JP2000054423A - Front loader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve control reliability and to simplify handling operation by impeding the malfunction of a bucket cylinder in advance. SOLUTION: A front loader is provided with a lift arm 14 elevated by an arm cylinder 25, and a bucket 22 changed in the attitude by a bucket cylinder 31 is fitted to the tip of the lift arm 14. The output abnormality of a bucket sensor 41 for detecting the support angle of the bucket 22 is detected on the basis of the elevating action of the lift arm 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front loader in which a tractor is provided with a lift arm, and a bucket or a roll club is attached to the lift arm to perform earthworks or cargo handling work.

[0002]

Conventionally, an arm cylinder for raising and lowering a lift arm and a bucket cylinder for operating a bucket are provided, and a bucket is scooped (tilted) while detecting the lift arm height and the bucket posture with sensors.
There is a technology for operating or discharging (dumping). However, in the prior art, an error is determined based on an output (sensor voltage) outside the operating range of the bucket sensor and an abnormality of the bucket sensor is detected. Even if it breaks down due to earth and sand, it cannot detect the abnormality of the bucket sensor, causing malfunctions of the bucket cylinder and bucket. This can easily improve the reliability of bucket control and simplify the handling operation. There are problems such as not. Further, there is a problem that the dump speed switching operation cannot be easily performed by switching the dump speed of the bucket by the valve unit.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention detects a bucket support angle in a front loader in which a lift arm which is raised and lowered by an arm cylinder is provided and a bucket whose posture is changed by a bucket cylinder is attached to the tip of the lift arm. The output of the bucket sensor is determined to be abnormal when the output of the bucket sensor does not change due to the lifting and lowering of the lift arm. Can detect the failure of the bucket sensor when it breaks down while it is kept in the operating range, prevent the malfunction of the bucket cylinder and bucket, and improve the reliability of the bucket control and simplify the handling operation. It is possible to achieve.

Further, a bucket sensor is provided in a rotating mechanism of a bucket attached to a lift arm via a parallel link member, so that a bucket posture detecting structure can be simplified and a manufacturing cost can be easily reduced.

[0005] Further, an abnormality of the bucket sensor is detected based on an output change amount of an arm sensor for detecting lifting and lowering of the lift arm and an output change amount of the bucket sensor. Can be properly determined, and the arm sensor used for the automatic lifting / lowering control of the lift arm can also be used for the abnormality check of the bucket sensor, so that the automatic control structure of the lift arm and the bucket can be simplified and the control function can be easily improved. Things.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view of the entirety, in which an engine (5) and a hood (6) are mounted on a front upper portion of a chassis frame (4) of a tractor (3) on which front and rear wheels (1) and (2) are mounted. Chassis frame (5)
A steering handle (7) and a driver's seat (8) are mounted on the upper rear part. Further, a loader main frame (9) is fixed to the front side surface of the chassis frame (5), a base frame (10) is fixed to the rear part of the frame (9), and shafts (11) and (12) are fixed to the base frame (10). ), The sub-frame (13) is detachably fixed, and the base ends of the lift arm (14) and the rod (15) are connected to the sub-frame (13) via shafts (16) and (17). And the hitch (1) at the tip of the lift arm (14) via the shaft (18).
9) and the hitch (19) is connected to the shaft (20) (2).
The bucket (22) is detachably fixed via 1).

Further, an arm cylinder (25) is connected to the lower intermediate portion of the sub-frame (13) and the lift arm (14) via shafts (23) and (24), thereby forming a lift arm (1).
4) A receiving plate (26) is provided on the middle upper side, a rod (15) is connected to the receiving plate (26), and the rod (15) is attached substantially parallel to the lift arm (14). Hitch (19) and flexible link (27)
(28) Both ends are connected, and the link (27) (28)
The dump cylinder (31) is connected between the intermediate portion and the receiving plate (26) via shafts (29) and (30).
4) and raising and lowering the bucket (22), and performing a dumping (discharge) operation of lowering the bucket (22) by extending the dump cylinder (31), and reducing the size of the dump cylinder (31). (Scooping) operation is performed so that the soil is turned upward, the soil or compost is scooped by the tilting operation, and the soil or compost is dropped by the dumping operation.

