JP2005349965A - Steering device of industrial vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device that enables a steering wheel to be maintained in a predetermined condition and be rapidly turned from that condition according to the way a steering wheel is operated. <P>SOLUTION: This steering device includes a steering wheel sensor 14 for detecting the steering angle A of the steering wheel 5; a steering wheel sensor 8a for detecting the operating angle B of the steering wheel 8; and a controller 15 for controlling a drive 13 that drives and turns the steering wheel 5 according to the results detected by both sensors. The controller 15 sets as a reference operating angle C the operating angle B at which the steering angle A is within a predetermined range of steering angles. Thereafter, as long as the steering angle B is within a predetermined range of steering angles that is based on the reference operating angle C, the drive 13 is controlled so that the steering angle A is within the predetermined range of steering angles. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a steering device for an industrial vehicle including a steered wheel and a drive device that drives the steered wheel to turn according to a steering operation, and more particularly to a technique for improving operability.

  Conventionally, an industrial vehicle such as a forklift employs a steering device that turns a steering wheel provided on a vehicle body by a driving device according to a steering operation. When such an industrial vehicle travels on a rough road, the steering wheel may turn in contact with the unevenness of the travel path. For example, during straight traveling, steering is performed even though the driver does not operate the steering wheel. The wheel turns and the vehicle meanders. For this reason, the driver repeats fine steering wheel operations to suppress the meandering of the vehicle, but such an operation is a heavy burden on the driver. In view of this, techniques described in Patent Document 1 and the like to be described later have been proposed, thereby improving operability related to steering.

  Patent Document 1 discloses a technique for maintaining a steered wheel (steering wheel) at a neutral position regardless of the target steering angle when the target steering angle (target steering angle) is in the vicinity of the neutral position (straight forward position). Has been described. Patent Document 2 discloses a technique for returning a steering wheel (tire) to a steering angle corresponding to the steering wheel operating angle when the steering wheel (tire) is rotated by an external force during traveling with the steering wheel operating angle kept constant. Is described. Patent Document 3 describes a technique for holding the turning angle at the center of the steering angle when the turning angle (steering angle) is a value near the center of the steering angle (straight-ahead position) and is in the hand-off state. ing.

JP-A-61-215167 JP 2001-1933 A JP 2002-166843 A

  If the steering wheel can be maintained in the straight traveling position as described above, the straight traveling performance of the vehicle will be improved. However, if the steering wheel is slightly rotated from this state, the steering wheel will turn accordingly. It will end up. In particular, in a steering device that does not have a mechanical coupling mechanism between the steering wheel and the steering wheel, the steering wheel can be rotated unexpectedly because the steering wheel can be rotated even if the steering wheel is maintained in the straight traveling position. Can be considered. On the other hand, since it is also necessary for the steering wheel to turn slightly from the straight traveling position by practically operating the steering wheel, the steering wheel is forcibly prevented from rotating when the steering wheel is maintained at the straight traveling position. Such is not preferable.

  Accordingly, an object of the present invention is to provide a steering device that can maintain a steered wheel in a predetermined state such as a straight traveling position, and that can quickly turn the steered wheel according to a steering operation from the state. To do.

  In order to achieve the above object, the present invention comprises a steering wheel provided on a vehicle body so as to be able to turn, and a drive device that drives the steering wheel to turn, and the drive device steers the steering wheel according to a rotation operation of a steering wheel. In a steering device for an industrial vehicle that performs steering by turning a wheel, a steering wheel sensor that detects a steering angle of the steering wheel, a handle sensor that detects an operation angle of the handle, and a detection result of both the sensors A control device for controlling the drive device, wherein the control device uses the operation angle when the steering angle detected by the steering wheel sensor is within a predetermined steering angle range as a reference operation angle, and thereafter If the operation angle detected by the handle sensor is within a predetermined operation angle range with the reference operation angle as a reference, the drive device is controlled so that the steering angle is within the steering angle range. To adopt a configuration, wherein the door.

