JP2005156163A - Rotational angle detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact rotational angle detector that has high detection precision and is used, for example, for detecting the rotational angle of the steering of an automobile. <P>SOLUTION: A detection body 12 that is rotated in linking with the rotation of a rotor 11 is arranged in a direction in which a rotary axis orthogonally crosses that of the rotor 11, thus increasing the number of teeth in the rotor 11 for increasing the detection precision of a rotational angle, and obtaining the rotational angle detector having high detection precision without increasing external shape even if the outer diameter of the rotor 11 is increased. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rotation angle detection device mainly used for detecting a rotation angle of a steering wheel of an automobile.

  2. Description of the Related Art In recent years, with the advancement of functions of automobiles, a rotation angle detection device that detects the rotation angle of a steering wheel is required to have high detection accuracy in order to perform vehicle body travel control and the like.

  Such a conventional rotation angle detection device will be described with reference to FIGS.

  FIG. 7 is a cross-sectional view of a conventional rotation angle detecting device, and FIG. 8 is a perspective view of the main part. In FIG. 7, reference numeral 1 denotes a rotating body having a spur gear portion 1A formed on the outer periphery, and is inserted through the central portion. An engaging portion that engages with a shaft of a steering (not shown) is provided.

  Reference numeral 2 denotes a detection body having a magnet 3 mounted at the center thereof. The detection body 2 is arranged side by side with the rotating body 1, and a spur gear portion 2A formed on the outer periphery meshes with the spur gear portion 1A of the rotating body 1. ing.

  Reference numeral 4 denotes a first wiring board disposed in parallel with the detection body 2, and a plurality of wiring patterns (not shown) are formed on both surfaces, and the first wiring board 4 is connected to the detection body 2. A magnetism detecting element 5 is mounted on the facing surface, and a detecting means 6 is constituted by the magnet 3 and the magnetism detecting element 5 facing each other.

  Reference numeral 7 denotes a second wiring board connected to the first wiring board 4 by lead wires 8, and a control means 9 comprising a microcomputer or the like for processing a detection signal from the magnetic detection element 5 is formed. A rotation angle detection device is configured by being connected to an electronic circuit (not shown) of the automobile body through a connector (not shown) or the like.

  In the above configuration, when the steering is rotated, the rotating body 1 is rotated accordingly, and the detection body 2 in which the spur gear portion 2A is engaged with the spur gear portion 1A on the outer periphery is also rotated.

  As the detection body 2 rotates, the magnetic field of the magnet 3 mounted at the center of the detection body 2 changes, and the magnetism detection element 5 detects this changing magnetism and gradually increases or decreases in periodicity. A detection signal having a substantially triangular voltage waveform is output to the control means 9.

  At this time, for example, the number of teeth of the spur gear portion 1A of the rotating body 1 is set to be three times the number of teeth of the spur gear portion 2A of the detecting body 2, and the magnet is generated every time the detecting body 2 and the magnet 3 rotate 180 degrees. If the detection element 5 detects one voltage waveform, the detection body 2 rotates three times while the rotation body 1 makes one rotation, and the magnetic detection element 5 changes by two for one rotation of the detection body. In order to detect the waveform, six voltage waveforms are continuously output as detection signals.

  That is, each time the rotating body 1 rotates 60 degrees, one voltage waveform of a substantially triangular shape that gradually increases and decreases is output from the magnetic detection element 5 to the control means 9 as a detection signal.

  Then, the calculation unit of the control means 9 first calculates the number of periods of the waveform of the detection signal from the magnetic detection element 5 to detect the approximate rotation angle of the rotating body 1 every 60 degrees, and then the voltage The exact rotation angle of the rotating body 1 is detected by the value.

  Further, since this voltage waveform is a waveform that gradually increases and decreases every 60 degrees of rotation of the rotating body 1, for example, if arithmetic processing is performed using a 10-bit analog / digital converter in the microcomputer of the control means 9, 0 and 1 Rotation angle can be detected with a resolution of 60 degrees / 1024≈0.06 degrees.

  As described above, the control unit 9 is configured to detect the rotation angle of the rotating body 1 based on the number of waveforms and the voltage value of the detection signal from the magnetic detection element 5.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2002-206910 A

  However, in the conventional rotation angle detection device, in order to further increase the detection accuracy of the rotation angle, the number of teeth of the spur gear portion 1A of the rotating body 1 is increased so that the rotation of the rotating body 1 is performed once. This can be realized by rotating the detection body 2 three times or more, for example, four rotations, and reducing the detection angle per one waveform of the voltage waveform, but by increasing the number of teeth of the rotation body 1, the outer diameter of the rotation body 1 can be realized. Therefore, there is a problem that the outer shape of the rotation angle detection device becomes large.

  The present invention solves such a conventional problem, and an object of the present invention is to provide a rotation angle detection device that has a simple configuration and is small in size and high in rotation angle detection accuracy.

  In order to achieve the above object, the present invention has the following configuration.

