JP4349031B2 - Vehicle steering system - Google Patents

Description

  The present invention relates to a vehicle steering apparatus including a wheel steering mechanism that is not mechanically connected to an operation member.

  In recent years, steer-by-wire type steering devices are frequently used in order to simplify the steering mechanism, reduce the number of parts associated therewith, reduce the weight of the vehicle body, and the like. Here, the steer-by-wire type steering device is a vehicle steering device that can steer the wheels without mechanically connecting an operation member such as a steering wheel to a steering mechanism such as a steering gear.

  Since the operating member is not mechanically connected to a steering mechanism such as a steering gear, the steering feeling is uncomfortable as compared with a steering device in which the operating member is mechanically connected to a steering mechanism such as a steering gear. Therefore, a reaction force motor that provides an appropriate reaction force is provided to give a natural steering feeling. Further, in order to detect the steering angle, it is necessary to provide a sensor such as a potentiometer on the operation member. Conventionally, an analog output sensor that detects and outputs an analog signal is often provided.

  For example, Patent Document 1 includes a sensor that detects a steering rotation angle of a steering wheel, a sensor that detects a vehicle speed, and a rotation angle sensor that detects a steering angle, and includes a steering rotation angle and a steering angle of the steering wheel. A steer-by-wire type steering device that generates an appropriate reaction torque that minimizes the deviation and returns the steering shaft to the neutral position is disclosed.

However, like a steer-by-wire type steering device, the steering angle of the operating member is electrically transmitted to the actuator via the arithmetic device, and converted into a steering angle by a steering mechanism such as a steering gear, When the output of the rotation angle sensor that detects the steering angle is a digital signal, conversion processing is not necessary, and the amount of calculation processing in the calculation device can be reduced. Therefore, it is also attempted to detect the steering angle with a digital output sensor that detects and outputs a digital signal such as a rotary encoder.
JP 2000-53008 A

  However, if the steering angle sensor is a digital output sensor, the reference point is detected when the power supply system fails or the engine is turned off and when the engine recovers from the failure or the engine is restarted. If the signal indicating this is not detected again, there is a possibility that the steering angle cannot be detected. Therefore, in consideration of safety, it is preferable to attach a digital output sensor so that the neutral position of the steering shaft, that is, the position where the wheel steering angle is zero can be reliably detected that the rotation angle is zero. .

  However, in general, digital output sensors clearly indicate the Z phase, which indicates the position at which the reference point is detected at the time of product shipment, by marking on the code wheel provided as the object to be detected. It is practically difficult to attach the rotation angle sensor so that the position of the steering shaft coincides with the neutral position of the steering shaft, and a detection error often occurs between the rotation angle of the steering shaft and the detection angle by the rotation angle sensor. For example, when using an optical rotary encoder, it is easy to provide markings and slits indicating the reference points on the code wheel that is the object to be detected, but when installing the code wheel, attach the marking position and slit position to the correct position. There is a problem that it is difficult to correctly adjust the marking position and the slit position after mounting.

  Also, analog output sensors are often used together to complement digital output sensors, but in order to perform accurate complementation, the marking position indicating the position for detecting the reference point of the analog output sensor and the reference of the digital output sensor It is necessary to match the slit position indicating the position where the point is detected. However, as described above, it is practically difficult to attach the sensor so that the position of the marking or the like for detecting the reference point coincides with the marking position indicating the position for detecting the reference point of the analog output sensor. There is a problem that it is difficult to adjust the deviation of the rotation angle detected by the both rotation angle sensors after the attachment.

  The present invention has been made in view of such circumstances, and a marking position indicating a neutral position for a steering shaft and a position for detecting a reference point for an analog output sensor are defined as a slit position indicating a position for detecting a reference point for a digital output sensor. It is an object of the present invention to provide a vehicle steering apparatus that can be easily mounted so as to coincide with the vehicle.

Vehicle steering apparatus according to a first invention to achieve the above object, detects a steering shaft coupled to the operating member of the vehicle, a housing for rotatably supporting the steering shaft, the rotation angle of the steering shaft a rotation angle sensor, a vehicle steering system that includes a wheel steering mechanism which is not the operating member and mechanically connected, the rotation angle sensor, a digital output sensor for outputting a digital signal corresponding to the rotation angle When, and a analog output sensor for outputting an analog signal corresponding to the rotation angle, wherein the housing a long opening in the circumferential direction of the housing, in preparation for inserting the fixing member of the rotation angle sensor The rotation angle sensor is a mark indicating a neutral position where the detection unit of the rotation angle sensor is provided on the steering shaft. In order to I, characterized in that it is fixed by the position adjustment in the length range of the opening.