  According to the present invention as described above, after the reference operation angle is set, the steering angle is set to a predetermined value as long as the steering wheel is held so that the operation angle is within the operation angle range with respect to the reference operation angle. Steering wheels are maintained so that they are within the steering angle range. That is, since it is not necessary to move the steering wheel at all, the burden on the driver is reduced, and the steering wheel can be easily maintained in the steering state corresponding to the steering angle range. Further, if the steering wheel is rotated until the operating angle is out of the above operating angle range, the steering wheel is not maintained within the above steering angle range, and the steering wheel can be turned according to the steering operation. it can.

  Here, the steering wheel is provided so as to be able to turn left and right from a position facing the straight traveling direction of the industrial vehicle, and the steering angle range is left from the steering angle when the steering wheel faces the straight traveling direction. If the operating angle is within the above-mentioned operating angle range, the steered wheels can be maintained in a substantially straight traveling direction. Improves straight running performance.

  In the present invention, the control device is detected by setting means for setting the operation angle at the time when the steering angle is within the steering angle range for a predetermined time to the reference operation angle, and the handle sensor. Determining means for determining whether or not the operated angle is within the operating angle range based on the reference operating angle set by the setting means, and the operating angle is within the operating angle range by the determining means When it is determined that the steering angle is within the steering angle range, it is possible to employ a configuration including drive control means for controlling the drive device such that the steering angle falls within the steering angle range.

  According to this, if the state where the steering angle is within the steering angle range does not continue for a predetermined time, even if the steering angle is within the above steering angle range, the steering wheel is turned according to the steering operation. If the operation angle is maintained within the above-described operation angle range as long as it continues for a predetermined time, the steering angle can be set within the above-described steering angle range. In addition, since the operation angle when the steering angle is within the steering angle range continues for a predetermined time is set as the reference operation angle, frequent (unnecessarily) setting to the reference operation angle can be prevented. And there is no risk of reducing operability.

  As described above, according to the present invention, if the steering wheel is held so that the operation angle is within the operation angle range with respect to the reference operation angle, the steering angle is within the predetermined steering angle range. Since the steered wheels are maintained, the burden on the driver related to the steering wheel operation for maintaining the steered wheels can be reduced.

  Hereinafter, an embodiment in which the present invention is applied to a reach-type forklift will be described with reference to the drawings.

  As shown in FIG. 1, the reach forklift includes a pair of left and right reach legs 2 extending in the front-rear direction on the body frame 1, and is movable in the front-rear direction along the reach leg 2. A lift device 3 is provided. A front wheel 4 that is a driven wheel is provided at the front end portion of the reach leg 2, and a rear wheel 5 that serves as a driving wheel and a steering wheel is provided at the rear portion of the vehicle body frame 1. The rear part of the vehicle body frame 1 is covered with a bonnet 6, and a traveling motor 11 for driving the rear wheels 5 is accommodated therein.

A driver's seat 7 on which the driver gets on the side of the hood 6 is provided in the upper part of the bonnet 6, and a steering handle 8 for steering is rotatably provided at a position facing the driver's seat 7. The steering handle 8 has a built-in sensor 8a for detecting the rotation angle, that is, the operation angle. As shown in FIG. 2, the sensor 8a detects the position of the knob relative to the position where the knob is farthest when viewed from the driver's seat 7 as the operation angle B, and the position where the knob is farthest (operation angle B = 0). , A positive operation angle B is detected clockwise in a plan view and negative in a plan view counterclockwise. The output of the sensor 8a is transmitted to the steering control device 15 mounted on the vehicle body frame 1.
A floor 9 on which a driver who has boarded the driver's seat 7 puts his / her foot is disposed below the steering handle 8, and an operation panel 10 for operating the lift device 3 and the like is provided on the side of the lift device 3 of the driver's seat 7. ing.

