JP2003166909A - Strength evaluation method for work machine, strength evaluation system, apparatus and program for conducting strength evaluation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately evaluate the strength of front structure by in-place tests. <P>SOLUTION: A hydraulic shovel 20 is tested in-place by a specific operation pattern, and stress σ<SB>1</SB>of each part of front is detected with a stress detector 4. A hydraulic shovel 30 of the same model as the hydraulic shovel 20 is tested in-place to detect operation pattern of the hydraulic shovel 30 and stress σ<SB>2</SB>of each part of front with a stroke sensor 31 and a pressure sensor 32. With the stress σ<SB>1</SB>and σ<SB>2</SB>, a correction coefficient α corresponding to the operation pattern is calculated. A hydraulic shovel 10 of the same class as the hydraulic shovel 20 and 30 is tested in-place with a specified operation pattern to detect the stress σ<SB>1</SB>of each part of front by a stress detector 4, and the stress σ<SB>1</SB>is corrected with a correction coefficient α and stress σA, after correction is obtained. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work machine strength evaluation method, a strength evaluation system, a strength evaluation device, and a strength evaluation program for a work machine for evaluating the strength of a hydraulic excavator or the like based on a load test in a field. Regarding

[0002]

2. Description of the Related Art For example, when evaluating the strength of a front structure such as a hydraulic excavator, the hydraulic excavator is actually operated at the work site to measure the stress at each part of the front, and the strength is evaluated based on the stress measurement value. It was In addition, if there are a wide variety of measurement items such as prototype tests and it is not efficient to perform the test at the work site, a load test imitating the actual operating condition is performed in the site, and the strength is determined based on the test result. I was doing an evaluation.

[0003]

However, the on-site test is a test imitating the actual operating condition, and it is difficult to accurately evaluate the strength of the front structure by the on-site test. In other words, in general, tests are often conducted under stricter conditions in the field than in actual operation.If the strength of a structure is evaluated based on the results of this field test, it means that the safety factor has been set excessively, and the optimum shape design Can't do.

An object of the present invention is to provide a strength evaluation method for a working machine, a strength evaluation system, a strength evaluation device, and a program for strength evaluation, which can accurately evaluate the strength of a structure by an in-field test. Especially.

[0005]

