JPH035208Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a draft control device for a tractor such as an agricultural tractor.

[Problems to be solved by the prior art and the invention]

Generally, when working with this type of tractor, for example, when a towing machine such as a plow is attached,
The draft force from the work equipment is detected, and if the tractor's traction load becomes too large,
Some machines are equipped with a so-called draft control mechanism that prevents overload by appropriately raising the working machine. However, in the past, this draft force was detected as a linear movement of the actuating rod via the top link to which the work equipment was connected, and the linear movement of the actuating rod in the axial direction was detected by a machine such as a link arm. Draft control was performed through switching control that corresponds to the draft force of the control valve by directly transmitting the signal to the spool side of the control valve via a mechanical connection mechanism. Since the linear movement of the rod is small, it is necessary to provide an amplification function to the mechanical linkage mechanism such as the link arm, and the actuating rod may be twisted around the axis when moving in the axial direction. Since the detection accuracy decreases due to displacement, it is necessary to use a stopper to restrict the displacement around the axis, and the structure of these items inevitably becomes complicated and large. Since it has to be housed in a hydraulic case, the hydraulic case itself has to be large, which has been a problem.

[Means to solve the problem]

In view of the above-mentioned circumstances, the present invention was devised for the purpose of providing a draft control device for a tractor that can eliminate these drawbacks. The actuating rod is interlocked and connected to the rotating shaft of the detector via a connecting means that has the function of converting linear movement into rotation, and the draft force is converted into the amount of change in the rotation angle of the rotating shaft. The detector is configured to perform draft control, and the rotating shaft of the detector is fitted into a long hole on the actuating rod side, so that displacement around the axis of the actuating rod side is regulated. It is something.

With this configuration, the present invention converts the linear movement of the actuating rod due to the draft force directly into the amount of change in rotation angle and detects it with a detector, thereby performing draft control.
Displacement around the axis of the actuating rod can be prevented by the rotating shaft portion of the detector, thereby simplifying the structure and making it more compact.

〔Example〕

Next, one embodiment of the present invention will be described based on the drawings. In the drawing, 1 is a running body of an agricultural tractor, and a plow 4, which is a towing work machine, is attached to the rear of the running body 1 via a three-point link mechanism consisting of a top link 2 and a lower link 3. There is. 5 is a lift arm, and 6 is a lift rod.

The base end of the top link 2 is pivotally connected to the middle part of a link receiver 7 which is swingably attached to the fuselage 1 side via a pivot 7a. is connected to the actuation piece 8. Moreover, an operating rod 10 is integrally fixed to this operating piece 8, and the operating rod 10 includes ammunition receivers 11a and 1 for supporting and holding an ammunition 11.
1b is slidably fitted on the outside. When the link receiver 7 swings about the pivot 7a in response to the draft force being applied to the top link 2, the actuating rod 10 is linearly pushed and moved in the front-rear direction depending on the magnitude of the draft force. I'm starting to do that. Reference numeral 13 denotes a guide arm integrally formed at the front end of the actuating rod 10, and the guide arm 13 has a long hole 13a formed in the front-rear direction. This elongated hole 13a has a hydraulic case 9.
A fixed cylindrical boss shaft 14 is slidably fitted into the boss shaft 14, and a rotation shaft 15a of a draft detector 15 consisting of a potentiometer is further rotatable around the axis. As a result, the rotating shaft portion of the detector 15 is inserted into the elongated hole 13a. The arm 15a fixed to the tip of the rotating shaft 15a and the tip of the guide arm 13 are interlocked and connected via a link rod 16. This is converted into a rotational change, so that the draft detector 15 detects the amount of rotational angle change at this rotational shaft 15a.

In the figure, 17 is the main cylinder for the lift arm, 18 is the lift arm shaft, 19 is the operating arm that connects the lift arm shaft 18 and the main cylinder 17, 20 is the control valve to be described later, and 21 is the operating arm 1.
The link body 21 has one end pivotally connected to the link body 9, and a height detector 22 is provided at the tip of the link body 21 to detect the height of the plow by the lifting and lowering of the lift arm.

