JP7059309B2 - Excavator and excavator weight calculator - Google Patents

Description

The present invention relates to a shovel with an attachment.

A hydraulic excavator work amount monitoring device for loading an object into a dump truck is known (see Patent Document 1). This workload monitoring device is a bucket containing booms, arms, and earth and sand based on the hydraulic oil pressure on the bottom side of the boom cylinder (boom bottom pressure) and the hydraulic oil pressure on the rod side (boom rod pressure). Derives the force that supports the excavation attachment made up of. It also derives a moment around the boom support pin of the drilling attachment based on the boom angle, arm angle, and bucket angle and the weight of each of the boom, arm, and empty bucket. Then, the weight of the earth and sand in the bucket is derived from the balance between the supporting force and the moment around the boom support pin.

Japanese Unexamined Patent Publication No. 2002-285589

However, since the above-mentioned work amount monitoring device derives a force to support the excavation attachment based on the boom bottom pressure and the boom rod pressure, if the bucket moves up and down and does not move stably and horizontally, the surge pressure etc. is added to the pressure detection value. Will occur, and the weight of the earth and sand in the bucket may not be derived with high accuracy. When a skilled operator performs excavation and loading operations, he also raises and lowers the boom during turning, and this point cannot be ignored.

In view of the above, it is desired to provide a shovel that can derive the amount of work at various customer sites with high accuracy.

The excavator according to the embodiment of the present invention has a lower traveling body, an upper swivel body mounted on the lower traveling body, an attachment attached to the upper swivel body and including a bucket, and a posture for detecting the posture of the attachment. The control device includes a sensor and a control device that derives the loading weight in each cycle of excavation / loading based on the differential pressure between the attitude sensor and the boom cylinder or the strain sensor attached to the attachment. Based on the image captured by the apparatus, it is determined that the attachment is facing the direction of the dump truck, and then, when a turning operation with respect to the upper swivel body is performed, it is determined that the dump operation is completed, or the above. The completion of the dump operation is determined based on the pressure sensor that detects the amount of operation on the bucket cylinder that operates the bucket by pressure, and when the dump operation is completed, one dump truck is accumulated by accumulating the loaded weight for each cycle. The total load weight of the earth and sand loaded in is derived.

By the above-mentioned means, a shovel that derives the amount of work at various customer sites with high accuracy is provided.

It is a side view of the excavator which concerns on embodiment of this invention. It is a figure which shows the structural example of the drive system mounted on the excavator of FIG. It is a figure explaining the excavation / loading operation. It is a figure which shows the configuration example of a controller. It is a flowchart which shows the flow of weight derivation processing. It is a figure which shows the arrangement of the distortion sensor attached to a boom. It is a figure which shows the arrangement of the distortion sensor attached to a boom. It is a flowchart which shows another flow of the weight derivation process. It is a figure explaining the torsional load acting on the excavation attachment. It is a schematic diagram of the communication network to which the excavator of FIG. 1 is connected.

First, the excavator (excavator) 50 as a construction machine according to the embodiment of the present invention will be described with reference to FIG. Note that FIG. 1 is a side view of the excavator according to the present embodiment. The upper swivel body 3 is mounted on the lower traveling body 1 of the excavator 50 via the swivel 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, arm 5, and bucket 6 as working elements constituting the excavation attachment, which is an example of the attachment, are hydraulically driven by the boom cylinder 7, the arm cylinder 8, and the 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 a "posture sensor".

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 with respect 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, for example, 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. 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 the stroke amount of the corresponding hydraulic cylinder, and a rotary encoder that detects the rotation angle around the connecting pin. And so on.

The strain sensor S4 detects the distortion of the attachment. In this embodiment, the strain sensor S4 is a uniaxial strain gauge attached to the surface of the boom 4 to detect strain due to expansion or compression of the boom 4. However, the strain sensor S4 may be a 3-axis strain gauge, a plurality of 1-axis strain gauges attached to a plurality of attachment points, a plurality of 3-axis strain gauges, or 1 or a plurality of 3-axis strain gauges. It may be a combination of a plurality of uniaxial strain gauges and one or a plurality of triaxial strain gauges.

