JPH0738762B2 - Working equipment lifting operation structure for work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a hydraulic cylinder for moving a working device up and down with respect to a traveling body, and a first direction for detecting an operating direction and an operating stroke of an operating tool for lifting a working device. A sensor and a second sensor for detecting the height of the working device with respect to the traveling machine body are provided, and the working device is moved up and down by a stroke proportional to the operation stroke of the operating tool as the operating tool is operated. The present invention relates to a work device lifting / lowering operation structure for a work vehicle, which is provided with position control means for automatically operating the hydraulic cylinder based on the detection results of the first sensor and the second sensor.

[Conventional technology]

In the above-mentioned work vehicle, when the work device descends due to oil leakage in the hydraulic circuit for the hydraulic cylinder, the detection result of the second sensor changes due to the work device descending.
The raising control for correcting the height of the work device to the height corresponding to the detection result of the first sensor is automatically performed, but no measure has been taken for this correction control.

[Problems to be Solved by the Invention]

Conventionally, when oil leakage occurs, the work device height correction control is performed relatively frequently, the number of times the cylinder control valve is switched increases, and the control valve and the constituent members of its operating structure are quickly worn away. Problems such as the above were likely to occur.

It is an object of the present invention to avoid the above-mentioned troubles while allowing normal raising and lowering operations by position control to be performed without any hindrance.

[Means for Solving the Problems]

In order to achieve the object, according to the present invention, in the work device lifting operation structure for a work vehicle described above, it is preferable that the detection result of only the second sensor of the first sensor and the second sensor is changed to the descending side. A work device lowering detection means for detecting is provided, and when the work device lowering detection means is in a detection state, it automatically operates, and a temporary dead zone wider than the normal dead zone is set in the position control means instead of the normal dead zone. A dead zone changing means is provided, which automatically operates when the position control means starts the cylinder raising operation operation based on the detection results of the first sensor and the second sensor and the temporary dead zone, and the normal dead zone. Is reset to the temporary dead zone, and the cylinder raising operation operation is performed to the position control until the height detected by the second sensor falls within the normal dead zone. Means for performing dead zone resetting means, or the position control means performs a hydraulic cylinder raising operation operation due to a change in the detection result of only the second sensor of the first sensor and the second sensor. An abnormal control detection means for detecting the start is provided, and when the abnormal control detection means is in the detection state, it automatically operates,
The temporary control target height higher than the positive control target height based on the detection result of the first sensor, and the normal control target height while entering the normal dead zone in a state based on the positive control target height The reference temporary dead band is set in place of the control target height and the normal dead band, and the position control means is made to perform the cylinder raising operation until the height detected by the second sensor falls within the temporary dead band. A control form changing means is provided, and when the height detected by the second sensor enters the temporary dead zone and the position control means performs a cylinder stop operation, the position control means automatically operates, and the position control means controls the target height and the height. A control form resetting means for resetting the normal dead zone in place of the temporary control target height and the temporary dead zone is provided.
The action and effect are as follows.

[Work]

When the cause of the work device raising / lowering control is human operation, the detection result by the first sensor changes, and when there is oil leakage, the detection result by the first sensor does not change and only the detection result by the second sensor changes. To do. Therefore,
During manual operation, in the first invention, the work device lowering detection means is in the non-detection state and the dead zone changing means does not operate, and in the second invention, the abnormal control detection means is in the non-detection state and the control form changing means operates. In any of the inventions, only the normal dead zone is set, and the cylinder actuation operation and the cylinder stop are all performed under the normal dead zone. When the oil leaks, in the first invention, the working device lowering detection means is in the detection state and the dead zone changing means is activated to set the temporary dead zone, and the detection height by the second sensor falls below the temporary dead zone. For the first time, the position control means starts the rise correction control, and the dead zone resetting means is activated accordingly, and the normal dead zone is reset, and the detected height returns to the height within the normal dead zone. Is corrected up to. In the second aspect of the invention, when the detected height falls below the normal dead zone, the position control means starts the ascending correction control, and along with this, the abnormal control detecting means enters the detecting state and the control form changing means operates. By operating, the temporary control target height and the temporary dead zone are set, and the rising correction is performed until the detected height reaches the height within the temporary dead zone. Therefore, in any of the inventions, even if the rising correction control is repeated due to oil leakage, compared to the conventional constant dead zone configuration in which only the normal dead zone is set, the human-controlled operation is performed. Sometimes it is possible to make fine adjustment as much as possible and to make hunting less likely to occur as much as possible, but for that reason, it is necessary to make the repetitive correction with a longer cycle, the width difference between the normal dead zone and the temporary dead zone and the positive control. It is possible because of the difference between the target height and the temporary control target height.

