Stress estimation device

Abstract

The invention provides a stress estimation device capable of estimating stress acting on a dump truck with higher precision. A stress estimation device (100) is provided with a storage unit (110) and a calculation unit (120), and estimates stress acting on a dump truck (200). A storage unit (110) stores a force calculation formula (111) and a stress calculation formula (112). The calculation unit (120) has a force calculation unit (121) and a stress calculation unit (122). The force calculation unit (121) calculates a force acting on a predetermined portion of the dump truck (200) using the output value of the force sensor (230) or the output value of the acceleration sensor (240) and the output value of the force sensor (230), and a force calculation formula (111) stored in the storage unit (110). The stress calculation unit (122) calculates the stress acting on the dump truck (200) using the force calculated by the force calculation unit (121) and the stress calculation formula (112) stored in the storage unit (110).

Description

Technical Field

[0001] The present invention relates to a stress estimating device. Background Art

[0002] A stress calculation system for a dump truck is known in the past. For example, the stress calculation system for a dump truck described in the following patent document 1 has a storage mechanism, a detection mechanism, and a calculation mechanism (abstract, paragraph 0008, and technical solution 1). The storage mechanism stores data on stresses generated at a predetermined position of the dump truck when multiple external forces act on the dump truck. The detection mechanism detects the direction and magnitude of the external force acting on the dump truck.

[0003] The calculation means estimates the time variation of stress generated at the predetermined position by interpolation or extrapolation based on the detection value of the detection means and the stress data stored in the storage means. According to the conventional stress calculation system, when calculating the time variation of stress at the vehicle evaluation position, a process of converting from the frequency domain to the time domain is not included, so the time variation of stress at the vehicle evaluation position can be calculated with high accuracy (Patent Document 1, Abstract, Paragraph 0009).

[0004] In addition, the stress calculation system of the working machine described in the following patent document 2 includes a load-related parameter detector, a posture-related parameter detector and a calculation unit (Abstract, paragraph 0009, technical solution 1). The load-related parameter detector detects a parameter representing a change in the working machine when a load acts from the outside, that is, a load-related parameter. The posture-related parameter detector detects a parameter representing the posture of the working machine, that is, a posture-related parameter.

[0005] The computing unit estimates the stress distribution of the working machine at the time of the output value based on the output value of the load-related parameter detector and the posture-related parameter detector. According to this conventional stress computing system, stress evaluation at a desired position of the working machine can be performed by a small number of sensors, thereby maintaining the motion performance of the working machine and suppressing the cost (Patent Document 2, Abstract, Paragraph 0010).

[0006] In addition, the fatigue management system described in the following patent document 3 has a stress calculation unit, a damage degree calculation unit and an index value calculation unit (Abstract, paragraph 0010, technical solution 1). The stress calculation unit calculates the stress acting on multiple parts of the engineering machine based on the output of the sensor installed on the engineering machine. The damage degree calculation unit calculates the cumulative damage degree of each of the parts based on the stress.

[0007] The index value calculation unit calculates a fatigue index value weighted by the cumulative damage degree for each of the parts. In this way, a fatigue management system can be provided that can manage fatigue of each part of the construction machinery more accurately than before by using fatigue index values ​​(Patent Document 3, paragraph 0011).

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2013-164396

[0011] Patent Document 2: International Publication No. 2013 / 172277

[0012] Patent Document 3: International Publication No. 2021 / 064776 Summary of the invention

[0013] In the stress calculation system of the above-mentioned Patent Document 1, for example, the time variation of the stress at the vehicle evaluation position is obtained by interpolation approximation or extrapolation approximation based on the external force detected by the above-mentioned detection mechanism and the stress data stored in the above-mentioned storage mechanism. In addition, in the stress calculation system of the working machine of the above-mentioned Patent Document 2, based on the output values ​​of the pressure detector, the acceleration detector, the displacement detector and the rotation angle detector, the stress distribution of the working machine at the time of the output value is estimated.

[0014] Similarly, in the fatigue management system of Patent Document 3, stresses acting on multiple parts of the construction machine are calculated based on the output of sensors installed on the construction machine. However, in order to estimate the stress acting on the dump truck with higher accuracy, the method of directly estimating the stress from the output value of the sensor has its limits, and the above-mentioned conventional system still has room for improvement.

[0015] The present invention provides a stress estimating device capable of estimating stress acting on a dump truck with higher accuracy.

