JP3176237B2 - Work vehicle steering system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering device for a working vehicle such as a combine or a transport vehicle, and more particularly to a technique for enabling a turning radius to be set steplessly.

[0002]

2. Description of the Related Art For example, there are a transport vehicle disclosed in Japanese Utility Model Laid-Open No. Sho 61-152527 and a combine disclosed in Japanese Patent Application Laid-Open No. 6-99842. In these work vehicles, a pair of left and right side clutches and a pair of left and right side brakes,
And a forward / reverse rotation mechanism, so that one of the traveling devices is freely rotated, a brake is turned to stop one traveling device (a pivot turn), and one traveling device is different from the other traveling device. It was configured so that each of the turning forms of the sharp turning (super turning) driven in the opposite direction could appear.

[0003]

For example, in the technique disclosed in the above-mentioned publication, the above-mentioned turning modes are sequentially controlled by a single operating lever by devising a mechanism such as a side clutch or a side brake in cooperation. Although it is configured to be able to appear well, the turning radius is 3
Only three types of turning modes are possible, and there is room for improvement in that the setting of the turning radius is limited. An object of the present invention is to improve the steering operation performance by freely setting the turning radius.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a planetary speed change mechanism comprising a sun gear, a planetary gear, and an annular gear meshing with the planetary gear. a pair so as to act for each, traveling as transmission system for the planetary gear mechanism, is interposed a power forward direction and the reverse direction and to steplessly by HST capable of transmitting across from the engine A hydraulic input system consisting of a primary input system for speed change, a variable pump and a hydraulic motor
And a secondary input system for steering via a steering transmission mechanism configured to be capable of continuously variable transmission using a step transmission.
A sub-transmission is disposed in the primary input line of the two transmission systems, and two of the sun gear, the planetary gear, and the ring gear are output to the drive axle. Gears and input receiving gears from the primary input series, and the remaining one gear is provided so that power from the secondary input series is transmitted. The steering transmission mechanism is continuously variable.
Left and right by the output from the hydraulic motor
The gears are configured to be able to be simultaneously driven in a state where their rotation directions are opposite to each other, and to be simultaneously stopped, and furthermore, to be able to switch the rotation direction of the hydraulic motor in the simultaneous drive state between forward and reverse , and In the neutral state to stop the rotation of the hydraulic motor
Provided with a switchable directional control valve, wherein in association with the forward-reverse switching of the primary input sequence of HST two
Switch to change the rotation direction of the hydraulic motor of the next input series
Switching the forward / backward position of the valve and the oil of the primary input system
The switching valve is set to the middle position in conjunction with the neutral operation of the pressure-type continuously variable transmission.
A control device for switching operation to a standing position is provided.

[0005]

According to the above construction, the details of the embodiment will be described. However, when the left and right gears are simultaneously stopped by the function of the steering transmission mechanism, the left and right planetary transmission mechanisms are aligned in the same rotational state. Then, the left and right drive axles are driven at the same speed to each other, and a straight traveling state appears. When the left and right gears are simultaneously driven in a state where their rotation directions are opposite to each other, the output rotation of one of the planetary transmission mechanisms becomes faster and the other planetary transmission mechanism as compared with the above-described simultaneous drive state. The output rotation of the speed change mechanism acts to be slow. Therefore, by adjusting the simultaneous driving speed in a state where the rotation directions are opposite to each other, the magnitude of the speed difference between the left and right traveling devices can be set in a stepless manner.

That is, in the case of a combine, for example, a super pivot turning in which the left and right traveling devices are driven in opposite directions, a pivot turning in which one traveling device stops, and one traveling device is in the same direction as the other traveling device. Each turning form such as a slow turning driven gentle turning is made possible, and a state having a turning radius between these turning forms can be shown in a stepless manner. In addition, since the fuselage performs not only forward movement but also reverse movement, it has a switching mechanism that can switch the rotation direction in simultaneous driving in the forward and reverse directions, so that the turning radius can be selected steplessly in both forward and backward movements. Can be performed.

