JP2007000088A - Farm implement - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tractor equipped with a rotary tiller whose tillage depth can automatically be controlled without depending on the extent of the tillage depth of the rotary tiller. <P>SOLUTION: A rear cover sensor for detecting the tillage depth is disposed in the rotary tiller. A travel machine frame is equipped with a tillage depth-setting device for preliminarily setting the target tillage depth RD0 of the rotary tiller. A tillage controller is provided with ROM in which a control gain Ga has been preliminarily memorized. The tillage controller controls the driving of a lift control hydraulic cylinder to change a control gain Ga in response to control information corresponding to the target tillage depth RD0, calculate the tillage depth RD of the rotary tiller from the control gain Ga and the detection value θof the rear cover sensor, and then match the tillage depth RD with the target tillage depth RD0. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a farming machine that performs a tilling work with a rotary tiller that is mounted on a traveling machine body such as a tractor via a link mechanism so as to be able to be lifted and lowered, and more specifically, the tillage depth of the rotary tiller. The present invention relates to a structure for automatic control of tilling depth that is maintained substantially constant.

  In general, a tractor that performs tillage work includes a rotary tiller that has a front wheel and a rear wheel and is mounted on the rear part of a traveling machine body on which an engine is mounted so as to be adjustable up and down via a link mechanism, and the rotary tiller And a control means for performing automatic tilling depth control by controlling the drive of the lifting control hydraulic cylinder that lifts and lowers.

  An example of this type of tractor is disclosed in Patent Document 1. FIG. 17 is a schematic view of a tilling mode in the tractor of Patent Document 1. FIG. 17 (a) shows a case where the tilling depth is shallow, and FIG. 17 (b) shows a case where the tilling depth is deep.

  In the tractor of Patent Document 1, the rotary cultivator 504 is connected to the rear portion of the traveling machine body 501 via a link mechanism 503 so as to be adjustable up and down. The traveling machine body 501 is provided with a tilling depth setting device (not shown) for presetting a target tilling depth of the rotary tiller 504. The upper side of the rotation trajectory 505 of the tilling claw in the rotary tiller 504 is covered with a tilling cover body 506. A rear cover body 507 that can come into contact with the ground with a predetermined pressure is connected to the rear end of the tilling cover body 506 so as to be swingable in the vertical direction. A rear cover sensor 509 is provided between the tilling cover body 506 and the rear cover body 507 as a tilling depth detecting means for detecting the vertical rotation angle γ of the rear cover body 507.

  At the time of tillage work, the rear cover body 507 is grounded at a predetermined pressure, and the tillage depth rd obtained from the detected rotation angle γ of the rear cover sensor 509 is set in advance so as to be the target tillage depth set by the tillage depth setting device. Automatic control of tilling depth is executed by driving a lift control hydraulic cylinder (not shown) with a set constant control gain (value determined by characteristics of a mechanism or electric circuit for detecting tilling depth). . In other words, the tilling depth rd of the rotary tiller 504 is calculated from the detected rotation angle γ of the rear cover sensor 509 and the constant control gain, and the raising / lowering is performed so that the calculated tilling depth rd becomes the target tilling depth. The tilling depth automatic control is executed by driving the control hydraulic cylinder.

In FIG. 17, the symbol a is added to the tilling depth rd and the vertical rotation angle γ shown in (a), and the symbol b is added to the tilling depth rd and the vertical rotation angle γ shown in (b).
JP 2000-41415 A

  By the way, if the rotary tiller 504 is moved up to reduce the tilling depth rd, the support shaft 508 connecting the tilling cover 506 and the rear cover 507 moves to a higher position away from the ground G (FIG. 17A). reference). If the rotary cultivator 504 is moved downward to increase the tilling depth rd, the position of the support shaft 508 moves to a lower position near the ground G (see FIG. 17B).

Thus, when the rotation center position of the rear cover body 507 with respect to the rotary tiller 504 (the position of the support shaft 508) is displaced in the vertical direction, the tilling depth of the rotary tiller 504 is interlocked with the displacement of the rotation center position. The amount of change in the vertical rotation angle γ of the rear cover body 507 with respect to the amount of change in the length rd also changes.

  For example, the higher the support shaft 508 is at a higher position away from the ground G, the closer the rear cover body 507 is to a vertical posture with respect to the ground G, and the state is suspended from the rear end of the tilling cover body 506. The amount of change in the vertical rotation angle γ in the rear cover body 507 increases with respect to a small change in the tilling depth rd in the rotary tiller 504. Therefore, the detection sensitivity of the rear cover sensor 509 becomes sensitive to the unevenness of the ground G.

  On the contrary, as the support shaft 508 comes to a lower position near the ground G, the rear cover body 507 approaches a horizontal posture with respect to the ground G and is in a state of pressing the ground G from above by its own weight, etc. With respect to a large change in the tilling depth rd in the rotary tiller 504, the amount of change in the vertical rotation angle γ in the rear cover body 507 becomes small. Accordingly, the detection sensitivity of the rear cover sensor 509 is insensitive to the unevenness of the ground G.

  However, in the agricultural machine of Patent Document 1, the control gain when calculating the tilling depth rd of the rotary tiller 504 is always constant regardless of the depth of the tilling depth rd. If it is suitable for a shallow tillage depth rd, when the rotary tiller 504 is moved downward to increase the tillage depth rd, the detection sensitivity of the rear cover sensor 509 is too insensitive, and the tilling depth is automatic. There was a problem that the accuracy of control was lowered.

  Further, if the constant control gain is suitable when the tillage depth rd is deep, the detection sensitivity of the rear cover sensor 509 is too sensitive when the rotary tiller 504 is moved downward to reduce the tillage depth rd. Therefore, the rotary cultivator 504 moves up and down unnecessarily due to the effects of weeds and unevenness on the ground G (the lifting control hydraulic cylinder repeats expansion and contraction in small increments), so-called hunting phenomenon frequently occurs, and the accuracy of automatic tilling depth control There was a problem that decreased.

  In short, when the control gain when calculating the tilling depth rd of the rotary tiller 504 is always constant, the automatic control of the tilling depth is performed by the change in the detection sensitivity of the rear cover sensor 509 as the rotary tiller 504 moves up and down. A decrease in accuracy was inevitable.

  Therefore, the present invention performs highly accurate automatic tiller depth control without being influenced by the change in detection sensitivity of the tiller detecting means accompanying the up and down movement of the rotary tiller, and hence the depth of tillage of the rotary tiller. It is a technical problem to provide a farm machine that can be used.

