JPH0681202U - Draft control device for tractor - Google Patents

Abstract

(57) [Summary] [Purpose] By performing towing work while allowing free rotation of the towing type working machine, traveling stability and working accuracy are significantly improved, and no special mechanism is provided on the working machine side. It is not necessary to provide the above, and it can be used with existing work machines. [Structure] The top link 10 is configured to be expandable and contractible to allow free rotation of the multiple plows 3 with the working machine side lower link connecting pin 14 as a fulcrum, and to control the rotating position to a constant level. To control.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a draft control device for a tractor to which a pulling work machine such as a plow or a subsoiler is connected.

[0002]

[Problems to be Solved by Prior Art and Invention]

 Generally, the draft control device of this type of tractor detects the traction resistance from a tow type working machine such as a plow based on the pressing force of the top link (or the pulling force of the lower link) and the lift arm based on the detection. It is configured to maintain a constant pulling resistance by controlling the vertical movement of. However, in the past, the top link was connected to the machine body so that it could slightly move against the ammunition, and the traction resistance was detected based on the displacement of the connected top link. Although the traction resistance transmitted is slightly damped by the ammunition, it almost directly acts on the airframe, and as a result, the traveling airframe acts on the lower link and the pulling force acting on the lower link. A large moment acts in combination with the pressing force, and especially when a work machine with a large traction resistance such as multiple plows is towed, an excessive moment acts on the machine and the operation of the machine becomes unstable. It was the actual situation that it was stored.

[0003]

[Means for Solving the Problems]

 The present invention was devised with the aim of providing a draft control device for a tractor capable of eliminating these drawbacks in view of the above-mentioned circumstances. A tractor in which a tow type working machine is connected via a lower link that actively moves up and down based on hydraulic operation and a top link that passively moves up and down as the lower link moves up and down. The top link connecting part of itself or the machine side is provided with a flexible mechanism for allowing free rotation of the working machine with the lower link connecting part of the working machine as a fulcrum, and the hydraulic control valve of the lift arm is provided with It is characterized in that draft control means for raising and lowering the lift arm is connected to maintain a constant posture of the accommodation mechanism. With this configuration, the present invention remarkably improves running stability and work accuracy, eliminates the need for a flexible mechanism on the work machine side, and allows existing work machines to be used. is there.

[0004]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a traveling machine body of a tractor, and a multi-row plow 3 is movably connected to a rear portion of the traveling machine body 1 via an elevating link mechanism 2 described later. The multiple plows 3 are connected to the elevating and lowering link mechanism 2 in a vertical posture, project from the connecting frame 4 rearward, and rotate approximately 180 ° in the axial direction based on the expansion and contraction operation of the hydraulic cylinder 5. Beam 6, three plows 7a, 7b, 7c arranged in parallel above and below the beam 6, ruler wheels 8a, 8b, 8c, auxiliary plows arranged in front of the plows 7a, 7b, 7c It is composed of 9 etc. The multiple plow 3 configured as described above balances the downward (clockwise direction in FIG. 1) moment based on its own weight and the upward (counterclockwise direction in FIG. 1) moment based on traction resistance. One plow operation is performed and the plowed soil is inverted to the left or right side, but the upper and lower plows 7a, 7b and 7c are alternately used based on the expansion and contraction operation of the hydraulic cylinder 5. Therefore, the reversal direction of the plowed soil can be switched alternately every time the aircraft turns.

The elevating link mechanism 2 is configured as a so-called three-point link mechanism by a single top link 10 and a pair of left and right lower links 11. The pair of left and right lower links 11 actively move up and down based on the hydraulic operation of the lift arm 13 connected through the lift rod 12, while the single top link 10 moves up and down the lower link 11. With this, the elevator 10 is passively moved up and down, but the top link 10 of this embodiment is expanded and contracted to allow the free rotation of the multiple plow 3 with the lower link connecting pin 14 on the multiple plow 3 side as a fulcrum. It is freely configured. That is, the distal end side link portion 10b is slidably fitted into the base end side link portion 10a of the top link 10 formed in a cylindrical shape to allow the top link 10 to expand and contract, and the distal end side link portion 10b. The guide pin 10c projecting at the end is guided by a long hole 10d formed in the base end side link portion 10a in the expansion / contraction direction so that the expansion / contraction range of the top link 10 is restricted.

