JPH08156821A - Steering device for working vehicle - Google Patents

Abstract

PURPOSE: To improve steering operation performance by adopting a pair of planetary transmission mechanisms and changing the rotating speed of one of three structural elements in mutually righ-and-left opposite operation so that a turning radius can be freely set. CONSTITUTION: When a steering lever 22 is in a neutral position, right and left planetary transmission mechanisms 9, 9 are at the same speed to drive right and left drive axles 8R, 8L at an equal speed for a machine to run straight. When the steering lever 22 is tilted to the right, a piston rod 20a for an operating cylinder 20 is expanded and moved equivalently to the tilting operation of the steering lever 22. That means, the right and left planetary transmission mechanisms 9, 9 are in mutually opposite operation and a relative speed difference between right and left steering devices 5, 5 occurs for the machine to be turned to the right. As the tilting of the steering lever 22 is increased, pressure in an oil passage 25 is higher and a turning radius is smaller. This applies also to left turning.

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 carrier, and more particularly to a technique for enabling a turning radius to be set continuously.

[0002]

2. Description of the Related Art For example, there are a carrier shown in Japanese Utility Model Laid-Open No. 61-152527 and a combine shown in Japanese Patent 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,
By providing the forward and reverse rotation mechanism, one of the traveling devices can freely rotate, a slow turn that stops one of the traveling devices (a pivotal turn), and one of the traveling devices can be different from the other traveling device. It was configured so that each turning form of a sudden turn (super-spinning turn) driven in the opposite direction could appear.

[0003]

SUMMARY OF THE INVENTION For example, in the technique disclosed in the latter publication, one turning lever is used to sequence the above-mentioned turning forms by devising a mechanism such as a side clutch and a side brake to operate in a linked manner. Although it is constructed so that it can appear well, the turning radius is 3
There are only three types of turning modes, 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 allowing the turning radius to be freely set.

[0004]

In order to achieve the above object, the present invention provides a planetary speed change mechanism including a sun gear, a planetary gear, and an annular gear that is inscribed in the planetary gear. Two pairs of sun gears, planetary gears, and annular gears are provided so as to act on each of them, and two of the sun gears, the planetary gears, and the annular gears are set to be divided into an output take-out gear to the drive axle and an input receiving gear from the transmission side, In addition to providing a steering speed change mechanism capable of independently variably rotating the remaining one gear, the steering speed change mechanism is
It is characterized in that the remaining left and right gears can be simultaneously driven and simultaneously stopped in a state where their rotation directions are opposite to each other.

[0005]

According to the above-mentioned structure, as will be described in detail in the embodiment, when the remaining 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 rotation state. , The left and right drive axles are driven at the same speed, so that a straight traveling state appears. When the remaining left and right gears are simultaneously driven in a state in which their rotation directions are opposite to each other, the output rotation of one planetary speed change mechanism becomes faster than that in the simultaneous drive state, and the other planetary gear shifts. The output rotation of the speed change mechanism acts so as to be slow. Therefore, by adjusting the simultaneous driving speeds 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 steplessly. In other words, taking a combine as an example,
Various turning modes are possible, such as super-turning turning that drives the left and right running devices in opposite directions, turning turning in which the running device on one side stops, and gentle turning in which the running device on one side is driven slowly in the same direction as the other running device. As a result, the state of the turning radius between each of the turning forms can be exhibited steplessly.

[0006]

As a result, the speed difference between the left and right traveling devices can be arbitrarily set by adopting a pair of planetary speed change mechanisms and contrariwise shifting one rotation of one of the three constituent gears of the left and right gears. Thus, it is possible to provide a steering device with excellent steering operability that allows the turning radius to be adjusted and set steplessly.

[0007]

Embodiments of the present invention will be described below with reference to the drawings of a combine, which is an example of a work vehicle. Figure 2
A combine is shown in FIG. 1, 1 is a mowing unit, 2 is a control unit, 3 is a threshing device, 4 is a feed chain, 5 is a crawler traveling device, and M is a traveling mission. A diagram of the traveling mission M is shown in FIG. 1, and 6 is an HST that receives engine power,
7 is a sub-transmission mechanism with two high and low stages, 8L and 8R are drive axles, and 9
Is a planetary speed change mechanism, and 10 is a steering speed change mechanism.

The planetary speed change mechanism 9 is provided for each of the drive axles 8L and 8R, and has a sun gear 12 attached to a relay shaft 11 that receives the power of the auxiliary speed change mechanism 7 and a cylindrical shaft 13 that meshes with the drive axles 8L and 8R. And a ring gear 15 that is inscribed in the planet gear.

