JP2007049925A - Automatic controller for tilling depth for tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic controller for tilling depth of the tractor that can stabilize the actual value to the same set value regardless the height of the rotary tilling device to the tractor. <P>SOLUTION: The connection-changing means is provide to change the interlocking condition between the rear cover 19 and the hydraulic pressure controlling mechanism 10 by interlocking with the vertical rocking of the lift arm 4, and, when they are maintained stably at the same tilling depth, the attitude of the rear cover 19 is connected to the vertical rocking attitude of the lift arm 4, so that the attitude of rocking displacement may move to the rotary cover 18 downward, as the lift arm 4 is rocked more upward. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  According to the present invention, a rotary tiller is connected to a rear portion of a tractor via a link mechanism that is driven up and down by a lift arm, and a rear cover that can swing up and down is attached to a rear end portion of a rotary cover provided in the rotary tiller. And an automatic plowing depth control device for a tractor configured to operate a hydraulic control mechanism on the basis of a swinging displacement of a rear cover to control lifting and lowering of a lift arm.

  Since the rotary tiller is generally connected via a link mechanism having a three-point link structure or a two-point link structure, the rotary tiller is inclined forward as it is raised. For this reason, in the above automatic tilling control in which the swinging posture of the rear cover is controlled to a set angle with respect to the rotary cover, even if the set tilling depth is the same, the actual tilling depth differs depending on the swinging posture of the lift arm. Will occur.

  For example, as shown in FIG. 3, when the rotary tiller 3 is connected to the rear part of the tractor via the link mechanism 2 having a two-point link structure, the lift arm 4 is in a low posture as shown in FIG. At a certain time, the tilling depth d1 for making the posture of the rear cover 19 with respect to the rotary cover 18 a predetermined posture, and the rear with respect to the rotary cover 18 when the lift arm 4 is in a high posture as shown in FIG. When compared with the tilling depth d2 for changing the posture of the cover 19 to a predetermined posture, the tilling depth d2 when the lift arm 4 is in a high posture and the rotary tiller 3 is tilted forward becomes larger.

  Therefore, because the tractor is likely to sink in fields with a lot of moisture, the rotary tiller will be used at a higher position relative to the tractor than when there is no settlement. The actual plowing depth with respect to the plowing depth is greater when there is subsidence than when there is no subsidence. In addition, in a field with a lot of moisture, there is little swelling of the soil of the tillage and it is difficult to cause the upper displacement of the rear cover due to the swelling of the soil, so it is difficult to perform lift control based on the upward swing of the rear cover, There is a tendency for the actual tilling depth to become larger.

  Therefore, the rotary cover that pivotally connects the rear cover is configured so that it can be rotated back and forth around the rotor shaft center, so that the rotary cover can be moved with respect to the field regardless of changes in the front and back tilt posture of the entire rotary tiller. Means have been proposed in which the above-mentioned problems can be solved by correcting to a predetermined posture (see, for example, Patent Document 1).

JP-A-8-214610

  According to the above-mentioned means shown in Patent Document 1, when the rotary tiller is lifted and used with respect to the tractor, the rotary cover is tilted forward and the rotary cover is rotated backward. Thus, it is possible to stabilize the actual tilling depth when the lifting control is performed so as to maintain the swinging posture of the rear cover with respect to the rotary cover regardless of the height of the rotary tiller with respect to the tractor. It is necessary to manually adjust the position of the rotary cover in accordance with the inclined position of the rotary tiller, which makes the operation troublesome and makes it difficult to perform desired performance if the adjustment amount is incorrect. Moreover, the structure which mounts | wears with a rotary cover so that rotation adjustment is possible back and forth is required, and the cost of a rotary tiller itself will also be caused.

  The present invention has been made paying attention to such points, and it is possible to stabilize the actual tillage depth for the same set tillage depth regardless of the height of the rotary tiller with respect to the tractor. The main purpose.

