JPH04316411A - Draft-controlling mechanism of tractor - Google Patents

Abstract

PURPOSE:To dispense with a large-sized forcing spring and a precision-work link, etc., by controlling the lift of a working machine in such a manner as to keep the load factor of an engine within a preset load factor range. CONSTITUTION:The lifting and lowering of a rotary tilling apparatus is controlled in such a manner as to keep the load factor of a working engine E within a preset load factor range of the rotary tilling apparatus R set by a load factor setting device 6. All control works can be preformed by electrical oscillation and electrical parts to improve the reliability of the control system.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a draft control mechanism for keeping the traction force of a working machine attached to a tractor constant.

0002

[Prior Art] A conventional draft control device is
It was constructed as described in Japanese Patent No. 20524. That is, the pushing force applied to the top link of the three-point link type work equipment mounting device presses the spring-biased draft sensor rod, and the draft sensor rod mechanically operates the hydraulic valve for lifting and lowering the work equipment. By switching, the draft force was controlled to be constant by raising the working machine when the traction force was large and lowering the working machine when the traction force became small.

0003

[Problems to be Solved by the Invention] The present invention, like the above-mentioned prior art, mechanically obtains the pressing force applied to the top link.
Rather than moving the draft sensor rod and switching the lift valve, the draft force is detected electronically using an electronic governor mechanism, and the working machine lift valve is switched using an electromagnetic switching valve. This makes it possible to eliminate the draft sensor rod, which was conventionally configured mechanically, and also connects the large biasing spring provided at the end of the top link on the tractor side and the switching valve to the draft sensor rod. It is configured so that complex configurations can be removed.

0004

[Means for Solving the Problems] The problems to be solved by the present invention are as described above, and next, the means for solving the problems will be explained. That is, the rotation speed detection sensor 1 and the rack position sensor 2
, an electronic governor mechanism A constituted by a rack actuator 9 and an electronic control unit G, and lift elevating solenoid valves V1 and V2.
, an accelerator lever sensor 5, a load factor setting device 6, and a lift angle sensor 3, and the detected load factor FS detected by the electronic control unit G in the working state is the set load factor set by the load factor setting device 6. This is to control the lifting and lowering of the working machine so that it falls within the setting range of F. Further, when the detected load factor FS is larger than the set load factor F, it is determined that the work state is in progress, and the detected load factor FS detected by the electronic control unit G in the work state is the set load factor set by the load factor setting device 6. This is to control the lifting and lowering of the working machine so that it falls within the set range of F. In addition, the detected load factor FS detected by the electronic control unit G in the working state is the set load factor F set by the load factor setting device 6.
When controlling the elevation of the work equipment so that it falls within the setting range, isochronous control is used to keep the engine speed constant, and in other conditions, droop control is used to change the engine speed. be. Further, the control is performed by adding the detected load factor FS and the detected traction load D. In addition, when controlling the elevation of the working machine so that the detected load factor FS detected by the electronic control unit G in the working state falls within the setting range of the set load factor F set by the load factor setting device 6, when no load Alternatively, when the load factor is small, the engine speed is lowered, and when the load is detected, it is rapidly increased.

[0005]

[Operation] Next, the operation of the present invention will be explained. In the conventional draft control mechanism, the hydraulic switching valve was controlled by a mechanical sensor mechanism installed in the top link part and a feedback mechanism composed of a link and an arm, but in the case of the present invention, , the detected load factor FS is detected by the electronic governor mechanism A, the load factor is set by the accelerator lever 14, and all signals are obtained as electronic signals to enable draft control. The electronic governor mechanism A was originally an electronic control mechanism for automatically controlling the rotation speed and load factor of the engine E as well as the fuel supply amount, but the present invention converts the electronic governor mechanism A into a draft control control component. By using it as a part, it was possible to construct a draft control with a simple configuration and completely electronic.

