JP2009006843A - Steering mechanism of working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering mechanism of working vehicle capable of performing a smooth steering work and preventing an erroneous operation of a steering switch by carrying out a steering running operation through an operation of the steering switch arranged at a steering wheel only under a working running mode. <P>SOLUTION: There is provided a steering mechanism for a working vehicle for steering front wheels 2 through a power steering unit 11 by a turning operation of a steering wheel 6, wherein the steering mechanism is provided with a mode changing-over means 32 for changing-over a working running and an on-road running. The power steering unit 11 is operated through an operation of a steering operation switch 16 arranged at the steering wheel 6 when the working is carried out to steer the front wheels 2 on the basis of a changing-over operation of the mode changing-over means 32 and additionally at the time of on-road running operation, and the power steering unit 11 is operated exclusively through a turning operation of the steering wheel 6 to steer the front wheels 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a steering mechanism in a work vehicle such as a tractor or a rice transplanter.

Conventionally, a steering switch that operates the hydraulic power steering unit and steers the front wheels by gripping and turning the steering handle has been provided with a switch that can be operated by a remote control, so that the steering handle can be switched without turning. A steering mechanism of a mobile agricultural machine (work vehicle) that operates a power steering unit to steer a front wheel by operating a switch is already known (see, for example, Patent Document 1).
JP-A-2-11472

The steering mechanism of a work vehicle disclosed in Patent Document 1 has an advantage that it is possible to arbitrarily select steering by a steering handle turning operation and steering by a changeover switch operation.
However, in the above steering mechanism, the changeover switch that operates the valve of the power steering unit is a type that is operated remotely from outside the machine, so it is difficult to perform radio control operation with the changeover switch while in the control section, etc. There are disadvantages.
In addition, the changeover switch can be operated in either road driving (high speed driving) or work driving (low speed driving). There are problems such as easy turning.
In view of the above circumstances, the present invention is provided with mode switching means for switching the traveling mode between work traveling and road traveling on the steering mechanism, and is operated by operating a steering switch (switching switch) provided on the steering wheel only in the working traveling mode. By making the direction travel, it is intended to prevent the steering switch from being erroneously operated, and to smoothly perform the turning operation in which the raising / lowering operation of the tillage working machine is performed at the same time.

  In order to solve the above problems, a steering mechanism for a work vehicle according to the present invention is a steering mechanism for a work vehicle in which a front wheel 2 is steered via a power steering unit 11 by a turning operation of a steering handle 6. And a mode switching means 32 for switching between road running and road driving. Based on the switching operation of the mode switching means 32, the power steering unit 11 is operated by operating the steering switch 16 provided on the steering handle 6 at the time of work. The vehicle is characterized in that the front wheel 2 is steered by operating the power steering unit 11 exclusively by a turning operation of the steering handle 6 during steering on the road.

The work vehicle steering mechanism according to the present invention has the following effects. That is, the front wheels can be steered by operating the steering switch provided on the steering handle in a state where the mode switching means provided on the steering mechanism is switched from the road running mode to the work running mode, so that the tilling work or the like is performed on the field. In such a case, turning in the direction of work is performed by simply operating the steering switch with a finger while holding the steering handle with one hand without requiring the steering handle to rotate. Can do.
Also, when driving on the road by switching to the road driving mode by the mode switching means, even if the steering switch provided on the steering handle is operated unexpectedly, the operation by the steering switch is disabled, so the aircraft turns rapidly. Can be prevented.

  An embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a tractor shown as an example of a work vehicle. The tractor 1 has an engine 4 mounted on a front portion of a traveling machine body 3 having left and right front wheels 2 and a rear wheel 2a, and is covered with a bonnet 5, and a steering handle behind the tractor 1. 6 and a seat 6a, etc., are disposed so as to be covered with a cabin 8, and a three-point link type lifting mechanism 9 for mounting a work machine such as a tillage device is provided at the rear of the machine body.

The tractor 1 includes a steering mechanism 10 having a steering handle 6. A steering shaft 12 is erected from an all-hydraulic power steering unit 11 installed in the traveling body 3 at the rear of the bonnet 5. 6 is attached and supported.
The steering mechanism 10 sends pressure oil from the hydraulic pump 13 to the power steering unit 11 and switches hydraulic oil that is switched in conjunction with the turning operation of the steering handle 6 in the same manner as in the conventional mechanism. The left and right front wheels 2 can be rotated in the steering direction of the steering handle 6.

  In the steering mechanism 10, a steering switch 16 including a seesaw operation type push button switch is provided on the steering handle 6, and an electric drive mechanism 17 provided in the middle of the steering shaft 12 is operated by a microcomputer unit 19 by operating the steering switch 16. It is provided so that it can be operated via.

  As shown in FIGS. 2 and 4, the steering switch 16 connected to the microcomputer unit 19 is connected to the right arm portion of the steering handle 6 having a ring shape with the thumb in the vertical direction by one hand holding the ring portion. It is provided so that the push operation can be performed easily. The steering switch 16 of the embodiment can cause the electric drive mechanism 17 to perform a right steering operation, which will be described later, when the upper portion is pushed, and can cause the electric drive mechanism 17 to be left-steered when the lower portion is pushed.