  According to the first aspect of the present invention, the rotation angle detection device is configured by arranging the detection body that rotates in conjunction with the rotation of the rotating body in a direction in which the rotation axis is orthogonal to the rotation axis of the rotating body. Since the detection body is arranged in a state orthogonal to the lower periphery of the outer periphery of the rotating body, even if the number of teeth of the rotating body is increased to increase the detection accuracy of the rotation angle, and the outer diameter of the rotating body is increased, Compared with the case where the rotating body and the detection body are arranged side by side, the rotation angle detecting device having a small outer shape can be obtained.

  According to a second aspect of the invention, in the first aspect of the invention, bevel gear portions are respectively formed on the outer periphery of the rotating body and the outer periphery of the detecting body, and these are meshed with each other, and the detecting body is the rotating body. Therefore, it is possible to perform detection with a small outer shape and a small rotation angle error.

  The invention according to claim 3 is the invention according to claim 1, wherein the detection means is formed by a magnet and a magnetic detection element, and the detection means and the control means are formed on the same wiring board. Since the detection means and the control means are provided on one wiring board, the number of components is small, and it is possible to obtain a rotation angle detection device that is easy and inexpensive to assemble.

  As described above, according to the present invention, it is possible to obtain an advantageous effect that it is possible to obtain a rotation angle detection device that is small in size and high in rotation angle detection accuracy with a simple configuration.

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

(Embodiment)
FIG. 1 is a sectional view of a rotation angle detecting device according to an embodiment of the present invention, FIG. 2 is a perspective view of the main part, FIG. 3 is an exploded perspective view of the same, and 11 is a bevel gear part 11A on the outer periphery. An engaging portion 11B that engages with a shaft of a steering (not shown) to be inserted is provided at the center portion.

  Reference numeral 12 denotes a detection body having a bevel gear portion 12A formed on the outer periphery, and a magnet 13 is attached to the center of the detection body 12 by insert molding or the like.

  Further, the bevel gear portion 12A of the detection body 12 meshes with the bevel gear portion 11A of the rotating body 11 at right angles, and the detection body 12 is supported by the shaft support portion 14A of the cover 14 and the substantially annular support member 15. It is held rotatably in conjunction with the rotation of.

  That is, the rotating body 11 and the detecting body 12 are arranged such that the rotation axis that is the rotation center line of the detecting body 12 is in a direction perpendicular to the axis of the rotating body 11.

  The number of teeth of the bevel gear portion 11A of the rotating body 11 is, for example, four times the number of teeth of the bevel gear portion 12A of the detection body 12, and the number of teeth is three times as described in the background art section. The number of teeth is larger than that of the number, and therefore the outer diameter of the rotating body 11 is large.

  Further, reference numeral 16 denotes a wiring board disposed on the center side of the rotating body 11 so as to face the detecting body 12 in parallel. A plurality of wiring patterns (not shown) are formed on both surfaces, and the detecting body of the wiring board 16 is also provided. A magnetic detection element 17 such as an AMR element (anisotropic magnetic detection element) is mounted on a surface facing the magnetic field 12, and a detection means 18 is configured by the magnet 13 and the magnetic detection element 17 facing each other.

  Similarly, the wiring board 16 is formed with a control means 19 composed of a microcomputer or the like for processing a detection signal from the magnetic detection element 17, and the control means 19 is connected to the electronic circuit (not shown) of the automobile body through the connector 20 or the like. It is connected to the.

  Reference numeral 21 denotes a case made of an insulating resin, and reference numeral 22 denotes a cover made of an insulating resin. These and the cover 14 cover the rotating body 11, the detection body 12, the wiring board 16, etc., and are positioned and rotated at predetermined positions. An angle detection device is configured.

  In the above configuration, when the steering is rotated, the rotating body 11 is rotated accordingly, and the detecting body 12 in which the bevel gear portion 12A meshes with the outer bevel gear portion 11A is also rotated.

  As the detection body 12 rotates, the magnetic field generated by the magnet 13 attached to the center of the detection body 12 changes. The magnetic detection element 17 detects this changing magnetic field, and is shown in the voltage waveform diagram of FIG. Such a detection signal in which a substantially triangular voltage waveform continues with a periodicity that gradually increases or decreases is output from the magnetic detection element 17 of the detection means 18 to the control means 19.

  At this time, as described above, for example, the number of teeth of the bevel gear portion 11A of the rotating body 11 is set to four times the number of teeth of the bevel gear portion 12A of the detection body 12, and the magnetic detection element 17 is set only for the strength of magnetism. If detection is performed, that is, one voltage waveform is detected each time the detection body 12 rotates 180 degrees, the detection body 12 rotates four times while the rotation body 11 rotates once, and the magnetic detection element 17 Detects two waveforms for one rotation of the detection body 12, so that eight voltage waveforms are continuously output as detection signals.

  That is, every time the rotating body 11 rotates 45 degrees, one voltage waveform of a substantially triangular shape that gradually increases and decreases is output from the magnetic detection element 17 to the control means 19 as a detection signal.

