JPH03151802A - Automatic steering gear in self-propelled farm working machine - Google Patents

Abstract

PURPOSE:To provide the title steering gear so designed that a spring for neutral restoration is stretchedly suspended between a tie rod and a front wheel shaft, and steering arms to come into contact with ridge sides are respectively projected in an integral manner from the corresponding knuckle supporting shafts, thereby making the title machine run properly along the ridge. CONSTITUTION:A pair of left and right knuckle supporting shafts 23 as automatic steering gear are, via a tie rod 25, are pivotally connected to a pair of front wheels 11 so as to be allowed to make oscillating motion mutually in an integrated manner. A spring 26 for neutral restoration is stretchedly suspended between the tie rod 25 and a front wheel shaft 21 and elastically energized so that both the front wheels 11 are kept so as to enable direct advance at all times. And steering arms 27 to be in contact with the sidewalls of a ridge G are projected in an integrated manner from the respective knuckle supporting shafts 23. Thereby, when the steering arms 27 come into contact with the sides of the ridge G, the contact can be detected by the respective contact plate pieces 29 attached to said arms, and a pair of the front wheels 11 make an oscillating motion followably so as to spontaneously adapt to the arms toward their bending direction, thus properly carrying out seedling planting in the ridge G.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an automatic steering system for a self-propelled agricultural machine, and in particular, by driving the machine body while adapting to the ridges, it is possible to sow seeds, apply fertilizers, etc. to the ridges. It was devised so that various agricultural tasks such as planting seedlings, sterilization, and harvesting can always be carried out in an appropriate state.

<Prior art> The present applicant previously submitted Japanese Patent Application No. 1-2G1113 regarding a self-propelled seedling transplanting device entitled "Seedling transplanting method and device," but has continued to conduct experiments. As a result,
In the case of this prior invention, it has been found that there are the following problems that still need to be improved in practice in relation to the finished state of the ridges.

<Problems to be Solved by the Invention> That is, in the seedling transplanting device of the above-mentioned prior invention, the rear wheel is a drive wheel driven by the engine mounted on the traveling body, and is completed in a type that can self-propel in the field. When planting seedlings in the molded ridges of the field, due to laziness in checking the condition, the worker faces backwards onto the seat and does not manually steer the front wheels. However, there is no guarantee that the vehicle will automatically run correctly along the ridge.

As a result, if the finished state of the enemy's molding is meandering, it will not be possible to plant the seedlings accurately on the longitudinal center line, and the ridge will later lose its shape, or the seedlings that have already been laid may There is no need to worry about tearing or wrinkling the mulch film.

However, if a driver other than the above-mentioned operator were to ride the aircraft in a forward-facing position and perform steering work, the original function of the self-propelled aircraft would be diminished, resulting in labor savings.
It will be inferior to JJ Ka. And, this is not only a matter of planting the seedlings mentioned above, but the same can be said for the subsequent disinfection and harvesting, as well as sowing, fertilization, and other various agricultural operations for shaping the ridges. be.

<Means for Solving the Problems> The present invention is intended to improve the above-mentioned problems, and for this purpose, as an automatic steering device for a self-propelled agricultural machine, a pair of left and right steering devices driven by an engine mounted on a traveling machine is provided. and the rear wheels of
A pair of left and right front wheels are attached to both ends of a front axle that is fixed and horizontally mounted on the fuselage, each of which is freely pivoted at one neck around the edge of the vertical axis via a knuckle support shaft. In a self-propelled agricultural machine that travels across a ridge, the knuckle support shafts of both front wheels are connected by a tie rod so that the pair of left and right wheels can oscillate integrally, and the quirod and the above Between the front axle and the neutral 1nj
By connecting and tensioning the spring material for Iil, both front wheels are elastically biased to maintain a state where they always move straight, and the steering arms that contact the til+ = surface of the ridge are integrally dispatched from the above-mentioned knuckle support shaft. It is characterized by the fact that

<Example> Hereinafter, the configuration of the present invention will be described in detail based on the illustrated example. FIGS. Reference numeral 10) is a running body having a rectangular frame in a plan view, and runs while straddling a ridge (G) using a pair of left and right front wheels (11) and a rear wheel (12). (13) is a seat fixedly supported at the front of the aircraft (lO), (14) is the engine also mounted at the rear, and (15) and (16) are located between the front and rear of the aircraft (lO). 10) are a front and rear pair of a disk support shaft and an intermediate transmission shaft, each of which is supported horizontally and horizontally.