[0006]

[Example] Next, an example of the present invention will be described. Fig. 1 is a side view of a tractor equipped with a rotary tilling device as a working machine, Fig. 2 is a side sectional view of the electronic governor mechanism A, Fig. 3 is a side view of the electronic governor mechanism A, and Fig. 4 is a control by the electronic governor mechanism A. A drawing showing an example of a map, FIG. 5 is a hydraulic circuit diagram of a working machine elevating mechanism B equipped with lift elevating and lowering solenoid valves V1 and V2, FIG. 6 is a flowchart drawing of the draft control mechanism of a tractor of the present invention, and FIG. 7 is an electronic governor 2 is a diagram illustrating movements of detection signals and command signals between an electronic control section G of mechanism A, a lift electronic control section C, and a working machine lifting mechanism B.

The structure of a tractor will be explained with reference to FIG. An engine E is disposed inside the hood of the tractor, and an electronic governor mechanism A is attached to the side of the engine E. Further, an accelerator lever 14 through which the operator sets the rotational speed of the engine E is rotatably supported on a dashboard portion of the bonnet, and an accelerator lever sensor 5 is disposed at the base of the accelerator lever 14. The accelerator lever sensor 5 detects how much the operator has rotated the accelerator lever 14 and what rotational speed the operator desires to set. Further, a work equipment control panel 15 is provided on the side of the seat of the tractor.
A manual changeover switch 8, a load factor setting device 6 for setting the load factor of the work machine, and a work machine position setting device 7 for setting the position of the work machine during position control are arranged. Further, the rotary tilling device R mounted on the rear of the tractor is provided with a tilling depth position sensor 4 for detecting the tilling depth of the rotary tilling device R when controlling the depth of the working machine. Further, a lift angle sensor 3 is arranged at the base of the lift arm 13 for position control.

The electronic governor mechanism A will be explained with reference to FIGS. 2 and 3. The electronic governor mechanism A is attached to the side of the engine E, and has a magnetic rotating body 12 fixed to a camshaft 16 of the fuel pump. The rotation of the camshaft 16 is detected by the rotation speed detection sensor 1 of the magnetic rotating body 12 to obtain the engine rotation speed. Further, the amount of fuel supplied to the electronic governor mechanism A is adjusted by moving the fuel rack 10 left and right, and it is the rack actuator 9 that drives the fuel rack 10 based on the control command signal. Further, the rack position sensor 2 detects the position of the fuel rack 10 moved by the rack actuator 9 and detects the amount of fuel supplied. A rack bar 11 connected to a fuel rack 10 is inserted through the rack position sensor 2 and the rack actuator 9.

Next, a control curve for the engine E by the electronic governor mechanism A will be explained with reference to FIG. The engine output and shaft torque of the engine E are determined by the injection amount and injection timing of the fuel injection pump and the engine rotation speed. The fuel injection amount is adjusted by sliding the fuel rack 10 with a rack actuator 9. The injection amount is obtained by measuring the injection amount based on the position of the fuel rack 10 and the engine rotation speed. Further, the injection timing is adjusted by a timing adjustment actuator (not shown). The engine rotation speed is detected by a rotation speed detection sensor 1. By causing the electronic control unit G to rotate the accelerator lever 14 by the operator, the rotational speed is supported via the accelerator lever sensor 5. The electronic control unit G uses a microcomputer, and is provided with a program ROM that stores control programs. A data ROM is also provided that stores various data necessary for control calculations, such as speed fluctuation rate characteristics.

[0010] The data ROM contains a set value of the engine speed, which is arbitrarily set by the position of the accelerator lever 14 operated by the operator at his/her own will, and what happens to the actual engine speed (actual value) depending on the load. These speed fluctuation rate characteristics are stored in the form of arithmetic expressions or numerical tables for each different type of work. Regarding the speed fluctuation rate, it recognizes the set value and actual value of the period rotation speed, then recognizes the mode set by the operator, and calculates the target rack position to be set according to the droop rate map according to the mode. . A signal for changing the actual rack position to the corrected target rack position is sent to the rack actuator 9, and the fuel rack 10 is automatically adjusted and operated within a predetermined speed fluctuation rate range. Normally, in order to recognize a predetermined speed fluctuation, the fuel rack 10 is controlled and the shaft torque changes according to the droop control map d in Fig. 4, but the speed fluctuation rate characteristics are selected depending on the mode of the work content. When constant speed operation is required, constant speed operation is performed in accordance with isochronous control map i to increase or decrease fuel consumption and keep the load factor constant. In addition, during isochronous control, especially in special work, when the load increases and the shaft torque is close to the maximum, reverse droop is used to prevent engine stall by increasing the rotation speed and shaft torque. It is also possible to select a control map r.