The upper swing body 3 is provided with a cabin 10, and is equipped with a power source such as an engine 11 and a vehicle body tilt sensor S5. A controller 30, an input device D1, a voice output device D2, a display device D3, a storage device D4, and an engine controller D6 are provided in the cabin 10, and a communication device D5 is provided outside the cabin 10.

The vehicle body tilt sensor S5 detects the tilt angle of the vehicle body of the excavator 50. In this embodiment, the vehicle body tilt sensor S5 is an acceleration sensor that detects the tilt angle of the vehicle body with respect to the horizontal plane. The tilt angle of the vehicle body may be derived from, for example, the output of a strain gauge attached to the top, bottom, left, and right surfaces of the boom 4. In this case, the vehicle body tilt sensor S5 may be omitted.

The controller 30 is a control device that functions as a main control unit that controls the drive of the shovel 50. The controller 30 is composed of an arithmetic processing unit including a CPU and an internal memory. Various functions of the controller 30 are realized by the CPU executing a program stored in the internal memory.

The input device D1 is a device for the operator of the shovel 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 voice output device D2 outputs various voice information in response to a command from the controller 30. The audio output device D2 is, for example, an in-vehicle speaker connected to the controller 30. Further, the audio output device D2 may be an alarm device such as a buzzer.

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

The storage device D4 is a device for storing various types of information. The storage device D4 is a non-volatile storage medium such as a semiconductor memory. In this embodiment, the storage device D4 stores the detection 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, etc., the output value of the controller 30, and the like.

The communication device D5 is a device that controls wireless communication between the controller 30 and a device outside the shovel 50.

The engine controller D6 is a device that controls the engine 11. In this embodiment, the engine controller D6 controls the fuel injection amount and the like to execute isochronous control for maintaining the engine 11 at a predetermined engine speed.

FIG. 2 is a diagram showing a configuration example of a drive system mounted on the excavator 50, in which a mechanical drive system, a high-pressure hydraulic line, a pilot line, and an electric control system are shown by double lines, solid lines, broken lines, and dotted lines, respectively. ..

The drive system of the excavator 50 mainly includes an engine 11, a main pump 14L, 14R, a pilot pump 15, a control valve 17, an operating 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 rotation speed. Further, 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 an operating device 26 via a pilot line 25, and is, for example, a fixed capacity hydraulic pump.

The control valve 17 is a hydraulic control device that controls the hydraulic system in the shovel 50. Specifically, the control valve 17 includes flow rate control valves 171 to 176 that control the flow of hydraulic oil discharged by the main pumps 14L and 14R. The control valve 17 is one of the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, the left hydraulic motor 1A, the right hydraulic motor 1B, and the turning hydraulic motor 2A through the flow control valves 171 to 176. The hydraulic oil discharged by the main pumps 14L and 14R is selectively supplied to one or more of them. In the following, the boom cylinder 7, arm cylinder 8, bucket cylinder 9, left-side traveling hydraulic motor 1A, right-side traveling hydraulic motor 1B, and turning hydraulic motor 2A are collectively referred to as "hydraulic actuators".

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

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 operating direction and operating amount of the lever or pedal of the operating 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 by using the output of a sensor other than the pressure sensor such as a potentiometer.

The center bypass pipe 40L is a high-pressure hydraulic line passing through the flow control valves 171, 173, and 175 arranged in the control valve 17, and the center bypass pipe 40R is a flow control valve arranged in the control valve 17. A high pressure hydraulic line passing through 172, 174, and 176.

