JP2007261508A - Steering angle detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering angle detector capable of accurately detecting a rotating angle of a rotating shaft in the whole range of a steering angle and accurately detecting the steering angle of a vehicle with a simplified configuration. <P>SOLUTION: In this steering angle detector, rotation of a steering shaft 3 corresponding to operation of a steering wheel 30 is transmitted to wheels 12, 12 for steering, and the steering angle of the vehicle steered by changing the orientations of the wheels 12, 12 is detected by determining the rotating angle of a plurality of rotations of the steering shaft 3. An oscillating angle of an oscillating arm 6 engaged with the steering shaft 3 and oscillated in accordance with rotation of the steering shaft 3 is detected by an oscillating angle sensor 7, and based on the detected oscillating angle, it is determined which region of the number of right and left rotations from the neutral position the steering shaft 3 is positioned. The rotating angle of the steering shaft 3 within the determined region is determined by a rotating angle sensor and the steering angle within the whole range of the steering angle is calculated. Due to this simple configuration, highly accurate detection of the steering angle can be performed in the whole range of the steering angle. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a steering angle detection device capable of accurately detecting a steering angle of a vehicle with a simple configuration.

  Steering of a vehicle transmits a rotation operation of a steering wheel, which is a steering member, to a steering mechanism via a steering shaft connected to the steering wheel, and changes the direction of the steering wheel by the operation of the steering mechanism. Is done. The steering angle (hereinafter referred to as the steering angle), which is the direction of the steering wheel that changes in accordance with the operation of the steering wheel, is important information for various types of control of the vehicle. Hereinafter, it is desired to detect with high accuracy over the entire steering angle range.

  The steering angle of a vehicle is generally obtained by detecting the rotation angle of a steering shaft, which is a rotating shaft that rotates a plurality of times according to the operation of the steering wheel, over the entire steering angle range. The steering wheel is normally configured to rotate 3 to 5 in order to steer over the entire steering angle range, and in order to detect the rotation angle of the steering shaft over the entire steering angle range, A rotation angle sensor capable of detecting an angle in the range of 1800 ° is required. The rotation angle sensor includes, for example, a speed reducer for converting a plurality of rotations into one rotation, and is configured to detect a rotation angle within one rotation after the conversion, and includes a sensor main body and peripheral members. There is a problem that the configuration becomes complicated.

In order to solve this problem, a steering angle detection device that detects the steering angle by detecting the rotation angle of the steering shaft over the entire steering angle range with a simple configuration has been proposed (for example, patents). Reference 1).
JP 2005-114676 A

  The steering angle detection device of Patent Document 1 is an electric power steering device configured to transmit the rotational force of a steering assist motor to a steering shaft via a worm and a worm wheel. A swivel-shaped groove is engraved, and the tip of a swing arm with a base attached to the input end of the rotary potentiometer is engaged with the groove. The swing angle of the swing arm as the worm wheel rotates Is detected, the rotation angle of the steering shaft over the entire steering angle range is obtained, and the steering angle is detected.

  However, the rudder angle detection device of Patent Document 1 is configured to detect the rotation angle of the steering shaft for 3 to 5 rotations by the limited swing of the swing arm that occurs in the formation range of the spiral groove. Therefore, there is a problem that the detection accuracy is not sufficient. In addition, there is a problem that the range of application is limited to a steering device including a worm and a worm wheel.

  The present invention has been made in view of such circumstances, and can detect the rotation angle of the rotating shaft over the entire steering angle range with high accuracy and can detect the steering angle of the vehicle with a simple configuration with high accuracy. An object is to provide an apparatus.

  The steering angle detection device according to the first aspect of the present invention transmits the rotation of the rotating shaft according to the operation of the steering member to the steering wheel and changes the direction of the wheel to determine the steering angle of the vehicle steered. In a rudder angle detection device that detects by detecting a rotation angle over a plurality of rotations, a rotation angle sensor that detects a rotation angle within one rotation of the rotation shaft, and a tip portion are engaged with the rotation shaft, A swing arm that swings around a shaft provided at the base in accordance with the movement of the engagement position accompanying the rotation of the rotary shaft, a swing angle sensor that detects a swing angle of the swing arm, and the swing And a calculation means for calculating the steering angle based on an angle sensor and an angle detected by the rotation angle sensor.

  In the rudder angle detection device according to a second aspect of the present invention, in the first aspect, the swing arm is engaged with a spiral groove formed on the outer peripheral surface of the rotary shaft, and the engagement position is changed with the rotation of the rotary shaft. It is configured to move in the axial direction.