FIG. 5 shows a hydraulic circuit diagram of the working machine lifting mechanism B. As shown in FIG. The lift arm 13 is moved up and down by the expansion and contraction of the hydraulic cylinder 20.
A lift angle sensor 3 is provided to detect the position of. Lift elevating solenoid valves V1 and V2 control the pressure oil to the hydraulic cylinder 20, and are comprised of an ascending electromagnetic valve V1 and a descending electromagnetic valve V2. A signal for switching between the ascending solenoid valve V1 and the descending solenoid valve V2 is transmitted from the lift electronic control section C.

The technique of claim 1 will be explained with reference to FIGS. 6 and 7. An electronic governor mechanism A composed of a rotation speed detection sensor 1, a rack position sensor 2, a rack actuator 9, and an electronic control section G, and a lift lifting solenoid valve V1 and V
2, an accelerator lever sensor 5, a load factor setting device 6,
Equipped with a lift angle sensor 3, the electronic control unit G
This is a technique for controlling the elevation of the working machine so that the detected load factor FS detected by the above method falls within the setting range of the set load factor F set by the load factor setting device 6. As shown in FIG. 7, signals are exchanged between the electronic control unit G of the electronic governor mechanism A and the electronic lift control unit C, and signals are also exchanged between the electronic lift control unit C and the work equipment lifting mechanism B. being communicated. The essential part of the present invention is that the signal from the electronic governor mechanism A can be used as a control signal for the working machine lifting mechanism B. That is, the electronic governor mechanism A and the work implement lifting mechanism B are connected via the lift electronic control section C.

Next, the process will be explained along the flowchart shown in FIG. Next to "Start" of control, "Initial settings"
I do. Next, turn off the ascending solenoid valve V1 and descending solenoid valve V2.
F”. Next, perform a "sensor check". Next, it is determined whether the check result is OK, and if the answer is NO, an alarm is sounded. If "OK", the automatic/manual changeover switch 8 determines whether it is "automatic/manual". If "manual" is selected, position control is performed. If it is "automatic", the "detection load factor FS" is read. Next, it is determined whether the rotary tiller R is in a "working state". If it is not in the working state, it moves to position control. If it is in the working state, "read the set load factor F". Next, "reading the dead zone width H" is performed. Then, the value of "HD.HS" is calculated by increasing or decreasing the dead zone width H to the detected load factor FS. Next, it is determined whether "F>HD", and "F>HD" is determined.
”, “turn on the rising solenoid valve V1”. “F>H
D", the ascending solenoid valve V1 is turned OFF. next"
It is determined whether "F<HS" and if "F<HS", the descending solenoid valve V2 is turned on. Further, if "F<HS" is not satisfied, the lowering solenoid valve V2 is turned off. If "HD<F<HS",
Both the ascending solenoid valve V1 and the descending solenoid valve V2 are turned OFF.

Next, the technique of claim 2 will be explained with reference to a flowchart shown in FIG. 8 for determining whether the control circuit is in a working state or a non-working state in order to turn it on and off. That is, when the detected load factor FS is larger than the set load factor F, it is determined that the rotary tiller R is in a working state, and the control according to claim 1 is started. That is, in the flowchart of FIG. 6, the flowchart portion from "reading detected load factor FS" to "reading set load factor F" is shown in FIG.
It was changed as follows. That is, first read the "detected load factor FS of engine E", then "read the set load factor F of engine E", then judge whether "FS>F" is true, and then check whether "FS>F" is not true. If so, it is determined that it is in a non-working state, and the process moves to position control and droop control. If "FS>F", it is determined that the machine is in a working state and shifts to "draft control and isochronous control". This determination is used to determine whether the machine is in a working state or not.