The intermediate power transmission shaft (16) and the disk support shaft (15) are transmission connected via the first belt (17), and similarly the intermediate power transmission shaft (16) and the engine (14) are connected to each other via the second belt (17). (18), both shafts (15) and (16) are rotationally driven by the engine (14).

In that case, as is clear from both figures, the intermediate transmission shaft (16) is transmission connected to the axle (1 & axle) (19) of the rear wheel (12) via the left and right pair of third belts (20). As a result, the traveling machine (10) can run on its own in the field with the rear wheels (12) used as driving wheels and the front wheels (11) used as steering wheels, with each pair on the left and right straddling the ridges (G). However, the ridge (G) may be meandering depending on the molding conditions of both front wheels, so in order to be able to move accurately on its own so that it always adapts to this, the front wheel (G) 11) is also equipped with the following automatic steering system (S).

9th to 9th sections, which extract and show the automatic steering system (S)
In FIG. 14, (21) is a front axle that is fixed and horizontally suspended at the front position of the traveling body (10), and a pair of left and right bearing tubes (22) are formed projecting from both ends of the front axle. (
23) is a pair of left and right knuckle support shafts that are bent in an L-shape when viewed from the front, and the vertical shaft portions thereof are fitted into the bearing tube (22) in a pivoting state that allows free swinging, while the same (The front wheels (11) are each attached to the horizontal shaft portion so as to freely rotate.

(24) is a pair of left and right support pieces that are physically projected forward from the mid-height position of the knuckle support shaft (23) of the front wheel (11), and these support pieces include the front axle (21).
The left and right ends of the horizontal tie rod (25) parallel to the
Each is pivotally connected. Therefore, the front axle (21
) The knuckle support shaft (2) of the front wheel (11) is specially pivoted to
3) can perform a mutual integral oscillating movement about the vertical axis via its tie rod (25).

Furthermore, (26) is connected to the tie rod (25) and the front axle (2).
1) is a spring material for returning to neutrality connected and tensioned between the front and rear of the vehicle, and is composed of a pair of tension coil springs with equal tension on the left and right sides, and is symmetrical on the traveling center line of the traveling body (10). It is distributed and arranged. The pressing force causes the pair of left and right front wheels (11) to be maintained at all times in a straight forward posture.

(27) is a pair of left and right steering arms that are integrally extended forward from the mid-height position of the knuckle support shaft (23), and includes a support stay (28) of a certain length and a front end of the steering arm. It consists of a contact plate piece (29) fixed to the ridge (G), and the contact plate piece (29) faces so as to be able to come into contact with the side wall surface of the ridge (G).

In that case, the contact plate piece (29) can easily come into contact with the ridge (G) (
Although it is formed to protrude, in particular, the inner nitrogen face is curved so as to form a concave curved surface when viewed from the front and a convex curved surface when viewed from above. Therefore, it fits effectively with the side wall surface of the ridge (G), and also comes in contact with the side wall surface of the ridge (G) as much as possible.
) will not lose its shape.

Contrary to Figures 1 to 8, the following stand-up number (30) is a rotating disk for transferring seedlings supported on the traveling body (lO) via the disk spindle (15), and its peripheral edge is A plurality of sets (a total of 4 sets in the figure) of opposing seedling gripping claws (31) and (32) are installed in a radially symmetrical distribution pattern.

One of the clamping claws (31) and (32) is in a fixed state, and the seedling holder is integrally formed to project from the circumferential surface of the de-isk (30) as a stop claw (31).

In this regard, in the figure, the retaining pawl (31) has a one-shaped plate piece shape when viewed from the front, and is fixedly integrated with the plate surface of the disc (30) in a state that extends to one side, but the tip of the pawl is attached to the disc (30). Of course, it may be punched and formed into a continuous body with the disk (30) as long as it protrudes from the circumferential surface of the disk (30) by a certain height and is exposed.

The other of the clamping claws (31) and (32) serves as a movable seedling holding claw (32), and the receiver, together with each of the stop claws (31), has a corresponding positional relationship that allows it to clamp the seedling (M). Under the
Tension coil springs (3) are pivotally attached to one side plate surface (surface) of the disk (30), and are suspended between each of the springs (11) and the plate surface of the disk (30).
3), a pressing force is normally applied in the upright direction to clamp the seedling (M).