A traction motor 11 that drives the rear wheel 5 as a driving wheel is housed in the bonnet 6, and the power of the traction motor 11 is transmitted to the rear wheel 5 via the drive device 12. The drive device 12 supports the rear wheel 5 and is supported by the vehicle body frame 1 in the bonnet 6 so as to be able to turn. The drive device 12 is also driven by the steering motor 13 housed in the bonnet 6 to turn.
The drive device 12 is provided with a sensor 14 that detects a turning angle of the drive device 12, that is, a steering angle. Here, since the rear wheel 5 and the drive device 12 turn integrally, the sensor 14 substantially detects the turning angle of the rear wheel 5, that is, the steering angle. That is, the sensor 14 corresponds to the steering wheel sensor in the present invention. As shown in FIG. 3, the sensor 14 detects the driving direction of the rear wheel 5 with respect to the position where the driving direction of the rear wheel 5 is directed in the straight forward direction as the steering angle A, and forward straight direction (steering angle A = 0), a negative steering angle A is detected clockwise in a plan view and negative in a plan view counterclockwise. Then, the output from the sensor 14 is transmitted to the steering control device 15.

As shown in FIG. 4, the steering control device 15 includes a setting unit 15a, a determination unit 15b, and a drive control unit 15c.
The setting unit 15a sets the reference operation angle C based on the steering angle A input from the sensor 14 and the operation angle B input from the sensor 8a. That is, it is determined whether the steering angle A is within the angle range of the angle As in the positive and negative directions around the steering angle A = 0. If the steering angle A is within the above angle range, the steering angle is determined by a timer. The time T in which the state where A is within the above angle range continues is counted. Then, it is determined whether or not the continuation time T exceeds a predetermined time Tst. When it is determined that the continuation time T has exceeded, the operation angle B at that time is set as the reference operation angle C. If the steering angle A is not within the above angle range, the steering angle A and the operation angle B are transmitted as they are to the drive control unit 15c without setting the reference operation angle C.
The determination unit 15b determines whether or not the operation angle B is within the angle range of the angle Bst in both positive and negative directions around the reference operation angle C set by the setting unit 15a. It is determined whether or not the difference B−C from the reference operation angle C is within an angle range of ± Bst, and the determination result is transmitted to the drive control unit 15c.
The drive control unit 15c controls the steering motor 13 based on the steering angle A, the operation angle B, and the determination result. That is, the drive control unit 15c operates the steering motor 13 so that the steering angle A is within the above angle range when the angle difference BC is within the above angle range. That is, when the steering angle A is smaller than the angle −Ast, the steering motor 13 is operated so that the rear wheel 5 turns in the direction in which the steering angle A becomes larger. When the steering angle A is larger than the angle As, the steering angle A The steering motor 13 is actuated so that the rear wheel 5 turns in the direction in which the angle becomes smaller. On the other hand, when the angle difference BC is not within the above angle range or when the steering angle A is not within the above angle range, the drive control unit 15c calculates the target steering angle At based on the operation angle B, The steering motor 13 is operated so that the steering angle A becomes the target steering angle At. Here, the target steering angle At is calculated by, for example, adding / subtracting an angle set according to the operation angle B (for example, an angle of 1/4 of the operation angle B) to the current steering angle A.

  Hereinafter, the flow of control by the steering control device 15 will be described with reference to FIG. In the figure, “S” means a process step related to control.

  When the steering angle A is detected (S1) and the operation angle B is detected (S2), the steering control device 15 determines whether or not the flag is set (S3). If it is not set (S3: NO), it is subsequently determined whether or not the steering angle A is within an angular range of -Ast <A <Ast (S4). If the steering angle A is within this angle range (S4: YES), it is determined whether or not the time T during which this state continues exceeds a predetermined time Tst (S5), and the time Tst must be exceeded. If (S5: NO), the timer is counted up (S6).

  If the time Tst is exceeded in S5 (S5: YES), the operation angle B at that time is set as the reference operation angle C (S7), and the flag is set (S8). If the flag is set in S8 or if it is determined that the flag is already set in S3 (S3: YES), the difference between the detected operation angle B and the reference operation angle C is -Bst < It is determined whether or not the angle is within the range of B−C <Bst (S9). If the angle difference BC is within this angle range (S9: YES), it is subsequently determined whether or not the steering angle A is within the angle range of -Ast <A <Ast (S10). If the steering angle A is within this angular range (S10: YES), the steering motor 13 is stopped (S11). If not within this angular range (S10: NO), the steering angle A is within this angular range. The steering motor 13 is operated so as to become (S12).

