JPH0542896Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a turning mechanism in a front wheel steering vehicle.

(b) Prior Art Conventionally, as shown in FIG. 11, in a front wheel steering vehicle, a front wheel b and a rear wheel c are attached to the front and rear of a body a, and the front wheel b is steered by a steering wheel or the like. In order to avoid steering with the oil pan located in the center of the aircraft body a, there is a restriction on the steering angle θ of the front wheels b, so the turning radius R1, R2 of the left and right front wheels b is limited.
Since the turning center O of the rear wheel C was also located at a considerable distance l1 in the width direction from the center C of the rear wheel c, the turning radii R1 and R2 became large, making it impossible to make sharp turns. .

(C) Means for solving the problem In this invention, the central part of the front axle case is pivoted to the aircraft body so that it can swing freely in the front and back directions, and the front wheels are attached to both ends of the front axle case so that they can swing in the left and right directions. A tie rod that is movably pivoted and interlocks the front wheels is slidably inserted into the rod insertion hole of the rod support protrusion protruding from the front axle case, and the tie rod is inserted into the center of the tie rod and connected to the front axle case. One end of an L-shaped tie rod operating lever is attached to the upper surface of the central part so as to be horizontally rotatable, and the steering handle of the steering mechanism is interlocked and connected to the other end of the lever via a drag rod. A turning mechanism for a front wheel steering vehicle is provided in which a spring is wound around a portion of a tie rod located between a supporting protrusion and a connecting portion at one end of a tie rod operating lever, and the spring enables rocking operation of a front axle case. That is.

(d) Functions and Effects With the above configuration, the present invention has the following functions and effects.

When the tie rod operating lever reaches a certain rotation angle, one of the springs contracts slightly and the front wheel rotates in the left and right directions. Since the elastic restoring force of the spring acts strongly, the front axle case rotates in the longitudinal direction via each rod support protrusion.

When returning the steering handle to its original position, the elastic restoring force of each contracted spring allows the steering handle to be returned easily.

Not only is the front wheel swingable left and right at both ends of the front axle case, but the front axle case itself can swing back and forth, so even if the turning angle of the front wheel relative to the front axle case is restricted, the apparent The steering angle can be increased, making it possible to turn with a small turning radius by only slightly operating the steering mechanism.

When turning, it is possible to increase the turning angle of the front wheels by swinging the front axle case, so the turning angle of the front wheels relative to the front axle case can be reduced, and dirt caused by swinging of the front wheels can be reduced. It is possible to reduce the amount of food being carried around, and the field will not be damaged.

(e) Examples The present invention will be specifically described below based on examples shown in the attached drawings.

In Figure 1, A is a tractor, and aircraft 1
Front wheels 2, 2 and rear wheels 3, 3 are provided at the front and rear of the tractor A, respectively, and the tractor A can perform a turning operation using a turning mechanism B, which will be described below.

In FIGS. 1 to 4, 4 is a front axle case disposed in the horizontal direction at the front of the aircraft 1, and the front axle case 4 is
Its center part is pivoted 5' to a support frame 5 so as to be able to swing freely in the vertical direction, and the support frame 5 is pivotably supported on the front lower surface of the fuselage 1 by a pivot support shaft 6 so as to be pivotable horizontally. has been done.

With this configuration, the front axle case 4 is pivotally supported with respect to the body 1 so as to be swingable in the vertical direction and the longitudinal direction.

Further, the front axle case 4 pivotally supports front wheels 2, 2 via king pins 7, 7 at both ends thereof so as to be swingable in the left-right direction.

Furthermore, knuckle arms 8, 8 are attached around the king pins 7, 7, and both knuckle arms 8, 8 are connected by both ends of a tie rod 9 that extends in the transverse direction parallel to the front axle case 4.

On the other hand, an L-shaped tie rod operating lever 10 is attached to the upper surface of the central part of the front axle case 4 so as to be horizontally rotatable.
, the tip of the rear extending portion 10a is pivotally connected to the center portion of the tie rod 9, and the left end of the left lateral extending portion 10a is connected to the drag rod 1.
1. Steering mechanism D via Pittman arm 12
It is interlocked and connected with the steering handle 14 of.

With this configuration, when the steering wheel 14 is turned, if the steering angle (turning angle) is within a certain small angle range as during normal driving, the drag rod 1
1, tie rod operating lever 10, tie rod 9,
The front wheels 2, 2 can be rotated in the left-right direction around the king pins 7, 7 via the knuckle arms 8, 8.