In the vehicle steering apparatus according to the first aspect of the present invention, the housing has an opening having a predetermined length in the circumferential direction of the housing in order to insert a member such as a screw for fixing a detection portion for detecting the rotation angle of the steering shaft. from Rukoto with a hole, in the neutral position of the steering shaft, so that the detection unit is a reference point of the rotation angle sensor can be reliably detected, by moving the detector along the opening, screwing as possible out to adjust the position for fixing the detecting portion at the like. Therefore, even in digital output sensor, be an analog output sensor, Ru can steering shaft to detect reliably the reference point as long as the neutral position. The rotation angle sensor includes a digital output sensor and an analog output sensor that can obtain a high-accuracy output by adjusting the fixed position. Therefore, when the engine is turned off and restarted, or an electrical failure occurs. However, the analog output sensor can substitute for the digital output sensor, and a safer vehicle steering apparatus can be provided.

The vehicle steering apparatus according to the second invention, openings in the first shot Ming, 10/360 or 20/360 or less in length of the outer circumference length of the housing in cross-section perpendicular to the axis of the steering shaft It is characterized by having.

In the vehicle steering apparatus according to the second aspect of the present invention, the length of the opening for adjusting the fixed position of the rotation angle sensor is 10/360 or more of the outer peripheral length of the housing in a cross section perpendicular to the axis of the steering shaft. because it is within the range of 360 or less, it becomes possible to adjust the fixed position of the detector to fully absorb the mounting errors which can occur during the installation of the rotation angle sensor.

  According to the present invention, even a digital output sensor can reliably detect the reference signal as long as the steering shaft is in the neutral position, and can provide a safer vehicle steering apparatus.

  Also, by using the analog output sensor together with the digital output sensor, the analog output sensor can substitute for the digital output sensor even when the engine is turned off and restarted or when an electrical failure occurs. Therefore, a safer vehicle steering apparatus can be provided.

  FIG. 1 is a configuration diagram of a vehicle steering apparatus according to an embodiment of the present invention. In FIG. 1, the steering wheel (operation member) 1 is not mechanically connected to the steering gear 3, and the steering actuator 2 is driven according to the operation of the steering wheel 1.

  The steering gear 3 has a motion conversion mechanism that converts the rotational motion of the output shaft of the steering actuator 2 into the linear motion of the steering rod 7. Further, the movement of the steering rod 7 is transmitted to the wheel 4 through the tie rod 8 and the knuckle arm 9 to constitute a wheel steering mechanism. As the steering actuator 2, for example, an electric motor such as a brushless motor may be used as long as the movement of the steering actuator 2 can be converted into the turning angle of the wheel 4.

  The steering wheel 1 has a steering shaft 10 that is rotatably supported on the vehicle body side. A detection signal from the rotation angle sensor 11 of the steering shaft 10 and a vehicle speed detection signal from the speed sensor 13 are sent to a control device 12 constituted by a computer. The control device 12 calculates a target turning angle according to the detected rotation angle and vehicle speed. For example, the target turning angle is made proportional to the detected rotation angle, and the proportionality constant is decreased as the vehicle speed increases. In addition, a sensor that detects a running state other than the vehicle speed, for example, lateral acceleration or the like may be provided, and the target turning angle may be changed according to the detected lateral acceleration or the like.

  On the other hand, an actual steering amount sensor 14 such as a potentiometer for detecting the operation amount of the steering rod 7 is provided, and the detected signal is sent to the control device 12. The control device 12 drives the steering actuator 2 via the drive circuit 15 so that the deviation between the actual turning angle corresponding to the detected operation amount of the steering rod 7 and the target turning angle is eliminated.

  In addition, a reaction force actuator 18 that adds torque to the steering shaft 10 is provided in order to apply a steering reaction force required to steer the steering wheel 1. The reaction force actuator 18 is configured by an electric motor such as a brushless motor having an output shaft integrated with the steering shaft 10.

  The control device 12 calculates a target reaction force torque according to the detected rotation angle and the detected vehicle speed, and via the drive circuit 16 so that the calculated target reaction force torque is generated by the reaction force actuator 18. The reaction force actuator 18 is driven. The relationship between the target reaction torque, the rotation angle, and the vehicle speed is, for example, the relationship between the steering resistance torque from the road surface, the steering angle, and the vehicle speed that acts when the steering wheel 1 and the steering gear 3 are mechanically connected. Ask based. Further, a sensor that detects a running state other than the vehicle speed, such as lateral acceleration, may be provided, and the target reaction force torque may be changed according to the detected value.

