JP2014198523A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of facilitating an operation for abutting on and separating from a steering wheel while suppressing cost in a steering device for steering a vehicle steering wheel.SOLUTION: A steering device 12 includes: a base part 20 mounted to a vehicle body side; a driving motor 24 fixed to the base part; and a transmission mechanism for transmitting rotating force of the driving motor 24 to a steering wheel 18. The transmission mechanism includes a belt part 36 and a support part serving as abutment means abutting to the steering wheel 18 to transmit the rotating force of the driving motor. The steering device 12 includes a first link part 28a and a second link part 28b for moving the abutment means between an abutment position abutting on the steering wheel 18 and a retract position separating from the steering wheel 18.

Description

  The present invention relates to a steering device for steering a steering wheel of a vehicle.

  In the operations such as sowing, transplanting, setting up, culling, and material dispersal by agricultural vehicles, each process goes straight and parallel in order to improve the accuracy and efficiency of the work, and for the subsequent management and harvesting work. It is important to do it. Since these operations often take a long time and there are some operations that cannot be redone, the physical and mental burden on the worker is large and skill is required. Therefore, it is desired to develop a technique for automatically moving agricultural vehicles straight ahead.

  As a technique for controlling the automatic traveling of the vehicle, there are techniques as shown below. Patent Document 1 discloses an automatic steering system that controls a hydraulic cylinder of a power steering device, a manual steering mechanism that operates according to a steering force of a steering, an automatic steering mechanism that operates according to a signal from a controller, An automatic steering system that switches between a manual steering mechanism and an automatic steering mechanism in accordance with a signal from a controller is disclosed.

  Patent Document 2 discloses a traveling vehicle automatic steering apparatus that controls the operation of a forward / reverse motor connected to an intermediate shaft of a steering shaft via an electromagnetic clutch.

  Non-Patent Document 1 discloses a cylindrical rotating body that can be pressed against the steering wheel from the outside in the radial direction of the steering wheel, a motor that is directly connected to the rotating body, a housing that surrounds the motor, and a mounting portion that attaches the housing to the vehicle body. Are disclosed. This driving device executes automatic steering for steering the steering wheel by controlling the driving of the motor in a state where the rotating body is pressed against the steering wheel. By fixing the attachment portion to the steering shaft, it can be attached to an existing vehicle later. The rotating body protrudes from the housing and is provided integrally with the motor. As the housing moves relative to the mounting portion, the rotating body takes a position where it contacts the steering wheel and a position away from the steering wheel.

Japanese Patent Laid-Open No. 2003-261049 JP 2011-207407 A Nikon Trimble Co., Ltd., “AgGPS EZ-Steer Automatic Steering Assist System”, [online], search date March 12, 2013, Internet <URL: http://www.nikon-trimble.co.jp/products /machinecontrol/ez-s.html>

  In order to mount the automatic steering device described in Patent Literature 1 and Patent Literature 2 on an existing vehicle owned by the driver, it is necessary to replace a part of the steering mechanism. In addition to the manufacturing cost of the automatic steering device, Costs associated with installation work on existing vehicles increase.

  In the technique described in Non-Patent Document 1, when the steering wheel is steered while the rotating body is in contact with the steering wheel, a load from the motor is applied. Therefore, when the driver steers, the driver removes the rotating body from the steering wheel. Steer away. On the other hand, when performing automatic steering, the driver brings the rotating body into contact with the steering wheel. That is, since the driver performs the switching operation of the position of the rotating body, there is an effort. In the operation of switching the position of the rotating body described in Non-Patent Document 1, it is necessary to move the housing including the motor, and thus the burden on the driver is large.

  The present invention has been made in view of such a situation, and an object of the present invention is to bring the contact means into and out of the steering wheel while suppressing the cost associated with the mounting operation in the steering device for steering the steering wheel of the vehicle. The object is to provide a technique capable of facilitating the operation.

  In order to solve the above problems, an aspect of the present invention includes a base portion attached to the vehicle body side, a drive motor fixed to the base portion, and a transmission mechanism for transmitting the rotational force of the drive motor to the steering wheel. A steering apparatus provided. The transmission mechanism includes a belt portion driven by a drive motor and a support portion that supports the belt portion from the inner peripheral surface side. The belt portion is provided such that the outer peripheral surface side can be brought into contact with the steering wheel by the support portion.

