JPS61257362A - Control device for tractor - Google Patents

Abstract

PURPOSE:To lighten the steering operation of a tractor and to enhance the rectilinear advance capability of the same, by providing, in the steering mechanism of the tractor, a power steering unit for assisting a steering force in accordance with the turning manipulation of a steering wheel. CONSTITUTION:A power steering unit 4 is disposed in the steering mechanism for steered wheels 2. When a steering wheel which is not shown is turned in either right or left direction, a valve cylinder which is fitted therein with a valve shaft 22 and which is also not shown is rotated. Therefore, the valve is changed over to feed hydraulic oil into a hydraulic cylinder 40 so that the steered wheels 2 are steered in the direction equal to the manipulating direction of the steering wheel is made to be light. Further, during rectilinear running of the vehicle since no manipulation is made to the steering wheel, the valve cylinder will not rotate. Accordingly, the valve is maintained to be closed. Thereby, even if the steered wheel 2 has a tendency to be turned to the left or right due to concavities and convexities in a road surface, the rectilinear running condition may be maintained.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a tractor steering device.

Conventional power steering is located between a steering wheel and a steering wheel in order to increase the operating force of the steering wheel, and is always in operation regardless of whether the vehicle is turning or traveling straight.

Problems to be solved by the invention ゛When working with a tractor, the rolling of the front and rear wheels is significant due to the unevenness of the soil surface or plowing platform, and if the operating force of the steering wheel is too light, the tractor may The straightness of the vehicle is often unstable.

On the other hand, when turning in the traveling direction, the operating resistance is large and the turning operation is not easy.

Means for Solving the Problems The present invention provides an operating mechanism (3) for a steering wheel (2) operated by a steering handle (1).
) A tractor control device is provided with a power steering (4) which adds the operating force of the steering wheel (2) by turning operation of the steering wheel (1) and does not apply the force in the straight operation range of the steering wheel (1).

Effect of the Invention When the tractor is running to perform work, the steering wheels (
The tractor is steered in the direction of 2) to move the tractor in a straight line or turn. However, when this steering wheel (1) is operated to the left or right, the power steering (4) is immediately activated in conjunction with this. Working steering wheels (2)
In order to assist the driver in the direction of the turn, the operating force of the control handle (1) is lightened, and the turning operation of the control knob (1) is possible. When the steering wheel (2) is kept in a straight-ahead position without causing the steering wheel to move forward, the force of the power steering (4) is cut off, so the resistance to the operation of the steering wheel (1) by the operator is large, and the steering wheel (2) is The handle (1) is difficult to move.

Effects of the invention When turning the control handle (1) in this way,
The power steering wheel (4) works and the steering wheel (2) can be lightly steered, but the power steering wheel (4) does not work when driving straight ahead, so the steering wheel (1) cannot be rotated. Therefore, it is possible to easily maintain the straight running of the tractor. Moreover, since switching between activation and deactivation of the power steering (4) is automatically performed by the rotation angle of the steering wheel (1), no special switching operation is required, and the operation can be easily performed. It can be done easily.

Embodiment In the example shown in FIG.
)(6). A prime mover (7) and a control handle (1) are installed on the top, and a driver's seat (8) is installed behind the control handle (1).This tractor can also be connected to various working devices. However, in the example shown, the car body (5)
The lifting cylinder (9) and piston (10) are attached to the rear of the
) is provided with an elevating link (11) that is hydraulically moved up and down, and a seedling tank (12) is provided at the rear end of this elevating link (11).
), a seedling planting device (13), an auxiliary seedling mounting stand (14), a seedling planting device (16), and the like.

The steered wheel (2) connects this axle (17) to a vertical support shaft (
18) so that it can be steered and rotated freely around this support shaft (
an axle shaft (17) which is rotatable relative to the axle housing (13);
8) An operating mechanism (3) is constructed by connecting an arm (23) rotatable around a valve shaft (22) at the center with a rod (24).

For power steering (4), valve shaft (22)
A valve cylinder (20) is rotatably fitted on the outer periphery of the valve cylinder (24), and a gear (25) is provided in a part of the valve cylinder (24).
It meshes with a gear (2B) rotated by the control handle (1). Further, a pin (27) is provided at the upper end of the valve shaft (22) to protrude toward the valve cylinder (24).
27) is fitted into a long hole (28) provided in the valve cylinder (24) to provide play between the rotation of the valve cylinder (24) and the rotation of the valve shaft (22).

At the outer periphery of the valve shaft (22), at the fitting part with the valve tube (24), there is a valve chamber (2) shaped like a notch in the cylindrical surface.
9) (30) (31) (32) (33
), and a communication hole (30 is provided between the valve chambers (29) and (32), and a communication hole (30) is provided between the valve chambers (3G) and (3G).
A communication hole (35) is provided between the
The valve cylinder (24) also has an inlet (37) communicating with the hydraulic pump (3B), an outlet (3B) (39), and a communication port (39) communicating with both ends of the hydraulic cylinder (40).
41) (42) is provided. This hydraulic cylinder (40) is attached to a part of the tractor body (5), and this piston (43) is connected to a part of the arm (23). Moreover, the hydraulic cylinder (40) and the communication port (41)
(42) is provided with a switching valve (44) that can communicate or cut off the two hydraulic circuits,
It is configured to be remotely controlled using a wire (45).

