JP2001152481A - Front loader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a lift arm from moving up by mistake during scooping operation. SOLUTION: In the front loader provided with an attachment turning angle detecting means to detect the turning angle of an attachment, when a controller detects that the attachment has turned upward than a preset turning angle by a detecting means for a turning angle, the scooping operation is controlled to stop it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a front loader.

[0002]

2. Description of the Related Art In a conventional front loader 101, as shown in FIG. 7, a lift arm 104 is vertically rotatably arranged on a work machine side hitch 103 detachably mounted on a tractor 102 as the machine. At the tip of the lift arm 104, a bucket 105 as an attachment is vertically rotatably arranged, and hydraulic cylinders 106, 107 for operating the lift arm 104 and the bucket 105 and a hydraulic pump are connected via a hydraulic circuit. A controller is connected to a proportional control valve provided in the hydraulic circuit, and the lift arm 104 and the bucket 105 are operated by PWM-controlling the proportional control valve by the controller.

[0003]

However, in the above-mentioned conventional front loader, when the lift arm 104 is lowered, the weight of the lift arm 104 acts to lower the lift arm 104, and the lift arm 104 is raised and lowered. Supply of oil to the hydraulic cylinder 106
The inside of 106 sometimes became a vacuum.

When the lift arm 104 is lowered, a so-called squeeze operation is performed in which the tip of the bucket 105 is rotated upward while the hydraulic cylinder 106 is kept in a vacuum state. Of the lift arm 104 is rotated upward, and the mechanism for raising and lowering the lift arm 104 is formed of a parallel link.
A tensile force acts on the lift 104, and the lift arm 104 rises contrary to the operator's intention, and there is a possibility that the operation cannot be performed well.

In addition, if a so-called dumping operation is performed in which the tip of the bucket 105 is rotated downward after the squeeze operation, the lift arm 104 is suddenly lowered by an amount corresponding to the rise during the squeeze operation. Could not be performed safely.

[0006]

Therefore, according to the present invention, a lift arm is provided on the work machine side hitch so as to be vertically rotatable, and an attachment is provided at an end of the lift arm so as to be vertically rotatable. A hydraulic cylinder for operating the lift arm and the attachment and a hydraulic pump are connected via a hydraulic circuit, a controller is connected to a proportional control valve provided in the hydraulic circuit, and the proportional control valve is controlled by the controller. A front loader configured to actuate the arm and the attachment by means of an attachment. The front loader further includes attachment rotation angle detection means for detecting a rotation angle of the attachment, and the controller rotates the tip of the attachment upward. At the time of operation, the attachment is detected by the attachment rotation angle detection means. When it is detected that the pivoted upward to the rotation angle or more set was set to be controlled so as to stop the rake operation.

In addition, the controller is provided with a lift arm rotation angle detecting means for detecting a rotation angle of the lift arm, and the controller is adapted to perform a squeeze operation for rotating the tip of the attachment upward to perform the lifting operation. When it is detected by the rotation angle detecting means that the lift arm has risen, control is performed to stop the squeezing operation.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A front loader according to the present invention
A hydraulic cylinder and a hydraulic pump for operating the lift arm and the attachment by arranging a lift arm on the work machine side hitch so as to be able to rotate vertically and an attachment at the tip of the lift arm so as to be able to rotate vertically Are connected via a hydraulic circuit, a controller is connected to a proportional control valve provided in the hydraulic circuit, and the arm and the attachment are operated by controlling the proportional control valve by the controller.

In addition, there is provided an attachment rotation angle detecting means for detecting a rotation angle of the attachment,
When performing a squeeze operation in which the tip of the attachment is turned upward, the controller detects that the attachment has been turned upward by more than a preset rotation angle by the attachment rotation angle detection means. Is to control to stop the squeeze operation.

Therefore, the inside of the hydraulic cylinder for raising and lowering the lift arm does not become negative pressure, and it is possible to prevent a malfunction of the lift arm such that the lift arm rises against the intention of the operator. You can do it.

The controller further includes a lift arm rotation angle detecting means for detecting a rotation angle of the lift arm, and the controller includes a lift arm rotation means for performing a squeeze operation for rotating the tip of the attachment upward. When the lift angle is detected by the rotation angle detecting means, the inside of the hydraulic cylinder for raising and lowering the lift arm may be negative pressure by controlling to stop the squeeze operation. Therefore, it is possible to prevent a malfunction of the lift arm beforehand.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing a front loader 1 as a working machine according to the present invention. The front loader 1 is detachably mounted on a tractor 2 as the machine.

As shown in FIG. 1, the tractor 2 has a prime mover unit 4 disposed at the front of the body frame 3 and a driving operation unit 5 disposed at a position immediately behind the prime mover unit 4. A pair of left and right front wheels 6 and 6 and rear wheels 7 and 7 are provided at lower front and rear portions of the body frame 3, respectively.

