JPH0322902A - Draft controller of tractor - Google Patents

Abstract

PURPOSE:To provide the subject device balancing the compressing and drafting loads applied to a top link, having a simple structure and having a widened working range by disposing a balance spring for the draft control of a tractor above a hydraulic case. CONSTITUTION:In a controller for a draft device wherein a hydraulic case 3 is disposed above the mission case of a tractor and a top like T and a lower link L are lifted and rotated with a lift arm 7 projecting the hydraulic case 3 to lift or lower a traction work machine A, a top link hinge 5 rotating on a pivotally hinge-supporting shaft 4 is disposed and pivotally top link-supporting holes 5a are opened at the rear portions of hinge 5. A balance spring 1 and sensor spring rod 2 are disposed above the hydraulic case 3 to balance both the compression and tension loads applied to the top link T with the balance spring 1 to provide the objective device.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a balance spring for draft control when a tractor is towed with a plow, disc harrow, etc. attached to the rear of the tractor.

(Also) Conventional technology The technology related to balance springs for draft control has been known to the public for some time. For example, in 1975
This technique is similar to the techniques described in Japanese Utility Model Publication No. 166408 and Japanese Utility Model Application Publication No. 59-36908. (c) Problems to be Solved by the Invention However, in the conventional technology, a large balance spring for the compressive load applied to the top link and a small balance spring for the tensile load were arranged in duplicate. Therefore, space was needed for a large balance spring. The present invention makes it possible to balance both the compressive load and the tensile load applied to the top link using a single balance spring. In addition, in order to prevent the hunting and chattering phenomena of work equipment that occur during draft control,
Sensitivity was reduced by increasing the spring constant of the balance spring and changing the link ratio of the links connected from the top link.

In addition, the spring constant of conventional balance springs is linear, so if the field conditions or work machine conditions change with respect to the set spring constant, the position of the top link pivot hole of the top link hinge can be changed. In cases where this could not be covered by the top link pivot hole, balance springs with different spring constants were available as an option. The present invention solves these conventional problems. (2) Means for Solving the Problems The objects of the present invention are as described above, and the structure for achieving the objects will now be explained.Top link hinge 5・Tomb link pivot hole 5a・Hinge It is composed of a pivot shaft 4, a sensor spring rod 2, and a balance spring L, and the balance spring 1 is placed above the hydraulic case 3, and the balance spring 1 prevents compression and tension applied to the top link T. Both loads are balanced. Also, a vibration damping damper 14 is attached to the balance spring 1. Also, the balance spring 1 is a non-linear spring. (E) Example of the present invention The purpose and structure of the apparatus are as described above, and the structure of the embodiment shown in the attached drawings will now be explained. Fig. 1 is a side view of a tractor with a bureau-type working machine such as a burau attached; Figure 2 is a rear view of the hydraulic case 3 and top link hinge 5, Figure 3 is a side view, Figure 4 is a side sectional view, and Figure 5 is a view of the top link hinge 5 and balance spring l. An enlarged sectional view, FIG. 6 is a side view showing the shape of the non-linear spring, and FIG. 7 is a drawing showing the relationship between the load and stroke of the non-linear spring.

In Fig. 1, a towing work machine A is attached by a top link T and two lower links L-L on the left and right. A lift arm 7 protruding from the hydraulic case 3 moves the lower link L-L up and down, thereby raising and lowering the towing work machine A. In the case of deep plowing in which the traction work machine A such as a burau digs deep into the soil, a large traction resistance P is applied to the part where the traction work machine A digs deep into the soil.

This traction resistance P acts on the top link T as a compressive load.

When working with a normal towing work machine A, this large traction resistance P acts and the top link T is almost always subjected to a compressive load. On the other hand, when the towing machine A is in shallow plowing, the traction resistance P is small, so the weight W of the towing machine A becomes larger, and a weak tensile load acts on the top link T. ．． Therefore, the compressive load applied to the top link T is large and the tensile load is small, so the balance spring l has a pressure of 1 [Qi] It was necessary to prepare both a large spring for the heavy load and a small spring for the tensile load. Next, it will be explained with reference to FIGS. 2 to 5.