  According to this aspect, the steering device can be easily attached to an existing vehicle. Further, in switching to the contact position and the retracted position, the contact means is moved by the moving mechanism, and the heavy driving motor is fixed to the base, so that the force required for the switching can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, in the steering apparatus which steers the steering wheel of a vehicle, the operation | movement which contact | abuts and leaves | separates a contact means to a steering wheel can be made easy, suppressing the cost accompanying attachment work.

It is a figure for demonstrating the vehicle automatic control apparatus 10 provided in the working vehicle 16. FIG. It is a figure for demonstrating the steering device of embodiment, and shows the state attached to the vehicle. It is a figure for demonstrating the structure of the steering device of embodiment. It is a figure for demonstrating the steering device of the 1st modification. It is a figure for demonstrating the steering device of the 2nd modification.

  The work vehicle may be superior in traction force and turning force as compared with a normal general vehicle, but may have low straight-ahead performance. The driver is forced to go straight ahead while looking back, in order to check the working state of the work implement provided at the rear of the work vehicle. Some farms have a length of more than 500 meters, and driving this distance straight places a heavy burden on the driver. If an automatic vehicle control apparatus for performing automatic driving of a vehicle can be attached to an existing work vehicle later, it is possible to reduce the cost without replacing parts. Therefore, in the embodiment, retrofitting is possible by attaching the steering device of the vehicle automatic control device so as to contact the steering wheel of an existing work vehicle. Further, the vehicle automatic control device can be detached and attached to another work vehicle.

  FIG. 1 is a diagram for explaining an automatic vehicle control apparatus 10 provided in a work vehicle 16. The work vehicle 16 is, for example, an agricultural tractor or a civil engineering work vehicle. The steering wheel 18 is provided in the vehicle cabin and is rotated by the driver. The steering wheel 18 is connected to a steering mechanism (not shown), and the steering mechanism converts the rotation of the steering wheel 18 into a steering motion of the front wheels.

  The steering mechanism includes a steering wheel 18, a steering shaft 17, and a gear device (not shown) that converts the movement of the steering shaft 17 into the movement of the front wheels. One end of the steering shaft 17 is connected to the steering wheel 18 so as to rotate together with the steering wheel 18, and functions as a rotating shaft that transmits the rotation of the steering wheel 18 to the gear device.

  The vehicle automatic control device 10 includes a steering device 12, a control unit 13, and an imaging unit 11. As shown in the figure, the steering device 12 is supported by the mounting portion 22 so as to be positioned on the radially outer side of the steering wheel 18 of the work vehicle 16. The attachment portion 22 is fixed to the vehicle body side, for example, a housing that covers the steering shaft 17.

  The imaging unit 11 is disposed on the upper part of the vehicle cabin. The image pickup unit 11 is a camera, and picks up images of the ground and the horizon in the traveling direction, which are targets for vehicle travel. The imaging unit 11 outputs the captured image to the control unit 13.

  The control unit 13 is connected to the steering device 12 by wire or wirelessly, and sends out a control signal for controlling the driving of the steering device 12. The control unit 13 is mounted on the vehicle body.

  The control unit 13 functions as an image processing unit that processes the captured image and functions as a traveling control unit that controls the traveling of the work vehicle 16. The control unit 13 includes a CPU that executes various arithmetic processes, a ROM that stores various control programs, a RAM that is used as a work area for data storage and program execution, a backup RAM that can retain stored contents even when the engine is stopped, etc. It comprises an A / D converter for converting analog signals input from a nonvolatile memory, an input / output interface, various sensors, etc. into digital signals, and a timer for timing.

  The control unit 13 detects a target tracking line that is a target of traveling from the captured image of the imaging unit 11 and performs control so as to travel along the target tracking line. The target tracking line is, for example, a field fence detected from a captured image.

  When the driver starts the engine of the work vehicle 16, the control unit 13 detects the target tracking line from the captured image output from the imaging unit 11. The control unit 13 performs traveling control so that the work vehicle 16 goes straight along the target tracking line from the initial position of the work vehicle 16. For example, after the steering device 12 comes into contact with the steering wheel 18, the control unit 13 executes traveling control that follows the target tracking line.

