JP2008011704A - Lifting controller for implement of tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve accuracy in draft sensing of a mixed lifting controller. <P>SOLUTION: The lift controlling means is constituted to control lifting of the soil working implement (2) in such a way that a mixed value locates in a dead zone set by a position setting means (12), wherein the mixed value is obtained by respectively multiplying weight constants set by a draft ratio setting means (20) by a difference between detected traction load value by the draft detecting means (8) and the predetermined objective traction load value and a difference between detected position value and the predetermined position value, and adding obtained values, and the dead zone is constituted as variable according to the weight constant set by the draft ratio setting means (20). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a work implement lifting control device for a tractor provided with a ground work implement such as a plow.

Conventionally, the actual traction load detection value obtained with the draft detector and the working position detection value obtained with the position detector are each assigned a weighting factor with the weighting ratio set by the draft ratio setting device, and multiplied by the weighting factor. Based on the fluctuation of the calculated value, the tractor body A mix raising / lowering control device configured to raise and lower a working device connected to the machine is known (Patent Document 1).
JP 9-187110 A

By the way, in the mix up / down control, a dead zone having a predetermined width is provided in order to maintain the work position set value.
However, this dead zone is set to a predetermined width or can be arbitrarily changed to be sensitive or insensitive, and there is no consideration related to the weighting coefficient set by the draft setting means, and in particular the sensitivity by the draft sensor. When it becomes insensitive, the influence is great.

  An object of the present invention is to maintain good sensitivity by a draft sensor.

  In view of the above, the invention according to claim 1 detects the traction load of the ground work machine (2) by connecting the ground work machine (2) to the rear part of the tractor (1) through a lifting link so as to be lifted and lowered. A draft detecting means (8) and a position detecting means (13) for detecting the operating angle of the lift arm connected to the lift link are provided, and the traction load value detected in advance by the draft detecting means (8) and the traction target set in advance are provided. A value obtained by multiplying the difference between the value and the difference between the detected position value and the preset position setting value by the weight constant set by the draft ratio setting means (20) is added to obtain a mix value. Ascending / descending control means is configured to elevate and lower the ground work machine (2) so as to fall within the dead zone with respect to the value set by the position setting means (12). The dead zone is formed by the draft ratio setting means (20). The structure of the working machine lifting control device of a tractor, characterized by being configured so as to change according to a constant the weight constant.

    When configured as described above, the difference between the detected traction load value (DR) by the draft detection means (8) and the preset traction target value (dr), and the detected position value (LF) of the position means (13) A value obtained by multiplying the difference from the preset position setting value (CL) by the weight constant (MX or (1-MX)) set by the draft ratio setting means (20), respectively, is added to the mix value (DX). The ground work machine (2) is moved up and down so that the deviation (DX-CL) falls within the dead band (± B) so that the mix value (DX) matches the set value (CL) of the position setting means (12). Control. The weight constant (MX) is changed as the draft ratio setting means (20) is operated in a predetermined manner, and the plowing depth becomes deep on the side where the traction target value is increased, which is effective for heavy soil quality. On the other hand, the weight constant exhibits the reverse characteristics as the operation is reversed, and the smaller the towing target value, the shallower the cultivation depth, which is suitable for relatively light soil quality. The operator appropriately sets the draft ratio setting means (20) while considering the soil quality.

  The work implement lifting control is executed so as to eliminate the deviation (DX-CL) between the mix value and the set value by the position setting means, that is, to match the mix value DX and the position lever value CL. When a deviation exceeding a preset dead band ± B occurs, a drive current corresponding to the deviation is selected to excite the rising solenoid 23 or the lowering solenoid 24 of the hydraulic valve. The dead band ± B is set in advance. It is changed according to the weight constant set by the draft ratio setting means (20), and the dead band ± B is set to be narrower as the weight constant (MX) is smaller.

  According to the first aspect of the present invention, as the pull target value becomes smaller, the width of the dead zone becomes narrower, the control operation becomes more sensitive, and the control accuracy can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A ground work machine 2 is connected to the rear part of the tractor 1 body so as to be movable up and down. The ground work machine 2 is a plow and will be described as a plow work machine 2 below.