[0007]

As a result, the speed difference between the left and right traveling devices can be arbitrarily determined by adopting a pair of planetary transmission mechanisms and contradicting the rotation of one of the three element gears constituting the planetary transmission mechanism. This makes it possible to provide a steering device with excellent steering operability, which can adjust and set the turning radius steplessly regardless of whether the vehicle is moving forward or backward.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings for a combine as an example of a work vehicle. FIG.
, A combiner 1 is a harvesting unit, 2 is a steering unit, 3 is a threshing device, 4 is a feed chain, 5 is a crawler traveling device, and M is a traveling mission. FIG. 1 shows a diagram of the traveling mission M, in which 6 is an HST receiving engine power,
7 is a two-stage auxiliary transmission mechanism, 8L and 8R are drive axles, 9
Denotes a planetary transmission mechanism, and 10 denotes a steering transmission mechanism.

A planetary speed change mechanism 9 is provided for each drive axle 8L, 8R, and a sun gear 12 mounted on a relay shaft 11 receiving the power of the auxiliary speed change mechanism 7, and a cylindrical shaft 13 which meshes with the drive axles 8L, 8R. , And an annular gear 15 that is inscribed in the planetary gear.

The steering transmission mechanism 10 includes an input shaft 6 of the HST 6.
a variable pump 16 driven by the
And a hydraulic motor 17 driven by
A first shaft 18 and a second shaft 19 that are in gear engagement with the output shaft 17a. The first shaft 18 is externally engaged with the annular gear 15 of the left planetary transmission mechanism 9, and the second shaft 19 is internally engaged with the annular gear 15 of the right planetary transmission mechanism 9. When rotated, the left and right annular gears 15 are driven to rotate in opposite directions.

Further, a steering device A is provided which can change and adjust the turning radius of the machine body in a stepless manner by changing the swash plate angle of the variable pump 16. That is, the swash plate 16
a, an operation cylinder 20 for oscillating a, a three-position switching type electromagnetic control valve 21, a steering lever 22 for switching the control valve 21, and an interlocking operation of the steering lever 22 for tilting operation. The steering device A is composed of the variable aperture 23 and the like.

The operation cylinder 20 includes two return springs 2.
The control valve is configured as a double-acting type that returns to neutral at 4, 24.
A variable throttle 23 is connected to a pair of oil passages 25, 25. The steering lever 22 is urged to return to the vertically standing neutral position. In this state, the control valve 21 is also in the neutral position, and the variable throttle 23 is linked so that the throttle becomes the slowest.

When the steering lever 22 is tilted to the right or left, the control valve 21 immediately switches to the right steering position or the left steering position, and the variable throttle 23 adjusts the throttle in proportion to the amount of tilt of the lever. The slider 26a, which can be slid only by the rail support, and the interlocking means 26 such as a wire or a rod, are linked so that the steering lever 22 can be tilted in any direction from the neutral position to the left or right. The structure is operated so that the aperture is tight. The steering lever 2 is controlled by a potentiometer 27 described later.
2, the variable aperture 23 may be adjusted and set by a servomotor driven based on the detected information.

The operation of the steering device A will be described.
First, when the steering lever 22 is in the neutral position, the swash plate 16a
Is zero, the hydraulic motor 17 does not rotate and the stopped state is maintained, and the left and right planetary transmission mechanisms 9
Are in exactly the same shifting state and the left and right drive axles 8L, 8R
Is driven at a constant speed, and the aircraft travels straight. The steering lever 22 and the control valve 21 are connected via a potentiometer 27 and a control device 28, and the control valve 21 is switched as the steering lever 22 is tilted.

Next, when the steering lever 22 is tilted to the right, the control valve 21 is switched to the right steering position, and one of the oil passages 2 is moved.
5, the hydraulic oil is supplied to the right hydraulic chamber 20R, and the left hydraulic chamber 20L is drained through the other oil passage 25. At this time, the variable throttle 23 is in proportion to the lever tilt amount. As a result, the piston rod 20a of the operation cylinder 20 is extended and contracted by an amount corresponding to the amount of tilting operation of the operation lever 22. In other words, if the hydraulic motor 17 rotates with an angle to the swash plate 16a, the actions of the left and right planetary transmission mechanisms 9, 9 are reversed, and the left and right steering devices 5,
5 causes a relative speed difference, and the aircraft turns rightward.