As long as the retaining pawl (31) and the elastic biasing force to close it are applied, a fully coiled spring is used instead of the tension coil spring (33), and the holding pawl (32) is attached by winding it around the pivot pin (34). JJ) In any case, if the toes of the presser claws (32) are formed into a forked fork shape as shown in the figure, shaking of the seedlings (M) can be effectively prevented. This can be said to be beneficial in the sense that the layers can be sandwiched with good stability.

(35) is located at approximately the rear half of the disk (30) in the direction of rotation (F), and
This is a cam plate having an arcuate shape when viewed from the side, approaching the one side plate surface (surface) of 0), and is fixed to the fuselage (10) via a support arm (36). .

As will be described later, this cam plate (35) engages with the surface pressing pawl (32) in the process of continuing to rotate after the transfer of the seedling (M) by the disk (30) is completed. Attach the presser claw (32) to the above coil spring (
While resisting the biasing force of 33), the seedling holder is designed to forcibly open and separate from the retaining claw (31) so that it falls down.

In addition, (37) is also located at approximately the front half of the disk (30) in the rotation direction CF), and the cam @
Disk (20) as if facing (35)
This is a large arc-shaped seedling transfer guide cover that covers the circumferential surface of the vehicle, and is also fixedly supported by the body (lO). Seedlings (M) transferred as the disk (30) rotates.
is designed to be guided stably by the guide cover (37).

In that case, the upper end of the guide cover (37) has a disc (
The seedling (M) is introduced into the chute (38) against the circumferential surface of the seedling (M).
), and the so-called bent corner of the shoe ) (38) serves as an inlet (A) for seedlings (M>) relative to the circumferential surface of the disk (30). , seedlings (M) are placed in a prone position from above.

As suggested from the side view of Fig. 1, the input port (A) is located between the front and back of the upper end of the guide cover (37) and the upper end <a> of the cam plate (35). There is.

On the other hand, the lower end of the guide cover (37) is connected to the disk (30).
) facing the lower end of the cam plate (35).
The part corresponding to the front and back of the lower end (b) of is,
It is set as a defined outlet (B) from the disk (30). Needless to say, the outlet (B) is located on the vertical radial line (YY) of the disk (30) and closest to the ridge (G).

(39) (40) is a pair of upper and lower drive rolls and driven rolls facing the seedling input port (A), and the drive roll (39) is driven by the engine (14) into the 1.7.
In contrast to being rotationally driven in the direction of arrow (P) in FIG. 8, the driven roll (40) comes in contact with the driven roll and rotates with it, so that it freely rotates in the opposite direction. Then, the seedlings (M) introduced along shoe 1- (311) are placed on both rolls (39) and (40).
- Once held in place, the disc (30)
As the rotation progresses, the receiver is passed to the stopper claw (31), and can be transferred while being held between the retainer claw (32) and the retainer claw (32).

In that case, as soon as the transfer is completed, the lower driven roll (40) is retracted from the circumferential surface of the disk (30) in a buried manner, as shown in FIG. 7 to the state shown in FIG. , so as not to interfere with the seedling gripping claws (31) (32) of the disk (30).

That is, the driven roll (40) is pivotally connected to the fuselage (10) and the guide cover (37) via the swing arm (41), and is normally attached to the tension coil spring (
42), it is elastically biased into an upright state in which it comes into contact with the drive roll (39). The operating piece (43) integrally extends from the lower end of the swing arm (41).
) is engaged with the detection pin (44) integrally protruding from one side plate surface (surface) of the disk (30), it falls down against the biasing force of the coil spring (42) for the first time, and the disk (30) ) is designed to retreat from the circumferential surface.

The operating piece of the swing arm (41) is attached to the detection pin (44).
43), the seedling (M) is held by the gripping claws (3).
1) The receiver detects that it has been handed over to (32), and the driven roll (40) intermittently falls down each time, and immediately returns to standing on its own. It is.

(45) is a drawing board fixing piece bent at the upper part of the swing arm (41), and both rolls (39) (40
) face-to-face interaction correctly. Above input port (A)
The seedlings (M) introduced from
) together with (40) onto the circumferential surface of the disk (30),
- Good layer stability (plays the role of holding) (46)
is a column that supports the r2 shift arm (41) to the fuselage (10), and (47) is its pivot pin.

