JPH03456B2 - - Google Patents

Description

DETAILED DESCRIPTION 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.

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. 1 is a side view of a schematic configuration of a 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 a 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 onto a waiting dump truck, the hydraulic excavator drives the boom 1, arm 2, and bucket 3 as appropriate to load the excavated soil into the bucket 3. The excavated earth and sand are loaded, 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 limestone is charged into a reactor in a chemical plant. In such cases, the weight of limestone required for the reaction is set at a predetermined amount, so the procedure is to weigh the limestone once and then introduce it with a hydraulic shovel, which requires a lot of effort and time. It required

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

In order to achieve this object, the present invention detects the displacement amount of at least the boom and arm of the front mechanism of a hydraulic excavator, and also detects the driving pressure of the boom cylinder, arm cylinder, etc. at the same time,
Furthermore, the inclination angle of the revolving structure is also detected, the load amount of the front mechanism is calculated based on these detected values, and the calculated load amount is applied each time the load moves once or multiple times. The feature is that the movement is accumulated and displayed.

Hereinafter, the present invention will be explained based on illustrated embodiments.

FIGS. 2 to 4 are explanatory diagrams for explaining the calculations of the calculation unit 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. Also, x,
h are a horizontal axis and a vertical axis when viewed from the ground with the boom rotation fulcrum A as the center, respectively, and the horizontal axis x and the vertical axis h constitute a coordinate axis with the rotation fulcrum A as the origin. X and H indicate a horizontal axis and a vertical axis, respectively, when viewed from the rotating structure S that is inclined by an angle θ with the boom rotation fulcrum A as the center. In this case, the illustrated angle θ is the angle when the rotating body S is inclined toward the side opposite to the front mechanism T, and conversely, the angle θ is the angle when the rotating body S is inclined toward the side of the front mechanism T. The angle is negative. α ₁ is the boom angle between the horizontal plane at fulcrum A and a 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 arm angle obtained by subtracting 90° from the angle between the straight line and the straight line on arm 2, and γ ₁ is the bucket angle between the straight line and the straight line on bucket 3. l ₁ is the straight line distance, l ₂ is the distance between fulcrum E and the point where a line drawn horizontally from fulcrum E intersects the straight line, l ₃ is the horizontal distance between fulcrum A and fulcrum F, l ₄ is the vertical distance between fulcrum A and fulcrum F. P _b is the bottom side pressure of the boom cylinder 4 , P _r is the rod side pressure of the boom cylinder 4 , S _b is the bottom side pressure receiving area of the boom cylinder 4 , and S _r 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. Note that since two boom cylinders 4 are normally used, it is assumed that two boom cylinders 4 are provided in this embodiment as well.
All moments are considered centered around 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 _K2 of the boom cylinder's pressing force _K1 , so the moment _M1 acting on the fulcrum A is It will look like this:

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
×cosφ……(2) However, φ=(α ₁ +α ₂ )+tan ^-1 {l ₁ cos(α ₁ +α ₂ )−l ₄ /l ₁
sin (α ₁ + α ₂ ) + l ₃ } Since there are two boom cylinders, one on the left and one on the left, the pressing force K ₁ of the boom cylinder is calculated as follows: K ₁ = 2 × (P _b・S _b −P _r・S _r ) Therefore, equation (2) becomes as follows.

M ₁ = 2 (P _b・S _b −P _r・S _r ) × l ₁ × cosφ……(3) This moment M ₁ is acting on the hydraulic excavator body when there is a load in the bucket 3. It's a moment. From the above equation, it can be seen that the inclination angle θ of the rotating body S is not related to the calculation of the moment _M1 .

Next, when the front mechanism T is in the state shown in FIG. 2, the moment _M2 is determined when there is no load on the bucket 3 (that is, when there is no load on the bucket 3).

In FIG. 3, the same fulcrums and the same angles as in FIG. 2 are given the same symbols. G is the boom center of gravity position, and the weight of the boom is W _G. N is the position of the center of gravity of the arm, and W _N is the weight of the arm. I is the center of gravity of the bucket, and the weight of the bucket is W _I. α ₄ is the angle between straight lines, β ₂ is the angle between straight lines, and γ ₂ is the angle between straight lines. l ₆ is the length of the straight line, l ₇
is the length of the straight line, l ₈ 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 N, and l ₁₁ is the distance between the fulcrum C and the center of gravity position N. This is the distance from the center of gravity position I.

