JP4622641B2 - Rotation angle detector - Google Patents

Description

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

  2. Description of the Related Art In recent years, as automobiles have become more sophisticated, in order to perform various controls such as braking and skidding prevention, the number of devices that detect the rotation angle of a steering using various rotation angle detection devices is increasing.

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

  FIG. 4 is a perspective view of a main part of a conventional rotation angle detecting device. In FIG. 4, reference numeral 1 denotes a rotating gear having a spur gear 1A formed on its outer periphery, and a shaft of a steering (not shown) inserted through the center portion. An engaging portion 1B that engages with is provided.

  2 is a first detection gear having a spur gear 2A formed on the outer periphery, 3 is a second detection gear having a spur gear 3A having a different number of teeth from the first detection gear 2 on the outer periphery, One detection gear 2 meshes with the rotation gear 1, and the second detection gear 3 meshes with the first detection gear 2, and a magnet 4 is placed at the center between the first detection gear 2 and the second detection gear 3. And 5 are mounted by insert molding or the like.

  Reference numeral 6 denotes a wiring board disposed substantially parallel to the upper surfaces of the first detection gear 2 and the second detection gear 3, and a plurality of wiring patterns (not shown) are formed on both sides, and the first A magnetic detection element 7 is mounted on the surface of the detection gear 2 facing the magnet 4, and a magnetic detection element 8 is mounted on the surface of the second detection gear 3 facing the magnet 5. The first detection means 9 and the second detection means 10 are formed by the elements.

  Furthermore, the control means 11 connected to the 1st detection means 9 and the 2nd detection means 10 is formed in the wiring board 6 by electronic components, such as a microcomputer, and the rotation angle detection apparatus is comprised.

  In such a rotation angle detecting device, the control means 11 is connected to an electronic circuit (not shown) of the automobile body through a connector (not shown) or the like, and at the engaging portion 1B in the center of the rotating gear 1 The steering shaft is inserted and attached to the automobile.

  In the above configuration, when the steering wheel is rotated, the rotating gear 1 is rotated accordingly, and the first detection gear 2 meshed with the outer peripheral spur gear and the second detection gear meshed with the first detection gear 2. The gear 3 rotates in conjunction with it.

  Then, as the first detection gear 2 and the second detection gear 3 rotate, the magnetic directions of the magnets 4 and 5 mounted in the center thereof change, and this is detected by the magnetic detection elements 7 and 8 respectively. A detection signal in which a substantially sawtooth voltage waveform that is detected and repeated to increase and decrease is output from the first detection means 9 and the second detection means 10 to the control means 11.

  At this time, since the number of teeth of the first detection gear 2 and the second detection gear 3 are different, the detection signal output from the first detection means 9 and the second detection means 10 are output. The detected signal is different in voltage waveform shape and has a phase difference.

  Then, the control means 11 calculates the number of teeth of each gear and the voltage values of two detection signals having different voltage waveforms to detect the rotation angle of the rotating gear 1, that is, the steering rotation angle, which is an electronic circuit. And various controls such as a brake of an automobile are performed.

  Between the meshed teeth of the rotary gear 1 and the first detection gear 2 and between the first detection gear 2 and the second detection gear 3, a slight gap for meshing the teeth, A so-called backlash is formed.

  Therefore, for example, as shown in the partial plan view of FIG. 3, the right side of the tooth of the spur gear 1A of the rotary gear 1 and the left side of the tooth of the spur gear 2A of the first detection gear 2 are in contact with each other. When the backlash α is formed on the right side of the tooth of the gear 2, when the rotating gear 1 is rotated counterclockwise, the first detection gear 2 also rotates following this, but clockwise. In the case of rotation, the first detection gear 2 rotates while being shifted by the angle of the backlash α.

  In other words, although the angle is as small as about 1 degree, the rotation angle detected from the first detection gear 2 is the backlash α amount corresponding to the gap between the teeth with respect to the actual rotation angle of the steering wheel. The error was caused.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2005-3625 A

  However, in the conventional rotation angle detection device, an error of about 1 degree is generated as the rotation angle corresponding to the gap between the teeth of each meshed gear and the backlash α, so that it is difficult to detect the rotation angle with high accuracy. There was a problem.

  The present invention solves such a conventional problem, and an object of the present invention is to provide a rotation angle detection device that can detect a rotation angle with high accuracy and less error.

