JPH0250257B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for controlling the bucket angle of cargo handling and construction machinery.

FIG. 1 is a diagram showing the front part of a conventional loader hydraulic excavator. In the figure, 1 is the main body of a hydraulic excavator, 2 is a boom pivotally connected to the main body 1, 3 is an arm pivotally attached to the tip of the boom 2, 4 is a bucket pivotally attached to the tip of the arm 3, and 5 is the boom 2. A boom cylinder that moves up and down, 6 an arm cylinder that swings the arm 3, 7 a bucket cylinder that rotates the bucket 4, 8 to 10 hydraulic pumps, 11 to 1
3 is a directional switching valve that controls the boom cylinder 5, the arm cylinder 6, and the bucket cylinder 7.

In such a hydraulic excavator, when excavating by pushing out the bucket 4 horizontally (during horizontal extrusion operation), it is necessary to keep the bottom of the bucket 4 almost horizontal, and the boom 2 must be moved up and down to move the bucket 4. When moving upward (during boom raising operation), the opening of the bucket 4 must always face upwards to prevent the dirt inside the bucket 4 from spilling out. However, in order to perform such an operation, the directional control valves 11 to 13 must be operated at the same time, which is very troublesome and requires considerable skill. In addition, when moving the bucket 4 upward, the bucket 4 moves to a high place above the driver's head, so the driver cannot correctly detect the attitude of the bucket 4.
There is a risk that the dirt inside may fall onto the driver's cab, leading to an accident.

FIG. 2 is a diagram showing a conventional bucket belt angle control device for a hydraulic excavator. In this bucket belt angle control device, the head side of the bucket cylinder 7 is attached to the boom 2, and the piston rod of the bucket cylinder 7 is attached to the arm 3 and the bucket belt 4 via links 14 and 15.
Since the arm 3, link 14, and bucket cylinder 7 form an approximate parallelogram link, when the arm 3 swings upward, the bucket 4 rotates downward, and when the arm 3 swings downward, Bucket 4 rotates upward. Therefore, during the horizontal extrusion operation, the bottom surface of the bucket 4 can be kept substantially horizontal without operating the bucket cylinder 7.

FIG. 3 is a diagram showing another conventional bucket angle control device for a hydraulic excavator (Utility Model Application No. 53-48401).
In the figure, 16 is a level cylinder installed between the boom 2 and arm 3, 17 is an oil passage connecting the rod extrusion side chamber of the level cylinder 16 and the rod extrusion side chamber of the bucket cylinder 7, and 18 is the oil passage of the level cylinder 16. This is an oil passage that connects the rod retraction side chamber and the rod retraction side chamber of the bucket cylinder 7.

In this bucket angle control device, arm 3
When the arm 3 swings upward, the level cylinder 16 is extended, so the bucket cylinder 7 contracts, and the bucket 4 rotates downward, and when the arm 3 swings downward, the level cylinder 16 contracts. Therefore, the bucket cylinder 7 extends and the bucket cylinder 4
rotates upward. Therefore, during the horizontal extrusion operation, the bottom surface of the bucket 4 can be kept substantially horizontal without operating the bucket cylinder 7.

However, in the bucket belt angle control device shown in FIGS. 2 and 3, the bucket cylinder 7 must be operated in order to ensure that the opening of the bucket belt 4 always faces upward during the boom raising operation.

FIG. 4 is a diagram showing another conventional bucket angle control device for a hydraulic excavator (Japanese Unexamined Patent Publication No. 49-52404).
In the figure, 19 is a master cylinder installed between the main body 1 and the boom 2, 20 is an oil passage connecting the rod extrusion side chamber of the level cylinder 19 and the rod extrusion side chamber of the bucket cylinder 7, and 21 is the master cylinder of the master cylinder 19. This is an oil passage that connects the rod retraction side chamber and the rod retraction side chamber of the bucket cylinder 7.

In this bucket angle control device, the boom 2
When the boom 2 moves up and down, the master cylinder 19 is extended, so the bucket cylinder 7 contracts, and the bucket 4 rotates downward, and when the boom 2 is lowered,
Since the master cylinder 19 is contracted, the bucket cylinder 7 is extended and the bucket 4 is rotated upward. Therefore, during the boom raising operation, the opening of the bucket belt 4 can always be directed upward without operating the bucket cylinder 7.

However, in this bucket angle control device,
During the horizontal extrusion operation, the bucket cylinder 7 must be operated in order to keep the bottom surface of the bucket 4 substantially horizontal.

In addition, in the bucket belt angle control device shown in FIGS. 2 to 4, when the bucket belt 4 is retracted horizontally (during horizontal retraction operation), when the bucket belt 4 is moved downward by tilting the boom 2 (boom Since the angle between the bucket tip 4 and the vertical direction (bucket angle) is kept constant even during the lowering operation, there is no need for extra operations to return the bucket tip 4 to the digging position. I need.