The flow rate control valve 171 is a spool valve that controls the flow rate and flow direction of the hydraulic oil between the main pump 14L, the hydraulic motor 1A for traveling on the left side, and the hydraulic oil tank. Further, the flow rate control valve 172 is a spool valve that controls the flow rate and flow direction of the hydraulic oil between the main pump 14R, the hydraulic motor 1B for traveling on the right side, and the hydraulic oil tank. Further, the flow rate control valve 173 is a spool valve that controls the flow rate and 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 flow direction of the hydraulic oil between the main pump 14R, the bucket cylinder 9, and the hydraulic oil tank. Further, the flow rate control valve 175 is a spool valve that controls the flow rate and the flow direction of the hydraulic oil between the main pump 14L, the arm cylinder 8, and the hydraulic oil tank. Further, the flow rate control valve 176 is a spool valve that controls the flow rate and the flow direction of the hydraulic oil between the main pump 14R, the boom cylinder 7, and the hydraulic oil tank.

Next, the excavation / loading operation, which is an example of the operation of the excavator 50, will be described with reference to FIG. First, as shown in FIG. 3A, the operator swivels the upper swivel body 3 so that the tip of the bucket 6 is at a desired height from the excavation target with the arm 5 and the bucket 6 open, and the bucket. 6 is lowered. When turning the upper swing body 3 and lowering the boom 4, the operator visually confirms the position of the bucket 6. Generally, the upper swing body 3 is turned and the boom 4 is lowered at the same time. The above operation is referred to as a boom lowering turning operation, and this operation section is referred to as a boom lowering turning operation section.

When the operator determines that the tip of the bucket 6 has reached a desired height, the operator closes the arm 5 until the arm 5 is substantially perpendicular to the ground, as shown in FIG. 3 (B). As a result, soil of a predetermined depth is excavated and the arm 5 is scraped by the bucket 6 until it is substantially perpendicular to the ground surface. Next, the operator further closes the arm 5 and the bucket 6 as shown in FIG. 3 (C), and the bucket 6 is substantially perpendicular to the arm 5 as shown in FIG. 3 (D). Close 6 That is, the bucket 6 is closed until the upper edge of the bucket 6 becomes substantially horizontal, and the collected soil is stored in the bucket 6. The above operation is referred to as an excavation operation, and this operation section is referred to as an excavation operation section.

Next, when the operator determines that the bucket 6 is closed until it is substantially perpendicular to the arm 5, the bottom of the bucket 6 is desired from the ground while the bucket 6 is closed, as shown in FIG. 3 (E). Raise the boom 4 until it reaches the height of. This operation is referred to as a boom raising operation, and this operation section is referred to as a boom raising operation section. Following or at the same time as this operation, the operator swivels the upper swivel body 3 and swivels the bucket 6 to the soil removal position as indicated by the arrow AR1. This operation including the boom raising operation is referred to as a boom raising turning operation, and this operation section is referred to as a boom raising turning operation section.

Raising the boom 4 until the bottom of the bucket 6 reaches the desired height is, for example, when the dump truck is dumped to the loading platform, the bucket 6 must be lifted higher than the height of the loading platform or the bucket 6 will hit the loading platform. Because.

Next, when the operator determines that the boom raising and turning operation is completed, the arm 5 and the bucket 6 are opened as shown in FIG. 3 (F), and the soil in the bucket 6 is discharged. This operation is referred to as a dump operation, and this operation section is referred to as a dump operation section. In the dump operation, only the bucket 6 may be opened and the soil may be discharged.

Next, when the operator determines that the dump operation is completed, as shown in FIG. 3 (G), the upper swivel body 3 is swiveled as shown by the arrow AR2, and the bucket 6 is placed directly above the excavation position. Move it. At this time, at the same time as turning, the boom 4 is lowered to lower the bucket 6 from the excavation target to a desired height. This operation is a part of the boom lowering turning operation described with reference to FIG. 3 (A). As shown in FIG. 3A, the operator lowers the bucket 6 to a desired height so as to perform the operation after the excavation operation again.

The operator proceeds with excavation and loading while repeating this cycle with the above-mentioned "boom lowering turning operation", "excavation operation", "boom raising turning operation", and "dumping operation" as one cycle.

Next, with reference to FIG. 4, various functions provided in the controller 30 will be described. FIG. 4 is a diagram showing 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 input device D1, the pressure sensor 29, and the like.