  In order to achieve this technical object, the invention of claim 1 is a rotary cultivator mounted on the rear part of a traveling machine body having front wheels and rear wheels and mounted with an engine so as to be adjustable up and down via a link mechanism. And a control means for performing automatic tilling depth control by controlling the drive of a lifting control actuator that moves the rotary tiller up and down. A rear cover body that can be grounded is provided so as to be rotatable up and down, and is provided with a tilling depth detecting means that detects an up and down rotation angle of the rear cover body, and the traveling machine body includes a target tillage depth of the rotary tiller. A tilling depth setting device for presetting the depth is provided, the control means is provided with storage means for storing a control gain in advance, and the control means is set by the tilling depth setting device. The control gain is changed according to the control information corresponding to the target tillage depth, so that the tillage depth of the rotary tiller obtained from the detection information of the tillage depth detecting means becomes the target tillage depth. The drive of the lift control actuator is controlled by the changed control gain.

The invention of claim 2 is a rotary cultivator mounted on the rear part of a traveling machine body having a front wheel and a rear wheel and mounted with an engine so as to be adjustable up and down via a link mechanism, and moving up and down the rotary cultivator. And a control means for performing automatic tilling depth control by controlling the drive of the lifting control actuator, wherein the rotary tiller has a rear cover body that can be grounded on the ground. And a plowing depth detecting means for detecting a vertical rotation angle of the rear cover body, the plowing depth for presetting a target plowing depth of the rotary cultivator in the traveling machine body. A setting device is provided, and the control means is provided with storage means for storing a dead zone for the tilling depth automatic control in advance, and the control means is set by the tilling depth setting device. The dead zone is changed according to the control information corresponding to the target tillage depth, and when the detection information of the tillage depth detecting means is within the changed dead zone, drive control of the lifting control actuator is not executed. That's it.

  According to a third aspect of the present invention, there is provided a rotary cultivator mounted on the rear part of a traveling machine body having a front wheel and a rear wheel and mounted with an engine so as to be adjustable up and down via a link mechanism, and moving up and down the rotary cultivator. And a control means for performing automatic tilling depth control by controlling the drive of the lifting control actuator, wherein the rotary tiller has a rear cover body that can be grounded on the ground. And a plowing depth detecting means for detecting a vertical rotation angle of the rear cover body, the plowing depth for presetting a target plowing depth of the rotary cultivator in the traveling machine body. A setter is provided, and the control means is connected to the plowing depth detection means via a filter unit, and the control means is responsive to the target tillage depth set by the plowing depth setter. The cut-off frequency or the center frequency of the filter unit is changed, and the raising / lowering is performed so that the tilling depth of the rotary tiller becomes the target tilling depth based on output information from the tilling depth detecting means via the filter unit. It controls the drive of the control actuator.

  According to the first aspect of the present invention, the control means for controlling the drive of the lifting control actuator changes the control gain according to the control information corresponding to the target tilling depth set by the tilling depth setting device. The control gain when the tilling depth is set to be small (shallow) is a small value that reduces the influence of the sensitive detection sensitivity of the tilling depth detecting means when calculating the tilling depth.

  Then, the control unit controls the drive of the lifting control actuator with the small control gain so that the tilling depth obtained from the detection information of the tilling depth detecting unit becomes the target tilling depth. That is, the control means calculates the tillage depth based on the control gain of the small value and the detection information of the tillage depth detection means, and the elevation control is performed so that the calculated tillage depth becomes the target tillage depth. Controls actuator drive. As a result, the hunting phenomenon of the rotary tiller due to the effects of weeds and unevenness on the ground is eliminated or significantly suppressed.

  The control gain when the target tillage depth is set large (deep) is a large value that increases the influence of the detection sensitivity of the tillage depth detecting means when calculating the tillage depth of the rotary tiller. Become.

  Then, the control means controls the drive of the lifting control actuator with the large control gain so that the tilling depth obtained from the detection information of the tilling depth detecting means becomes the target tilling depth. That is, the control means calculates the tilling depth based on the control gain of the large value and the detection information of the tilling depth detecting means, and the raising / lowering control is performed so that the calculated tilling depth becomes the target tilling depth. Controls actuator drive. As a result, the same action as that obtained by improving the detection sensitivity of the tilling depth detecting means can be obtained.

  In summary, according to the first aspect, the rotary tiller is moved up and down by changing the control gain according to the control information corresponding to the target tilling depth set by the tilling depth setting device. It is possible to compensate for the adverse effect caused by the change in detection sensitivity of the plowing depth detection means due to the control gain corresponding to the target plowing depth at this time, so that it depends on the depth of the plowing depth in the rotary tiller. In addition, there is an effect that it is possible to execute automatic plowing depth automatic control with high accuracy.

  According to invention of Claim 2, a control means changes the dead zone for tilling depth automatic control according to the control information corresponding to the target tilling depth set by the tilling depth setting device, and the tilling depth When the detection information of the detection means is within the changed dead zone, the lift control actuator is not driven. For example, when the target tillage depth is set small (shallow), this shallow target tillage depth can be handled. Within the dead zone range, even if the control gain when calculating the tillage depth is constant, the change in the detection information of the tillage depth detecting means due to the effects of weeds and unevenness on the ground is ignored. Thus, the hunting phenomenon of the rotary tiller can be eliminated or significantly suppressed.

  That is, even if the control gain when calculating the tillage depth is constant, the adverse effect due to the change in the detection sensitivity of the tillage detecting means accompanying the up and down movement of the rotary tiller is affected by the target tillage depth at this time. In this case, as in the first aspect of the invention, high-precision automatic control of tilling depth can be performed without being affected by the depth of tilling in the rotary tiller. There is an effect that it can be executed.

  According to invention of Claim 3, a control means changes the interruption | blocking of a filter part or a center frequency according to the control information corresponding to the target tilling depth set with the tilling depth setting device, and from a tilling depth detection means Based on the output information via the filter unit, the drive of the lifting control actuator is controlled so that the tilling depth of the rotary tiller becomes the target tilling depth. For example, the target tilling depth is set small (shallow). Sometimes, a filter unit having a cutoff frequency or center frequency corresponding to this shallow target tillage depth attenuates unnecessary frequency components due to the effects of weeds and unevenness from the detection information of the tillage depth detecting means (passing through). As a result, even if the control gain when calculating the tillage depth is constant, the hunting phenomenon of the rotary tiller can be eliminated or significantly suppressed. That.

  That is, even if the control gain when calculating the tillage depth is constant, the adverse effect due to the change in the detection sensitivity of the tillage detecting means accompanying the up and down movement of the rotary tiller is affected by the target tillage depth at this time. Since compensation can be made at a suitable cut-off frequency or center frequency, in this case as well, as in the inventions of claims 1 and 2, high accuracy can be achieved without being influenced by the depth of tillage in the rotary tiller. The effect is that automatic tilling depth control can be executed.

  DESCRIPTION OF EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings (FIGS. 1 to 15).

  1 to 10 show a first embodiment in which the present invention is applied to a tractor. 1 is a side view of the tractor, FIG. 2 is a plan view of the tractor, FIG. 3 is a schematic side view of the lifting mechanism for the work implement, FIG. 4 is a schematic plan view of the lifting mechanism for the work implement, and FIG. FIG. 6 is a schematic rear view of the rotary tiller, FIG. 7 is a hydraulic circuit diagram of the tractor, FIG. 8 is a functional block diagram of the control means, FIG. 9 is a flowchart of automatic tilling depth control, and FIG. It is a figure of the control map which shows the relationship between a control gain and the setting value of a tilling depth setting device.

