JPH0454013B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fall prevention device for a hydraulic excavator that prevents the hydraulic excavator from falling during operation.

Hydraulic excavators can perform various types of work using their configuration. The configuration of such a hydraulic excavator will be explained below.

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 by a support shaft. The front mechanism T is composed of a boom 1, an arm 2, and a bucket 3. B is boom 1
The upper arm rotation fulcrum, C indicates the bucket rotation fulcrum on 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.

Such a hydraulic excavator performs various tasks by individually driving the boom 1, arm 2, and bucket 3 and rotating the upper revolving structure S. By the way, during such work, the front mechanism T
The moment acting on the hydraulic excavator due to the load applied to the hydraulic excavator becomes large, and there is a possibility that the hydraulic excavator may fall over. For example, when suspending a load from the tip of bucket 3, or when lifting a load with boom 1 raised and arm 2 and bucket 3 fully bent, then lowering boom 1 and extending arm 2 and bucket 3. If the moment acting on the hydraulic excavator becomes large, the hydraulic excavator may fall over. In addition, when a hydraulic excavator on a cliff is working with the front mechanism T extended to the bottom of the cliff, the moment acting on the hydraulic excavator may become large depending on the length of the front mechanism T and the load applied to it, causing the hydraulic excavator to reach the bottom of the cliff. There is a risk of falling.

Conventionally, in order to prevent the hydraulic excavator from tipping over, it was considered to issue an alarm in advance to alert the operator. Because they are driven individually, they always take on a complex shape during work, and as a result, the moment acting on the hydraulic excavator also changes in a complex manner, making it extremely difficult to constantly and accurately grasp this moment. Therefore, it is difficult to generate accurate and optimal alarms, and in order to solve this problem, it is necessary to set alarm generation conditions with maximum safety in mind. This means that even if the hydraulic excavator is actually able to withstand a much larger load, an alarm will be issued and the work will become impossible. This has the disadvantage of reducing efficiency.

The purpose of the present invention is to provide a hydraulic excavator that can solve such problems, make full use of the working capacity of the hydraulic excavator while reliably maintaining safety, and improve work efficiency. To provide fall prevention devices.

To achieve this object, the present invention includes a hydraulic excavator body consisting of a traveling body and a revolving body supported by the traveling body, a boom, an arm, and a working part attached to the tip of this arm and supported by the revolving body. A hydraulic excavator comprising a front mechanism rotatably supported by a shaft, a displacement detection device for detecting at least a displacement of the boom with respect to the revolving body and a displacement of the arm with respect to the boom; an angle detection device that detects an inclination angle of a body with respect to a horizontal plane in a direction perpendicular to the support axis; a pressure detection device that detects a driving pressure of a boom cylinder that drives the boom; the displacement detection device; and the angle detection device. and a first step in which the front mechanism determines the moment acting on the support shaft based on the value detected by the pressure detection device, and also determines the moment caused by this moment acting on the overturning support existing on the traveling body. and a second calculating means for calculating the moment that the weight of the hydraulic excavator body acts on the overturning fulcrum existing on the traveling body based on the inclination angle detected by the angle detection device and a predetermined safety factor. a calculating means; a comparing means for outputting a signal when the moment with respect to the overturning fulcrum calculated by the first calculating means exceeds the moment calculated by the second calculating means; and a signal output from the comparing means. The hydraulic excavator is characterized by being provided with an overturn prevention means for preventing the hydraulic excavator from overturning.

Furthermore, the present invention provides a hydraulic excavator main body comprising a traveling body and a revolving body supported by the traveling body;
In a hydraulic excavator, the front mechanism includes a boom, an arm, and a working part attached to the tip of the arm, and is rotatably supported on the revolving body by a support shaft, in which at least the front mechanism is connected to the boom relative to the revolving body. and a displacement detection device for detecting the displacement of the arm with respect to the boom, an angle detection device for detecting an inclination angle of the revolving body with respect to a horizontal plane in a direction perpendicular to the spindle, and a boom cylinder for driving the boom. a pressure detection device that detects the driving pressure of the boom cylinder, a first calculation means that calculates the pushing force of the boom cylinder based on the value detected by the pressure detection device, the displacement detection device, the angle detection device, the a second calculation means for calculating the pushing force of the boom cylinder that causes a possibility of overturning of the hydraulic excavator based on the value detected by the pressure detection device and a predetermined safety factor; and calculation by the first calculation means. a comparison means that outputs a signal when the extrusion force calculated exceeds the extrusion force calculated by the second calculation means; and an overturn prevention means that prevents the hydraulic excavator from overturning based on the signal output from the comparison means. It is also characterized by the fact that

