JP4728043B2 - Tractor depth control mechanism - Google Patents

Description

  The present invention relates to height control of a work machine mounted on the rear portion of a tractor, and in particular, mounts a rotary tiller device on the tractor, and uses a rear cover provided at the rear portion of the rotary tiller device as a tilling depth sensor to control tilling depth. It is related with the technique of the control means to perform.

Conventionally, a rotary tiller is installed at the rear of the tractor via an elevating mechanism, and the rear cover is pivotally supported at the rear of the tiller cover so that it can be pivoted up and down. The angle of the rear cover is detected by a sensor such as an angle sensor. The plowing depth control of the elevating mechanism that feeds back the output of No. 1 and achieves the set depth set by the plowing depth setting means is well known. Here, while comparing the raising / lowering position of the ground working machine, that is, the plowing depth instructed by the setting unit such as the plowing depth lever of the control unit, with the current working depth of the rotary that is the ground working machine, the setter In the process of automatically following the tilling depth instructed at, when the traveling speed of the tractor increases, the delay in response to the follow command increases, and the sensing unit that senses the tilling depth is slightly on the ground surface. There is a problem that cultivating depth is vibrated and causes hunting due to excessive perception of excessive irregularities. Therefore, in Patent Document 1, with respect to the above-described tilling depth control, a delay in response operation and hunting are improved by providing a dead zone proportional to the height of the vehicle speed.
JP 56-75003 A

  However, if the dead zone is changed simply in proportion to the traveling speed as in the above-mentioned Patent Document 1, when the speed sensor is abnormal, the tilling control does not function and the rotary tiller may move unpredictably. For example, when the value of the speed sensor suddenly becomes a small value due to noise or the like, the dead zone is also reduced, and a sudden elevation may be performed. Also, at the start of work with very low vehicle speed or when slipping occurs, applying the dead zone proportional to the vehicle side to the tilling depth control as it is will reduce the dead zone so that rapid lifting control will be performed instead. Accuracy may deteriorate. Here, the problem to be solved is that in the control means for mounting the rotary tiller at the rear part of the tractor and using the rear cover provided at the rear part of the rotary tiller as the tiller sensor, the vehicle speed sensor Even when an abnormally large value or an abnormally small value is output, at least normal plowing work is possible, and the accuracy of tillage is improved.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  In claim 1, a sensor for detecting a tilling depth, a means for setting a tilling target value, a sensor for detecting a vehicle speed, and a lift arm (14) that is an actuator for raising and lowering a work implement are provided as a controller. In the plowing depth control mechanism of the tractor work machine connected to (32) and controlled to reach the target depth set by the plowing depth setting means, the dead zone for the plowing depth target value is set so that the vehicle speed at the time of work is on the low speed side. If the speed is lower than the speed (A), a predetermined narrow constant width is set. If the speed is higher than the set speed (C) on the high speed side, a predetermined wide constant width is set. If the vehicle speed is less than the set speed (A) on the low speed side and above the set speed (C) on the high speed side, the working machine Actuator to raise and lower An intermediate set speed (B) set between the low speed set speed (A) and the high speed set speed (C) is set to a constant value, which is the speed at which a certain lift arm (14) rotates. If the speed is less than the lower set speed (A), the control gain is increased in proportion to the increase in the vehicle speed, and if the intermediate set speed (B) is less than the higher speed set speed (C), The control gain is decreased in proportion to the increase in the vehicle speed.

In claim 2, a controller for detecting a tilling depth, a means for setting a tilling depth target value, a sensor for detecting a vehicle speed, and a lift arm (14) that is an actuator for raising and lowering a work implement are provided as a controller. In the plowing depth control mechanism of the tractor work machine connected to (32) and controlled to reach the target depth set by the plowing depth setting means, the dead zone for the plowing depth target value is set so that the vehicle speed at the time of work is on the low speed side. If the speed is lower than the speed (A), a predetermined narrow constant width is set. If the speed is higher than the set speed (C) on the high speed side, a predetermined wide constant width is set. If the vehicle speed is less than the set speed (A) on the low speed side and above the set speed (C) on the high speed side, the working machine Actuator to raise and lower Upper limit of the speed is controlled gain to rotate a certain lift arm (14) is a constant value, an intermediate setting speed that is set between the set speed of the low speed side of the set speed (A) and high-speed side (C) If the speed is less than (B) and is equal to or higher than the set speed (A) on the low speed side, the upper limit value of the control gain is increased in proportion to the increase in vehicle speed, and the set speed on the high speed side is increased above the intermediate set speed (B). If it is less than (C), the upper limit value of the control gain is decreased in proportion to the increase in the vehicle speed.

