JPS60133127A - Method of controlling bucket angle of loading shovel - Google Patents

Abstract

PURPOSE:To prevent dropping of earth during movement, by a method wherein, when either a boom or an arm is controlled and height from the reference surface of a bucket exceeds a given value a bucket angular speed signal, determined from a boom, an arm, and a bucket angle, is outputted. CONSTITUTION:The angle alpha of a boom 2, the angle beta of an arm 3 and the angle gamma of a bucket are respectively detected, and a deviation DELTAgamma between a bucket absolute angle theta=alpha+beta+gamma and a desired absolute angle theta0 is determined. Further, a difference (bucket angular speed) between the differentiation value of the addition value of the boom angle alpha and the arm angle beta and the deviation DELTAgamma is determined. Meanwhile, from the boom angle alpha, the arm angle beta, and the bucket angle gamma, a height (h) from a reference value G.L of a bucket 4 is determined. Only when the height (h) exceeds a set height and at least either of boom and control levers 13 and 14 is controlled, an instruction signal T is outputted from a control instruction device 33 to input a bucket angular speed to a bucket controller 28.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a packet angle control method for preventing earth and sand loaded on packets of a loading hydraulic excavator from falling.

In order to prevent the earth and sand loaded in the packet from falling when the boom of a loading hydraulic excavator is raised, it is necessary to keep the angle of the packet from the horizontal plane, that is, the absolute packet angle Y, constant during the operation of the boom or arm. Such operations require advanced techniques and a great deal of effort. In order to solve this problem, it is sufficient to automatically make the absolute packet angle constant without any packet manipulation, and methods for this include a link method, a hydraulic method, and an electrical method. Several methods have been proposed.

In these proposals, as the value of the packet absolute angle to be kept constant, there are some that always take a constant value given in advance, and others that take the packet absolute angle as a constant value at the time when operation of the boom or arm is started.

However, in the former case, the absolute packet angle will be a constant value regardless of the operator's will, so the absolute packet angle will be changed depending on the sediment loading status of the packet. ! There are drawbacks such as the inability to perform raking and excavation by performing packet operations while the boom is being raised.
Unfavorable in terms of operability.

In the latter case, the disadvantage of the former can be compensated for by adding packet manipulation to correct the packet absolute angle, but the excavation ends when the packet is near or below the ground surface. When a packet is generated, the packet angle cannot be adjusted sufficiently due to link constraints. Therefore, if the absolute packet angle is maintained, the packet will tilt too far forward. Further, even if only the boom or arm is operated during excavation, packet angle control is performed, which deteriorates the operability for excavation.

The present invention was made in view of the drawbacks of the above-mentioned prior art, and
It is an object of the present invention to perform packet angle control 4 according to an operator's will and when the height of a reference plane edge of a packet becomes a predetermined value or more.

In order to achieve this objective, the present invention provides a condition in which the height of the bucket (bucket) from the reference plane is greater than or equal to a set value, at least one of the boom operation lever and the arm operation lever is operated, and the packet operation lever 4- is not operated. When this holds true, the operation of the packet cylinder is controlled using the absolute angle signal of the next packet as a target value.

Embodiment V of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a diagram showing the front part of the ts rotary ink hydraulic excavator. In the figure, l is the main body of the hydraulic excavator, 2 is a boom pivoted to the main body l, 3 is an arm pivoted to the tip i of the boom 2, 4 is a packet pivoted to the tip of the arm 3, and 5 is the boom 2 6 is an arm cylinder that swings the arm 3, 7 is a packet cylinder that rotates the packet 4, 8 detects the boom 20 angle relative to the main body l, that is, the boom angle, and outputs a boom angle signal α. An angle meter 9 detects the angle of the arm 30 relative to the boom 2, that is, the arm angle, and outputs an arm angle signal β, V; an angle meter 10 detects the angle of the packet 4 relative to the arm 3, that is, the packet angle, and outputs the packet angle signal γ It is an angle meter that outputs .

