JP2018115453A - Shovel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shovel capable of precisely warning a replacement time of an attachment.SOLUTION: A shovel 50 according to an embodiment of the present invention comprises: a lower traveling body 1; an upper rotating body 3 mounted on the lower traveling body 1; an excavation attachment attached to the upper rotating body 3; a boom 4 constituting the excavation attachment; and a crack sensor S6 installed at an inside of the boom 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an excavator provided with an attachment.

  There is known an excavator management device that detects a stress applied to an attachment using a strain gauge, calculates a fatigue life of the attachment, and promotes maintenance of the attachment based on the fatigue life (see Patent Document 1).

Japanese Patent No. 5968189

  However, the excavator management device of Patent Document 1 only estimates the fatigue life. Therefore, there is a possibility that maintenance of the attachment may be promoted at an inappropriate timing, and there is room for improvement in that the attachment replacement time is accurately notified.

  In view of the above, it is desirable to provide an excavator that can more accurately notify the attachment replacement time.

  An excavator according to an embodiment of the present invention includes a lower traveling body, an upper swing body mounted on the lower traveling body, an attachment attached to the upper swing body, a work element constituting the attachment, and the work element. And a crack sensor disposed inside.

  The above-described means provides a shovel capable of more accurately notifying the attachment replacement time.

It is a side view of the shovel which concerns on the Example of this invention. It is a top view which shows an example of a crack sensor. It is a figure which shows the structural example of the drive system mounted in the shovel of FIG. It is a figure which shows the structural example of a controller. It is a flowchart which shows the flow of the process at the time of a crack detection. It is a figure which shows arrangement | positioning of the various apparatuses attached to a boom. It is an enlarged view of the area | region VII of FIG. It is a figure for demonstrating the detail of the attachment position of a crack sensor.

  First, an excavator 50 as a construction machine according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a side view of the shovel according to the present embodiment. The upper swing body 3 is mounted on the lower traveling body 1 of the excavator 50 via the swing mechanism 2. A boom 4 is attached to the upper swing body 3. An arm 5 is attached to the tip of the boom 4, and a bucket 6 as an end attachment is attached to the tip of the arm 5.

  The boom 4, the arm 5, and the bucket 6 as work elements constituting an excavation attachment that is an example of the attachment are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, respectively.

  A boom angle sensor S1 is attached to the boom 4, an arm angle sensor S2 is attached to the arm 5, and a bucket angle sensor S3 is attached to the bucket 6. The boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 are collectively referred to as “attitude sensors”.

  The boom angle sensor S1 detects the rotation angle of the boom 4. The boom angle sensor S1 is, for example, an acceleration sensor that detects the rotation angle of the boom 4 with respect to the upper swing body 3 by detecting the inclination of the boom 4 with respect to the horizontal plane.

  The arm angle sensor S2 detects the rotation angle of the arm 5. The arm angle sensor S2 is, for example, an acceleration sensor that detects the rotation angle of the arm 5 relative to the boom 4 by detecting the inclination of the arm 5 with respect to the horizontal plane.

  The bucket angle sensor S3 detects the rotation angle of the bucket 6. The bucket angle sensor S3 is an acceleration sensor that detects the rotation angle of the bucket 6 with respect to the arm 5 by detecting the inclination of the bucket 6 with respect to the horizontal plane, for example.

  The boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 are a potentiometer using a variable resistor, a stroke sensor that detects a stroke amount of a corresponding hydraulic cylinder, and a rotary encoder that detects a rotation angle around a connecting pin. Also, a strain gauge or the like attached to the inside of the attachment may be used.

  The distortion sensor S4 detects the distortion of the attachment. In the present embodiment, the strain sensor S4 is a uniaxial strain gauge that is attached to the inside of the boom 4 and detects strain due to expansion or compression of the boom 4. However, the strain sensor S4 may be a triaxial strain gauge, may be a plurality of uniaxial strain gauges attached to a plurality of locations inside the attachment, or may be a plurality of triaxial strain gauges, It may be a combination of one or more uniaxial strain gauges and one or more triaxial strain gauges. Further, the strain sensor S4 may be attached to the outer surface of the boom 4 or may be omitted.