As shown in FIGS. 1 to 4, the traveling machine body 2 of the tractor 1 in the first embodiment is supported by a pair of left and right rear wheels 4 as well as a pair of left and right front wheels 3. The tractor 1 is configured to travel forward and backward by driving the rear wheels 4 and the front wheels 3 with an engine 5 mounted on the front portion of the traveling machine body 2. The engine 5 is covered with a bonnet 6. Further, a cabin 7 is installed on the upper surface of the traveling machine body 2, and inside the cabin 7, a steering seat 8 is steered to move the steering direction of the front wheels 3 to the left and right. (Round handle) 9 is installed. A step 10 on which the operator gets on and off the cabin 7 is provided, and a fuel tank 11 for supplying fuel to the engine 5 is provided on the inner side of the cabin 10 and below the bottom of the cabin 7. .

  As shown in FIGS. 1 to 4, the traveling vehicle body 2 includes an engine frame 14 having a front bumper 12 and a front axle case 13, and left and right aircraft bodies that are detachably fixed to the rear portion of the engine frame 14 with bolts. Frame 16. A mission case 17 is connected to the rear portion of the body frame 16 for transmitting the rotation of the engine 5 to the rear wheels 4 and the front wheels 3 with appropriate speed change. The rear wheel 4 is attached via a rear axle case 18 mounted so as to protrude outward from the outer surface of the mission case 17.

  As shown in FIGS. 3 and 4, a hydraulic working machine lifting mechanism 20 for lifting and lowering a rotary tiller 24 as a working machine is detachably attached to the rear upper surface of the transmission case 17. Yes. The rotary cultivator 24 is connected to the rear portion of the mission case 17 via a three-point link mechanism including a pair of left and right lower links 21 and a top link 22. The front end sides of the left and right lower links 21 are rotatably connected to the left and right side surfaces of the rear portion of the mission case 17 via lower link pins 25. The front end side of the top link 22 is connected to a top link hitch 26 at the rear part of the working machine lifting mechanism 20 via a top link pin 27. Further, a PTO shaft 23 for transmitting a PTO driving force to the rotary tiller 24 is provided on the rear side surface of the mission case 17 so as to protrude rearward.

  As shown in FIGS. 3, 4, and 7, the hydraulic working machine lifting mechanism 20 has a pair of left and right lift arms 29 that are rotated by a single-acting lifting control hydraulic cylinder 28 described later. is set up. The lower link 21 and the lift arm 29 on the left side in the traveling direction are connected via a left lift rod 30. The lower link 21 and the lift arm 29 on the right side in the traveling direction include a right lift rod 31, a double-acting tilt control hydraulic cylinder 32 that forms a part of the rod 31, and a piston rod 33 of the cylinder 32. And are connected through.

  As shown in FIG. 1, the front end of the lower link frame 34 and the pair of left and right lower links 21 in the rotary cultivator 24 are connected via a lower hitch pin 35a. Each rear end side of the top link 22 and the front end side of the upper link frame 34 are connected via an upper hitch pin 34a.

  As shown in FIGS. 1, 2, 5, and 6, the rotary tiller 24 includes a horizontally long main beam 36, a chain case 37 having upper ends connected to left and right ends of the main beam 36, and A bearing plate 38, a tilling claw shaft 39 whose left and right ends are rotatably supported on the lower end sides of the chain case 37 and the bearing plate 38, and a plurality of tillers radially attached to the tilling claw shaft 39 so as to be detachable. Claw 40, cultivation upper surface cover 41 arranged so as to cover the rotation trajectory of cultivation claw 40, left and right cultivation side cover 42 arranged so as to cover the left and right sides of the rotation trajectory of cultivation claw 40, and cultivation A tilling rear cover 43 arranged so as to cover the rear of the rotation trajectory of the claw 40, a tilling depth adjusting frame 44 attached to the main beam 36 and extending long rearward, and a rear end side of the upper link frame 34 And a stretchable adjustable tilling depth adjustment shaft 45 or the like connecting the longitudinal direction of the intermediate portion of the depth adjusting frame 44. The tillable rear cover 43 corresponds to the rear cover body described in the claims.

  The lower link frame 35 is integrally connected to the main beam 36 (see FIGS. 2 and 6). The top link 22 is configured to be expanded and contracted by rotation of the turnbuckle 22a so that the length of the top link 22 can be changed and adjusted (see FIGS. 3 and 4). An intermediate portion in the front-rear direction of the upper link frame 34 is rotatably connected to the main beam 36 via a tilling depth adjustment fulcrum shaft 34b (see FIG. 1). The front end side of the tilling depth adjusting frame 44 is integrally connected to the main beam 36. When the tilling depth adjusting shaft 45 is expanded and contracted by rotating the tilling depth adjusting handle 45a (see FIG. 1), the rotary tiller 24 supported by the pair of left and right lower links 21 and the top link 22 is tilted forward or rearward. It changes to an inclination posture and the tilling depth RD by the tilling nail 40 is configured to be changeable.

  As shown in FIGS. 1, 5, and 6, a gear case 46 for inputting a driving force from the PTO shaft 23 is disposed at the left and right central portion of the main beam 36. The PTO shaft 23 and the PTO input shaft 46a on the front side of the gear case 46 are connected to each other via a telescopic transmission shaft 46b having universal joints at both ends. The power from the PTO shaft 23 includes a bevel gear (not shown) built in the gear case 46, a rotating shaft (not shown) built in the main beam 36, a sprocket and a chain (not shown) built in the chain case 37. ) And the like, and is transmitted to the tilling claw shaft 39 to rotate the tilling claw 40 counterclockwise in FIGS.

  As shown in FIG. 5 and FIG. 6, the front end side of the tilling rear cover 43 is connected to the rear end portion of the tilling upper surface cover 41 that is long in the left-right width direction of the traveling machine body 2 via a pivot shaft 47. A pair of left and right hanger frames 48 in a rearward inclined posture are erected on the rear upper surface of the tilling upper surface cover 41. The rear end side of the upper surface of the tilling rear cover 43 and the left and right hanger frames 48 are coupled to each other via a pair of left and right hanger mechanisms 49 so as to be movable up and down. A pressure receiving shaft 48a is disposed at the upper end of each hanger frame 48 so as to be rotatable about a horizontal axis (center line).