FIG. 2 is a diagram showing a control device for implementing the method for controlling the packet angle of a loading shovel according to the present invention. In the figure, 11 is a hydraulic pump, 12 is an electromagnetic control valve provided between the hydraulic pump 11 and the packet cylinder 7, 13,
14 and 15 are the boom operation lever, arm operation lever, and packet operation lever, respectively, and 16 are the angle signals α, β, and γ.
17 is the adder 1 when the switch 18 is turned on.
19 is an output signal θ of the storage device 17; and the output signal θ of the adder 16, that is, the angular deviation signal Δγ. 20 is the output signal of the adder/subtractor 19! 21 is a coefficient unit 20 that multiplies the coefficient and outputs Δr to the signal.
22 is a manual operation device that outputs a manual operation signal according to the amount of operation of the packet operation lever 15, and 23 is a sum of the boom angle signal α and the arm angle signal β. an adder; 24 is a differentiator that differentiates the output signal α+β of the adder 23; 25 is an adder that calculates the difference between Δr and the output signal of the differentiator 24 &ten3-7F in the output signal of the coefficient multiplier 20; 26 is an adder that sums the output signal of the adder/subtractor z5 and the output signal of the manual operating device 22; 27 is a switch provided between the adder/subtractor 25 and the adder 26; Solenoid control valve 12V to increase and compensate the speed of the packet cylinder 7
The amplifiers to be controlled, 29, 30, and 31 are lever operation detectors that detect whether or not the operating levers 13, 14, and 15 are operated, respectively.
When 4.15 is operated, operation detection signals a, b, c♀ are output.

Reference numeral 32 denotes a height calculator which receives angle signals α, β, and rv and calculates the height from the reference value of the packet 40. For example, as shown in FIG. The distance between the pivot point P1 of the boom 2 is 1, the distance between the pivot point P1 and the arm of the packet 4 [the distance between the i point P2 @ %' l 2 , the distance between the pivot point P2 and the packet tip point Pa is 1k13, from GaL Pivot point P. If the height of is keho, then the packet cutting edge point P
The height h3 of 3 is hs=ho+j l5iaα−j2sin(α+β)+
7,5in (α+β+r), and the pivot point P2
The height h2 is h2=h, +l, sin α-j
It can be calculated as 12sin(α+β).

33 is the signal a of the 1st tab operation detectors 13-15.

b, input the output signal by of the cv machining height calculator 32, and control signal T, 8 for the switches 18, 21, 27;
This is a control command device that outputs 9 signals.

The control signal T is set when at least one of the boom operating lever 13 and the 7-A operating lever 14 is operated and the packet height h (for example, the height hs of the packet cutting edge point P3) is greater than or equal to the set value. The control signal S is output when the control signal T is output and the packet operation lever J5 is not operated. That is, if expressed as a logical formula, T=(a+b)・(h)h. ) 8=T −c=(a+b ) @c −(h)h e
).

When the control signal T is output, the switch 27 is turned on, and when the control signal S is output, the switch 18.21 is turned on.

In the above-mentioned control device, either only the packet operating lever is operated, or the packet height h is equal to or less than the set value, and the boom operating lever 13 and the arm operating lever 14 are operated.
When at least one of them and the packet operation lever 15 are operated simultaneously, the control signals T and 8 from the control command device 33 are not output, so the switches 18 and 2 are not output.
1 and 27 are both off, the electromagnetic control valve 12 is switched in response to the manual operation signal of the packet operation lever 15, and the speed of the packet cylinder 7, that is, the angular velocity of the packet 40, is a value corresponding to the amount of operation of the packet operation lever 15. Become.

When the packet height h reaches the set value heL, at least one of the zoom operation lever 13 and the arm operation lever 14 is operated, and the packet operation lever l! If no operation is performed, control signals T and S are output from the control command device 33, so that both switches 18, 21, and 27 are turned on. Therefore, the velocity of the packet cylinder 7, that is, the angular velocity of the packet 4, has a value corresponding to the output steam of the adder 26+klrVc.

By the way, the absolute angle θ of packet 4 (see Figure 1) is determined by the boom angle, arm angle, and packet angle A and B, respectively.
, r and ↑ro are expressed by the following formula.

θ=, 4-1+7'+c Here, C is a constant value depending on the shape of the packet 4, etc. Therefore, since the absolute angle signal θ=α+β+γ has a value according to the absolute angle θ, in order to keep the absolute angle θ constant, it is sufficient to keep the absolute angle signal θ constant.