[0016] One embodiment of the present invention is a stress estimating device having a storage unit and a calculation unit, which estimates stress acting on a dump truck. The stress estimating device is characterized in that the storage unit stores a force calculation formula and a stress calculation formula, wherein the force calculation formula is used to calculate the force acting on a specified part of the dump truck based on the output value of a force sensor that detects the force acting on a suspension device of the dump truck, or the output value of an acceleration sensor installed on the dump truck and the output value of the force sensor, and the stress calculation formula is used to calculate the stress acting on the dump truck based on the force, and the calculation unit has: a force calculation unit, which uses the output value of the force sensor or the output values ​​of the acceleration sensor and the force sensor, and the force calculation formula stored in the storage unit to calculate the force; and a stress calculation unit, which uses the force calculated by the force calculation unit and the stress calculation formula stored in the storage unit to calculate the stress acting on the dump truck.

[0017] Effects of the Invention

[0018] According to the above aspect of the present invention, it is possible to provide a stress estimating device capable of estimating stress acting on a dump truck with higher accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a block diagram showing one embodiment of the stress estimating device of the present invention.

[0020] Figure 2 Yes means Figure 1 A side view of an example of a dump truck used as a target of the stress estimating device.

[0021] Figure 3 Yes means including Figure 1 A block diagram of an example of a fatigue management system of a stress estimation device.

[0022] Figure 4 Yes Figure 2 Schematic diagram of an example of forces acting on a specified part of a dump truck.

[0023] Figure 5 Yes Figure 2 Schematic diagram of an example of forces acting on a specified part of a dump truck.

[0024] Figure 6 Yes means Figure 1 A block diagram of a modified example of the stress estimating device. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the stress estimating device according to the present invention will be described with reference to the drawings. Figure 1 This is a block diagram showing one embodiment of the stress estimating device of the present invention. Figure 2 Yes means Figure 1 1 is a side view of an example of a dump truck 200 as a target of the stress estimating device 100. Figure 3 Yes means including Figure 1 FIG. 1 is a block diagram of an example of a fatigue management system 300 of the stress estimating apparatus 100 .

[0026] like Figure 1 As shown, the stress estimation device 100 of this embodiment includes a storage unit 110 and a computing unit 120. Figure 2 The stress acting on the dump truck 200 shown in FIG. Figure 3 The server 310 and the information terminal 320 shown together constitute a part of the fatigue management system 300 for managing fatigue of the parts of the dump truck 200 .

[0027] Hereinafter, the structure of the dump truck 200 to which the stress estimation device 100 of this embodiment is applied will be briefly described first, and then the structures of the stress estimation device 100 and the fatigue management system 300 of this embodiment will be described in detail. The dump truck 200 is a large transport vehicle that transports goods such as ore mined in a mine.

[0028] like Figure 2 As shown, the dump truck 200 has, for example, a frame 210; left and right front wheels 201; left and right rear wheels 202; left and right suspension devices 203 on the front wheel side, each consisting of a hydraulic cylinder; left and right suspension devices 204 on the rear wheel side, each consisting of a hydraulic cylinder; a cargo box or a vehicle body 205; left and right lifting cylinders 206; a travel drive device 220; a structure 207; and a cabin 208. In addition, as Figure 1 As shown, the dump truck 200 has, for example, a force sensor 230, an acceleration sensor 240, a controller 250, an output device 260, and a communication device 270. In addition, Figure 1 Although the force sensor 230 and the acceleration sensor 240 are described in the specification, the dump truck 200 does not need to include both of them and only needs to include the force sensor 230 , and does not need to include the acceleration sensor 240 .

[0029] Figure 2 Although not shown in the figure, the force sensor 230 can be a hydraulic sensor that detects the pressure of the hydraulic cylinder of each suspension device 203, 204. In addition, the force sensor 230 that detects the force acting on each suspension device 203, 204 may be, for example, a load sensor. Figure 1 In the figure, a single force sensor 230 is shown to represent a plurality of force sensors 230. The details will be described later. Figure 1As shown, the force sensor 230 outputs a hydraulic pressure detection value of a hydraulic cylinder constituting each of the suspension devices 203 and 204 , that is, a force detection value HV to the controller 250 .

[0030] The vehicle frame 210 is a ladder-shaped frame structure, for example. The front wheel suspension device 203 is installed on the left and right sides of the front part of the vehicle frame 210, and the rear wheel suspension device 204 is installed on the left and right sides of the rear part of the vehicle frame 210. In addition, the vehicle frame 210 supports the vehicle body 205 on which the cargo of the dump truck 200 is loaded from below. Figure 2 Although not shown in the figure, when the dump truck 200 has an acceleration sensor 240, for example, an acceleration sensor 240 for detecting the acceleration of the dump truck 200 is mounted on the vehicle frame 210 (see Figure 1 ).

