JPH0132499Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a draft control device for a tractor-mounted working machine.

(b) Prior Art Techniques related to balance springs for draft control devices have been well known.

For example, there is a technique described in Japanese Utility Model Application Publication No. 55-166408.

(c) Problems to be solved by the invention However, in the conventional technology, a balance spring for the top link compression load and a balance spring for the top link tension load are arranged, but both balance springs are arranged. are arranged in series in the front and rear, and have the same diameter and approximately the same spring pressure.

Therefore, in high-traction power working machines such as disc plows and soil-repelling plate plows, balance springs with high spring pressure provide appropriate balance, but in heavy-duty and light-load working machines such as cultivators, the tension The problem was that the balance spring, which had a large spring pressure, did not balance the load properly.

In addition, since both balance springs are arranged in front and behind each other and installed on the same spring guide rod, adjusting the spring pressure of one balance spring will also adjust the spring pressure of the other balance spring, so only one balance spring can be adjusted. There was a problem that the adjustment could not be made.

Furthermore, since both balance springs are arranged in series, there is a problem in that the spring chamber for housing the balance springs becomes too large.

The present invention solves the above-mentioned problems.

(d) Means for solving the problem The purpose of the present invention is as described above. Next, the configuration for achieving the purpose will be explained.

The balance spring of the draft control device that balances the load from the top link applied to the top link hitch 6 is composed of a large diameter balance spring 7 for the top link compression load and a small diameter balance spring 8 for the top link tension load. In this arrangement, the small diameter balance spring 8 is arranged in a double structure inside the large diameter balance spring 7, and the spring pressure of the small diameter balance spring 8 is made smaller than the spring pressure of the large diameter balance spring 7.

(E) Embodiment The purpose of the present invention is as described above, and the structure of the embodiment shown in the attached drawings will be explained.

Fig. 1 is an overall side view of the work equipment control device, Fig. 2 is a side cross-sectional view of the hydraulic case at the center in the left-right direction, and Fig. 3 is a cross-sectional view taken along the line A-A in Fig. 1;
The figure is an enlarged view of the upper part of the control bar in Fig. 3, Fig. 4 is a sectional view taken along the line C-C in Fig. 3, Fig. 5 is a sectional view taken along the line D-D in Fig. 7 is a sectional view taken along the line E-E in the figure, and FIG. 7 is a view taken along the F arrow in FIG. 1.

The hydraulic case 2 is mounted and fixed on a transmission case or a rear axle case.

As shown in the sectional view of FIG. 2, the hydraulic cylinder 17 is fitted into the hydraulic case.
A cylinder head 19 is fixedly installed at the front of the cylinder.

A balance spring device for draft control is provided at the rear of the hydraulic case 2.

The top link hitch 6 is pivotally supported by a pivot shaft 10 that spans between the left and right protrusions of the hydraulic case 2, and is provided through two holes 6a and 6b at the top and bottom of the top link hitch 6.
The front end of the top link is pivotally supported. Left and right spring interposed pins 9, 9 are pivotally supported at the front end of the top link hitch 6 by a pivot shaft 12, and a large-diameter balance spring 7 and a small-diameter balance spring 8 are interposed in a double structure.

Plowing work using a rotary tiller is a case where a compressive load is applied to the top link, but compared to a heavy working machine such as a cultivator, when plowing at a shallow plowing depth and soil resistance is small, the weight of the soil is greater. Overcoming the resistance, a tensile load acts on the top link centering on the lower link. Compressive loads are used when the plowing depth is deep or when working equipment with large soil resistance is used.

In such light-load towing work using heavy work equipment, the plowing depth can be kept constant by compressing the small-diameter balance spring 8 in the opposite direction.

The large stepped portion of the spring interposed pin 9 receives a large diameter balance spring, and the small stepped portion is a stopper portion that abuts the lower end of the spring holder 14 to stop further compression of the lower diameter balance spring.