Furthermore, in the present invention, rod support protrusions 15 and 16 are provided on the rear surface of the left and right sides of the front axle case 4 so as to protrude rearward, and the rod support protrusions 15 and 16 are provided in the rod insertion holes 15a and 16a provided at the tips of both protrusions 15 and 16. tie rod 9
The springs 17 and 18 are slidably inserted through the springs 17 and 18 and are wound around the circumferential surfaces of the portions 9a and 9b of the tie rod 9 located between the respective projecting pieces 15 and 16 and the pivot portion 10c at the tip of the rear extension portion 10a. I am intervening.

With this configuration, the tie rod operating lever 1
0 reaches a certain rotation angle, one of the springs 17, 18 contracts slightly and the front wheels 2, 2 only rotate left and right around the king pins 7, 7 as described above, but the same lever When the rotation angle of 10 exceeds a certain level, either spring 1
Since the elastic restoring forces 7 and 18 act strongly, the front axle case 4 rotates in the front-rear direction around the rotation support shaft 6 via the respective rod support protrusions 15 and 16.

Then, when returning the steering wheel 14 to its original position,
The elastic restoring force of each of the contracted springs 17 and 18 allows for easy return.

When no turning force is applied to the front axle case 4, the front axle case 4 is always in a position extended in a direction perpendicular to the axis X--X of the tractor A as shown in FIG. 10 by the two springs 17 and 18.
Or it can take the position (Y-Y).

Further, a rotary lock protrusion 5a is protruded from the center of the front end of the support frame 5, and the protrusion 5a is engaged with left and right locking pieces 19 and 20 protruding from the fuselage 1 at a certain interval. It is possible.

Therefore, the front axle case 4 is attached to the support frame 5.
The support frame 5 rotates in either the left or right direction via the
The rotation lock protrusion 5a provided on the left and right locking pieces 1
When engaged with either 9 or 20, rotation of the case 4 is restricted.

Next, the turning operation of the tractor A by the turning mechanism B having the above configuration will be explained with reference to FIG. 10.

When the tie rod operating lever 10 is rotated via the drag rod 11 when it is necessary to cut only within a certain small angle range, such as during normal driving, only one of the springs 17, 18 will contract slightly. Since no large elastic restoring force is generated, only the front wheels 2, 2 rotate in the left-right direction around the king pins 7, 7 via the tie rods 9 and the knuckle arms 8, 8.

On the other hand, when it is necessary to turn the front wheels 2, 2 sharply, such as when turning, by rotating the tie rod operating lever 10 via the drag rod 11, one of the springs 17, 18 is greatly contracted, and the same The elastic restoring force of the springs 18, 18 acts on either of the rod support protrusions 15, 16, and first the front axle case 4
is rotated left and right around the rotation support shaft 6, and the front wheels 2, 2 are also cut along with the same rotation.

In this way, when turning, not only can the front wheels 2, 2 be freely swung left and right at both ends of the front axle case 4, but the front axle case 4 itself can also be swung back and forth.
Even if the turning angle of the front wheels 2, 2 relative to a front axle case 4 is restricted by the engine, the oil pan, etc., the apparent steering angle α can be made large, and turning with a small turning radius is possible by only slightly operating the steering mechanism D.

That is, in FIG. 10, R1 and R2 indicate the turning radius of the left and right front wheels 2, 2, and O indicates the turning radius of the left and right front wheels 2, 2.
indicates the center of rotation.

As shown in the figure, O is the center C of the left and right rear wheels 3, 3.
Since they are located at a smaller distance l2, the turning radii R1 and R2 can be made significantly shorter.

Furthermore, when turning, the turning angle of the front wheels 2, 2 can be increased by rocking the front axle case 4, so the turning angle of the front wheels 2, 2 with respect to the front axle case 4 can be reduced. Therefore, it is possible to reduce the movement of soil caused by the swinging of the front wheels 2, 2, and the field is not damaged.

Furthermore, as shown in FIG. 10, after fixing the front axle case 4 at a position cut at a certain angle α by the rotation lock protrusion 5a,
By operating the steering handle 14, it is possible to further turn the front wheels 2, 2 with a required swing width β at the same angle α position, or to soften the turning angle.

Moreover, if the steering force of the steering handle 14 is loosened,
The front axle case 4 has a spring 17,
By the action of 18, it is possible to assume the normal running posture as shown in FIG.