Further, reference numeral 15 denotes a tilling depth sensor (potentiometer) arranged at the rear portion of the traveling machine body 1. The detecting arm 15a of the tilling depth sensor 15 is originally a rear cover (tilting depth) of the rotary working machine. However, when a pulling work machine such as the multiple plow 3 is connected, it is connected to the guide pin 10c of the top link 10 via the detection wire 16 and the detection wire 16 The base end of the outer tube 16a that guides is fixed to a position near the detection arm 15a, while the tip is fixed to a bracket 10e protruding from the base side link 10a. Therefore, the plowing depth detection sensor 15 detects the expansion / contraction of the top link 10 based on the push / pull of the detection wire 16 and inputs the detected value to the control unit 17 described later.

The control unit 17 is a control unit configured by using a so-called micro computer. This control unit 17 includes an arm angle sensor that detects the vertical swinging angle of the working depth sensor 15 and the lift arm 13 described above. 18, a position sensor 21 for detecting an operating angle of a position lever (working machine lifting operation lever) 20 arranged on the side of the driver's seat 19, a tilling depth setting volume 22 for inputting a tilling depth setting value, various types A signal is input from a work mode switching switch 23 or the like for switching the work mode, and a hydraulic control valve 25 (for lifting) of a lift cylinder 24 for hydraulically operating the lift arm 13 is determined based on a determination based on these input signals. A signal is output to the solenoid 25a, the descending solenoid 25b) and the like. That is, in the control unit 17, the draft control for raising and lowering the tow type working machine such as the multiple plows 3 in order to keep the towing resistance constant, and the raising and lowering control for the rotary working machine to keep the working depth constant. Various controls such as the automatic plowing depth control, the position control for raising and lowering the working machine to a certain height according to the operating angle of the position lever 20 when the draft control and the automatic plowing depth control are not executed are executed. Of these controls, draft control and position control will be described below.

The draft control is executed in a state where the work mode switching switch 23 is set to the “plow” position and the position lever 20 is operated to a substantially lowermost position. When the above operation is performed, the multiple plows 3 are lowered to the grounding position based on the hydraulic operation of the lift arm 13, and when the traveling vehicle body 1 starts to travel in this state, the multiple plows 3 are soiled. At this time, the plunge 3 is subjected to plowing work, but at this time, a downward moment based on its own weight and an upward moment based on the traction resistance act on the multiple plows 3, and these contradictory moments are applied. The multiple plows 3 freely rotate about the lower link connecting pin 14 as a fulcrum for balancing.

Then, the multiple plows 3 become stable at a position where both moments are balanced, but the rotational position thereof is detected by the tilling depth sensor 15 which is linked to the expansion and contraction of the top link 10. At the same time, the control unit 17 compares the set value of the plowing depth setting volume 22. Then, when the detected value and the set value match (including the dead zone), the lift arm 13 is stopped, but when the detected value is larger than the set value, the lift arm 13 is raised while the detected value is increased. If is smaller than the set value, the lift arm 13 is lowered. That is, when the actual plowing depth is larger than the set plowing depth, the traction resistance increases as compared to when the plowing depth is set, so that the multiple plows 3 rotate upward, and based on the upward turning. By detecting the deep plowing condition, the multiple plows 3 are raised. By stopping the ascending operation when the detected value and the set value match, the actual tilling depth is maintained at the set tilling depth. On the other hand, when the actual plowing depth is smaller than the set plowing depth, the traction resistance is reduced as compared to when the plowing depth is set, so that the multiple plows 3 rotate downward, and based on the downward rotation. It is designed to lower the multiple plows 3 by detecting the shallow plowing state. Then, by stopping the descending operation when the detected value and the set value match, the actual tilling depth is maintained at the set tilling depth.

