JP2016123281A - Tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tractor that prevents a wrong abnormality determination of a draft sensor.SOLUTION: A tractor includes a traveling machine body 1 where a working machine is connected through a lifting/lowering link mechanism 2, draft sensors 12L, 12R for detecting a towing load of the working machine, and a draft automatic control function for automatically performing lifting/lowering control of the working machine on the basis of sensor values of the draft sensors 12L, 12R. The tractor includes draft sensor abnormality determination means for determining that the draft sensors 12L, 12R are abnormal when the sensor values of the draft sensors 12L, 12R are deviated from a normal range and a state deviated from the normal range exceeds a predetermined abnormality determination time T1. The draft sensor abnormality determination means delays the abnormality determination time T2 when the sensor values of the draft sensors 12L, 12R are deviated from the normal range by a load in the pushing direction.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a tractor including a draft sensor abnormality determination unit.

  As one of the automatic control functions provided in the tractor, there is known an automatic draft control for automatically raising and lowering the work implement based on a sensor value of a draft sensor that detects a traction load of the work implement (for example, plow) ( For example, see Patent Document 1). This type of tractor includes draft sensor abnormality determination means for determining abnormality of the draft sensor in order to prevent a reduction in work accuracy due to abnormality (failure) of the draft sensor, and is based on an alarm or the like based on the abnormality determination. Abnormality notification is performed.

Japanese Patent Laid-Open No. 5-292802

  However, the conventional draft sensor abnormality determination means determines that the draft sensor is abnormal when the sensor value of the draft sensor is out of the normal range and the state outside the normal range exceeds a predetermined abnormality determination time. Therefore, even if the sensor value of the draft sensor is out of the normal range due to the load in the pushing direction, there is a possibility that it is erroneously determined as an abnormal state. For example, when the machine is suddenly stopped with the work machine raised to the highest position, the load in the pushing direction is detected and the sensor value of the draft sensor is out of the normal range, which may cause an abnormality determination .

The present invention has been created in view of the above circumstances and has been created for the purpose of solving these problems. The invention of claim 1 includes a traveling machine body to which a work machine is connected via an elevating link mechanism. A tractor comprising a draft sensor for detecting a traction load of the work implement and a draft automatic control means for automatically raising and lowering the work implement based on a sensor value of the draft sensor, wherein the sensor value of the draft sensor is normal A draft sensor abnormality determining means for determining that the draft sensor is abnormal when a state outside the normal range and a state outside the normal range exceeds a predetermined abnormality determination time; When the sensor value of the draft sensor is out of the normal range due to a load in the direction, the abnormality determination time is delayed.
The invention of claim 2 is characterized in that, in the tractor according to claim 1, the draft sensor abnormality determination means delays the abnormality determination time on condition that the elevating link mechanism is in the highest position. .
According to a third aspect of the present invention, in the tractor according to the first or second aspect, the draft sensor abnormality determining means is configured such that the elevating link mechanism is in the upmost state and the sudden stop in the forward direction or the reverse direction is performed. The abnormality determination time is delayed on condition that the vehicle is suddenly started.

According to the invention of claim 1, the draft sensor abnormality determination means delays the abnormality determination time when the sensor value of the draft sensor is out of the normal range due to the load in the pushing direction. Can be prevented. For example, when the machine is suddenly stopped with the work machine raised to the highest position, even if the sensor value of the draft sensor falls outside the normal range due to the load in the pushing direction, an abnormality determination time longer than normal is applied. Therefore, it is not determined as abnormal.
Further, according to the invention of claim 2, since the abnormality determination time is delayed on the condition that erroneous abnormality determination is likely to be performed, that is, the lift link mechanism is in the highest state, the erroneous abnormality determination is prevented. However, normal abnormality determination can be performed quickly.
Further, according to the invention of claim 3, the situation in which erroneous abnormality determination is likely to be performed, that is, the lifting link mechanism is in the highest position and at the time of sudden stop in the forward direction or sudden start of the reverse direction. As a condition, the abnormality determination time is delayed, so that normal abnormality determination can be performed quickly while preventing erroneous abnormality determination.

It is a side view of a tractor. It is a top view of a tractor. It is a side view of a work machine connection part. It is a top view of a working machine connection part. It is a block diagram which shows the input / output of a control part. It is a flowchart which shows the process sequence of draft sensor abnormality determination.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2, reference numeral 1 denotes a traveling machine body of a crawler tractor, and various working machines (not shown) are connected to a rear portion of the traveling machine body 1 via a lifting link mechanism 2. As shown in FIGS. 3 and 4, the elevating link mechanism 2 is a three-point link mechanism including a single top link 6 and a pair of left and right lower links 7, and the left and right lower links 7 are respectively provided with lift rods 8. Is lifted by the lift arm 9, and the work implement is raised and lowered according to the vertical rotation of the lift arm 9 accompanying the hydraulic expansion and contraction operation of the lift cylinder 10.