The surfaces of both rolls (39) and (40) are given appropriate elasticity to prevent damage to the seedlings (M), but based on the same purpose, the circumferential surface of the disk (30) It is also desirable to integrate the shoulder membrane or to give the circumferential surface of the disc (30) a rounded shape.

Furthermore, on the 4th day, the above discharge port (
Seedling planting is carried out by pricking the root part of the seedling (M) transferred to B) into the ridge (G), and as is clear from Figures 3 to 6, the one side plate where the disk (30) remains The disc (30) is brought into close contact with the front surface (back surface), and moves up and down on the vertical radial line (Y-Y) of the disc (30).

(L) is a four-bar parallel link mechanism that pivotally connects the arm (48) to the fuselage (lO), and the link mechanism (L) further connects the disk ( 30), the rotary movement of the disk (30) can be converted into the lifting movement of the planting arm (48).

In other words, the link arm (49
) is connected to the lower end of the crank arm (51) in the crank movement mechanism (C) via the pivot pin (50). Moreover, the planting is done using an arm (
48) is always in a raised state where it is retracted from the circumferential surface of the disk (30) in a buried manner, and as the disk (30) rotates, when the seedling (M) is transferred to the discharge port (B). For the first time, while descending as if advancing from the circumferential surface,
The relationship is set so that the seedling (M) is received from the disk (30).

Hit, the crank movement mechanism (C) is the engine (14)
The actuating arm (52) of the cam clutch (automatic one-turn clutch) is a separate detection bin ( 53), the planting arm (48) is lowered via the crank arm (51), and then immediately returned to the upper position. There is.

The detection pin (53) is different from the detection pin (44) of the driven roll (40), and the seedling CM) is different from the discharge port CB).
In the figure, there are a total of 4 sets of seedling gripping claws (31) and (32) on the disc (30), so there is a correlation between these and the position of the seedling detection pin (53).
) are also distributed in a radially symmetrical arrangement with a total of four, but it goes without saying that these can be increased or decreased in accordance with the increase or decrease in the number of seedling gripping claws (31) (32).

In addition, for planting, the lower end of the arm (48) is a disk (30).
In relation to the direction of rotation (F), the seedling (M)
The receiver is bent in a form that can be stopped, but it may also be branched into a forked fork shape, for example.

The crank movement [the cam clutch of fl(c) and the intermediate transmission shaft (16) are the fourth bell) (54), and the cam clutch and the drive roll (39) are the fifth bell) (55) 2, the cam clutch and drive roll (39) of the crank movement mechanism (C) are also connected to the fuselage (1
0) will be driven by a ttin engine (14) on top. (56) is a seedling storage magazine that is fixedly supported on the machine body (10) and faces the upper part of the circumferential surface of the de-isk (30). has been done.

Therefore, the operator is traveling machine (10) - Hi no Sho L? ;(1
3) While sitting in the magazine (56), remove the seedlings (
M) may be put into the chute (38) one by one in a prone position parallel to the axis of rotation of the disk (30).

However, instead of such manual feeding method, seedlings (
Of course, a feeder for automatically and mechanically feeding M) may be additionally installed around the feeding port (A).

In the figure, the ridge (G) is covered with a plastic film (57), but it goes without saying that the present invention can be practiced even if seedlings are planted in the ridge (G) that is not covered.

According to the above configuration, the left and right pairs of front wheels (11) and rear wheels (12) of the traveling body (10) are made to straddle the ridge (G), and the rear wheels (12) are placed over the body (10). ) is driven by the installed engine (]4), and the arrow (X) in Figure 1
While traveling in one direction, the operator feeds the seedlings (M) one by one into the chute (38) from above the seat (13) of the machine body (10), so that the seedlings (M) are placed in the furrow (G). Planting can be done automatically and correctly along the lines, and the status of the planting can also be monitored from the seat (13).

That is, the agricultural machine used for planting seedlings is designed to be self-propelled, and its front wheels (11) are equipped with a pair of left and right knuckle support shafts (23) as an automatic steering system (S), and a tie rod (25).
), the tie rods (25) and the front axle (21) are pivotally connected to each other so that they can perform oscillation iLr movement as one unit, and a spring material (2
6) are connected and stretched, so that both front wheels (11) are normally biased to a holding state in which they move straight, and the knuckle support shaft (23) faces the side wall surface of the ridge (G). , a steering arm (27) that can come into contact with the side wall surface is integrally extended.

