JP2010151581A - Rotational torque detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotational torque detection device capable of precisely and reliably detecting rotational torque, in the rotational torque detection device mainly used in the detection of the rotational torque of a steering of a vehicle or the like. <P>SOLUTION: The rotational torque detection device 22 is obtained, in which the rotational torque is precisely and reliably detected because external magnetism is prevented to reduce detection errors of a magnetic detection element 19 by providing a magnetic part 11A or 14A on at least one of a lower end of an outer circumference of a first rotor 11 covering the magnetic detection element 19 and an upper end of an outer circumference of a second rotor 14, and integration with another device using a magnet such as a rotational angle detection part 22A is easily achieved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotational torque detecting device mainly used for detecting rotational torque of a steering wheel of an automobile.

  In recent years, with the advancement of advanced functions of automobiles, various rotational torque detectors and rotational angle detectors are used to detect the rotational torque and rotational angle of the steering and perform various controls of the vehicle such as a power steering device and a brake device. Things are increasing.

  Such a conventional rotational torque detection device will be described with reference to FIGS.

  FIG. 7 is a side view of a conventional rotational torque detection device, and FIG. 8 is an exploded perspective view thereof. In FIG. 7, 1 is a substantially cylindrical first rotating body that rotates in conjunction with steering, and 2 is a substantially cylindrical shape. A magnet 2 in which an N pole and an S pole are alternately formed at an angular interval of, for example, about 20 to 40 degrees is fixed to the lower end of the outer periphery of the first rotating body 1.

  Reference numeral 3 denotes a substantially cylindrical second rotating body, 4 denotes a first magnetic body having a plurality of protrusions 4A formed on the inner periphery, and 5 denotes a plurality of protrusions at a location different from the first magnetic body 4. In the second magnetic body in which the portion 5A is formed, the second rotating body 3 is disposed below the first rotating body 1, and the first magnetic body 4 and the second magnetic body 5 are the spacers 6. The second rotating body 3 is fixed to the upper end of the second rotating body 3 so as to face the magnet 2.

  Reference numeral 7 denotes a wiring board disposed substantially parallel to the sides of the first rotating body 1 and the second rotating body 3, and a plurality of wiring patterns (not shown) are formed on the left and right surfaces, and a magnet. 2 is mounted with a magnetic detection element 8 such as a Hall element disposed between the first magnetic body 4 and the second magnetic body 5.

  Further, a control means 9 connected to the magnetic detection element 8 is formed on the wiring board 7 by electronic parts such as a microcomputer, and an upper end is provided between the first rotating body 1 and the second rotating body 3. The first rotating body 1 is provided with a substantially cylindrical connecting body 10 such as a torsion bar whose lower end is fixed to the second rotating body 3 to constitute a rotational torque detecting device.

  Such a rotational torque detection device is mounted on the first rotary body 1 and the second rotary body 3 together with the rotation angle detection device and the like, and is mounted below the steering wheel of the automobile and controlled. The means 9 is connected to an electronic circuit (not shown) of the automobile body through a connector, a lead wire (not shown) or the like.

  In the above configuration, when the steering wheel is rotated, the first rotating body 1 rotates along with this, and after the connecting body 10 is twisted, the second rotating body 3 is slightly delayed from the first rotating body 1. At this time, for example, the rotational torque is small when the vehicle is traveling, so that the delay in the rotation of the second rotating body 3 with respect to the first rotating body 1 is small, and the rotational torque is large when the vehicle is stopped. The delay in rotation of the body 3 is increased.

  And with rotation of this 1st rotary body 1 and the 2nd rotary body 3, the magnet 2 fixed to these, and the 1st magnetic body 4 and the 2nd magnetic body 5 are somewhat behind this, too. The magnetic detection element 8 detects the change in magnetism between the N pole and the S pole of the magnet 2 that rotates and is alternately formed at a predetermined interval, via the first magnetic body 4 and the second magnetic body 5, Input to the control means 9.

  At this time, the magnetism detected by the magnetism detecting element 8 is the second magnet in which the first magnetic body 4 and the second magnetic body 5 are fixed to the first rotating body 1 to which the magnet 2 is fixed. When the rotation delay of the rotating body 3 is small, the magnetism is weak, and when the rotation delay is large, the magnetism is strong.