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

Further, there is provided a steering device A capable of continuously changing and adjusting the turning radius of the machine body by changing the swash plate angle of the variable pump 16. That is, the swash plate 16
An operating cylinder 20 for swinging a, a three-position switching type electromagnetic control valve 21, a steering lever 22 for switching the control valve 21, and a tilting operation of the steering lever 22 are operated. The steering device A is composed of the variable diaphragm 23 and the like.

The operating cylinder 20 includes two return springs 2.
It is a double-acting type that returns to neutral with 4, 24, and the control valve 2
The variable throttle 23 is connected across the pair of oil passages 25 and 25. The steering lever 22 is urged to return to a vertically erected neutral position. In this state, the control valve 21 is also in the neutral position, and the throttle of the variable throttle 23 is linked so as to be the loosest.

When the steering lever 22 is tilted right or left, the control valve 21 is immediately switched to the right steering position or the left steering position, and the variable throttle 23 is throttled in proportion to the lever tilt amount. The slider 26a, which is slidable only by rail support, and the interlocking means 26, such as a wire or a rod, are linked to each other so that the steering lever 22 can be tilted to the left or right from the neutral position.
It is a structure that is operated so that the diaphragm of the lens is tight. or,
A structure in which the position of the steering lever 22 is detected by a potentiometer 27, which will be described later, and the variable diaphragm 23 is adjusted and set by a servomotor driven based on the detected information may be used.

The operation of the steering device A will be described below.
First, when the steering lever 22 is in the neutral position, the swash plate 16a
Angle becomes zero, the hydraulic motor 17 does not rotate and the stopped state is maintained, and the left and right planetary transmission mechanisms 9, 9
Are in the same gear shifting state, and the left and right drive axles 8L, 8R
Is driven at a constant speed, and the aircraft runs 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 tilts.

Next, when the steering lever 22 is tilted to the right, the control valve 21 is switched to the right steering position, and the one oil passage 2 is moved.
The pressure oil is supplied to the right hydraulic chamber 20R via 5 and the left hydraulic chamber 20L is drained via the other oil passage 25. At that time, the variable throttle 23 is proportional to the lever tilt amount. Since the piston rod 20a of the operation cylinder 20 is expanded and contracted, the piston rod 20a of the operation cylinder 20 expands and contracts by an amount corresponding to the tilting operation amount of the operation lever 22. That is, when the hydraulic motor 17 rotates with an angle on 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 are operated.
Due to the relative speed difference at 5, the aircraft turns right.

As the tilting amount of the steering lever 22 increases, the relative speed difference between the left and right steering devices 5 and 5 also increases and the turning radius decreases, and the right crawler steering device 5 increases.
It is also possible to make the super turning turn appear when the turning turn is stopped or depending on how the gear ratio of the planetary speed change mechanism 9 is set. That is, since the pressure in the oil passage 25 increases in proportion to the tilt amount of the steering lever 22, it becomes possible to reduce the turning radius in proportion to the tilt amount of the steering lever 22. The same is true for the case of times.

[Other Embodiments] The steering device A may be constructed by adopting an electric motor instead of the hydraulic pump 17 and increasing the rotational speed of the electric motor in proportion to the tilt of the steering lever 22. . In the embodiment described above, the sun gear 12 and the planetary gear 14 are gears for taking out the output to the drive axles 8R, 8L, and the auxiliary transmission mechanism (corresponding to the transmission side).
A steering transmission mechanism 1 which is set to be distributed to an input receiving gear from 7 and is capable of independently rotating the annular gear 15 in a variable rotation manner.
Although it is configured as 0, for example, two sets of the planetary gear 14 and the annular gear 15 are set by dividing them into a gear for taking out an output to the drive axles 8R and 8L and a gear for receiving an input from the auxiliary transmission mechanism 7. However, the sun gear 12 may be configured to be independently variable-driving by the hydraulic motor 17.

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 drawings]

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

FIG. 2 is a side view of the combine.

[Explanation of symbols]

 8L, 8R drive axle 9 planetary speed change mechanism 10 steering speed change mechanism 12 sun gear 14 planetary gear 15 annular gear

Claims (1)

[Claims] 1. A sun gear (12) and a planetary gear (14).
And an annular gear (1) that is inscribed in the planetary gear (14).
5) and a pair of planetary speed change mechanisms (9) each of which acts on each of the left and right drive axles (8L), (8R), and the sun gear (12), the planetary gear (14), and the annular gear. Two gears (14) and (12) of (15)
The output gears for the drive axles (8L) and (8R) and the gears for receiving the input from the transmission side are set separately, and the remaining one gear (15) can be independently rotatably driven. A steering gear mechanism (10) is provided, and the steering gear mechanism (10) includes the remaining left and right gears (1).
A steering apparatus for a work vehicle configured such that 5) and (15) can be simultaneously driven and simultaneously stopped in a state where these rotation directions are opposite to each other.