JP2000142449A - Steering device for running vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the steering device of a running vehicle which can move by a light operation force surely and miniaturize a car body. SOLUTION: A shifter case 18 is arranged nearly horizontally between a front wheel 7 and rear wheel 8 and supported to a car body frame turnably around the turning fulcrum 36 provided on the right/left center of the shifter case 18 and connected to a front relay rod 23 for connecting a steering operation tool with the front steering mechanism 20 of the front wheel 7 and also a position changeable moving body 13 is inserted in the shifter case 18 and the moving body 13 is connected to a rear relay rod 24 connecting with the rear steering mechanism 21 of the rear wheel 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering apparatus for a traveling vehicle, and more particularly, to a steering apparatus capable of switching a steering method of front wheel only, anti-phase steering, and in-phase steering.

[0002]

2. Description of the Related Art Conventionally, in a traveling vehicle used for farming or the like, in order to improve both workability in a field and traveling performance on a general road, steering of front wheels only, anti-phase steering, and same-phase steering are performed. The system is being switched.
For example, in an orchard, anti-phase steering is preferable in order to reduce the turning radius, and when escaping from a cliff or a ditch, the same-phase steering is preferable. From the viewpoint of stable running, front two-wheel steering is suitable.

[0003] For example, Japanese Patent Application Laid-Open No. 7-96853 discloses an example of a technique for switching a steering system.
In this technology, a tilting member that can be tilted back and forth in accordance with a steering operation is provided, and a connection position between the tilting member and a front steering mechanism and a rear steering mechanism is adjusted in a vertical relationship with respect to a tilt axis of the tilting member. Switching between the above-mentioned anti-phase steering, in-phase steering, and front two-wheel steering is achieved.

[0004]

However, the connecting positions in this case are located on the outer periphery of a disc-shaped tilting member having a diameter on the tilting axis, and the connecting positions are shifted in the tilting axis direction. Therefore, when the tilting member is tilted by the steering operation, a large torsion is generated on the tilting shaft, which not only requires an excessive operating force but also deteriorates the operating accuracy and the life of parts. there were. Also,
Since an extra space is required for tilting the tilting member back and forth, there is also a problem that the vehicle becomes large and mobility in a field or the like is reduced. The present invention has been made in view of the above points,
It is an object of the present invention to provide a steering device for a traveling vehicle that can move reliably with a light operating force and can reduce the size of a vehicle body.

[0005]

The present invention uses the following means in order to solve the above problems. That is, in claim 1, the shifter case is disposed substantially horizontally between the front wheel and the rear wheel, and is supported on the vehicle body frame so as to be rotatable around a rotation fulcrum provided at the center in the left and right direction of the shifter case. Connecting the shifter case to a steering relay and a front relay rod which is linked to a front steering mechanism of a front wheel, and fitting a movable body whose position can be changed into the shifter case, and connecting the movable body to a rear steering mechanism of a rear wheel. After linking with the relay rod.

According to a second aspect of the present invention, the shifter case and the movable body have an arc shape centered on a rear pivot shaft of the rear relay rod when the steering operating tool is in a straight-ahead position.

According to a third aspect of the present invention, an actuator is connected to the movable body so as to be movable, and the position of the movable body can be arbitrarily changed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 is a partial cross-sectional side view of a traveling vehicle according to the present invention, FIG. 2 is a partial cross-sectional view of the same, FIG. 3 is an enlarged cross-sectional plan view of a switching mechanism of the present invention, and FIG. 5 is an explanatory diagram of the positional relationship between the steering elements during straight running, FIG. 6 is an explanatory diagram of the positional relationship between the steering elements during front two-wheel steering, and FIG. 7 is a diagram illustrating the positional relationship between the steering elements during antiphase steering. FIG. 8 is an explanatory diagram of the positional relationship between the steering elements during the same-phase steering, and FIG. 9 is a control block diagram of the shifter case rotation angle and the rack position.