  Then, the control means 9 calculates the rotational torque of the steering from the strength of the magnetism of the magnetic detection element 8 detected via the first magnetic body 4 and the second magnetic body 5, and this is the electronic torque of the automobile body. Output to the circuit, and the electronic circuit calculates various data from the rotational torque, the rotational angle of the steering wheel, the speed sensor mounted on each part of the vehicle body, etc. Control is performed.

  In other words, for example, when the vehicle is running and the steering torque is small, the power steering device is loosened so that the steering wheel is rotated with a heavy force, and the vehicle stops and the steering wheel rotates. When the torque is large, the power steering device is used greatly, and the steering wheel can be rotated even with a light force.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2007-256140 A

  However, in the conventional rotational torque detection device, when a magnet is used in the rotation angle detection device arranged in the vicinity, or when a device that generates magnetism is arranged nearby, the influence of these magnetisms. Therefore, there is a case where an error occurs in the magnetism of the magnet 2 detected by the magnetic detection element 8, and there is a problem that it is necessary to perform arithmetic processing such as correction in the control means 9 in order to prevent this.

  The present invention solves such a conventional problem, and an object of the present invention is to provide a rotational torque detector that can detect rotational torque with high accuracy and reliability.

  In order to achieve the above object, the present invention provides a rotational torque detection device by providing a magnetic part on at least one of the outer periphery of the lower end of the first rotating body or the outer periphery of the upper end of the second rotating body that covers the magnetic detection element. The magnetic part at the outer periphery of the lower end of the first rotating body or the outer periphery of the upper end of the second rotating body can prevent magnetism from the outside and reduce the detection error of the magnetic detecting element. In addition to being able to detect the rotational torque, it is possible to obtain a rotational torque detecting device that can be easily integrated with other devices using magnets such as a rotational angle detecting device.

  As described above, according to the present invention, it is possible to obtain an advantageous effect that it is possible to realize a rotational torque detector that can detect rotational torque with high accuracy and reliability.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment)
FIG. 1 is a cross-sectional view of a rotational torque detector according to an embodiment of the present invention, FIG. 2 is an exploded perspective view thereof, in which 11 is a substantially cylindrical shape, such as polybutylene terephthalate that rotates in conjunction with steering The first rotating body 12 made of an insulating resin, 12 is a substantially cylindrical holder such as copper or aluminum, and 13 is a substantially cylindrical or substantially ring-shaped magnet such as ferrite or Nd-Fe-B alloy. A magnet 13 in which poles and S poles are alternately formed at a predetermined angular interval of, for example, 30 degrees or 15 degrees is fixed to the lower end of the outer periphery of the holding body 12, and the upper periphery of the holding body 12 is the first on the outer periphery. Fixed to the upper part of the inner periphery of the rotating body 11.

  14 is a substantially cylindrical second rotating body made of an insulating resin such as polybutylene terephthalate, 15 is a substantially ring-shaped first magnetic body such as permalloy, iron, Ni-Fe alloy, and 16 is a second rotating body. The second rotating body 14 is disposed below the first rotating body 11, and a plurality of protrusions 15 </ b> A are provided on the inner periphery of the first magnetic body 15. A plurality of protrusions 16A, for example, six or twelve are formed on the inner periphery of the magnet 13 at positions different from the protrusions 15A, respectively, and these are opposed to the outer periphery of the magnet 13 with a predetermined gap.

  Reference numeral 17 denotes a substantially ring-shaped spacer made of copper, aluminum, or insulating resin. The first magnetic body 15 and the second magnetic body 16 are opposed to the magnet 13 via the spacer 17 and are rotated in the second direction. Each is fixed to the upper end of the body 14.

  Further, 18 is a wiring board such as paper phenol or glass epoxy, and a plurality of wiring patterns (not shown) are formed on the left and right sides, and the side of the first rotating body 11 and the second rotating body 14. Are arranged between the first magnetic body 15 and the second magnetic body 16 on the surface facing the magnet 13, and a Hall element for detecting magnetism in the vertical direction and a horizontal direction A magnetic detecting element 19 such as a GMR element for detecting the magnetism is mounted and mounted.

  A control means 20 connected to the magnetic detection element 19 is formed on the wiring board 18 by an electronic component such as a microcomputer, and an upper end is provided between the first rotating body 11 and the second rotating body 14. The first rotating body 11 and the connecting body 21 made of steel or the like having a substantially cylindrical shape such as a torsion bar each having a lower end fixed to the second rotating body 14 are provided.