Further, as shown in FIGS. 2 and 3, a receiving plate (26) is connected to the lift arm (14) via a shaft (32), and the receiving plate (26) is connected to the receiving plate (26) via a shaft (33). The rod (15) is connected, a parallel link mechanism is formed by the lift arm (14) and the rod (15), and the sensor bracket (34) is fixed to a shaft (33) to be fixed to the receiving plate (26). The potentiometer type arm sensor (35) is fixed to the bracket (34), the tip of the rotating body (36) of the arm sensor (35) is sandwiched between the cylindrical projections (37) and (37) of the rod (15), and the lift arm ( The rod (15) is rotated about the axis (33) by the elevation of the lift arm (14), the rotating body (36) is rotated by the projection (37), and the amount of elevation of the lift arm (14) is detected by the sensor (3).
It is configured to detect by the voltage change of 5).

Further, as shown in FIGS. 4 and 5, a shaft (30) is fixed to the link (27), the link (28) and the receiving cylinder (38) are rotatably mounted on the shaft (30), Insert the tip of the piston (39) of the cylinder (31) into the receiving cylinder (3
8), a sensor bracket (40) is fixed to the shaft (30), and a potentiometer type bucket sensor (41) is fixed to the bracket (40).
Further, a level frame (42) is fixed to the receiving cylinder (38), and a level gauge (43) for visually confirming the posture of the bucket (22) by an operator is connected to the frame (42). Sensor cover (44)
Is fixed, the tip of the rotating body (46) of the sensor (41) is brought into contact with the cylindrical protrusion (45) of the cover (44), and the link (2) for dumping and tilting the bucket (22) is operated.
7) The cover (44) is rotated around the axis (30) by the bending of (28), and the rotating body (4) is rotated by the projection (45).
6) is rotated so that the attitude (dump and tilt amounts) of the bucket (22) is detected by a voltage change of the sensor (41).

Further, as shown in FIG. 6, an engine (5)
Loader hydraulic pump (47), arm valve (48) for raising / lowering and floating operation of arm cylinder (25), and dump cylinder (3).
A bucket valve (49) for tilting, dumping, and speed-up dumping of 1) is provided, and a hydraulic pump (47) is connected to each cylinder (25) (3) via each valve (48) (49).
1) is hydraulically connected, and the valves (48) and (49) are switched to operate the cylinders (25) and (31). Also,
Lift valve (51) having lift solenoid (50)
And a descending valve (5) having a descending solenoid (52).
3) is provided, and the valves (51) and (53) are switched by the solenoids (50) and (52).
The arm valve (48) is switched by (53) and the arm cylinder (25) is operated to lift the arm (14).
And a tilt valve (55) having a tilt solenoid (54), and a dump solenoid (56)
A dump valve (57) is provided, and each valve (55) (57) is switched by each solenoid (54) (56), and a bucket valve (49) is switched by each valve (55) (57). 31) is operated to change the attitude of the bucket (22).

Further, as shown in FIGS. 1 and 7, a joystick (58) is erected on the right side of the driver's seat (8) so as to be tiltable back and forth and right and left, and an arm cylinder (2) is provided.
5) a float switch (59) for performing a floating operation of releasing the hydraulic pressure to lower the lift arm (14) by its own weight, and a lift arm (1) to a target value to be initially set.
4) a one-touch switch (60) for automatically performing the operation of elevating and lowering, a horizontal switch (61) for automatically performing the operation of elevating and lowering while supporting the bucket (22) substantially horizontally to the ground, and a bucket cylinder. A mode changeover switch (62) for dumping (31) at high speed is provided on the gripping head (37) of the joystick (58), and a worker sitting in the driver's seat (8) can handle the steering wheel (7) with his left hand. While holding the joystick (58) with the right hand, the switches (59) to (62) are operated to carry out earthwork and other cargo handling operations, and the joystick (5) is operated.
8) The arm potentiometer (6
3), a bucket potentiometer (64) interlocked with the left / right tilting of the joystick (58), the switches (59) to (62), and the solenoids (50).
(52) The (54) and (56) are connected to a loader controller (65) formed by a microcomputer, and the operation of the bucket (22) or the operation of the lift arm (14) is performed by tilting the joystick (58) left or right or back and forth. , The arm valve (48) or the bucket valve (49) is driven, and the lift arm (14) is raised or lowered, and the bucket (22) is tilted or dumped.