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

According to the first aspect of the present invention, the control means stores the backlash of the rotating gear, the first detection gear, the first detection gear, and the second detection gear, and the first and second detection means. This is to detect the rotation angle of the rotating gear by correcting the error of the backlash with respect to the detection signal from, and detecting the rotation angle by correcting the error between the meshed gears and the backlash. it allows an effect that it is possible to obtain a highly accurate rotation angle detection of possible rotation angle of the detection device.

  The invention according to claim 2 is the invention according to claim 1, wherein the detection means is formed of a magnet and a magnetic detection element or a Hall element, and can perform stable non-contact detection, The rotation angle detection device can be made inexpensive with a simple configuration.

  As described above, according to the present invention, it is possible to obtain an advantageous effect that it is possible to realize a rotation angle detection device that can detect a rotation angle with high accuracy and less error.

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

(Embodiment)
FIG. 1 is a perspective view of a main part of a rotation angle detecting device according to an embodiment of the present invention, FIG. 2 is a block circuit diagram thereof, and in FIG. 1, 1 is a rotating gear having a spur gear 1A formed on its outer periphery. An engaging portion 1B that engages with a shaft of a steering (not shown) to be inserted is provided in the central portion.

  2 is a first detection gear having a spur gear 2A formed on the outer periphery, 3 is a second detection gear having a spur gear 3A having a different number of teeth from the first detection gear 2 on the outer periphery, A spur gear of one detection gear 2 meshes with the rotary gear 1 and a second detection gear 3 meshes with the first detection gear 2, respectively, and at the center of the first detection gear 2 and the second detection gear 3. The magnets 4 and 5 are mounted by insert molding or the like.

  Reference numeral 6 denotes a wiring board disposed substantially parallel to the upper surfaces of the first detection gear 2 and the second detection gear 3, and a plurality of wiring patterns (not shown) are formed on both surfaces, and the first A magnetic detection element 7 such as an AMR element (anisotropic magnetoresistive element) is provided on the surface of the detection gear 2 facing the magnet 4, and a magnetic detection element 8 is also provided on the surface of the second detection gear 3 facing the magnet 5. The first detection means 9 and the second detection means 10 are formed by these opposed magnets and magnetic detection elements.

  Furthermore, the control means 21 connected to the 1st detection means 9 and the 2nd detection means 10 is formed in the wiring board 6 by electronic components, such as a microcomputer, and the rotation angle detection apparatus is comprised.

  In addition, the control means 21 of the rotation angle detection device is formed of a control unit 21A, a storage unit 21B, and a calculation unit 21C. The storage unit 21B includes a rotation gear 1, a first detection gear 2, and a first detection gear. The gap and backlash between each of the meshed gears of the detection gear 2 and the second detection gear 3 are stored.

  That is, there is a slight amount for meshing the teeth between the teeth of the rotating gear 1 and the first detection gear 2 and between the meshed teeth of the first detection gear 2 and the second detection gear 3. A gap, so-called backlash, is formed.

  Therefore, for example, as shown in the partial plan view of FIG. 3, the right side of the tooth of the spur gear 1A of the rotary gear 1 and the left side of the tooth of the spur gear 2A of the first detection gear 2 are in contact with each other. When the backlash α is formed on the right side of the tooth of the gear 2, when the rotating gear 1 is rotated counterclockwise, the first detection gear 2 also rotates following this, but clockwise. In the case of rotation, the first detection gear 2 rotates while being shifted by the angle of the backlash α.

  Therefore, when the rotation angle detection device is manufactured, the rotation gear 1 is rotated, the actual rotation angle of the rotation gear 1 is measured, and the first detection means 9 and the second detection means 10 are detected. When the values calculated from the signals are compared, an error corresponding to the clearance between the gear teeth and the backlash α of about 1 degree is obtained.

  Then, the backlash α for each device is stored in the storage unit 21B shown in FIG. 2, and when the detection signals from the first detection unit 9 and the second detection unit 10 are calculated by the calculation unit 21C, The control unit 21 is configured so that the control unit 21A detects the rotation angle of the rotating gear 1 by correcting the error corresponding to the backlash α.

  Further, in the rotation angle detecting device configured as described above, the control means 21 is connected to an electronic circuit (not shown) of the automobile body through a connector (not shown) and the center of the rotating gear 1 shown in FIG. A steering shaft is inserted into the engaging portion 1B and is attached to the automobile.