[0031] In addition, the acceleration sensor 240 may also be installed on the vehicle body 205 for loading cargo. Figure 1 As shown, the acceleration sensor 240 outputs the acceleration detection value AV of the dump truck 200 to the controller 250. The acceleration detected by the acceleration sensor 240 mounted on the vehicle body 205 is proportional to the inertial force acting on the vehicle body 205 when the dump truck 200 is traveling. Therefore, the acceleration sensor 240 also functions as an inertial force sensor that detects the inertial force acting on the vehicle frame 210.

[0032] The test dump truck 200A has the same configuration as the dump truck 200 used as the target of the stress estimation device 100 of the present embodiment, and is used to determine the force calculation formula 111 described later. Figure 1 As shown by the two-dot chain line in FIG. 2 , the test dump truck 200A further includes a test force sensor 280. The test force sensor 280 is mounted on a predetermined portion of the test dump truck 200A corresponding to a predetermined portion on which a force acts in the dump truck 200, and detects the force acting on the predetermined portion of the test dump truck 200A. More specifically, the predetermined portion of the dump truck 200 is a portion corresponding to an input position of the force with respect to the analytical model of the dump truck 200 in the structural analysis for calculating the stress acting on the dump truck 200.

[0033] Figure 4 as well as Figure 5 Yes Figure 2 Schematic diagram of an example of force F acting on a predetermined part of the dump truck 200. Figure 4 as well as Figure 5In the example shown, the prescribed portion of the dump truck 200 includes a plurality of portions 211 of the frame 210 of the dump truck 200 that supports the vehicle body 205 to which the suspension devices 203 and 204 are mounted and on which the cargo of the dump truck 200 is loaded. In addition, the prescribed portion of the dump truck 200 includes a mounting member 214 of the frame 210 to which a force is applied from a bracket 222 provided in front of an axle box 221. More specifically, the prescribed portion of the dump truck 200 includes, for example, a plurality of portions 211 of the frame 210 that are in contact with the bottom of the vehicle body 205 and a mounting member 214 of the frame 210 that supports the axle box 221.

[0034] Figure 4 In the example shown, the force F acting on a specified portion of the dump truck 200 includes a load L acting from the vehicle body 205 to multiple portions 211 of the frame 210 due to the gravity acting on the vehicle body 205 loaded with cargo, and a load L acting from the axle box 221 to the mounting component 214 of the frame 210. Figure 5 In the example shown, the force F acting on the predetermined portion of the dump truck 200 includes a force F acting from the vehicle body 205 to the plurality of portions 211 of the frame 210 due to the inertial force acting on the vehicle body 205 loaded with cargo, and a force F acting from the axle box 221 to the mounting member 214 of the frame 210. For example, when the dump truck 200 accelerates or decelerates or turns, gravity and inertial force or centrifugal force simultaneously act on the vehicle body 205 loaded with cargo, and thus, a composite force such as Figure 4 as well as Figure 5 The force F is shown.

[0035] like Figure 2 As shown, the left and right front wheels 201 are steering wheels rotatably supported at the front of the vehicle frame 210 via the left and right suspension devices 203. The left and right rear wheels 202 are driving wheels rotatably supported at the rear of the vehicle frame 210 via the left and right suspension devices 204. The left and right suspension devices 203 on the front wheel side elastically support the left and right front wheels 201, and the left and right suspension devices 204 on the rear wheel side elastically support the left and right rear wheels 202 via the axle box 221 of the travel drive device 220.

[0036] The vehicle body 205 is connected to the left and right brackets 212 of the vehicle frame 210 via the connecting pin 213 at the rear part of the bottom, and the upper end of the lifting cylinder 206 is rotatably connected to the front part of the bottom. The lower end of the lifting cylinder 206 is rotatably connected to the vehicle frame 210. The lifting cylinder 206 is composed of, for example, a hydraulic cylinder. When the lifting cylinder 206 is extended, the vehicle body 205 tilts on the vehicle frame 210 with the connecting pin 213 as the rotation center, so that the cargo loaded on the vehicle body 205 is dropped.

[0037] The travel drive device 220 is connected to the left and right rear wheels 202 to drive them to rotate. The travel drive device 220 includes, for example, an axle box 221 and a bracket 222. The axle box 221, for example, accommodates a travel motor and a reduction device (not shown) and is configured to be cylindrical and extend to the left and right. The bracket 222, for example, is configured to protrude forward from the axle box 221. The front end of the bracket 222 is rotatably mounted relative to the mounting member 214 of the vehicle frame 210.