  According to the first aspect of the present invention, the tip portion is engaged with the rotating shaft that rotates a plurality of times according to the operation of the steering member, and around the shaft provided in the base portion according to the movement of the engaging position accompanying the rotation of the rotating shaft. The swing angle of the swinging swing arm is detected by a swing angle sensor, and based on the detection result of the swing angle sensor, a rough region in the entire steering angle range, specifically, the rotating shaft is moved from the neutral position to the left and right. The rotation angle within one rotation of the rotation axis is detected by the rotation angle sensor, and the rotation angle within the region determined by the detection result of the rotation angle sensor is increased. The steering angle within the entire steering angle range is calculated for accuracy. The rotation angle sensor that detects the rotation angle within one rotation can detect the rotation with high accuracy with a simple configuration, and the swing angle sensor used to determine the number of rotations of the rotation axis is high. Since accuracy is not required, it is possible to detect the steering angle with high accuracy over the entire steering angle range with a simple configuration.

  According to the second invention, the swing arm is engaged with the spiral groove formed on the outer peripheral surface of the rotating shaft, and the engaging position is configured to move in the axial direction along with the rotation of the rotating shaft. In addition, since the rotation of the rotation shaft is directly transmitted to the swing arm, the swing of the swing arm is surely generated, and it is possible to accurately determine the rotation region of the rotation shaft.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof. FIG. 1 is a schematic diagram illustrating a configuration of an electric power steering apparatus including a steering angle detection apparatus according to the present invention.

  The illustrated electric power steering apparatus includes a rack and pinion type steering mechanism. The rack-and-pinion type steering mechanism crosses the rack housing 10 in the middle of the rack housing 10, which is supported in an axially movable manner in a rack housing 10 that extends in the left-right direction of a vehicle body (not shown). The pinion housing 20 has a known configuration including a pinion shaft 2 rotatably supported inside the pinion housing 20.

  Both ends of the rack shaft 1 projecting outward from both sides of the rack housing 10 are connected to left and right front wheels (wheels) 12 and 12 as steering wheels via separate tie rods 11 and 11. An upper end of the pinion shaft 2 protruding outward from the side is connected to a steering wheel 30 as a steering member via the steering shaft 3. A pinion (not shown) is formed in the middle of the pinion shaft 2 extending into the pinion housing 20, and the pinion is formed on the outer surface of the rack shaft 1 at an appropriate length at the intersection with the rack housing 10. Meshed with the rack teeth.

  The steering shaft 3 is rotatably supported inside a cylindrical column housing 31, and is attached to the interior of a vehicle compartment (not shown) while maintaining a tilted posture with the front facing down via the column housing 31. The pinion shaft 2 is connected to the projecting end of the steering shaft 3 below the column housing 31, and the steering wheel 30 is fixed to the projecting end.

  With the above configuration, when the steering wheel 30 is rotated for steering, this rotation is transmitted to the pinion shaft 2 via the steering shaft 3, and the rotation of the pinion shaft 2 is engaged with the pinion and the rack teeth. In this part, the rack shaft 1 is converted into movement in the axial length direction, and by such movement of the rack shaft 1, the left and right front wheels 12, 12 are pushed and pulled through the respective tie rods 11, 11 to steer. Is made.

  In the middle of the column housing 31 that supports the steering shaft 3, a torque sensor 4 that detects a steering torque applied to the steering shaft 3 by a rotation operation of the steering wheel 30 is provided, and a steering assist is provided below the torque sensor 4. A motor 5 is attached.

  The torque sensor 4 is a known twin resolver including two resolvers having different shaft angle multipliers (1/2 of the number of poles). The steering shaft 3 is divided into two upper and lower shafts, and the two shafts are coaxially connected by a torsion bar. A resolver is attached to each of the two shafts. The torque sensor 4 detects the rotation angles of the two axes by these two resolvers, calculates the relative angular displacement generated between the two axes according to the torsion of the torsion bar, and calculates the steering torque. ing. The detection signals from these two resolvers are obtained as signals in which the same number of waveforms as the shaft angle multiplier appear in one rotation, and by combining these two signals, the above-mentioned relative angular displacement is obtained, and the steering shaft A rotation angle within one rotation of 3 is obtained.

  The steering assisting motor 5 is attached to the outside of the column housing 31 with its axis substantially orthogonal, and, for example, a worm fixed to the output end extending inside the column housing 31 is fixedly fitted to the steering shaft 3 by external fitting. The rotation of the motor 5 is transmitted to the steering shaft 3 after being decelerated by the worm and the worm wheel.