FIG. 5 is a diagram showing another conventional bucket angle control device for a hydraulic excavator (Japanese Patent Application No. 83471/1983).
In the figure, 13a is an electromagnetic directional control valve provided between the hydraulic pump 10 and the bucket cylinder 7;
22 is an operation lever for operating the directional switching valve 13a, 23 is a calculation device, and the calculation device 23 is connected to the main body.
A boom relative displacement signal α ₁ , a boom/arm relative displacement signal α ₂ , and an arm/bucket relative displacement signal α ₃ are input, and a control signal I ₁ is output. 24 is a switch, and the switch 24 is for switching and connecting the directional control valve 13a, the operation lever 22, and the arithmetic device 23.

In this bucket belt angle control device, when the operating lever 22 and the directional switching valve 13a are connected by the switch 24, the directional switching valve 13a (bucket cylinder 7) is operated by the operating lever 22. In addition, the switch 24 causes the arithmetic unit 2 to
3 is connected, the arithmetic unit 23 calculates a control signal I ₁ for setting the bucket belt 4 to a predetermined bucket angle from the displacement signals α ₁ , α ₂ , α ₃ ,
Since the directional control valve 13a (bucket cylinder 7) is operated by this control signal _I1 , the bucket angle can be automatically maintained at an arbitrary predetermined value. Therefore, the bottom surface of the bucket 4 can be kept substantially horizontal during the horizontal extrusion operation, and the opening of the bucket 4 can always face upward during the boom raising operation. However, this bucket angle control device requires significant changes to the hydraulic circuit of a normal hydraulic excavator, which poses a practical problem.

This invention was made to solve the above-mentioned problems, and it is possible to automatically maintain the bucket angle at an arbitrary predetermined value, and without significantly changing the hydraulic circuit of ordinary cargo handling and construction machinery. The object of the present invention is to provide a bucket angle control device for cargo handling and construction machinery that can be applied.

In order to achieve this object, in the present invention, between the rod extrusion side oil passage and the rod retraction side oil passage of the bucket cylinder, the amount of oil flowing from the rod extrusion side oil passage to the rod retraction side oil passage is controlled externally. A flow rate control valve that can be controlled according to a signal from the rod is provided between the flow rate control valve and the rod retraction side oil passage, allowing flow from the upper rod extrusion side oil passage to the rod retraction side oil passage. A check valve is provided, and an oil path between the check valve and the flow control valve is connected to the tank, and posture signals of the main body, boom, arm, and bucket are input to control the flow control valve. A calculation device that outputs a control signal is provided.

FIG. 6 is a diagram showing a bucket angle control device for a hydraulic excavator according to the present invention. In the figure, 25,
26 is an oil passage on the rod extrusion side of the bucket cylinder 7;
Rod lead-in side oil passage, 27 is from oil passage 25 to oil passage 26
This is a flow control valve that can control the amount of oil flowing through the flow control valve 27 in accordance with an external signal, and when the signal sent to the flow control valve 27 is zero, the amount of oil flowing through the flow control valve 27 becomes zero. 28 is a check valve provided between the flow rate control valve 27 and the oil passage 26, and the check valve 28 is connected to the oil passage 25.
Flow from the oil passageway 26 to the oil passage 26 is allowed. 29 is check valve 28
An oil passage 31 connects the oil passage 30 between the flow rate control valve 27 and the tank, and 31 is a calculation device;
inputs the displacement signals α ₁ , α ₂ , α ₃ and controls the flow control valve 27 so that the bottom of the bucket 4 is almost horizontal during horizontal extrusion operations, and the opening of the bucket 4 is always upward during boom raising operations. A control signal I ₂ is output to control the flow rate control valve 27 so as to direct the flow rate control valve 27 to the direction shown in FIG. 32
is a switch provided between the arithmetic unit 31 and the flow rate control valve 27.

In this bucket belt angle control device, when the switch 32 is off, the amount of oil flowing through the flow rate control valve 27 is zero, so the bucket belt 4 can be manually operated by operating the direction switching valve 13. . Also, when the switch 32 is turned on,
When the arm 3 is swung upward to perform a horizontal extrusion operation, excavation resistance acts on the bucket 4, which generates pressure in the oil passage 25, and the flow rate control valve 27 opens in response to the control signal _I2 . The oil in the oil passage 25 flows through the flow control valve 27 in an amount corresponding to the control signal _I2 . Therefore, the bucket bag 4 rotates downward in response to the control signal _I2 , and the bottom surface of the bag bag 4 is kept substantially horizontal. At this time, oil is supplied to the oil passage 26 via the oil check valve 28 of the oil passage 25, and excess oil is removed from the oil passage 25.
9 and flows into the tank. Further, as shown in FIG. 7, when the boom 2 is raised and raised with the switch 32 turned on, pressure is applied to the oil passage 25 due to the weight of the bucket 4 and the earth and sand in the bucket 4. At the same time, the flow control valve 27 opens in response to the control signal I ₂ , so that the oil in the oil passage 25 flows through the flow control valve 27 in an amount corresponding to the control signal I ₂ . Therefore, the bucket bag 4 rotates downward in response to the control signal _I2 , and the opening of the bag bag 4 always faces upward.