The wire (45) of this switching valve (44) may be configured to be switched by an operating lever near the cockpit (8), and the piston (10) of the lifting cylinder (9)
), and in conjunction with the operation of the control lever (48) in the cockpit CB)a, the power transmission clutch of the seedling planting device (IB) is disengaged with this control lever (48), and at the same time, the lifting cylinder ( The piston (10) of 9) can be extended to raise this seedling planting device (IB), and by the extension of this piston (10), the switching valve (44) is connected via the wire (45).
) may be set in a closed state so that the power steering can operate, and furthermore, the switching valve (44) may be linked with the travel gear shift lever so that the power steering does not operate when the tractor is running on the road.

The seedling planting device (IB) is provided with a seedling planting device (13) that separates and inserts seedlings as the seedlings are fed out of the seedling tank (12) at the lower end of a seedling tank (12) that slopes downward toward the rear lower part. is,
The reciprocating movement of the seedling tank (12) in the left and right lateral directions, the seedling delivery mechanism (47), the seedling planting device (13), etc. are interlocked by a power output shaft from the rear side of the tractor. . Also, the auxiliary seedling stand (14) on the top of the seedling tank (12) has a four-point link mechanism (48), and what is this side of the seedling tank (12)? Since it can be rotated back and forth in parallel, in the forward rotated position, the rear end of this auxiliary seedling stand (14) approaches the surface of the seedling tank (12), and the seedling stand (1
By opening the on-off valve (49) provided at the rear end of the seedling tank 0, the seedlings on the auxiliary seedling platform (14) can be supplied to the seedling tank (12). (50) is each on-off valve (1
9) This is an operating wire that opens and closes the opening/closing operation.

When holding the steering wheel (1) in the straight-ahead position,
With the relationship between the valve shaft (22) and the valve cylinder (24) as shown in Figure 4, the inlet (37) is closed and the communication port (4
1) is closed, and the communication port (42) is connected to the valve chamber (28).
Even if the valve chamber (28) and the communication hole (3
4), there is no flow of pressure oil into or out of the valve chamber (32), etc., and the switching valve (44) is closed, so the flow of pressure oil in the cylinder (40) is not possible. Therefore, even if the steered wheels (2) are steered in the straight-ahead direction and are attempted to be rotated left and right about the support shaft (18), the wheels (2) will not sway horizontally and will not move straight. Can be maintained.

When rotating the control handle (1) to the right to turn the running force direction to the right, the valve cylinder (24) is rotated within the range of the elongated hole (28) in the direction of the arrow (A). The inlet (37) communicates with the valve chamber (33), and pressurized oil is pressurized into the cylinder (40) through the communication hole (35), the valve chamber (30), the communication port (41), etc. ) is the valve chamber (2
9) The piston (43) is actuated in the direction (b) of retracting into the cylinder (40) because it communicates with the outlet (38) through the communication hole (34) and the valve chamber (32);
By rotating the arm (23), the steering wheels (2) (2) are rotated to the right (c), so that the right-hand operating force of the steering handle (1) is lightened.

Conversely, when turning the control handle (1) to the left, the valve cylinder (20) is turned in the opposite direction of the arrow (A), so that the inlet (37) is connected to the valve chamber (29). The communication port (41) communicates with the valve chamber (31) and the outlet (38), and communicates with the valve chamber (28), the communication port (42) and the cylinder (40), and the communication port (41) communicates with the valve chamber (31) and the outlet (38). The piston (43) is pushed out in the opposite direction of the arrow (b),
By rotating the steering wheel (2) in the opposite direction of the arrow (c), that is, to the left, the vehicle can turn left. Therefore, the steering handle (1)
The left operating force becomes lighter.

Operate the operating lever (4B) to raise and lower the cylinder (9).
When the piston (10) is extended, the elevating link (11)
The seedling planting device (1B) is raised from the seedling-planting position to the non-seedling position, but at this time, the wire (45)
When is pulled and the switching valve (44) is communicated, the piston (43) is not operated as described above. In other words, during the right turning operation, the pressure oil in the communication port (41) is not connected to the switching valve. (
44) to the communication port (42), and during left turning operation, the pressure oil in the communication port (42) escapes from the communication port (41) via the switching valve (44).
0) Pressure oil is not pumped into the inside.

When the valve shaft (22) is not rotated by the piston (43) even if the valve cylinder (24) is rotated, as in the case of a failure of the hydraulic circuit, the control handle may be moved beyond the play angle of the elongated hole (28). (1) forcibly rotates the steering wheel (2) until the power steering (4) is disabled.
) can be steered.

[Brief explanation of drawings]

The figures show one embodiment of the present invention; FIG. 1 is a partial side sectional view, FIG. 2 is a partial plan view, FIG. 3 is a partial enlarged plan view, and FIG. 4 is a partial side sectional view. FIG. 5 is a partial side view, FIG. 6 is a side view, and FIG. 7 is a partial plan view. In the figure, the symbol (1) indicates the steering wheel, (2) the steering wheel, (3) the operating mechanism, and (4) the power steering.

Claims (1)

[Claims] By turning the steering wheel (1), the operating force of the steering wheel (2) is applied to the operating mechanism (3) of the steering wheel (2) operated by the steering wheel (1). A tractor control device that is equipped with a power steering (4) that does not provide assistance in the straight-line operating range.