First, the overall configuration of a traveling vehicle according to the present invention will be described with reference to FIGS. Driver seat 2
Body frame 1 on which the transmission case 6 and the transmission case 35 are mounted
A front axle case 29 and a rear axle protruding left and right from the front differential 27 and the rear differential 28, respectively, are disposed at the front and rear portions of the front and rear differentials 27 and 28, respectively. A pair of left and right front wheels 7 and a pair of right and left rear wheels 8 are attached to the axles respectively supported by the case 30, and the front differential 27, the rear differential 28 and the transmission case 35 are connected by a universal joint 31, Front and rear wheels 7, 8
Is driven.

A steering wheel 1 is rotatably mounted on the body frame 16 in front of the driver's seat 26, and a control valve constituting a power steering device is disposed at a base of a handle shaft of the steering wheel 1. The control valve is connected to a hydraulic cylinder 9 arranged at the lower center of the vehicle body, and the cylinder rod 10 of the hydraulic cylinder 9 is expanded and contracted by the turning operation of the steering wheel 1. The front end of the cylinder rod 10 is a shifter case 1 rotatable by expansion and contraction of the cylinder rod 10.
8 is connected to a rear portion of the shifter case 18, and a front portion of the shifter case 18 is connected to a front steering mechanism 20 of a front wheel via a front relay rod 23.
Is linked to A rear relay rod 24 protrudes rearward from a rack 13 serving as a movable body slidably mounted in the shifter case 18.
4 is linked to a rear steering mechanism 21 of the rear wheel 8. The rotation of the shifter case 18 is transmitted to the left and right front wheels 7 and the left and right rear wheels 8 by these front and rear steering mechanisms 21 and 22 to control the directions of the front wheels 7 and the front wheels 8.

That is, the front steering mechanism 20
Is connected to the front end of the front relay rod 23 and swings around the support shaft 37 in accordance with the displacement of the front relay rod 23 in the front-rear direction, and extends right and left from the front bell crank 2. It has left and right tie rods 4 and front knuckle arms 33 connected to the left and right front wheels 7 and swinging around a rotation shaft 39 to change the directions of the left and right front wheels 7 according to the left and right displacement of each tie rod 4. And shifter case 1
When the pivot 8 rotates, the front relay rod 23 is displaced in the front-rear direction, and the directions of the left and right front wheels 7 change. The rear steering mechanism 21 is similar to the front steering mechanism 20,
A rear bell crank 3 that is connected to the rear end of the rear relay rod 24 and swings around a support shaft 38 in accordance with the displacement of the rear relay rod 24 in the front-rear direction, and left and right extending right and left from the rear bell crank 3 Tie rods 5 and left and right rear wheels 8
And the rear knuckle arm 34 that swings around the rotation shaft 40 and changes the direction of the left and right rear wheels 8 in accordance with the lateral displacement of each tie rod 5.
When 8 rotates, the rear relay rod 24 is displaced in the front-rear direction, and the directions of the left and right rear wheels change.

Next, the structure of the switching mechanism 22 of the steering system including the shifter case 18 will be described with reference to FIGS.
This will be described below. The shifter case 18 includes a shifter case front portion 18a having a semicircular shape in plan view and a bow-shaped shifter case rear portion 18b having left and right curved rearward, and the shifter case rear portion 18b is a steering wheel 1 serving as a steering operation tool. Is straight, and the rear relay rod 24 has an arc shape centered on the rear pivot shaft 24a. The upper pivot shaft 36a and the lower pivot shaft 3 are provided on the upper and lower surfaces of the shifter case rear portion 18b substantially at the center in the left and right directions.
6b are fixedly mounted, respectively, and the vertical rotation fulcrum shafts 36a, 3a
The turning fulcrum shaft 6 b is rotatably supported on the vehicle body frame 16.

A rack 13 is provided in the shifter case rear portion 18b, and the rack 13 is provided in the shifter case rear portion 1b.
8b, supporting shafts 25a, 41a, and 42a are fixed to the rack 13 in the vertical direction, and rollers 25, 41 comprising bearings are provided at upper and lower ends of the supporting shafts 25a, 41a, and 42a. , 42, and the rollers 25, 4
Reference numerals 1 and 42 are slidably fitted in the rail groove 19 in the vertical direction formed in the shifter case rear portion 18b. Note that the entire shifter case 18 can be vertically divided into two parts so that each member can be easily and quickly assembled and finely adjusted.