[0038] The structure 207 defines a machine room at the front of the vehicle frame 210. The structure 207 contains an engine, a hydraulic pump, etc. (not shown). The cabin 208 is provided on a flat bottom surface located at the upper part of the structure 207. The cabin 208 is box-shaped and defines a cab for the operator. Although not shown, a driver's seat, a steering wheel, operating pedals, etc., for the operator to sit on are provided in the cabin 208.

[0039] The controller 250 is constituted by, for example, one or more microcontrollers having a central processing unit (CPU), a memory, a timer, and an input / output unit, and is housed in the chamber 208. Although described in detail later, in the present embodiment, the stress estimation device 100 is constituted by, for example, the controller 250 of the dump truck 200, and has a storage unit 110 and a computing unit 120. The storage unit 110 and the computing unit 120 represent the functions of the stress estimation device 100 realized by, for example, the CPU executing a program stored in a memory of the controller 250 constituting the stress estimation device 100.

[0040] The output device 260 is composed of, for example, a display device and a speaker, and is housed in the cabin 208 and connected to the controller 250. The output device 260 displays the information output from the stress estimation device 100 on a screen or outputs it by voice, for example, thereby notifying the operator in the cabin 208 of the information output from the stress estimation device 100. The communication device 270 is mounted on the dump truck 200 and connected to the controller 250, and includes at least one of a wireless communication device that communicates with the outside via a wireless communication line and a satellite communication device that communicates with the outside via a satellite communication line.

[0041] Next, the configurations of the stress estimation device 100 and the fatigue management system 300 according to this embodiment will be described in detail. Figure 1 As shown, the stress estimation device 100 of the present embodiment includes a storage unit 110 and a computing unit 120, and estimates the stress S acting on the dump truck 200. As described above, the storage unit 110 and the computing unit 120 represent the functions of the stress estimation device 100 realized by, for example, the CPU executing a program stored in a memory of the controller 250 of the dump truck 200.

[0042] The storage unit 110 stores, for example, a force calculation formula 111 and a stress calculation formula 112. Figure 1 In the example shown, the storage unit 110 stores an S-N curve 113 of the target component of the dump truck 200 and a cumulative damage degree 114 of the target component calculated by the calculation unit 120. The force calculation formula 111 is a formula for calculating the force F acting on a predetermined portion of the dump truck 200 based on the output value of the force sensor 230 that detects the hydraulic pressure of the hydraulic cylinder constituting the suspension device 203, 204 of the dump truck 200, or the output value of the acceleration sensor 240 and the force sensor 230 installed in the dump truck 200. As examples of the force calculation formula 111, the following formulas (1) to (3) are shown.

[0043]

Formula 1

[0044]

[0045] In the force calculation equation 111 shown in the above equations (1) to (3), f1, f2, ... are the forces F acting on the predetermined parts of the dump truck 200, s1, s2, ... are the output values ​​of the force sensor 230 or the acceleration sensor 240, and at least one includes the output value of the force sensor 230. In addition, s1', s2', ... are the output values ​​of the force sensor 230 or the acceleration sensor 240, and are the first-order differential values ​​of s1, s2, ..., s1", s2", ... are the output values ​​of the force sensor 230 or the acceleration sensor 240, and are the second-order differential values ​​of s1, s2, .... In addition, K, L1 to L3, M1 to M3, and A are constants determined based on the characteristics of the input force F.

[0046] In addition, s1, s2, ... may all be output values ​​of the force sensor 230. As long as at least one includes the output value of the force sensor 230, the others may all be output values ​​of the acceleration sensor 240. The output values ​​of the force sensor 230 and the output values ​​of the acceleration sensor 240 may be mixed.

[0047] The force calculation formula 111 can be determined, for example, as follows. The test dump truck 200A has Figure 1 as well as Figure 2 The same structure as the conventional dump truck 200 shown in FIG. Figure 1The test dump truck 200A is driven for a predetermined period of time under various conditions including the presence or absence of cargo and the presence or absence of a slope, using the test force sensor 280 indicated by the double-dashed line. Then, the force detection value FV, which is the output value of the test force sensor 280 of the test dump truck 200A, the force detection value HV, which is the output value of the force sensor 230, and the acceleration detection value AV, which is the output value of the acceleration sensor 240, are obtained. Then, the relationship between the output values ​​of each sensor obtained is analyzed using, for example, a multiple regression equation and a regression equation obtained by machine learning, thereby determining the force calculation equation 111.