Next, in the flowchart of FIG. 9 showing switching between isochronous control and droop control, claim 3
Explain the technology. That is, in the control of claim 1,
Isochronous control is performed to keep the engine rotation constant and the load factor constant, and droop control is performed in which the engine rotation changes in other conditions. In the case of this isochronous control, the fuel supply amount is varied by sliding the fuel rack 10 in order to keep the load factor and rotation speed constant. As shown in the flowchart in Figure 9, "manual/automatic" is determined, and if it is manual, position control is performed. It performs droop control. It then determines whether or not it is in a working state, and even if it is in a non-working state, it moves to position control, accepts some variation in rotational speed, and performs droop control to keep the load factor constant. If it is determined that the engine is in a "working state" with "auto" selected, it shifts to isochronous control that changes the amount of fuel supplied to keep the load factor and rotational speed constant.

Next, as shown in FIG. 10, the ground work machine load detector 19
In the flowchart of control for obtaining the detected traction load D and adding it to the detected load factor FS, and the drawing of FIG. 11 showing the state of signal communication using the ground work equipment load detector 19, Explain. That is, in the control according to the first aspect, the detected load factor FS and the detected traction load D are added to perform the control. As shown in FIG. 11, a ground work machine load detector 19 is separately provided. The ground work machine load detector 19 has an electrical load detector interposed in the top link part of the three-point link and the drawbar hitch part, and the ground work machine load detector 19 outputs an electric signal as an electric signal. This is to obtain the traction load. Then, the moving average of the detected traction load D obtained from the ground work machine load detector 19 is calculated, and the average calculated value DM of the detected traction load D is calculated. Then, the average calculation value DM and the detected load factor FS are added to obtain the detected load factor FS'. And the detected load factor FS'
The work equipment lifting mechanism B is controlled by determining the value of increasing or decreasing the dead zone width H and the magnitude of the set load factor F.

Next, the technique of claim 5 will be explained with reference to FIG. 12, which is a flowchart for reducing the engine speed when the detected load factor FS is extremely smaller than the set load factor F or is 0. That is, in claim 1, the engine speed N is lowered when there is no load or when the load factor is small, and increases rapidly when a load is detected. That is, when the tractor turns around at the edge of the field, the detected load factor FS
is significantly smaller than the set load factor F, or the detected load factor FS becomes zero. In this case, the rotation speed of the engine E is gradually lowered, and when the detected load factor FS increases, the engine rotation speed is increased. However, the above-described reduction curve has a gentler slope than the increase curve described later.

Next, FIG. 13 shows a flowchart of control for starting and stopping control of the rotation speed or load factor by turning on and off the PTO connection/disconnection solenoid valve 18, and FIG.
This will be explained with reference to a drawing showing a signal communication state in which a TO connection/disconnection solenoid valve 18 is attached. This control technology requires that when the PTO shaft changes from a disconnected state to a connected state, the engine E
This technique lowers the rotation speed of the engine E, connects the PTO shaft, and then sets the rotation speed of the engine E to the load factor or rotation speed set by the setting means. In order to detect the connection/disconnection of the PTO shaft, the PTO connection/disconnection solenoid valve 18 is turned on.
- It performs control upon receiving the OFF command signal.

[0019]

[Effects of the Invention] Since the present invention is constructed as described above, the following effects can be achieved. In other words, since it is configured as claimed in claim 1, there is no need for a large biasing spring attached to a conventional draft control device or a precisely operated link or arm for mechanically switching the hydraulic switching valve. . Furthermore, since all controls can be performed using electrical signals and electrical components, the reliability of the control system can be improved. In addition, the electronic governor mechanism A can be used not only to control the load factor and rotation speed of the engine E but also as a component for draft control of the work equipment, so there is no need to separately prepare parts for electronic draft control. It's gone.

Furthermore, since the structure is configured as in claim 2, instead of detecting the position of the lift arm 13 by the lift angle sensor 3 and determining the working state and non-working state in the conventional draft control, the setting Since work and non-work can be detected based on the magnitude relationship between the load factor F and the detected load factor FS, this judgment can also be made electronically, improving the reliability of the entire control system. was completed.

[0021] Furthermore, since the structure is configured as in claim 3, when draft control is performed, the amount of fuel supplied is increased or decreased so that the load factor is kept constant and the engine rotational speed is constant, so that the work is performed at a constant rotational speed. Since the work is carried out under a constant load factor, it is possible to perform work with high precision. Furthermore, in the case of position control or manual control other than the case of draft control, the load factor is kept constant and the engine speed is configured to vary to some extent.