[Means for Solving the Problems] 1. The invention according to claim 1 evaluates the strength of the first type working machine based on the test results of the first type working machine and the second type working machine. A method for evaluating the strength of a working machine, comprising: (1) detecting the standard stress of each part of the working machine by an in-field test of the working machine of the second type according to the standard operation pattern; and (2) the working machine of the second type. Detects the actual work stress of each part of the working machine when the actual work is performed by (3) calculates and stores a correction coefficient based on the stress and the actual work stress, and (4) standard operation pattern The standard stress of each part of the working machine is detected by the field test of the first type working machine according to the above, and (5) this stress detection value is corrected by the correction coefficient, and the stress of the first type is corrected based on the corrected stress. The above-mentioned object is achieved by evaluating the strength of the working machine. 2. The invention according to claim 2 is the strength evaluation method for a working machine according to claim 1, wherein (1) an operation when an actual work is performed on-site by the second type working machine, ) Second
The detection result of the standard stress and the detection result of the actual work stress of the types of working machines are compared under the same operation, and the correction coefficient is set for each operation. 3, The strength evaluation system for a working machine according to the invention of claim 3 performs the field test according to the standard operation pattern.
Type of work equipment, the second type of work equipment performing in-field testing and actual work in accordance with the standard operation pattern, and standard stress of each part of work equipment by the in-field test of the second type of work equipment A first stress detecting means for detecting
Second stress detecting means for detecting the actual work stress of each part of the working machine when the actual work is performed by the working machine of
A correction coefficient is calculated based on the third stress detection means for detecting the standard stress of each part of the work equipment by the field test of the first type work equipment, and the detection results by the first stress detection means and the second stress detection means. On the basis of the calculated stress after correction, the coefficient calculation means for calculating, the storage means for storing the correction coefficient, the calculation means for calculating the corrected stress by correcting the detection result by the third stress detection means with the correction coefficient, The above-described object is achieved by including an evaluation unit that calculates the strength evaluation of the working machine. 4. The strength evaluation device for a working machine according to the invention of claim 4 is
The first storage means for detecting and storing in advance the standard stress of each part of the working machine when performing the standard work according to the standard operation pattern, and for detecting the actual working stress of each part of the working machine when performing the actual work in advance. A second storage means for storing, a coefficient calculating means for calculating a correction coefficient based on the standard stress and the actual work stress, a third storage means for storing the correction coefficient, and a standard work with a standard operation pattern were performed. By including the calculating means for calculating the corrected stress by correcting the standard stress of each part of the working machine with the correction coefficient, and the evaluating means for calculating the strength evaluation of the working machine based on the calculated corrected stress as described above. Achieve the purpose. 5, The program according to the invention of claim 5 is a correction calculated based on the standard stress of each part of the working machine when performing the standard work according to the standard operation pattern and the actual work stress of each part of the working machine when performing the actual work. Procedure to correct the standard stress of each part of the working machine when performing standard work according to the standard operation pattern based on the coefficient, and procedure to calculate the strength evaluation of the working machine based on the corrected stress corrected by the correction procedure The above-described object is achieved by using and as a program for executing strength evaluation by a computer.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a strength evaluation method for a working machine according to the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view of a hydraulic excavator 10 to which a strength evaluation method according to an embodiment of the present invention is applied, and FIG. 2 is a block diagram showing a system configuration of a field test according to the present embodiment. As shown in FIG. 1, a hydraulic excavator 10 includes a traveling structure 1, a revolving structure 2 rotatably mounted on the traveling structure 1, a boom 3A, an arm 3B rotatably attached to the revolving structure 2. And a front device 3 including a bucket 3C. The boom 3A is a boom cylinder 3a.
The arm 3B is rotated by the expansion and contraction of the arm cylinder 3b.
The bucket 3C is rotated by the expansion and contraction of the bucket cylinder 3c. The front device 3 is provided with a stress detector 4 (see FIG. 2) such as a strain gauge for detecting the stress σ1 at each front portion.

Generally, hydraulic excavators are classified into large, medium and small types according to vehicle weight. In the present embodiment, for example, the strength evaluation of a medium-sized hydraulic excavator 10 of a new model is performed. In this case, the hydraulic excavator 20 of the same class (medium size) as the hydraulic excavator 10 is preliminarily tested in the field, and the hydraulic excavator 30 of almost the same model as the hydraulic excavator 20 is used.
Is tested in the field to obtain the correction coefficient α. Then, the stress σ1 of each front portion detected by the in-field test of the hydraulic excavator 10 is corrected by a correction coefficient α as described later, and the strength of the front device 3 is evaluated based on the stress correction value σA. The on-site test is to drive the working machine in the factory according to a predetermined standard operation pattern, and check whether the working machine is operating normally from the measured data such as stress, oil pressure and oil temperature at that time. This is a test to confirm.

As shown in FIG. 2, the strength evaluation system is
A stress detector 4, a storage device 5 such as a hard disk, and C
It has an arithmetic unit 6 including a PU, a ROM, a RAM and the like, and an output unit 7 such as a monitor and a plotter. The signals from the stress detector 4 and the storage device 5 are input to the arithmetic unit 6. The computer 6 stores various programs and a fatigue life evaluation diagram (SN diagram) of the front device 3. The correction coefficient α is stored in the storage device 5, the stress detection value σ1 is corrected by the correction coefficient α by the processing in the arithmetic device 6, and the corrected stress σA is applied to the SN diagram to reduce the fatigue life. Presumed. This estimated life is output to the output device 7 together with the stress σA.