[0048] That is, the force calculation formula 111 is determined based on, for example, the output value of the test force sensor 280 of the test dump truck 200A and the output value of the force sensor 230 of the test dump truck 200A, or based on the output value of the test force sensor 280 of the test dump truck 200A and the output values ​​of the force sensor 230 and the acceleration sensor 240 of the test dump truck 200A. In addition, the test force sensor 280 is not mounted on, for example, a normal dump truck 200 as a target of the stress estimation apparatus 100, but is mounted on a predetermined portion of the test dump truck 200A having the same configuration as the normal dump truck 200, and detects the force F acting on the predetermined portion of the test dump truck 200A corresponding to the predetermined portion of the normal dump truck 200.

[0049] In addition, the force calculation formula 111 can also be determined based on, for example, an analytical model of the dump truck 200. Specifically, conditions such as the speed, acceleration, and angular velocity of the dump truck 200 are input to the analytical model of the dump truck 200. Then, from the analytical model, the force F acting on a predetermined part of the dump truck 200 due to the gravity and inertial force acting on each part of the dump truck 200, the output value of the force sensor 230, i.e., the force detection value HV, or the force F acting on the predetermined part, the output value of the force sensor 230, i.e., the force detection value HV, and the output value of the acceleration sensor 240, i.e., the acceleration detection value AV, are calculated. Then, for example, the relationship between the calculated force F acting on the predetermined part of the dump truck 200 and the force detection value HV, or the relationship between the force F acting on the predetermined part, the force detection value HV, and the acceleration detection value AV is analyzed using a multiple regression formula or a regression formula obtained by machine learning, thereby determining the force calculation formula 111.

[0050] On the other hand, the stress calculation formula 112 is a formula for calculating the stress S acting on the dump truck 200 based on the force F calculated using the above-mentioned force calculation formula 111, that is, based on the force F acting on a predetermined portion of the dump truck 200. As examples of the stress calculation formula 112, the following formulas (4) to (6) are shown.

[0051]

Formula 2

[0052]

[0053] In the stress calculation formula 112 shown in the above-mentioned formulas (4) to (6), σ1, σ2, ... are stresses S acting on the dump truck 200, for example, stresses S acting on each component constituting the frame 210. In addition, s1, s2, ... are output values ​​of the force sensor 230 or the acceleration sensor 240, s1', s2', ... are first-order differential values ​​of these output values, and s1", s2", ... are second-order differential values ​​of these output values. In addition, f1, f2, ... are forces F acting on each specified part of the dump truck 200 calculated using the force calculation formula 111, f1', f2', ... are first-order differential values ​​of these forces F, and f1", f2", ... are second-order differential values ​​of these forces F. In addition, K s , K f , L s1 To L s3 , L f1 To L f3 、M s1 To M s3 、M f1 To M f3 , and A are constants determined based on the characteristics of the input force F.

[0054] In addition, when calculating the stress S in the above-mentioned equations (4) to (6), the force F calculated by the force calculation equation 111 is necessary, but for s1, s2, ..., any one of the output values ​​of the force sensor 230 or the acceleration sensor 240 can be used.

[0055] As described above, the specified portion of the dump truck 200 is, for example, a portion corresponding to the input position of the force F in the structural analysis for calculating the stress S acting on the dump truck 200 relative to the analytical model of the dump truck 200. The stress calculation formula 112 shown in (4) to (6) above is derived, for example, from the analytical model. That is, the stress calculation formula 112 can be determined, for example, as described below. Forces F of various magnitudes and directions are input to the input position of the force F in the analytical model of the dump truck 200, and the stress S acting on each part of the dump truck 200 is calculated by the analytical model. Then, the relationship between the input force F and the calculated stress S is obtained using a multiple regression formula and a regression formula based on machine learning, thereby determining the stress calculation formula 112 shown in (4) to (6) above.

[0056] In addition, the S-N curve 113 of the parts of the dump truck 200 stored in the storage unit 110 is a curve that shows the relationship between the time-history waveform of the stress S acting on the parts of the dump truck 200 and the number of cycles of the stress amplitude. The S-N curve 113 is used to calculate the cumulative damage degree D by the damage degree calculation unit 123 of the calculation unit 120. In the storage unit 110, for example, the S-N curve 113 of each part of the dump truck 200 that needs to manage fatigue based on the cumulative damage degree D is stored.

[0057] like Figure 1 As shown, the operation unit 120 includes a force operation unit 121 and a stress operation unit 122. In addition, the operation unit 120 may also include, for example, a damage degree operation unit 123. Each part of the operation unit 120, for example, expresses each function of the stress estimation device 100 implemented by the CPU executing the program stored in the memory as described above. In addition, each part of the operation unit 120 may be, for example, composed of one device, or may be composed of two or more devices.