  Drawing 2 is a figure for explaining steering device 12 concerning an embodiment. FIG. 2A shows the steering device 12 in the contact position with respect to the steering wheel 18, and FIG. 2B shows the steering device 12 in the retracted position with respect to the steering wheel 18. Note that the steering device 12 shown in FIGS. 2A and 2B shows a state where the cover is removed so that the internal structure can be seen.

  FIG. 3 is a schematic diagram for explaining the structure of the steering device 12. 3A shows the steering device 12 at the contact position, FIG. 3B shows the steering device 12 at the retracted position, and FIG. 3C shows the steering device 12 at the contact position. It is the schematic diagram which looked at the steering apparatus 12 from the side. 3A is a cross-sectional view taken along line AA of the steering device 12 shown in FIG. 3C, and FIG. 3B is a cross-section obtained by rotating the link portion 28 of FIG. 3A. FIG. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

  The steering device 12 shown in FIG. 2A has a first support part 26a and a second support part by rotation of the first link part 28a and the second link part 28b (referred to as “link part 28” if they are not distinguished from each other). 26b (referred to as “support portion 26” when these are not distinguished) protrudes toward the steering wheel 18, the belt portion 36 is in contact with the steering wheel 18, and the support portion 26 and the belt portion 36 are in the contact position. is there.

  In the steering device 12 shown in FIG. 2B, the support portion 26 and the belt portion 36 are retracted from the contact position shown in FIG. 2A, and are in the retracted position separated from the steering wheel 18.

  As shown in FIG.3 (c), the base 20 is comprised from two flat plates, and the link part 28 grade | etc., Is arrange | positioned among them. The base portion 20 is supported by the attachment portion 22 and attached to the vehicle body side. The base portion 20 is fixed to the attachment portion 22 so as not to move.

  As shown in FIG. 3A, the drive motor 24 is fixed to the base portion 20. The drive motor 24 is connected to the control unit 13 by wire or wirelessly, and rotates based on a control signal from the control unit 13. The drive motor 24 is electrically connected to the power supply unit of the vehicle.

  The rotational force of the drive motor 24 is transmitted from a first gear 42 coaxial with the drive motor 24 to a second gear 40 that meshes with the first gear 42. The third gear 38 is coaxial with the second gear 40 and rotates integrally with the second gear 40. The first gear 42, the second gear 40 and the third gear 38 are rotatably supported by the base 20. Thus, the rotational force of the drive motor 24 is transmitted to the third gear 38.

  The second gear 40 has a larger diameter than the first gear 42, and the rotational force received by the second gear 40 increases. The third gear 38 has a smaller diameter than the second gear 40. With such a gear diameter configuration, the rotational force of the drive motor 24 can be amplified.

  The belt portion 36 is endless and has an annular shape. The outer peripheral surface of the belt portion 36 is flat, but teeth are formed on the inner peripheral surface. The outer peripheral surface of the third gear 38 and the support portion 26 meshes with the inner peripheral surface of the belt portion 36. The rotational force of the drive motor 24 is transmitted from the third gear 38 to the belt portion 36. The support portion 26 supports the belt portion 36 from the inner peripheral surface of the belt portion 36. Since the support part 26 rotates with the belt part 36, friction is suppressed compared with the case where the support part 26 does not rotate. The rotational force of the drive motor 24 can be easily transmitted to the belt portion 36.

  The steering device 12 includes a second gear 40, a third gear 38, a belt portion 36, and a support portion 26 as a transmission mechanism for transmitting the rotational force of the drive motor 24 to the steering wheel 18. Of the transmission mechanism, the belt portion 36 and the support portion 26 are brought into contact with the outer ring portion of the steering wheel 18 and function as contact means for transmitting the rotational force of the drive motor 24. The contact of the support portion 26 with the steering wheel 18 is indirect via the belt portion 36. However, since the support portion 26 presses the belt portion 36 against the steering wheel 18, the support portion 26 also has the steering wheel. 18 is included in the contact means.

