system detection unit 81 is configured by 64. A double redundant system is configured by the system detection units 80 and 81.

Japanese Unexamined Patent Publication No. 2006-64445

Since the redundant distortion 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 to be a minimum of two, but due to problems of detection sensitivity and accuracy, a total of four are required, two for each of the upper and lower parts.

Furthermore, in order to guarantee failures, etc., it is necessary to have double redundancy. For that purpose, eight detection coils, which are doubled, are arranged coaxially, but each of the eight detection coils Since the magnetic flux direction to be generated and the axial direction are the same, the distortion detection accuracy is deteriorated due to the magnetic noise in the direction penetrating the shaft (so-called torsion bar).

The present invention has been made to solve the above problems. In particular, a pair of stator cores provided apart from each other on the shaft are made into a double redundant system, and a plurality of magnetic fluxes formed on each stator 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 the excited magnetic flux is completed in a slot.

The redundant strain sensor according to the present invention includes an anisotropy imparting portion formed on the outer periphery of the shaft, and 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. It consists of a stator core, first, second, third, and fourth magnetic poles that are formed so as to project inside the first and second stator cores and have an exciting coil and a detection coil, respectively, and the first and second magnetic poles. In the redundant system distortion sensor composed of the double redundant system formed on the first and second stator cores by the first system detection unit and the second system detection unit composed of the third and fourth magnetic poles, respectively. It has a configuration having magnetic flux bypass teeth formed integrally with the first stator core or the second stator core by bending both sides in the plane of each magnetic pole and projecting inward, and any of the pair of magnetic flux bypass teeth. 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 when viewed in a plane including a part of the first or second stator core. It is a configuration that has.

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 apart from each other along the axial direction, and the first, The first, second, third, and fourth magnetic poles formed so as to project inside the second stator core and having an exciting coil and a detection coil, respectively, and a first system detection unit composed of the first and second magnetic poles and the said In a redundant system distortion sensor composed of a double redundant system formed on each of the first and second stator cores by a second system detection unit composed of the third and fourth magnetic poles, both sides of the magnetic flux are viewed on both sides. By having a configuration having a magnetic flux bypass tooth formed integrally with the first stator core or the second stator core, which is bent inward and protrudes inward, it is used as an exciting coil and a detection coil, respectively, and changes depending on the inverse magnetostrictive characteristics of the shaft. The torque is calculated from the voltage from the output coil induced by the magnetic flux from the exciting coil.
At this time, by arranging 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, it is possible to arrange the configuration of two systems for redundancy in one core without considering the influence of excitation interference.
Further, the pair of the magnetic flux bypass teeth and one of the magnetic poles are formed integrally with the first or second stator core, and are flat including a part of the first or second stator core. By adopting the configuration formed in the shape of the number 3 as seen, each magnetic pole is covered with a pair of magnetic flux bypass teeth, and the influence of excitation interference at the time of excitation can be prevented.

It is sectional drawing which shows the redundant system 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. FIG. 5 is an output characteristic diagram when the output characteristics of impedance (that is, output voltage) from each detection coil at the time of input torque of the redundant strain sensor according to the present invention are output separately in the CW direction and the CCW direction. It is sectional drawing which shows the electric power steering apparatus using the conventional distortion sensor. It is a top view which shows the conventional redundant system 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 a pair of stator cores provided on the shaft, and the magnetic flux generated by being excited by each magnetic flux bypass tooth is generated in each slot. Since it can be completed, the influence of magnetic fluxes from adjacent slots can be eliminated.

Hereinafter, preferred embodiments of the redundant strain sensor according to the present invention will be described with reference to the drawings.
The same or equivalent parts as those of the conventional example will be described using the same reference numerals.
In FIG. 1, what is indicated by reference numeral 200 is a shaft commonly called a torsion bar, which is often used in the magnetostrictive torque sensor of the above-mentioned electric power steering device.
A pair of first and second magnetostrictive films 201 and 202 having different magnetic anisotropy, for example, plating, grooving, etc., impart anisotropy to the outer periphery of the shaft 200 of this type of magnetostrictive torque sensor. The shaft 200 is formed as a portion 203, and the shaft 200 is integrally formed as the first and second detection shaft portions 204 and 205, although the dotted line is provided.
That is, when the shaft 200 is used, the twist is input so that the CW and CCW are in opposite directions with the dotted line portion as a boundary.

The 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 stator cores 60 are provided on the upper side 200a of the axially central portion of the shaft 200. The magnetic poles 64 and 66 are located 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. There is.

The first and second stator cores 60 and 61 show exactly the same shape, and when the first and second stator cores 60 and 61 are shown as a plan view in a state where they are overlapped, the plan view state of FIG. 2 is obtained. The outer peripheral portions 60a and 61a of the stator cores 60 and 61 are fitted and fixed to the recesses 60b and 61b of the inner wall of the housing 300, respectively.

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 the first and second magnetostrictive films 201 of the shaft 200. It is provided in contact with each of 202.
The first magnetic pole 63 of the first stator core 60 is provided with a first system exciting coil 70, and the first system exciting coil 70 is provided with a first system detection coil 71 adjacent to the first magnetic pole 63.
A first system exciting coil 70 is provided on the second magnetic pole 64 of the first stator core 60, and a first system detection coil 71 is provided inside the first system exciting coil 70.