  Furthermore, the outer periphery of the lower end of the first rotating body 11 covering the magnetic detection element 19 and the outer periphery of the upper end of the second rotating body 14 are made of permalloy, iron, Ni, etc., covering the outer peripheral side surface in a substantially ring shape by insert molding or the like. A rotational torque detector 22 is configured by integrally forming magnetic portions 11A and 14A such as an Fe alloy.

  Reference numeral 23 denotes a substantially ring-shaped insulating resin or metal rotating gear having a spur gear portion formed on the outer peripheral lower surface, 24 a first detection gear having a spur gear portion formed on the outer peripheral side surface, and 25 a second same. The rotation gear 23 is fixed to the lower end of the outer periphery of the first rotating body 11, the first detection gear 24 is connected to the rotation gear 23, and the second detection gear 25 is connected to the first detection gear 24. Each meshes.

  Note that the diameter and the number of teeth of these gears are the largest in the rotating gear 23, decreasing in the order of the first detecting gear 24 and the second detecting gear 25. For example, the number of teeth of the rotating gear 23 is 48, The number of teeth of the first detection gear 24 is 32, and the number of teeth of the second detection gear 25 is 28.

  A magnet 26A is attached to the center of the first detection gear 24, and a magnet 26B is attached to the center of the second detection gear 25 by insert molding or the like, and arranged substantially parallel to the sides thereof. Magnetic detection elements 27A and 27B such as AMR (anisotropic magnetoresistive) elements are mounted on the facing surfaces of the wiring board 18 facing the magnets 26A and 26B, respectively.

  Furthermore, the control means 28 connected to the magnetic detection elements 27A and 27B is formed on the wiring board 18 by electronic parts such as a microcomputer, and the rotation angle detection unit 22A is configured.

  In other words, in the present embodiment, a rotation angle detection unit 22A that detects the rotation angle of the steering is integrally formed below the rotation torque detection device 22 that detects the rotation torque of the steering.

  The rotational torque detection device 20 configured as described above is mounted on the first rotating body 11 and the second rotating body 14 with a steering shaft and mounted below the steering wheel of the automobile, and the control means 20. And 28 are connected to an electronic circuit (not shown) of the automobile body through a connector, a lead wire (not shown) or the like.

  In the above configuration, when the steering wheel is rotated, the first rotating body 11 is rotated with the rotation of the steering wheel, and the rotating gear 23 fixed to the lower end is rotated. Therefore, the first detecting gear meshed with the rotating gear 23 is rotated. 24 and the second detection gear 25 meshed with the first detection gear 24 rotate in conjunction with each other.

  Then, as the first detection gear 24 and the second detection gear 25 rotate, the direction of magnetism of the magnets 26A and 26B mounted at the center thereof changes, and this is detected by the magnetic detection elements 27A and 27B. Then, a sine wave, cosine wave, or substantially sawtooth detection signal that repeatedly increases and decreases is input to the control means 28.

  At this time, since the number of teeth of the first detection gear 24 and the second detection gear 25 is different, the rotation angle signal output from the magnetic detection element 27A and the rotation angle output from the magnetic detection element 27B. The signal is input to the control means 28 with a data waveform having a different shape and a phase difference.

  Then, the control means 28 determines the rotation angle of the rotation gear 23 from the two rotation angle signals having different waveforms and the number of teeth of each spur gear portion of the first detection gear 24 and the second detection gear 25 with respect to the rotation gear 23. Is calculated, that is, the rotation angle of the steering shaft is detected and output to the electronic circuit of the automobile body.

  At this time, after the connecting body 21 is twisted with the rotation of the steering shaft and the first rotating body 11, the second rotating body 14 rotates slightly behind the first rotating body 11. When the vehicle is running, for example, the rotational torque is small, so the delay in the rotation of the second rotating body 14 with respect to the first rotating body 11 is small, and when the vehicle is stopped, the rotational torque is large. The delay increases.

  Then, as the first rotating body 11 and the second rotating body 14 rotate, the magnets 13 fixed to them, and the first magnetic body 15 and the second magnetic body 16 are slightly delayed. The magnetic detection element 19 detects the change in magnetism between the N pole and the S pole of the magnet 13 that rotates and is alternately formed at a predetermined interval, via the first magnetic body 15 and the second magnetic body 16, Input to the control means 20.