  The upper swing body 3 is provided with a cabin 10, and a power source such as an engine 11 and a vehicle body tilt sensor S5 are mounted thereon. A controller 30, an input device D 1, a sound output device D 2, a display device D 3, a storage device D 4, and an engine controller D 6 are provided in the cabin 10, and a communication device D 5 is provided outside the cabin 10.

  The vehicle body inclination sensor S5 detects the inclination angle of the vehicle body of the excavator 50. In the present embodiment, the vehicle body inclination sensor S5 is an acceleration sensor that detects the inclination angle of the vehicle body with respect to the horizontal plane. The inclination angle of the vehicle body may be derived from, for example, the output of a strain gauge attached to the inside of each of the left and right surfaces of the boom 4. In this case, by combining the output of the acceleration sensor as the vehicle body tilt sensor S5 and the output of the strain gauge, it is possible to calculate the tilt angles of the upper, lower, left and right vehicle bodies.

  The crack sensor S6 detects a crack (crack) generated on the surface of the work element constituting the attachment. The surface of the working element includes an inner surface and an outer surface. The detection of the crack includes the presence / absence of the occurrence of a crack, the length of the crack, the progress rate of the crack and the like.

  FIG. 2 is a plan view showing an example of the crack sensor S6. In the example of FIG. 2, the crack sensor S <b> 6 is a crack gauge composed of a number of grid lines GL that connect the terminals A and B, and is attached to the surface of the work element. As shown in the drawing, when the crack CR extending in the + Y direction reaches the crack sensor S6, the grid line GL on the leftmost side (−Y side) is disconnected. As a result, the resistance value between the terminals increases. The crack sensor S6 detects the resistance value between the terminals. For example, the crack sensor S6 outputs a signal (crack generation signal) indicating that a crack CR has occurred when the resistance value is larger than the initial resistance value when the grid line GL is not disconnected to the outside. To do. The resistance value itself may be output to the outside. As the crack CR progresses in the + Y direction, the grid line GL is disconnected in order from the -Y side. The resistance value between the terminals increases as the number of disconnected grid lines increases. The crack sensor S6 may derive and output the length of the crack CR based on the resistance value, and may derive and output the progress rate of the crack CR based on the temporal change of the resistance value. In the present embodiment, the crack sensor S6 is affixed to the inner surface in the interior space of the boom 4. Details of the arrangement of the crack sensor S6 will be described later.

  The crack sensor S6 may be an image sensor. In this case, the crack sensor S6 includes an illumination device, illuminates the surface of the work element at predetermined time intervals, captures an image of the surface, and outputs the captured image to the outside. When a crack is detected by executing predetermined image processing, the detection result may be output to the outside.

  The controller 30 is a control device that functions as a main control unit that performs drive control of the excavator 50. The controller 30 includes an arithmetic processing unit that includes a CPU and an internal memory. Various functions of the controller 30 are realized by the CPU executing programs stored in the internal memory.

  The input device D1 is a device for the operator of the excavator 50 to input various information to the controller 30. The input device D1 includes, for example, a membrane switch provided on the surface of the display device D3. Further, the input device D1 may be a touch panel or the like.

  The audio output device D <b> 2 outputs various audio information in response to commands from the controller 30. The audio output device D2 is, for example, an in-vehicle speaker connected to the controller 30. The audio output device D2 may be an alarm device such as a buzzer.

  The display device D3 displays a screen including various types of information in response to a command from the controller 30. The display device D3 is an on-vehicle liquid crystal display connected to the controller 30, for example.

  The storage device D4 is a device for storing various information. The storage device D4 is a non-volatile storage medium such as a semiconductor memory, for example. In this embodiment, the storage device D4 stores the detected values of the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3, the strain sensor S4, the vehicle body tilt sensor S5, the crack sensor S6, etc., the output value of the controller 30, and the like. To do.

  The communication device D5 is a device that controls wireless communication between the controller 30 and a device outside the controller 30.

  The engine controller D6 is a device that controls the engine 11. In the present embodiment, the engine controller D6 executes isochronous control for maintaining the engine 11 at a predetermined engine speed by controlling the fuel injection amount and the like.

  FIG. 3 is a diagram illustrating a configuration example of a drive system mounted on the excavator 50. The mechanical drive system, the high-pressure hydraulic line, the pilot line, and the electric control system are indicated by a double line, a solid line, a broken line, and a dotted line, respectively. .