  The elongated rod-shaped hanger rod 50 in each hanger mechanism 49 penetrates the pressure receiving shaft body 48a so as to be slidable in a direction perpendicular to the horizontal axis (center line). The lower end portion of the hanger rod 50 is rotatably connected to a bracket 54 provided on the rear upper surface of the tilling rear cover 43 via a support shaft 53 (see FIG. 5). A lowering restriction pin 51 is provided on the upper end side of the hanger rod 50. On the hanger rod 50 between the pressure receiving shaft body 48 a and the lowering restriction pin 51, a donut-shaped lowering restriction plate 52 is fitted so as to be slidable in the axial direction of the hanger rod 50. In addition, on the lower side of the hanger rod 50 (above the support shaft 53), an ascending restriction pin 55 is disposed. The hanger rod 50 between the pressure receiving shaft body 48a and the rise restricting pin 55 is covered with a pressure reducing compression spring 58 for applying pressure to the tilling rear cover 43 via donut-shaped upper and lower seat plates 56, 57. It is fitted.

  When the rotary tiller 24 is lifted to a height away from the ground G, the rear end side of the tilling rear cover 43 rotates downward about the pivot shaft 47. Then, the lowering restriction pin 51 comes into contact with the lowering restriction plate 52, and the lowering restriction plate 52 comes into contact with the pressure receiving shaft body 48a. As a result, the tilling rear cover 43 is maintained in a posture in which the rear end side is lowered to the lowest.

  On the other hand, when the rotary tiller 24 is lowered to the ground G and the tilling pawl 40 is landed or during the tilling work, the rear end side of the tilling rear cover 43 is rotated around the pivot shaft 47 by the contact pressure with the tilled tillage. Will rotate upward. Further, when the rear end side of the tilling rear cover 43 is pivoted upward about the pivot shaft 47, the pressure reducing compression spring 58 is compressed via the rise restricting pin 55 and the lower seat plate 57, and the rear end of the tilling rear cover 43. The upward rotation on the side is restricted by the biasing force of the compression spring 58 for pressure suppression. As a result, the amount of cultivated soil discharged from the cultivating claw 40 to the rear of the cultivating rear cover 43 is limited, or the ground is leveled by the movement of the cultivating rear cover 43.

  FIG. 7 shows the hydraulic circuit 100 of the tractor 1. The hydraulic circuit 100 includes a working machine hydraulic pump 101 that is operated by the rotational force of the engine 5. The work machine hydraulic pump 101 includes a lift control solenoid valve 102 and a drop control solenoid valve 103 for supplying and controlling hydraulic oil to the lift control hydraulic cylinder 28 in the work machine lifting mechanism 20, and a tilt control hydraulic cylinder 32. Is connected to an inclination control electromagnetic valve 104 for controlling the supply of the air through a flow dividing valve 105. The hydraulic circuit 100 also includes a relief valve, a flow rate adjustment valve, a check valve, an oil cooler, an oil filter, and the like (see FIG. 7).

  Next, the structure of the various operation means arrange | positioned in the cabin 7 is demonstrated. As shown in FIGS. 1 and 2, the round handle type steering handle 9 in the cabin 7 is provided on a steering column 60 positioned in front of the steering seat 8. A throttle lever 117 for adjusting the rotational speed (output) of the engine 5 and a left and right brake pedal 61 for braking the traveling machine body 2 are provided on the right side of the steering column 60. A clutch pedal 62 is disposed on the left side of the steering column 60.

  On the right column of the control seat 8, the working target lift lever 63 for manually changing and adjusting the height position of the rotary tiller 24, the PTO shift lever 64, and the relative target of the rotary tiller 24 with respect to the traveling machine body 2. An inclination setting unit 123 including a variable resistor for setting a right and left inclination angle in advance, and a tilling depth setting unit 126 including a variable resistor for setting a target tilling depth RD0 of the rotary tiller 24 in advance Has been placed. The inclination setting device 123 and the tilling depth setting device 126 are configured so that the position of the knob (pointer) can be changed continuously (analog) or stepwise (digital). A travel speed change lever 65 is arranged on the left column of the control seat 8. A differential lock pedal 66 is disposed in front of the left column of the control seat 8.

  Next, a configuration for tilling control (automatic tilling depth control and rolling automatic control) of the rotary tiller 24 will be described with reference to FIG.

  A tillage control controller 110 as a control means including a ROM 110a storing a control program and the like and a RAM 110b capable of storing various data is connected to a battery 112 via a key switch 111 for applying power. The key switch 111 is configured to be connectable to a starter 113 for starting the engine 5.

  In the ROM 110a of the tillage control controller 110, a relational expression showing the relationship between the control gain Ga used when calculating the tilling depth RD of the rotary tiller 24 and the set value (target tilling depth RD0) of the tilling depth setting device 126. Alternatively, a control map is stored in advance. The ROM 110a of the first embodiment corresponds to the storage means in claim 1.

  In this case, Ga = A × RD0 + B is given as a relational expression. Here, A is a proportionality constant, and B is a constant. Such a relational expression is obtained by experiments or the like. FIG. 10 shows a case where this relational expression is used as a control map. In FIG. 10, the setting value (target tilling depth RD0) of the tilling depth setter is taken on the horizontal axis, and the control gain Ga is taken on the vertical axis.

  In addition, you may make it memorize | store the data of a pair of the setting value (target tilling depth RD0) of the tilling depth setting device 126 and the control gain Ga corresponding to this in the ROM 110a of the tilling control controller 110 as a table map.

An electronic governor controller 114 that controls the rotation of the engine 5 is connected to the tillage control controller 110. The electronic governor controller 114 is connected to a governor 115 that adjusts the fuel of the engine 5 and an engine rotation sensor 116 that detects the rotational speed of the engine 5.

  When the operator manually operates the throttle lever 117, the electronic governor controller 114 determines the set rotational speed of the throttle lever 117 and the rotational speed of the engine 5 based on the detection information of the throttle potentiometer 118 that detects the rotational position of the throttle lever 117. Are controlled so as to automatically adjust the position of the fuel adjustment rack by the throttle solenoid 119. As a result, the rotational speed of the engine 5 is maintained at a predetermined rotational speed corresponding to the position of the throttle lever 117, regardless of load fluctuations.

  Further, the tillage control controller 110 includes various switches and sensors of the input system, for example, the tilt setting device 123 and the tilling depth setting device 126 described above, and a pendulum type body for detecting the right and left tilt angle of the traveling machine body 2. In order to detect the rotational speed (traveling speed) of the rolling sensor 120, the potentiometer type work machine position sensor 122 for detecting the relative right and left inclination angle of the rotary tiller 24 with respect to the traveling machine body 2, and the front and rear four wheels 3 and 4. A vehicle speed sensor 127, a potentiometer type lift angle sensor 129 for detecting the rotation angle of the lift arm 29, a potentiometer type rear cover sensor 124 for detecting the vertical rotation angle of the tilling rear cover 43, and the like are connected. The rear cover sensor 124 corresponds to the tilling depth detecting means described in the claims.