Further, a stopper for stopping further compression of the small-diameter balance spring 8 is constituted by a spring receiver 15 and the upper end of the spring holder 14.
13 is a top link hook, and 11 is a support plate for the top link hook 13.

Lock nut 1 at the upper end of spring interposed pin 9
6a and an adjusting nut 16b to move the spring receiver 15 up and down to change and adjust the working lengths of the large and small balance springs 7 and 8.

Draft control feedback is number one
In the figure, a pivot shaft 10 of the top link hitch 6 is shown.
The rotation about the hydraulic case 2 is transmitted by the arm 45, the feedback link 46, the pin 57, the arm 49, and the shaft 50 into the case of the hydraulic case 2, and the arm 54, link 43, pin 42, and arm 3 in FIG.
4. The hydraulic pressure is transmitted from the shaft 33 into the hydraulic valve chamber shown in FIG.

In the hydraulic valve chamber, an arm 32 is attached to the tip of the shaft 33.
A pin 31 is fixed to the tip of the arm 32. Draft control bar 2 is on pin 31
The lower end of the top link 3 is pivotally connected, and the draft control bar 23 is moved back and forth according to changes in the traction load applied to the top link.

When a load in the compression direction is applied to the top link hitch 6, the lower end of the draft control bar 23 is pushed forward in FIG. Then, the lower end of the draft control bar 23 is moved rearward to control the lift arm in the lowering direction.

When setting the draft control using the manual setting lever 3, when the manual setting lever 3 is rotated, the lever 3 rotates on the lever guide 5b, and the arm 3a,
The cylinder shaft 24 is rotated by the boss portion 3b, and the cylinder shaft 24 is welded to the engagement piece 27, and rotates the pin 28 fitted into the engagement recess of the engagement piece 27.

The pivot shaft 29 is rotated by the pin 28, and the draft control bar 23 is pivotally connected to the arm 30 below the pivot shaft 29 via the pin 56, so that the upper end of the draft control bar can be rotated back and forth. That's what I do.

The central portion of the draft control bar 23 moves the pin 20 horizontally disposed on the spool 18 of the hydraulic valve 20 back and forth by the combined movement of this manual setting and the vertical movement of the feedback signal.

Next, I will explain the position control device.

The manual setting lever 4 for position control is rotated on a lever guide 5a, and the arm 4
a. Rotate the operating shaft 26 via the boss portion 4b. An arm 25 is fixed to a portion of the operating shaft 26 that protrudes into the hydraulic valve chamber, and moves the upper end of the position control bar 22 back and forth via a pin 44.

A position control feedback signal is transmitted from a lift arm 1 in FIG. Pin 52 from arm 51 of lift arm 1,
Axis 3 via link 41, pin 40, and arm 39
6, a shaft 36 projects into the hydraulic bag chamber of FIG.

In FIG. 3, a cam 36a is integrally provided at the tip of the shaft 36, and a pin 38 of the cam 36a
This moves the lower end of the position control bar 22 back and forth.

Rotate the manual setting lever 4 of the position control to a predetermined position to raise the lift arm a certain amount to the rear of the aircraft, and stop it, the position control bar 22 moves forward as shown in Figure 3, and the spool 18 is pushed in. Switch the hydraulic valve in the upward direction. As a result of this operation, the lift arm 1 begins to rise, and the lower end of the position control bar moves downward in the opposite direction as shown in Figure 3 due to the feedback device, returning the spool from the pushed-in position to the neutral position, and moving the spool to the specified position of the lift arm. It is stopped at the raised position.

As mentioned above, position control and draft control device are used together,
The balance spring of the top link hitch is configured to include large and small diameter balance springs 7 and small diameter balance springs 8, so that the top link can move by the movement width of the small diameter balance spring during light load work using heavy work equipment. .

Therefore, when the draft control manual setting lever is set to a position that enables light load control on this heavy work machine, the work machine can be raised at the edge of the field by operating the position control setting lever 3. and draft control bar 23
The position remains in front of the position control bar 22, and the draft control bar 23 preferentially contacts the spool and operates the relief valve of the hydraulic valve at a certain position. This causes a problem in that the hydraulic pressure is released and the lift arm is placed in the neutral position, causing the lift arm to no longer rise.