The tractor 2 has a pair of right and left hitch stays 8, 8 attached to a middle part of the body frame 3, and has a hitch stay 9, 9 standing on each hitch stay 8, 8; , 9, a portal-shaped connecting frame 10 is straddling the front view.

The front loader 1 is, as shown in FIG.
Work equipment side hitch detachably mounted on the machine side hitches 9,9
At 11 and 11, the base ends of a pair of left and right lift arms 12, 12 as operating parts, which are substantially in the shape of a letter in a side view, are pivotably connected to each other vertically.
Attachment hitch at the end of the lift arms 12,12
13 is attached to the attachment hitch 13
A bucket 14, which is an attachment as an operating part, is detachably attached to the bucket. In the figure, 25 is a stand, and 83 is a connecting pin.

The front loader 1 has a hydraulic cylinder 15 for raising and lowering the lift arms 12, 12 between the lower part of the right work machine side hitch 11 and the lower part of the right lift arm 12. , A support 16 is pivotably mounted on the upper part of the right lift arm 12 in a vertically rotatable manner, and a connecting rod 17 is rotatable between a rear portion of the support 16 and an upper part of the right-side work hitch 11. At each pivot point 18, 19, 20, 21
Are positioned at the vertices of the parallelogram, and the hitch 11
The lift arm 12, the support 16 and the connecting rod 17 constitute a parallel link for lifting and lowering the lift arm 12.

Then, the lift arms 12, 12 are raised by extending the hydraulic cylinder 15 for raising and lowering.
On the other hand, the lift arms 12, 12 are lowered by shortening the lifting hydraulic cylinder 15.

Further, in the front loader 1, the base end of the connecting member 22 is attached to the distal end of the lift arm 12 so as to be vertically rotatable, and between the distal end of the connecting member 22 and the upper part of the support member 16. A hydraulic cylinder 23 for changing the attitude of the attachment by rotating the attachment is installed,
A connecting rod 24 is provided between the tip of the attachment 22 and the upper part of the attachment hitch 13. In the figure, 76, 78, 79 are pivot points,
84 is a connecting pin.

The distal end of the attachment is rotated downward by extending the hydraulic cylinder 23 for changing the attitude. At this time, when the bucket 14 is mounted as an attachment, a dump operation is performed in which the tip of the bucket 14 is lowered downward. On the other hand, by shortening the posture changing hydraulic cylinder 23, the distal end of the attachment is rotated upward. At this time, when the bucket 14 is mounted as an attachment, a squeeze operation is performed in which the tip of the bucket 14 is swung upward.

The front loader 1 includes a lift arm rotation angle detecting means 71 for detecting the rotation angle of the lift arm 12 and an attachment rotation angle detecting means 72 for detecting the rotation angle of the attachment. Are provided.

The lift arm rotation angle detecting means 71 is provided at the pivot 21 of the support 16 and the connecting rod 17 at a potentiometer 73.
, And the detection arm 74 of the potentiometer 73 is slidably held by a pair of upper and lower pins 75, 75 erected on the connecting rod 17.
36, the rotation angle of the lift arm 12 is detected by the rotation angle of the detection arm 74 of the potentiometer 73.

Attachment rotation angle detecting means 72 includes a potentiometer 80 attached to a pivot 78 between the attachment hitch 13 and the connecting rod 24, and a pair of upper and lower detecting arms 81 of the potentiometer 80 erected on the connecting rod 24. Pin 8
2 and 82 are slidably held, and the potentiometer 80 is connected to the controller 36 and the potentiometer 80
The rotation angle of the attachment is detected by the rotation angle of the detection arm 81.

FIG. 5 shows the hydraulic cylinders 15 and 23 for operating the operating parts of the lift arm 12 and the attachment.
FIG. 3 is a diagram showing a hydraulic circuit 27 interposed between the hydraulic pump 27 and the hydraulic circuit 27. The hydraulic circuit 27 is provided between the hydraulic cylinder 15 for raising and lowering the lift arm 12 and the hydraulic pump 26. In order to interpose a pair of proportional control valves 30 and 31 at both ends of a spool 29 of the flow path switching valve 28, and to change the attitude of the attachment, A flow path switching valve 32 for changing the attitude of the attachment is provided between the hydraulic cylinder 23 and the hydraulic pump 26, and a pair of proportional control valves 34 and 35 are provided at both ends of a spool 33 of the path switching valve 32. And the proportional control valves 30, 31, 34, 35 are connected to the controller 36. In the figure, 54 is a battery, 55 is a proportional control valve 30, 31, 34, 3
5 is a drive voltage detecting means for detecting the drive voltage, 56 is an interface for PWM output, and 57 is a CPU.

