JP3054053B2 - Steering device for walking tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a walking type tractor having a mechanism for turning by a side clutch such as a binder or a walking type cultivator, and more particularly, to a steering operation for turning more lightly. Related to technology.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No. 2-286469 and Japanese Utility Model Laid-Open Publication No.
Japanese Unexamined Patent Publication (Kokai) No. 1 (Kokai) No. 1 (1999) is known, in which steering is performed by one-wheel drive turning without driving one wheel.

[0003]

The structure of the side clutch is an occlusal structure such as a ball type or dog clutch shown in FIG. 1 of the latter publication.
By displacing the clutch member holding the ball in the axial direction by the operating force of gripping the steering lever, the ball is allowed to retreat in the outer radial direction, transmission is cut off, and the steering lever is gripped. When released, the force of the return spring pushes the clutch member to forcibly push the ball in the inner diameter direction, thereby returning to the transmission state. Therefore, in such an occlusal structure, a relatively large operation force is required since a ball in a state where a drive torque is acting is required, and generally, a steering lever operation of a side clutch structure is not required. It was heavy. An object of the present invention is to provide a light steering operation by incorporating the engine speed control into the side clutch operation.

[0004]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a pair of left and right drive wheels, a pair of left and right side clutches, and a pair of steering levers capable of operating these side clutches individually. In the steering device for a walking type tractor, the side clutch is disengaged when the steering lever is squeezed, and the side clutch is engaged when the steering lever is released. And a temporary deceleration mechanism for linking each steering lever with the engine so that the engine speed is temporarily reduced while the steering lever is being gripped. . A speed control linkage mechanism that links each side clutch and each steering lever is provided so that the engine rotation speed when the steering lever is depressed is lower than the engine rotation speed when the steering lever is released. It is more convenient if it is provided, and it is more convenient if an adjusting mechanism capable of variably setting the engine speed when the steering lever is held is provided.

[0005]

[Action] Considering the steering operation of the steering lever and the operating state of the side clutch using a ball-type side clutch as an example, there is play due to play of the wire or rod at the beginning of gripping, and then the clutch member actually moves. At first, the clutch is activated. Then, in order to obtain a reliable operation in anticipation of a dimensional error, a state in which the clutch member is slightly moved even after the ball comes out is revealed by a gripping state of the steering lever. That is, in the side clutch operation using the lever, it is understood that an operation force is actually required during the gripping operation and the grip releasing operation.
According to the configuration of the first aspect, since the engine speed temporarily drops while the steering lever is being depressed, the driving torque acting on the axle when the clutch operating force is actually required is reduced. As a result, the side clutch can be switched with a lighter operating force than before.

According to the second aspect of the present invention, the speed of the drive wheels during the turning of the steering lever, that is, the turning with one side clutch disengaged, is lower than that in the two-wheel drive state (straight running state). As a result, the turning speed is further reduced, and an effect of facilitating the operation of the walking type tractor, that is, following walking with the steering wheel is added. According to the configuration of claim 3, since it is possible to select the deceleration rate of the drive wheels during turning, in a dry field where steering is easy, the speed is slightly decelerated with emphasis on efficiency, and the resistance is large and it is difficult to control the mud field. In such a case, a speed suitable for field conditions and work conditions can be obtained, for example, by greatly reducing the speed.

[0007]

As a result, in the steering apparatus according to the first aspect, the side clutch operation can be performed lightly and easily by devising the engine speed to be temporarily reduced during the gripping operation range of the steering lever. As a result, the steering operability was improved.

The steering device according to the second aspect has an advantage that the steering operation can be easily performed by the automatic turning deceleration. In the steering device according to the third aspect, the steering device according to the field and business conditions. The advantage that the deceleration rate of the turning automatic deceleration can be appropriately set is added.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a walking tractor, 1 is an engine, 2 is a pair of left and right drive wheels, 3 is a traveling mission,
Is a steering handle, and 5 is a ground work device. A pair of left and right side clutches 7, 7 are provided on a traveling axle 6 of the traveling mission 3, and steering levers 8, 8 are provided on the left and right sides of the steering handle 4, respectively. When the steering lever 8 is in the free state, the side clutch 7 is engaged, and the clutch is interlocked with the clutch wire 9 so that the side clutch is disengaged when the steering lever 8 is squeezed. The clutch 7 and the right side clutch 7 are operated by the left steering lever 8, respectively.

Next, the operation structure of the side clutches 7, 7 will be described in detail. As shown in FIG. 2, a temporary speed reduction mechanism A is provided for linking each of the steering levers 8 and 8 with the engine 1 so that the engine speed temporarily drops while the steering lever 8 is being gripped. . The temporary deceleration mechanism A includes a swinging movement caused by the gripping of the steering lever 8 and a speed control lever 11.
And an interlocking structure with the governor lever 12a of the governor 12 by the operation wire 13.