The method of calculating the correction coefficient α will be described below. FIG. 3 is a block diagram showing a method of calculating the correction coefficient α. To calculate the correction coefficient α, first, the hydraulic excavator 20 in the same class (medium size) as the hydraulic excavator 10 is tested in a factory (in-site test). Like the hydraulic excavator 10, the front device 3 of the hydraulic excavator 20 is provided with a stress detector 4 for detecting the stress σ1 of each front portion. The signal from the stress detector 4 and the operation pattern at that time are stored in the in-field test storage unit 40a of the coefficient calculation unit 40. When the hydraulic excavator 10 and the hydraulic excavator 20 are of almost the same model, the hydraulic excavator 10 is tested in the field instead of being tested in the field to calculate the correction coefficient α, and the hydraulic shovel 10 is used by using the correction coefficient α. May be evaluated.

Next, a hydraulic excavator 30 of almost the same type as the hydraulic excavator 20 is subjected to a test operation (field test) at the work site. The cylinders 3a to 3c of the front device 3 of the hydraulic excavator 30 include a stroke sensor 31 for detecting the cylinder stroke S and a pressure P for detecting the pressure P (rod chamber pressure and bottom chamber pressure) of the cylinders 3a to 3c. A sensor 32 is provided. These sensors 3
The signals from 1, 32 are stored in the field test storage unit 40b of the coefficient calculation unit 40. The field test may be performed using the hydraulic excavator 20 instead of the hydraulic excavator 30.
That is, the same hydraulic excavator 20 may perform the on-site test and the on-site test, respectively.

The coefficient calculation unit 40 executes a predetermined program to calculate the correction coefficient α and stores it in the storage unit 50. FIG. 4 is a flowchart showing an example of processing executed by the coefficient calculation unit 40. In step S1, the signals from the stroke sensor 31 and the pressure sensor 32 stored in the field test storage unit 40b are fetched. Then, step S2
Then, the posture change of the front device 3, that is, the operation of the hydraulic excavator 30 is analyzed based on the detection value S from the stroke sensor 31. In step S3, the stress 2 at each front portion is calculated based on the detected value P from the pressure sensor 32.
The processes of steps S2 and S3 are performed as follows.

FIG. 5 is an example of modeling the front device 3 with beam elements. In order to perform the motion analysis, first, the initial coordinates (X, Y) of the node data that configure the beam element and the initial strokes of the cylinders 3a to 3c are determined. The stroke amount S of the cylinders 3a to 3c from this initial state is S.
The length of the beam element (3a to 3c in the figure) corresponding to the cylinders 3a to 3c is changed according to the above, and the posture change of the front device 3 is detected. An operation pattern (excavation, turning, etc.) corresponding to the posture change of the front device 3 is stored in the coefficient calculation unit 40 in advance, and it is determined by which pattern the front device 3 has changed the posture. That is, the operation of the hydraulic excavator 30 is analyzed.

In order to calculate the stress σ of each front portion in the field test, the posture of the front device 3 is changed according to the cylinder stroke S as described above, and in that state, the pressure sensor 32 is applied to the nodes of the beam elements 3a to 3c. A load corresponding to the detected value P of is applied. With this, the pin load acting on each node is calculated, and the sectional stress σ acting on the beam element is calculated using this pin load. It should be noted that, instead of calculating the stress σ from the cylinder stroke S and the cylinder pressure P, the stress detector 4 is provided in each part of the front similarly to the in-field test, and the stress σ of the field test is directly detected by the stress detector 4. You may An example of the operation analysis result and stress calculation result of the field test is shown in FIG. The stresses A1 to A4 in the figure are the maximum stress σ (peak stress) under each operation.
Is.

In step S4, the signal from the stress detector 4 and the operation pattern at that time stored in the on-site test storage unit 40a are fetched. In this case, the on-site test of the hydraulic excavator 20 is performed according to the operation pattern as shown in FIG. 6B, for example. The maximum stress σ1 under each operation is B1 to B4
Indicate.