  As effects of the present invention, the following effects can be obtained.

In Claim 1 and Claim 2, the sensor for detecting the working depth, the means for setting the working depth target value, the sensor for detecting the vehicle speed, and the lift arm (14) which is an actuator for raising and lowering the work implement; In the plowing depth control mechanism of the tractor working machine that is connected to the controller (32) and controls to reach the target depth set by the plowing depth setting means, the dead zone for the plowing depth target value is reduced, and the vehicle speed during work is low. If the speed is less than the set speed (A) on the side, a predetermined narrow constant width is set. If the set speed (C) is higher than the high speed side, a predetermined wide constant width is set. When the speed is less than the set speed (C), the speed becomes wider in proportion to the increase in the vehicle speed. Therefore, even when the sensor for detecting the vehicle speed is abnormal in the plowing depth control, the set speed (A) or ( B) In the dead zone Control is possible.
That is, plowing depth control that can be predicted even when the sensor for detecting the vehicle speed is abnormal is possible. Further, when the vehicle speed is very high or conversely very low, the plowing depth control is performed in a certain dead zone, so that the accuracy is improved.

In claim 1, further, when the vehicle speed is less than the set speed (A) on the low speed side and above the set speed (C) on the high speed side, a lift arm (14) that is an actuator for raising and lowering the work implement is provided. The control gain, which is the rotational speed, is set to a constant value, and is less than the intermediate set speed (B) set between the set speed (A) on the low speed side and the set speed (C) on the high speed side. Above the set speed (A), the control gain is increased in proportion to the increase in the vehicle speed, and above the intermediate set speed (B) and below the set speed (C) on the high speed side, in proportion to the increase in the vehicle speed. Since the control gain is reduced, control can be performed with the control gain of the set speed (A) or (B) even when the sensor for detecting the vehicle speed is abnormal.
That is, tilling control that can be predicted even when the sensor for detecting the vehicle speed is abnormal is possible. Further, when the vehicle speed is very high or conversely very low, the plowing depth control is performed with a constant control gain, so that the accuracy is improved.

In claim 2, the upper limit value of the control gain, which is the speed at which the lift arm (14), which is an actuator for raising and lowering the work implement, is set to a constant value, and the set speed (A) on the low speed side and the high speed side are set. Below the intermediate set speed (B) set during the set speed (C) and above the set speed (A) on the low speed side, the upper limit value of the control gain is increased in proportion to the increase in the vehicle speed. Since the upper limit value of the control gain is decreased in proportion to the increase in the vehicle speed at a speed equal to or higher than the speed (B) and lower than the set speed (C) on the high speed side, the optimum control gain obtained experimentally in all speed ranges. When it is not known, by setting only the upper limit value of the control gain, even if the sensor for detecting the vehicle speed is abnormal, control is possible with the upper limit value of the control gain of the set speed (A) or (B) It is.
That is, tilling control that can be predicted even when the sensor for detecting the vehicle speed is abnormal is possible. In addition, when the vehicle speed is very high or conversely very low, the plowing depth control is performed with the upper limit value of each control gain, so that the accuracy is improved.

  Next, embodiments of the invention will be described.

  1 is a side view of a tractor equipped with a rotary tiller according to an embodiment of the present invention, FIG. 2 is a control block diagram of tilling depth control according to an embodiment of the present invention, and FIG. 3 is a control block circuit diagram, FIG. 4 is a diagram showing the relationship between the vehicle speed and the dead zone of the tilling depth control according to the configuration example 1 of the present invention. FIG. 5 is a diagram illustrating the relationship between the vehicle speed and the gain of the tilling depth control according to the first embodiment of the present invention, and FIG. 6 illustrates the relationship between the vehicle speed and the gain upper limit value of the tilling depth control according to the second embodiment of the present invention. FIG.

<Tractor working machine>
Here, a tractor working machine equipped with a rotary tiller as an embodiment of the present invention will be described with reference to FIG.
In FIG. 1, a tractor 1 supports a front wheel 2 at a front portion and a rear wheel 3 at a rear portion, houses an engine 5 in a bonnet 4 on an engine frame, and a steering handle 6 on a dashboard 25 at a rear portion of the bonnet 4. The hydraulic case 8 is placed on the rear transmission case 9 of the steering handle 6, and the seat 7 is arranged above the hydraulic case 8. A main transmission lever 12, a position lever 10, a tilling depth setting dial 31 serving as a tilling depth setting means, and the like are disposed on the side portion of the seat 7.