  That is, when the steering wheel is not rotated and is in a neutral position and the vehicle is in a straight traveling state, a plurality of protrusions on the inner periphery of the first magnetic body 15 as shown in the partial side view of FIG. The center of the plurality of protrusions 16A on the inner periphery of the second magnetic body 16 formed at a location different from 15A and the center of the N pole and the S pole formed alternately at predetermined angular intervals of the magnet 13 Therefore, the magnetic force is balanced, and no magnetic flux is generated between the first magnetic body 15 and the second magnetic body 16, and the magnetic detection element 19 disposed between them. The detected magnetism is zero.

  On the other hand, when the steering wheel is rotated with a small rotational torque and the first magnetic body 15 and the second magnetic body 16 rotate with a slight delay with respect to the magnet 13, as shown in FIG. In addition, since the protrusion 15A has an N pole and the protrusion 16A has an S pole, a magnetic flux in the direction from the first magnetic body 15 to the second magnetic body 16 is generated. Will detect.

  When the rotational torque is large, the first magnetic body 15 and the second magnetic body 16 rotate with a large delay with respect to the magnet 13, so that the first magnetic body 15 is rotated as shown in FIG. The magnetism in the direction from the body 15 to the second magnetic body 16 becomes strong, and the magnetism detecting element 19 detects this strong magnetism.

  The control means 20 calculates the rotational torque of the steering shaft from the strength of the magnetism of the magnetic detection element 19 detected through the first magnetic body 15 and the second magnetic body 16, and this is calculated as The power steering device outputs to the electronic circuit, and the electronic circuit calculates the rotational torque, the rotation angle of the steering shaft from the control means 28 described above, or various data from a speed sensor mounted on each part of the vehicle body. Various controls of the vehicle such as the brake device and the brake device are performed.

  That is, for example, the control of the power steering device that adjusts the operating force of the steering wheel according to the running or stopped state of the vehicle by the rotational torque from the control means 20, or the rotation angle from the control means 28, The brake device is controlled in accordance with the rotation.

  At this time, as described above, the magnetic portions 11A and 14A are formed on the outer periphery of the lower end of the first rotating body 11 and the outer periphery of the upper end of the second rotating body 14 covering the magnetic detection element 19, respectively. Therefore, magnetism from the magnets 26A and 26B of the rotation angle detector 22A provided integrally or magnetism from a device that generates magnetism arranged nearby is shielded by the magnetic parts 11A and 14A, and magnetic detection is performed. The element 19 can detect the strength of magnetism without error.

  That is, since the magnetic portions 11A and 14A provided at the outer periphery of the lower end of the first rotating body 11 and the upper end of the second rotating body 14 can prevent magnetism from the outside and reduce the detection error of the magnetic detecting element 19, the control means Even without performing arithmetic processing such as correction at 20, high-precision and reliable rotation torque can be detected, and integration with the rotation angle detector 22A using the magnets 26A and 26B can be easily achieved. It is configured to be able to.

  In the above description, the configuration in which the rotation angle detection unit 22A is integrally formed below the rotation torque detection device 22 has been described. However, as shown in FIGS. 4 and 5, the rotation angle detection unit 22A is formed laterally. It is good also as a structure which formed.

  That is, FIG. 4 is a cross-sectional view of a rotational torque detector according to another embodiment of the present invention, and FIG. 5 is a perspective view thereof. In FIG. The first detection gear 24 is fixed to the lower end of the outer periphery of the first rotating body 11, and the first detection gear 24 is engaged with the rotation gear 23A, and the second detection gear 25 is engaged with the first detection gear 24, respectively.

  Magnetic detection elements 27A and 27B facing the magnets 26A and 26B are mounted on the lower surface of the wiring board 18 arranged substantially in parallel above the first detection gear 24 and the second detection gear 25. These are connected to the control means 28, and the rotation angle detection part 22B is comprised.

  Note that a magnetic detection element 19 facing the magnet 13 is disposed between the first magnetic body 15 and the second magnetic body 16, or the first rotating body 11 and the second rotating body 14. Between these, the connection body 21 is provided in the same manner as described above.

  Furthermore, the outer periphery of the lower end of the first rotating body 11 covering the magnetic detection element 19 and the outer periphery of the upper end of the second rotating body 14 are substantially L-shaped by insert molding or the like and cover the upper surface in addition to the outer peripheral side surface. The parts 11B and 14B are integrally formed.