As defined above, the moment M ₂ when the load is empty is M ₂ = W _G・l ₉ cos(θ+α ₁ +α ₂ )+W・{l ₆ cos(θ+α
₁ ) + l ₁₀ sin (θ + α ₁ + β ₁ + β ₂ )} +W ₁ {l ₆ cos (θ + α ₁ ) + l ₇ sin (θ + α ₁ + β ₁ ) − l
₁₁ sin(θ+α ₁ +β ₁ +γ ₁ +γ ₂ )}...(4) Equation (3) is the moment acting on the fulcrum A when there is a load on bucket 3, and equation (4) is when there is no load on bucket 3. Therefore, the moment of the load itself acting on the fulcrum A
M ₃ is obtained by M ₃ =M ₁ −M ₂ (5).

Here, the weight W _J of the cargo in the bucket 3 is determined.
In FIG. 4, 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, γ ₃ is the angle between two straight lines, l ₁₂ is the horizontal distance between the fulcrum A and the center of gravity J, and l ₁₃ is the distance between the fulcrum C and the center of gravity J. It is distance.

When determined as above, the distance l ₁₂ is: l ₁₂ = l ₆ cos (θ + α ₁ ) + l ₇ sin (θ + α ₁ + β ₁
) − l ₁₃ sin (θ + α ₁ + β ₁ + γ ₁ + γ ₃ )...(6), and the weight W _J of the cargo in the bucket 3 is W _J = M ₃ / l ₁₂ (7).

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

FIG. 5 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 determine the boom angle α ₁ , arm angle β ₁ , and bucket angle γ ₁
is detected, and the signals E〓 ₁ , E〓 1 , E〓 ₁ ,
E〓 ₁ is 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 P r corresponding} to these pressures are provided.
E _pr is detected from each pressure sensor. Furthermore, the rotating body S is provided with an inclination angle detector, and the rotating body S
A signal E〓 corresponding to the inclination angle θ is eluted. In the figure,
7 is the calculation part of the device of this embodiment, 8 is the calculation part 7
A display section, 8a, operated by a signal output from the
is its display surface. The configuration of the calculation section 7 is as follows. That is, 9 is the signal E〓, E〓 ₁ , E〓 ₁ ,
10 is a front moment calculation unit that inputs signals E〓 _{1 ,} E _{pb ,} E _pr and calculates moment M ₁ , 11 is a signal E 〓 ₁ , E 〓 ₁ , E 〓 ₁ is input to calculate the horizontal distance l ₁₂ Load point distance calculating section 12
13 is a subtracter, 13 is a divider, 14 is an integration storage unit that integrates and stores the load amount from the divider 13, and 15
16a is a display changeover switch that switches and displays the loading amount for each load and the accumulated loading amount, and 16a is a signal.
A load amount calculation switch 16b outputs E _C to calculate the load amount, and 16b is a memory erasing switch that outputs a signal E _Q to erase the memory of the integration memory 14.

The operation of this embodiment will be explained below.

First, the operation of the unloaded moment calculation unit 9 is
A description will be given based on a block diagram showing a specific example of the empty load moment calculating section shown in the figure. The boom angle signal E〓 ₁ from the angle detector and the tilt signal E〓 from the tilt angle detector are added in an adder 17, and this added signal E〓 ₊ 〓 ₁ and the angle α stored in the memory 18 ₄ signals
E〓 ₄ is added in adder 19, and the signal E〓 ₊ 〓 ₁₊ 〓 ₄
occurs. This signal is input to the trigonometric function generator 20, and a signal corresponding to the cosine of the angle (θ+α ₁ +α ₄ ) is
E _cps( 〓 ₊ 〓 ₁₊ 〓 ₄₎ is taken out, and the weight is calculated by the coefficient unit 21.
A signal corresponding to the value of W _G multiplied by distance l ₉ is multiplied,
Signal E _WG

Claims (1)

[Claims] 1. A front panel consisting of a traveling body, a rotating body supported by the traveling body, a boom, an arm, and a working part attached to the tip of the arm, with the end of the boom rotatably attached to the rotating body. A hydraulic excavator comprising a mechanism, a displacement detection device that detects displacement of at least a boom and an arm of the front mechanism, and a pressure detection device that detects pressure of at least one of hydraulic cylinders that operate the front mechanism, an inclination angle detection device that is installed at the attachment part of the boom and detects the inclination angle in the front direction of the rotating body; 1. A load amount display device for a hydraulic excavator, comprising a calculation means for determining the amount of load on a front mechanism, and a display section for displaying a value related to the amount of load determined by the calculation means.