As shown in FIG. 3, the electric drive mechanism 17 divides the steering shaft 12 into an upper steering shaft 12 a and a lower steering shaft 12 b, and both shafts are connected via an electromagnetic clutch 20 so as to be intermittent. The driven gear 21 is attached and fixed to the lower steering shaft 12b, and the drive gear 22 meshed with the driven gear 21 is driven by the electric motor 25 connected to the microcomputer unit 19 via the electromagnetic clutch 23.
When the lower steering shaft 12b is rotated by the electric motor 25, the electromagnetic clutch 20 has a function of operating the clutch so as not to rotate the upper steering shaft 12a, and the electromagnetic clutch 23 is operated by the electric motor 25. When the steering wheel 6 is stopped, it has a clutch function that is turned off so as not to rotate the electric motor 25 even if the steering handle 6 is rotated.

With this configuration, the driver switches the mode switching means described later to the work travel mode, and performs the work travel in a state where the steering handle 6 is gripped and the body is in a stable posture. Then, when it is desired to carry out turning from straight running, if the upper part of the steering switch 16 is pressed with one hand holding the steering handle 6, the electric motor 25 rotates and the lower steering shaft 12b rotates to the right. The power steering cylinder 15 for the front wheels can be operated via the steering unit 11 to steer the left and right front wheels 2 in the right direction.
Further, when the lower part of the steering switch 16 is pushed, the electric motor 25 rotates in the reverse direction and the lower steering shaft 12b is rotated counterclockwise to operate the power steering cylinder 15 of the front wheel via the power steering unit 11, and the left and right front wheels 2 are moved to the left. Steer in the direction.

  Next, the operation panel unit 26 of the control unit 7 will be described with reference to FIGS. The control panel portion 26 is configured in the vicinity of the steering handle 6 at the rear portion of the bonnet 5. The engine accelerator lever 27 and the work implement elevating lever 29 are put on the cover portion that surrounds the upper steering shaft 12 a, and the steering handle 6 is handed. It can be operated freely. The work implement elevating lever 29 is operated in the vertical direction to operate a work implement hydraulic cylinder (not shown) to move the elevating mechanism 9 up and down to raise and lower the work implement such as a tillage device.

Further, the control unit 7 includes a foot pedal type main clutch 30 below the control panel unit 26, and a clutch that turns off the driving of the electric motor 25 when the main clutch 30 is operated to cut off the power from the engine 4. A switch 31 is provided. Therefore, when an emergency stop is desired during work travel, the electric motor 25 can also be stopped simultaneously by a stepping operation of the main clutch 30 that turns off the travel power.
In addition to the generally provided instruments and switches, the control panel unit 26 is provided with a mode switch 32 as mode switching means for switching the traveling mode between the road traveling and the working traveling, in the vicinity of the work implement lifting lever 29. It is provided and connected to the microcomputer unit 19.

As shown in FIG. 4, the microcomputer unit 19 connects the steering switch 16, work implement lifting lever 29, mode switch 32 and clutch switch 31 on the input side, and electromagnetic clutches 20 and 23 and electric motor 25 on the output side. And connected.
The mode switch 32 can be installed as a single switch. In this embodiment, for example, as shown in Japanese Patent Application Laid-Open No. 2007-14278 filed by the present applicant, an existing control device is provided in the tractor 1. In addition, it is configured to be combined with a mode change switch (mode change means) for selectively changing the control mode between the running mode and the work mode.

That is, the control device prohibits control operations such as automatic tilling depth control that are not required when traveling on the road in the traveling mode, and enables operations such as automatic tilling depth control that are necessary during the traveling operation in the work mode. It is something that can be done.
Accordingly, when the mode switch 32 that also serves as the mode changeover switch is turned ON, the automatic plowing depth control or the like is enabled, and at the same time, the steering according to the present work mode required during the plowing work is enabled. In this work mode, the front wheels 2 can be steered by operating the steering switch 16. Further, when shifting to road running after finishing tillage work, the mode changeover switch is turned OFF to turn off automatic tilling control and the like, and at the same time, disable steering in the work mode and enable steering in the present traveling mode.

  Next, the mode of work travel by the tractor 1 having the steering mechanism will be described with reference to the timing chart shown in FIG. First, the tractor 1 that has entered the field switches the mode switch 32 from the road travel mode to the work travel mode, enables automatic tilling control and the like, and enables steering in the present work mode. As a result, the operator can perform the steering operation by simply pressing the upper or lower portion of the steering switch 16 with one finger without rotating the steering handle 6.