In step S5, the correction coefficient α is calculated by taking the ratio of the stress σ2 calculated by the field test and the stress σ1 detected by the field test. In this case, those having the same operation pattern, that is, stresses A1 and B1, A2 and B2, A
Take the ratio of 3 and B3, A4 and B4 respectively (A1 / B1, A2 /
B2, A3 / B3, A4 / B4) The correction coefficient α is calculated for each operation pattern. Then, the correction coefficient α is stored in the storage unit 50, and the process ends. For convenience of description, the storage device 5
Although the storage unit 50 is provided separately from the storage unit 5,
You may make it serve as 0.

The strength evaluation of the front device 3 of the hydraulic excavator 10 is performed as follows. First, as described above, the on-site test of the hydraulic excavator 20 and the on-site test of the hydraulic excavator 30 are performed, and the correction coefficient α corresponding to the operation pattern is obtained and stored in the storage unit 50. Next, the correction coefficient α is stored in the storage device 5, the field test of the hydraulic excavator 10 is performed according to a predetermined operation pattern, and the stress σ1 of each front part is detected by the stress detector 4. The arithmetic unit 6 reads the correction coefficient α corresponding to this operation from the storage unit 5, and uses the detected stress value σ as the correction coefficient α.
Multiply by 1 to calculate the stress σA (= α × σ1), and output device 7
Output to. Further, in the computing device 6, the corrected stress σ is added to the fatigue life evaluation diagram (SN diagram) of the front device 3 stored in advance.
A is applied to estimate the life during actual operation and output to the output device 7. Thereby, the strength of the front device 3 is evaluated. Alternatively, the stress allowable value may be stored in advance in the computing device 6, and the strength of the front device 3 may be evaluated based on whether the corrected stress σA is less than or equal to this allowable value.

As described above, in this embodiment, the correction coefficient α for estimating the stress detection value σ2 from the stress detection value σ1 by comparing the stress detection value σ1 by the in-field test and the stress detection value σ2 by the field test. Then, the stress detection value σ1 is corrected by the correction coefficient α. As a result, once the correction coefficient α is obtained, the strength of the front device 3 can be accurately evaluated by the field test thereafter without performing the field test. Further, since the operation pattern of the front device 3 is analyzed and the correction coefficient α is set according to the operation pattern, the accuracy of stress correction is further improved.

In the above-described embodiment, the front device 3 of the hydraulic excavator is applied to the front device 3, especially the backhoe front, but it may be applied to the loader front. Further, it may be applied to other structural parts than the front device 3. Further, it may be applied to other working machines other than the hydraulic excavator.

In the correspondence between the above embodiment and the claims, the hydraulic excavator 10 is provided with the first type working machine, and the hydraulic excavators 20, 30 are provided with the second type working machine in the hydraulic excavator 20. The stroke detector 3 provided in the hydraulic excavator 30 has a first stress detector 4 as the first stress detector.
1 and the pressure sensor 32 are the second stress detecting means, the stress detector 4 provided in the hydraulic excavator 10 is the third stress detecting means, the coefficient calculating section 40 is the coefficient calculating means, and the storage device 5 is the storing means. The computing device 6 serves as the calculating means, and the computing device 6
Indicates the evaluation means, the on-site test storage section 40a constitutes the first storage means, the on-site test storage section 40b constitutes the second storage means, and the storage section 50 constitutes the third storage means.

[0020]

As described above in detail, according to the present invention, the correction coefficient is calculated based on the standard stress obtained by the field test and the actual work stress obtained by the field test. The standard stress detection value by the test was corrected. Accordingly, once the correction coefficient is obtained, the strength of the structure can be accurately evaluated by the field test thereafter without performing the field test, and the optimum shape design can be performed.

[Brief description of drawings]

FIG. 1 is a perspective view of a hydraulic excavator to which a strength evaluation method according to an embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a system configuration of an in-field test by the strength evaluation method according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a method of calculating a correction coefficient used in the strength evaluation method according to the embodiment of the present invention.