The above-mentioned first invention of the present invention provides that when the front mechanism is oriented in a direction perpendicular to the traveling direction of the traveling body, a moment acts on the support shaft according to the inclination angle of the hydraulic excavator body, and this moment is applied to the traveling body. A first calculating means calculates the moment caused by the force acting on the overturning fulcrum of the body, and a second calculating means calculates the moment that the hydraulic excavator main body has, which opposes the moment generated at the overturning fulcrum, taking into account the safety factor. Find the first one by comparing the two.
When the value calculated by the first calculation means exceeds the value calculated by the second calculation means, an alarm is issued or the operation of the front mechanism is stopped.

In the invention after the present invention, when the front mechanism is oriented in a direction perpendicular to the traveling direction of the traveling body, the pushing force of the boom cylinder is determined by the first calculation means, and the inclination of the hydraulic excavator body is Depending on the angle, the pushing force of the boom cylinder that may cause the hydraulic excavator to fall is determined by considering the safety factor, and the two are compared, and the value determined by the first calculation means is the value determined by the second calculation means. When the limit is exceeded, an alarm will be issued or the front mechanism will stop operating.

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

FIGS. 2 to 5 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. 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 distance between fulcrum A and the point where a line drawn perpendicular to the straight line from fulcrum E intersects with the straight line, l ₂ is the distance between fulcrum E and the point where the line drawn perpendicular to the straight line from fulcrum E intersects with the straight line. _l3 is the vertical distance between fulcrums A and F, _l4 is the horizontal distance between fulcrums A and F, and _l5 is the distance in a straight line. 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, 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 extrusion force K ₁ of the boom cylinder, so the moment M ₁ acting on the fulcrum A is It will look like this:

M ₁ =K ₂ ×l ₅ =K ₁ sinα ₃ ×l ₅ ...(1) Here, the angle α ₃ is α ₃ = 90°−(α ₁ +α ₂ ) −tan ⁻¹ [l ₅ cos( α ₁ + α ₂ )−l ₄ /l ₅ sin(α ₁ + α
₂ ) + l ₃ ] Also, since the distance l ₅ is l ₅ = l ₁ / cos α ₂ , α ₃ = 90° − ( α ₁ + α ₂ ) − tan ⁻¹ [l ₁ cos (α ₁ + α ₂ ) − l ₄ cosα ₂ /l ₁ sin(
α ₁ + α ₂ ) + l ₃ cos α ₂ ] Therefore, the above equation (1) is M ₁ = K ₁ × l ₁ / cos _{α 2} × sin [90°−(α ₁ + α ₂ )− tan
^-1 {l ₁ cos (α ₁ + α ₂ ) − l ₄ cos _{α 2} /l ₁ sin (α ₁ + α ₂ )
+l ₃ cosα ₂ }] =K ₁ ×l ₁ /cosα ₂ ×cos [(α ₁ + α ₂ ) + tan ^-1 {l ₁
cos (α ₁ + α ₂ ) − l ₄ cos α ₂ / l ₁ sin (α ₁ + α ₂ ) + l ₃ co
sα ₂ }] =K ₁ ×l ₁ /cosα ₂ ×cosφ ……(2) However, φ=(α ₁ + α ₂ ) + tan ^-1 {l ₁ cos (α ₁ + α ₂ ) −
l ₄ cosα ₂ / l ₁ sin (α ₁ + α ₂ ) + l ₃ cos α ₂ } Since there are two boom cylinders, one on the left and one on the left, the extrusion 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 /cosα ₂ ×cosφ ...(3) Next, when the front mechanism T is in the state shown in Fig. 2, Find the moment _M2 when no load is applied (unloaded).