  The steering device 12 further includes a link portion 28 as a moving mechanism that moves the contact means between a contact position that contacts the steering wheel 18 and a retracted position that is separated from the steering wheel 18. The contact means that is moved to the moving mechanism and is brought into contact with the steering wheel 18 can be designed with a simple configuration of the support portion 26 and the belt portion 36.

  The link portion 28 connects the base portion 20 and the support portion 26. One end portion of the first link portion 28a is pivotally supported by the base portion 20, and the other end portion rotatably supports the first support portion 26a. One end portion of the second link portion 28b is pivotally supported by the base portion 20, and the other end portion rotatably supports the second support portion 26b. That is, the support part 26 moves according to the rotation of the link part 28. The link portion 28 moves the belt portion 36 to the contact position or the retracted position via the support portion 26.

  As shown in FIG.3 (c), the 1st link part 28a and the 2nd link part 28b are arrange | positioned up and down. As shown in FIGS. 3 (a) and 3 (b), the first link portion 28a and the second link portion 28b are arranged so as to intersect in the top view at both the retracted position and the contact position, and are supported at the contact position. The parts 26 approach each other from the retracted position.

  The first link part 28a is connected to the operation part 34 via the connection part 32a, and the second link part 28b is connected to the operation part 34 via the connection part 32b. The operation unit 34 is a lever for the driver to move the link unit 28.

  The first tension spring portion 30a biases the first link portion 28a at the contact position toward the retracted position, and the second tension spring portion 30b biases the second link portion 28b at the contact position toward the retracted position. To do. One end of the first tension spring portion 30 a and the second tension spring portion 30 b (referred to as “the tension spring portion 30” when these are not distinguished) is connected to the base portion 20 and the other end is connected to the trunk portion of the link portion 28. When the driver presses the operating portion 34 by the tension spring portion 30, the link portion 28 easily moves to the retracted position.

  A pair of loosening prevention pulleys 29 are provided on the base 20 and abut against the outer peripheral surface of the belt portion 36 so that the belt portion 36 does not loosen at the retracted position. By suppressing the looseness of the belt portion 36, the belt portion 36 is prevented from coming off.

  As shown in FIG. 2A, a locking mechanism 35 that locks the operating portion 34 at the contact position is provided. The locking mechanism 35 locks the operating portion 34 against the urging force of the tension spring portion 30 at the contact position. The locking mechanism 35 includes a rack gear 35a that moves in accordance with the push-pull operation of the operation unit 34, and a regulation unit 35b that meshes with the rack gear 35a.

  The restricting portion 35b restricts the movement of the rack gear 35a at the contact position. When the driver pushes the operation unit 34 with a force equal to or greater than a predetermined value, the restriction of the restriction part 35 b is released and the driver is moved to the retracted position by the tension spring part 30. The link portion 28 is rotated by the tension spring portion 30, the support portion 26 is retracted, the support portion 26 and the belt portion 36 are separated from the steering wheel 18, and the retracted position shown in FIGS. 2B and 3B is obtained. .

  On the other hand, if the driver pulls the operating portion 34 toward the steering wheel 18 from the retracted position, the link portion 28 rotates and protrudes via the connecting portion 32, and the outer peripheral surface of the belt portion 36 that is a contact means is directed to the steering wheel 18. Abut and become a contact position. In the contact position, the belt portion 36 transmits the rotational force of the drive motor 24 to the steering wheel 18. Thus, the steering device 12 operates so that only the contact means takes the contact position and the retracted position.

  In the steering device 12, the drive motor 24, the belt portion 36 that is a contact means, and the support portion 26 are separated. Therefore, the belt portion 36 and the support portion 26 may be moved when the steering device 12 is brought into contact with the steering wheel 18. On the other hand, the drive motor 24 is very heavy because it requires a driving force to rotate the steering wheel 18, but does not need to be moved and does not move while being fixed to the base 20. That is, the support portion 26 moves relative to the drive motor 24 and the base portion 20. Thereby, compared with operation which moves the drive motor 24 and the whole base 20 to the steering wheel 18, the operation force at the time of switching the contact means of the steering apparatus 12 to a contact position and a retracted position can be reduced.