  The airframe rolling sensor 120 is disposed on the upper surface of the working machine lifting mechanism 20 and at a position behind the control seat 8 (see FIGS. 1 to 4). Although not shown in detail, the work implement position sensor 122 is disposed at the left and right center of the main beam 36 located above the tilling upper surface cover 41. The lift angle sensor 129 is disposed at a connection point between the work machine lifting mechanism 20 and the left lift arm 29 (see FIGS. 3 and 4).

  The rear cover sensor 124 as the tilling depth detecting means is disposed on the rear upper surface of the tilling upper surface cover 41 (see FIGS. 2, 5, and 6). The rear cover sensor 124 and the tilling rear cover 43 are connected via a sensor arm 67, a sensor link 68, and the like. The rear cover sensor 124 is connected to the tillage control controller 110 via a filter unit 125 including, for example, a low-pass filter (low-pass filter).

  Further, the output control various solenoid valves, that is, the lift control solenoid valve 102, the drop control solenoid valve 103, and the tilt control solenoid valve 104 are connected to the tillage control controller 110.

  The tillage control controller 110 changes the control gain Ga according to the control information (signal) corresponding to the target tilling depth RD0 set by the tilling depth setting device 126, and the changed control gain Ga and the rear cover sensor 124 are changed. On the basis of the detected value θ, the raising control solenoid valve 102 or the lowering control solenoid valve 103 is switched and the raising / lowering control hydraulic cylinder 28 is driven to extend and contract, whereby the tilling depth RD of the rotary tiller 24 becomes the target tilling depth RD0. Thus, the tilling depth automatic control of the rotary tiller 24 is executed (detailed mode will be described later).

  Further, the tillage control controller 110 switches the tilt control solenoid valve 104 and drives the tilt control hydraulic cylinder 32 to expand and contract based on the detection information of the machine body rolling sensor 120 and the work machine position sensor 122, so that the rotary tiller 24 Rolling automatic control of the rotary tiller 24 is executed so that the left / right inclination angle becomes the target left / right inclination angle set by the inclination setting device 123.

  Next, an example of automatic tilling depth control of the rotary tiller 24 in the first embodiment will be described with reference to the flowchart shown in FIG.

  First, the rotary tiller 24 is connected to the rear side of the tractor 1 via the lower link 21 and the top link 22 so as to be adjustable up and down, and then the engine 5 of the tractor 1 is started and an automatic control switch (not shown). The tilling depth automatic control is executed by the ON operation of (Start).

  Following the start, the operator operates the tilling depth setting device 126 to set the target tilling depth RD0 of the rotary tiller 24, and stores the target tilling depth RD0 in the RAM 110b of the tilling control controller 110 (step S1). .

  Next, the set value of the tilling depth setting device 126 (target tilling depth RD0), the detected value of the lift angle sensor 129, and the detected value θ of the rear cover sensor 124 are read (step S2). The detection value of the lift angle sensor 129 is used to determine the height of the rotary tiller 24 relative to the body (the relative height of the rotary tiller 24 with respect to the traveling body 2).

  Next, from the setting value (target tilling depth RD0) of the tilling depth setting device 126 read in step S2 and the relational expression or control map stored in advance in the ROM 110a of the tilling control controller 110, the tilling of the rotary tiller 24 is performed. A control gain Ga used when calculating the depth RD is obtained (step S3). In this case, the control gain Ga increases as the set value (target tilling depth RD0) of the tilling depth setting device 126 decreases from small to large (shallow to deep) (see FIG. 10).

  After calculating the control gain Ga in step S3, the current tilling depth RD (see FIG. 1) in the rotary tiller 24 is calculated from the calculated control gain Ga and the detected value θ of the rear cover sensor 124 (see FIG. 1) (see FIG. 1). Step S4).

  Next, it is determined whether or not the current tillage depth RD in the rotary tiller 24 matches the target tillage depth RD0 that is the set value of the tillage depth setting device 126 (step S5). When it is determined that the current tillage depth RD does not coincide with the target tillage depth RD0 (S5: NO), the lift control solenoid valve 102 or the descend control solenoid valve 103 is driven up and down. By extending and retracting the control hydraulic cylinder 28, the current tillage depth RD in the rotary tiller 24 is adjusted and corrected so as to coincide with the target tillage depth RD0 (step S6). Thereafter, one cycle of automatic tilling depth control is completed and the process returns.

  Returning to step S5, when it is determined that the current tillage depth RD matches the target tillage depth RD0 (S5: YES), the ascent control solenoid valve 102 and the descending control solenoid valve 103 are returned to the neutral position. Maintain and stop the lifting control hydraulic cylinder 28 (step S7). After that, one cycle of tilling depth automatic control is completed and the process returns.

  According to the above control, for example, when the target tilling depth RD0 is set to be small (shallow) by the tilling depth setting device 126, the tilling rear cover 43 approaches a vertical posture with respect to the ground G, and the rear cover sensor 124 detects it. Sensitivity becomes sensitive to unevenness of the ground G. On the other hand, the control gain Ga at this time is a small value corresponding to the control information of the target tillage depth RD0. In other words, the control gain Ga is a small value that reduces the influence of the sensitive detection sensitivity of the rear cover sensor 124 when calculating the tilling depth RD of the rotary tiller 24.

  Then, the tillage control controller 110 calculates the tilling depth RD of the rotary tiller 24 from the small control gain Ga and the detected value θ of the rear cover sensor 124, and the calculated tilling depth RD is the target tilling depth. Since the lift control hydraulic cylinder 28 is extended and retracted so as to be RD0, the so-called hunting phenomenon in which the rotary tiller 24 moves up and down unnecessarily due to the effects of weeds and unevenness on the ground G is eliminated or significantly reduced. It is suppressed. Therefore, the automatic tilling depth control when the target tilling depth RD0 is shallow can be appropriately executed.

  On the other hand, when the target tilling depth RD0 is set large (deep) by the tilling depth setting device 126, the tilling rear cover 43 comes close to a horizontal posture with respect to the ground G, and the detection sensitivity of the rear cover sensor 124 becomes the ground sensitivity. Insensitive to unevenness changes. On the other hand, the control gain Ga at this time is a large value corresponding to the control information of the target tillage depth RD0. That is, the control gain Ga increases the influence of the detection sensitivity of the rear cover sensor 124 when calculating the tilling depth RD of the rotary tiller 24 (as if the detection sensitivity of the rear cover sensor 124 has improved). Large value.

  Then, the tillage control controller 110 calculates the tilling depth RD of the rotary tiller 24 from the large control gain Ga and the detection value θ of the rear cover sensor 124, and the calculated tilling depth RD is the target tilling depth. Since the elevation control hydraulic cylinder 28 is driven to extend and stop so as to be RD0, the same effect as that obtained by improving the detection sensitivity of the rear cover sensor 124 can be obtained. Therefore, automatic tilling depth automatic control when the target tilling depth RD0 is deep can be appropriately executed.