On the other hand, FIG. 4 shows a control circuit structure diagram of this embodiment, where 23 is a control section consisting of a microcomputer, and the control section 23 is connected to the draft force detector 15, the height sensor The draft control setting value can be changed by operating the position setting device 22, the position setting device 24, and the draft control lever 25a provided near the driver's seat of the traveling aircraft 1. The signals from the draft setting device _{25 that} can adjust the
It is inputted to IN ₁ and IN ₂ , and the result of calculating these is outputted from the terminal OUT toward the drive circuit section 26. Then, in accordance with a command from the control part 23, the drive circuit part 26 issues a switching control command to the control valve 20 when the lifting height of the plow 2 deviates from the set value, thereby controlling the main cylinder 1.
7 is controlled to expand and contract as appropriate to position the plow 2 at a predetermined lifting height.

In the embodiment of the present invention constructed as described above, when plowing is being carried out, the draft force from the plow 4 is applied to the top link 2,
This is transmitted via the link receiver 7 as a linear movement of the actuating rod 10 in the front and rear direction. In the present invention, this linear movement amount of the actuating rod 10 is converted into a rotation angle change amount and detected by the draft detector 15.
Draft control is now in place.

That is, in the present invention, the actuating rod 10 moves linearly in the front and back direction in response to the magnitude of the draft force, but this linear movement is caused by the rotational movement of the rotating shaft 15a by the link rod 16. The converted state is transmitted to the draft detector 15 side.
Upon receiving this, the draft detector 15 detects the amount of change in the rotation angle of the rotation shaft 15a corresponding to the amount of movement of the actuating rod 10 in the linear direction as the magnitude of the draft force, and this value is sent to the control section 23. It will be input. As a result of calculations based on these input signals, the control section 23 issues a command to the drive circuit section 26 to switch the control valve 20, and performs draft control by vertically raising and lowering the lift arm 5. Become.

In this way, in the present invention, the draft force is generated by locating the rotation shaft 15a of the draft detector 15 on the longitudinal movement line of the actuating rod 10, and converting the amount of movement in the linear movement directly into the amount of change in the rotation angle. The structure of the detection mechanism is simple and compact, and since the detection means is electrical, extremely accurate draft control can be performed. Furthermore, in the present invention, the rotation shaft 15a of the draft detector 15 is inserted into the elongated hole 13a formed in the guide arm 13, so that the rotation of the actuating rod 10 about the axis is restricted. Therefore, the rotation axis of the draft detector 15 can prevent twisting, twisting, or bending around the axis that occurs when the actuating rod 10 receives draft force and moves linearly toward the axis. 15a can be used effectively as is, and a dedicated stopper as in the prior art is therefore unnecessary, and the structure can be simplified in this respect as well.

Furthermore, in this embodiment, the rotating shaft 15a is not directly fitted into the elongated hole 13a of the guide arm 13, but is inserted into the boss shaft 14 in a double structure. During linear movement, the guide arm 13 slides on the rotation shaft 15a and rotates the rotation shaft 1.
The rotation of 5a is not obstructed at all.

[Effect]

In summary, since the present invention is constructed as described above, the linear movement of the actuating rod due to the draft force is caused by the rotation of the rotation axis of the draft detector on the movement line of the actuating rod. The draft force is converted into an operating motion, and the draft force can be detected by the amount of change in the rotation angle of the rotation axis, and draft control can be performed using these. The rotating shaft of the device restricts displacement such as twisting around the axis of the actuating rod, and functions as a stopper, allowing parts to be used for multiple purposes. Complex mechanical connection mechanisms from the rod to the control valve spool and special stoppers and other members to prevent twisting are no longer required.
Not only can the structure be simplified and made more compact, but also accurate draft control can be performed.

[Brief explanation of the drawing]

The drawings show an embodiment of the draft detection device of the draft control mechanism according to the present invention, in which Fig. 1 is an overall side view of an agricultural tractor, Fig. 2 is a vertical sectional view of the main part of the hydraulic case, and Fig. Figure 3 is A-A in Figure 2.
The sectional view and FIG. 4 are control circuit mechanism diagrams. In the figure, 4 is a plow working machine, 10 is an operating rod,
13a is a long hole, 15 is a draft detector, 15a is its rotation axis, and 16 is a link rod.

Claims (1)

[Scope of utility model registration request] The actuating rod, which moves linearly in response to draft force from the working machine, is interlocked and connected to the rotating shaft of the detector via a connecting means that has the function of converting linear movement into rotation, and the draft force is converted into rotation. Draft control is performed by converting the amount of change in the rotation angle of the shaft, and the rotation shaft portion of the detector is fitted into a long hole on the actuating rod side, and the rotation angle around the axis on the actuating rod side is fitted. A draft control device for a tractor, characterized by regulating displacement.