  The electric power steering apparatus including such a steering assist motor 5 detects the steering torque applied to the steering wheel 30 by the torque sensor 4 and controls the steering assist motor 5 that is driven and controlled based on the detected torque. The rotational force is transmitted to the pinion shaft 2 via the steering shaft 3 to assist the steering performed as described above.

  The steering angle detection device according to the present invention provided in the electric power steering device as described above includes a rotation angle sensor that detects the rotation angle of the steering shaft 3 and a swing arm 6 that swings as the steering shaft 3 rotates. And a swing angle sensor 7 for detecting the swing angle of the swing arm 6.

  The rotation angle sensor is a sensor that can detect the rotation angle of the steering shaft 3 within a range of one rotation. As described above, when a twin resolver is adopted as the torque sensor 4, the rotation angle within one rotation of the steering shaft 3 can be obtained from the output signal of the torque sensor 4. In this embodiment, the torque sensor 4 is It can also serve as a sensor.

  The swing arm 6 and the swing angle sensor 7 are provided above the torque sensor 4. FIG. 2 is a cross-sectional view schematically showing the vicinity of the place where the swing arm 6 and the swing angle sensor 7 are disposed. As shown in FIG. 2, spiral grooves 3 a having a semicircular groove shape are engraved on the outer peripheral surface of the steering shaft 3 with a constant pitch.

  In the middle of the column housing 31, a mounting portion 32 of the swing angle sensor 7 is provided so as to project one part of the peripheral wall facing the formation area of the spiral groove 3a outwardly in an arch shape. The attachment portion 32 communicates with the outside through an opening that is substantially orthogonal to the axial direction of the column housing 31.

  The swing angle sensor 7 is, for example, a known rotary type including a resistance element to which a constant voltage is applied at both ends, and a sliding piece that rotates while being in contact with the resistance element inside a cylindrical housing. It is a potentiometer. Hereinafter, a rotary potentiometer will be described as an example. The swing angle sensor 7 includes an input shaft 70. One side of the input shaft 70 extending inward of the cylindrical housing is fixed to the sliding piece, and the other side is protruded to the outside of the housing. The rotation angle of the input shaft 70 is obtained by detecting the voltage between the one end of the resistance element and the sliding piece in proportion to the rotation of the sliding piece, and detecting the voltage between the two. It is configured as follows.

  As shown in FIG. 1, the swing angle sensor 7 is attached to a seating surface that borders the opening of the attachment portion 32, and a flat plate is formed at the tip of the input shaft 70 that protrudes inside the column housing 31 by this attachment. The base of the swing arm 6 is fixed. The tip of the swing arm 6 extends toward the inside of the column housing 31, and an engaging portion 60 protruding from the tip is engaged with the spiral groove 3a.

  In such a configuration, when the steering shaft 3 rotates, the engaging position of the engaging portion 60 moves in the axial direction, and the swing arm 6 provided with the engaging portion 60 by this movement is shown in FIG. As shown by the two-dot chain line, the rocking angle sensor 7 is swung over substantially the entire length of the formation area of the spiral groove 3a around the input shaft 70 of the rocking angle sensor 7. The swing angle sensor 7 detects a voltage corresponding to the swing angle.

  The detection result by the swing angle sensor 7 is given to the calculation unit 8 as shown in FIG. The calculation unit 8 is also given a detection result by the rotation angle sensor described above, and the calculation unit 8 calculates the rotation angle of the steering shaft 3 over the entire steering angle range based on these detection results, as will be described later. Obtain the steering angle of the vehicle.

  In the electric power steering apparatus provided with such a steering angle detection device, the steering shaft 3 rotates in the same direction in accordance with the rotation operation of the steering wheel 30 in the right direction or the left direction. It is converted into movement in the axial direction, and the left and right front wheels 12 and 12 are steered in the same direction as the operation direction of the steering wheel 30 as described above. At this time, the rotation angle sensor increases or decreases in proportion to the rotation angle of the steering shaft 3, and outputs a signal having a waveform that becomes 0 for each rotation. At the same time, the swing arm 6 engaged with the steering shaft 3 by the engaging portion 60 swings upward or downward. Since the electrical resistance of the resistance element of the swing angle sensor 7 changes according to the swing of the swing arm 6, the swing angle sensor 7 outputs a signal that increases or decreases according to the rotation angle of the steering shaft 3.