FIG. 4 is a flowchart showing an example of processing executed by a coefficient calculation unit in FIG.

FIG. 5 is a diagram showing an example of modeling a front device with beam elements.

FIG. 6 is a diagram showing an example of operation patterns of a field test and a field test.

[Explanation of symbols]

3 Front device 3A Boom 3B Arm 3C Bucket 3a, 3b, 3c Cylinder 4 Stress detector 5 Memory device 6 Computing device 7 Output device 10,20,30 Hydraulic excavator 31 Stroke sensor 32 Pressure sensor 40 Count calculation unit 40a Field test storage unit 40b Field test memory

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshihiro Ohno             Hitachi Construction Machinery Co., Ltd.             Ceremony Company Tsuchiura Factory F-term (reference) 2G024 AD17 BA13 CA11 DA01 DA05                       DA06 EA20 FA02 FA06

Claims (5)

[Claims] 1. A strength evaluation method for a working machine, wherein the strength of the working machine of the first type is evaluated based on the test results of the working machine of the first type and the working machine of the second type. The standard stress of each part of the working machine is detected by the field test of the second type working machine according to the standard operation pattern, and (2) the work when the actual work is performed on site by the second working machine. The actual work stress of each part of the machine is detected, (3) the correction coefficient is calculated and stored based on the standard stress and the actual work stress, and (4) the work of the first type according to the standard operation pattern. The standard stress of each part of the working machine is detected by an in-field test of the machine, and (5) this stress detection value is corrected by the correction coefficient, and the strength of the first type working machine is evaluated based on the corrected stress. A method for evaluating the strength of a working machine. 2. The strength evaluation method for a working machine according to claim 1, wherein (1) an operation when actual work is performed on site by the second type working machine is analyzed, and (2) the second The strength of the working machine characterized in that the detection result of the standard stress and the detection result of the actual working stress of the two types of working machines are compared under the same motion, and the correction coefficient is set for each motion. Evaluation methods. 3. A first type working machine for performing an in-field test according to a standard operation pattern, and a second type working machine for respectively performing an on-site test according to a standard operation pattern and an actual work on site. First stress detecting means for detecting a standard stress of each part of the working machine by an in-field test of the second type working machine, and each part of the working machine when an actual work is performed on site by the second type working machine. Second stress detecting means for detecting the actual work stress of the first working machine, a third stress detecting means for detecting a standard stress of each part of the working machine by an in-field test of the first type working machine, and the first stress detecting means. Means and a coefficient calculation means for calculating a correction coefficient based on the detection result by the second stress detection means, a storage means for storing the correction coefficient, and a detection result by the third stress detection means by the correction coefficient. After correction After correction Working machine strength evaluation system, characterized in that it comprises a calculation unit, on the basis of the calculated corrected stress, and evaluating means for calculating the strength evaluation of the working machine for calculating the force. 4. A first storage means for previously detecting and storing a standard stress of each part of the working machine when performing a standard work according to a standard operation pattern, and an actual working stress of each part of the working machine when performing an actual work. A second storage means for detecting and storing in advance, a coefficient calculation means for calculating a correction coefficient based on the standard stress and the actual work stress, a third storage means for storing the correction coefficient, and a standard Calculating means for calculating the corrected stress by correcting the standard stress of each part of the working machine when performing the standard work according to the operation pattern with the correction coefficient, and the strength evaluation of the working machine based on the calculated corrected stress. A strength evaluation device for a working machine, comprising: an evaluation means for calculating. 5. A standard based on a correction coefficient calculated based on the standard stress of each part of the working machine when performing standard work according to the standard operation pattern and the actual work stress of each part of the working machine when performing actual work. Based on the procedure for correcting the standard stress of each part of the working machine when performing standard work according to the operation pattern, and the corrected stress corrected by the correction procedure,
A program for executing the procedure for calculating the strength evaluation of the working machine and the strength evaluation by the computer.