A motor 6 is fixedly provided as an actuator on the side of the shifter case front portion 18a.
The output shaft 6a extends to the inside of the shifter case front portion 18a, and the worm 14 is externally fitted and fixed to the tip of the output shaft 6a. An intermediate shaft 43 is vertically supported behind the worm 14, and a worm wheel 15 is fixed to a lower portion of the intermediate shaft 43 to mesh with the worm 14,
A pinion 12 is fixedly provided at substantially the center of the same intermediate shaft 43 in the vertical direction, and the pinion 12 meshes with the rack 13.

An angle detection sensor 17 composed of a potentiometer is disposed above the upper rotation fulcrum shaft 36a, and detects the rotation angle of the shifter case 18 from the rotation of the upper rotation fulcrum shaft 36a. Also, shifter case front 1
A rack position detection sensor 11 composed of a potentiometer is provided below 8a, and the rack position detection sensor 11 detects the angle of a shaft 46 supported inside the shifter case front part 18a above it. The shaft 46
A gear 45 is fixed on the upper side, and the gear 45
The position of the rack 13 in the shifter case 18 is detected by the rack position detection sensor 11 based on the number of rotations of the intermediate shaft 43 by the motor 6. be able to.

Accordingly, when the motor 6 is driven by an operation from the driver's seat, the pinion 12 is rotated, and the rack 13 slides in the shifter case 18 left and right, and is connected to the rear relay rod 24 at the connecting position ( The position of the support shaft 25a) can be changed. The position at this time is detected by the rack position detecting sensor 11 and fed back to the control circuit 47.

When the steering wheel 1 is rotated after the position of the support shaft 25a is determined, the cylinder rod 10 of the hydraulic cylinder 9 expands and contracts, and the shifter case 18
Is rotated, and the directions of the front and rear wheels 7 and 8 are changed by a steering method according to the position of the support shaft 25a. The rotation angle of the shifter case 18 by the hydraulic cylinder 9 is detected by the angle detection sensor 17 and is fed back to the control circuit 47. The hydraulic cylinder 9 is expanded and contracted by switching an electromagnetic valve, and the solenoid of the electromagnetic valve is connected to a control circuit 47. The rotation of the steering wheel 1 is also detected by a sensor, and this sensor is also connected to the control circuit 47. Have been.

Next, the operation of the switching mechanism 22 will be described with reference to FIG.
This will be described with reference to FIGS. As shown in FIGS. 5 and 9, when the vehicle travels on a general road, the steering is performed only on the front wheels. In this case, the changeover switch 48 provided in the driver's seat
To front wheel steering. At this time, the angle detection sensor 1
If the value of 7 indicates that the steering wheel 1 is not in the straight traveling direction, the hydraulic cylinder 9 is driven to direct it in the straight traveling direction. Then, the motor 6 is driven to drive the rack 13
, And the support shaft 25 a, which is a connection portion with the rear relay rod 24, is driven so as to be located coaxially with the rotation fulcrum shaft 36 of the shifter case 18.

Then, as shown in FIG. 6, the shifter case 18 rotates left and right with the turning operation of the steering wheel 1. At this time, the front relay rod 23 is displaced in the front-rear direction, and the front wheel 7 is turned in the left-right direction. On the other hand, the front end of the rear relay rod 24 only rotates and does not deviate in the front-rear direction, so that the rear wheel 8 maintains a straight state. FIG. 6
Indicates a state of turning left.

Next, when the vehicle travels in an orchard or the like for pest control or the like while keeping a small turn, the changeover switch 48 is switched to reverse phase steering and the amount of deviation is set by the setting device 49. 6 is driven, the rack 13 is slid, and the support shaft 25a of the connecting portion with the rear relay rod 24 is driven.
Is detected by the rack position detection sensor 11, and when it is slid to the set position, the drive of the motor 6 is stopped. At this time, the support shaft 25a is located to the right of the rotation support shaft 36 of the shifter case 18.