  That is, as shown in FIG. 5, when the operator turns from the straight-ahead working state to the left (turning the vehicle body) turning around the headland, the operator operates each switch as shown in FIG. 5. Turning can be performed according to the operation order and timing of each device operated based on the operation. First, prior to turning, the work implement lifting lever 29 is operated to the up side to raise the work implement from the ground surface. When the steering switch 16 is operated counterclockwise in this state, the electromagnetic clutch 20 is disengaged and the operating force on the steering handle 6 side is not transmitted, and the electromagnetic clutch 23 is disengaged and the electric motor 25 is rotated to rotate the lower steering shaft. The electric motor 25 is rotated while being transmitted to the 12b side.

As a result, the lower steering shaft 12b rotates counterclockwise through the engagement of the drive gear 22 and the driven gear 21, and the power steering cylinder 15 of the front wheel is actuated via the power steering unit 11 to turn the left and right front wheels 2 to the left and turn the machine body. Start running.
Even if the rotation of the electric motor 25 is continued during this turning, and the power steering cylinder 15 of the front wheel reaches the left stroke end, the electromagnetic clutch 23 has a torque limiter function. Overload is prevented.

  Next, the operator turns the steering switch 16 clockwise at the timing when the turning of the airframe is finished and the vehicle goes straight. As a result, the electric motor 25 rotates in the reverse direction to rotate the lower steering shaft 12b to the right side through the meshing of the drive gear 22 and the driven gear 21, and the power steering cylinder 15 of the front wheel is restored via the power steering unit 11, so that the left and right front wheels are restored. Return 2 to the straight state.

  When the operation of the steering switch 16 is stopped when the front wheel 2 returns to the straight traveling state, the rotation of the electric motor 25 is stopped and the straight traveling can be performed. At this time, the operator operates the work implement lifting lever 29 downward with one finger holding the steering handle 6, lowers the work implement again to the tillage work state, and continues the work.

  In this straight running state running, the operator exclusively operates the steering handle 6 to correct the direction of the machine body. At this time, the steering switch 16 is OFF, and the rotation of the steering handle 6 is transmitted to the lower steering shaft 12b via the electromagnetic clutch 20, so that steering of the steering wheel can be performed smoothly. The turning operation force of the steering handle 6 is prevented from being reversely transmitted to the electric motor 25 because the electromagnetic clutch 23 is disengaged.

  The tractor 1 that switches the steering mode switch 32 provided on the steering mechanism from the road running mode to the work running mode and operates the steering switch 16 provided on the steering handle 6 to steer the front wheels 2 is When plowing or the like is performed, the steering switch 16 is simply operated with a finger of one hand holding the steering handle 6 without requiring the steering handle 6 to rotate during the turning operation. It can be easily turned by the labor-saving operation.

  Further, as shown in the example, a steering switch 16 that electrically steers the front wheels 2 is provided on the steering handle 6 and a work implement elevating lever 29 is provided in the vicinity of the steering switch 16. The work implement elevating lever 29 can be easily and quickly operated with the finger. Accordingly, the fixed reciprocating rotation operation that causes the steering handle 6 to rotate approximately two times is eliminated to eliminate the hindrance when turning the aircraft, and the operator should focus on the work situation required when turning the vehicle. Can do.

  Further, since the road traveling is performed by switching to the road traveling mode by the steering mode switch 32, even if the steering switch 16 is unexpectedly operated when the steering handle 6 is rotated, the operation by the steering switch 16 is disabled. Malfunctions can be prevented. Further, if the steering during the work travel is performed by the electric motor 25 whose rotation speed can be freely changed, the steering adjustment for the turning travel can be easily performed.

  In addition, the operation by the tractor 1 is such that the operation pattern of operating the work implement elevating lever 29 to the up side when turning and then operating to the down side at the completion of turning is fixed. The operation pattern is repeated several times on the field, and the operation taught during that time can be stored in the microcomputer unit 19. As a result, the tractor 1 tractor 1 automatically raises and lowers the work implement from the next time only by raising the work implement elevating lever 29 without operating the steering switch 16. be able to. In other words, the turning state changes depending on the field condition, but if the teaching operation is performed about two to three times in the field, and the time, vehicle speed, etc. are input during that time, then the direction suitable for the field condition is obtained. The operation can be automated.

It is a side view of the tractor provided with the steering mechanism concerning the present invention. It is a top view which shows the structure of the steering handle | steering-wheel and control panel part of the tractor of FIG. It is a side view of a steering mechanism. It is a wiring diagram of a microcomputer unit. It is a time chart of work travel.

Explanation of symbols

1 Tractor (work vehicle)
2 Front wheel 3 Traveling machine body 6 Steering handle 11 Power steering unit 16 Steering switch 32 Mode switching means (mode switch)

Claims (1)

  In a steering mechanism of a working vehicle that steers the front wheels (2) via the power steering unit (11) by a turning operation of the steering handle (6), mode switching means (32) for switching between working running and road running on the steering mechanism. ), And based on the switching operation of the mode switching means (32), the power steering unit (11) is operated by operating the steering switch (16) provided on the steering handle (6) during the operation, thereby operating the front wheel (2). The steering mechanism for a work vehicle is characterized by operating the power steering unit (11) to steer the front wheels (2) exclusively by turning the steering handle (6) when traveling on the road.

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