  In the above configuration, when the steering wheel is rotated, the rotating gear 1 is rotated accordingly, and the first detection gear 2 meshed with the outer peripheral spur gear and the second detection gear meshed with the first detection gear 2. The gear 3 rotates in conjunction with it.

  Then, as the first detection gear 2 and the second detection gear 3 rotate, the magnetic directions of the magnets 4 and 5 mounted in the center thereof change, and this is detected by the magnetic detection elements 7 and 8 respectively. A detection signal having a substantially sawtooth voltage waveform that is detected and repeated to increase and decrease is output from the first detection means 9 and the second detection means 10 to the control means 21.

  At this time, since the number of teeth of the first detection gear 2 and the second detection gear 3 are different, the detection signal output from the first detection means 9 and the second detection means 10 are output. The detected signal is different in voltage waveform shape and has a phase difference.

  The control means 21 calculates the rotation angle of the rotary gear 1 from the number of teeth of each gear and the voltage values of two detection signals having different voltage waveforms, that is, detects the rotation angle of the steering wheel. In addition, in the storage unit 21B of the control unit 21, when the rotation angle detection device is manufactured, the clearance between the gears engaged with each other and the backlash α are stored.

  Thus, when the control unit 21A of the control unit 21 calculates the detection signals from the first detection unit 9 and the second detection unit 10 by the calculation unit 21C, the backlash α amount stored in the storage unit 21B is calculated. The rotation angle of the rotary gear 1 is detected by correcting the above error.

  That is, the control means 21 detects a high-accuracy rotation angle that matches the actual angle of the rotating gear 1 without an error corresponding to the gap between the gears and the backlash α, and outputs this to the electronic circuit. Various controls such as braking are performed.

  As described above, according to the present embodiment, the control means 21 stores the clearance between the teeth of the rotating gear 1 and each detection gear, the backlash α, and the backlash α corresponding to the detection signal from each detection means. By correcting the error and detecting the rotation angle of the rotating gear 1, a rotation angle detection device capable of detecting the rotation angle with high accuracy can be obtained.

  In addition, by configuring the first detection means 9 and the second detection means 10 with the magnets 4 and 5 and the magnetic detection elements 7 and 8 or the Hall element, non-contact stable detection can be performed. The rotation angle detection device can be made inexpensive with a simple configuration.

  In the above description, spur gears are formed on the outer circumferences of the rotating gear 1, the first detection gear 2, and the second detection gear 3, and these are engaged with each other. The present invention can also be implemented as a configuration using other shapes such as a bevel gear.

  Further, the configuration in which the first detection gear 2 is engaged with the rotary gear 1 and the second detection gear 3 is engaged with the first detection gear 2 has been described. However, the first detection gear 2 and the second detection gear 2 have been described. It is also possible to implement a configuration in which both of them are meshed with the rotating gear 1 or a configuration in which only one detection gear is meshed with the rotating gear 1.

  The rotation angle detection device according to the present invention can realize a device that can detect a rotation angle with a small amount of error and is highly accurate, and is useful for detecting the rotation angle of an automobile steering wheel.

The principal part perspective view of the rotation angle detection apparatus by one embodiment of this invention Same block circuit diagram Partial plan view of rotating gear and detection gear Main part perspective view of a conventional rotation angle detection device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotation gear 1A, 2A, 3A Spur gear 1B Engagement part 2 First detection gear 3 Second detection gear 4, 5 Magnet 6 Wiring board 7, 8 Magnetic detection element 9 First detection means 10 Second detection Means 21 Control means 21A Control part 21B Storage part 21C Calculation part

Claims (2)

The rotating gear that rotates in conjunction with the steering, the first detecting gear that rotates in conjunction with the rotating gear, and the first detecting gear that rotates in conjunction with the first detecting gear have the number of teeth. Different second detection gears, first and second detection means for detecting rotations of the first and second detection gears as detection signals, and control means connected to the first and second detection means The control means stores the backlash of the rotating gear, the first detection gear, the first detection gear, and the second detection gear, and the detection from the first and second detection means. A rotation angle detection device that detects the rotation angle of the rotating gear by correcting the error of the backlash with respect to the signal. The rotation angle detection device according to claim 1, wherein the detection means is formed of a magnet and a magnetic detection element or a Hall element.

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