〔The invention's effect〕

Due to the combination of the work device lowering detection means, the abnormality control detection means, the dead zone changing means, the control form changing means, the dead zone resetting means and the control form resetting means, oil leakage occurs and the work equipment height correction control is performed. Even if it is repeated, the frequency of control valve switching for that purpose is relatively low, wear of members is less likely to occur, and long-term use becomes possible.

〔Example〕

 Next, examples will be shown.

As shown in FIG. 7, a rotary tiller (3) is connected to the rear part of the wheel traveling body so as to be vertically moved by a hydraulic cylinder (1) via a link mechanism (2) which is vertically swingable, and The cultivator is configured so that power is transmitted from the traveling machine body to the cultivating device (3) by the rotating shaft (4).

The potentiometer-type first sensor (6) is interlocked with the operation tool (5) so as to detect the operation direction and operation stroke of the lever-type operation tool (5) provided on the traveling machine body and to electrically extract the detection result, The second potentiometer-type sensor (7) for detecting the height of the tiller (3) with respect to the traveling vehicle body and for electrically extracting the detection result is used as a swing angle of the lift arm (2a) that constitutes the link mechanism (2). It is interlocked with the lift arm (2a) so as to perform a predetermined detection based on. Then, as shown in FIG. 1, the first sensor (6) is connected to the electromagnetic control valve (V) of the hydraulic cylinder (1) through the control target height setting means (8) and the position control means (9). The second sensor (7) is linked to the position control means (9) while being linked to the drive circuit (10),
The cultivating device (3) is moved up and down while controlling the position by swinging the operating tool (5).

That is, the operation tool (5) is operated and the first sensor (6) is operated.
When the result of detection by the control target changes, the control target height setting means (8) automatically calculates the height at which the tilling device (3) should be positioned based on the information from the first sensor (6) and the calculated height. It is configured to be set as the control target height. The position control means (9) includes a comparison / determination means (11), a rising control means (12), and a neutral control means (13).
And a descent control means (14), and a comparison and determination means (11) compares the set control target height by the control target height setting means (8) with the detection height by the second sensor (7). Is configured to discriminate the difference, and the comparison control means (11) outputs a discrimination result that the detected height is equal to or substantially equal to the set control target height, the rising control means (12), the neutral control Each of the means (13) and the descending control means (14) raises the control valve (V) by outputting a predetermined control valve operation signal to the drive circuit (10) based on the discrimination result by the comparison discrimination means (11). It is configured to operate to a position or a neutral position or a lowered position. That is, as the operating tool (5) is operated, the tilling device (3) is actuated to the ascending side or the descending side corresponding to the operating tool operating direction, and the ascending or descending stroke of the tilling device (3) is operated. The position control means (9) includes a first sensor (6) and a second sensor (7) so that the tiller (3) stops when reaching a value proportional to the tool operation stroke.
The hydraulic cylinder (1) is automatically operated on the basis of the detection result of.

Cultivator descent detection means (1) for detecting the descent of the tiller (3) due to oil leakage in the hydraulic circuit of the hydraulic cylinder (1).
5) through the dead zone changing means (16) to compare and determine means (1
1), the temporary dead zone setting means (17) and the dead zone resetting means (18) are linked to the comparing and judging means (11), and the lifting operation using the operation tool (5) is relatively finely adjusted. Although it is possible and in a good control state in which control hunting is less likely to occur, consideration is given to reduce the frequency of correction control performed by lowering the tiller (3) due to oil leakage. .

That is, the lever position storage means (19) includes the first sensor (6) in view of the fact that the lift arm (2a) is displaced without displacing the operating tool (5) when the descent of the tiller is caused by an oil leak. The operation position where the operation tool (5) is present is stored based on the detection result by the device, and the storage position is updated every time the position control means (9) performs a cylinder stop operation. , Tillage device descent detection means (15)
Is a second sensor (7) of the first sensor (6) and the second sensor (7) based on the information from the first sensor (6), the second sensor (7) and the lever position storage means (19). It is configured to detect that the oil leakage of the tiller (3) has occurred by detecting that the detection result of the chisel has changed to the descending side. Then, when the tilling device descending detection means (15) enters the detection state, the dead zone changing means (16) automatically operates, and the dead zone setting means based on the normal dead zone setting means (20) is replaced with the temporary dead zone setting means. By making the comparison / discrimination means (11) perform the dead zone setting based on (17), the third zone which is wider than the normal dead zone (A) as shown in FIG.
The temporary dead zone (B) as shown in FIG. 3C is set by the control target height setting means (8) as the setting control target height, and is set by the position control means (9) instead of the normal dead zone (A). Is configured. When the position control means (9) starts the cylinder raising operation operation based on the detection results of the first sensor (6) and the second sensor (7) and the temporary dead zone (B), the dead zone reset means (18). Automatically operates and the dead zone for normal use (A)
Is set to the set control target height by replacing the temporary dead zone (B) with the comparison and determination means (11) and resetting it until the height detected by the second sensor (7) falls within the normal dead zone (A). The position control means (9) is configured to perform a raising operation.