In FIG. 3, the same fulcrums and right 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. V is the position of the center of gravity of the arm, and the weight of the arm is _WV . 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 V, and l ₁₁ is the distance between the fulcrum C and the center of gravity position V. 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 _V・{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 a bucket The moment acting on the fulcrum A when a load is applied to 3, equation (4) is the bucket 3
Since this is the moment when no load is applied to the bucket 3, the moment M ₃ at which the load itself acting on the bucket 3 acts on the fulcrum A can be found as follows: M ₃ =M ₁ -M ₂ (5).

Here, the weight _WJ of the load applied to the bucket 3 is determined. In Fig. 4, the same fulcrum and same position as in Fig. 3,
The same lengths are given the same symbols. J is the center of gravity position of the load applied to the bucket, γ ₃ is the straight line and the straight line
The angle formed by CJ, _l12 is the horizontal distance between the fulcrum A and the center of gravity J, and _l13 is the distance between the fulcrum C and the center of gravity J.

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) Therefore, the weight W _J is W _J = M ₃ /l ₁₂ (7).

The above calculations were performed considering the moment acting on the fulcrum A from the front mechanism.
When considering the overturning of a hydraulic excavator, it is necessary to consider the moment that acts on the actual overturning fulcrum. Furthermore, since the upper revolving body S of the hydraulic excavator rotates, there may be cases where the excavator rotates with a load suspended from the bucket 3, for example. In such a case, the position of the overturning fulcrum moves depending on the orientation of the upper revolving structure S. In each embodiment of the present invention, calculations are performed regarding the overturning fulcrum when the upper revolving structure S is placed sideways, where overturning of the hydraulic excavator is most likely to occur, and the moment acting on this overturning fulcrum.

FIG. 5 shows a state in which the upper revolving structure S is facing right sideways, and the inclination angle of the revolving structure S is θ. A is the same boom rotation fulcrum as described above, L is the center of gravity position of the hydraulic excavator body (excluding the front mechanism T), and N is the tipping fulcrum. l ₁₄ and l ₁₆ are the horizontal and vertical distances between the fulcrum A and the fulcrum N, respectively, and l ₁₅ and l ₁₇ are the horizontal and vertical distances, respectively, between the fulcrum N and the center of gravity position L.

Here, if the weight of the hydraulic excavator body is W _L , the moment M ₄ due to the weight of the hydraulic excavator body at the tipping fulcrum N is M ₄ = W _L (l ₁₅ cos θ + l ₁₇ sin θ) (8). The moment acting on the hydraulic excavator body from the front mechanism, that is, the overturning moment _M5 is:
From equations (4), (5), (6), and (7), M ₅ = W _G {l ₉ cos(θ+α ₁ +α ₂ )−l ₁₄ cosθ−l ₁₆ sinθ
}+W _V {l ₆ cos(θ+α ₁ )+l ₁₀ sin(θ+α ₁ +β ₁ +β
₂ ) −l ₁₄ cosθ−l ₁₆ sinθ}+W _I {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 ) −l ₁₄ cosθ−l ₁₆ sinθ}＋W _J (l ₁₂ −l ₁₄ cosθ−l ₁₆ si
nθ) = M ₂ − (W _G + W _V + W _I ) (l ₁₄ cos θ + l ₁₆ sin θ) + M ₃ −
W _J (l ₁₄ cos θ + l ₁₆ sin θ) = M ₁ − (W _G + W _V + W _I + W _J ) (l ₁₄ cos θ + l ₁₆ sin)...
(9) From the above equations (8) and (9), overturning of the hydraulic excavator occurs when M ₅ > M ₄ . Therefore, in order to ensure safety, the moment M ₄ is multiplied by an appropriate constant C _M (however, 0<C _M <1).
M ₆ (M ₆ = C _M × M ₄ ), and this moment M ₆
and the moment _M5 , and when the moment _M5 exceeds the moment _M6 , a signal is generated. If this signal is used to prevent the hydraulic excavator from falling over, it will allow the hydraulic excavator to fully utilize its capabilities while ensuring safety. This means that you can make the most of it.