[0058] The force calculation unit 121 calculates the force F acting on a predetermined portion of the dump truck 200 using the output value of the force sensor 230 or the output values ​​of the force sensor 230 and the acceleration sensor 240 and the force calculation formula 111 stored in the storage unit 110. The stress calculation unit 122 calculates the stress S acting on the dump truck 200 using the force F calculated by the force calculation unit 121 and the stress calculation formula 112 stored in the storage unit 110. The damage degree calculation unit 123 calculates the cumulative damage degree D of the parts of the dump truck 200 using the stress S calculated by the stress calculation unit 122 and the S-N curve 113 stored in the storage unit 110.

[0059] More specifically, the damage degree calculation unit 123 performs frequency analysis of the time-history stress waveform based on, for example, the "range pair" method, the peak valley method, or the rain flow counting method. Then, the damage degree calculation unit 123 calculates the cumulative damage degree D based on, for example, the Miner's law and the modified Miner's law shown in the following formula (7). In formula (7), D is the cumulative damage degree, n is i is the number of loads of stress S, N i is the fatigue life obtained from the S-N curve 113 .

[0060]

Formula 3

[0061]

[0062] The cumulative damage degree D of each component of the dump truck 200 calculated by the damage degree calculation unit 123 is stored in, for example, the storage unit 110. In addition, the cumulative damage degree D of each component of the dump truck 200 is transmitted to the outside through a satellite communication line or a wireless communication line by the communication device 270, for example, together with the identification information and position information of each dump truck 200. In addition, the cumulative damage degree D of each component of the dump truck 200 is notified to the operator of the dump truck 200 by the output device 260.

[0063] like Figure 3 As shown, the fatigue management system 300 of the present embodiment includes, for example, the stress estimation device 100 mounted on the dump truck 200, and a server 310. In addition, the fatigue management system 300 may include, for example, an information terminal 320. The server 310 receives the cumulative damage degree D transmitted from the communication devices 270 of the plurality of dump trucks 200 via a wireless communication line or a satellite communication line, for example, via a wireless communication base station WB or a communication satellite CS and a satellite communication base station SB, and a network such as the Internet.

[0064] The server 310 stores the cumulative damage degree D of each component of each dump truck 200 received from the plurality of dump trucks 200 together with the identification information and the position information in a database of the server 310. The database of the server 310 stores, for example, customer information associated with the identification information of each dump truck 200. In addition, the database may be provided outside the server 310. The server 310, for example, generates a list of dump trucks 200 having components whose cumulative damage degree D exceeds a predetermined threshold value, and manages fatigue of the components of the dump trucks 200.

[0065] The information terminal 320 includes, for example, a personal computer installed at a customer's location or a maintenance location of the dump truck 200, and a mobile information terminal held by an operator or maintenance manager of the dump truck 200. The information terminal 320 is connected to the server 310 via a wireless communication line and a network.

[0066] In addition, when the information terminal 320 receives the identification information of the dump truck 200, for example, it obtains the cumulative damage degree D of the parts associated with the identification information from the server 310. In addition, the information terminal 320 receives a list of dump trucks 200 having parts whose cumulative damage degree D exceeds a predetermined threshold from the server 310, for example, based on the identification information of the dump trucks 200 registered in advance.

[0067] As described above, the stress estimation device 100 of the present embodiment includes the storage unit 110 and the calculation unit 120, and estimates the stress S acting on the dump truck 200. The storage unit 110 stores a force calculation formula 111 and a stress calculation formula 112. The force calculation formula 111 is used to calculate the force F acting on a predetermined portion of the dump truck 200 based on the output value of the force sensor 230 that detects the force acting on the suspension devices 203 and 204 of the dump truck 200, or the output value of the acceleration sensor 240 installed in the dump truck 200 and the output value of the force sensor 230. The stress calculation formula 112 is used to calculate the stress S acting on the dump truck 200 based on the force F acting on the predetermined portion of the dump truck 200. The calculation unit 120 includes a force calculation unit 121 and a stress calculation unit 122. The force calculation unit 121 calculates the force F acting on a predetermined portion of the dump truck 200 using the output value of the force sensor 230 or the output values ​​of the acceleration sensor 240 and the force sensor 230 and the force calculation formula 11 stored in the storage unit 110. The stress calculation unit 122 calculates the stress S acting on the dump truck 200 using the force F calculated by the force calculation unit 121 and the stress calculation formula 112 stored in the storage unit 110.