A hydraulic gauge 3 is arranged on the upper surface of the transmission case of the tractor, and a hydraulic valve V is arranged inside the transmission case on the lower surface of the hydraulic case 3. Further, a position control lever 30 and a draft control lever 3l are arranged on the right side surface of the hydraulic case 3 in the direction of movement. Further, on the left side of the hydraulic case 3, a position feedback link 9 that feeds back the rotation angle of the lift arm 7 and a draft feed bank link 8 that feeds back the rotation angle of the top link hinge 5 are arranged. When the hydraulic valve V is switched to the set value of the position control lever 30 and the lift arm 7 is rotated to a predetermined angle, the hydraulic valve (2) is returned to the neutral position by the position feedback 7 clink 9. In addition, the hydraulic valve V is switched depending on the setting value of the draft control lever 3l, and the compression applied to the top link hinge 5 is
When the tensile load reaches the set value, the draft feedback link 8 returns the hydraulic valve V to the neutral position. As shown in FIG. 4, a cylinder is constructed inside the hydraulic case 3, a piston 17 slides, a piston rod 18 pushes an arm 19, and a lift arm shaft 20 rotates the lift arm 7. A hinge bracket l5 that pivotally supports the top link hinge 5 is fixed to the rear surface of the hydraulic case 3 as described above. Three protrusions protrude from the hinge bracket l5: a pivot shaft support portion 15b, a lock pin support portion 15a, and a balance spring support portion 15c, which insert and support the hinge pivot shaft 4. The lock pin 6 is attached to the candle pin support portion 15a.
is inserted through the hole in the hinge bracket l5 to lock the rotation of the top link hinge 5. A top link locking portion 29 is arranged at the upper end of the top link hinge 5 to lock the toso printer T when not in use. Furthermore, when the lock bin 6 is removed, a lower stopper 26 is disposed below the front of the top link hinge 5 as a stopper when the top link hinge 5 rotates around the hinge pivot shaft 4, and the hinge bracket l5 It is configured to stop when rotated by a distance t1 between the rear surface of the rotor and the rear surface of the rotor.

Further, the upper stopper is constructed between the front surface of the Rondo base lO and the rear surface of the balance spring support portion 15c, and is located at a distance t.
It is designed to stop when it rotates by 2 degrees. Further, the rear part of the plink hinge 5 has two upper and lower top link pivot holes 5a, and the front part has two upper and lower pivot holes 5b for the draft feedback link 8.

Next, referring to FIG. 5, the structure of the balance spring 1 and sensor spring rod 2 will be explained.

The Rondo base 10 is formed into a rectangular parallelepiped, and its front surface is formed into an upper stiff bar as described above, and is configured to abut against the rear surface of the balance spring support portion 15c. Further, the rondo base 10 is pivotally supported on the upper end of the tosobrink hinge 5 by a pivot shaft l6. A sensor spring rod 2 is fixed to the pivot shaft 16, and a spring receiver locking body 2a is fixed to the outer periphery of the base of the sensor spring rod 2. The sensor spring rod 2 and the spring receiver locking body 2a are integrated, but the tension direction spring receiver 11 is slidably fitted loosely into the spring receiver locking body 2a. In a normal state, the rear end surface of the tension direction spring receiver 11 comes into contact with the locking step portion 2b of the spring receiver locking body 2a, and the biasing force of the balance spring 1 causes the spring receiver locking body 2a to connect to the sensor. The spring rod 2 and the rond base 10 are pushed rearward to rotate the tongue link hinge 5 rearward. The tension direction spring receiver 11 has a sliding margin of a distance t3 forward from the position where it abuts against the locking step portion 2b to the position of the vibration damping damper receiver 27.

Further, a vibration damper l4 made of an elastic body is loosely fitted on the sensor spring rod 2 next to a vibration damper damper receiver 27, and a compression direction spring receiver 13 is interposed at the front end of the vibration damper 14. equipped.

The front end of the compression direction spring receiver 13 is positioned in contact with a balance spring fixing body 12 fixed to the upper surface of the hydraulic case 3.

- Also, a double nut 25 whose position is adjustable is screwed onto the front end of the sensor spring rod 2, and the position of the compression direction spring receiver 13 can be adjusted by means of the double nut 25.

Next, let me explain the contraction of the balance spring l in the case of deep plowing. In the case of deep plowing, the traction resistance P applies a compressive load to the top link T, pushing the lower end of the top link hinge 5 forward, and pushing the upper end of the top link hinge 5 and the sensor spring rod 2 backward. The traction resistance P is applied to the

Therefore, the double nut 25 at the front end of the sensor spring rod 2 pushes the compression direction spring receiver 13 rearward to compress the balance spring l. In this case, the compression direction spring bearing 13 simultaneously acts on the sensor spring rod 2.
The vibration damping damper 14, the vibration damping damper receiver 27, and the spring receiver locking body 2a can be pushed at the same time, and the rond base 10
Since it is not locked, the vibration damping damper 14 can freely move back and forth while remaining extended, so the vibration damping damper 14 does not expand or contract. As a result, the vibration damping damper 14 has no role at all when traction resistance P acts during deep plowing.

Conversely, let me explain the case of shallow cultivation.

In the case of shallow plowing, the weight W is applied to the top link T as a tensile load, and the lower end of the tomb link hinge 5 is applied in the direction of pulling backward, and the upper end of the top link hinge 5 and the sensor spring loft 2 are applied to the front. It is applied in the direction of pushing. In this case, since the rond base lO and the spring receiver locking body 2a are integrated, the tension direction spring receiver 1l is pushed by the locking step portion 2b, and the balance spring 1 is contracted.