Therefore, even if the ridge (G) is bent in a meandering manner, the steering arm (27) comes into contact with the side wall surface of the ridge (G), as is clear from Figures 9 to 14. is detected by the contact plate piece (29), and the pair of left and right front wheels (11) follow the bending direction as if adapting to the bending direction, and the head is automatically steered. As a result, the seedlings (M) can be properly planted in the ridges (G) even though the worker rides on the self-propelled machine (10) in a backward position.

The planting action is also achieved automatically and mechanically by driving the rotation of the rotating disk (30).

That is, if the rotating disk (30) for transferring seedlings is driven, as is clear from FIG. 15 (1) to (rV),
As the seedlings (M) introduced from the seedling input port (8) onto the circumferential surface of the disk (30) rotate in the direction of the arrow (F) of the disk (30), the seedling holder is moved by the stopper. (31)
The discharge port (B) is automatically transferred downward while being held between the seedling holding claw (32) and the seedling holding claw (32), and eventually approaches the ridge (G).
), the seedling presser claw (32) touches the cam plate (
By engaging with the lower end (b) of 35), the receiver opens and separates from the stopper claw (31), and the gripping state of the seedling (M) is released.

And, the planting facing the demarcation exit CB) is with an arm (48
) is clear from FIG. 16(1) to (r[I),
At the same time as the above-mentioned release, the seedling (M) is lowered while pulling the root part (JJ), and is planted in the shape of a stab in the ridge (G). If the ridge (G) is covered with a film (57) as shown in the figure, planting can be done by lowering the arm (48).
That film (57) was also torn through.

The presser claw (32) that has released the seedling (M) continues to be locked with the cam plate (35) while the disk (30) is rotating. ) remains open until the seedlings are introduced again and reach I(A).Then, the next seedling CM) that is introduced is caught by the stopper claw (
When the catch is stopped by 31), its presser claw (32)
is released from the upper end (a) of the cam plate (35),
The seedling (M) is then held and transferred to the discharge port (B).

One stroke like this can result in multiple sets of gripping claws (31) (32)
This process is repeated intermittently, so to speak, so that the planting of seedlings (M) can be carried out automatically and mechanically and efficiently.

In that case, the planting is performed using the engine (as shown in the figure) as the crank movement mechanism (C) that raises and lowers the arm (48).
A cam clutch rotationally driven by the arm (48) is adopted, and the planting is carried out intermittently every time the operating arm (52) engages with the detection pin (53) of the disk (30). If it is determined that the arm (4 days) is moved up and down by the amount of the forward movement, the planting arm (4 days) can be moved up and down reliably and quickly, which will help improve work efficiency, and the gripping claws (31) ( 32) can be rationally accommodated in terms of design, and in particular, it is possible to prevent the film (57) from being pierced to an excessively large extent, which is extremely beneficial in practice.

In addition, a driving roll (39) and a driven roll (40) as shown in the figure
) facing between the seedling input port (A) and the disk (30), and then insert the disk (30) from the seedling input port (A).
The seedlings (M) introduced onto the circumferential surface of
39) While holding the seedling (M) in the temporarily fixed state by (40), as the disk (3) rotates, the seedling (M) is automatically received by the clamping claws (31) and (32). If the relationship is set so that the worker can hand over the seedlings (M), when the worker is manually putting in the seedlings (M), the worker will be given down time, so to speak, and will be able to work more easily. Become.

Furthermore, the distance (H) between the lower end of the circumferential surface of the disk (30) and the surface of the ridge (G) (depth for planting seedlings) (H) should be kept constant (and the distance between the disk and the traveling body (10) should be kept constant). (30)
It is also effective to reduce the installation height by rA in advance, or to attach an electric sensor so that the height can be automatically adjusted by its detection function.

In the illustrated embodiment, the present invention was explained as a self-propelled agricultural machine for planting seedlings. The present invention is widely applicable not only to the planting of seedlings, but also to later sterilization and harvesting, fertilization, sowing, and other agricultural machinery, as long as it provides regular agricultural work. It goes without saying that it can be done.