A rotary tiller 13 is mounted behind the mission case 9 via a work implement mounting device 11. The work implement mounting device 11 includes a top link 15 pivotally connected to a top link bracket attached to the rear surface of the mission case 9, and lower links 16 and 16 pivoted on both sides of the mission case 9 or the rear accelerator housing. Thus, lower ends of lift rods 17 and 17 pivoted to lift arms 14 and 14 projecting rearward from the hydraulic case 8 are pivotally connected to the front and rear middle portions of the lower links 16 and 16, respectively. The rotary tiller 13 is connected to the rear part of the lower links 16, 16, and the rotary tiller 13 can be moved up and down by rotating the lift arm 14.
Note that one of the left and right lift rods 17 is constituted by a hydraulic cylinder, and the inclination of the work implement can be controlled by operating the hydraulic cylinder.

  The rotary tiller 13 transmits power to the gear case of the rotary tiller 13 through a universal joint or the like from the PTO shaft protruding rearward from the rear surface of the transmission case 9, and the transmission shaft in the main beam is transmitted from the gear case. Via the chain transmission mechanism of the chain case 19 arranged on the side, power is transmitted to the tilling claw shaft laid between the lower part of the chain case 19 and the side plate lower part on the opposite side, and fixed to the tilling claw shaft. The tilled claws 20, 20,... Can be rotated. Further, a tillage cover 30 is provided so as to cover the upper and upper rear of the rotation trajectory of the tip of the tilling claws 20, 20,..., And the front end of the rear cover 22 is pivotally supported at the rear end of the tillage cover 30. Yes. Although not shown, the rotation of the rear cover 22 is transmitted via a link mechanism to a rear cover sensor 34 as a tilling depth detecting means including a potentiometer disposed at the rear of the tractor.

<Feedback depth control>
Next, feedback plowing depth control in the case where a tractor equipped with the above-described rotary plowing device performs plowing work will be described with reference to the block diagram of FIG.
In FIG. 2, the signal is transmitted in the direction of the arrow, and the signal represents positive coupling at + and negative coupling at − at the junction indicated by “◯”. Here, from the right side of the figure, the rotation angle of the rear cover 22 that is the current plowing position is detected by the rear cover sensor 34 and fed back to the controller 32 as the rear cover sensor value 36. Further, the control amount (gain) is calculated by the controller 32 from the deviation obtained by comparing and calculating the rear cover sensor value 36 and the tilling depth target value (setting value) 33 set by the tilling depth setting dial 31 on the left side in the figure. Tilling work is performed by moving the lift arm 14 up and down by actuating the electromagnetic with a controlled amount.
Here, a traveling speed value 38 is input to the controller 32 by a traveling speed detection sensor 37 that detects the traveling speed of the tractor. The role of the controller 32 at this time will be described in detail in each configuration example and embodiment. To do.

Next, Configuration Example 1 according to the present invention will be described with reference to FIG. FIG. 3 shows the relationship between the traveling speed of the tractor 1 and the size of the dead zone for the tilling depth control. The dead zone means uncertainty regarding the behavior of the electromagnetic valve 23 that switches the supply of the pressure oil to the hydraulic cylinder that drives the tillage device 13 that actually performs the tillage operation. That is, in this configuration example, it is the detection sensitivity of the rear cover, and is regarded as the fluctuation width of the detection height with respect to the target value (set value). Therefore, if the width of the dead zone is large, it becomes insensitive, and even if the height differs greatly from the target value, the lift arm 14 is not actuated by the hydraulic cylinder. Even if the height deviates, the hydraulic cylinder is driven so as to approach the target value.
A speed setting unit 24 for setting the setting speeds of A, B, and C described later is connected to the controller 32.

Here, the control which changes the dead zone width | variety of the above-mentioned tilling depth control according to the running speed of the tractor 1 shown in FIG. 4 and the following is demonstrated. The controller 32 operates the electromagnetic valve under the following conditions.
(1) If the speed is less than the set speed A, the dead zone width of the tilling depth control is constant at Z1.
(2) When the speed is higher than the set speed A and lower than the set speed B, the dead zone width of the tilling depth control is set to a value proportional to between Z1 and Z2.
(3) When the speed is equal to or higher than the set speed C, the dead zone width of the tilling depth control is constant at Z2.
However, the speed is A <C, the speed A is in the vicinity of the minimum value of the work speed, the speed C is in the vicinity of the maximum value of the work speed, and can be set by the speed setter 24. The dead zone is Z1 <Z2.