On the other hand, in the position control, the detected value of the position sensor 21 and the detected value of the arm angle sensor 18 are compared with each other, and an up / down signal is output to the hydraulic control valve 25 in order to match the detected values. However, when the lift arm 13 is lifted to the upper limit position for the first time after the work is started, the lift signal is continuously output until the relief valve 26 is operated. It is becoming like this. Then, based on the fact that the lift cylinder 24 has stopped for a predetermined time, the upper limit is determined, and the detection value of the arm angle sensor 18 stored at this time is recognized as the upper limit value. Although the lift cylinder 24 is stopped at the upper limit position without being operated, after the relief valve 26 is operated, a down signal having an extremely small duty ratio (pulse width) is output. Immediately, the pressure in the lift cylinder 24, which has risen to the operating pressure of the relief valve 26, is reduced without operating the lift cylinder 24.

In the embodiment of the present invention configured as described above, when the multiple plows 3 are towed by the traveling vehicle body 1, the multiple plows 3 have a downward moment caused by their own weight and an upward moment caused by the traction resistance. However, in order to balance these opposing moments, the multiple plows 3 freely rotate about the lower link connecting pin 14 as a fulcrum. That is, since the multiple plows 3 are allowed to freely rotate based on the expansion and contraction of the top link 10, the multiple plows 3 are pulled by only the lower link 11. Therefore, it is possible to prevent a large moment due to traction resistance from acting on the airframe via the toplink 10 as in the conventional case where the multiple plows 3 are connected via the toplink 10 having a constant link length. As a result, even when a work machine having a large traction resistance such as the multiple plow 3 is towed, extremely stable work traveling is possible and, in addition, work accuracy can be remarkably improved.

Moreover, the free rotation of the multiple plows 3 is made possible by expanding and contracting the top link 10 which is an accessory part of the machine body without providing any special mechanism on the multiple plows 3 side. Since it is allowed, it is not possible to eliminate the irrationality of providing a special mechanism to all selectively connected towed work machines, but it is possible to use the existing towed work machines. Therefore, the implementation cost can be minimized.

Further, since the detection wire 16 for detecting the expansion and contraction of the top link 10 is provided between the base end position of the top link 10 and the working depth sensor 15 provided on the machine body side, The detection wire 16 is not exposed to the outside of the machine as much as when the detection wire 16 is interposed between the machine and the machine body. Therefore, troubles such as the detection wire 16 being caught can be prevented.

In addition, when a plurality of connection holes are formed in the machine-side top link connecting portion or the working machine-side top link connecting portion so that the connection position of the top link 10 can be selected, selection of the connecting position is possible. Can be done conventionally. That is, the connecting position of the top link 10 cannot be selected as in the case where a flexible mechanism for allowing the working machine to freely rotate is provided at the machine side top link connecting part or the work machine side top link connecting part. As a result, as a result, it is possible to adjust the optimal connecting position according to the working machine and further contribute to the improvement of working accuracy.

Further, in the position control of the above-described embodiment, when the relief valve 26 is operated at the upper limit position of the lift arm 13, a down signal with an extremely small duty ratio is continuously output, so the operating pressure of the relief valve 26 is reduced. The pressure in the lift cylinder 24, which has risen to, can be reduced without actually moving the lift cylinder 24. That is, it is not possible to completely eliminate the inconvenience that the smooth switching operation of the hydraulic control valve 25 is obstructed as in the case of performing the next cylinder operation while maintaining the lift cylinder 24 at a high pressure state. Be sure to prevent unnatural movements of the work equipment, such as those that actually move the lift cylinder 24 to depressurize, or to give vibrations or shocks to the machine body due to the rise and fall. You can

It should be noted that the present invention is not limited to the above-described embodiment, and the working machine to be used is not limited to the multiple plow, for example, and a towing type working machine such as a subsoiler is used. May be used.

Further, in the first embodiment, the interchange mechanism for allowing the work machine to freely rotate is provided in the top link itself. However, as in the second embodiment shown in FIGS. 10 and 11, Even when the accommodation mechanism is provided in the top-link bracket 27 on the machine body side, the same effect as that of the first embodiment can be obtained. That is, in the second embodiment, the machine-body-side connecting pin 28 of the top link 10 is supported by the elongated hole 27a formed in the top-link bracket 27 so as to be movable back and forth, and the body-side connecting pin 28 is used as a working depth sensor. It is connected to 15 to detect free rotation of the working machine.