[0068] According to such a configuration, the stress estimation device 100 of the present embodiment first estimates the force F acting on the predetermined portion of the dump truck 200, and then can estimate the stress S acting on the dump truck 200 based on the estimated force F. Therefore, compared with the case where the stress is directly estimated from the output value of the sensor as in the conventional stress calculation system and fatigue management system, the stress S acting on the dump truck 200 can be estimated with higher accuracy. In addition, the storage unit 110 stores a force calculation formula 111 in advance. Therefore, the calculation unit 120 can easily calculate the force F acting on the predetermined portion of the dump truck 200 and its time history waveform based on the output value of the force sensor 230 or the output value of the acceleration sensor 240 and the force sensor 230 and the force calculation formula 111. In addition, the storage unit 110 stores a stress calculation formula 112 in advance, and thus, the calculation unit 120 can easily calculate the stress S acting on the dump truck 200 and its time history waveform based on the stress calculation formula 112 and the force F.

[0069] In the stress estimation device 100 of the present embodiment, the predetermined portion of the dump truck 200 is a portion corresponding to an input position of the force F in the structural analysis for calculating the stress S acting on the dump truck 200 with respect to the analytical model of the dump truck 200. Furthermore, the stress calculation formula 112 is derived from the analytical model of the dump truck 200.

[0070] According to such a configuration, the stress estimating device 100 of the present embodiment can obtain the stress calculation formula 112, which can estimate the stress S acting on the dump truck 200 with high accuracy from the force F acting on a predetermined portion of the dump truck 200 using the analytical model of the dump truck 200. Therefore, according to the stress estimating device 100 of the present embodiment, the stress S acting on the dump truck 200 can be estimated with higher accuracy.

[0071] In the stress estimation device 100 of the present embodiment, the force calculation formula 111 is determined based on the output value of the test force sensor 280 installed in the test dump truck 200A and the output value of the force sensor 230 of the test dump truck 200A, or the output value of the test force sensor 280 of the test dump truck 200A and the output value of the acceleration sensor 240 installed in the test dump truck 200A and the output value of the force sensor 230. The test force sensor 280 is installed in a predetermined portion of the test dump truck 200A having the same configuration as the dump truck 200, and detects the force F acting on the predetermined portion of the test dump truck 200A.

[0072] According to such a configuration, the stress estimating device 100 of the present embodiment can collect the output value of the test force sensor 280 and the output values ​​of the force sensor 230 and the acceleration sensor 240 of the test dump truck 200A by driving the test dump truck 200A. Therefore, the stress estimating device 100 can obtain the force calculation formula 111, which can accurately estimate the force F acting on the predetermined part of the dump truck 200 based on the output value of the force sensor 230 or the output values ​​of the force sensor 230 and the acceleration sensor 240 by analyzing the relationship between the collected detection values ​​of each sensor. Therefore, according to the stress estimating device 100 of the present embodiment, the stress S acting on the dump truck 200 can be estimated with higher accuracy.

[0073] In the stress estimating device 100 of the present embodiment, the predetermined portion of the dump truck 200 includes a plurality of portions 211 of the vehicle frame 210 of the dump truck 200. The vehicle frame 210 is a portion that supports a vehicle body 205 on which the suspension devices 203 and 204 are mounted and on which the cargo of the dump truck 200 is loaded.

[0074] According to this configuration, the stress estimating device 100 of this embodiment can estimate with high accuracy the stress S acting on the frame 210, which is prone to fatigue accumulation due to the relatively large force F acting on the multiple parts 211 from the vehicle body 205 loaded with cargo. Therefore, according to the stress estimating device 100 of this embodiment, the safety of the dump truck 200 can be further improved.

[0075] In the stress estimation device 100 of the present embodiment, an S-N curve 113 between a time-history waveform of stress S acting on a component of the dump truck 200 and a cycle number of stress amplitude is stored in the storage unit 110. In addition, the calculation unit 120 includes a damage degree calculation unit 123 for calculating a cumulative damage degree D of a component of the dump truck 200 using the stress S calculated by the stress calculation unit 122 and the S-N curve 113 stored in the storage unit 110.

[0076] According to this configuration, the stress estimating device 100 of the present embodiment can calculate the cumulative damage degree D of the parts of the dump truck 200 with higher accuracy based on the stress S acting on the dump truck 200 that can be calculated with higher accuracy. As a result, the fatigue management system 300 including the stress estimating device 100 of the present embodiment can manage the fatigue of each part of the plurality of dump trucks 200 with higher accuracy than the conventional fatigue management system, and can promote efficient parts replacement and maintenance.

