JPS5928403A - Traction resistance control apparatus in tractor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a traction resistance control device for a tractor or the like in which a working machine such as a plow is connected via a linkage mechanism.

The conventional traction resistance control device has a dedicated link mechanism (draft control link mechanism) that operates the control valve for lifting and lowering the work equipment, and this is linked to a detection device that detects the traction resistance of the work equipment. As a result, the link mechanism dedicated to the draft control is installed alongside the link mechanism for tilling depth control (link mechanism for position control), resulting in a complicated and expensive structure.

The present invention is devised so that traction resistance can be controlled using a link mechanism for tillage depth control, and also has a structure that prevents deformation or damage to members even if traction resistance changes suddenly. The present invention provides a simple traction resistance control device, which will be described below.

The traction resistance control device according to the present invention includes a control valve operation mechanism for operating a hydraulic lifting device that adjusts the vertical position of a work machine connected by a link device, and a control valve operating mechanism for operating a hydraulic lifting device, which is connected by a link device, and a control valve operating mechanism for controlling a work machine. A detection device that detects traction resistance by deformation of an elastic body is connected via a connecting rod, and when the traction resistance becomes larger than a set value, the work equipment is raised. It is characterized in that it is connected to the detection device or control valve operating device via a leaf spring that absorbs shocks caused by sudden changes in resistance.

Embodiment 1 shown in the drawings: Figure 1 is a side view of a tractor equipped with a plow, which is a working machine, and a working machine 2 is attached to the rear of the tractor 1 with a pair of left and right lower links. 3, 3 and one top link 4. The middle part of the lower link 3.3 is connected to a lift arm 6.6 by lift rods 5,5. The lift arm 6 is rotated up and down by a hydraulic device 9 provided at the upper part of the transmission case 7, and raises and lowers the working machine. The hydraulic system 9 includes a hydraulic cylinder 10 as shown in FIG. 2, and hydraulic pressure is supplied to the hydraulic cylinder 10 via a control valve 11'ii. The spool 12 of the control valve 11 is provided so as to be movable left and right, and is pulled to the right by a tension spring 13. When this spool 12 is moved to the left, the control valve 11 is switched so that the piston rod 14 of the hydraulic cylinder 1° protrudes to the right, and the control valve 11 is switched so that the piston rod 14 of the hydraulic cylinder 1° protrudes to the right. Rotate the lift arm 6 upward. On the contrary, spool 12
When the hydraulic cylinder 10 is moved to the right, the hydraulic cylinder 10 contracts and the lift arm 6 is rotated downward. In addition, spool 1
When the hydraulic cylinder 1o is at an intermediate position between the left and right movement positions, the hydraulic pressure of the hydraulic cylinder 1o is maintained as it is, and the neutral state is maintained.

As shown in FIG. 3, the link mechanism for tillage depth control includes a rotatably provided operating shaft 19 that completely penetrates the side wall 17a of the cylinder case 17 of the hydraulic device 9, and a cylinder case attached to the operating shaft. 17, and the base of an L-shaped link 21 is pivotally connected to this operating shaft 19, and one end of this L-shaped link 21 is attached to the lift arm 6 as shown in FIG. The middle part of a position link 23 is pivotally connected to the other end of the L-shaped link 21 with a pin 24, and an elongated hole provided at the lower end of the position link 23 is connected to the rotation base of the L-shaped link 21 via a link 22. A pin 25 implanted in the spool 12 is inserted into the spool 12, and the entire upper end of the position link 23 is connected to the arm 20 with a pin 26.

Further, on the outside of the cylinder case 17, the base of an L-shaped lever 27 formed in a roughly oval shape is fixed to the operation shaft 19, and a tension spring 2 is attached to the upper part of the L-shaped lever 27.
9 are connected and biased to pull the upper part 27at of the L-shaped lever 27 toward the back side of FIG. 3. A fan-shaped lever guide 30 is attached to the outside of the cylinder case 17 with bolts 31. A support shaft 32 is fixed to this lever guide 30, and a lifting position adjustment lever (position lever) 33 is attached to this support shaft 32. is rotatably attached. The lifting position adjustment lever 33 is a holding bolt 3 inserted into a guide arc groove provided in the lever guide 30.
4 so that it can be fixed at any rotational position, and a lower arm 35 that hangs down from the lower part abuts the L-shaped lever 27 from the rear (from the front side in FIG. 3).

