JP3498474B2 - Tractor load control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tractor load control device. 2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Application Laid-Open No. Hei 6-141606, a rotary work machine is connected to the rear part of a machine body so as to be able to move up and down, and a rotation angle of a cover for covering the tilling part. Tillage depth control that detects the actual tillage depth value and raises and lowers the working machine to approach the actual tillage depth value to a preset set tillage value,
There has been a tractor provided with a load control for raising and lowering the work implement in order to prevent a decrease in the engine speed due to the towing load of the work implement. [0003] However, when performing the tilling work with the above tractor, the work implement is lowered to the position of the set cultivation depth value, and the tilling part is plowed into the soil to start or to start at a low speed. When the vehicle travels at, the traction load suddenly increases, and accordingly, there is a problem that the working machine suddenly rises or the engine stops. According to the present invention, a load control for raising and lowering a work machine and a plowing depth control are efficiently operated to perform a work with a good leveling property. [0004] The present invention has been configured as follows in order to solve the above-mentioned problems. That is,
The tilling work machine 1 is connected to the rear of the body so as to be able to move up and down, and the actual cultivation depth value is detected from the rotation angle of the cover 2 covering the cultivation portion, and the cultivation depth value is set to the set cultivation depth value set by the cultivation depth setting device 3. Plowing depth control for raising and lowering the work implement 1 to approach the actual plowing depth value, and determining the traction load of the work implement 1 from the rotation speed of the engine 4,
A load control that raises and lowers the work implement 1 so that the rotation speed of the engine 4 is maintained within a predetermined range; and a vehicle speed sensor 5 that detects a traveling vehicle speed of the aircraft. When the work implement 1 is lowered under the condition that the number is equal to or less than the set value and the vehicle speed is equal to or less than the set vehicle speed, the work implement 1 is held at a position slightly higher than the setting position of the tillage depth setting device 3. A load control device for a tractor, wherein the control unit 6 is provided. According to the present invention, since the tractor load control device described above is used, the vehicle speed and the engine speed are detected when the tractor is stopped or running at low speed, and the vehicle speed and the engine speed are detected. When the operator lowers the tilling work machine 1 under the conditions set together, the work machine 1 is held at a position slightly higher than the tilling set value, that is, at a position where the tilling load is small. Accordingly, the tillage load is not rapidly increased, and the accompanying decrease in engine rotation can be detected, the work implement can be prevented from rising, and the engine stop can be prevented. An embodiment of the present invention will be described below. The tractor 10 has a main frame 12 integrally connecting the clutch housing, a transmission case, a rear transmission case, and the like from the engine 4 mounted inside the hood 11 as a rigid main body portion of the vehicle body. A transmission (not shown) is provided. Front wheels 17 are provided on the front left and right of the main frame 12, and rear wheels 18 are also provided on the rear left and right of the main frame 12.
8 and 18 are configured to appropriately reduce and transmit the rotational power of the engine 4 via the transmission. Main frame 12
From the center to the upper rear, there are provided floors 19 and fenders 20 connected to the rear end and covering the rear wheel 18 from the front to the upper. A meter panel 21 is provided on the back of the hood 11. An accelerator pedal 22 is provided below the meter panel 21. A handle 23 projects from the rear of the meter panel 21, and the front wheels 17 are steered by turning the handle 23. An accelerator lever 16 and a work implement elevating one-touch lever 15 are provided below the handle 23. A work implement lifting switch 24 is provided at the base of the work implement elevation one-touch lever 15, and is connected to a control unit 6 described later, and the work implement 1 is moved up and down within a set height range each time the switch is turned on. Has become. A cockpit 27 is provided between the fenders 20 behind the handle 23, and the control unit 6 is provided below the cockpit 27.
A speed change lever for traveling and a work implement elevating lever 28 protrude from the side of the cockpit 27, and a tillage depth setting device 3 is provided near the lever guide. The cultivation depth setting device 3 is from level 1 (shallow cultivation depth) to level 8 (cultural depth)
Up to tillage setting value is configured to be selectable in dial type,
In accordance with this level, the lift arms 34 to be described later rotate to determine the working position of the working machine 1. In addition, a potentiometer 29 is provided at the rotation base of the work machine elevating lever 28 to detect the rotation angle. From the back of the main frame 12 of the tractor 10,
A PTO shaft 30 is protruded, and a cylinder case 32 is provided on the rear upper surface of the main frame 12. Supplying or discharging hydraulic oil into or from a main cylinder 33 built in the PTO shaft 30 causes the cylinder case 32 to be positioned on the left and right sides of the cylinder case 32. The lift arms 34 that are pivotally supported are vertically rotated. A lift arm angle sensor 45 for detecting this angle is provided at a pivot portion of the lift arm 34. The expansion and contraction of the piston of the main cylinder 33 is performed by energizing the switching control valve 44 of the control unit 6, and the working machine 1 is moved up and down via the lift arms 34. [0008] The tilling work machine 1 (hereinafter referred to as the work machine 1) is provided via the three-point link mechanism and performs ground work while being pulled by a tractor 10. This work machine 1
It is composed of a tilling part, a cover part surrounding the tilling part, and the like. The tilling unit takes out the rotational power of the engine 4 from the PTO shaft 30, and transmits the transmission shaft 35 and the work implement 1
And transmitted to the rotating shaft 37 through the transmission mechanism of
Are driven to rotate to grind, agitate, and plow the soil in the field. In addition, the cover portion includes a rotary cover 39 that rotates around the rotation shaft 37 while covering the upper portion of the tillage portion,
The rear cover 2 and the like are rotatably mounted on the rear part of the rotary cover 39. The rear cover 2
One end is attached to the hitch and the other end is pressed downward by an elastic pressing body 41 attached to the rear cover 2. A rear cover angle sensor 42 for detecting a rotation angle of the rear cover 2 is provided on the rear upper surface of the rotary cover 39.