  The drive system of the excavator 50 mainly includes an engine 11, main pumps 14 </ b> L and 14 </ b> R, a pilot pump 15, a control valve 17, an operation device 26, a pressure sensor 29, and a controller 30.

  The engine 11 is, for example, a diesel engine that operates so as to maintain a predetermined rotational speed. The output shaft of the engine 11 is connected to the input shafts of the main pumps 14L and 14R and the pilot pump 15.

  The main pumps 14L and 14R are devices for supplying hydraulic oil to the control valve 17 via a high pressure hydraulic line, and are, for example, swash plate type variable displacement hydraulic pumps.

  The pilot pump 15 is a device for supplying hydraulic oil to various hydraulic control devices including the operation device 26 via the pilot line 25, and is, for example, a fixed displacement hydraulic pump.

  The control valve 17 is a hydraulic control device that controls the hydraulic system in the excavator 50. Specifically, the control valve 17 includes flow control valves 171 to 176 that control the flow of hydraulic oil discharged from the main pumps 14L and 14R. The control valve 17 is connected to the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, the left traveling hydraulic motor 1A, the right traveling hydraulic motor 1B, and the turning hydraulic motor 2A through the flow control valves 171-176. The hydraulic oil discharged from the main pumps 14L and 14R is selectively supplied to one or a plurality of ones. Hereinafter, the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, the left traveling hydraulic motor 1A, the right traveling hydraulic motor 1B, and the turning hydraulic motor 2A are collectively referred to as “hydraulic actuators”.

  The operating device 26 is a device used by an operator for operating the hydraulic actuator. In this embodiment, the operating device 26 supplies the hydraulic oil discharged from the pilot pump 15 to the pilot ports of the flow control valves corresponding to the hydraulic actuators via the pilot line 25. The hydraulic oil pressure (pilot pressure) supplied to each pilot port is a pressure corresponding to the operating direction and operating amount of the lever or pedal of the operating device 26 corresponding to each hydraulic actuator.

  The pressure sensor 29 is an example of an operation content detection unit for detecting the operation content of the operator using the operation device 26. In this embodiment, the pressure sensor 29 detects the operation direction and operation amount of the lever or pedal of the operation device 26 corresponding to each of the hydraulic actuators in the form of pressure, and outputs the detected value to the controller 30. The operation content of the operation device 26 may be derived using the output of a sensor other than the pressure sensor such as a potentiometer.

  The center bypass conduit 40L is a high-pressure hydraulic line that passes through the flow control valves 171, 173, and 175 disposed in the control valve 17. The center bypass conduit 40R is a flow control valve disposed in the control valve 17. High pressure hydraulic lines through 172, 174 and 176.

  The flow rate control valve 171 is a spool valve that controls the flow rate and the flow direction of the hydraulic oil between the main pump 14L, the left-side traveling hydraulic motor 1A, and the hydraulic oil tank. The flow rate control valve 172 is a spool valve that controls the flow rate and flow direction of hydraulic fluid between the main pump 14R, the right-side traveling hydraulic motor 1B, and the hydraulic fluid tank. The flow rate control valve 173 is a spool valve that controls the flow rate and the flow direction of the hydraulic oil between the main pump 14L, the turning hydraulic motor 2A, and the hydraulic oil tank.

  The flow rate control valve 174 is a spool valve that controls the flow rate and the flow direction of the hydraulic oil among the main pump 14R, the bucket cylinder 9, and the hydraulic oil tank. The flow rate control valve 175 is a spool valve that controls the flow rate and flow direction of hydraulic fluid among the main pump 14L, the arm cylinder 8, and the hydraulic oil tank. The flow rate control valve 176 is a spool valve that controls the flow rate and flow direction of hydraulic oil between the main pump 14R, the boom cylinder 7, and the hydraulic oil tank.

  Next, various functions provided in the controller 30 will be described with reference to FIG. FIG. 4 is a diagram illustrating a configuration example of the controller 30.

  The controller 30 receives information from the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3, the strain sensor S4, the vehicle body tilt sensor S5, the crack sensor S6, the pressure sensor 29, the input device D1, and the like.