  The belt portion 36 abuts the steering wheel 18 on a portion 36a stretched between the adjacent first support portion 26a and second support portion 26b. Thereby, the contact area of the belt part 36 to the steering wheel 18 is increased, a sufficient contact area can be secured, and the rotational force of the drive motor 24 can be transmitted to the steering wheel 18 with high accuracy. In particular, when the steering wheel 18 is eccentric with respect to the steering shaft 17 due to a dimensional error at the time of manufacture, the rotational position of the steering wheel 18 is brought into contact with a bendable belt portion 36 with a certain length. Regardless, it can be made to contact sufficiently.

  Further, by securing a sufficient contact area, the pressing force on the steering wheel 18 can be reduced, and the force required to move to the contact position can be reduced. That is, not only can the switching operation to the contact position and the retreat position be performed by the driver with the operation unit 34, but the switching can be easily automated with a small driving force. For example, by attaching a motor for moving the rack gear 35a back and forth and controlling the drive of the motor by the control unit 13, the switching to the contact position and the retracted position can be automated. Further, by reducing the pressing force on the steering wheel 18, the drive motor 24 can be reduced in size and weight.

  The restricting unit 35 b transmits the meshing position of the rack gear 35 a to the control unit 13. Thereby, the control part 13 detects whether the belt part 36 exists in a contact position or a retracted position. When the control unit 13 detects the contact position, the control unit 13 drives the drive motor 24 to execute the travel control. When the control unit 13 detects the position, the control unit 13 stops the drive motor 24 and stops the travel control.

  When the belt portion 36 moves to the retracted position, the drive motor 24 is automatically stopped when the driver pushes the operating portion 34 and moves the link portion 28 to the retracted position because the control unit 13 stops the rotation. Since the rotation of the motor 24 is stopped, the power source of the drive motor 24 can be saved.

  The steering device 12 is provided with a cover (not shown) so that no foreign matter is caught between the gears. Since the steering device 12 is provided with the support portion 26 and the belt portion 36 that move separately from the drive motor 24, a cover portion is provided for each. The first cover portion is fixed to the base portion 20 so as to cover at least the upper surfaces of the drive motor 24 and the third gear 38. The first cover part is provided with an opening through which the support part 26 and the link part 28 enter and exit. The second cover part covers at least the upper surface of the support part 26 and is supported by the first cover part. The second cover part is movable together with the support part 26 and is slidably supported by the first cover part.

  FIG. 4 is a view for explaining the steering device 112 of the first modified example. The steering device 112 of the first modification example has a reduced number of parts for the link portion 128 and the support portion 126 compared to the steering device 12 shown in FIG.

  The steering device 112 is fixed to the vehicle body side by the mounting portion 22 and is disposed on the radially outer side of the steering wheel 18. The steering device 112 is connected to the control unit 13 by wire or wirelessly, and the drive is controlled.

  The steering device 112 includes a base portion 120, a drive motor 124, a support portion 126, a link portion 128, an operation portion 134, a belt portion 136, a first gear 142, a second gear 140, and a third gear 138.

  The base portion 120 is attached to the vehicle body side via the attachment portion 22. The drive motor 124 is fixed to the base 120 and its rotation is controlled by a predetermined control unit 13. The rotational force of the drive motor 124 is transmitted to the belt portion 136 via the first gear 142, the second gear 140, and the third gear 138. The support portion 126, the belt portion 136, the first gear 142, the second gear 140, and the third gear 138 function as a transmission mechanism for transmitting the rotational force of the drive motor 124 to the steering wheel 18.

  The annular belt portion 136 and the columnar support portion 126 are in contact with the steering wheel 18 and function as contact means for transmitting the rotational force of the drive motor 124. The support part 126 is rotatably supported by the link part 128. The outer peripheral surface of the support portion 126 meshes with the inner peripheral surface of the belt portion 136, and supports the belt portion 136 from the inner peripheral surface side.

  The second gear 140 has a larger diameter than the first gear 142, and the rotational force received by the second gear 140 increases. The third gear 138 has a smaller diameter than the second gear 140. With such a gear diameter configuration, the rotational force of the drive motor 124 can be amplified and applied to the steering wheel 18.