When the steering wheel 1 is turned, for example, to the left in this state, as shown in FIG.
Is extended, the shifter case 18 is rotated clockwise about the rotation fulcrum shaft 36, and this rotation causes the front relay rod 23 to rotate.
The front wheel 7 is turned to the left via the front bell crank 2, the left and right tie rods 4.4, and the front knuckle arms 33, 33. On the other hand, the rear relay rod 24 is pushed rearward, and the rear wheel 8 is rotated rightward via the rear bell crank 3, the left and right tie rods 5.5, and the rear knuckle arms 34. As a result, the traveling vehicle is in anti-phase steering, and the turning radius can be reduced.
Similarly, when the steering wheel 1 is turned to the right, anti-phase steering is performed. Note that the steering angle of the rear wheel 8 at the same rotation angle of the shifter case 18 is the rotation fulcrum axis 3 of the support shaft 25a.
Since the larger the distance from 6 is, the larger the distance, the larger the distance from (6), the finer the adjustment can be made.

In order to escape from the edge of a cliff or a ditch, etc., in order to avoid collision of the vehicle body with the cliff or departure from the ditch, the changeover switch 48 is switched to in-phase steering, and the amount of deviation is also set by the setting device. 4
9, the motor 6 is driven in the opposite direction to slide the rack 13, and the position of the support shaft 25 a of the connecting portion with the rear relay rod 24 is set to the rack position detecting sensor 1.
When it is detected by 1 and slid to the set position, the drive of the motor 6 is stopped. At this time, the support shaft 25a is located to the left of the rotation fulcrum shaft 36 of the shifter case 18.

When the steering wheel 1 is turned, for example, to the left in this state, as shown in FIG.
Is extended, the shifter case 18 is rotated clockwise about the rotation fulcrum shaft 36, and this rotation causes the front relay rod 23 to rotate.
The front wheel 7 is turned to the left via the front bell crank 2, the left and right tie rods 4.4, and the front knuckle arms 33, 33. Then, the rear relay rod 24 is pulled forward, and the rear wheel 8 is rotated leftward via the rear bell crank 3, the left and right tie rods 5.5, and the rear knuckle arms 34. As a result, the traveling vehicle is in-phase steering and can move in parallel.
When the steering wheel 1 is turned to the right, the same phase steering is performed. Also in this case, similarly to the reverse phase steering, the steering angle of the rear wheel 8 at the same rotation angle of the shifter case 18 increases as the distance of the support shaft 25a from the rotation fulcrum shaft 36 increases.

When the front wheel steering, the anti-phase steering, and the in-phase steering are changed as described above, first, the shifter case 18 is once set to the neutral position, that is, as shown in FIG. As a state toward
The rack 13 is slid in the shifter case 18 so as to be changed.

That is, at a position other than the straight traveling position, the rack 13
, The rear relay rod 24 is pushed and pulled, so that the rear wheel 8 also rotates simultaneously.
To rotate the rear wheel 8 supporting the heavy body, the pinion 12
Requires a large power, and the motor 6 has a large weight and a large outer diameter.
However, in the straight traveling position (neutral position), as shown in FIG. 5, the shifter case 18 coincides with an arc centered on the rear pivot 24a of the rear relay rod 24.
Can change the steering system quickly and reliably even with a small output motor even with a small output. Further, since excessive force does not act on the shifter case 18, the occurrence of troubles related to the conversion mechanism 22 during traveling can be prevented. You can do it. Then, the position of the shifter case 18 is
When it is at a position other than the neutral position, the hydraulic cylinder 9 is driven to return to the neutral position, and then the control circuit 47 controls the motor 6 according to the values of the changeover switch 48 and the setting device 49 to drive the motor 6. ing.

As described above, the sensor 11 for detecting the position of the shifter case 18 and the position of the rack 13 which is a moving body,
17, the rack 13 can be driven by the motor 6 as an actuator, the sensors 11, 17 and the motor 6 are connected to a control circuit 47, and the shifter case 18 is controlled to move the rack 13 only in the straight-ahead position. Therefore, it is possible to quickly return the shifter case 18 to the neutral position from any steering state and to switch the steering method, and to accidentally switch the steering method at a position other than the neutral state, and damage the motor and gears. Can be prevented.