That is, the operating lever 1 of the side clutch 7
0 and a steering lever 8 are interlocked and connected by a wire 9, and a swing crank 14 which is interlocked by both operating levers 10 and 10 and a rod 15 is provided. Each rod 15, 15
Are the same parts, and the long holes 15 formed at these ends are
a and 15a are fitted and connected to a pin 14a at one end of the swing crank 14. Therefore, the swinging crank 14 swings in the direction of the arrow a regardless of which one of the left and right steering levers 8, 8 is operated. When the steering levers 8, 8 are in a free state, the pin 14a is located at the lower end or substantially lower end of each of the long holes 15a.

On the other hand, the operation wire 13 is constituted by a Bowden wire composed of an inner cable 13A and outer cables 13B1 and 13B2, and the outer cable is composed of a first outer 13B1 on the speed control lever side and a second outer 13B1 on the governor lever side. It is divided into outer 13B2. The distal end of the first outer 13B1 is received by a movable receiver 16 which can swing at a fulcrum P.
The swinging crank 14 is connected to the swinging crank 14 by a rod 17, and a temporary reduction mechanism A is configured by a structure in which the movable receiving body 16 swings with the on / off operation of the side clutch 7.

The operation of the temporary reduction mechanism A will be described. As shown in FIG. 2, the steering lever 8 is in a free state (grip released state).
, The crank pivot of the swinging crank 14 and the rod 17 with respect to a line segment connecting the swinging fulcrum Q of the swinging crank 14 and the receiving pivot point Y of the movable receiving body 16 and the rod 17. The landing point X has a positional relationship shifted upward in the figure. Here, for example, when the right steering lever 8 starts to be gripped, the left operating lever 10 swings in the direction of arrow B, and the swinging crank 14 starts swinging in the direction of arrow A via the left rod 15, and the movable receiving member 16 Starts swinging to the second outer 13B2 side,
The overall length of the outer wire begins to decrease. That is, the engine speed starts to decrease.

When the right steering lever 8 is almost half-depressed, the pivot point Q, the crank pivot point X, and the receiver pivot point Y are arranged in a straight line. The setting is such that the engine speed is reduced by 20% compared to the state. When the right steering lever 8 is further depressed and operated until it is depressed, the crank pivot point X is located below the line connecting the swing fulcrum Q and the receiver pivot point Y. The setting is such that the engine speed is reduced by 10% compared to the open state.

That is, by setting the relationship between the swing angle range of the swing crank 14 and the movable receiving body 16 as described above, the steering lever 8 can be moved more than the engine speed in the released state of the steering lever 8. The speed control linkage mechanism B that links the side clutches 7 and the steering levers 8 is configured such that the engine speed in the gripped state of the engine 8 is lower. In FIG. 2, each rod 15, 15 is interlockingly connected to the swing crank 14 at a different angle for the sake of depiction of the drawing. Rod 15,15
Are also overlapped, and are linked to the swing crank 14 at the same angle.

That is, the relationship between the amount of gripping operation of the steering lever 8 and the engine speed is, for example, as shown in the graph of FIG. At the same time, they are linked so that the engine speed slightly decreases even in the gripped state where the side clutch 7 is disengaged. Therefore, when the side clutch 7 is substantially engaged or disengaged, the driving load on the traveling axle 6 is reduced, the clutch operation can be performed lightly, and the driving speed is reduced in the turning state with the side clutch 7 completely disengaged. Since the steering wheel 4 is slightly dropped and the tendency of the steering wheel 4 to be swung is suppressed, the turning operation can be easily performed.

As shown in FIG. 2, there is provided an adjustment mechanism C capable of variably setting the degree of reduction of the engine speed when the steering lever 8 is depressed. That is, a stopper that determines the swinging movement limit of the swinging crank 14 when the steering lever 8 is gripped is constituted by the bolt 19 that is fixed in position by the lock nut 20. That is, the lock nut 20 is loosened and the fixing member 2 of the stopper bolt 19 is
By adjusting the margin from 1, the movement limit of the swing crank 14 can be arbitrarily set, for example, between 15% and 5% of the engine speed as shown in FIG.
Thereby, the rotation speed in the turning state due to the gripping is reduced to, for example, 15% in a field having a relatively large driving load such as a wetland, to 10% in a general field, and a comparison of the driving load in a dry field or the like. In a very small field, it can be set to 5%.

In the case described above, even when the swinging movement of the swinging crank 14 is the smallest and the gripping 15% is down, the side clutch 7 is already completely disengaged, that is, the steering is performed. Push the lever 8 to the 6
The side clutch disengagement state is made to appear when the driver grips about 70%. Further, there is provided an operation play in which the disengagement operation of the side clutch 7 starts from a state in which the gripping is performed by 20 to 30% of gripping.

Even when the adjusting mechanism C is operated to the maximum speed on the deceleration side, the maximum rotation speed reduction rate during the depressing of the steering lever 8 is prevented from being increased.
Line start position (left end position) shown in the graph
Can be arbitrarily changed by operating the speed control lever 11, and the "decrease" of the engine speed due to the gripping operation of the steering lever 8 is a deceleration rate.