When the lift arm 6 is in the upper position, if the lifting position adjustment lever 33 is rotated toward the back side (counterclockwise in FIG. 2) of FIG. The lower part 27b of the L-shaped lever -27 that is biased toward the front side rotates in the direction of the force, causing the operating shaft 19 to rotate in the same direction. This rotation of the operating shaft 19 is transmitted to the position link 23 via the arm 20 and the pin 26, causing the position link 23 to rotate counterclockwise in FIG. 2 about the pin 24f. Therefore, the spool 12 moves to the right in the figure, and the lift arm 6 descends.

In this case, since the link 22 also descends together with the lift arm 6, the L-shaped link 21 rotates clockwise in FIG. Rotate clockwise around 26. Therefore, the spool 12 is moved to the left in the figure and returned to the neutral position, and the control valve 11 stops discharging pressure oil from the hydraulic cylinder 10. In this way, the lift arm 6 maintains the position set by the elevation position adjustment lever 33.

Next, the traction resistance detection device 40 is shown in FIGS.
As shown in the figure, a pair of concentric cylindrical boss portions 41, 41 on the left and right
For installation with 44.', the base 42 is attached to the rear end of the transmission case 7 of the tractor 1 with bolts, and for the pair of attachments where the top link 4 is removed by a pin 43, 44.
A connecting member 45i having a length of 44"t is connected by one torsion bar 46. The connecting member 45 is attached to the part 4.
4.44', and both ends of the torsion bar 46 passing through the cylinder part 47 are attached to the base 42 by inserting them into the cylindrical boss parts 41 and 41'. It is held between the boss parts of both cylinder parts. Torsion bar 4
6 is made of an elastic rod, one end (the left end in FIG. 4) is fixed to the cylindrical boss 41 with a pin 48, and the other end is rotatable to the other cylindrical boss 41'. When fitted, it is fixed to the cylindrical portion 47 by a pin 49 at a position inside the stopper. An intermediate portion between the two fixed portions of the torsion bar 46 is a small-diameter load sensing portion 46a.

For one attachment, a protruding piece 50 is integrally provided on the portion 44', and a leaf spring 51 is fixedly attached to this protruding piece 50. The upper end portion 51a of the leaf spring 51 is formed into an annular shape as shown in FIGS. 6(a) and 6(b) +C, and the shaft 53 of the connector 52 is inserted into this portion. A mounting hole is drilled in the boss portion 54 of the connecting tool 52, and the rear end threaded portion 56 of the connecting rod 55 is fitted into this hole.
It is fixed by nuts 57.57'. A seat 59 is integrally provided on the cylindrical portion 47 of the connecting member 45, and a bolt 60 screwed onto the seat 59 is in contact with the base 42. By doing this, the torsional torque of the torsion bar 46 can be adjusted.

The base of the traction resistance adjustment lever 62 is rotatably fitted into the support shaft 32, and the traction resistance adjustment lever 62 is rotated along the arcuate groove of the entire lever guide 30, and the bolt 63 is rotated.
It can be fixed in any position. A feedback arm 65 is rotatably fitted into a pin 64 fixed to the traction resistance adjustment lever 62, and its lower end abuts the lower portion 27b of the L-shaped lever 27 from behind. The feedback arm 65 is urged to rotate backward by a spring 66, and the front end of the connecting rod 55 is locked at the intermediate portion thereof.

In the above configuration, if the vertical position adjustment lever 33 is fully rotated in the lowering direction and the lower arm 35e is separated rearward from the L-shaped lever 27, the rotational movement of the feedback arm 65 (thus, the L-shaped lever 27 is released). The shaped lever 27 is rotated, and traction resistance control is performed.