  In short, the detection sensitivity of the rear cover sensor 124 accompanying the up and down movement of the rotary tiller 24 is changed by changing the control gain Ga according to the control information corresponding to the target tilling depth RD0 set by the tilling depth setting device 126. Since the adverse effect due to the change is compensated by the control gain Ga commensurate with the target tillage depth RD0 at this time, the highly accurate tillage depth automatic control is not affected by the depth of the tillage depth RD in the rotary tiller 24. Can be executed.

  Next, a second embodiment in which a dead zone is employed in order to suppress the influence of a change in detection sensitivity of the rear cover sensor will be described with reference mainly to FIGS. 11 and 12. FIG. 11 is a flowchart of tilling depth automatic control in the second embodiment, and FIG. 12 is an explanatory diagram of dead zone changing control in tilling depth automatic control. Here, in the second and subsequent embodiments, the same configuration and operation as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted.

  In the second embodiment, the control gain when calculating the tilling depth RD of the rotary tiller 24 is constant, and the ROM 110a of the tillage controller 110 includes, for example, a standard width dead band δF1, a narrow width dead band. This is different from the first embodiment in that data relating to three types of dead zones δF, δF2 and wide dead zone δF3, are stored in advance. Here, the dead zone δF means that if the tilling depth RD of the rotary tiller 24 is within a predetermined vertical width range centered on the target tilling depth RD0, the lifting control hydraulic cylinder 28 is not driven, and the tilling depth If RD is out of the vertical width range, it means an operation gap in which the lifting control hydraulic cylinder 28 is moved up and down to bring the tilling depth RD closer to the target tilling depth RD0.

  The dead zone δF1 of the standard width corresponds to the medium target cultivation depth RD0b. The narrow dead zone δF2 corresponds to a large target tillage depth RD0c. The wide dead zone δF3 corresponds to the target tilling depth RD0a having a small value.

  The ROM 110a of the second embodiment corresponds to the storage means in claim 2. It should be noted that a relational expression or a control map indicating the relationship between the dead zone δF and the setting value (target tilling depth RD0) of the tilling depth setting device 126 may be stored in the ROM 110a. There is no need for the narrow dead zone δF2 corresponding to the target tilling depth RD0c having a large value.

  In the above configuration, the tilling depth automatic control of the rotary tiller 24 in the second embodiment is executed as follows, for example (see FIG. 11).

  First, the rotary tiller 24 is connected to the rear side of the tractor 1 via the lower link 21 and the top link 22 so as to be adjustable up and down, and then the engine 5 of the tractor 1 is started and an automatic control switch (not shown). The tilling depth automatic control is executed by the ON operation of (Start).

  Following the start, the operator operates the tilling depth setting device 126 to set the target tilling depth RD0 of the rotary tiller 24, and stores the target tilling depth RD0 in the RAM 110b of the tilling control controller 110 (step T1). .

  Next, the set value of the tilling depth setting device 126 (target tilling depth RD0), the detected value of the lift angle sensor 129, and the detected value θ of the rear cover sensor 124 are read into the tilling control controller 110 (step T2).

  Next, the dead zone δF corresponding to the target tillage depth RD0 read in step S2 is selected from the data of the ROM 110a in the tillage controller 110 (step T3). At this time, if the target tillage depth RD0a is small (shallow), a wide dead zone δF3 is selected. If the target tillage depth RD0b is medium, a standard width dead zone δF1 is selected. If the target tillage depth RD0c is large (deep), a narrow dead zone δF2 is selected (see FIG. 12).

  After selecting the optimum dead zone δF in step T3, the current tillage depth RD (see FIG. 1) in the rotary tiller 24 is calculated from the detected value θ of the rear cover sensor 124 (step T4).

  Next, it is determined whether or not the current tillage depth RD in the rotary tiller 24 is within a dead zone ± δF centered on the target tillage depth RD0 (RD0−δF ≦ RD ≦ RD0 + δF) (step T5). . When it is determined that the current tillage depth RD is out of the range of the dead zone ± δF centered on the target tillage depth RD0 (T5: NO), either the ascending control solenoid valve 102 or the descending control solenoid valve 103 By either of these drivings, the lifting control hydraulic cylinder 28 is extended and contracted to adjust / correct the current tilling depth RD in the rotary tiller 24 so as to approach the target tilling depth RD0 (step T6). Thereafter, one cycle of automatic tilling depth control is completed and the process returns.

  Returning to step T5, when it is determined that the current tillage depth RD is within the dead zone ± δF centered on the target tillage depth RD0 (T5: YES), the ascending control solenoid valve 102 and the descending control solenoid The valve 103 is returned to and maintained at the neutral position, and the elevation control hydraulic cylinder 28 is stopped (step T7). After that, one cycle of tilling depth automatic control is completed and the process returns.

  According to the above control, for example, when the target tilling depth RD0 is set small (shallow) by the tilling depth setting device 126, the detection sensitivity of the rear cover sensor 124 becomes sensitive to the unevenness of the ground G, but is small. Since the wide dead zone δF3 centered on the target tillage depth RD0a of the value is adopted (see FIG. 12), the weeds on the ground G are within the range of the wide dead zone ± δF3 (RD0a−δF3 ≦ RD ≦ RD0a + δF3). It can be ignored that the detection value θ of the rear cover sensor 124 changes little by little due to the influence of the unevenness.

  Thereby, even if the control gain when calculating the tilling depth RD of the rotary tiller 24 is constant, the hunting phenomenon of the rotary tiller 24 due to the effects of weeds and unevenness on the ground G is eliminated or significantly suppressed. As a result, similarly to the first embodiment, it is possible to appropriately execute the automatic tilling depth control when the target tilling depth RD0a is shallow.

  Further, when the target tillage depth RD0 is set to be large (deep) by the tilling depth setting device 126, the detection sensitivity of the rear cover sensor 124 becomes insensitive to the unevenness of the ground, but a large target tillage depth is set. Since the narrow dead zone δF2 centered on RD0c is employed, the influence of the dead zone δF2 on the detection value θ of the rear cover sensor 124 is minimized. Thereby, the detection accuracy of the rear cover sensor 124 is maintained, and consequently, the accuracy of the automatic tilling depth control when the target tilling depth RD0c is deep is maintained.

  In short, in the second embodiment, the tilling depth RD of the rotary tiller 24 is changed by changing the dead zone δF according to the control information corresponding to the target tilling depth RD0 set by the tilling depth setting device 126. Even if the control gain at the time of calculation is constant, an adverse effect due to a change in detection sensitivity of the rear cover sensor 124 caused by the up and down movement of the rotary tiller 24 is compensated by the dead zone δF corresponding to the target tillage depth RD0 at this time. As in the first embodiment, highly accurate tiller depth automatic control can be executed without being affected by the depth of the tiller depth RD in the rotary tiller 24.