  That is, the rotation angle detection unit 22B is formed on the side of the rotation torque detection device 22, and the magnetic detection element 19 is covered with the substantially L-shaped magnetic units 11B and 14B, thereby further preventing external magnetism. The detection error of the magnetic detection element 19 can be reduced.

  As described above, the rotation angle detectors 22A and 22B are integrally formed below or on the side of the rotation torque detection device 22, so that the magnetic detection element 19, the magnetic detection elements 27A and 27B, the control means 20, 28 can be formed all on one wiring board 18, so that it is not necessary to use a plurality of wiring boards or connect them with lead wires or the like. It can be formed.

  In the above description, the magnetic parts 11A, 14A, 11B, and 14B have been described as being formed integrally with the first rotating body 11 and the second rotating body 14 by insert molding or the like. The magnetic portions 11A and 14A or the substantially L-shaped magnetic portions 11B and 14B may be formed separately and fitted to the first rotating body 11 and the second rotating body 14.

  In the above description, the configuration in which the magnetic portions 11A, 14A, 11B, and 14B are formed on both the first rotating body 11 and the second rotating body 14 has been described. However, the magnetic shield is somewhat insufficient. However, the present invention can be implemented even if only one of the first rotating body 11 and the second rotating body 14 is provided with a magnetic part.

  Furthermore, in the above description, the plurality of protrusions 15A on the inner periphery of the first magnetic body 15 and the plurality of protrusions 16A on the inner periphery of the second magnetic body 16 are separated from each other with a predetermined gap on the outer periphery of the magnet 13. Although the structure which made it oppose was demonstrated, as shown in the partial side view of FIG. 6, while using the magnet 13A by which the upper end and the lower end were alternately formed in the N pole and the S pole at predetermined angle intervals, this magnet 13A It is good also as a structure which has arrange | positioned several protrusion part 15A and 16A above and below.

  As described above, according to the present embodiment, at least one of the lower end outer periphery of the first rotating body 11 covering the magnetic detection element 19 and the upper end outer periphery of the second rotating body 14 is provided with the magnetic portions 11A, 14A, 11B, By providing 14B, the magnetism from the outside can be prevented and the detection error of the magnetic detection element 19 can be reduced, so that the rotational torque can be detected with high accuracy and reliably, and magnets such as the rotation angle detectors 22A and 22B are used. It is possible to obtain the rotational torque detection device 22 that can be easily integrated with other devices.

  In the above description, the rotation angle detectors 22A and 22B are formed by meshing the first detection gear 24 with the rotation gears 23 and 23A and the second detection gear 25 with the first detection gear 24, respectively. Although the configuration has been described, either the configuration in which both the first detection gear 24 and the second detection gear 25 are meshed with the rotation gears 23 and 23A, or only one of them is meshed with the rotation gears 23 and 23A. The present invention can also be implemented with a different configuration.

  The rotational torque detecting device according to the present invention can realize a device that can detect rotational torque with high accuracy and reliability, and is useful mainly for detecting rotational torque of a steering wheel of an automobile.

Sectional drawing of the rotational torque detection apparatus by one embodiment of this invention Exploded perspective view Side view of the same part Sectional drawing of the rotational torque detection apparatus by other embodiment Same perspective view Side view of the same part Side view of a conventional rotational torque detector Exploded perspective view

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 1st rotary body 11A, 11B, 14A, 14B Magnetic part 12 Holding body 13, 13A Magnet 14 2nd rotary body 15 1st magnetic body 15A, 16A Protrusion part 16 2nd magnetic body 17 Spacer 18 Wiring board DESCRIPTION OF SYMBOLS 19 Magnetic detection element 20 Control means 21 Connection body 22 Rotation torque detection apparatus 22A, 22B Rotation angle detection part 23, 23A Rotating gear 24 First detection gear 25 Second detection gear 26A, 26B Magnet 27A, 27B Magnetic detection element 28 Control means

Claims (1)

A first rotating body that rotates in conjunction with the steering, a magnet fixed to the first rotating body, a second rotating body disposed below the first rotating body, and the second rotating body. First and second magnetic bodies fixed to the rotating body facing the magnet, a magnetic detecting element disposed between the first and second magnetic bodies, and an upper end of the first rotating body The body is composed of a coupling body having a lower end fixed to the second rotating body, and at least one of a lower end outer periphery of the first rotating body covering the magnetic detection element, or an upper end outer periphery of the second rotating body, A rotational torque detector provided with a magnetic part.

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