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

FIG. 6 is a block diagram of a fall prevention 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 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 output 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 output. In the figure,
7 is the calculation part of the device of this embodiment, 8 is the calculation part 7
This is an alarm device that is activated by a signal output from the The configuration of the calculation section 7 is as follows.
That is, 9 is an unladen moment calculation unit that inputs the signals E〓, E〓 ₁ , E〓 ₁ , E〓 ₁ and calculates the moment M ₂ ;
10 inputs the signals E〓 ₁ , E _pb , E _pr and calculates the moment.
Front moment calculation unit for calculating _M1 , 11
inputs the signals E〓, E〓 ₁ , E〓 ₁ , E〓 ₁ and calculates the horizontal distance l ₁₂
12 is a subtractor; 1 is a load point distance calculation unit that calculates
3 is a divider, 14 is an overturning moment calculation section that calculates the moment _M5 , 15 is a main body side moment calculation section that receives the signal E and calculates the main body side moment _M6 , and 16 is a comparator.

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 angle signal E〓 from the tilt angle detector are added in an adder 17, and this added signal E〓 ₊ 〓 ₁ is the angle stored in the memory 18. The signal E〓 ₂ of α ₂ is added to the adder 19, and the signal
Generates E〓 ₊ 〓 ₁₊ 〓 ₂ . This signal is input to the trigonometric function generator 20, and a signal E _{cps (} 〓 ₊ 〓 ₁₊ 〓 ₂₎ corresponding to the cosine of the angle (θ + α ₁ + α ₂ ) is extracted, and the coefficient unit 21 calculates the weight W _G and distance. l A signal corresponding to the value multiplied by ₉ is multiplied, and the signal E _WG

Claims (1)

[Scope of Claims] 1. A hydraulic excavator body consisting of a traveling body and a rotating body supported by the traveling body, a boom, an arm, and a working part attached to the tip of this arm, which is rotatable by a support shaft on the rotating body. A hydraulic excavator includes a front mechanism that is dynamically supported, and a displacement detection device that detects at least a displacement of the boom with respect to the rotating body and a displacement of the arm with respect to the boom; An angle detection device that detects an inclination angle with respect to a horizontal plane in a direction perpendicular to an axis, a pressure detection device that detects a driving pressure of a boom cylinder that drives the boom, the displacement detection device, the angle detection device, and the pressure detection device. a first calculating means for calculating the moment acting on the support shaft by the front mechanism based on the value detected by the device, and calculating the moment due to this moment acting on an overturning support existing on the traveling body; , a second calculation means for calculating a moment exerted by the weight of the hydraulic excavator body with respect to an overturning fulcrum existing on the traveling body based on the inclination angle detected by the angle detection device and a predetermined safety factor; a comparison means for outputting a signal when the moment with respect to the overturning fulcrum calculated by the first calculation means exceeds the moment calculated by the second calculation means; A fall prevention device for a hydraulic excavator, characterized in that it is provided with a fall prevention means for preventing the fall. 2. A hydraulic excavator body consisting of a traveling body and a revolving body supported by this traveling body, and a front end rotatably supported by a pivot on the said revolving body, consisting of a boom, an arm, and a working part attached to the tip of this arm. a displacement detection device for detecting at least a displacement of the boom with respect to the rotating body and a displacement of the arm with respect to the boom; an angle detection device that detects the inclination angle of the boom with respect to a horizontal plane; a pressure detection device that detects the driving pressure of a boom cylinder that drives the boom; and a push force of the boom cylinder based on the value detected by the pressure detection device. a first calculating means for calculating, and a first calculating means for calculating the possibility of overturning of the hydraulic excavator based on the values detected by the displacement detecting device, the angle detecting device, the pressure detecting device, and a predetermined safety factor. a second calculation means for calculating an extrusion force; a comparison means for outputting a signal when the extrusion force calculated by the first calculation means exceeds the extrusion force calculated by the second calculation means; 1. A fall prevention device for a hydraulic excavator, comprising a fall prevention means for preventing the hydraulic excavator from falling based on a signal output from a comparison means.