  Next, a third embodiment using a filter unit to suppress the influence of a change in detection sensitivity of the rear cover sensor will be described mainly with reference to FIGS. FIG. 13 is a flowchart of automatic tilling depth control in the third embodiment, FIG. 14 is a control map showing the relationship between the cut-off frequency and the setting value of the tilling depth setting device, and FIG. 15 shows the transmission frequency characteristics of the low-pass filter. FIG.

  As described above, the rear cover sensor 124 is connected to the tillage control controller 110 via the filter unit 125 (see FIG. 8). This filter unit 125 has the property of attenuating unnecessary frequency components from the detection information (signal) of the rear cover sensor 124 and passing only the necessary frequency components.

  As the filter unit 125, a low-pass filter (low-pass filter, LPF), a high-pass filter (high-pass filter, HPF), a band filter (band-pass filter, BPF), or a band elimination filter (band elimination filter, BEF) is adopted. it can. In the third embodiment, a low-pass filter is employed as the filter unit 125. As is well known, the low-pass filter is configured such that a signal in a frequency range higher than the cutoff frequency fc is substantially 0 (zero), and a signal in a frequency range equal to or lower than the cutoff frequency fc is passed as it is. The cut-off frequency fc is a boundary value between the frequency pass band and the attenuation band.

  The cut-off frequency fc employed by the filter unit 125 is variable according to control information corresponding to the setting value (target tilling depth RD0) of the tilling depth setting device 126. That is, the cutoff frequency fc is calculated by the tillage control controller 110 from the control information of the target tillage depth RD0 set by the tilling depth setting device 126, and the control information of the calculation result is transmitted to the film unit 125. Thus, a filter unit 125 (low-pass filter) having a cutoff frequency fc is formed.

  For example, in the case of an LC filter (a filter composed of a coil and a capacitor), this variable configuration can be realized by using a variable capacitor. In the case of an RC filter (a filter composed of a resistor and a capacitor), it can be realized by a combination of a variable resistor and a variable capacitor.

The ROM 110a of the tillage control controller 110 stores in advance a relational expression or a control map indicating the relationship between the cutoff frequency fc and the set value of the tilling depth setting unit 126 (target tilling depth RD0). As a relational expression in this case, fc = C × RD0 + D can be cited. Here, C is a proportionality constant, and D is a constant. Such a relational expression is obtained by experiments or the like. FIG. 14 shows a case where this relational expression is used as a control map. In FIG. 14, the set value (target tilling depth RD0) of the tilling depth setter is taken on the horizontal axis, and the cutoff frequency fc is taken on the vertical axis.

  In addition, you may make it memorize | store the data of a pair of the setting value (target tilling depth RD0) of the tilling depth setting device 126 and the cut-off frequency fc corresponding to this in the ROM 110a of the tilling control controller 110 as a table map. Also in the third embodiment, the control gain when calculating the tilling depth RD of the rotary tiller 24 is constant (constant).

  In the above configuration, the tilling depth automatic control of the rotary tiller 24 in the third embodiment is executed as follows, for example (see FIG. 13).

  First, the rotary tiller 24 is connected to the rear side of the tractor 1 via the lower link 21 and the top link 22 so as to be adjustable up and down, and then the engine 5 of the tractor 1 is started and an automatic control switch (not shown). The tilling depth automatic control is executed by the ON operation of (Start).

  Following the start, the operator operates the tilling depth setting device 126 to set the target tilling depth RD0 of the rotary tiller 24, and stores the target tilling depth RD0 in the RAM 110b of the tilling control controller 110 (step E1). .

  Next, after reading the set value (target tillage depth RD0) of the tillage depth setting device 126 into the tillage control controller 110 (step E2), the set value (target tillage depth RD0) and the ROM 110a of the tillage control controller 110 are stored. The cutoff frequency fc of the filter unit 125 is calculated from the relational expression or the control map stored in advance (step E3). The cut-off frequency fc in this case increases as the target tillage depth RD0 decreases from small to large (shallow to deep) (see FIGS. 14 and 15).

  After calculating the cut-off frequency fc in step E3, the control information of the calculated cut-off frequency fc is transmitted to the filter unit 125, thereby forming the filter unit 125 (low-pass filter) having the cut-off frequency fc ( Step E4).

  Next, after reading the detected value of the lift angle sensor 129 and the output value θf from the rear cover sensor 124 via the filter unit 125 into the tillage control controller 110 (step E5), based on the output value θf via the filter unit 125. The current tillage depth RD (see FIG. 1) in the rotary tiller 24 is calculated (step E6).

  Next, it is determined whether or not the current tillage depth RD in the rotary tiller 24 matches the target tillage depth RD0 that is the set value of the tillage depth setting device 126 (step E7). When it is determined that the current tillage depth RD does not coincide with the target tillage depth RD0 (E7: NO), the lift control solenoid valve 102 or the descend control solenoid valve 103 is driven up and down. By extending and retracting the control hydraulic cylinder 28, the current tillage depth RD in the rotary tiller 24 is adjusted and corrected so as to coincide with the target tillage depth RD0 (step E9). Thereafter, one cycle of automatic tilling depth control is completed and the process returns.

  Returning to step E7, when it is determined that the current tillage depth RD matches the target tillage depth RD0 (E7: YES), the up control solenoid valve 102 and the down control solenoid valve 103 are returned to the neutral position. Maintain and stop the lifting control hydraulic cylinder 28 (step E8). After that, one cycle of tilling depth automatic control is completed and the process returns.

According to the above control, for example, when the target tilling depth RD0 is set small (shallow) by the tilling depth setting device 126, the detection sensitivity of the rear cover sensor 124 becomes sensitive to the unevenness of the ground G, but the filter Since the cut-off frequency fc of the part 125 becomes a small value fc1 corresponding to the target tillage depth RD0, the pass band of the filter part 125 is narrowed, and a frequency component higher than the cut-off frequency fc is cut (FIG. 15). (See the two-dot chain line).

  Then, the tillage control controller 110 calculates the tilling depth RD of the rotary tiller 24 based on the signal (output value θf) in the frequency range below the cutoff frequency fc, and the calculated tilling depth RD is the target tilling depth. The lift control hydraulic cylinder 28 is extended or stopped so as to be RD0, so that it is on the ground G even if the control gain when calculating the tilling depth RD of the rotary tiller 24 is constant. The hunting phenomenon of the rotary tiller 24 due to the effects of weeds and unevenness is eliminated or significantly suppressed. Therefore, similarly to the first and second embodiments, the tilling depth automatic control when the target tilling depth RD0 is shallow can be appropriately executed.

  Further, when the target tilling depth RD0 is set large (deep) by the tilling depth setting device 126, the detection sensitivity of the rear cover sensor 124 becomes insensitive to the unevenness of the ground, but the cutoff frequency fc of the filter unit 125 Becomes a large value fc2 corresponding to the target tillage depth RD0, the pass band of the filter unit 125 is widened, and a relatively high frequency component can be input to the tillage control controller 110 (see the solid line in FIG. 15). ).