  In the present embodiment, the controller 30 receives information from the strain sensor S4 and the crack sensor S6 attached inside the boom 4 via wireless communication. Specifically, information transmitted wirelessly by the transmitter D7 connected to the strain sensor S4 and the crack sensor S6 is received using the communication device D5 attached to the upper swing body 3.

  The transmitter D7 is a device that wirelessly transmits the detection value of the sensor attached to the work element. In this embodiment, the transmitter D7 is attached to the inside of the boom 4, which is the same attachment object as the strain sensor S4 and the crack sensor S6. The transmitter D7 may be attached to the outer surface of the boom 4.

  The strain sensor S4, the crack sensor S6, and the transmitter D7 are connected to the vibration generator D8 and receive power from the vibration generator D8.

  The vibration generator D8 is a device that converts vibration energy into electric energy. In this embodiment, the vibration generator D8 is an electromagnetic induction generator, and is attached to the inside of the boom 4, which is the same attachment object as the strain sensor S4, the crack sensor S6, and the transmitter D7. However, the vibration generator D8 may be an electrostatic induction generator, a piezoelectric generator, or the like. Further, the vibration generator D8 may be attached to the outer surface of the boom 4.

  The controller 30 executes various calculations based on the received information and the information stored in the storage device D4, and outputs a control signal to the audio output device D2, the display device D3, the engine controller D6, etc. according to the calculation results. To do. Further, the controller 30 may wirelessly transmit information, calculation results, and the like received via the communication device D5 to the outside.

  The posture deriving unit 301 is a functional element that detects the posture of the attachment. In the present embodiment, the posture deriving unit 301 derives the posture of the excavation attachment based on the output of the posture sensor configured by the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3.

  The weight deriving unit 302 is a functional element that derives the weight of an object being lifted by the attachment (hereinafter referred to as “lifting weight”). In the present embodiment, the weight deriving unit 302 derives the lifting weight based on the attitude of the excavation attachment detected by the attitude sensor and the distortion of the excavation attachment detected by the strain sensor S4.

  For example, the weight deriving unit 302 derives the lifted weight by referring to the correspondence table using, as input keys, the distortion of the excavation attachment, the attitude of the excavation attachment, the shape of the excavation attachment, the attachment position of the strain gauge, and the like. The correspondence table is a reference table that stores the correspondence relationship between the attitude of the excavation attachment, the distortion of the excavation attachment, and the lifting weight, and is stored in advance in the storage device D4. The correspondence relationship is determined in advance based on FEM analysis or the like. For example, the weight deriving unit 302 selects a combination closest to the combination of the current excavation attachment posture and strain from the correspondence table, and stores the value of the lift weight stored in association with the selected combination as the current lift. Derived as weight. The distortion of a drilling attachment means the distortion in the 1 or several site | part in a drilling attachment.

  Alternatively, the weight deriving unit 302 may derive the lifting weight by substituting the excavation attachment distortion and the excavation attachment posture into a pre-stored calculation formula. The calculation formula is stored in advance in the storage device D4.

  The crack detection unit 303 is a functional element that detects a crack. In the present embodiment, the crack detection unit 303 detects a crack based on the output of the crack sensor S6.

  For example, the crack detection unit 303 receives the resistance value output from the crack sensor S6 via the transmitter D7 and the communication device D5. Then, the occurrence of a crack is detected when the received resistance value exceeds a predetermined value.

  When detecting a crack, the crack detection unit 303 may output a control command to at least one of the audio output device D2, the display device D3, the communication device D5, and the engine controller D6. For example, the crack detection unit 303 may display that the crack has been detected on the display device D3, and may output a sound through the sound output device D2. In addition, the crack detection unit 303 may wirelessly transmit information regarding the crack to the outside via the communication device D5. Further, the output of the engine 11 may be reduced via the engine controller D6, or the engine 11 may be stopped.

  The posture deriving unit 301, the weight deriving unit 302, and the crack detecting unit 303 may be realized by an external control device outside the shovel. The external control device is an arithmetic processing device including a CPU and an internal memory, like the controller 30. In this case, the controller 30 wirelessly transmits the received information to the external control device through the communication device D5. The strain sensor S4 and the crack sensor S6 may wirelessly transmit the detected value to the external control device through the transmitter D7 and the communication device D5 of the controller 30, or may transmit the detected value wirelessly to the external control device through the transmitter D7. Good.