Is provided, and the rear cover angle sensor 42 transmits the detected value to the control unit 6. The vehicle speed sensor 5 is a ground-type Doppler sensor, and is provided at the front of the main frame 12. The sensor 5 transmits an ultrasonic wave toward the field, detects the reflected wave, and detects the traveling speed of the tractor 10. The vehicle speed sensor 5 includes front wheels 17 and 17,
Alternatively, the vehicle speed may be calculated indirectly by detecting the number of rotations of the rotating shafts of the rear wheels 18, or the actual vehicle speed may be obtained by pressing the wheels on the field and detecting this rotation. Alternatively, a vehicle speed value may be set in advance in each of the gear stages in a ROM 52 described later, and this may be used as the actual vehicle speed. A rotation output shaft of the engine 4 (not shown)
A gear is mounted on the shaft, and an engine rotation sensor 31 is provided near the gear. The lifting and lowering operation of the work implement 1 of the tractor configured as described above is performed by the operator himself / herself intentionally operating the work equipment raising / lowering lever 28, detecting the operation angle with a potentiometer 29, and setting the lift arm in accordance with the angle. There is a method in which the work machine 1 is moved up and down by rotating the work machine 34, and a method in which the work machine 1 is moved up and down within a preset elevating range by turning on the work machine elevating switch 24. Further, a configuration that is linked with the turning operation, for example, a mode in which the working machine 1 that has risen at the end of the turning automatically descends according to a command from the control unit 6 may be adopted. The load control will be described. First, the control unit 6 sets the lower limit value and the upper limit change rate of the engine speed in accordance with the tillage depth setting value when the work implement 1 is at the non-working position. The control unit 6 is configured to periodically detect the engine speed and calculate the rate of change within a certain time. Then, when an engine speed lower than the lower limit value of the engine speed is detected, the work implement rising output is performed for a certain period of time, and the work implement 1 is raised. Further, when the calculated change rate detects a change rate larger than the set change rate, the work implement 1 is configured to output a rising output for a certain period of time and operate the work implement upward. During this time, the plowing depth control is interrupted. That is, the condition that the work implement 1 rises by the load control is that the traction load gradually rises and the engine speed falls and falls below the lower limit value, or the traction load increases rapidly and the engine load drops sharply. However, this is one of the cases where the detected change rate of the engine speed is larger than the set change rate. By raising the work machine 1, the actual plowing depth value becomes shallow, the work load is reduced, and engine stop and vehicle speed reduction can be suppressed. [0013] Explaining the plowing depth control,
The set plow value is set by the plow depth setting device 3 provided on the side of the cockpit 27. The control unit 6 detects the angle of the rear cover angle sensor 42 as an actual tillage depth value, and moves up and down the lift arm 34 when it goes out of a dead zone in the tillage depth control,
It is configured to operate so that the actual plowing depth value matches the set plowing depth value. Thus, the work can always be performed at a constant actual plowing depth even if there are irregularities in the field. The control unit 6 has a built-in RO as shown in FIG.
Microcomputer 51 having M, ROM 52
, A RAM 57, a timer clock 55, an input interface 53, and an output interface 54. The input interface 53 includes a work implement lifting switch 24, a working depth setting device 3, and a work implement elevation lever 28.
The potentiometer 29, the engine rotation sensor 31, the rear cover angle sensor 42, the vehicle speed sensor 5, and the lift arm angle sensor 45 are connected, and the output interface 54 is connected to the main cylinder 33 at the end. And descending solenoid 4
4b is connected. The working machine holding height corresponding to the tillage depth set value shown in the graph of FIG. 5 is stored in the ROM 52. In the holding position, the difference between the lift arm angle (L1 line) corresponding to the set till depth value and the lift arm angle (L2 line) during holding is increased as the set till depth value increases. The holding position is set to be larger, and the holding position is closer to the set value of the plowing depth as the vehicle speed is higher. As another example, when the target engine speed is high, the holding position may be close to the set till depth value, and when the engine speed is low, the holding position may be far from the set till depth value. The flow of control according to the present invention will be described with reference to the flowchart of FIG. 1. First, in step 1, the control unit 6 determines whether the work implement 1 is in the work position or in the non-work position by the lift arm. It is determined by the angle sensor 45.