  A torque sensor 17 that detects the reaction force torque transmitted by the steering shaft 10 is provided, and the detected reaction force torque value is sent to the control device 12. The control device 12 controls the drive current of the steering actuator 2 so that the generated steering force of the steering actuator 2 corresponds to the detected reaction force torque. That is, if the reaction torque corresponding to the operating force applied by the driver increases, the generated steering force of the steering actuator 2 is increased, and if the reaction torque decreases, the generated steering force of the steering actuator 2 is decreased. . By doing so, the steering actuator 2 is not driven in a state where the driver does not apply the operating force, and the wheel 4 returns to the straight traveling state by the self-aligning torque. The control system for the steering actuator 2 and the reaction force actuator 18 may be a known control system, and is not particularly limited as long as the steering actuator 2 can be driven according to the operation of the rotary operation member.

  Conventionally, an analog output sensor such as a potentiometer is used as the rotation angle sensor 11 of the steering shaft 10. However, in consideration of the use in calculation by the control device 12, it is not necessary to perform analog-digital conversion by using a digital output sensor.

  However, it is common to use an analog output sensor and a digital output sensor together so that the steering operation can be performed safely even when the engine is turned off and restarted or when an electrical failure occurs. is there. Hereinafter, a case where an analog output sensor as an analog output unit such as a potentiometer and a digital output sensor as a digital output unit such as a rotary encoder are used together as the rotation angle sensor 11 of the steering shaft 10 will be described.

  When using a digital output sensor, it is necessary to ensure that the reference signal can be detected. That is, once the power is turned off, the displacement angle cannot be detected unless the reference signal is detected again. Therefore, it is necessary to reliably detect the reference signal when the power is turned on again.

  In the present embodiment, as a neutral position of the steering shaft 10, a pin hole is formed at a position where the actual steering wheel is in a straight traveling state to serve as a mark for attaching the rotation angle sensor. The rotation angle sensor is also marked at a position where the reference signal is detected to be a mark for attachment. Two of the analog output sensor and the digital output sensor are attached to the steering shaft 10. A potentiometer is used as the analog output sensor, and an optical rotary encoder is used as the digital output sensor.

  FIG. 2 shows a perspective view of a potentiometer used as an analog output sensor. As shown in FIG. 2, a marking hole 25 (marking position) is provided as a position for detecting a reference signal on a housing 27 that houses a main body portion of the analog output sensor.

  FIG. 3 shows a schematic sectional view in a direction perpendicular to the rotation axis of the optical rotary encoder. As shown in FIG. 3, a code wheel 21 having a concentric slit 22 in the center rotates, and the rotation angle is detected by a detection unit 23. At the time of mounting, the steering shaft 10 is inserted into the slit 22 to fix the code wheel 21. The detection unit 23 is fixed to a housing that houses the steering shaft 10 by using a fixing member such as a screw. The code wheel 21 has a marking slit 24 at a position where a so-called Z phase is present. The Z phase means a reference point that exists only in one place in the code wheel 21, and a marking slit 24 (reference slit position) is provided so that a reference signal can be detected.

  FIG. 4 shows an attached state of the optical rotary encoder, FIG. 4 (a) is a plan view seen from the axial direction of the steering shaft 10, and FIG. 4 (b) is VV in FIG. 4 (a). Cross-sectional views are shown respectively. A shaded portion 31 in FIG. 4A indicates a pin to which the optical rotary encoder main body is attached via a pin hole provided in the steering shaft 10. The insertion direction of the pin 31 indicates the neutral position of the steering shaft. Even if it is attached so that the marking slit 24 of the code wheel 21 and the direction of the pin 31 coincide, an attachment error occurs in the attachment process.

  However, the mounting error angle β from the insertion direction of the pin 31 indicating the neutral position of the steering shaft 10 to the detection portion 23 for detecting the rotation angle of the steering shaft 10 provided on the inner surface of the housing, and the neutrality of the steering shaft 10 The attachment error angle α from the insertion direction of the pin 31 indicating the position to the position of the marking slit 24 of the code wheel 21 is a level of 10 degrees or less. Therefore, the position of the marking slit 24 of the code wheel 21 with respect to the detection unit 23 provided on the inner surface of the housing always exists within a range of (α + β) or less, that is, a central angle of 20 degrees or less.

  FIG. 5 shows a reference position adjusting mechanism in which a screw fixing hole 41 having a predetermined length in the circumferential direction is provided in a housing in which the detection unit 23 is provided. As shown in FIG. 5, the detection portion 23 provided on the inner surface of the housing 43 is temporarily fixed with a screw (fixing member) 42 to fix the detection portion 23 to the housing 43, so that the marking slit 24 of the code wheel 21 can be detected. The detection unit 23 is rotated around the steering shaft 10. FIG. 6 shows a state after the detection unit 23 is rotated and the angle of the detection unit 23 is adjusted. Note that the temporary fixing is not limited to the screw, and may be anything as long as the position of the detection unit 23 can be fixed after adjustment.