However, once the rotation is finished at the edge of the field, the draft control will continue in that state, so we do not want to move the manual setting lever for the draft control, but instead set the draft control bar 23 to move automatically toward the field. A locking member 37 shown in FIG. 5 is provided.

That is, when the lift arm 1 is raised, the pin 35 of the cam body 36a comes into contact with the back of the locking member 37, and the locking member 37 also comes into contact with the pin 31, moving the draft control bar 23 backward to a position where it does not touch the spool. It moves it.

However, since there is a feedback link device on the draft control side, the pin 31 cannot move back, so in FIG. has been set up and absorbed.

In addition, in FIGS. 3 and 3A, friction is applied to the boss portions 3a and 4a in order to stop the manual setting levers 3 and 4 of the draft control and position control at the rotational positions, but this configuration Now, the friction of the boss part is created by four leaf springs 60 loosely fitted to the operating shaft 26, and the tension of the leaf springs is created by screwing in two parallel bolts 67, 68 and seats 65, 66 between them. It's on. This maza 65,
66, the operating shaft 26 is loosely fitted, and the arm 25 and the cylindrical shaft 24 are engaged to prevent the arm 25 from moving outward. It is now possible to move freely.

If the operating shaft 26 moves inward too much,
Since the draft control bar 23 and the position control bar 22 will engage with each other, the gap a between the tip of the operating shaft 26 and the pivot shaft 29 should be adjusted so that the gap a between the draft control arm 23 and the position control arm is the same. The draft control bars are configured to be smaller than the gap b between the closest contact points so that the draft control bars do not engage with each other. 58 and 59 are setting stoppers of the manual setting lever.

(f) Effects of the invention Since the invention is constructed as described above, it has the following effects.

First, high traction power working machines such as disc plows and soil-repelling board plows are balanced by a balance spring 7 with a large spring pressure, and heavy and light load working machines such as cultivators are balanced by springs. Since it is balanced by the balance spring 8 with low pressure, it is not necessary to balance it with a balance spring with a large spring force as in the past, so delicate control is possible in heavy and light load working machines such as cultivators. It is something that has become familiar.

Second, the balance spring 7 has a large diameter and is used for compressive loads, and the balance spring 8 has a small diameter and is used for tensile loads, so that the spring pressure of both springs can be set and adjusted separately, and various This makes it possible to adjust the spring pressure separately to suit different types of work machines.

Thirdly, the large-diameter balance spring 7 for compressive loads and the small-diameter balance spring 8 for tensile loads are arranged in a double structure, so they do not protrude upward into the hydraulic case 2 and are compact. It is now possible to place the

[Brief explanation of drawings]

Fig. 1 is an overall side view of the work equipment control device, Fig. 2 is a side cross-sectional view of the hydraulic case at the center in the left-right direction, and Fig. 3 is a cross-sectional view taken along the line A-A in Fig. 1;
The figure is an enlarged view of the upper part of the control bar in Fig. 3, Fig. 4 is a sectional view taken along the line C-C in Fig. 3, Fig. 5 is a sectional view taken along the line D-D in Fig. 7 is a sectional view taken along the line E-E in the figure, and FIG. 7 is a view taken along the F arrow in FIG. 1. 6... Top link hitch, 7... Large diameter balance spring, 8... Small diameter balance spring.

Claims (1)

[Scope of utility model registration request] The balance spring of the draft control device that balances the load from the top link applied to the top link hitch 6 is composed of a large diameter balance spring 7 for the top link compression load and a small diameter balance spring 8 for the top link tension load. This provision is characterized in that the small diameter balance spring 8 is arranged in a double structure inside the large diameter balance spring 7, and the spring pressure of the small diameter balance spring 8 is made smaller than the spring pressure of the large diameter balance spring 7. Agricultural tractor work equipment control device.