  Then, the influence of the filter unit 125 on the detection value θ of the rear cover sensor 124 becomes as small as possible, so that the detection accuracy of the rear cover sensor 124 is maintained. As a result, the accuracy of automatic tilling depth control when the target tilling depth RD0 is deep is achieved. It is maintained.

  In short, in the third embodiment, by changing the cutoff frequency fc of the filter unit 125 according to the control information corresponding to the target tilling depth RD0 set by the tilling depth setting device 126, the rotary tiller 24 Even if the control gain when calculating the tilling depth RD is constant, the adverse effect due to the change in detection sensitivity of the rear cover sensor 124 accompanying the up and down movement of the rotary tiller 24 is blocked in accordance with the target tilling depth RD0 at this time. Since compensation is performed at the frequency fc, it is possible to execute highly accurate tillage depth automatic control without being affected by the depth of the tillage depth RD in the rotary tiller 24 as in the first and second embodiments.

  FIG. 16 shows a modification of the third embodiment. This modification is a case where a band filter is adopted for the filter unit 125.

  As is well known, the bandpass filter is configured to pass the center frequency fc ′ and the signal in the vicinity of the frequency band as it is, and set the signals in the other frequency ranges to almost 0 (zero). The center frequency fc ′ is the center value of the frequency pass band. In the center frequency fc shown in FIG. 16, “1” is added to a small value and “2” is added to a large value.

  Even when such a configuration is adopted, the rotary tiller 24 is changed by changing the cutoff frequency fc ′ of the filter unit 125 according to the control information corresponding to the target tilling depth RD0 set by the tilling depth setting device 126. Even if the control gain when calculating the tilling depth RD of the cultivator is constant, the adverse effect due to the change in detection sensitivity of the rear cover sensor 124 due to the up and down movement of the rotary tiller 24 is commensurate with the target tilling depth RD0 at this time. It can be compensated by the cutoff frequency fc ′.

The present invention is not limited to the above-described embodiment, and can be embodied in various forms. For example, automatic tilling depth control combining the above-described embodiments can be realized. That is, at least two of the three conditions of the control gain Ga, the dead zone δF, and the cutoff (or center) frequency of the filter unit 125 are changed according to the control information corresponding to the target tillage depth RD0. Automatic depth control may be performed. If comprised in this way, it will become possible to further improve the precision of tilling depth automatic control rather than the case of each said embodiment. In addition to the ROM 110a, the storage means according to the present invention includes, for example, an EEPR that can rewrite the stored contents.
A non-volatile memory such as OM may be used.

  In addition, the configuration of each unit is not limited to the illustrated embodiment, and various modifications can be made without departing from the spirit of the present invention.

It is a side view of the tractor in a 1st embodiment. It is a top view of a tractor. It is a schematic side view of the raising / lowering mechanism for working machines. It is a schematic plan view of the raising / lowering mechanism for working machines. FIG. 5 is a side cross-sectional view taken along line VV in FIG. 2. It is a schematic rear view of a rotary tiller. It is a hydraulic circuit diagram of a tractor. It is a functional block diagram of a control means. It is a flowchart of tilling depth automatic control. It is a figure of the control map which shows the relationship between a control gain and the setting value of a tilling depth setting device. It is a flowchart of the cultivation depth automatic control in 2nd Embodiment. It is explanatory drawing of dead zone change control in tilling depth automatic control. It is a flowchart of the cultivation depth automatic control in 3rd Embodiment. It is a figure of the control map which shows the relationship between a cutoff frequency and the setting value of a tilling depth setting device. It is the schematic which shows the transmission frequency characteristic of a low-pass filter. It is the schematic which shows the transmission frequency characteristic of a band filter. It is the schematic of the tilling aspect in the conventional tractor, (a) is a figure when a tilling depth is shallow, (b) is a figure when a tilling depth is deep.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tractor 2 Traveling machine body 3 Front wheel 4 Rear wheel 5 Engine 21 Lower link 22 Top link 24 Rotary tiller 28 Lifting control hydraulic cylinder 43 as a lifting control actuator Tilling rear cover 110 as a rear cover body Tilling control controller 110a as a control means Memory ROM as a means
124 Rear cover sensor 126 as a working depth detection means 126 Working depth setter

Claims (3)

Driven by a rotary tiller mounted on the rear part of a traveling machine body having front wheels and rear wheels and mounted with an engine through a link mechanism so as to be adjustable up and down, and a lift control actuator for moving the rotary tiller up and down A farm work machine provided with a control means for performing automatic tilling depth control by controlling,
The rotary tiller is provided with a rear cover body that can be grounded to the ground so as to be able to rotate up and down, and is provided with a tilling depth detecting means for detecting the vertical rotation angle of the rear cover body,
The traveling machine body is provided with a tilling depth setter for presetting a target tilling depth of the rotary tiller,
The control means includes storage means for storing a control gain in advance.
The control means changes the control gain according to control information corresponding to the target tillage depth set by the tillage depth setting device, and the rotary tiller obtained from the detection information of the tilling depth detection means A farm working machine that controls the drive of the elevating control actuator by the changed control gain so that the plowing depth becomes the target plowing depth. Driven by a rotary tiller mounted on the rear part of a traveling machine body having front wheels and rear wheels and mounted with an engine through a link mechanism so as to be adjustable up and down, and a lift control actuator for moving the rotary tiller up and down A farm work machine provided with a control means for performing automatic tilling depth control by controlling,
The rotary tiller is provided with a rear cover body that can be grounded to the ground so as to be able to rotate up and down, and is provided with a tilling depth detecting means for detecting the vertical rotation angle of the rear cover body,
The traveling machine body is provided with a tilling depth setter for presetting a target tilling depth of the rotary tiller,
The control means includes a storage means for storing a dead zone for the tillage depth automatic control in advance,
The control means changes the dead zone according to control information corresponding to the target tillage depth set by the tillage depth setting device, and the detection information of the tillage depth detecting means is within the changed dead zone range. A farm work machine characterized by not performing drive control of the lift control actuator when it is inside. A rotary cultivator mounted on the rear part of a traveling machine body having front wheels and rear wheels and equipped with an engine so as to be adjustable up and down via a link mechanism, and driving of a lift control actuator for moving the rotary cultivator up and down A farm working machine provided with a control means for performing automatic tilling depth control by controlling,
The rotary cultivator is provided with a rear cover body that can be grounded to the ground so as to be rotatable up and down, and is provided with a tilling depth detecting means for detecting an up and down rotation angle of the rear cover body,
The traveling machine body is provided with a tilling depth setting device for presetting a target tilling depth of the rotary tiller,
The control means is connected to the tilling depth detection means via a filter unit,
The control means changes the cutoff frequency or the center frequency of the filter unit according to control information corresponding to the target tillage depth, and based on output information from the tillage detection means via the filter unit, A farm working machine that controls the drive of the elevating control actuator so that a tilling depth of a rotary tiller becomes the target tilling depth.

Images