[0022] Since the structure is configured as in claim 4, the response of the engine to changes in the load of the ground work machine is slow, and conversely, the ground work machine load detector 19 provided in the work machine part is controlled too quickly and the response is slow. There are many cases where this is not possible. In the present invention, the value of the detected traction load D is taken as an average calculation value DM, and this value is added to the detected load factor FS, and this value is set as the detected load factor FS', so that the response speed is just right and the draft has a good convergence state. I was able to gain control.

[0023] With the structure as set forth in claim 5, the engine rotational speed can be maintained at a high speed when the work machine is under no load, such as when going around the edge of a field or when work is once interrupted. When the problem disappears, the rotation speed of engine E is lowered,
This made it possible to save fuel and reduce noise.

[Brief explanation of drawings]

FIG. 1 is a side view of a tractor equipped with a rotary tiller as a working machine.

FIG. 2 is a side sectional view of the electronic governor mechanism A.

FIG. 3 is a side view of the electronic governor mechanism A.

FIG. 4 is a drawing showing an example of a control map by the electronic governor mechanism A.

FIG. 5 is a hydraulic circuit diagram of a working machine lifting mechanism B that includes lift lifting and lowering solenoid valves V1 and V2.

FIG. 6 is a flow chart diagram of the draft control mechanism of the tractor according to the present invention.

FIG. 7 is a diagram illustrating movements of detection signals and command signals between the electronic control unit G of the electronic governor mechanism A, the electronic lift control unit C, and the work implement lifting mechanism B.

FIG. 8 is a flowchart for determining whether the control circuit is in a working state or a non-working state in order to turn it on and off.

FIG. 9 is a flowchart showing switching between isochronous control and droop control.

FIG. 10 is a flowchart of control for obtaining a detected traction load D by a ground work equipment load detector 19 and adding it to a detected load factor FS.

FIG. 11 is a drawing showing a state of signal communication using a ground work equipment load detector 19.

FIG. 12 is a flowchart for reducing the engine speed when the detected load factor FS is extremely smaller than the set load factor F or is zero.

FIG. 13 is a flowchart of control for starting and stopping control of the rotation speed or load factor by turning on and off the PTO connection/disconnection solenoid valve 18;

FIG. 14 is a drawing showing a signal communication state with a PTO connection/disconnection solenoid valve 18 attached.

[Explanation of symbols]

F　Setting load factor FS Detection load factor D Detection traction load DM Average calculation value A Electronic governor mechanism B Work equipment lifting mechanism C Lift electronic control section V1 Rising solenoid valve V2 Downward solenoid valve 1 Rotation speed detection sensor 2 Rack position sensor 3 Lift angle sensor 4 Plowing depth position sensor 5 Accelerator lever sensor 6 Load factor setting device 7 Work equipment position setting device 8 Automatic/manual changeover switch 9 Rack actuator 10 Fuel rack 11 Rack bar 12 Magnetic rotating body 18 PTO connection/disconnection solenoid valve 19 Ground work equipment load detector 20 Hydraulic cylinder

Claims (5)

[Claims] Claim 1: An electronic governor mechanism A constituted by a rotation speed detection sensor 1, a rack position sensor 2, a rack actuator 9, and an electronic control section G, and a lift elevation solenoid valve V1.
V2, an accelerator lever sensor 5, a load factor setting device 6, and a lift angle sensor 3, and the detected load factor FS detected by the electronic control unit G in the working state is the set load set by the load factor setting device 6. A draft control mechanism for a tractor, characterized in that a working machine is controlled to rise and fall within a set range of a rate F. 2. A draft control mechanism for a tractor, characterized in that when the detected load factor FS is larger than the set load factor F, it is determined that the work condition is present and the control according to claim 1 is performed. 3. In the control according to claim 1, isochronous control is performed to keep the engine speed constant;
A draft control mechanism for a tractor characterized by performing droop control in which the engine speed changes in other conditions. 4. A draft control mechanism for a tractor according to claim 1, wherein the draft control mechanism is configured to perform draft control by adding the detected load factor FS and the detected traction load D. 5. The draft control mechanism for a tractor according to claim 1, wherein the engine speed is lowered when there is no load or when the load factor is small, and rapidly increases when a load is detected.