  The outer peripheral side of the support portion 126 is formed by a dentable resin member 126a and is recessed when abutting against the steering wheel 18 as shown in FIG. In addition, by increasing the outer diameter of the support portion 126, the contact area between the steering wheel 18 and the belt portion 136 can be increased. The resin member 126a is, for example, a sponge or a rubber material.

  One end portion of the link portion 128 is pivotally supported by the base portion 120, and the other end portion rotatably supports the support portion 126. The rotation axis of the link portion 128 is coaxial with the third gear 138. The link portion 128 functions as a moving mechanism that moves the contact means between a contact position that contacts the steering wheel 18 and a retracted position that is separated from the steering wheel 18.

  The operation unit 134 is provided on the support unit 126 and functions as a lever that can be gripped by the driver. The driver holds the operation unit 134 and pulls the support unit 126 in the retracted position toward the steering wheel 18 to rotate the link unit 128. As a result, a contact position where the belt portion 136 and the support portion 126 contact the steering wheel 18 is taken, and movement is restricted at the contact position by a predetermined restricting portion.

  As described above, the steering device 112 according to the first modification only needs to move the contact means (the support portion 126 and the belt portion 136) that is separate from the drive motor 124. The operating force required for switching between the contact position and the retracted position can be reduced as compared with the case of moving them together. Further, the manufacturing cost can be reduced by reducing the number of parts of the steering device 112.

  FIG. 5 is a view for explaining a steering device 212 of the second modification. FIG. 5A shows the steering device 212 in the retracted position with respect to the steering wheel 18, and FIG. 5B shows the steering device 212 in the contact position with respect to the steering wheel 18.

  The steering device 212 is fixed to the vehicle body side by the mounting portion 22 and is disposed on the radially outer side of the steering wheel 18. The steering device 212 is connected to the control unit 13 by wire or wirelessly, and the drive is controlled.

  The steering device 212 includes a base part 220, a drive motor 224, a support part 226, a link part 228, an operation part 234, a belt part 236, a first gear 242, a second gear 240 and a third gear 238.

  The base portion 220 is supported by the attachment portion 22 and attached to the vehicle body side. The drive motor 224 is fixed to the link unit 228 and the rotation is controlled by the control unit 13. The rotational force of the drive motor 224 is transmitted to the belt portion 236 via the first gear 242, the second gear 240 and the third gear 238. The support portion 226, the belt portion 236, the first gear 242, the second gear 240, and the third gear 238 function as a transmission mechanism for transmitting the rotational force of the drive motor 224 to the steering wheel 18.

  The belt portion 236 and the support portion 226 are in contact with the steering wheel 18 and function as contact means for transmitting the rotational force of the drive motor 224. The support part 226 is rotatably supported by the link part 228. The outer peripheral surface of the support portion 226 meshes with the inner peripheral surface of the belt portion 236, and supports the belt portion 236 from the inner peripheral surface side. By making the diameter of the support portion 226 larger than the third gear 238 on the drive motor 224 side, the contact area with the steering wheel 18 is ensured.

  The outer peripheral side of the support portion 226 is formed of a dentable resin member 226a, and is recessed when abutting against the steering wheel 18 as shown in FIG. The support part 226 is connected to the link part 228 and moved to the contact position and the retracted position.

  The link part 228 is formed in a flat plate shape and supports the drive motor 224 and the third gear 238. That is, the link part 228 functions as a base plate for the drive motor 224. The link portion 228 functions as a moving mechanism that moves the contact means between a contact position that contacts the steering wheel 18 and a retracted position that is separated from the steering wheel 18. One end portion of the link portion 228 is pivotally supported by the base portion 220, and the other end portion rotatably supports the support portion 226.

  The operation unit 234 is provided on the support unit 226 and functions as a lever that can be gripped by the driver. The driver holds the operation unit 234 and pulls the support unit 226 at the retracted position shown in FIG. 5A toward the steering wheel 18. Then, the link portion 228 is rotated by the rotation shaft 228a, and a contact position where the belt portion 236 and the support portion 226 contact the steering wheel 18 is taken. The predetermined restricting portion restricts the rotation of the link portion 228 at the contact position. The rotation axis 228 a of the link part 228 is parallel to the rotation axis of the support part 226.