FIG. 8 is a diagram showing another bucket angle control device for a hydraulic excavator according to the present invention. In the figure 3
3 is an arithmetic device, and the arithmetic device 33 receives displacement signals α ₁ ,
α ₂ and α ₃ are input, and a control signal I ₃ is output that controls the flow rate control valve 27 so that the opening of the bucket 4 always faces upward. 34 is a switch provided between the arithmetic device 33 and the flow rate control valve 27, and the switch 34 is turned on only when the directional control valve 13 is in the neutral position and the directional control valve 11 is in the boom-up position.

In this bucket belt angle control device, when the directional control valve 13 is operated, the switch 34 is turned off and the flow rate control valve 27 is closed, so that the bucket belt 4 can be manually operated. Further, when a horizontal extrusion operation is performed, the switch 34 is off,
Furthermore, since the bucket cylinder 7 and the like form an approximate parallelogram link, the bottom surface of the bucket 4 is kept substantially horizontal. Further, when the boom 2 is moved up and down to perform a boom raising operation, the switch 34 is turned on and the bucket belt 4 is rotated downward in response to the control signal _I3 , so that the opening of the bucket belt 4 always faces upward.

In the above embodiment, the bucket angle control device for a hydraulic excavator has been described, but the present invention can also be applied to bucket angle control for other cargo handling and construction machines such as a tractor shovel and a forklift with a loading attachment. . Further, in the above embodiment, relative displacement signals α ₁ , α ₂ , α ₃ are input as posture signals to the calculation devices 31 and 33, but the angles formed by the main body 1, boom 2, arm 3, and bucket 4 with the vertical direction You may input a signal according to the Furthermore, the relative displacement signals α ₁ , α ₂ , α ₃ may be signals corresponding to the angles formed by the respective members, or may be signals corresponding to the extension amounts of the boom cylinder 5, arm cylinder 6, and bucket cylinder 7.

As explained above, in the bucket belt angle control device for cargo handling and construction machinery according to the present invention, the bucket belt angle can be automatically maintained at an arbitrary predetermined value. Further, since it is only necessary to add a flow control valve and a check valve to a conventional hydraulic circuit, the conventional hydraulic circuit can be applied without major changes, and the cost is low. In particular, by connecting the rod extrusion side oil passage and the rod retraction side oil passage of the bucket cylinder via the check valve, there is no need for a long oil passage connecting the tank and the rod retraction side oil passage. As described above, the effects of this invention are remarkable.

[Brief explanation of drawings]

Figure 1 shows a conventional loader hydraulic excavator.
FIGS. 2 to 5 each show a conventional hydraulic excavator bucket angle control device, FIG. 6 shows a hydraulic excavator bucket angle control device according to the present invention, and FIG. FIG. 8 is a diagram illustrating another bucket belt angle control device for a hydraulic excavator according to the present invention. 1...Hydraulic excavator body, 2...Boom, 3...Arm, 4...Bucket, 5...Boom cylinder, 6...Arm cylinder, 7...Bucket cylinder, 25...Rod extrusion side oil path, 26...Rod retraction side oil path, 27
...Flow control valve, 28...Check valve, 31...Arithmetic device,
32...Switch, 33... Arithmetic device, 34... Switch.

Claims (1)

[Claims] 1. A boom that is pivotally attached to the main body and is moved up and down by a boom cylinder, an arm that is pivoted to the tip of the boom and is swung by an arm cylinder, and the tip of the arm. In a device for controlling a bucket belt angle of a cargo handling/construction machine having a bucket belt pivotally connected to a bucket belt and rotated by a bucket cylinder, the rod extrusion side oil passage and the rod retraction side oil passage of the bucket cylinder are connected to each other. A flow rate control valve capable of controlling the flow rate from the rod extrusion side oil path to the rod retraction side oil path in accordance with an external signal is provided between the flow rate control valve and the rod retraction side oil path. is provided with a check valve that allows flow from the rod extrusion side oil passage to the rod retraction side oil passage, and connects the oil passage between the check valve and the flow rate control valve to the tank; A bucket belt angle control device for cargo handling and construction machinery, characterized in that it is provided with an arithmetic device that inputs attitude signals of the main body, the boom, the arm, and the bucket truck and outputs a control signal for controlling the flow rate control valve. 2. The bucket angle control device for cargo handling and construction machinery as set forth in claim 1, further comprising a switch provided between the arithmetic unit and the flow rate control valve.