Further, as in the third embodiment shown in FIGS. 12 and 13, it is possible to detect the actual working depth and control the working machine up and down. That is, in the third embodiment, the connecting frame 4 is provided with a ruler wheel 29 that swings up and down as the working depth changes, and the swing angle is measured by a working depth sensor (potentiometer) 30. It is configured to detect and control the working machine to move up and down based on the detection. With this product, it is possible to perform extremely accurate control of the working depth even in fields where the traction resistance does not become constant even when working at a constant working depth (soft fields, uncultivated fields, etc.). The working depth control in the example can be performed not only alone but also in combination with the draft control in the first embodiment.

Furthermore, the depressurization of the lift cylinder 24 in the position control may be performed based on the detection of a pressure sensor (not shown) that detects the pressure of the lift cylinder 24, and further, The lifting speed control of the working machine may be performed by utilizing the pressure detection of the pressure sensor. In this case, since the pressure of the lift cylinder 24 can be changed smoothly, it is possible to protect the lift cylinder 24 and also to raise and lower the working machine due to a sudden pressure change. It is possible to reliably eliminate the inconvenience of generating vibrations and shocks, and moreover, it is possible to perform optimal lifting control for various work machines with different weights.

[0020]

[Advantageous Effects] In summary, since the present invention is configured as described above, when the traveling machine body pulls the working machine through the top link and the lower link, the working machine receives a downward moment due to its own weight. , And an upward moment based on the traction resistance will act, but since the top link itself or the top link connection part on the machine side is provided with a flexible mechanism, the towed work machine will have opposite moments. In order to balance the above, the lower link connecting part will freely rotate about the fulcrum. Therefore, the work machine is towed only by the lower link without exerting a traction resistance on the top link, and as a result, when a work machine with a large traction resistance such as a multiple plow is towed. In addition, it is possible to avoid the application of an excessive moment to the machine body and significantly improve the traveling stability. However, based on the improvement of the traveling stability, the working accuracy can be significantly improved.

Moreover, since free rotation of the working machine is allowed without providing any special mechanism on the working machine side, it is special for all tow type working machines that are selectively connected. Not only is it possible to eliminate the absurdity of having a mechanism, but it also allows the use of existing towed operating machines, and as a result the implementation costs can be minimized.

[Brief description of drawings]

FIG. 1 is a side view of a tractor to which multiple plows are connected.

FIG. 2 is a side view of the main part of the same.

FIG. 3 is a perspective view showing an extended state of the top link.

FIG. 4 is a perspective view showing a reduced state of the top link.

FIG. 5 is a hydraulic circuit diagram of the tractor.

FIG. 6 is a block diagram showing a configuration of a draft control device.

FIG. 7 is a draft control flow chart.

FIG. 8 is a position control flow chart.

FIG. 9 is a timing chart showing the operation of position control.

FIG. 10 is a perspective view of a machine-side top link connecting portion showing the operation of the second embodiment (top link rearward displacement state).

FIG. 11 is a perspective view of the same showing a top link forward displacement state.

FIG. 12 is a side view of the main part of the same showing a shallowly plowed state of the third embodiment.

FIG. 13 is a side view of the main part of the same showing a deep plowing state.

[Explanation of symbols]

 1 traveling machine body 2 lifting link mechanism 3 multiple plows 10 top link 11 lower link 13 lift arm 15 tilling depth sensor 17 control section

Claims (1)

[Scope of utility model registration request] 1. A traction type is provided at a rear portion of the traveling machine body through a lower link that is actively moved up and down based on hydraulic operation of a lift arm, and a top link that is passively moved up and down as the lower link is moved up and down. In the tractor connecting the working machines, the top link itself or the top link connecting portion on the machine body side is provided with a flexible mechanism for allowing free rotation of the working machine with the lower link connecting portion on the working machine side as a fulcrum. At the same time, a draft control device for a tractor, wherein the hydraulic control valve of the lift arm is linked to a draft control means for vertically moving the lift arm so as to maintain a constant posture of the interchange mechanism.