Then, the proportional control valves 30, 31, 34 and 35 are PWM-controlled by the controller 36 to operate the respective operating portions (see FIG. 6. In FIG. 6, reference numeral 85 denotes the engine). Engine speed detection means for detecting the speed, and 86 is a warning means for generating a warning sound.)

The controller 36 is connected to an EEPROM containing control data.

An operation unit 37 is connected to the controller 36. The operation unit 37 is disposed at a position on the right side of the operation operation unit 5.

That is, as shown in FIGS. 2 to 4, the base ends of a pair of front and rear supports 38, 39 are attached to the right side of the driving operation unit 5 so as to be able to flip up upward. 38,3
9 and a body casing 41 is attached to the front support body 38, and the body casing 41
A joystick-type operation lever 42 is erected on 41, and a float button 43, a horizontal button 44,
While the third circuit switching button 45 and the one-touch button 46 are provided respectively, the loader power switch is
47, a horizontal angle setting dial 48, and an auto button 49 are provided.

At the base end of the operation lever 42, an operation lever 42
A lever sensor 50 for detecting the direction and the swing angle at which the swing operation is performed is attached, and the lever sensor 50 and various operation members 43, 44, 45, 46, 47, 48, and 49 are connected to the controller 36. I have.

At the base end of the operation lever 42, there is provided a display panel 51 showing the operation of the lift arm 12 and the attachment in accordance with the swing operation of the operation lever 42. The operability is improved by making it easy to see in which direction the operation lever 42 should be rocked.

That is, the operation lever 42 is moved rearward (in FIG. 4,
When the swing operation is performed in the direction indicated by the arrow 52), the controller 36
Performs PWM control on the proportional control valve 31, and the proportional control valve 31
By switching the spool 29 of the flow path switching valve 28 to the ascending flow path 53 with the pilot pressure according to the duty ratio of the input pulse, and extending the hydraulic cylinder 15 for raising and lowering with the oil amount according to the pilot pressure, the lift arm 12
Rise at a speed corresponding to the pilot pressure.

At this time, the controller 36 operates the operating lever
A pulse is input to a coil that operates the spool of the proportional control valve 31 in accordance with the swing angle of 42, and the duty ratio of the pulse is increased as the swing angle of the operation lever 42 is increased, and the The hydraulic cylinder 15 is extended at a high speed, and the lift arm 12 is raised at a high speed.

Further, the operation lever 42 is moved forward (in FIG.
When the swing operation is performed in the direction indicated by 58), the controller 36
The proportional control valve 30 is subjected to PWM control. In the proportional control valve 30, the spool 29 of the flow path switching valve 28 is switched to the descending flow path 59 at a pilot pressure corresponding to the duty ratio of the input pulse, and the oil amount corresponding to the pilot pressure is controlled. , The lift arm 12 is lowered at a speed corresponding to the pilot pressure.

At this time, when the float button 43 is pressed, the controller 36 switches the spool 29 of the flow path switching valve 28 to the float flow path 60, and connects the hydraulic cylinder 15 for raising and lowering to the hydraulic tank. Then, the lift arm 12 is lowered by its own weight.

When the operation lever 42 is swung leftward (in the direction indicated by the arrow 61 in FIG. 4), the controller 36
Performs PWM control on the proportional control valve 34, and the proportional control valve 34
By switching the spool 33 of the flow path switching valve 32 to the squeeze flow path 62 with the pilot pressure according to the duty ratio of the input pulse, and shortening the hydraulic cylinder 23 for changing the attitude with the oil amount according to the pilot pressure,
The tip of 14 rotates upward at a speed corresponding to the pilot pressure, and the bucket 14 takes a rearwardly inclined posture to perform the squeeze operation.

At this time, in this embodiment, the controller 36
When the attachment rotation angle detecting means 72 detects that the attachment has rotated upward by a predetermined rotation angle (for example, 30 degrees) or more, control is performed to stop the squeezing operation. I have.

As a result, the inside of the hydraulic cylinder 15 for raising and lowering the lift arm 12 does not become negative pressure, and the erroneous operation of the lift arm 12 such that the lift arm 12 rises against the operator's will is prevented. Can be prevented.

When the controller 36 performs the squeeze operation of rotating the tip of the attachment upward, the controller 36 also detects that the lift arm 12 has been lifted by the lift arm rotation angle detecting means 71. It controls to stop the squeeze operation.

This also prevents the inside of the hydraulic cylinder for raising and lowering the lift arm 12 from becoming negative pressure, thereby preventing erroneous operation of the lift arm 12 before it occurs.

When the operation lever 42 is swung rightward (in the direction indicated by arrow 63 in FIG. 4), the controller 36
However, the PWM control of the proportional control valve 35 is performed.
By switching the spool 33 of the flow path switching valve 32 to the dump flow path 64 with the pilot pressure according to the duty ratio of the input pulse, and extending the hydraulic cylinder 23 for attitude change with the oil amount according to the pilot pressure,
The tip of 14 rotates downward at a speed corresponding to the pilot pressure, and the bucket 14 takes a forward leaning posture to perform a dump operation.