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

A second system exciting coil 70a is provided on the third magnetic pole 65 of the first stator core 60, and a second system detection coil 71a is provided adjacent to the inside of the second system exciting coil 70a. There is.
A second system exciting coil 70a is provided on the fourth magnetic pole 66 of the first stator core 60, and a second system detection coil 71a is provided adjacent to and inside the second system exciting coil 70a. There is.

The second system detection unit 81 is composed of the third and fourth magnetic poles 65 and 66, and both sides of the third and fourth magnetic poles 65 and 66 project inward integrally with the second stator core 61. 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 in.
Further, each magnetic flux bypass tooth 90 has a figure three shape when viewed as a flat surface 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 in the above and excited can be completed in the slots 91a to 91d and 92a to 92d, and the influence in the adjacent slots 91a to 91d and 92a to 92d can be prevented.

Further, since the second stator core 61 of FIG. 3 has exactly the same shape and configuration as the first stator core 60 described above, the same parts as those of FIG. 2 are designated by the same reference numerals. However, even in the same part as in FIG. 2, only the reference numeral is changed from that in FIG.
That is, the third and fourth system exciting 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 parts as those in FIG. 2, but only the reference numerals are changed. There is.
Since each configuration of FIG. 3 is the same as the configuration of FIG. 2 and only the reference numerals are changed, the description of FIG. 2 is incorporated. That is, the feature of the present invention is to provide the magnetic flux bypass teeth 90 to prevent the influence from adjacent slots.

Further, 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 has an independent first system detection unit 80 and an independent system detection unit 80. The second system detection unit 81 is configured to form a double redundant system.
Further, the second stator core 61 is provided on the lower side 200b of the shaft 200, and the second stator core 61 is configured with an independent first system detection unit 80 and a second system detection unit 81, respectively.
Therefore, when the redundant strain sensor 500 having the configuration shown in FIG. 1 is attached to the electric power steering device shown in FIG. 5, when the upper side 200a is twisted in the counterclockwise direction CCW as shown in FIG. 4, the lower side is twisted. On the contrary, the 200b is twisted in the clockwise direction CW, and the distortion state of the upper 200a and the lower 200b at that time is the distortion of the redundant system of the first and second stator cores 60 and 61 shown in FIGS. 2 and 3. With the sensor, both the upper side 200a and 200b can measure the redundant digital distortion of the dual system as a voltage change by converting it into an impedance, that is, a change in 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, which are formed so as to project inside the first and second stator cores 60 and 61 and have exciting coils 70, 70a, 70A, 70aA and detection coils 71, 71a, 71A, 71aA, respectively. , The first system detection unit 80 including the first and second magnetic poles 63 and 64, and the second system detection unit 81 including the third and fourth magnetic poles 65 and 66. In a redundant system distortion sensor composed of a double redundant system 150 formed on the first and second stator cores 60 and 61, respectively, the first and second stator cores are bent on both sides in a plane of the magnetic fluxes 63 to 66 and protrude inward. 1 The configuration has a magnetic flux bypass teeth 90 integrally formed with the stator core 60 or the second stator core 61, and the pair of the magnetic flux bypass teeth 90 and one of the magnetic poles 63 to 66 are It is formed integrally with the first or second stator cores 60 and 61, and is formed in the shape of a number 3 when viewed in a plane including a part (1A) of the first or second stator cores 60 and 61. It is a composition.

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

1A Part 60 1st stator core 60a Outer circumference 60b, 61b Recessed 61 2nd stator core 61a Outer circumference 63 1st magnetic pole 64 2nd magnetic pole 65 3rd magnetic pole 66 4th magnetic pole 70 1st system exciting coil 70a 2nd system exciting coil 70A 3rd system exciting coil 70aA 4th system exciting 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 unit 81 2nd system detection unit 90 Magnetostriction bypass Teeth 91a 1st slot 91b 2nd slot 91c 3rd slot 91d 4th slot 150 Double redundant system 200 Axis 200a Upper side 200b Lower side 201 1st magnetostrictive film 202 2nd magnetostrictive film 203 Anisotropy imparting part 205 2nd detection Shaft 204 1st detection Shaft 300 Housing 500 Redundant system distortion sensor

Claims (2)

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) apart from each other along the axial direction. And the second stator core (61) and the first and second stator cores (60,61) are formed so as to project inside, and the exciting coil (70,70a, 70A, 70aA) and the detection coil (71,71a, respectively) are formed. The first system detection unit (80) and the first system detection unit (80) composed of the first, second, third, and fourth magnetic poles (63 to 66) having 71A, 71aA) and the first and second magnetic poles (63, 64). From the double redundant system (150) formed on the first and second stator cores (60,61) by the second system detection unit (81) composed of the third and fourth magnetic poles (65,66). In the redundant distortion sensor
It has a magnetic flux bypass tooth (90) formed integrally with the first stator core (60) or the second stator core (61) by bending both sides in a plane of each of the magnetic poles (63 to 66) and projecting inward. A redundant distortion sensor characterized by having a configuration. The pair of magnetic flux bypass teeth (90) and one of the magnetic poles (63 to 66) are integrally formed with the first or second stator core (60,61), and the first The redundant strain sensor according to claim 1, further comprising a configuration in which a part (1A) of the second stator core (60,61) is formed in the shape of a number 3 when viewed in a plane.

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