When the working machine 1 is in the non-working position, in step 2,
The lower limit value of the engine speed and the set change rate according to the tillage depth setting value are set. In step 3, the operator lowers the working machine 1 by the working machine elevating switch 24 or the working machine elevating lever 28. Then, when this lowering operation is detected, in step 4,
The vehicle speed is detected by the vehicle speed sensor 5 and it is determined whether or not the vehicle speed is equal to or lower than a predetermined value. In step 5, the engine speed is detected by the engine rotation sensor 31 and it is determined whether or not the engine speed is lower than the predetermined value. Step 5
Is not cleared, the work implement lowering output is made in step 6, and the work implement 1 is lowered to the lift arm angle (L1 line) corresponding to the plowing depth set value shown in the graph of FIG. Then, in step 7, the tillage depth control and the load control are started. When the steps 4 and 5 are cleared, in other words, when the vehicle speed is lower than a certain value and the engine speed is also lower than a certain value, the output of the work implement 1 is lowered in step 8, but in step 9 At the holding position corresponding to the tillage depth set value shown in the graph of FIG.
(The line of ...), the descent is stopped. Then, at step 10, the vehicle speed value and the engine speed are detected again, and when they are cleared, the process proceeds to step 11 to start the tillage depth control and the load control. Then, in step 12, the plowing depth control and the load control are continued until an artificial ascent operation by the worker is detected. When the ascent of the work implement 1 is detected, the process proceeds to step 13 where the work implement 1 is elevated to return. Become. As described above, at the start of work or at the time of turning, when the vehicle speed and the engine speed are lower than a certain value and there is a descending output, the work machine 1 is held at a position slightly higher than the set plowing depth. As a result, the work implement 1 is temporarily stopped at a position where the engine load is not applied, and when the vehicle speed increases or the engine speed is increased, the work implement 1 is switched to the tillage depth control, and the work implement 1 is raised and lowered according to the set plowing depth value. Therefore, the conventional work machine 1 is directly lowered to the position corresponding to the set till depth value, and a sudden work load is applied, thereby preventing the engine from being stopped by the load control. The load control and tillage depth control of the present invention will be described in detail with reference to a time chart. After the rising output of the work machine 1 by the load control, conventionally, as shown in FIG. 9, the engine speed is returned to the original speed and then switched to the plowing depth control, and the descending output according to the plowing depth set value is output. Configuration. That is, when the rate of change of the engine speed (rotational speed difference ΔE ₁ within a certain time T ₁ ) is larger than the set rate of change,
The tillage depth control is interrupted, the rise by the load control is output for a certain period of time, and the tillage depth control is continued after the engine speed is restored. Similarly, when the engine speed is lower than the set lower limit of the engine speed, the rising output of the work implement 1 is output for a certain period of time, and when the engine speed exceeds the lower limit, the plowing depth control is continued. Was. For this reason, after the work machine 1 is lifted by the load control, it is not possible to maintain the actual plowing depth according to the set plowing depth while the work machine 1 is being raised, and it is desired to lower the work machine 1 as quickly as possible. I was Also, there is a difference in mechanical response between the raising and lowering operation of the work implement 1 and the detection of the actual return of the engine speed. During this time, although the engine load is reduced, actual plowing is performed. There was a problem that the depth could not be maintained at the set tillage depth. In order to solve such a problem, the control unit 6 is configured to continuously store the result of the detection of the engine speed in a storage device such as the RAM 57, so that a lower limit value of the engine speed, Alternatively, the engine speed at the time when the output of the work implement 1 is increased according to the condition of the dead zone change rate is stored, and further, the decrease of the engine speed after the output of the work implement is output is continuously detected to perform the increase output. Based on the engine speed at the time of the start, the output of the work implement is lowered before returning to the original engine speed. For example, as shown at a point A in FIG. 6, when the set value h is provided and the change rate exceeding the set change rate is detected and the work implement 1 rises, the engine speed returns to the original speed. Before the wear, that is, when the rotation speed is returned to the value obtained by subtracting the set value h, the control is switched to the plowing depth control, and the work implement descending output according to the set plowing depth value is performed. Further, even if the output of the work implement 1 falls below the lower limit of the engine speed as shown at point B and the output of the work implement 1 is increased, the system switches to the plowing depth control when the speed returns to the speed obtained by subtracting the set value h from the lower limit. It has become. As a result, the difference between the actual tillage depth and the set tillage depth value can be made to match as quickly as possible as compared with the conventional technique, and it is possible to perform an operation with less variation in tillage depth.