  A pair of left and right lower link brackets 11 project from the rear portion of the traveling machine body 1, and the front end portions of the left and right lower links 7 are respectively connected to the left and right via draft sensors 12L and 12R that detect the traction load of the work implement. It is connected to the lower link bracket 11 so as to be rotatable up and down. As the draft sensor 12, for example, a strain sensor (load cell) that detects a strain amount of a connecting member that connects the lower link bracket 11 and the lower link 7 is used.

  As shown in FIG. 5, the traveling machine body 1 is provided with a control unit 13 configured using a microcomputer or the like. On the input side of the control unit 13, in addition to the left and right draft sensors 12L and 12R described above, a position sensor 14 for detecting the operation position of a position lever (not shown) for manually lifting and lowering the work implement, and a lift arm 9 Lift arm sensor 15 for detecting the vertical rotation position, depth setting volume 16 for setting a target depth for automatic depth control, depth work switching volume 17 for switching the work type of automatic depth control, automatic depth control An ON / OFF depth automatic switch 18 and a vehicle speed sensor 19 for detecting the vehicle speed of the traveling machine body 1 are connected. On the output side of the control unit 13, the alarm buzzer 20 and the lift cylinder 10 are moved upward. The ascending proportional control valve 21 to be operated, the descending proportional control valve 22 to operate the lift cylinder 10 downward, and the automatic depth control ON / OFF state. Such as Shimesuru depth automatic lamp 23 are connected.

  The control unit 13 realizes an automatic control function such as draft automatic control (draft automatic control means) by cooperation of hardware and software. The draft automatic control is an automatic control function for automatically raising and lowering the working machine based on the sensor values of the draft sensors 12L and 12R that detect the traction load of the working machine (for example, plow). The draft automatic control is executed by selecting the draft with the work switching volume 17 and turning on the depth automatic switch 18, and the target traction load (target depth) in the draft automatic control is adjusted with the depth setting volume 16. Is done.

  The control unit 13 includes draft sensor abnormality determination means for determining abnormality of the draft sensors 12L and 12R in order to prevent a decrease in work accuracy due to abnormality (failure) of the draft sensors 12L and 12R. On the basis of this, abnormality notification by the buzzer 20 or the like is performed.

  The draft sensor abnormality determination means determines that the draft sensors 12L and 12R are abnormal when the sensor values of the draft sensors 12L and 12R are out of the normal range and the state outside the normal range exceeds a predetermined abnormality determination time T1. Judge that there is. For this reason, even if the sensor values of the draft sensors 12L and 12R are out of the normal range due to the load in the pushing direction, there is a risk of erroneously determining that the state is abnormal. For example, when the machine is suddenly stopped with the work machine raised to the highest position, the load in the pushing direction is detected, and the sensor values of the draft sensors 12L and 12R are out of the normal range, and the abnormality may be determined. was there.

  Therefore, the draft sensor abnormality determination unit according to the embodiment of the present invention delays the abnormality determination time T2 when the sensor values of the draft sensors 12L and 12R are out of the normal range due to the load in the pushing direction. According to such a draft sensor abnormality determination means, for example, when the aircraft is suddenly stopped with the work machine raised to the highest position, the sensor values of the draft sensors 12L and 12R are within a normal range depending on the load in the pushing direction. Even if the deviation is outside, the abnormality determination time T2 that is longer than usual is applied, so that it is not determined as abnormal.

  Further, the draft sensor abnormality determination means of the present embodiment delays the abnormality determination time T2 on condition that the elevating link mechanism 2 is in the highest position. Therefore, since the abnormality determination time T2 is delayed only in a situation where erroneous abnormality determination is likely to be performed, that is, when the lifting / lowering link mechanism 2 is in the highest position, normal abnormality determination is performed quickly while preventing erroneous abnormality determination. be able to.

  Furthermore, in the draft sensor abnormality determination means of the present embodiment, the abnormality determination time T2 is set on condition that the lifting / lowering link mechanism 2 is in the highest lifted state and is suddenly stopped in the forward direction or suddenly started in the reverse direction. Delay. Therefore, the error determination time T2 is delayed only when the erroneous abnormality determination is likely to be performed, that is, when the lifting / lowering link mechanism 2 is in the highest position and when the forward movement is suddenly stopped or the backward movement is suddenly started. The normal abnormality determination can be quickly performed while preventing the abnormality determination. Hereinafter, the draft sensor abnormality determination processing procedure for realizing such draft sensor abnormality determination means will be described with reference to the flowchart shown in FIG.

