JPH081175Y2 - Agricultural tractor steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a steering device for an agricultural tractor, and more particularly to a steering wheel that reliably detects the steering angle of the steering wheel when the vehicle is traveling. The present invention relates to a steering device for an agricultural tractor capable of increasing the number of rotations of the vehicle and performing safe and smooth operation of the machine body.

[Conventional technology]

2. Description of the Related Art Conventionally, there has been proposed a steering apparatus that detects the steering angle of a steering wheel when the agricultural tractor is traveling, and increases the rotation speed of the steering wheel to perform the traveling of the vehicle.

However, this is a method of detecting the amount of rotation of the steering wheel or steering shaft, or
A method of detecting the operating rotation angle of the kingpin mounted on the front axle, a method of detecting the expansion and contraction operation amount of the power steering cylinder also mounted on the front axle,
Since it is configured to detect the steering angle by controlling the increase in the number of rotations of the steered wheels, both methods require a left and right detection mechanism to detect the right and left steering states respectively. In addition to the fact that the detection mechanism cannot be constructed at low cost, the left and right steering detections are likely to vary, and adjustment work that requires advanced technology must be performed in order to maintain the detection accuracy evenly and horizontally. It had the drawback that it had to be.

[Problems to be solved by the present invention]

The present invention has been made in view of the above circumstances in order to solve the drawbacks of the related art, and its purpose is to detect the steering state of the left and right steering wheels above the front axle. Not only can the detection by the mechanism be used to eliminate variations in left and right steering detection, but the detection mechanism can be easily adjusted by switching the steering wheel acceleration control mechanism with a single operation switch. It is an object of the present invention to provide a steering device for an agricultural tractor that is capable of simplifying the detection mechanism.

[Means for solving the problem]

In order to solve the problem, the technical means adopted by the present invention is to provide knuckle arms at both ends of a front axle supported by a rocking shaft that is horizontal in the front-rear direction, and the knuckle arms correspond to the rotation of steering. A steering device for an agricultural tractor, which pivotally mounts a tie rod that swings left and right and includes a steering wheel speed-increasing control mechanism that increases the number of rotations of the steering wheel when the aircraft is traveling. A steering detection switch mechanism, which is located above the axis and detects the forward / backward movement associated with the left / right swing of the tie rod, is provided. The steering wheel acceleration control mechanism is linked to the tie rod forward / backward movement detection of the steering detection switch mechanism. It is characterized in that a single actuation switch for switching between actuation and non-actuation of is provided.

[Function of device]

Therefore, according to the present invention, since the forward / backward movement of the tie rod is detected only by the steering detection switch function provided above the swing axis of the front axle when the vehicle is traveling, it is possible to steer the vehicle in either the left or right direction. The steering detection does not vary from side to side, and even if the front axle swings, the steering detection switch mechanism provided above the swing axis is hardly affected. Then, since the single operation switch switches the steering wheel speed increasing control mechanism between the operating state and the non-operating state, the detection mechanism can be easily adjusted and the detection mechanism can be simplified.

〔Example〕

The configuration of the present invention will be described in detail with reference to one embodiment shown in the drawings.

1 to 3, reference numeral 1 denotes an agricultural tractor body, and a body frame 2 of the body 1 has a right front wheel 3a,
The left front wheel 3b, the right rear wheel 4a, and the left rear wheel 4b are pivotally supported.
A steering mechanism 5 for rotating the machine body 1 is attached to the front wheels 3a, 3b. The steering mechanism 5 is provided in a bonnet 6 and a hydraulic pump 7 mounted in a rear portion of the bonnet 6. The steering control of the left and right front wheels 3a, 3b is performed via the power steering unit 8a corresponding to the rotation of the steering wheel 8 thus generated. The pressure oil reservoir 9 is provided above the left and right rear wheels 4a and 4b.
Is provided, and the amount of oil required for hydraulic control of each part is stored. A seat 10 is formed above the pressure oil reservoir 9, and an operation panel 11 is provided in front of the seat 10. Brackets 12 and 13 are arranged on the lower surface of the machine body frame 2 so as to be spaced apart from each other in the front-rear direction.
Pivot shaft 15 and transmission shaft horizontally projecting around the center of the shaft
16 is fitted, and the front axle 14 is configured to be swingable with respect to the machine body frame 2 by a swing shaft that is horizontal in the front-rear direction. Further, at both ends of the front axle 14, kingpin cases 17 and 18 in which kingpins 17a and 18a that pivotally support the front wheels 3a and 3b are installed are rotatably mounted, respectively. A tie rod 21 is connected between the knuckle arms 19 and 20 formed in the upper part. At the bottom of the bracket 12, left and right power cylinders 22 and 23 in which cylinder ends 22a and 23a are rotatably supported by the bracket 12 are vertically movably supported along the lower surface of the front axle 14. Also, the left and right power cylinders 22,23 are installed at the bottom of the knuckle arms 19,20.
The telescopic rods 22b, 23b of the above are elastically pivotally attached, and the expansion / contraction operation of the above-mentioned telescopic rods 22b, 23b causes the kingpin cases 17, 18 to be retracted.
Is rotated to steer the left and right front wheels 3a, 3b.