FIG. 3 is a relationship diagram between the rotation angle of the steering shaft 3 and the output values of the rotation angle sensor and the swing angle sensor 7 during such steering. In FIG. 3A, the horizontal axis indicates the rotation angle of the steering shaft 3, the vertical axis indicates the output value of the rotation angle sensor, and the minimum value on the horizontal axis indicates the steering corresponding to the maximum steering angle on the left side of the vehicle. The maximum rotation angle on the left side of the shaft 3 is −720 °, and the maximum value on the horizontal axis indicates the maximum rotation angle on the right side of the steering shaft 3 corresponding to the maximum steering angle on the right side of the vehicle. . The maximum value and the minimum value on the horizontal axis are not limited to ± 720 °, and may be values corresponding to the maximum steering angle of the vehicle, for example, ± 780 ° or ± 900 °. Good. As shown to Fig.3 (a), a rotation angle sensor outputs the signal which four waveforms which become 0 for every 1 rotation (360 degrees) within the whole steering angle range appear. FIG. 3A shows a sawtooth signal, but this signal waveform is obtained by calculating the original signal waveform of the sensor and is not limited to the sawtooth shape. The original signal waveform of the sensor differs depending on the type of sensor, and is, for example, a sin curve or a monotone gradient waveform. As shown in FIG. 3A, for example, when V ₁ is given as the output value of the rotation angle sensor, there are _four rotation angles of the steering shaft 3 of θ ₁ , θ ₂ , θ ₃ , and θ _4. .

The horizontal axis of FIG. 3B shows the rotation angle of the steering shaft 3 as in FIG. 3A, and the vertical axis shows the output value of the swing angle sensor 7. Since the swing of the swing arm 6 is caused by the movement of the engagement position of the engagement portion 60 to the spiral groove 3a provided on the steering shaft 3, the swing angle sensor 7 indicating the swing angle of the swing arm 6 is used. The output is a signal that increases and decreases proportionally over the entire steering angle range. For example, when V ₂ is given as the output value of the swing angle sensor 7, the rotation angle of the steering shaft 3 becomes one point in the entire steering angle range as shown in the figure. When the rotation angle of the steering shaft 3 over the entire steering angle range is divided into four regions corresponding to the first and second rotations on the left and right with the steering angle midpoint as the reference position, the obtained steering shaft 3 is obtained. It can be seen that the rotation angle is in the region of the first rotation in the right direction as shown in the figure. Using this result and the rotation angle of the steering shaft 3 by the rotation angle sensor, the rotation angle of the steering shaft 3 becomes one of θ ₃ , and the rotation angle of the steering shaft 3 over the entire steering angle range can be determined. it can. As a result, the steering angle of the vehicle can be obtained from the data of the correspondence relationship between the rotation angle of the steering shaft 3 and the steering angle over the entire steering angle range stored in the calculation unit 8 in advance. The neutral position of the steering shaft 3 is set to coincide with the steering angle midpoint.

  When the output value of the swing angle sensor 7 is near the boundary of each region, the steering shaft 3 can be obtained by using the output value of the rotation angle sensor and the output value of the swing angle sensor 7 at the region determination stage. It is possible to accurately determine the number of rotation regions in which. Of course, in the region determination stage, the output value of the rotation angle sensor and the output value of the swing angle sensor 7 may always be used to determine the rotation region of the steering shaft 3.

  As described above, in the steering angle detection device according to the present invention, the tip portion is engaged with the steering shaft 3 that rotates a plurality of times according to the operation of the steering wheel 30, and the engagement position is moved as the steering shaft 3 rotates. Accordingly, the swing angle of the swing arm 6 swinging around the shaft provided at the base is detected by the swing angle sensor 7, and a rough region in the entire steering angle range is detected by the detection result of the swing angle sensor 7. More specifically, while determining whether the rotation axis is in the left or right rotation region from the neutral position, the rotation angle within one rotation of the steering shaft 3 is detected by the rotation angle sensor, and the rotation angle sensor The rotation angle within the range determined by the detection result is obtained with high accuracy, and the steering angle within the entire steering angle range is calculated. The rotation angle sensor for detecting the rotation angle within one rotation can detect the rotation with high accuracy with a simple configuration, and the swing angle sensor 7 used for determining the number of rotations of the rotation axis is high. Since detection accuracy is not required, it is possible to detect the steering angle with high accuracy over the entire steering angle range with a simple configuration.