In other words, at the time of manual operation, the detection result by the first sensor (5) changes, so that the tilling device lowering detection means (15) becomes non-detection state and the dead zone changing means (16) does not operate, and the position control means ( 9) sets only the normal dead zone (A), and the cylinder operating operation is started when the detected height (Z) deviates from the normal dead zone (A) as shown in FIG. When the detected height (Z) enters the normal dead zone (A) as shown in (e), the cylinder is stopped. Then, when the tiller (3) descends due to oil leakage, the tiller descending detection means (15) enters a detection state and the dead zone changing means (16) operates, and as shown in FIG. 3 (c). A temporary dead zone (B) is set. When the detected height (Z) falls below the temporary dead zone (B) as shown in FIG. 3D, the cylinder raising operation is started and the dead zone resetting means ( 18) is activated and the normal dead zone (A) is reset, and the correction control is stopped when the detected height (Z) enters the normal dead zone (A) as shown in Fig. 3 (e) due to cylinder operation. Is done.

[Another embodiment]

In the operating structure shown in FIG. 2, the abnormal control detecting means (21) is replaced by the control form changing means (22) in place of the tiller lowering detecting means (15) of the embodiment structure shown in FIG. By operating the determination means (11) and the temporary control target height setting means (23), the temporary dead zone setting means (17) and the control form resetting means (24) to the comparison determining means (11) In the case of the structure shown in Fig. 1 so that the frequency of the correction lifting control due to oil leakage is reduced, even though the lifting operation using the tool (5) can be performed in the good control state. We are trying to make it even more effective.

That is, when the abnormal control detection means (21) enters the detection state, the control mode changing means (22) automatically operates, and the control target height setting based on the control target height setting means (8) is performed. Instead, the control target height setting based on the temporary control target height setting means (23) and the dead zone setting based on the normal dead zone setting means (20) are replaced by the temporary dead zone setting means (17). By making the comparison / determination means (11) perform the dead zone setting at that time, the fourth determination based on the detection result of the first sensor (6) is performed.
The temporary control target height (Y) as shown in FIG. 4 (c), which is higher than the positive control target height (X) as shown in FIG.
Also, the normal control target height (X) is used as a reference to enter the normal dead zone (A) higher than the positive control target height (X), and the temporary control target height (Y) is used as a reference. The temporary dead zone (D) as shown in FIG. 4C is set in place of the positive control target height (X) and the normal dead zone (A), and the cylinder is set until the detected height enters the temporary dead zone (D). The position control means (9) is configured to perform a raising operation. Then, when the detected height enters the temporary dead zone (D) and the position control means (9) performs a cylinder stop operation, the control mode resetting means (24) automatically operates, and the temporary control target height (Y) and Instead of the temporary control target height (Y), the control target height (X) and the normal dead zone (A) are reset by the position control means (9).

That is, at the time of human operation, since the detection result by the first sensor (6) changes, the abnormality control detection means (21) is in a non-detection state, the control mode changing means (22) does not operate, and the position control means (21 9) sets only the positive control target height (X) and the normal dead zone (A), and the detected height (Z) deviates from the normal dead zone (A) as shown in FIG. When the operation operation is started and the detected height (Z) enters the normal dead zone (A), the cylinder stop operation is performed. Then, due to oil leakage, the tiller (3) descends, and the detected height (Z) descends beyond the normal dead zone (A) as shown in FIG. When the cylinder raising operation by the means (9) is started, the abnormal control detection means (21) enters the detection state, so the control mode changing means (22) operates and the temporary control is performed as shown in FIG. 4 (c). When the target (Y) and the temporary dead zone (D) are set and the detected height (Z) enters the temporary dead zone (D) as shown in FIG. 4 (D) with the cylinder operation, the correction control is stopped and The control mode resetting means (24) is operated to reset the normal control target height (X) and the normal dead zone (A) as shown in FIG.