With the above configuration, it is possible to switch between reverse-phase steering, in-phase steering, and front two-wheel steering with only a simple operation. Since the support shaft 23a and the support shaft 25a, which are the respective connecting portions to the mechanisms 20, 21, are located at substantially the same height as the shifter case 18 provided substantially horizontally, there is almost no torsion on each shaft, and the shaft is light. The switching of the steering system can be reliably performed by the operation, and the operation accuracy and the component life can be improved. Furthermore, the normal width between the wheels is sufficient for the operation of the shifter case 18, and there is no danger of increasing the vehicle height and increasing the size of the vehicle body.

[0028]

As described above, the present invention has the following advantages. That is, in claim 1, the shifter case is disposed substantially horizontally between the front wheel and the rear wheel, and is supported on the vehicle body frame so as to be rotatable around a rotation fulcrum provided at the center in the left and right direction of the shifter case. Connecting the shifter case to a steering relay and a front relay rod which is linked to a front steering mechanism of a front wheel, and fitting a movable body whose position can be changed into the shifter case, and connecting the movable body to a rear steering mechanism of a rear wheel. Because the front relay rod and the rear relay rod are connected to the rear relay rod, which is linked to the shifter case, the front relay rod and the rear relay rod can be appropriately displaced in the front-rear direction with respect to the rotation of the shifter case. Switching to steering, in-phase four-wheel steering, and anti-phase four-wheel steering can be realized, and the most efficient and stable driving can be selected by selecting the steering method according to the work or traveling site. It can become. In addition, the shifter case is configured to be long in the horizontal direction, so that the traveling vehicle can have a low center of gravity without lowering the ground height.

According to a second aspect of the present invention, the shifter case and the moving body are formed in an arc shape centering on a rear pivot shaft of the rear relay rod when the steering operating tool is in the straight traveling position. Since the position of the body can be changed with a small force, it is possible to quickly switch the steering method even with a small output motor.

According to a third aspect of the present invention, an actuator is connected to the movable body so that the movable body can move and the position of the movable body can be arbitrarily changed. The change rate of the steering angle of the wheel can be changed, and the degree of small turning can be finely adjusted according to the situation.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view of a traveling vehicle according to the present invention.

FIG. 2 is a partial plan sectional view of the same.

FIG. 3 is an enlarged plan sectional view of the switching mechanism of the present invention.

FIG. 4 is an enlarged side sectional view of the same.

FIG. 5 is an explanatory diagram of a positional relationship of each steering element during straight running.

FIG. 6 is an explanatory diagram of a positional relationship between respective steering elements during front two-wheel steering.

FIG. 7 is an explanatory diagram of the positional relationship between the steering elements during antiphase steering.

FIG. 8 is an explanatory diagram of a positional relationship of each steering element during the same phase steering.

FIG. 9 is a control block diagram of a shifter case rotation angle and a rack position.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steering operation tool 6 Actuator 7 Front wheel 8 Rear wheel 11, 17 Sensor 13 Moving body 16 Body frame 18 Shifter case 20 Front steering mechanism 21 Rear steering mechanism 23 Front relay rod 24 Rear relay rod 24a Rear pivot 36 Rotation fulcrum 47 Control circuit

Claims (3)

[Claims] 1. A shifter case is disposed substantially horizontally between a front wheel and a rear wheel, and is supported on a vehicle body frame so as to be rotatable around a rotation fulcrum provided at the center in the left and right direction of the shifter case. The case is connected to a steering relay and a front relay rod linked to the front steering mechanism of the front wheels, and a movable body whose position is changeable is fitted into the shifter case, and the movable body is linked to the rear steering mechanism of the rear wheels. A steering device for a traveling vehicle, wherein the steering device is connected to a rear relay rod. 2. The traveling vehicle according to claim 1, wherein the shifter case and the movable body have an arc shape centered on a rear pivot shaft of the rear relay rod when the steering operation tool is in a straight traveling position. Steering device. 3. The steering apparatus for a traveling vehicle according to claim 1, wherein an actuator is connected to the moving body so as to be movable, and the position of the moving body can be arbitrarily changed.