  Next, a process when the controller 30 detects a crack (hereinafter referred to as “crack detection process”) will be described with reference to FIG. FIG. 5 is a flowchart showing a flow of processing at the time of detecting a crack.

  First, the crack detection unit 303 of the controller 30 determines whether or not a crack has occurred (step ST1). In the present embodiment, the crack detection unit 303 determines whether or not a crack has occurred inside the boom 4 based on the output of the crack sensor S6 attached inside the boom 4.

  Specifically, the crack detection unit 303 acquires the output of the crack sensor S6 via the communication device D5 and the transmitter D7. In the configuration in which the crack sensor S6 continuously outputs the resistance value between the terminals, the crack detection unit 303 determines whether or not the resistance value exceeds a predetermined value. When it is determined that the resistance value exceeds a predetermined value, it is determined that a crack has occurred inside the boom 4. Thus, in the configuration in which the crack sensor S6 outputs a crack occurrence signal when a crack occurs, the crack detection unit 303 determines that a crack has occurred inside the boom 4 when the crack occurrence signal is received.

  When it determines with the crack not having generate | occur | produced (NO of step ST1), the crack detection part 303 repeats determination of step ST1.

  When it determines with the crack having generate | occur | produced (YES of step ST1), the crack detection part 303 preserve | saves the attachment information before and behind crack generation (step ST2). In the present embodiment, the controller 30 stores information related to the attitude of the excavation attachment in excavation / turning work, information related to the lifting weight, etc. as attachment information in a time series and temporarily over a predetermined time. For example, it is stored in the storage device D4 until it is overwritten with subsequent information. The information related to the attitude of the excavation attachment includes an output of the attitude sensor and the like. Information about the lifting weight includes the output of the strain sensor S4 and the like. Furthermore, the controller 30 may store information on the turning work and the like in time series and temporarily. In this case, the information related to the turning work may include information related to the turning acceleration.

  And if it determines with the crack having generate | occur | produced, the crack detection part 303 will preserve | save the attachment information memorize | stored in the memory | storage device D4 after the time of going back only predetermined time from the present time. For example, it is stored in another area of the storage device D4 so as not to be overwritten by subsequent information. Or you may memorize | store in the non-volatile storage medium different from the memory | storage device D4. Similarly, the crack detection part 303 preserve | saves the attachment information acquired over predetermined time after the present time.

  With this configuration, the controller 30 can present attachment information before and after the occurrence of a crack to related parties such as an administrator. Stakeholders look at the attachment information to determine the details of the excavation work up to the occurrence of the crack, the details of the excavation work that directly caused the crack, the excavation work after the crack occurred, and the progress rate of the crack. Can understand the relationship. In addition, when the attachment information includes information related to the turning work, the person concerned must confirm the contents of the turning work up to the occurrence of the crack, the contents of the turning work that directly caused the crack, and the turning work after the crack has occurred. And the relationship between the crack growth rate and the like. Moreover, since the progress rate of a crack can be grasped | ascertained quantitatively, the remaining life of a drilling attachment can be estimated.

  Next, with reference to FIG. 6 and FIG. 7, the mounting positions of the strain sensor S4, crack sensor S6, transmitter D7, and vibration generator D8 in the boom 4 will be described. FIG. 6 is a perspective view of the boom 4, and FIG. 7 is an enlarged view of a region VII in FIG. 6. In the figure, a one-dot chain line represents a power line, a dotted line represents a signal line, and a broken line represents a hidden line.

  In the embodiment shown in FIGS. 6 and 7, the strain sensor S4 is provided between the boom cylinder boss 4a and the boom top 4c so as to detect the distortion of the boom 4 in the longitudinal direction of the boom 4 (the longitudinal direction of the excavation attachment). And attached to the inner surface of the metal plate on the ventral side (−Z side) of the boom 4. However, the strain sensor S4 may be attached to the inner surface of the metal plate on the back side (+ Z side) of the boom 4, and the metal on the back side or the ventral side of the boom 4 between the boom cylinder boss 4a and the boom foot 4b. It may be attached to the inner surface of the plate. Further, the strain sensor S4 may be attached to the surface of the partition wall 4e inside the boom 4 or the like.