Various means such as the position control means (9) and the control target height setting means (8) shown in FIGS. 1 and 2 are constituted by a microcomputer, and the operation structure shown in FIG. Based on the flowchart shown in FIG.
In the operation structure shown in the figure, each is automatically operated based on the flowchart shown in FIG.

The present invention can be applied to an elevating operation structure such as a trencher other than the tilling device, and also to an elevating operation structure of the harvesting pretreatment section of the combine. Therefore, the tilling device (3) is referred to as a working device (3), and the tilling device lowering detecting means (15) is referred to as a working device lowering detecting means (15).

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

1 and 2 are block diagrams of a control system, and FIG.
Figures 3 (a) to (e) and Figures 4 (a) to (e)
Is an explanatory view of the dead zone, FIGS. 5 and 6 are flowcharts, and FIG. 7 is a side view of the rear part of the tiller. (1) …… hydraulic cylinder, (3) …… working device, (5)
...... Operating tool, (6) ...... First sensor, (7) ...... Second sensor, (9) ...... Position control means, (15) ...... Tilling device lowering detection means, (16) ...... Dead zone change Means, (18)
...... Dead band resetting means, (21) ...... Abnormal control detecting means, (22) ...... Control form changing means, (24) ...... Control form resetting means, (A) ...... Normal use dead band, (B),
(C), (D) ... temporary dead zone, (X) ... normal control target height, (Y) ... temporary control target height, (Z) ... detection height.

Claims (2)

[Claims] 1. A first sensor (6) for detecting an operating direction and an operating stroke of a hydraulic cylinder (1) for raising and lowering a working device (3) with respect to a traveling machine body, and an operating tool (5) for raising and lowering the working device. And a second sensor (7) for detecting the height of the working device (3) with respect to the traveling machine body, and is proportional to the operation stroke of the operation tool (5) in accordance with the operation of the operation tool (5). Position control means (9) for automatically operating the hydraulic cylinder (1) based on the detection results of the first sensor (6) and the second sensor (7) while the working device (3) moves up and down the stroke. ) Is provided for the working device of the work vehicle, the detection result of only the second sensor (7) of the first sensor (6) and the second sensor (7) is changed to the descending side. Working device descending detection to detect that Means (15) are provided, and when the working device descending detection means (15) is in a detection state, it automatically operates to make the temporary dead zone (B) wider than the normal dead zone (A) the normal dead zone (A). In place of the dead zone changing means (16) for setting the position control means (9) to detect the detection results of the first sensor (6) and the second sensor (7) and the temporary dead zone (B). Based on this, the position control means (9) automatically operates when the cylinder raising operation is started, and the normal dead zone (A) is replaced with the temporary dead zone (B) and reset, and the second sensor ( Dead zone reset means (18) for causing the position control means (9) to perform a cylinder raising operation until the height (Z) detected by 7) falls within the normal dead zone (A).
A work vehicle lifting operation structure for a work vehicle that is provided with. 2. A first sensor (6) for detecting an operating direction and an operating stroke of a hydraulic cylinder (1) for vertically moving a working device (3) with respect to a traveling body, and an operating tool (5) for lifting and lowering the working device. And a second sensor (7) for detecting the height of the working device (3) with respect to the traveling machine body, and is proportional to the operation stroke of the operation tool (5) in accordance with the operation of the operation tool (5). Position control means (9) for automatically operating the hydraulic cylinder (1) based on the detection results of the first sensor (6) and the second sensor (7) while the working device (3) moves up and down the stroke. ) Is provided for the working device up-and-down operation structure of the work vehicle, wherein the detection result is changed only by the second sensor (7) of the first sensor (6) and the second sensor (7), Position control means (9) is oil An abnormal control detecting means (21) for detecting the start of the cylinder raising operation is provided, and when the abnormal control detecting means (21) is in the detection state, it automatically operates, and the detection result by the first sensor (6) Based on the positive control target height (X), the temporary control target height (Y) is higher than the normal control target height (X), and the normal dead zone (A) in the state based on the positive control target height (X) is entered and The temporary dead zone (D) based on the temporary control target height (Y) is set in place of the positive control target height (X) and the normal dead zone (A), and is set by the second sensor (7). A control form changing means (22) for causing the position control means (9) to perform a cylinder raising operation until the detection height (Z) enters the temporary dead zone (D) is provided, and detection by the second sensor (7) is performed. Before the height enters the temporary dead zone (D) The position control means (9) automatically operates when a cylinder stop operation is performed, and the positive control target height (X) and the normal dead zone (A) are provided to the position control means (9) as the temporary control target height. (Y) and a work device lifting / lowering operation structure for a work vehicle provided with a control mode resetting means (24) for resetting instead of the temporary dead zone (D).