  The plow work machine 2 is connected and supported at the rear part of the tractor 1 by a three-point link mechanism 5 including a pair of lower left and right lower links 3 and 3 and an upper top link 4. Further, the lift arm 6 rotatably provided at the rear part of the tractor 1 and the intermediate part of the lower links 3 and 3 are connected by the lift rod 7, and the plow working machine 2 is moved up and down by the rotation of the lift arm 6. It is configured as possible.

  The support mechanism of the plow work machine 2 is pushed backward when the plow work machine 2 receives a traction load during the uplifting work and the soil enters the tip of the plow work machine 2, and the tip portions of the lower links 3, 3 The lower side retreats with the mounting part (pivoting part) with the tractor 1 body as a fulcrum, and conversely, the upper top link 4 side is pressed forward. A draft detecting means 8 for detecting a traction load is provided in the tractor 1 side connecting portion of the lower link 3 or the tractor 1 side connecting portion of the top link 4, and is detected and output to the control unit C described later.

  Next, the position setting means will be described. FIG. 2 shows the vicinity of the driver's seat of the tractor, and a work machine ascent / descent position lever 11 is provided on the front end side of the armrest 10 so as to be operated forward and backward. A position setting means 12 comprising a potentiometer is provided at the rotation base of the position lever 11, and the set value is output to the control unit C. On the other hand, a lift arm angle sensor 13 for detecting the rotation angle of the lift arm 6 is provided at the base of the lift arm 6. This lift arm angle sensor 13 constitutes a position detecting means for detecting a work machine position with respect to one tractor body.

  The armrest 10 is provided with a seesaw-type work implement raising / lowering switch 14, which lowers the work implement to the set position of the position lever 11 when operated to the front side, and conversely raises the work implement to the maximum raised position when operated rearward. The configuration is to let

  Various switches and levers are disposed on the operation panel 15 adjacent to the armrest 10. If the switches related to the working machine ascending / descending are shown, reference numeral 20 denotes a setting dial as draft ratio setting means, which sets weight constants for setting values of drafts and positions in the mix control described later. Reference numeral 21 denotes a lifting adjustment dial which can set the lifting height of the work implement. Reference numeral 22 denotes an inclination adjustment dial which can control the right and left inclination of the work implement.

  The control unit C receives inputs from the draft detection means 8, position detection means (lift arm angle sensor) 13, position setting means 12, draft ratio setting means 20, raising adjustment dial 21, and inclination adjustment dial 22, and lift arm 6 is output as a hydraulic valve raising command or a raising command.

Next, mix control in which draft control and position control are combined will be described.
The plow work machine 2 is controlled to be lifted and lowered based on a predetermined draft setting value while being lowered to the work position set by the position setting means 12. That is, the draft ratio is set based on the difference between the detected traction load value DR by the draft detecting means 8 and the preset traction target value dr and the difference between the detected position value LF of the position means 13 and the preset position set value CL. A value obtained by multiplying the weight constant MX or (1-MX) set by the means 20 is added to obtain a mix value DX. In order to make this mix value DX coincide with the set value CL of the position lever 11, a deviation (DX− The plow work machine 2 is lifted and lowered so that CL) falls within the dead zone. The mix value DX is calculated by the following equation.

DX = CL + MX / 100 x (DR-CL) + (1-MX / 100) x (LF-CL)
= MX / 100 x DR + (1-MX / 100) x LF
Here, MX takes a value from 0 to 100, and the MX value becomes closer to “100” as the setting dial 20 as the draft ratio setting means is turned to the right. The plowing depth is deep and effective for heavy soils. On the other hand, the MX value approaches "0" as it is turned to the left, and the tilling depth becomes shallow, which is suitable for relatively light soil quality. The operator appropriately sets the setting dial 20 in consideration of soil quality.

  In order to eliminate the deviation (DX-CL), that is, in order to make the mix value DX and the position lever value CL coincide with each other, the work implement elevating control is executed. Specifically, when a deviation exceeding a preset dead band ± B occurs, a drive current corresponding to the deviation is selected to excite the ascending solenoid 23 or the descending solenoid 24 of the hydraulic valve (steps 104 and 105 in FIG. 4). ).