  Since the shaft of the third gear 238 and the rotation shaft 228a of the link portion 228 are different, the rotation shaft 228a can be designed in a simple structure. Even if the link portion 228 is rotated, the positions of the support portion 226 and the third gear 238 do not change, so that the belt portion 236 is configured not to loosen.

  The drive motor 224 and the third gear 238 are arranged in the vicinity of the rotation shaft 228a of the link portion 228, and are configured so that the rotational force necessary for rotating the link portion 228 does not increase. For example, the interval between the drive motor 224 and the rotation shaft 228a is set to be equal to or less than half of the interval between the support portion 226 and the rotation shaft 228a. More preferably, the distance between the drive motor 224 and the rotation shaft 228a is set to be one third or less of the distance between the support portion 226 and the rotation shaft 228a.

  Since the steering device 212 of the second modified example can be manufactured with a simple configuration with a reduced number of parts, the manufacturing cost can be reduced. Further, by using the belt portion 236, the rotational force of the drive motor 224 can be amplified with a simple configuration, and the drive motor 224 can be downsized. By reducing the size of the drive motor 224, it is possible to reduce the labor of the switching operation of the contact means by the driver.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements, and such modifications are also within the scope of the present invention.

  In the embodiment, the tension spring portion 30 is shown as means for urging the support portion 26 to the retracted position, but the present invention is not limited to this mode. For example, a tension spring that connects the operation unit 34 and the base 20 may be provided to urge the operation unit 34 in the contact position to the retracted position. In addition, a tension spring that connects the rack gear 35a and the base 20 may be provided to bias the rack gear 35a at the contact position to the retracted position. Accordingly, if the restriction of the restriction portion 35b at the contact position is released, the support portion 26 can be automatically moved to the retracted position by the biasing force of the tension spring.

  In the embodiment, the control unit 13 that controls the drive motor 24 has been configured to perform travel control based on the captured image of the imaging unit 11, but is not limited to this mode. For example, the control unit may be connected to a GPS (Global Positioning System) receiver provided in the work vehicle 16 and perform travel control based on the position information of the work vehicle 16 acquired by the GPS receiver.

  DESCRIPTION OF SYMBOLS 10 Vehicle automatic control apparatus, 12 Steering device, 16 Work vehicle, 18 Steering wheel, 20 Base part, 22 Mounting part, 24 Drive motor, 26a 1st support part, 26b 2nd support part, 28a 1st link part, 28b 2nd Link part, 29 Loosening prevention pulley, 30a First tension spring part, 30b Second tension spring part, 32 connecting part, 34 operation part, 35 locking mechanism, 36 belt part, 38 third gear, 40 second gear, 42 First gear.

Claims (5)

A base attached to the vehicle body,
A drive motor fixed to the base;
A transmission mechanism for transmitting the rotational force of the drive motor to a steering wheel,
The transmission mechanism is
A belt portion driven by the drive motor;
A support portion for supporting the belt portion from the inner peripheral surface side,
The steering device according to claim 1, wherein the belt portion is provided such that an outer peripheral surface side can be brought into contact with a steering wheel by the support portion.   The steering apparatus according to claim 1, further comprising a moving mechanism that moves the belt portion between a contact position that contacts the steering wheel and a retracted position that is separated from the steering wheel. The support part has a first support part and a second support part,
The moving mechanism is
First moving means for moving the first support part;
Second moving means for moving the second support part,
The steering device according to claim 2, wherein the belt portion abuts against a steering wheel a portion stretched between the adjacent first support portion and the second support portion. A cover part covering the base part;
The cover part is
A first cover portion fixed to the base so as to cover the drive motor;
The steering apparatus according to claim 1, further comprising: a second cover portion that covers the support portion and moves together with the support portion. A base attached to the vehicle body,
A drive motor;
A belt portion for transmitting the rotational force of the drive motor to a steering wheel;
A support portion for supporting the belt portion from the inner peripheral surface side;
A moving mechanism for connecting the base and the support,
The steering mechanism characterized in that the moving mechanism moves the belt portion and the support portion between a contact position where the belt portion and the support portion are in contact with a steering wheel and a retracted position separated from the steering wheel.