As shown in FIG. 6, in the draft sensor abnormality determination of the present embodiment, first, it is determined whether or not the sensor values of the draft sensors 12L and 12R are within a normal range (S1), and if this determination result is NO, In other words, when it is determined that the sensor values of the draft sensors 12L and 12R are out of the normal range, the direction of removal is determined (S2). When this determination result is in the pulling direction, the duration time of the disengaged state is measured, and it is determined whether or not this duration time has exceeded the abnormality determination time T1 (S3), and this determination result is YES The draft sensors 12L and 12R are determined to be abnormal, and a predetermined abnormality determination process (S4) is executed.

  On the other hand, if the determination result in step S2 is the push direction, it is determined whether or not the work implement is in the highest lifted state based on the sensor value of the lift arm sensor 15 (S5), and the determination result is NO. Is shifted to the determination in step S3 (abnormality determination based on the abnormality determination time T1) in the same manner as in the case of deviating in the pulling direction, but if it is determined that the work implement is in the highest state, the sensor value of the vehicle speed sensor 19 Based on the above, it is determined whether or not it is at the time of forward sudden stop or at the time of reverse sudden start (S6, S7). If it is determined that the vehicle is neither forward sudden stop nor reverse sudden start, the process proceeds to the determination of step S3 (abnormality determination based on the abnormality determination time T1) as in the case of moving away from the pulling direction. If it is determined that the vehicle is suddenly stopped or the vehicle is suddenly started backward, abnormality determination is performed based on the abnormality determination time T2 delayed from the abnormality determination time T1 (S8).

  According to the present embodiment configured as described, the traveling machine body 1 to which the work machine is connected via the lifting link mechanism 2, the draft sensors 12L and 12R for detecting the traction load of the work machine, the draft sensor 12L, A tractor having a draft automatic control function for automatically raising and lowering the work implement based on the sensor value of 12R, wherein the sensor values of the draft sensors 12L and 12R are out of the normal range and out of the normal range Is provided with draft sensor abnormality determination means for determining that the draft sensors 12L and 12R are abnormal when the predetermined abnormality determination time T1 is exceeded. The draft sensor abnormality determination means includes the draft sensor 12L, If the sensor value of 12R is out of the normal range, the abnormality determination time T2 is delayed, so the draft sensors 12L and 12R are erroneous. It is possible to prevent abnormal determination. For example, when the machine is suddenly stopped with the work machine raised to the highest position, even if the sensor values of the draft sensors 12L and 12R are out of the normal range due to the load in the pushing direction, the abnormality determination time is longer than usual. Since T2 is applied, it is not determined to be abnormal.

  Further, the draft sensor abnormality determination unit of the present embodiment is in a situation where erroneous abnormality determination is easily performed, that is, when the elevating link mechanism 2 is in the highest position, and when suddenly stopping in the forward direction or suddenly starting in the reverse direction Since the abnormality determination time T2 is delayed on the condition that it is, normal abnormality determination can be performed quickly while preventing erroneous abnormality determination.

DESCRIPTION OF SYMBOLS 1 Traveling machine body 2 Lifting link mechanism 12L, 12R Draft sensor 13 Control part 15 Lift arm sensor 19 Vehicle speed sensor 20 Buzzer

Claims (3)

A traveling machine body to which a work machine is connected via an elevating link mechanism;
A draft sensor for detecting the traction load of the work implement;
A tractor comprising draft automatic control means for automatically raising and lowering the work implement based on the sensor value of the draft sensor;
A draft sensor abnormality determining means for determining that the draft sensor is abnormal when a sensor value of the draft sensor is out of a normal range and a state outside the normal range exceeds a predetermined abnormality determination time; The draft sensor abnormality determining means delays the abnormality determination time when the sensor value of the draft sensor is out of a normal range due to a load in the pushing direction.   2. The tractor according to claim 1, wherein the draft sensor abnormality determination unit delays the abnormality determination time on condition that the lifting / lowering link mechanism is in a fully up state.   The draft sensor abnormality determination means delays the abnormality determination time on the condition that the elevating link mechanism is in the highest position and is in a sudden stop in the forward direction or a sudden start in the reverse direction. The tractor according to claim 1 or 2.

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