In the first aspect of the present invention, a rotary tiller is connected to a rear portion of a tractor via a link mechanism that is driven up and down by a lift arm, and the rear end portion of a rotary cover provided in the rotary tiller can swing up and down. In the automatic tiller control device for a tractor configured to connect the rear cover and operate the hydraulic control mechanism based on the swing displacement of the rear cover to control the lift arm to move up and down,
Linkage changing means for changing the linkage state between the rear cover and the hydraulic control mechanism in conjunction with the vertical swing of the lift arm is provided, and the posture of the rear cover when the stable setting is maintained at the same setting depth The lift arm's up-and-down swing position is linked to the rear cover position so that the position of the lift arm swings downward relative to the rotary cover as the position of the rear cover swings upward. To do.

  According to the above configuration, when the lift arm is swung upward, that is, when the rotary tiller device is lifted high with respect to the tractor, the rotary tiller device is tilted forward. The posture of the cover with respect to the rotary cover is automatically corrected to a posture in which the rear cover swings downward relative to the posture of the rear cover with respect to the rotary cover when the lift arm is not swinged upward. The height (actual tilling depth) from the lower end to the rear end grounding point of the rear cover is smaller than when the automatic correction is not performed. That is, the increase in tilling depth accompanying the forward inclination of the rotary tiller is suppressed.

  Therefore, according to 1st invention, regardless of the height with respect to the tractor of a rotary tiller, the actual tilling depth with respect to the same setting tillage depth was able to be stabilized now. In addition, since an artificial adjustment operation is not necessary, there is no risk of forgetting an adjustment or an adjustment error, and the desired automatic tilling control can always be performed satisfactorily.

According to a second invention, in the first invention,
The rear cover and the hydraulic control mechanism are interlocked and connected by a release type sensor wire, and the outer end portion of the sensor wire is displaced in the wire operating direction in conjunction with the vertical swing of the lift arm. Is.

  According to the above configuration, the desired automatic adjustment can be mechanically performed by effectively utilizing the structure of the sensor wire, and the first invention can be suitably implemented.

According to a third invention, in the second invention,
An operating arm that swings integrally with the lift arm is provided at the base of the lift arm, and the outer end of the front of the sensor wire is supported on the operating arm.

  According to the above configuration, generally, a structure in which a wire bracket for supporting the front outer end portion of the sensor wire is fixed to an appropriate position of the tractor, and the front end portion of the sensor wire in the operating arm swinging integrally with the lift arm is provided. The desired automatic adjustment can be mechanically performed only by changing to a simple structure that supports the above, and the features of the second invention can be exhibited more remarkably.

A fourth invention is the invention according to any one of the first to third inventions,
The link mechanism has a two-point link structure that connects and supports a rotary tiller so that it can swing up and down around one point.

  According to the above configuration, if the rotary tiller is supported via the link mechanism of the two-point link structure, the tilting posture at the front and rear of the rotary tiller greatly changes due to the vertical swing of the lift arm, and the actual tillage depth Can easily vary, so that the effects of the present invention can be exhibited particularly effectively.

  FIG. 1 shows a side view of an agricultural tractor constructed to the rotary tillage specification. This agricultural tractor has a rotary tiller 3 connected to the rear part of a four-wheel tractor main body 1 via a link mechanism 2, and a pair of left and right lift arms 4 arranged above the rear part of the tractor 1 are incorporated in a lift cylinder. The rotary tiller 3 can be moved up and down by driving up and down at 5.

  The link mechanism 2 can swing a support arm 8 projecting forward from the rotary case 7 of the rotary tiller 3 to a hitch 6 provided at the rear end of the contactor 1 at a single point around a lateral fulcrum P. The left and right lift arms 4 and the support arms 8 are respectively connected by lift rods 9.

  The lift cylinder 5 is a single-acting hydraulic cylinder that is extended by the supply of pressure oil to drive and lift the lift arm 4 and is shortened by draining oil to lower the lift arm 4 by its own weight. The mechanism 10 is connected in communication.

  Although a detailed structure is omitted, as shown in FIG. 2, the hydraulic control mechanism 10 includes a mechanical position control valve (not shown). The position control valve includes a position lever 12, and The auto lever 13 is linked. In this hydraulic control mechanism 10, position control for moving the rotary tiller 3 to the height set by the position lever 12, and automatic tilling that stably maintains the rotary tiller 3 at the set tilling depth set by the auto lever 13. It is possible to execute deep control, and the outline of each control will be described below.

  "Position control"

  In the position control, the position lever 12 is operated and held at an arbitrary height position while the auto lever 13 is operated and held at the frontmost deepest position (automatic cutting). When the position lever 12 is operated backward (shallow) or forward (deep), the position control valve is switched, the lift cylinder 5 is raised or lowered, the lift arm 4 is fed back, and the position control valve is neutral. When the lift arm 4 reaches a height corresponding to the operation position of the position lever 12, the position control valve returns to neutral and the lifting operation is stopped. That is, in this “position control”, the rotary tiller 3 can be moved and fixed to an arbitrary height set by the position lever 12.

  "Automatic depth control"

  In the automatic tilling depth control, the set tilling depth as a reference is set by operating the auto lever 13, and the actual tilling depth of the rotary tilling device 3 is mechanically detected, and the detected actual tilling depth is set as the set tilling depth. When the position is deviated from the range, the position control valve is operated in a direction to correct this, and the actual tilling depth of the rotary tiller 3 is mechanically detected as follows.

  The rotary tiller 3 is equipped with a tilling rotor 17 in which a number of tilling claws 16 are attached to a rotor shaft 15 at a lower portion of a rotary case 7 that receives working power taken out from the tractor 1. A rotary cover 18 that covers an upper portion of the rotary cover 17 is fixed to the rotary case 7, and a rear cover 19 is connected to a rear end portion of the rotary cover 18 so as to be swingable up and down around a fulcrum q. 19 is configured to be rocked and biased downward by a pressing spring 20 so as to press down the tillage with an appropriate force to reduce the pressure.

  The rear cover 19 has a function as a grounding sensor for plowing depth detection in “automatic plowing depth control”, and a lower end of a detection arm 21 provided on the upper surface of the rotary cover 18 so as to be swingable around a fulcrum r. And the rear cover 19 are linked together via a link 22 and the inner rear end of a sensor wire 23 using a release wire is connected to the upper end of the detection arm 21.

  The outer rear end portion 23r of the sensor wire 23 is fixedly supported by a wire bracket 24 provided on the upper portion of the rotary case 7, and when the rear cover 19 swings upward when the working depth becomes deep, the inner portion of the sensor wire 23 is increased. When the rear end is pulled out rearward and the tilling depth becomes shallow and the rear cover 19 swings downward, the inner rear end of the sensor wire 23 is pulled forward. That is, a change in the actual tilling depth is detected as an inner displacement in the sensor wire 23 and is transmitted to the sensor arm 25 of the hydraulic control mechanism 10.

  When executing the automatic tilling control, the auto lever 13 is operated and held at an arbitrary depth position with the position lever 12 being switched and held at the foremost position. Here, the position lever 12 is not related to the elevation control because the mechanical linkage with the position control valve is cut off.

  When the auto lever 13 is operated to an arbitrary height position deviated rearward from the deepest position (automatic cutting), the set working depth is determined corresponding to the operation position. By operating the auto lever 13 rearward from the deepest position (automatic cutting), the sensor arm 25 is linked to the position control valve, and the actual tilling depth detected by the swing of the rear cover 19 is the auto lever 13. If it is deeper than the set tilling depth set in step S1, the inner front portion of the sensor wire 23 is displaced rearward to operate the sensor arm 25 ascending, and conversely, the detected actual tilling depth is greater than the set tilling depth. If it is shallow, the inner front portion of the sensor wire 23 is displaced forward, so that the sensor arm 25 is operated downward, so that the actual tilling depth is always stably maintained at the set tilling depth (including the dead zone). .

  Here, the front outer end 23f of the sensor wire 23 is automatically adjusted in the wire operating direction in accordance with the posture of the lift arm 4. In other words, an operating arm 26 that swings integrally with the lift arm 4 is provided downward at the base of the lift arm 4, and a front outer end 23 f of the sensor wire 23 is connected to and supported by the distal end of the operating arm 26. Has been.

  In this configuration, when the set tilling depth set by the auto lever 13 is the same, the state in which the lift arm 4 is lowered and the automatic tilling control is performed is compared with the case where the lift arm 4 is raised and the automatic tilling control is performed. It is shown in FIG.

  As shown in FIG. 2 (b), when the lift arm 4 is swung upward, that is, when the rotary tiller 3 is lifted high with respect to the tractor 1, the attitude of the rotary tiller 3 is forward. However, the upper outer end 23f of the sensor wire 23 is displaced more backward than when the lift arm is lowered as shown in FIG. The posture of the rear cover 19 relative to the rotary cover 18 at the time of neutral control is automatically corrected to a posture that swings downward from the posture of the rear cover 19 relative to the rotary cover 18 in the case shown in FIG. The height (actual tilling depth) d from the lower end of the tilling rotor 17 to the rear end grounding point of the rear cover 19 is smaller than that when the outer end portion 23f is fixed in position (see FIG. 3B). The casting. That is, even if the height of the lift arm 4 changes and the forward inclination of the rotary tiller 3 changes, the actual tilling depth d corresponding to the same set tilling depth is substantially constant.

  [Other Examples]

  (1) Although the position of the outer end 23f in front of the sensor wire 23 is adjusted in conjunction with the lifting and lowering of the lift arm 4 in the above embodiment, the position of the outer end 23r behind the sensor wire 23 is automatically adjusted. The same function can be exhibited.

  (2) As a means for detecting the vertical swing of the lift arm 4, in addition to extending the operating arm 26 from the lift arm 4 as described above, the relative angle change between the lift arm 4 and the lift rod 9, the lift rod It is also possible to use two members whose relative postures change as the rotary tiller 3 moves up and down, such as a relative angle change between 9 and the support arm 8 and a relative angle change between the hitch 6 and the support arm 8.

  (3) The swinging angle of the rear cover 19 is detected by an angle sensor such as a potentiometer to detect the actual tilling depth, and the detected information is transmitted to the hydraulic control device 10 including an electromagnetic control valve for automatic tilling control. The present invention can be applied to the form to be performed. In this case, by detecting the swing position of the lift arm 4 with an angle sensor such as a potentiometer and adjusting and changing the detected angle information of the rear cover 19 based on the detection result, the same function as described above can be exhibited. it can.

  (4) Even in a specification in which the link mechanism 2 adopts a three-point link structure including a top link and a lower link, the tilt posture of the rotary tiller 3 changes depending on the swing position of the lift arm 4 and the two-point link. As in the case of the structure, since the actual tillage depth with respect to the same set tillage depth changes, if the present invention is applied, the change in the actual tillage depth with respect to the same set tillage depth can be reduced regardless of the height of the lift arm 4. it can.

Whole side view of agricultural tractor Side view showing the state of automatic tilling control with different lift arm heights Side view showing an automatic tilling control state with different lift arm heights according to the conventional structure

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tractor 2 Link mechanism 3 Rotary plowing device 4 Lift arm 10 Hydraulic control mechanism 23 Sensor wire 23f Outer end part 26 Actuating arm

Claims (4)

A rotary tiller is connected to the rear part of the tractor via a link mechanism that is driven up and down by a lift arm, and a rear cover is connected to the rear end of the rotary cover provided in the rotary tiller so that it can swing up and down. In the automatic tiller control device for a tractor configured to operate the hydraulic control mechanism based on the swing displacement of the rear cover to control the lift arm to move up and down,
Linkage changing means for changing the linkage state between the rear cover and the hydraulic control mechanism in conjunction with the vertical swing of the lift arm is provided, and the posture of the rear cover when the stable setting is maintained at the same setting depth The lift arm's up-and-down swing position is linked to the rear cover position so that the position of the lift arm swings downward relative to the rotary cover as the position of the rear cover swings upward. Automatic tiller control device for tractors.   The rear cover and the hydraulic control mechanism are interlocked and connected by a release type sensor wire, and the outer end portion of the sensor wire is displaced in the wire operating direction in conjunction with the vertical swing of the lift arm. The automatic tilling depth control device for a tractor according to claim 1.   The automatic tiller control device for a tractor according to claim 2, wherein an operating arm that swings integrally with the lift arm is provided at a base portion of the lift arm, and a front outer end portion of the sensor wire is supported on the operating arm.   The automatic tilling depth control device for a tractor according to any one of claims 1 to 3, wherein the link mechanism is constituted by a two-point link mechanism that connects and supports a rotary tilling device so as to swing up and down around one point.

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