The bracket 12 is located above the swing axis of the front axle 14 and, as shown in FIGS. 4 to 7, is located at the center of the bottom portion 2a of the machine body frame 2 and is a steering detection switch mechanism.
24 is installed. The steering detection switch mechanism 24 is a sliding body in which a disc-shaped detection plate 27 is pivotally supported at one end on a cylindrical body 26 that is horizontally arranged by penetrating a support plate 25 provided upright on the bottom 2a. A large diameter portion 30a in which the rod 28 is telescopically inserted and the other end of the sliding rod 28 is provided with an oil groove 29 in an extremely shallow shape, and a small diameter portion 30b are provided.
A detection slider 30 formed by integrally forming and is integrally mounted via an inclined portion 30c. Further, a stopper 31 and a return spring 32 are provided on the side of the small diameter portion 30b of the detection slider 30 and a sliding rod 2
It is inserted coaxially in 8 and the sliding rod 28 is normally attached to the body 1
It is configured to bias in the traveling direction.

Above the tubular body 26, a single actuation switch 33 for ON / OFF controlling a steering wheel speed increasing control mechanism (not shown) is provided, and an actuator 33a of the actuation switch 33 is provided on the tubular body. The actuator 33a is elastically supported so that it can be retracted and retracted, and the operation switch 33 is closed by pushing up the actuator 33a to operate the steering wheel speed increasing control mechanism. Further, the circumferential end portion 27a of the detection plate 27 pivotally supported by the sliding rod 28 is constantly urged toward the steering detection switch mechanism 24 side by the urging of the return spring 32 at the central position of the body 1. The sliding rod is moved by the forward / backward movement associated with the left / right swing of the tie rod 21.
28 is designed to slide. In addition, 34 is a tubular body 26
Is an end cap, 35 is a stopper ring fixed in the tubular body 26, and 36 is a seal cap.

In the above configuration, in the state where the steering 8 is held in the neutral position, the pressure oil from the power steering unit 8a passes through the hydraulic pump 7 and the left and right power cylinders.
Evenly fed to 22,23, the telescopic rods 22b, 23b extend the rotational movement of the kingpin cases 17, 18 attached to both ends of the front axle 14 so as to maintain the straight traveling state of the front wheels 3a, 3b. The front axle 14 is held horizontally with respect to the machine body frame 2 with the pivot shaft 15 and the transmission shaft 16 as fulcrums, and the machine body 1 goes straight. In this state, the tie rod 21 is held at the position A, and the circumferential end portion 27a of the detection plate 27 is located apart from the tie rod 21, so that the sliding rod 28 is urged by the return spring 32. Sliding to the end cap 34 side, the actuator 33a of the operation switch 33 is located in the small diameter portion 30b of the detection slider 30, the operation switch 33 is in the open state, and the steering wheel speed increasing control mechanism is not operated. The state will be maintained.