[Another Embodiment] As shown in FIG. 4, a cam 22 swinging around a fulcrum Q,
The temporary deceleration mechanism A and the speed control linkage mechanism B may be constituted by the cam follower 24 with the roller 23. In this case, the movable follower 16 is moved by the tension spring 25 to the cam follower 2.
4 is always in contact. Projection 2 of cam 22
The movable piece 18, which is a part following 2a, is supported at the pivot point Z,
Further, the adjusting mechanism C is configured so as to be movable and adjustable in the radial direction. That is, by operating the adjusting mechanism C to change the radial position of the movable piece 18 which is the rolling surface of the roller 23, the amount of protrusion of the cam follower 24 changes, and the steering lever 8
The decrease rate of the engine speed in the gripping state of
For example, it can be adjusted and set as shown in the graph of FIG.

As shown in FIG. 6, the temporary speed reduction mechanism A may be configured electrically. That is, the crank 26 that is rod-linked to the speed control lever 11 and the governor lever 12a
The stepping motor 3 is capable of connecting an operating rod 27 linked to the motor with an elongated hole and pin mechanism 28 and pulling a governor lever 12a by a wire 29 in a low speed operation direction.
0 is provided. A limit switch 31 operable on the operation lever 10 of the side clutch 7 is provided, and this and a stepping motor 30 are connected to a control device 32. When the steering lever 8 is gripped, the limit switch 31 is turned ON only in the middle of the gripping operation range, and the stepping motor 3 is turned on.
0 operates, and the governor lever 12a is temporarily forcibly operated to the low speed side. When the stepping motor 30 does not operate, the wire 29 is slack, and the speed control operation is not adversely affected.

A temporary speed reduction mechanism A as shown in FIG. 7 may be used. A stepped shaft 34 is fixed to one end of a lever 33 pivotally supported at a fulcrum K on a transmission case (not shown), and the steering wires 9 and
Receiving part 33a of branch wires 9a branched from 9
To form The stepped shaft 34 is rotatable in an axial direction by spline fitting, and is rotatable within a predetermined range by fitting a non-rotatable receiving cam 35 and a roll pin 36 into a long hole, and is movable in the axial direction. The climbing cam mechanism is constructed by fitting the impossible driving cam 37. Receiving cam 3
5 is a proximal wire 3 linked to the governor lever 12a.
8a, a distal end side wire 38b interlocked with the speed control lever 11 is pivotally supported by the lever 33, and the drive cam 3
The two branch wires 9 are attached to the bracket 37a protruding from
a, 9a are pivotally connected.

In operation, when the steering lever 8 is released from the gripping state, both the cams 35 and 37 ride on each other and the proximal end wire 38a is pulled toward the high speed side.
In this state, when the steering lever 8 is grasped, the branch wire 9a is pulled, and the drive cam 37 is rotated to be in a cam occlusion state, the receiving cam 35 moves toward the drive cam 37, and the engine speed is reduced. Become. When the rider still grips, the climbing cam mechanism operates again and the receiving cam 35 moves toward the lever 33 against the biasing spring 39, and the engine returns to the original high-speed state again. Reference numeral 40 denotes a return spring of the drive cam 37.

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 side view of a walking type cultivator.

FIG. 2 is a system diagram showing an operation structure of a side clutch.

FIG. 3 is a diagram showing a relationship graph between a steering lever grip amount and an engine speed;

FIG. 4 is a side view showing a first alternative structure of the temporary reduction mechanism.

5 is a graph showing the relationship between the amount of steering lever grip and the engine speed in the structure of FIG. 4;

FIG. 6 is a system diagram showing a second alternative structure of the temporary reduction mechanism.

FIG. 7 is a partially cutaway side view showing a third alternative structure of the temporary reduction mechanism, and a sectional front view thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Drive wheel 7 Side clutch 8 Steering lever A Temporary deceleration mechanism B Speed control linkage mechanism C Adjustment mechanism

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Satoshi Uchiya 64 Ishizukita-cho, Sakai-shi, Osaka Kubota Sakai Works Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) A01B 69/00 A62D 51/04

Claims (3)

(57) [Claims] 1. A pair of left and right driving wheels (2), (2),
A walking type including a pair of left and right side clutches (7), (7), and a pair of steering levers (8), (8) capable of operating the side clutches (7), (7) separately. A steering device for a tractor, wherein the side clutch (7) is disengaged by gripping the steering lever (8), and the side clutch (7) is gripped by releasing the grip of the steering lever (8). The side clutches (7) and the steering levers (8) are linked so as to be engaged, and the engine speed is temporarily reduced while the steering levers (8) are being squeezed. A steering device for a walking tractor, comprising a temporary speed reduction mechanism (A) for linking each of the steering levers (8) and the engine (1). 2. The side clutch (1), wherein the engine speed in the gripped state of the steering lever (8) is lower than the engine speed in the grip released state of the steering lever (8). The steering device for a walking tractor according to claim 1, further comprising a speed control linkage mechanism (B) that links the steering lever (7) with each of the steering levers (8). 3. An adjusting mechanism (C) capable of variably setting an engine speed when the steering lever (8) is depressed.
The steering device for a walking tractor according to claim 2, further comprising: