JPH0444930B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a load amount display device for a hydraulic excavator that calculates and displays the weight of a load in a front mechanism of a hydraulic excavator.

[Background of the invention]

Hydraulic excavators can perform various types of work using their configuration. Among these operations, one that is frequently performed is the operation of moving heavy objects from one location to another. A typical example of this work will be explained with reference to the configuration of a hydraulic excavator shown in FIG.

FIG. 2 is a side view of the schematic configuration of the hydraulic excavator. In the figure, R is a lower traveling body, S is an upper rotating body on the lower traveling body R, and T is a front mechanism rotatably attached to the boom rotation fulcrum A of the upper rotating body S. The front mechanism T is composed of a boom 1, an arm 2, and a bucket 3. B indicates the arm rotation fulcrum on the boom 1, C indicates the bucket rotation fulcrum on the arm 2, and D indicates the tip of the bucket. 4 is a boom cylinder that raises and raises the boom 1; 5 is an arm cylinder that swings the arm 2; and 6 is a bucket cylinder that rotates the bucket 3. Note that F indicates the bottom fulcrum of the boom cylinder 4, and E indicates the rod fulcrum of the boom cylinder 4.

When considering the work of excavating the ground and loading the excavated earth and sand onto a waiting dump truck, the hydraulic excavator drives the boom 1, arm 2, and bucket 3 as appropriate. The excavated earth and sand are loaded inside, the upper revolving body S is rotated, the bucket truck 3 is moved to the dump truck, and the earth and sand is loaded onto the dump truck.

Conventionally, when carrying out such work, the recognition of the weight of the earth and sand loaded onto the dump truck relied exclusively on visual estimation by the worker. On the other hand, dump trucks have a fixed rated loading weight, so when loading by visual inspection as described above, it is common for dump trucks to be overloaded or underloaded than the rated loading weight. Ta. Therefore, if too much earth and sand is loaded, problems such as breakdowns, accidents, and shortened lifespans of the dump truck may occur, while if too little is loaded, the work efficiency is reduced.

Another example of work in which heavy objects are moved using a hydraulic shovel is, for example, work in which a large amount of coal rock is charged into a reactor in a chemical plant. In such cases, the weight of coal rock required for the reaction is set at a predetermined amount, so the procedure is to weigh the coal rock once and then introduce it with a hydraulic shovel, which requires a lot of time and effort. It took time.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic excavator load amount display device that solves the above-mentioned conventional problems and allows the user to know the weight of a hydraulic excavator's load.

[Summary of the invention]

In order to achieve this object, the present invention includes a traveling body, a revolving body supported by the traveling body, a boom,
A hydraulic excavator comprising an arm and a front mechanism comprising a working part attached to the tip of the arm and rotatably supported by the revolving body, a displacement detection device for detecting displacement of at least the boom and the arm of the front mechanism; , a pressing force detection device that detects the pressing force of at least one of the hydraulic cylinders that operate the front mechanism, and calculating a moment of the front mechanism based on each detected value of the displacement detection device and the pressing force detection device. a first calculating means, an attitude setting device for setting a predetermined attitude of the front mechanism, and a first attitude setting device for setting a predetermined attitude of the front mechanism; a second calculating means for calculating a correction value of the no-load moment based on the calculated value of the calculating means and the no-load moment obtained from the displacement detection position and the component of the front mechanism in the set posture; a third calculating means for calculating the load amount of the front mechanism based on the no-load moment corrected with the correction value obtained by the second calculating means and the calculated value of the first calculating means; cargo load calculation command means for instructing the calculation means to calculate the cargo load when the front mechanism assumes the set attitude; and a display section for displaying a value related to the cargo load calculated by the third calculation means. It is characterized by having the following.

[Embodiments of the Invention] The present invention will be described below based on illustrated embodiments.

FIGS. 3 and 4 are explanatory diagrams for explaining calculations in the calculation section of the embodiment of the present invention.

In Figure 2, A, B, C, D, E, and F are the boom rotation fulcrum, arm rotation fulcrum, bucket rotation fulcrum, bucket claw tip, boom cylinder rod fulcrum, and boom cylinder bottom shown in Figure 1. Indicates the fulcrum. α ₁ is the boom angle between the horizontal plane at fulcrum A and the straight line on boom 1, α ₂ is the angle between the straight lines, α ₃ is the angle between the boom cylinder rod and the straight line, β ₁ is the straight line and the arm The arm angle is the angle with the straight line on 2 minus 90 degrees, and γ ₁ is the bucket angle between the straight line and the straight line on bucket 3. l ₁ is the distance in a straight line, l ₂ is the distance between fulcrum E and the point where a line drawn perpendicular to the straight line from fulcrum E intersects with the straight line, l ₃ is the vertical distance between fulcrum A and fulcrum F, and l ₄ is This is the horizontal distance between fulcrum A and fulcrum F.
Pb is the bottom side pressure of the boom cylinder 4, Pr is the rod side pressure of the boom cylinder 4, and Sb is the bottom side pressure receiving area of the boom cylinder 4. Sr is the rod side pressure receiving area of the boom cylinder 4. K ₁ indicates the pushing force of the boom cylinder 4, and K ₂ indicates the corresponding force. In addition,
Since two boom cylinders 4 are normally used, it is assumed that two boom cylinders 4 are provided in this embodiment as well, and all moments are assumed to be centered around the fulcrum A.

In this state of the front mechanism T of the hydraulic excavator, the rotational moment by the front mechanism T is supported by the component force K ₂ of the pressing force K ₁ of the boom cylinder, so the moment M ₁ acting on the fulcrum A is becomes as follows.

M ₁ =K ₂ ×l ₁ =K ₁ sinα ₃ ×l ₁ ...(1) Here, the angle α ₃ is α ₃ = 90° - (α ₁ + α ₂ ) - tan ^-1 [l ₁ cos (α ₁₊
α ₂ ) − l ₄ / l ₁ sin (α ₁ + α ₂ ) + l ₃ ] Therefore, the above equation (1) is M ₁ = K ₁ × l ₁ × sin [90° − (α ₁ + α ₂ ) − tan ^-1 {l ₁ cos
(α ₁ + α ₂ ) − l ₄ / l ₁ sin (α ₁ + α ₂ ) + l ₃ }] = K ₁ × l ₁ cos [(α ₁ + α ₂ ) + tan ^-1 {l ₁ cos (α ₁ + α
₂ ) − l ₄ / l ₁ sin (α ₁ + α ₂ ) + l ₃ }] = K ₁ × l ₁ × cosθ
...(2) However, θ = (α ₁ + α ₂ ) + tan ^-1 {l ₁ cos (α ₁ + α ₂ ) − l ₄ / l ₁ sin (α ₁ + α ₂ ) +
l Since there are _two boom cylinders, one on each side, the pushing force K ₁ of the three boom cylinders is K ₁ = 2 × (Pb・Sb−Pr・Sr) Therefore, equation (2) is as follows. become.

M ₁ =2(Pb・Sb−Pr・Sr)×l ₁ ×cosθ (3) This moment M ₁ is the moment acting on the hydraulic excavator body when there is a load in the bucket 3.

In the above manner, the moment _M1 when there is a load in the bucket 3 can be found, but in order to find the weight of the load in the bucket 3, the moment at the fulcrum A due to the weight of the cargo itself must be calculated between the fulcrum A and the load. It is necessary to divide by the distance between the center of gravity of

First, the calculation of the distance between the fulcrum A and the center of gravity of the load will be explained based on FIG. 4. In the figure, the same fulcrums, the same positions, and the same lengths as in FIG. 3 are given the same symbols. J is the position of the center of gravity of the load on the bucket, r ₃ is the angle between two straight lines,
l ₅ is the length of the straight line, l ₆ is the length of the straight line, l ₃ is the horizontal distance between the fulcrum A and the center of gravity position J, and l ₇ is the fulcrum C.
and the center of gravity J.

When determined as above, the distance l ₈ becomes l ₈ = l ₅ cosα ₁ + l ₆ sin (α ₁ + β ₁ ) − l ₇ sin (α ₁ + β ₁ + r ₁ + r ₃ ) (4).

Next, let us find the moment at the fulcrum A due to the weight of the load itself. This moment is calculated from the moment M ₁ obtained by equation (3), and the front mechanism when there is no load in the bucket 3 is calculated as the moment (no-load moment, this moment is
Let's call it Moc. ) can be obtained by subtracting. Hereinafter, the calculation of the moment and Moc will be explained based on FIG. 5. In the figure, the same fulcrum, the same angle, and the same length as in FIG. 4 are given the same reference numerals. G is the boom center of gravity position, and the weight of the boom is W _G. H is the position of the center of gravity of the arm, and W _H is the weight of the arm.
I is the center of gravity of the bucket, and the weight of the bucket is
Let it be W ₁ . α ₄ is the angle between two straight lines, β ₂
is the angle between two straight lines, and r ₂ is the angle between two straight lines. l ₅ is the length of the straight line, l ₃ is the length of the straight line, l ₉ is the distance between the fulcrum A and the center of gravity position G, l ₁₀ is the distance between the fulcrum B and the center of gravity position H,
l ₁₁ is the distance between the fulcrum C and the center of gravity position I.

As defined above, the moment Moc when unloaded is: Moc=W _G・l ₉ cos (α ₁ + α ₄ ) + W _H・{l ₅ cos _{α 1} + l ₁₀ sin (α ₁ + β ₁ + β ₂ )} +W ₁ {l ₅ cosα ₁ +l ₆ sin (α ₁ + β ₁ ) −l ₁₁ sin (α ₁ + β ₁ + γ ₁ + r ₂ ) ...(5) In this way, the no-load moment can be calculated by calculation.
M _pc is required.

By the way, the moment M ₁ in the above equation (3) is
Considering the case where there is no cargo loaded in the bucket 3, the no-load moment (this moment
Let M _p . ) is nothing but itself. Therefore, the no-load moment M _pc determined by the above equation (5)
and the no-load moment M _p determined by the above equation (3) should be theoretically equal. however,
The two values actually differ due to various errors, the adhesion of earth and sand to the bucket, etc. Therefore, in this embodiment, the actual no-load moment M _pc is calculated without using the value of the no-load moment M pc calculated above.
M _pc is used to accurately calculate M _pc by correcting a given constant used when calculating the no-load moment M _pc . As a correction means, a case is shown in which the weight _W1 of the bucket bag, which has a large influence on the front moment, is corrected.
Now, assuming that the difference between both no-load moments M _p and M _pc is entirely due to the difference in bucket weight, the difference in bucket weight ΔW ₁ can be obtained from the following equation.

ΔW ₁ =(M _p −M _pc )/l ₁₂ (6) where l ₁₂ is the horizontal distance between the fulcrum A and the bucket center of gravity position I, and is calculated as follows.

l ₁₂ = l ₅ cosα ₁ + l ₆ sin (α ₁ + β ₁ ) −l ₁₁ sin (α ₁ + β ₁ + γ ₁ + γ ₂ ) Correct the bucket weight W _I in equation (5) by this value ΔW _I , Corrected bucket weight (W _I +
The calculation is performed by using ΔW _I ) in place of the bucket weight W _I . Below, the difference ΔW _I
It is expressed as the no-load moment M _pc1 corrected by .

Now, in this way, the accurate no-load moment M _pc1 can be found. And, as mentioned above,
The weight of the cargo in the bucket 3 (this weight is designated as W) is obtained by dividing the moment acting on the fulcrum A due to the weight of the cargo itself by the distance _l8 between the fulcrum A and the center of gravity of the cargo. Also, the moment due to the weight of the cargo itself can be obtained by subtracting the no-load moment M _pc1 from the moment M ₁ , so the weight W of the cargo in the bucket 3 is W = M _I - It can be obtained as M _pc1 /l ₈ ...(7).

When performing the above calculations, a cargo calculation commanding means may be provided, and the operator may operate the means by pressing a button or the like as appropriate to command the calculation of the cargo load amount or the cargo. Although the mechanism can be sufficiently achieved in this manner, a more preferable embodiment is as follows. That is, in this embodiment, a certain posture taken by the front mechanism during loading work of a hydraulic excavator will be considered. Here, a certain posture of the front mechanism refers to the shape of the front mechanism when the boom angle and arm angle are each at a certain predetermined angle, or when the boom angle, arm angle, and bucket angle are each at a certain predetermined angle. say. In this manner, considering a certain posture of the front mechanism, first, with the bucket bag 3 empty, the same operation as the loading operation to be performed later is performed. Then, when the front mechanism adopts the certain attitude considered earlier, the attitude setting signal memorizes the boom angle and arm angle at that time, and also stores the moments M _pc , M _p , and distance at that time.
l ₁₂ is calculated, and the difference ΔW _I is calculated using the above equation (6) and stored. Thereafter, in the loading operation of the hydraulic excavator, the calculation of the above equation (7) is performed every time the front mechanism assumes the above posture to obtain the weight W of the load. In this way, one worker can
It is no longer necessary to issue a command to calculate the load amount using a push button or the like every time the loading operation is carried out.

Examples of the present invention based on such calculations will be described below.

FIG. 1 is a block diagram of a load amount display device for a hydraulic excavator according to an embodiment of the present invention. In this embodiment, angle detectors are provided at each of the pivot points A, B, and C, and these angle detectors detect the boom angle α ₁ , the arm angle β ₁ , and the bucket angle γ ₁ . Corresponding signals Eα ₁ , Eβ ₁ , Eγ ₁ are output. Further, pressure detectors are provided to detect pressures P _b and _Pr on the bottom side and rod side of the boom cylinder 4, and signals E _pb and E _pr corresponding to these pressures are output from each pressure detector. In the figure, 7 is the calculation unit of the device of this embodiment, and 8 is the no-load moment M _pc1.
an attitude setting signal generator which determines the set attitude in order to obtain the above-mentioned attitude; 9 is a display section which is activated by a signal output from the calculation section 7 to display the load amount; 9a is a numerical display surface thereof; 9b is a display section on the numerical display surface 9a; This is a buzzer that alerts you to the display. The attitude setting signal generator 8 will be further explained. The hydraulic excavator operator must use the bucket 3 before starting loading work.
When the machine is empty, it performs the same operation as the loading operation that will be performed later. Then, with the front mechanism in an appropriate posture, the posture setting signal generator 8 is activated by a push button or the like. At this time, the attitude setting signal generator 8 outputs a signal _Es , and the above-mentioned difference ΔW _I and the attitude of the front mechanism at that time are stored by this signal. In this embodiment, the set posture of the front mechanism is defined by the boom angle α ₁ and arm angle β ₁ at that time.

The calculation unit 7 is configured as shown in the figure. That is, 1
0 is the signal Eα ₁ , Eβ ₁ , Eγ ₁ according to the angles α ₁ , β ₁ , γ ₁
11 is a front moment that calculates the moment M ₁ by inputting the signal Eα ₁ and the signals E _pb and E _pr corresponding to _the pressures P _b and _Pr . This is the calculation section. 12 is a signal
When Eα ₁ , Eβ ₁ and the signal E _s from the attitude setting signal generator 8 are input, the signals Eα ₁ and Eβ ₁ input at that time are memorized, and the memorized signals and the front mechanism are The signals Eα ₁ and Eβ ₁ that are input while changing due to movement are compared, and the signals Eα ₁ ,
This is a set attitude determination unit that generates a computation command signal E _c when Eβ ₁ becomes approximately equal to the stored signal. Reference numeral 65 denotes a no-load moment calculation unit which inputs the signals Eα ₁ , Eβ ₁ , Eγ ₁ and the correction signal EΔW _I according to the above-mentioned difference ΔW _I , and outputs the distance l ₁₂ and the no-load moment signals E _Mpc and E _Mpc1 . be. 66 inputs the signal E _M1 of the front moment calculation section 11 and the signal E _Mpc of the no-load moment signal calculation section ₆₅ , and
−E This is an adder that calculates _Mpc . A divider 67 divides the signal E _M1-Mpc of the adder 66 by the signal E _l12 when the signal E _s from the attitude setting signal generator 8 is input, and outputs the correction signal EΔ _WI . 14 is the signal E _M1 of the front moment calculation unit 11 to the calculation unit 6
An adder 15 calculates the signal E _Mpc1 of 5 and outputs the signal E _M1-Mpc1 . 15 divides the signal E _M1-Mpc1 of the adder 14 by the signal E _l8 of the load point distance calculation section 10 to obtain the load amount W. This is a divider that outputs a corresponding signal E _W. 1
6 and 17 are accumulation storage devices, and the accumulation storage device 16 is used, for example, as a storage device for storing the accumulated weight of cargo loaded onto one dump truck.
7 is used, for example, as a storage device for storing the cumulative weight of cargo over a predetermined period (one day, one week, one month, etc.). 18 and 19 are integration storage units 16 and 17, respectively.
This is a memory erase switch that erases the values stored in the memory. Reference numeral 20 denotes a display changeover switch having terminals connected to the divider 15 and integration memories 16 and 17, and by switching the switch, a desired display is made on the display section 9.

The operation of this embodiment will be explained below.

First, the operation of the load point distance calculation section 10 shown in FIG. 1 will be explained based on a block diagram showing a specific example of the load point distance calculation section shown in FIG. The boom angle signal Eα ₁ is input to the trigonometric function generator 21 and a signal E _cps α ₁ corresponding to the cosine of the angle α ₁ is extracted.
2 is multiplied by a signal corresponding to the distance _l5 , and the signal E _l5cps 〓 ₁
becomes. On the other hand, the arm angle signal E〓 ₁ is added to the boom angle signal in the adder 23, and the added signal is
E〓 ₁ + β ₁ is input to the trigonometric function generator 24, and a signal E _sio (α ₁ + β ₁ ) corresponding to the sine of the angle (α ₁ + β ₁ ) is taken out. ₆ is multiplied by a signal corresponding to E _l6sio (α ₁ +β ₁ ).
This signal is the output signal of the coefficient multiplier 22 and the adder 2.
6, and the signal E _l5cps 〓 _1+l6sio (α ₁ + β ₁
)
is obtained. Also, bucket angle signal E〓 ₁ is adder 2
7, it is added to the output signal E〓 ₁₊ 〓 ₁ of the adder 23 to become E〓 ₁₊ 〓 ₁₊ 〓 ₁ , and further, in the adder 28, the signal E corresponding to the angle γ ₃ stored in the memory 29 is added. 〓 ₃ is added and becomes the signal E 〓 ₁₊ 〓 ₁₊ 〓 ₁₊ 〓 ₃ . This signal is input to the trigonometric function generator 30 to calculate the angle (α ₁ +β ₁ +γ ₁ +
A signal corresponding to the sine of γ ₃ ) is extracted, and this signal is multiplied by a signal corresponding to the distance l ₇ in a coefficient multiplier 31 to become a signal E _l7sio (α ₁ +β ₁ +γ ₁ +γ ₃ ). This signal is subtracted from the output signal of adder 26 by adder 32 to output signal E _l8 . This signal E _l8 is a signal corresponding to the horizontal distance between the fulcrum A and the center of gravity position J shown in equation (4).

Next, the operation of the front moment calculation section 11 shown in FIG. 1 will be explained based on the block diagram showing a specific example of the front moment calculation section shown in FIG. Boom angle signal E〓 ₁ is stored in adder 34 and memory 3
It is added to the signal E〓 ₂ corresponding to the angle α ₂ stored in 3 to become the signal E〓 ₁₊ 〓 ₂ , which is input to the trigonometric function generator 35 to generate a signal according to the sine of the angle (α ₁ + α ₂ ). E _sio
(α ₁ + α ₂ ) is extracted, and the distance
The signal corresponding to _l1 is multiplied and the signal E _l1sio (α ₁ + α ₂ )
becomes. This signal is added in the adder 38 with the signal corresponding to l ₃ stored in the memory 37 to generate the signal E _l1sio (α ₁ +α ₂ )+l ₃ . On the other hand, the output signal of the adder 34 is input to the trigonometric function generator 39, which generates a signal E _cps ( 〓 ₁ + 〓 ₂ ) corresponding to the cosine of the angle (α ₁ + α ₂ ).
₎
is taken out and multiplied by a signal corresponding to the distance l ₁ by the coefficient multiplier 40, resulting in a signal E _l1cps( 〓 ₁₊ 〓 ₂₎ . This signal is subtracted in an adder 41 by a signal E _l4 corresponding to the value _l4 stored in a memory 42, and a signal E _l1cps (α1
+α2)-l4 is output. The output signal of the adder 41 is divided by the output signal of the adder 38 in a divider 43, and a signal corresponding to the quotient is input to an inverse trigonometric function generator 44, which generates a signal corresponding to the arctangent of the angle of this signal. Etan ^-1 {l ₁ cos (α ₁ + α ₂ ) − l ₄ /l ₁ sin (α ₁ + α ₂
)+l ₃ } is extracted. This extracted signal is added to the output signal E〓 ₁₊ 〓 ₂ of the adder 34 in an adder 45 to become a signal E〓. This signal is input to the trigonometric relation generator 46 to extract the signal E _cps 〓 corresponding to the cosine of the angle θ, and is multiplied by the signal corresponding to the value _2l1 in the coefficient multiplier 47 to obtain the signal E _2l1cps 〓. . On the other hand, the bottom side pressure signal E _pb of the boom cylinder 4 is guided to the coefficient multiplier 48 and multiplied by a signal corresponding to the value S _b , resulting in a signal E _pb

Claims (1)

[Claims] 1. A traveling body, a rotating body supported by the traveling body, and a front mechanism that is rotatably supported by the rotating body and includes a boom, an arm, and a working part attached to the tip of the arm. a displacement detection device that detects displacement of at least a boom and an arm of the front mechanism; a pressing force detection device that detects a pressing force of at least one of the hydraulic cylinders that actuate the front mechanism;
a first calculation means for calculating a moment of the front mechanism based on each detection value of the displacement detection device and the pressing force detection device; a posture setting device for setting a predetermined posture of the front mechanism; The calculated value of the first calculation means in the set posture set by the posture setting device when the front mechanism is unloaded, and the calculated value obtained from the displacement detection device and the components of the front mechanism in the set posture. a second calculation means for calculating a correction value of the no-load moment based on the no-load moment obtained by the second calculation means; and a no-load moment corrected by the correction value obtained by the second calculation means, and a third calculating means for calculating the load amount of the front mechanism based on the calculated value;
cargo load calculation command means for instructing the calculation means to calculate the cargo load when the front mechanism assumes the set attitude; and a display section for displaying a value related to the cargo load calculated by the third calculation means. A load amount display device for a hydraulic excavator, characterized by being provided with. 2. In claim 1, the load amount calculation command means includes a first storage unit that holds the boom angle set by the attitude setting device, and a boom angle detected by the displacement detection device. a first comparison unit that outputs a signal when the angle is within the permissible range of the set angle; a second storage unit that holds the angle of the arm set by the attitude setting device; and the displacement detection device. a second comparison section that outputs a signal when the arm angle detected by is within the set angle tolerance; and a signal is simultaneously output from the first comparison section and the second comparison section. 1. A payload display device for a hydraulic excavator, comprising: output means for outputting a signal for commanding payload calculation.