  The transmitter D7 is attached to the inner surface of the metal plate on the ventral side (-Z side) of the boom 4 between the boom cylinder boss 4a and the boom top 4c. However, the transmitter D7 may be attached to the inner surface of the metal plate on the back side (+ Z side) of the boom 4, and the metal plate on the back side or the ventral side of the boom 4 between the boom cylinder boss 4a and the boom foot 4b. It may be attached to the inner surface. Further, the transmitter D7 may be attached to the surface of the partition wall 4e inside the boom 4 or the like.

  The vibration generator D8 is attached in the vicinity of the boom top 4c. However, the vibration generator D8 may be attached to other parts where vibration is likely to occur, for example, in the vicinity of the boom foot 4b, in the vicinity of the boom cylinder boss 4a, or in the vicinity of the bracket 4d. In this embodiment, the vibration generator D8 is attached to the inner surface of the metal plate on the ventral side (-Z side) of the boom 4, but is attached to the inner surface of the metal plate on the back side (+ Z side) of the boom 4. Also good. The vibration generator D8 may be attached to the surface of the partition wall 4e inside the boom 4 or the like.

  The crack sensor S6 is attached to the surface on the proximal side (−X side) of the partition wall 4e between the boom cylinder boss 4a and the boom top 4c. However, it may be attached to the surface on the distal side (+ X side).

  FIG. 8 is a diagram for explaining details of the attachment position of the crack sensor S6. Specifically, FIG. 8 is a perspective view showing a vertical cross section of the welded portion between the metal plate 4f on the ventral side of the boom 4 and the partition wall 4e. In the example of FIG. 8, three crack sensors S61 to S63 pasted at the welded portion WM for welding the partition 4e and the metal plate 4f are shown.

  The crack sensor S61 is affixed in order to detect a crack CR1 that occurs at the upper toe portion of the welded portion WM. Specifically, a part is affixed on the surface of the partition 4e, and the remaining part is bent so that it affixes on the surface of the welding part WM. The partition 4e is preferably designed so that it develops along the upper toe (along the Y axis) after the crack CR1 occurs at the upper toe. That is, a place where the crack CR1 is likely to occur is specified in advance.

  The crack sensor S62 is affixed to detect a crack CR2 that occurs at the root of the weld WM and reaches the surface of the weld WM. The surface of the weld WM may be processed to be a flat surface. This is to make it easier to attach the crack sensor S62. The metal plate 4f is preferably designed so that it propagates along the root portion (along the Y axis) after the crack CR2 occurs at the root portion.

  The crack sensor S63 is affixed in order to detect a crack CR3 that occurs at the lower end of the welded portion WM. Specifically, it is bent so that a part is affixed to the surface of the metal plate 4f and the remaining part is affixed to the surface of the weld WM. The metal plate 4f is preferably designed such that it propagates along the lower stop (along the Y axis) after the crack CR3 has occurred at the lower stop.

  In the example of FIG. 8, in the lateral direction (Y-axis direction), the crack sensor S63 is attached to the leftmost side (−Y side), and the crack sensor S62 is attached to the rightmost side (+ Y side). S61 is pasted between them. However, the positional relationship in the horizontal direction is arbitrary, and, for example, three crack sensors S61 to S63 may be attached at the same position in the horizontal direction. Further, the width (the length in the Y-axis direction), the number, the interval in the case of a plurality of crack sensors S61 to S63, etc. are arbitrary, for example, even if they have the same width as the width of the metal plate 4f. Good. Preferably, the width, number, interval, and the like of each of the crack sensors S61 to S63 are minimized by preliminarily limiting the places where cracks are likely to occur by design.

  With the above-described configuration, the controller 30 can more accurately notify the attachment replacement time. Specifically, the controller 30 can detect cracks occurring in the boom 4 at an early stage. The person concerned can detect the occurrence of a crack that cannot be seen from the outside at an early stage. For example, the person concerned can know that the cracks CR2 and CR3 have occurred before the cracks CR2 and CR3 reach the outer surface of the metal plate 4f. Therefore, the boom 4 can be replaced at an appropriate timing, and the boom 4 (excavator) can be prevented from becoming unusable due to fatigue failure or the like during excavation work.