When the absolute angle θ is constant, that is, when the absolute angle signal θ is constant, VC is obtained by differentiating this equation as shown in the following equation.

1=-a-J Therefore, if the angular velocity of the packet 40 is set to a value according to the packet control velocity signal -&-2 7r, the packet absolute angle θ becomes a constant value. Then, due to the influence of disturbances, such as the packet 4 hitting an impact object, the characteristics of the electromagnetic control valve 12, and changes in the viscosity, temperature, and pressure of the pressure oil, the absolute angle θ changes when the operating lever 13 or 14 starts operating. When the angular velocity of the packet 40 changes from the point in time, the angular velocity of the packet 40 is corrected at a speed corresponding to Δr in accordance with the variation tlC, and the absolute angle θ of the packet 4 is kept constant.

Next, when the packet operation lever 15V is also operated in this state, only the control signal T is output from the control command device 33, so that the switch 18.2 is turned off. Therefore, packet 4 is a control speed signal; ttC manual operating device 2
Since it rotates at an angular velocity according to the signal obtained by adding the packet manual operation signal which is the output signal of No. 2, the absolute angle θ of the packet 4 can be corrected at a speed corresponding to the operation jlIVc of the packet operation lever 15.

Furthermore, when the packet operation lever 15Fa' is returned to the neutral position in this state, the control signal S is output from the control command device #33 and the switch 18.21 is turned on.
The absolute angle signal θ0 at that point in time is stored in 17, and the packet 4 is θ from then on. The absolute angle θ corresponding to is held.

Generally, during excavation, since the packet height h is smaller than the set value h6, the control command signals T and 8 are not output from the control command device 33, so the bucket angle is not controlled, and the operability during excavation is good.

When the excavation is completed in this state and the packet 4v is raised to load earth and sand, the packet height h below the ground surface is still smaller than the set value h1. Then, when the boom is raised from this state, the packet height h increases, and the packet absolute angle θ also increases, so that h>h6, the packet target absolute angle signal θ is determined. is set and thereafter controlled so that the absolute packet angle θ is constant. The set value hc is set in accordance with the most preferable packet absolute angle θ that prevents the earth and sand loaded with the packet 4Vc from falling.

According to the present invention explained above, the following effects can be achieved.

(1) Load the soil by straining the packet at an angle below the excavation diameter ground surface and raise the boom or arm? Even when the bag is moved, a favorable packet angle can be maintained to prevent dirt from falling.

(2) Even when the boom or arm is raised, manual correction of the packet angle using the packet control lever is easy and provides a good operating feel.

(3) Packet angle control is not performed during normal excavation, resulting in good operability during excavation.

[Brief explanation of the drawing]

1 to 3 relate to embodiments of the present invention, and FIG. 1 shows the front part of the loading hydraulic excavator.
2 is a diagram showing a control device for implementing the bucket angle control method of a loading shovel, and FIG. 3 is a diagram for explaining the calculation of the packet height. 1...Loading shovel body, 2...
...7'-arm, 3...rearm, 4...packet, 5...----7''-mu cylinder, 6, old...
・Arm cylinder, 7...Packet cylinder,
8,9,10... Angle meter, 12... Solenoid control valve, 13... Boom operation leno (-114
...7-A operating lever, 15...) Kukerato operating lever, 16...... Adder for adding packet absolute angle signal θ, 17... Storage device (memorizes Nokket target absolute angle θ), 18, 21.27...
. . . Switch, 22 . . . Manual operation device 52
4...Differentiator, 32...Height calculator,
33... Control command device. Figure 1 β Figure 2? Figure 3 P.

Claims (1)

[Claims] A boom that is pivotally attached to the main body and tilted up and down by a boom cylinder, an arm that is pivoted to the tip of this boom and swung by an arm cylinder, and a packet that is pivoted to the tip of this arm and rotated by a packet cylinder. In the method for controlling the packet angle of a loading shovel, the height of the packet from the reference plane is equal to or greater than a set value, and at least one of the boot operation lever and the arm operation lever is operated, and the packet operation lever is not operated. A method for controlling a kerato angle for a loading excavator, characterized in that when , the packet absolute angle signal at that time is used as a target value to control the operation of a packet cylinder.