Further, the arm sensor (35) for detecting the position of the lift arm (14) moved up and down by the arm cylinder (25) and the bucket sensor (4) for detecting the operation position of the bucket (22) by the bucket cylinder (31).
1) is connected to the loader controller (65), and the lift arm (1) is operated by operating the joystick (58).
4) After moving up and down to a desired position, the one-touch switch (60) is turned on and the joystick (58) is neutralized for a certain period of time, so that the lift arm (14) is input by the arm sensor (35). The position is stored as a target value, and a drive command is issued to the target value by turning on the one-touch switch (60) and tilting the joystick (58), and the lift arm (14) is automatically controlled by the arm cylinder (25). Is automatically raised and lowered to the target value.

A speed-up mode display lamp (66) for displaying the speed-up dump switching of the mode change-over switch (62).
And an error display lamp (67) for indicating a failure of the bucket sensor (41) by the loader controller (65).
As shown in the flowchart of FIG. 8, when the joystick (58) is raised or lowered and the output of the arm sensor (35) changes by a certain amount or more, the output of the bucket sensor (41) becomes constant. If there is no change, the output error of the bucket sensor (41) is detected, the error display lamp (67) is turned on to notify the failure of the bucket sensor (41), and the horizontal switch (6) is turned on.
The automatic control of 1) is configured to be stopped.

As is apparent from the above description, a lift arm (14) for raising and lowering by an arm cylinder (25) is provided, and a bucket (22) for changing the attitude by a bucket cylinder (31) is attached to the tip of the lift arm (14). In the loader, the output abnormality of the bucket sensor (41) for detecting the support angle of the bucket (22) is detected based on the lifting / lowering operation of the lift arm (14).
When the output of the bucket sensor (41) does not change, it is determined that the bucket sensor (41) is abnormal. When the bucket sensor (41) fails while the output of the bucket sensor (41) is kept within the operating range and when the bucket sensor (41) fails outside the operating range, the bucket sensor (41) 41), the bucket cylinder (31) and the bucket (2) are detected.
The malfunction of 2) is prevented beforehand, and the reliability of the control of the bucket (22) is improved and the handling operation is simplified. In addition, a bucket sensor (41) is provided on the bending links (27) and (28) which are rotation mechanisms of the bucket (22) attached to the lift arm (14) via the rod (15) which is a parallel link member. (22) A bucket sensor is provided based on the output change amount of an arm sensor (35) for detecting the elevation of the lift arm (14) and the output change amount of the bucket sensor (41), while simplifying the posture detection structure and reducing the manufacturing cost. An abnormality of (41) is detected, and the appropriateness of the operation of the bucket sensor (41) at the time of lifting / lowering of the lift arm (14) is appropriately determined. The arm sensor (35) used for automatic lifting / lowering control of the lift arm (14) is used as a bucket. Simplifies the automatic control structure of the lift arm (14) and the bucket (22) and improves the control function, also used for checking the abnormality of the sensor (41). It is configured so as attained the etc..

Further, an electronic governor (not shown) having a rotation sensor (68) for detecting the rotation speed of the engine (5) and a fuel solenoid (69) for adjusting the fuel supply amount of the engine (5) is automatically controlled. The electronic governor controller (70) is connected to the loader controller (65), and as shown in the flowchart of FIG. 9, the joystick ( 58)
When the joystick (58) is moved to the upside, the control of the electronic governor controller (70) for increasing the rotation speed of the engine (5) to increase the ascending speed of the lift arm (14) is performed, and the joystick (58) is moved to the downside. When the arm valve (4) is operated to the maximum position by the descending valve (53).
8) is switched to the maximum descent speed position, and the lift arm (14) is lowered at high speed regardless of the engine (5) rotation speed.
When the switch (62) is not in the speed-up dump switching mode, the arm valve (48) is throttle-adjusted to the descending side by the descending valve (53) so that the descending throttle amount is proportional to the engine (5) rotation speed. The lift arm (14) is lowered at a speed change proportional to the rotation speed of the engine (5), and the rotation of the engine (5) is adjusted to change the descent speed of the lift arm (14) to a desired speed.