Then, as the amount of tilt of the steering lever 22 increases, the relative speed difference between the left and right steering devices 5 and 5 increases, the turning radius decreases, and the right crawler steering device 5 increases.
Can be turned to a super pivot turn depending on how the gear ratio of the planetary transmission mechanism 9 is set. That is, by increasing the pressure in the oil passage 25 in proportion to the amount of tilt of the steering lever 22, it becomes possible to reduce the turning radius in proportion to the amount of tilt of the steering lever 22. The same is true for the times.

As shown in FIG. 1, there is provided a switching mechanism B for switching the steering transmission mechanism 10 between forward and reverse in accordance with switching between forward and backward movement. That is, a three-position switching valve 29 is provided in a pair of oil passages connecting the variable pump 16 and the hydraulic motor 17, and the switching valve 29 and the shift lever 30 of the HST 6 are linked to each other, and a potentiometer 31 for detecting the operating position. When the shift lever 30 is operated forward, the switch valve 29 is also operated to the forward position, and when the shift lever 30 is operated backward, the switch valve 29 is also operated to the reverse position.
When 0 is neutralized, the switching valve 29 is also operated to the neutral position.

For example, the shift lever 30 and the steering lever 22
When the shift lever 30 is operated backward in order to shift to the backward left turn while the forward left turn state is displayed, the left and right planetary speed change mechanisms 9 and However, if the steering gear 10 is reversed in accordance with the forward / reverse operation as in the present application, only the forward / backward switching operation is performed. However, the turning direction is maintained as it is.

In the above-described embodiment, the sun gear 12 and the planetary gear 14 are used as a gear for taking out the output to the drive axles 8R and 8L and a gear for receiving the input from the auxiliary transmission mechanism (corresponding to the upper transmission side) 7. The steering gear mechanism 10 is configured to be distributed and capable of independently driving the ring gear 15 for variable rotation. For example, two planetary gears 14 and a ring gear 15 are connected to the drive axles 8R and 8L. The output gear and the input gear from the auxiliary transmission mechanism 7 may be separately set so that the sun gear 12 can be independently driven by the hydraulic motor 17 for variable rotation.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a transmission system of a combine and a steering structure.

FIG. 2 is a side view of the front of the combine.

[Explanation of symbols]

 8L, 8R Drive axle 9 Planetary transmission mechanism 10 Steering transmission mechanism 12 Sun gear 14 Planetary gear 15 Ring gear B Switching mechanism

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B62D 11/00-11/24

Claims (1)

(57) [Claims] 1. A sun gear (12) and a planetary gear (14).
And an annular gear (1) inscribed and engaged with the planetary gear (14).
And 5) a pair of planetary transmission mechanisms (9), which act on each of the left and right drive axles (8L) and (8R), as a transmission system for the planetary transmission mechanism (9) to receive power from the engine. steplessly over the forward and reverse direction
A shift to the primary input sequence for the running speed gear which is interposed a hydraulic stepless transmission capable of transmitting (6), a variable pump (16) and the hydraulic stepless variable consisting a hydraulic motor (17)
And a secondary input system for steering via a steering transmission mechanism (10) configured to be capable of stepless speed change using a speed change device. A sub-transmission (7) is arranged in the series, and two (12) and (14) of the sun gear (12), the planetary gear (14), and the ring gear (15) are connected to the drive axle ( 8L) and (8R), and a gear for receiving the input from the primary input system is set separately, and the remaining one gear (15) is transmitted by the power from the secondary input system. And the steering mechanism (10) of the secondary input system is provided with a continuously variable transmission.
The output from the hydraulic motor (17) allows the left and right one gears (15), (15) to be simultaneously driven and stopped simultaneously with their rotational directions opposite to each other. The rotation direction of the hydraulic motor (17) in the simultaneous driving state can be switched between forward and reverse , and the rotation of the hydraulic motor (17) can be changed .
And a switching valve (29) that can be switched to a neutral state for stopping the hydraulic motor of the secondary input system in conjunction with the forward / backward switching of the hydraulic continuously variable transmission (6) of the primary input system. 1
7) Before and after the switching valve (29) to switch the rotation direction
Position, and the hydraulic stepless change of the primary input system
The switching valve (29) in conjunction with the neutral operation of the speed change device (6)
A steering device for a working vehicle, comprising a control device (28) for switching the position of the vehicle to a neutral position .