  Specifically, the tilling depth control in the configuration example 1 detects the traveling speed by the traveling speed detection sensor 37, and in the low speed range where the detected value is the traveling speed up to A, the size of the dead zone is always as small as Z1. As a result, the electromagnetic valve 23 is actuated when it is slightly separated from the plowing depth target value (set value) 33, and the elevation control is performed so that the target value is reached. Therefore, at the start of work or when the load becomes extremely low due to an increase in load or when the traveling speed is A or more and the traveling speed detection sensor 37 becomes an abnormally small value due to noise or the like. However, the work equipment does not move up and down sensitively, and the finish can be cleaned. When the traveling speed is greater than or equal to A and less than the set speed C, the dead zone increases in proportion to the increase in traveling speed, and normal tilling control is performed. When the traveling speed is equal to or higher than the set speed C, the size of the dead zone is Z2. Therefore, even when the traveling speed detection sensor 37 detects an abnormally fast value due to noise or the like, the dead zone width does not exceed Z2, and the dead zone becomes abnormally large during high-speed work, and there is a portion where the tilling depth control is not performed. Absent. In addition, since the work speed is too high, the dead zone becomes large and control delay does not occur.

  Next, Example 1 according to the present invention will be described with reference to FIG. FIG. 5 shows the relationship between the traveling speed of the tractor 1 and the magnitude of the tilling depth control gain. Here, the gain indicates that the pressure oil is applied to the hydraulic cylinder that is driven to move up and down of the tilling device 13 that actually performs the tilling work. This is a control input value from the controller to the electromagnetic valve 23 that switches oil feeding, and means the speed at which the lift arm 14 is rotated.

Compared with the tilling depth target value (setting value) 33 and the actual rear cover sensor value 36, the gain is increased so that the target value is faster as the difference is larger, and more hydraulic oil is supplied to the hydraulic cylinder. Refueling so that it operates quickly. However, if the lift arm 14 is moved quickly, the inertial force also increases, and the reaction of the tractor 1 that stops when reaching the target value also increases. Here, as shown in FIG. 5 and below, the gain of the above-mentioned tilling depth control according to the traveling speed of the tractor 1 is changed.
(1) If the speed is less than the set speed A, the working depth control gain is constant at G1.
(2) When the speed is greater than or equal to the set speed A and less than the set speed B, the gain of the tilling depth control is set to a value that increases between the gain values G1 and G2 in proportion to the increase in the traveling speed. When the speed is greater than or equal to the set speed B and less than the set speed C, the gain of the tilling depth control is set to a value that decreases between the gain values G2 and G3 in proportion to the increase in traveling speed.
(3) When the speed is higher than the set speed C, the working depth control gain is constant at G3.
However, the speed is A <B <C, and the gain value is G3 <G1 <G2.

  That is, in the first embodiment, the gain is G1, and the hydraulic cylinder is expanded and contracted at a speed corresponding to G1 when the traveling speed is lower than A. At a low working speed that is not less than the set speed A and less than the set speed B, the gain of the tilling depth control is increased in proportion to the increase in the traveling speed, and the hydraulic cylinder moves faster as the speed increases. In a high-speed working area that is greater than or equal to the set speed B and less than the set speed C, the working pressure is gradually decreased by decreasing the working depth control gain in proportion to the increase in traveling speed, Prevents the machine from moving up and down quickly. The gain is decreased at a speed exceeding the set speed C or higher working area so that the hydraulic cylinder is operated slowly. Thus, even if the traveling speed detection sensor 37 detects an abnormally high value or a low value, the gain values G1 and G3 output a low gain to prevent damage due to rapid expansion and contraction of the hydraulic cylinder.

Next, Embodiment 2 according to the present invention will be described with reference to FIG. FIG. 6 shows the relationship between the traveling speed of the tractor 1 and the gain upper limit value of the tilling depth control. Here, as shown in FIG. 6 and below, the above-mentioned tilling depth control gain upper limit value is changed according to the traveling speed of the tractor 1.
(1) If the speed is lower than the set speed A, the gain upper limit value of the tilling depth control is made constant at U1.
(2) When the speed is higher than the set speed A and lower than the set speed B, the gain upper limit value of the tilling control is increased in proportion to the increase in the traveling speed. When the speed is higher than the set speed B and lower than the set speed C, the gain upper limit value of the tilling depth control is decreased in proportion to the increase in the traveling speed.
(3) At the set speed C or higher, the gain upper limit value of the tilling depth control is made constant at U3.
However, the gain upper limit value is U3 <U1 <U2.