Next, when the steering 8 is rotated to rotate the machine body 1 to the right, the pressure oil corresponding to the rotation of the steering 8 is pumped from the pump 7 to the right power cylinder 22, and the right power cylinder 22 is rotated. As the telescopic rod 22b of FIG. 2 expands, pressure oil is returned from the left power cylinder 23 to the pump 7, and the telescopic rod 23b sinks into the left power cylinder 23. With the expansion and contraction operation of the expansion rods 22b, 23b,
Knuckle arm formed on the kingpin case 17,18
20 rotates to the right around the axis of the kingpins 17a, 18a, and the front wheels 3,3
Is steered to the right, and the tie rod 21 connected to the knuckle arms 19 and 20 swings to the right, and the tie rod 21 moves from point A to point B as the tie rod 21 swings to the right. To the circumferential end 27a of the detection plate 27. After that, when the tie rod 21 further moves rearward to the position C by the rotation of the steering wheel 8, the sliding rod 28 starts sliding rearward through the detection plate 27, and the actuator 33a of the operation switch 33 moves It is pushed up in the process of sliding from the small diameter portion 30b of the detection slider 30 to the large diameter portion 30a via the inclined portion 30c, the operation switch 33 is closed and the steering wheel speed increasing control mechanism is in the operating state. Is switched to. When the machine body 1 is rotated leftward, the left-right direction is reversed, and the same operation as described above is performed.

Therefore, the steering angle during the left-right steering of the front wheels 3, 3 does not fluctuate in the left-right direction due to the front-back movement detection of the tie rod 21 only by the steering detection switch mechanism 24 provided above the swing axis of the front axle 14. It can be detected, and even if the front axle 14 swings, the influence on the steering detection switch mechanism 24 provided above the swing axis can be made extremely small. The single actuation switch 33 linked to the steering detection switch mechanism 24 can promptly switch the steering wheel speed increasing control mechanism to the non-operating state, so that the aircraft 1 can travel safely and smoothly. The steering detection switch mechanism 24 as a whole can be provided with a simple structure that is easy to adjust.

[Effect of device]

In short, the present invention provides knuckle arms at both ends of a front axle supported by a swing shaft that is horizontal in the front-rear direction, and a tie rod that swings left and right in response to steering rotation is pivotally mounted on the knuckle arms. While wearing, in the steering device of the agricultural tractor, which is provided with a steering wheel speed-up control mechanism for increasing the rotation speed of the steering wheel at the time of traveling of the aircraft, located above the swing axis of the front axle, A steering detection switch mechanism is provided to detect the forward / backward movement associated with the left / right swing of the tie rod, and the steering wheel speed increase control mechanism is switched between operation and non-operation in association with the detection of the tie rod longitudinal movement of the steering detection switch mechanism. Since a single actuation switch is provided, the steering wheel left / right steering angle when the aircraft is traveling can be accurately detected by the tie rod longitudinal movement detection only by the steering detection switch mechanism provided above the swing axis of the front axle. As can be seen, it is possible to eliminate variations in left and right steering detection, and even if the front axle swings, the steering detection switch mechanism provided above the swing axis makes the effect extremely small. be able to. A single operation switch linked to the steering detection switch mechanism activates and deactivates the steering wheel speed increase control mechanism, so safe and efficient operation of the aircraft can be performed, and the detection mechanism Can be easily adjusted, the detection mechanism can be simplified, and the manufacturing cost can be kept low.

[Brief description of drawings]

The drawings show an embodiment of the steering device for an agricultural tractor according to the present invention. FIG. 1 is an overall side view of the agricultural tractor, FIG. 2 is a front view of essential parts, and FIG. 3 is a plan view of essential parts. FIG. 4 and FIG. 7 are explanatory views of the operation of the main parts. In the figure, 8 ... Steering, 14 ... Front axle, 19,20
...... Knuckle arm, 21 ...... tie rod, 24 ...... steering detection switch mechanism, 33 ...... operation switch.

Claims (1)

[Scope of utility model registration request] 1. A knuckle arm is provided at both ends of a front axle that is supported by a swing shaft that is horizontal in the front-rear direction, and a tie rod that swings left and right in response to steering rotation is pivotally attached to the knuckle arm. In a steering device for an agricultural tractor, which comprises a steering wheel speed-increasing control mechanism for increasing the number of rotations of steering wheels when the vehicle is traveling, a left and right tie rods located above the swing axis of the front axle. A steering detection switch mechanism for detecting the forward / backward movement associated with rocking is provided, and a single unit for switching the operation / non-operation of the steering wheel speed increasing control mechanism in association with the tie rod forward / backward movement detection of the steering detection switch mechanism. A steering device for an agricultural tractor, which is provided with an operation switch.