  Then, the calculation unit of the control means 19 first calculates the number of periods of the waveform of the detection signal from the magnetic detection element 17, detects the approximate rotation angle of every 45 degrees of the rotating body 11, and then An accurate rotation angle of the rotating body 11 is detected based on the voltage value.

  For example, as shown in the voltage waveform diagram of FIG. 5, in the case of the rotation angle θ, first, the number of waveforms of the detection signal is the second counted from the reference 0 degree, and therefore, first between 45 degrees and 90 degrees. The approximate rotation angle is detected, and then it is detected by the voltage value v that the rotation body 11 is at an accurate rotation angle, for example, 60 degrees.

  Further, since this voltage waveform is a waveform that gradually increases and decreases every 45 degrees of rotation of the rotating body 11, for example, if arithmetic processing is performed using a 10-bit analog / digital converter in the microcomputer of the control means 19, 0 and 1 The rotation angle can be detected with a high resolution of 45 degrees / 1024≈0.045 degrees.

  That is, although the number of teeth of the rotating body 11 is increased and the outer diameter of the rotating body 11 is increased and the detection accuracy of the rotating angle is increased as compared with the conventional rotation angle detecting device described in the background art section. Since the detection body 12 is arranged orthogonally to the rotating body 11, the outer shape of the apparatus in the outer diameter direction of the rotating body 11 can be made smaller than that of the conventional one.

  As described above, the control unit 19 is configured to detect the rotation angle of the rotating body 11 based on the number of waveforms of the detection signal from the magnetic detection element 17 and the voltage value.

  As described above, according to the present embodiment, the detection body 12 is arranged orthogonally below the rotation body 11 by arranging the detection body 12 in a direction in which the rotation axis is orthogonal to the rotation axis of the rotation body 11. Therefore, even if the number of teeth on the outer periphery of the rotating body 11 is increased, a rotation angle detection device with high detection accuracy can be obtained without increasing the outer shape of the device.

  In addition, the bevel gear portion 11A is formed on the outer periphery of the rotating body 11, and the bevel gear portion 12A is also formed on the outer periphery of the detecting body 12, and these are meshed with each other, so that the detecting body 12 is securely attached to the rotating body 11. Since they rotate in conjunction with each other, it is possible to perform detection with a small outer shape and a small rotation angle error.

  Further, the detection means 18 is formed by the magnet 13 and the magnetic detection element 17, and the detection means 18 and the control means 19 are formed on the same wiring board 16, whereby the detection means 18 and the control are controlled on one wiring board 16. Since the means 19 is provided, it is possible to obtain a rotation angle detecting device that has a small number of components and is easy and inexpensive to assemble.

  In the above description, the configuration in which one detecting body 12 is engaged with the rotating body 11 and the control means 19 detects the rotation angle of the rotating body 11 based on the detection signal from the detecting means 18 has been described. As shown in the perspective view of the main part, a plurality of detection bodies 32, 33, and 34 that rotate in conjunction with the rotation of the rotation body 31 are provided, and detection means and the like are provided so as to face them. The present invention can also be implemented with a configuration in which the detection accuracy is further increased by the detection signal from the detection body 33 having a different number of teeth.

  Alternatively, the rotation abnormality of the detection body 32 may be detected by a detection signal from the detection body 34 having the same number of teeth as the detection body 32 and directly meshing with the rotation body 31.

  Further, the present invention can be implemented even if the rotation angle detection device is configured only by the detection bodies 32 and 34 that are directly meshed with the rotation body 31 or is configured by only the detection body 32 and the detection body 34 that meshes with the detection body 32. It is.

  The rotation angle detection device according to the present invention has an advantageous effect that it is possible to obtain a detection device with a simple configuration and a small size and high detection accuracy of the rotation angle, and is useful for detecting the rotation angle of the steering of an automobile. .

Sectional drawing of the rotation angle detection apparatus by one embodiment of this invention Perspective view of the main part Exploded perspective view Same voltage waveform diagram Same voltage waveform diagram Perspective view of main part according to another embodiment Sectional view of a conventional rotation angle detector Perspective view of the main part

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 31 Rotating body 11A, 12A Bevel gear part 12, 32, 33, 34 Detection body 13 Magnet 14, 22 Cover 14A Shaft support 15 Support member 16 Wiring board 17 Magnetic detection element 18 Detection means 19 Control means 20 Connector 21 Case

Claims (3)

A rotating body that rotates in conjunction with the steering, a detecting body that rotates in conjunction with the rotation of the rotating body, a detection means that detects the rotation of the detecting body as a detection signal, and the rotation of the rotating body from the detection signal A rotation angle detection device comprising control means for detecting an angle, wherein the detection body is arranged in a direction in which a rotation axis is orthogonal to a rotation axis of the rotation body. The rotation angle detection device according to claim 1, wherein bevel gear portions are respectively formed on an outer periphery of the rotating body and an outer periphery of the detection body, and are engaged with each other. The rotation angle detecting device according to claim 1, wherein the detecting means is formed by a magnet and a magnetic detecting element, and the detecting means and the control means are formed on the same wiring board.

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