Further, as another embodiment, as shown in FIG. 7, based on the engine speed at the time of performing the ascending output by the load control, it is detected that the engine speed has returned to the recovery, and the mode is switched to the plowing depth control. A configuration may be employed in which the output of lowering of the working machine 1 according to the set till depth value is performed. Thereby, the difference between the actual tillage depth and the set tillage depth can be made to match as quickly as possible as compared with the embodiment of FIG. Has become. As another embodiment, as shown in FIG. 8, when the set value H is provided and the output of the working machine 1 is increased under the conditions of the lower limit value of the engine rotation and the set change rate, the increased output is Before the engine speed starts returning to the normal value, the set value H is further deviated from the original reference value.
Detected that the engine speed decreased to
Work machine 1 that switches to the above-mentioned tillage depth control and that corresponds to the set tillage depth value
May be configured to perform the falling output. This allows
Compared to the detection of the engine speed and the actual operation of the lift arm 34 to detect this result, and further lowering of the work implement 1, the actual cultivation depth of the work implement 1 is quickly set to the set cultivation depth value. It became possible to match. Further, in order to prevent a hunting phenomenon in which the work implement 1 alternately goes up and down by the load control and the plowing depth control, the descent output for a certain period of time by the plowing control is determined by the count of the timer clock 55. It is good also as a structure which restrains the working machine rise due to. The tillage depth control will be described. Conventionally, the detection of the tillage depth based on the rotation angle of the rear cover 2 is based on local clods and grass entanglement, and the work implement 1 is continuously raised and lowered alternately due to the flapping of the rear cover 2. Hunting occurred, and the tillage depth was not constant. In order to solve such a problem, the control unit 6 continuously stores the actual tillage depth value by the rear cover angle sensor 42, and removes the dead zone for raising and lowering the working machine by the rotation angle of the rear cover 2. If the signal detection state outside the dead zone continues for a certain period of time or the signal detection state outside the dead band does not interrupt more than a certain number of times within a certain period, the work equipment 1 is not configured to be output. Further, since the fluttering of the rear cover 2 becomes more frequent in substantially proportion to the vehicle speed of the tractor 1, the output check time of the fixed time is changed in accordance with the vehicle speed. That is, the output check time is set longer as the vehicle speed is higher, and the output check time is set shorter as the vehicle speed is lower. Also, since the hunting of the rear cover 2 occurs more frequently as the cultivation depth becomes shallower, the predetermined time is configured to change according to the set cultivation depth value. That is, the output restraint time is set to be longer as the tillage depth set value is shallower, and the output restraint time is set shorter as the tillage depth set value is deeper. Accordingly, even if the rotation of the rear cover 2 due to the local entanglement of soil or grass is detected, the lifting output of the work machine 1 is restrained, and the conventional hunting-like vertical movement is suppressed, and stable plowing is performed. The depth is secured. In the claims, the reference numerals corresponding to the configuration of the embodiment are attached, but the present invention is not limited to the configuration by the reference numeral.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flowchart. FIG. 2 is an overall side view of the tractor. FIG. 3 is a top view near the handle of the tractor. FIG. 4 is a block diagram. FIG. 5 is a graph showing a tillage depth set value and a holding position. FIG. 6 is a time chart A showing a change in engine speed. FIG. 7 is a time chart B showing a change in engine speed. FIG. 8 is a time chart C showing a change in engine speed. FIG. 9 is a time chart showing a conventional variation in engine speed. [Description of Signs] 1 Plowing work machine 2 Cover 3 Tillage depth setting device 4 Engine 5 Vehicle speed sensor 6 Control unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-141608 (JP, A) JP-A-7-246003 (JP, A) JP-A-63-133903 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) A01B 63/111 A01B 63/10

Claims (1)

(57) [Claims] [Claim 1] A tilling work machine 1 is connected to the rear part of a body so as to be able to move up and down freely, and an actual tilling depth value is detected from a rotation angle of a cover 2 covering the cultivating portion. Tillage depth control for raising and lowering the work implement 1 to approach the actual plowing depth value to the set plowing depth value set by the depth setting device 3, and determining the traction load of the work implement 1 from the rotation speed of the engine 4. A load control for raising and lowering the work implement 1 so that the rotation speed of the engine 4 is maintained within a predetermined range, a vehicle speed sensor 5 for detecting a traveling vehicle speed of the aircraft is provided. When the work implement 1 is lowered under the condition that the rotation speed is equal to or less than the set value and the vehicle speed is equal to or less than the set vehicle speed, the work implement 1 is held at a position slightly higher than the set position of the plow depth setting device 3. A load control device for a tractor, comprising: .