  Whether it is determined in S4 that the steering angle A is not within the above angle range (S4: NO), or whether the angle difference BC is not in the above angle range (S9: NO) in S9 In either case, the flag is cleared (S13), the timer is cleared (S14), and the target steering angle At is calculated based on the operation angle B (S15). Then, the steering motor 13 is operated so that the steering angle A matches the target steering angle At (S16).

  According to such an embodiment, the state where the steering angle A is within the angle range of −Ast <A <Ast continues for the time Tst, and after the reference operation angle C is set, the operation angle B and the reference operation are set. The steering wheel 8 is held so that the difference from the angle C is within the angle range of −Bst <B−C <Bst, that is, the operation angle B is within the angle range of C−Bst <B <C + Bst. If so, the rear wheel 5 is maintained so that the steering angle A falls within the angular range of −Ast <A <Ast. Therefore, since the rear wheel 5 can be maintained in a state of being substantially directed straight, the reachability of the reach type forklift is improved. Even after the reference operation angle C is set, if the steering handle 8 is rotated beyond the angle range of C−Bst <B <C + Bst, the rear wheel 5 turns according to the operation angle B of the steering handle 8. As a result, the rear wheel 5 can be quickly turned from a state in which the rear wheel 5 is directed straight. Further, when the state where the steering angle A is within the angular range of −Ast <A <Ast continues for the time Tst, the reference operation angle C is set, so that the steering angle A instantaneously satisfies −Ast <A <Ast. Even if the angle is within the angle range, the reference operation angle C is not set, and control based on the reference operation angle C is not performed. Therefore, the operability is not deteriorated because the reference operation angle C is frequently set.

It is a perspective view concerning the embodiment of the present invention. It is a schematic diagram concerning the embodiment of the present invention. It is a schematic diagram concerning the embodiment of the present invention. It is a functional block diagram concerning the embodiment of the present invention. It is a control flow figure concerning an embodiment of the present invention.

Explanation of symbols

1 Body frame 4 Front wheel (driven wheel)
5 Rear wheels (drive wheels and steering wheels)
DESCRIPTION OF SYMBOLS 8 Steering handle 8a Sensor 11 Traveling motor 12 Drive apparatus 13 Steering motor 14 Sensor 15 Steering control apparatus 15a Setting part 15b Determination part 15c Drive control part

Claims (3)

A steering wheel provided on a vehicle body so as to be able to turn, and a drive device that drives the steering wheel to turn. The drive device turns and drives the steering wheel according to a rotation operation of a steering wheel. In the steering device,
A steering wheel sensor for detecting a steering angle of the steering wheel, a handle sensor for detecting an operation angle of the steering wheel, and a control device for controlling the driving device based on detection results of the two sensors,
The control device uses the operation angle when the steering angle detected by the steering wheel sensor is within a predetermined steering angle range as a reference operation angle, and thereafter, a predetermined operation angle based on the reference operation angle. A steering apparatus for an industrial vehicle, wherein if there is an operation angle detected by the handle sensor within a range, the drive device is controlled so that the steering angle is within the steering angle range. Setting means for setting the operation angle at the time when the state where the steering angle is within the steering angle range continues for a predetermined time as the reference operation angle;
Determination means for determining whether or not the operation angle detected by the handle sensor is within the operation angle range based on the reference operation angle set by the setting means;
Drive control means for controlling the drive device so that the steering angle is within the steering angle range when the determination means determines that the operation angle is within the operation angle range. The steering device for an industrial vehicle according to claim 1.   The steering wheel is provided so as to be able to turn left and right from a position facing the straight traveling direction of the industrial vehicle, and the steering angle range is from the steering angle when the steering wheel is directed straight to the left and right. The steering device for an industrial vehicle according to claim 1 or 2, wherein the steering device is set in a range of a predetermined angle.

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