The pulling resistance acting on the work implement 2 acts in the right direction of arrow P through the toppling link 4'f connected to the front upper part of the work implement 2, and causes the torsion bar 46, which is an elastic body, to tear around the pin 48 as a fulcrum. Become. When the traction resistance exceeds the torsional rigidity set in the torsion bar 46, the connecting member 45
When the connecting rod 55 is attached, the portions 44 and 44' rotate forwardly about this, and the connecting rod 55 is moved forward. Therefore, the feedback arm 65 rotates forward about the entire center of the pin 64, and the L-shaped lever 27 also rotates forward, so that the spool 12 moves in the direction of raising the working machine and lifts the lift arm 6. Regarding this, as mentioned above, the L-shaped link 2
1 rotates clockwise to return the spool 12 to the neutral position,
The work implement 2 is held in that position. In this way, the traction resistance remains constant.

When the suction resistance adjustment lever 62 is rotated from the position shown by the solid line in FIG. , the lower part 27b of the L-shaped lever 27 is rotated toward the lowering side of the working machine. Therefore, the work implement 2 is lowered to a position determined by the position of the L-shaped lever 27, and the traction resistance generated at this position is therefore set by the traction resistance adjustment lever 62.

A stopper bolt 70 is attached to the lever guide 30, and when the traction resistance transmitted to the top link 4 becomes excessive and the connecting rod 55 moves forward greatly, thereby causing the lift arm 6 to move up and rotate excessively, Just before the arm 16 collides with the cylinder case 17, the L-shaped lever 27
The lower part 271) of the stopper bolt 70 comes into contact with the stopper bolt 70 to prevent its rotation. At this time, the leaf spring 51 bends and absorbs the excessive force, thereby preventing deformation of the connecting rod 55 and the like.

Since the traction resistance control device according to the present invention is configured as described above, the detection device detects the traction resistance of the work machine, and the connecting rod 55 transmits this to the control valve 11 of the hydraulic system for lifting and lowering the work machine. This makes it possible to control the lifting and lowering of the work equipment so that the traction resistance reaches a preset value. Since the traction resistance side is performed using a conventional plowing depth control link mechanism, the structure is simple and inexpensive. Furthermore, since the connecting rod 55 is connected via the leaf spring 51, even if there is a sudden change in traction resistance, the impact is absorbed by this leaf spring, preventing deformation or damage to members such as the connecting rod. Now protected. Leaf springs, which serve as cushioning materials, have excellent shock absorption properties, are easy to install, and are inexpensive. It is also possible to absorb the force from the traction resistance adjustment lever 62 by this leaf spring.

[Brief explanation of the drawing]

Figure 1 is a side view of a tractor equipped with a plow, Figure 2 is a partial sectional view of the hydraulic system, Figure 3 is a sectional view of the control valve operating section, Figure 4 is a rear view of the part where the detection device is installed, and Figure 5 is a side view of the traction resistance control device, Figure 6 (a),
(b) is a side view and a five-sided view of the leaf spring. All figures are examples of gold hail. 1...Tractor 2...Work+i 3.
... Lower link 4 ... Tonneau printer 5 ... Lift rod 6 ... Lift arm 9 ... Hydraulic system 10 ... Hydraulic cylinder 11 ... Control valve 12 ... Spool 19 ... Operation axis
21... L-shaped link 23... Position link 27... L-shaped lever 30... Lever guide 33... Lifting position adjustment lever 40... Detection device 46... Torsion bar 51. ...Plate spring 55...Connecting rod

Claims (1)

[Claims] (1) A control valve operation mechanism for operating a hydraulic lifting device that adjusts the vertical position of the work equipment connected by a link device, and a deformation of an elastic body to reduce the traction resistance transmitted through the link for connecting the work equipment. The system is connected to a detection device for detecting by a connecting rod through a connecting rod, and is configured to raise the work equipment when the traction resistance becomes larger than a set value, and the connecting rod is configured to detect shocks caused by sudden changes in the traction resistance. A traction resistance control device for a tractor or the like, characterized in that the device is connected to the detection device or the control valve operating device via a leaf spring that absorbs the traction resistance.