[0077] As described above, according to this embodiment, it is possible to provide the stress estimating device 100 capable of more accurately estimating the stress S acting on the dump truck 200, and the fatigue management system 300 including the stress estimating device 100. The stress estimating device of the present invention is not limited to the above-described embodiment.

[0078] Figure 6 Yes means Figure 1 A block diagram of a modified example of the stress estimating apparatus 100 is shown. Figure 6 In the illustrated example, the stress estimation apparatus 100 is constituted by, for example, a server 310. That is, the storage unit 110 and the calculation unit 120 of the stress estimation apparatus 100 are implemented by, for example, the CPU of the server 310 executing a program stored in the memory of the server 310.

[0079] In this case, the controller 250 of the dump truck 200 forms a storage unit 251, which stores the force detection value HV output from the force sensor 230, or the acceleration detection value AV output from the acceleration sensor 240 and the force detection value HV output from the force sensor 230, and transmits it to the server 310 via the communication device 270. In addition, the storage unit 251 of the test dump truck 200A also stores the force detection value FV of the test force sensor 280, and transmits it to the server 310 via the communication device 270.

[0080] according to Figure 6 The stress estimation device 100 of the modified example shown can also function as Figure 1That is, the stress estimation device 100 can be constituted by, for example, at least one of the controller 250 of the dump truck 200, the server 310, or the information terminal 320. In addition, the calculation unit 120 may not include the damage degree calculation unit 123, and may include, for example, an index value calculation unit for calculating a fatigue index value as described in Patent Document 3 instead of the damage degree calculation unit 123.

[0081] Although the embodiments of the stress estimating device of the present invention have been described in detail above using the drawings, the specific configuration is not limited to the embodiments, and design changes and the like are possible within the scope of the present invention, and these are also included in the present invention.

[0082] Description of Reference Numerals

[0083] 100 Stress Estimation Device

[0084] 110 Storage Department

[0085] 111 Force Operation Formula

[0086] 112 Stress calculation formula

[0087] 113S-N curve

[0088] 114 Cumulative Damage

[0089] 120 Operation unit

[0090] 121 Force Calculation Unit

[0091] 122 Stress calculation unit

[0092] 123 Damage Calculation Unit

[0093] 200 dump truck

[0094] 200A test dump truck

[0095] 210 frame

[0096] 211 Part of the frame (specified part)

[0097] 203 Suspension

[0098] 204 suspension device

[0099] 205 Body

[0100] 230 force sensor

[0101] 240 Acceleration Sensor

[0102] 280 Test Force Sensor

[0103] D Cumulative damage

[0104] F-Force

[0105] S stress.

Claims

1. A stress estimating device, comprising a storage unit and a computing unit, for estimating stress acting on a dump truck, wherein: The storage unit stores force calculation formulas and stress calculation formulas, wherein: The force calculation formula is used to calculate the force acting on a predetermined part of the dump truck based on the output value of a force sensor detecting the force acting on the suspension device of the dump truck, or the output value of an acceleration sensor installed on the dump truck and the output value of the force sensor, and the stress calculation formula is used to calculate the stress acting on the dump truck based on the force. The calculation unit includes: a force calculation unit that calculates the force using an output value of the force sensor or an output value of the acceleration sensor and the force sensor, and the force calculation formula stored in the storage unit; and a stress calculation unit that calculates stress acting on the dump truck using the force calculated by the force calculation unit and the stress calculation formula stored in the storage unit.

2. The stress estimating device according to claim 1, characterized in that: The predetermined portion is a portion corresponding to an input position of a force in a structural analysis for calculating stress acting on the dump truck with respect to an analytical model of the dump truck. The stress equation is derived from the analytical model.

3. The stress estimating device according to claim 1, characterized in that: The force calculation formula is determined based on the output value of a test force sensor installed on the specified part of the test dump truck having the same structure as the dump truck and detecting the force acting on the specified part of the test dump truck and the output value of the force sensor of the test dump truck, or the output value of the test force sensor, the output value of the acceleration sensor and the output value of the force sensor.

4. The stress estimating device according to claim 1, wherein: The predetermined portion includes a plurality of portions of a frame of the dump truck that supports a vehicle body on which the suspension device is mounted and on which a cargo of the dump truck is loaded.

5. The stress estimating device according to claim 1, wherein: The storage unit stores an S-N curve between a time-history waveform of stress acting on a component of the dump truck and a cycle number of stress amplitude. The calculation unit includes a damage degree calculation unit that calculates a cumulative damage degree of the component based on the stress calculated by the stress calculation unit and the SN curve stored in the storage unit.

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