  The excavator 50 also enables power supply from the vibration generator D8 attached to the boom 4 to the strain sensor S4, crack sensor S6, and transmitter D7 attached to the boom 4. Therefore, wireless communication between each of the strain sensor S4 and the crack sensor S6 and the controller 30 can be established. In addition, a power line between each of the strain sensor S4 and the crack sensor S6 and the power source mounted on the upper swing body 3, a battery for supplying power to each of the strain sensor S4 and the crack sensor S6, and the like can be eliminated. As a result, the measurement of the distortion of the boom 4 using the distortion sensor S4 can be stably realized in real time over a long period of time. Moreover, the detection of the crack using the crack sensor S6 can be stably realized in real time and for a long time.

  In addition, the excavator 50 arranges the strain sensor S4, the crack sensor S6, the transmitter D7, and the vibration generator D8 inside the boom 4 to isolate them from the external environment. Therefore, measurement of the distortion of the boom 4 using the strain sensor S4 at the work site, detection of a crack using the crack sensor S6, and the like can be realized more stably and more reliably.

  Further, the above description relates to a crack generated at the welded portion WM for welding the metal plate 4f on the belly side (−Z side) of the boom 4 and the partition wall 4e. However, the above description is about cracks generated at the welded portion WM that welds the metal plate on the back side (+ Z side), the left side (−Y side), and the right side (+ Y side) of the boom 4 to the partition wall 4e. The same applies.

  The above description relates to the mounting positions of the strain sensor S4, the crack sensor S6, the transmitter D7, and the vibration generator D8 inside the boom 4. However, the above description is similarly applied to the mounting position inside the arm 5.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, the strain sensor S4, the crack sensor S6, and the transmitter D7 may be supplied with power from an external power source. For example, you may be connected to the electrical storage apparatus mounted in the upper turning body 3 through the power line.

  The strain sensor S4, the crack sensor S6, and the transmitter D7 may be driven by a primary battery, a secondary battery capable of non-contact charging, or the like. In this case, the vibration generator D8 is omitted. The strain sensor S4 and the crack sensor S6 may be wired to an external device such as the controller 30 for signal transmission. In this case, the transmitter D7 is omitted. The weight deriving unit 302 may derive the lifting weight based on the output of a sensor other than the strain sensor S4, such as a boom cylinder pressure sensor. In this case, the strain sensor S4 is omitted. Further, the derivation of the lifting weight itself may be omitted. In this case, the weight deriving unit 302 is omitted.

  DESCRIPTION OF SYMBOLS 1 ... Lower traveling body 1A ... Left-side traveling hydraulic motor 1B ... Right-side traveling hydraulic motor 2 ... Turning mechanism 2A ... Turning hydraulic motor 3 ... Upper turning body 4 ... Boom 4a ... Boom cylinder boss 4b ... Boom foot 4c ... Boom top 4d ... Bracket 4e ... Bulkhead 4f ... Metal plate 5 ... Arm 6 ... Bucket 7 ... Boom Cylinder 8 ... Arm cylinder 9 ... Bucket cylinder 10 ... Cabin 11 ... Engine 14L, 14R ... Main pump 15 ... Pilot pump 17 ... Control valve 25 ... Pilot line 26 ... Operating device 29 ... Pressure sensor 30 ... Controller 40L, 40R ... Center bypass pipe 50 ... Excavators 171-176 ... Flow rate control valve 301 ... Attitude derivation section 302 ... Weight derivation section 303 ... Crack detection section CR, CR1 to CR3 ... Crack D1 ... Input device D2 ... Audio output device D3 ... Display device D4 ... Storage device D5 ... Communication device D6 ... Engine controller D7 ... Transmitter D8 ... Vibration generator S1 ... Boom angle sensor S2 ... Arm angle sensor S3 ... Bucket angle sensor S4 ... Distortion sensor S5 ... Car body tilt sensor S6, S61-S63 ... Crack sensor WM ... Welded part

Claims (3)

A lower traveling body,
An upper swing body mounted on the lower traveling body;
An attachment attached to the upper swing body;
Working elements constituting the attachment;
A crack sensor disposed inside the working element,
Excavator. A vibration generator for supplying power to the crack sensor;
The excavator according to claim 1. The working element is a boom;
The crack sensor is affixed to a welded portion of a partition wall inside the boom,
The shovel according to claim 1 or 2.

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