In FIG. 4, 4a and 4b are receivers protruding from the upper surface of the left and right sides of the front axle case 4, and when the case 4 swings upward, each receiver 4a, 4b
are in contact with the lower ends of the left and right sides of the fuselage 1.

Moreover, FIGS. 5 to 9 show turning mechanisms E, F, and G as other embodiments, and each mechanism E,
F and G will be explained in detail below.

That is, the turning mechanism E shown in FIGS. 5 to 7
A rack gear 31 is provided at the front end of the support frame 30,
Switches 33 and 34 for operating the motor 32 by engaging the drive gear 32a of the support frame swinging motor 32 provided in the body 1 with the gear 31 are arranged near the front and rear of the Pitman arm 12, respectively.
35, 35' are stoppers.

With this configuration, the tie rod operating lever 1
0 until a certain rotation angle, the front wheels 2, 2 only rotate in the left-right direction around the king pins 7, 7, but when the rotation angle of the same lever 10 exceeds a certain level,
That is, when the pitman arm 12 rotates to the extent that it activates the switches 33 and 34 disposed near the front and rear, the support frame swing motor 32 is activated, and the support frame 30 is moved in the left and right direction via the respective gears 32a and 31. By swinging, the front axle case 4, which is pivotally supported by the support frame 30, rotates in the left-right direction around the rotation support shaft 6.

In addition, as shown in FIG.
A large-diameter internal gear 44 provided on the upper part of the front axle case 43 is attached to the lower end of the supporting machine frame 40 via a bearing 45 so as to be swingable up and down. .

A vertical shaft 46 is pivotally supported on the supporting machine frame 40,
The upper end of the vertical shaft 46 is connected to the steering handle 1 of the steering mechanism D.
4 through a drive shaft 47, the lower end of the vertical shaft 46 is interlocked with the center portion of the tie rod 49 through an operating lever 48, and a pinion gear is provided in the middle of the vertical shaft 46. 5
0 is meshed with a large diameter internal gear 44.

In the figure, 51 and 52 are the first and second transmission shafts for driving the wheels, and the front axle case 43 is the first and second transmission shafts for driving the wheels.
It swings left and right around the transmission shaft 51.

Further, as shown in FIG. 9, the turning mechanism G has a vertical shaft 60 supported by a front axle case 61,
A pinion gear 64 provided on the same vertical shaft 60 is meshed with a large diameter external gear 63 provided on the support frame 62.

According to such turning mechanisms F and G, when the steering handle 14 is operated, the wheels are swung left and right via the tie rods 49, and the front axle cases 43 and 61 are swung back and forth, thereby achieving a small turning radius. It is possible to rotate the

[Brief explanation of the drawing]

FIG. 1 is an explanatory plan view of the main parts of a tractor having a turning mechanism according to the present invention. Figure 2 is an enlarged plan view of the main parts. Fig. 3 is an enlarged side view with a partial cutaway of the main part. Figure 4 is an enlarged front view of the main part. FIGS. 5 to 9 are explanatory diagrams of other embodiments. FIG. 10 is an explanatory diagram of the operation of the turning mechanism. FIG. 11 is an explanatory diagram of a conventional turning mechanism. A...tractor, 1...body, 2...front wheel, 4
...Front axle case, 9...Tie rod, 10...Tie rod operation lever, 15, 16
... Rod support protrusion, 15a, 16a... Rod insertion hole, 17, 18... Spring.

Claims (1)

[Scope of Claim for Utility Model Registration] a) The central part of the front axle case 4 is pivoted to the fuselage 1 so as to be swingable in the longitudinal direction,
Front wheels 2 are attached to both ends of the same front axle case 4,
(b) A tie rod 9 that interlocks and connects the front wheels 2 and 2.
are inserted into the rod insertion holes 15a, 1 of the rod support protrusions 15, 16 protruding from the front axle case 4.
6a in a slidable manner, and c) connect one end of an L-shaped tie rod operating lever 10, which is horizontally rotatably attached to the upper surface of the center portion of the front axle case 4, to the center portion of the tie rod 9; , the steering handle 14 of the steering mechanism D is interlocked and connected to the other end of the same lever 10 via the drag rod 11; The springs 17 and 18 are wound around the portions 9a and 9b of the tie rod 9, and
A turning mechanism in a front wheel steering vehicle that enables rocking operation of the front axle case 4 by means of 7 and 18.