As shown in the flowchart of FIG. 10, when the joystick (58) is maximally operated to the scooping (tilt) side by setting the speed increasing mode by the speed increasing dump switching operation of the mode change switch (62). The electronic governor controller (70) for increasing the scooping speed of the bucket (22) by increasing the number of revolutions of the engine (5) was controlled to perform high-load work, and the joystick (58) was operated to the maximum on the dump side. At this time, the switching control of the bucket valve (49) for driving the spool to the speed-increasing dump position is performed by the dump valve (57), and the bucket (22) is dumped at high speed, while the operation of the joystick (58) other than the maximum dump operation is performed. The bucket bar that drives the spool to the throttle position corresponding to the tilt angle of the joystick (58) Bed (49) to perform control. Further, when the mode other than the speed increasing mode is selected, the joystick (5
The bucket valve (49) that drives the spool to the maximum throttle position is performed by the dump maximum operation of 8), and the joystick (5) other than the dump maximum operation is controlled.
8) The operation controls the bucket valve (49) for driving the spool to the aperture position corresponding to the tilt angle of the joystick (58). As described above, while the operator in the driver's seat (8) continues the work, the mode change switch (6)
2) In addition to the dump speed-up operation, the speed of the engine (5) is increased during each operation of the lift arm (14) ascending and the bucket (22) scooping to prevent engine (5) output shortage and lift. Each operation of lowering the arm (14) and dumping the bucket (22) is performed at high speed, thereby improving work efficiency.

[0017]

As is apparent from the above embodiment, the present invention provides a lift arm (14) which is raised and lowered by an arm cylinder (25), and a bucket (22) whose posture is changed by a bucket cylinder (31). (14) In the front loader attached to the tip, a bucket sensor (4) for detecting the support angle of the bucket (22)
The output abnormality of (1) is detected based on the lifting / lowering operation of the lift arm (14).
When the output of the bucket sensor (41) does not change due to the lifting and lowering of 4), it is determined that the bucket sensor (41) is abnormal. Therefore, when the output of the bucket sensor (41) fails while maintaining the output in the operating range. Abnormality of the bucket sensor (41) can be detected in the bucket cylinder (31).
In addition, the malfunction of the bucket (22) can be prevented beforehand, and the reliability of the control of the bucket (22) can be improved, and the handling operation can be easily simplified.

Further, a bucket sensor (41) is provided in a rotating mechanism (27) (28) of a bucket (22) attached to a lift arm (14) via a parallel link member (15). ) The posture detection structure can be simplified and the manufacturing cost can be easily reduced.

Further, the bucket sensor (4) is determined by the output change of the arm sensor (35) for detecting the elevation of the lift arm (14) and the output change of the bucket sensor (41).
The arm sensor is configured to detect the abnormality of 1), and can appropriately determine whether the operation of the bucket sensor (41) at the time of lifting and lowering of the lift arm (14) is appropriate, and an arm sensor used for automatic lifting control of the lift arm (14). (35) can also be used for checking the abnormality of the bucket sensor (41), and the automatic control structure of the lift arm (14) and the bucket (22) can be simplified and the control function can be easily improved.

[Brief description of the drawings]

FIG. 1 is an overall side view.

FIG. 2 is a side view of an arm sensor unit.

FIG. 3 is a plan view of the same.

FIG. 4 is a side view of a bucket sensor unit.

FIG. 5 is a plan view of the same.

FIG. 6 is a hydraulic circuit diagram.

FIG. 7 is a control circuit diagram.

FIG. 8 is an error detection control flowchart.

FIG. 9 is a flowchart of a lift control.

FIG. 10 is a flowchart of a dump control.

[Explanation of symbols]

 (14) Lift arm (15) Rod (parallel link member) (22) Bucket (25) Arm cylinder (27) (28) Bend link (rotation mechanism) (31) Bucket cylinder (35) Arm sensor (41) Bucket sensor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2D003 AA01 AB03 AB04 AC04 BA02 BA06 BA07 BA08 BB10 CA03 DA04 DB03 DB04 DB05 EA02 EA05 FA02 2D015 GB01 HA03

Claims (3)

[Claims] 1. A front arm which is provided with a lift arm which is moved up and down by an arm cylinder, and in which a bucket whose posture is changed by a bucket cylinder is attached to a tip of the lift arm, an output abnormality of a bucket sensor for detecting a supporting angle of the bucket is lifted and lowered. A front loader, characterized in that the front loader is configured to perform detection based on the front loader. 2. The front loader according to claim 1, wherein a bucket sensor is provided in a rotating mechanism of a bucket attached to the lift arm via a parallel link member. 3. The front loader according to claim 1, wherein an abnormality of the bucket sensor is detected based on an output change amount of an arm sensor for detecting lifting and lowering of the lift arm and an output change amount of the bucket sensor. .