<Effects of the Invention> In summary, the present invention uses the engine (14) mounted on the traveling aircraft (10)! j8 A pair of left and right rear wheels (12) that move, and a front axle (
21) through the respective knuckle support shafts (23),
It is equipped with a pair of left and right front wheels (11) which are freely pivoted at one end of its neck around its vertical axis, and runs with the front wheels (11) and rear wheels (12) straddling the ridge (G). In self-propelled agricultural machines, both front wheels (
The knuckle support shaft (23) of 11) is connected by a tie rod (25) so that the pair of left and right sides can oscillate integrally, and the knuckle support shaft (23) of 11) is connected between the tie rod (25) and the front axle (21). By connecting and tensioning the spring material (26) for returning to neutrality, both front wheels (11) are elastically biased to maintain a state in which they always move straight, and the side of the ridge (G) from the above-mentioned knuckle support shaft (23) is Since the steering arms (27) that come into contact with the wall surface are each integrally projected, the problem of the conventional technology mentioned at the beginning can be reliably improved, and the steering arm (27) that comes into contact with the wall surface is completely independent of the molded state of the ridge (G). It has the effect of automatically planting the seedlings (M) correctly on the longitudinal center line of Kotona (the ridge CG), as well as performing desired operations such as disinfection, harvesting, fertilization, and sowing. Since it is simple and sufficient, it can be said to be extremely useful in achieving mass production effects.

In particular, if the configuration according to claim 2 is adopted, the ridges (G
) will lose its shape afterwards, or the mulch film (57) already laid on it will be torn or wrinkled, making it more effective. Moreover, if the configuration according to claim 3 is adopted, the pair of left and right front wheels (11
) can be maintained stably at all times in its straight-line state, and the mass production effect can be expected to be maximized.

[Brief explanation of the drawing]

Fig. 1 is an overall schematic I11 view showing the present invention applied to a self-propelled agricultural tbll for planting seedlings, Fig. 2 is the same (enlarged plan view), and Fig. 3 is an enlarged slope showing an extracted disk. 4 is a partially enlarged sectional view taken along line 4-4 in FIG. 2, and FIG.
Fig. 6 is a cross-sectional view taken along lines 5-5 and 6-6 in Fig. 4, Fig. 7 is a partially enlarged side view of Fig. 1, and Fig. 8 is a retraction operation of the driven roll corresponding to Fig. 7. Side view showing the condition, No. 9.1
Figure 0 is a slope view and a plan view showing an extracted automatic steering system for the front wheels, Figures 11 and 12 are plan views showing its straight running state and curved running state, respectively, and Figures 13 and 14 are Figures 11 and 12. 15 (1-([
1/) is a side view showing the process of planting seedlings, and Fig. 16(
1) to (III) are front views showing the process of planting seedlings using an arm. (10)・・ (11) ・・ (12)・・ (14)・・ (21)・・ (23)・・ (25)・・ (26)・・ (27)・・ (28) ・・(29)... (G)... (S)... - Traveling body, front wheel, rear wheel, engine, front axle, knuckle support shaft, tie rod, spring material, steering arm, support stay, contact plate piece, ridge, Automatic steering device Fig. 75 1111) (IV)

Claims (1)

[Claims] 1. A pair of left and right rear wheels (12) driven by an engine (14) mounted on a traveling aircraft (10);
), a pair of left and right front wheels (11) are pivotally connected to both ends of a front axle (21) fixed and horizontally mounted on the front axle (21) via knuckle support shafts (23), respectively, so as to be freely swingable about their vertical axes; In a self-propelled agricultural machine that runs with its front wheels (11) and rear wheels (12) straddling the ridge (G), both front wheels (
The knuckle support shaft (23) of 11) is connected by a tie rod (25) so that the left and right pairs thereof can oscillate integrally, and between the tie rod (25) and the front axle (21). By connecting and tensioning the spring material (26) for returning to neutrality, both front wheels (11) are elastically biased to maintain a state in which they always move straight, and the side of the ridge (G) from the above-mentioned knuckle support shaft (23) is An automatic steering device for a self-propelled agricultural machine, characterized in that steering arms (27) that come into contact with a wall surface are each integrally extended. 2. A support stay (28) that projects each of the steering arms (27) forward from the knuckle support shaft (23) of the front wheel (11).
) and a contact plate piece (29) fixedly integrated with the protruding front end of the support stay (28), and the inner wall surface of the contact plate piece (29) is a concave curved surface and a flat surface when viewed from the front. The automatic steering device for a self-propelled agricultural machine according to claim 1, characterized in that the automatic steering device is curved to have a visually convex curved surface. 3. Claim 1, characterized in that the spring material (26) for returning to neutrality is a pair of tension coil springs with equal tension, and is stretched in a symmetrical distributed manner on the traveling center line of the aircraft body (10). automatic steering system for self-propelled agricultural machinery.