  That is, in Example 2, the gain is increased so that the target value becomes faster as the difference between the working depth target value (set value) 33 and the actual rear cover sensor value 36 increases. A large amount of pressure oil is supplied to the cylinder to operate quickly, but the upper limit of the gain is set by the traveling speed. In other words, the upper limit value of the gain is U1 for low-speed traveling where the traveling speed is less than A. At a low work speed that is equal to or higher than the set speed A and lower than the set speed B, the upper limit value of the working depth control gain is increased in proportion to the increase in the traveling speed. In a high-speed working area that is equal to or higher than the set speed B and lower than the set speed C, the upper limit value of the tillage control gain is decreased in proportion to the increase in the traveling speed. The gain upper limit value is set to a small value of U3 at a speed exceeding the set speed C or higher work area. Thus, even if the traveling speed detection sensor 37 detects an abnormally high value or a low value, the gain values G1 and G3 output a low gain to prevent damage due to rapid expansion and contraction of the hydraulic cylinder. In contrast to the first embodiment, when the optimum gain experimentally obtained in all speed ranges is not known, the same effect as the first embodiment can be obtained by setting only the upper limit value of the gain.

A side view of a tractor equipped with a rotary tiller concerning an embodiment of the present invention. The control block diagram of the tilling depth control which concerns on embodiment of this invention. The control block circuit diagram similarly. The figure showing the relationship between the vehicle speed and dead zone of the tilling depth control which concerns on the structural example 1 of this invention. The figure showing the relationship between the vehicle speed and gain of tilling depth control which concern on Example 1 of this invention. The figure showing the relationship between the vehicle speed and gain upper limit of the tilling depth control which concern on Example 2 of this invention.

1 Tractor 13 Tillage Device 14 Lift Arm 22 Rear Cover 32 Controller 34 Rear Cover Sensor

Claims (2)

  A sensor for detecting a tilling depth, a means for setting a tilling target value, a sensor for detecting a vehicle speed, and a lift arm (14) that is an actuator for raising and lowering a work implement are connected to a controller (32). In the plowing depth control mechanism of the tractor work machine that controls to the target depth set by the plowing depth setting means, the dead zone for the plowing depth target value is less than the set speed (A) on the low speed side. A predetermined narrow constant width, a predetermined wide constant width above the high speed set speed (C), and between a low speed set speed (A) and less than the high speed set speed (C). And an actuator that raises and lowers the work implement when the vehicle speed is less than the set speed (A) on the low speed side and above the set speed (C) on the high speed side. Lift arm ( 4) The control gain, which is the rotation speed, is a constant value, and is less than the intermediate set speed (B) set between the set speed (A) on the low speed side and the set speed (C) on the high speed side. Above the set speed (A) on the low speed side, the control gain increases in proportion to the increase in the vehicle speed, and when the speed is set above the intermediate set speed (B) and below the set speed (C) on the high speed side, the vehicle speed increases. A plowing depth control mechanism for a tractor working machine, wherein the control gain is reduced proportionally. A sensor for detecting a tilling depth, a means for setting a tilling target value, a sensor for detecting a vehicle speed, and a lift arm (14) that is an actuator for raising and lowering a work implement are connected to a controller (32). In the plowing depth control mechanism of the tractor work machine that controls to the target depth set by the plowing depth setting means, the dead zone for the plowing depth target value is less than the set speed (A) on the low speed side. A predetermined narrow constant width, a predetermined wide constant width above the high speed set speed (C), and between a low speed set speed (A) and less than the high speed set speed (C). And an actuator that raises and lowers the work implement when the vehicle speed is less than the set speed (A) on the low speed side and above the set speed (C) on the high speed side. Lift arm ( Upper limit of the speed is controlled gain rotating the 4) is a constant value, the intermediate set speed less than (B) which is set between the set speed of the low speed side of the set speed (A) and high-speed side (C) When the speed is higher than the set speed (A) on the low speed side, the upper limit value of the control gain is increased in proportion to the increase in the vehicle speed, and is higher than the set speed (C) on the high speed side at the intermediate set speed (B) or higher. Then, the working depth control mechanism of the tractor working machine, wherein the upper limit value of the control gain is decreased in proportion to the increase in the vehicle speed.

Images