  The dead zone ± B is set in advance (step 102), but is changed according to the weight constant set by the draft ratio setting means 20. That is, the dead band ± B is set to be narrower as the weight constant MX is smaller. With this configuration, the dead zone becomes narrower as the draft ratio becomes smaller, and the control operation becomes more sensitive, thereby improving the control accuracy (FIG. 5).

  FIG. 6 relates to the improvement of the safety of the above mix control. When the position lever 11 is in the range where the plow working machine 2 is raised to the non-working posture, the position is not increased due to the detection of the draft. When the lever 11 is in the vicinity of the raised position (step 203), the above-mentioned problem can be solved by setting the weight constant MX to “0” corresponding to position control (step 204).

  Further, when the plow work machine 2 is in the ascending mode (step 205), the weight constant MX is set to “0” as described above, so that the position control is not performed and the elevator does not unexpectedly move up and down.

  FIG. 7 shows a tractor mission. The transmission mechanism includes a forward / reverse switching device having forward and reverse gears 34 and 35 from the engine 33, and a first speed gear having four-speed gears such as a first gear, a second gear, a third gear, and a fourth gear. A main transmission 36, a second main transmission 37 having high and low two-stage transmission gears such as a Hi-speed gear, and a Lo-speed gear; and three-stage transmission gears such as auxiliary transmission gears 42, 43, and 45; The rear wheel 2 is transmitted in conjunction with the rear differential mechanism 46 through a sub-transmission 38 having a gear 44 and switching the sub-shift to high speed H, medium speed M, low speed L, and neutral N.

In addition, the auxiliary transmission transmits the front wheels 31 in conjunction with a four-wheel drive switching device capable of switching between the two-wheel drive / four-wheel drive gear 47 and the double speed four-wheel drive gear 48 and the front differential gear 49.
The engine 33 is configured to transmit a PTO shaft 52 via a PTO transmission clutch 51 through a four-stage PTO transmission 51 through a PTO transmission clutch 50.

  If the arrangement along the transmission direction of the forward / reverse switching device, the first main transmission 36, the second main transmission 37, the auxiliary transmission 38, and the like is set to the series direction, the forward movement in each of these devices. The gear 34 and the reverse gear 35 are configured in a parallel arrangement. The forward gear 34 and the reverse gear 35 of the forward / reverse switching device have front and reverse clutches 53 and 54 in the form of multiple friction plates, and before this, the reverse clutches 53 and 54 are pressed against each other by hydraulic pressure from a hydraulic circuit (hydraulic pressure). By moving the forward clutch 53 or the reverse clutch 54, the forward gear 34 or the reverse gear 35 can be rotated. These forward and reverse clutches 53 and 54 are selectively operated to switch between forward transmission and reverse transmission.

  The first main transmission 36 has the above-mentioned friction multi-plate type first-speed clutch 55 to fourth-speed clutch 58 in each of the first-speed gears to the fourth-speed gears. The clutch 55 and the fourth-speed clutch 58 are turned on and off, and the first-speed gear, the second-speed gear, the third-speed gear, or the fourth-speed gear is selected and interlocked to form a parallel arrangement. Similarly, the second main transmission 37 also has the Hi clutch 50 of the same form in the Hi speed gear 40 and the Lo clutch 59 in the Lo speed gear 41, which is turned on and off by a hydraulic clutch pack. It is configured. Each sub-transmission gear 42, 43, 45 of the sub-transmission device has a clutch ring 61, 62 in the form of a dog clutch, and is configured to move forward and backward by a shifter operation.

  In the tractor 1 having the transmission structure as described above, when the auxiliary transmission is put in the high speed H that can be assumed to be on the road, the weight constant MX is set to “0” corresponding to position control. If comprised in this way, the situation where a working machine raises / lowers by the load detection of the draft detection means 8 during road driving can be avoided.

  8 to 10, during the setting operation based on the draft ratio setting means 20, an alarm such as a buzzer 65 is issued every time the weight constant MX changes. If comprised in this way, confirmation of the present setting position will become easy and grasping | ascertainment of the setting position in the last work will also become easy. Further, if a means for storing the previous set value is provided and an alarm is issued when operated at that position, the previous setting can be referred to and the set position can be easily found (FIG. 9). Note that the storage of the previous setting is executed only when traveling for a predetermined time or more is involved. With this configuration, unnecessary storage data need not be accumulated.