  The swing arm 6 is engaged with a spiral groove 3 a formed on the outer peripheral surface of the steering shaft 3, and is configured to swing according to the movement of the engagement position accompanying the rotation of the steering shaft 3. Since the rotation of the steering shaft 3 is directly transmitted to the swing arm 6, the swing arm 6 is reliably swung, and the steering shaft 3 is based on the output of the swing angle sensor 7 for detecting the swing angle. It is possible to accurately determine the number of rotations of the rotation.

  In the above embodiment, the swing arm 6 and the swing angle sensor 7 are provided above the torque sensor 4. However, the swing arm 6 and the swing angle sensor 7 are used for operating the steering wheel 30. Accordingly, it can be arranged at an appropriate part of the rotating shaft that rotates a plurality of times. For example, the steering shaft 3 may be extended downward, and the swing arm 6 and the swing angle sensor 7 may be provided in the extended portion. A swing arm 6 and a swing angle sensor 7 may be provided.

  Furthermore, in the present embodiment, the torque sensor 4 also serves as a rotation angle sensor, but a rotation angle sensor may be provided separately from the torque sensor 4.

  FIG. 4 is a cross-sectional view schematically showing the vicinity of the portion where the swing arm 6 and the swing angle sensor 7 are disposed in another embodiment. As shown in FIG. 4, winding springs 61 and 62 are interposed between the swing arm 6 and the housing of the swing angle sensor 7 so as to apply spring forces in different directions. The swing arm 6 is urged by these helical springs 61 and 62 in a neutral position direction indicated by a solid line in the drawing. Therefore, when the engaging position of the engaging portion 60 of the swing arm 6 moves upward or downward from the neutral position as the steering shaft 3 rotates, a downward or upward spring force acts on the swing arm 6. To do. Since other configurations are the same as those of the embodiment shown in FIG. 2, the same reference numerals as those in FIG. 2 are given to corresponding components, and detailed description of the configurations and operations is omitted.

  In this embodiment, for example, when the engagement position of the engagement portion 60 moves upward or downward during assembly and moves out of the formation area of the spiral groove 3a, the helical springs 61 and 62 are as described above. Since this spring force acts in the direction of the neutral position, the engaging portion 60 can return to a position where it can engage with the spiral groove 3a.

  In the above-described embodiment, the application example to the column assist type electric power steering apparatus in which the motor 5 is attached to the outside of the column housing 31 and the transmission shaft is configured to transmit is described. The angle detection device can also be applied to a rack-assist type electric power steering device in which a motor is attached to the rack housing 10 and is configured to transmit power to the rack shaft 1. Furthermore, the steering angle detection device according to the present invention can also be applied to a steer-by-wire type steering device that performs steering by driving a steering motor attached to a steering mechanism mechanically separated from the steering wheel. In addition, the present invention can also be applied to a manual steering device that performs steering only by a steering torque applied to the steering wheel by the driver.

It is a mimetic diagram showing composition of an electric power steering device provided with a rudder angle detection device concerning the present invention. It is sectional drawing which shows roughly the arrangement | positioning site | part vicinity of a rocking | swiveling arm and a rocking angle sensor. FIG. 4 is a relationship diagram between a rotation angle of a steering shaft and output values of a rotation angle sensor and a swing angle sensor. It is sectional drawing which shows schematically the arrangement | positioning site | part periphery of the rocking | swiveling arm and rocking angle sensor in other embodiment.

Explanation of symbols

3 Steering shaft (rotating shaft), 3a Spiral groove, 4 Torque sensor (rotation angle sensor), 6 Swing arm, 60 Engagement section, 7 Swing angle sensor, 8 Calculation section (Calculation means), 12 Front wheel (wheel) , 30 Steering wheel (steering member)

Claims (2)

  The rotation of the rotating shaft according to the operation of the steering member is transmitted to the steering wheel, and the steering angle of the vehicle steered by changing the direction of the wheel is detected by obtaining the rotation angle over a plurality of rotations of the rotating shaft. In the rudder angle detection device, a rotation angle sensor that detects a rotation angle within one rotation of the rotation shaft, and a tip portion of the rotation shaft are engaged, and the engagement position is moved along with the rotation of the rotation shaft. The swing arm swings around the shaft provided at the base, the swing angle sensor for detecting the swing angle of the swing arm, the detection angle by the swing angle sensor and the rotation angle sensor. A rudder angle detection device comprising: a calculation unit that calculates the steering angle based on the steering angle.   2. The swing arm is engaged with a spiral groove formed on an outer peripheral surface of the rotating shaft, and the engaging position is configured to move in the axial length direction as the rotating shaft rotates. The rudder angle detection device described.

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