In addition, the spring receiver locking body 2a pushes the vibration damping damper receiver 27, and the vibration damping damper 1 is pushed by the vibration damping damper receiver 27.
When 4 is pressed, the front end of the vibration damping damper 14 is in contact with the compression direction spring receiver 13, so it cannot move forward, and the contraction of the vibration damping damper 14 starts at the same time. In the case of shallow plowing, the balance spring 1 expands and contracts due to the weight W, but in the case of shallow plowing, the tensile force applied to the tosoplink hinge 5 changes rapidly, and the hydraulic valve V is switched in response to this. Otherwise, it may cause chattering or hunting. In the present invention, when a tensile load is applied to the top link T due to the weight W, the vibration damper 14 acts together with the balance spring 1 to slow down this movement, so the movement of the top link hinge 5 becomes slow and the hydraulic valve This makes V switching slow and eliminates hunting and chattering. In the case of deep plowing, the change in compressive load is not drastic, so even if the vibration damping damper 14 is not changed, no chiming or chattering will occur. Figures 6 and 7 show examples in which the balance spring 1 is non-linear. In this way, the spring constant of the balance spring 1 is not linear but non-linear, and as shown in Fig. 7, the rate of change of the spring load changes with respect to stroke changes, so the controllable top link load range We were able to expand this. Conventionally, the spring constant of the balance spring l was linear and changed at a constant rate of change, so if the field conditions or work machine conditions change with respect to the set spring constant, the top of the top link hinge Change the position of the link pivot hole,
In cases where changes in the top link pivot hole alone could not cover the problem, springs with different spring constants were prepared as optional parts. In the embodiments shown in Figures 6 and 7, the nonlinear constant of the balance spring l is set in three stages a-b-c, and the spring constant is divided into three stages from small to large. ing. When a tensile load is applied to the top link T by the weight 1w, only a small load is applied, so
It operates only in state a, which has the smallest spring constant.

(F) Effects of the Invention Since the present invention is configured as described above, it exhibits the following effects.As claimed in claim (1), the top link hinge 5, top link pivot hole 5a, and hinge pivot Consisting of a support shaft 4, a sensor spring loft 2, and a balance spring 1, one balance spring 1 is placed above the hydraulic case 3, and the balance spring 1 applies both compression and tension to the top link T. By balancing the loads, we were able to expand the range of work applications, and we were also able to simplify the structure of the support part of the balance spring l, making it easier to assemble and reducing costs. It is something.

In addition, by placing the balance spring 1 above the hydraulic case 3, the amount of rearward protrusion of the balance spring 1 and the tosob link hinge 5 is reduced, and the link ratio can be increased, making it possible to use soft springs. It becomes possible to use
This made it possible to receive compression and tension with a single spring.

Furthermore, since there is more space around the hydraulic case 3, it is now possible to mount even long and soft springs.

As claimed in claim (2), by providing the vibration damping damper 14 for the balance spring 1, the balance spring 1 expands and contracts violently during control when a tensile load is applied to the tosob link T due to the weight W in a shallow plowing state. This can be alleviated by the vibration damping damper 14, thereby preventing control hunting and chattering.

As claimed in claim (3), by making the balance spring l a non-linear spring, the top link load can be controlled as widely as possible within a limited spring stroke, and the sensitivity of the spring can be adjusted to suit the working conditions. It was possible to use it.

[Brief explanation of drawings]

Figure 1 is a side view of a tractor with a towed work machine such as a plow attached, Figure 2 is a rear view of the hydraulic case 3 and top link hinge 5, and Figure 3 is a side view of the same.
Fig. 4 is a side sectional view, Fig. 5 is an enlarged sectional view of the top link hinge 5 and balance spring 1, Fig. 6 is a side view showing the shape of the non-linear spring, and Fig. 7 is a side view of the non-linear spring. It is a drawing showing the relationship between load and stroke. W... Weight of work equipment P... Traction resistance l... Balance spring 2... Sensor spring rod 3... Hydraulic case 4... Hinge pivot shaft 5...・Top link hinge 5a... ・Top printer pivot hole

Claims (3)

[Claims] (1) Top link hinge 5/Top link pivot hole 5
Consisting of a hinge pivot shaft 4, sensor spring rod 2, and balance spring 1, one balance spring 1 is arranged above the hydraulic case 3, and the balance spring 1 is arranged above the hydraulic case 3.
A tractor draft control device characterized by balancing both compressive and tensile loads applied to the top link T. (2) A draft control device for a tractor according to claim (1), characterized in that a vibration damper 14 for the balance spring 1 is also provided. (3) A draft control device for a tractor according to claim (1), wherein the balance spring 1 is a non-linear spring.