  Next, the penetration control will be described. The plowing control is a control for generating and lowering the plow work machine 2 by generating a maximum lowered flow rate. In the example shown in FIG. 10, when the draft ratio dial 20 is in the draft area (step 402), that is, when MX ≠ 0, after the work machine is lifted in the lift mode, a “lowering” operation is performed with the work machine lift switch 14. When it is performed, the above-described scavenging control is executed (steps 403 to 405). Note that the work machine lift in the lift mode refers to the control by the work machine lift switch 14, the work machine lift controlled in conjunction with turning, and the reverse work interlock lift. If comprised as mentioned above, since draft control will be restrained, the operation | work start can be started appropriately, without the penetration distance becoming long.

  FIG. 12 shows further improvement of the plowing control. After the plowing control is started, when the operator raises the work implement, the predetermined time T (for example, 750 msec) is lowered and output at the maximum flow rate. After the elapse of time, the output is lowered at the maximum flow rate until there is a work implement ascent output request, and the plow control is immediately stopped when there is a work implement ascent output request. Accordingly, since the predetermined time T can be forcibly lowered at the maximum flow rate, the penetration distance can be shortened.

  In the above-described embodiment, since the draft setting value is left to the operation amount of the draft ratio setting dial 20, the traction target value dr is substantially determined by the weight constant, but this traction target value dr is arbitrarily set. You may comprise so that it can set to. That is, the draft ratio setting dial 20 is configured as a double ring so that the inner and outer rings 20a and 20b can be rotated integrally and the traction target value dr is preferentially set by rotating the outer ring 20b independently. It is good also as a structure which can correct | amend to. With this configuration, the traction target value is unclear only by the setting operation of the draft ratio setting dial 20, but becomes clearer by prioritized setting.

  Reference numerals 66 and 67 are display lamps provided in the vicinity of the draft ratio setting dial 20, and are lit along the timing at which the elevation control is activated based on the traction load. Therefore, the operator can detect the sensitivity of the rising operation output by checking the blinking interval of the display lamp 66, and can detect the sensitivity of the descending operation output when the display lamp 67 flashes. The outer ring 20b can be adjusted by setting the lamps 66 and 67.

  In the case of the configuration of the draft ratio setting dials 20a and 20b having the inner and outer ring configurations, the resetting is performed when the work is completed, and the positional deviation between the inner ring 20a and the outer ring 20 is eliminated at the start of the next work and integrated. The traction target value dr correction process is in a reset state.

  In FIG. 2, the draft ratio setting dial 20 is arranged on the operation panel 15. However, by arranging the draft ratio setting dial 20 on the foremost side of the slope, the operator can look forward while facing the front. Thus, there is an effect that it is easy to reach the dial 20 at the front end.

Overall side view Cab interior control panel perspective view Control block diagram flowchart Graph showing an example of dead band-weight constant relationship flowchart Transmission mechanism diagram flowchart flowchart flowchart flowchart flowchart Perspective view showing another example of draft ratio setting dial

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tractor 2 Ground working machine 8 Draft detection means 12 Position setting means 13 Position detection means 20 Draft ratio setting means

Claims (1)

The tractor (1) is connected to the ground work machine (2) via a lift link at the rear of the tractor so as to be lifted and provided with a draft detection means (8) for detecting the traction load of the ground work machine (2). Position detection means (13) for detecting the operating angle of the lift arm to be connected is provided, and the difference between the traction load value detected by the draft detection means (8) and the preset traction target value, and the detection position value are preset. A value obtained by multiplying the difference from the position setting value by the weight constant set by the draft ratio setting means (20) is added to obtain a mix value. This mix value is compared with the value set by the position setting means (12). Ascending and descending control means for raising and lowering the ground work machine (2) so as to fall within the dead zone is configured, and the dead zone is configured to be changed according to the weight constant set by the draft ratio setting means (20). Working machine lifting control device of the tractor, characterized in that the.

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