When the operation lever 42 is set upright,
The controller 36 sets the proportional control valve 30 or the proportional control valve 31 to P
Performs WM control and sets the spool 29 of the flow path switching valve 28 to a neutral flow path.
65, shut off the flow path between the hydraulic cylinder 15 for raising and lowering and the hydraulic tank, and perform PWM control on the proportional control valve 34 or the proportional control valve 35, and connect the spool 33 of the flow path switching valve 32 to the neutral flow path 66. The flow path between the hydraulic cylinder 23 for switching and posture change and the hydraulic tank is shut off, and the posture of the lift arm 12 and the bucket 14 is maintained.

When the operation lever 42 is swung in an oblique direction, the lift arm 12 and the attachment operate in a combined manner. That is, the operation lever 42 is moved to the left rear side (FIG. 4).
When the swing operation is performed in the middle and in the direction indicated by the arrow 67), the attachment is squeezed while the lift arm 12 is raised, and when the operation lever 42 is operated to swing to the right rear (in the direction indicated by the arrow 68 in FIG. 4), When the lift arm 12 is lifted while the attachment is dumping, and the operation lever 42 is swung forward and left (in the direction indicated by an arrow 69 in FIG. 4), the attachment is squeezed while the lift arm 12 is lowered.
Move the operation lever 42 to the front right (in the direction indicated by the arrow 70 in FIG. 4).
When the swing operation is performed, the attachment is dumped while the lift arm 12 is lowered.

[0043]

The present invention is embodied in the form described above and has the following effects.

(1) According to the present invention, there is provided an attachment rotation angle detecting means for detecting the rotation angle of the attachment, and the controller performs the squeezing operation for rotating the tip of the attachment upward. If the attachment rotation angle detecting means detects that the attachment has rotated upward by more than a preset rotation angle, the lift arm is moved upward and downward because the squeezing operation is controlled to stop. The inside of the hydraulic cylinder for performing the operation does not become negative pressure, and it is possible to prevent a malfunction of the lift arm such that the lift arm rises against the intention of the operator.

(2) In the present invention, a lift arm rotation angle detecting means for detecting the rotation angle of the lift arm is provided, and the controller performs a squeeze operation for turning the tip of the attachment upward. In this case, when the lift arm rotation angle detecting means detects that the lift arm has been lifted, the hydraulic cylinder for controlling the lift arm to move up and down is controlled by stopping the squeeze operation. Does not become negative pressure, and erroneous operation of the lift arm can be prevented.

[Brief description of the drawings]

FIG. 1 is a side view showing a front loader according to the present invention.

FIG. 2 is a plan view showing an operation unit.

FIG. 3 is a side view of the same.

FIG. 4 is a plan view showing a display panel.

FIG. 5 is an explanatory diagram showing a hydraulic circuit.

FIG. 6 is a block diagram showing a control unit of the front loader.

FIG. 7 is an explanatory view showing the operation of a conventional front loader.

[Explanation of symbols]

 1 Front loader 2 Tractor 11 Work machine side hitch 12 Lift arm 13 Attachment hitch 14 Bucket 15 Hydraulic cylinder 16 Support 17 Connecting rod 22 Connecting body 23 Hydraulic cylinder 24 Connecting rod 26 Hydraulic pump 27 Hydraulic circuit 28,32 Flow switching valve 30 , 31,34,35 Proportional control valve 36 Controller 42 Operation lever 71 Lift arm rotation angle detection means 72 Attachment rotation angle detection means

Claims (2)

[Claims] A lift arm is provided on a work machine side hitch so as to be vertically rotatable, and an attachment is provided at an end of the lift arm so as to be vertically rotatable to operate the lift arm and the attachment. A structure in which a hydraulic cylinder and a hydraulic pump are connected via a hydraulic circuit, a controller is connected to a proportional control valve provided in the hydraulic circuit, and the arm and the attachment are operated by controlling the proportional control valve by the controller. The front loader further comprises an attachment rotation angle detecting means for detecting a rotation angle of the attachment, wherein the controller is configured to rotate the attachment rotation angle when performing a squeeze operation of rotating the tip of the attachment upward. Attachment is turned upward by more than the preset rotation angle by detecting means When it is detected that the rotation, the front loader and controlling so as to stop the rake operation. 2. A lift arm rotation angle detecting means for detecting a rotation angle of the lift arm, wherein the controller performs a squeeze operation for rotating the tip of the attachment upward to perform the lifting operation. A front loader, which controls to stop the squeezing operation when the lift angle detecting means detects that the lift arm has risen.