  As shown in FIG. 6, the screw 42 for fixing the detection unit 23 to the housing 43 slides on the screwing opening 41 with the rotation of the detection unit 23, and the marking slit 24 of the code wheel 21. Screw in the position where the direction of the pin 31 matches. In this way, the marking slit 24 of the code wheel 21 can be reliably detected by the detection unit 23 at the neutral position of the steering shaft 10, and the steering shaft 10 can be moved to the neutral position even with a digital output sensor. By doing so, the reference signal can be reliably detected, and a safer vehicle steering apparatus can be provided.

  The same process is performed for the potentiometer. Mark the angle at which the potentiometer reference signal is detected, and pin the steering shaft 10 and the potentiometer so that the pin hole of the steering shaft 10 matches the position of the marking hole 25 indicating the angle at which the potentiometer reference signal is detected. Use to fix.

  In the case of a potentiometer, even if there is an attachment error angle between the pin hole position of the steering shaft 10, that is, the neutral position of the steering shaft and the marking hole 25 of the potentiometer, it is an analog output. The angle can be detected. However, in order to match the angle at which the reference signal of the digital output type optical rotary encoder is detected, a screwing hole having a predetermined length in the circumferential direction is provided in the housing as in FIG. The screw that temporarily fixed the potentiometer is opened so that the position of the marking hole 25 of the potentiometer coincides with the position of the marking slit 24 of the code wheel 21 that indicates the angle at which the reference signal of the optical rotary encoder is detected. It slides along the hole and is screwed at a position that coincides with the direction of the marking slit 24 of the code wheel 21 that indicates the angle at which the reference signal of the optical rotary encoder is detected.

  By doing so, the position of detecting the reference signal of the optical rotary encoder and the position of the potentiometer marking can be made to coincide with the neutral position of the steering shaft 10, so when the engine is turned off and restarted, As long as the steering shaft 10 is in the neutral position, the reference signal can be reliably detected. Further, even when the electrical connection is broken, it is possible to back up using the detected value of the potentiometer, and it is possible to provide a safer vehicle steering apparatus.

  In addition, it is preferable that the screw opening hole portion 41 having a length in the circumferential direction provided in the housing 43 has a center angle of 20 degrees or less. The attachment error angle of the slit position or the marking position indicating the position where the reference signal of the rotation angle sensor is detected has a center angle of 10 degrees or less, so the sensor reference signal for the neutral position of the steering shaft 10 This is because the marking position indicating the position for detecting inevitably exists within the range of the central angle ± 10 degrees or less. Therefore, by providing a screw opening hole having such a length in the housing 43, the marking position indicating the position for detecting the reference signal of the rotation angle sensor is surely matched, and a digital output sensor is used. Even so, it is possible to adjust so that the reference signal can be reliably detected.

  As described above, according to the present embodiment, the screw is temporarily fixed to the outer peripheral portion of the housing, and the detection unit is rotated to thereby steer the marking position indicating the angle at which the reference signal of the rotation angle sensor is detected. The vehicle can be adjusted to be surely aligned with the neutral position of the shaft, and a safer vehicle steering apparatus can be provided.

It is a lineblock diagram of the steering device for vehicles concerning an embodiment of the invention. It is a perspective view which shows the marking position of a potentiometer. It is a schematic sectional drawing of the direction perpendicular | vertical to the rotating shaft of an optical rotary encoder. It is a figure which shows the attachment state of an optical rotary encoder. It is a figure which shows the reference position adjustment mechanism of a detection part. It is a figure which shows the state after position adjustment of an optical rotary encoder.

Explanation of symbols

1 Steering wheel (operation member)
DESCRIPTION OF SYMBOLS 10 Steering shaft 11 Rotation angle sensor 21 Code wheel 22 Slit 23 Detection part 24 Marking slit (reference slit position)
25 Marking hole (marking position)
31 pin 41 screw fixing hole 42 screw (fixing member)
43 Housing

Claims (2)

A steering shaft coupled to a vehicle operating member;
A housing that rotatably supports the steering shaft;
A rotation angle sensor for detecting a rotation angle of said steering shaft,
In a vehicle steering apparatus comprising a wheel steering mechanism that is not mechanically connected to the operation member,
The rotation angle sensor includes a digital output sensor that outputs a digital signal corresponding to the rotation angle, and an analog output sensor that outputs an analog signal corresponding to the rotation angle , and the housing is arranged in a circumferential direction of the housing. A long opening is provided for inserting the fixing member of the rotation angle sensor ,
The rotation angle sensor is fixed by adjusting the position within the length range of the opening to match the detection portion of the rotation angle sensor with a mark indicating a neutral position provided on the steering shaft. A vehicle steering system. The opening may, for steering vehicle according to claim 1 Symbol mounting and having an 10/360 or 20/360 or less of the length of the outer peripheral length of the housing in cross-section perpendicular to the axis of the steering shaft apparatus.

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