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

The posture deriving unit 301 is a functional element that detects the posture of the attachment. In this embodiment, the posture deriving unit 301 derives the posture of the excavation attachment based on the output of the posture sensor including 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 for deriving the weight of the object being lifted by the attachment (hereinafter referred to as "lifting weight"). In this embodiment, the weight derivation unit 302 derives the lift weight based on the posture of the excavation attachment detected by the attitude sensor and the strain of the excavation attachment detected by the strain sensor S4 when a predetermined derivation condition is satisfied. ..

For example, the weight deriving unit 302 derives the lifting weight by referring to the corresponding table using the distortion of the excavation attachment, the posture of the excavation attachment, the shape of the excavation attachment, the attachment position of the strain gauge, and the like as input keys. The correspondence table is a reference table that stores the correspondence between the posture 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 and the like. For example, the weight derivation unit 302 selects the combination closest to the combination of posture and strain of the current excavation attachment from the corresponding table, and the value of the lifting weight stored in association with the selected combination is the current lifting. Derived as weight. Distortion of the excavation attachment means distortion at one or more sites in the excavation attachment.

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

The "predetermined derivation condition" is a condition for determining the timing at which the weight derivation unit 302 derives the weight. For example, "the bucket 6 has floated" (first derivation condition) and "the dump operation has been completed". "(Second derivation condition) is included. The first derivation condition is that "the bucket 6 floats", that is, the bucket 6 is separated from the ground, because it can be estimated that when the bucket 6 floats, objects such as earth and sand are contained in the bucket 6. Is. The reason that "the dump operation is completed" is set as the second derivation condition is that it can be estimated that the bucket 6 is empty or the earth and sand that can be dropped have been removed when the dump operation is completed.

For example, when it is determined that the turning operation is performed after the excavation operation, the controller 30 determines that the first derivation condition is satisfied. This is because it can be estimated that the bucket 6 is floating in the air when the turning operation is performed. “After excavation operation” corresponds to after the operation of FIG. 3D, and the controller 30 is in a state after excavation operation from the posture of the excavation attachment and the distortion of the excavation attachment detected by the strain gauge attached to the upper and lower surfaces of the boom 4. It can be determined whether or not it is in. Specifically, the controller 30 determines that the first derivation condition is satisfied when it is determined that the turning operation lever is operated based on the output of the pressure sensor 29 after the excavation operation. The controller 30 may determine whether or not the turning operation has been performed based on the outputs of the two strain gauges attached to each of the side surfaces of the boom 4.

Alternatively, the controller 30 may determine that the first derivation condition is satisfied when it is determined that the boom 4 has risen above a predetermined height. This is because it can be estimated that the bucket 6 is floating in the air when the boom 4 rises above a predetermined height. Specifically, the controller 30 determines that the first derivation condition is satisfied when it is determined that the boom 4 has risen to a predetermined height or more based on the output of the boom angle sensor S1.

Alternatively, the controller 30 may determine that the first derivation condition is satisfied when it is determined that the bucket 6 is closed to a predetermined angle. This is because it can be estimated that the bucket 6 is floating in the air when the bucket 6 is closed to a predetermined angle. Specifically, the controller 30 determines that the first derivation condition is satisfied when it is determined that the bucket 6 is closed to a predetermined angle based on the output of the bucket angle sensor S3.

Further, the controller 30 determines that the second derivation condition is satisfied when it is determined that the turning operation is performed during the dump operation, for example. This is because it can be estimated that the dump operation is completed when the turning operation is performed. Specifically, the controller 30 determines that the second derivation condition is satisfied when it is determined that the turning operation lever is operated based on the output of the pressure sensor 29 during the dump operation.

Alternatively, the controller 30 may determine that the second derivation condition is satisfied when it is determined that the bucket 6 is opened to a predetermined angle after the first derivation condition is satisfied. This is because it can be estimated that the dump operation is completed when the bucket 6 is opened to a predetermined angle. Specifically, the controller 30 determines that the second derivation condition is satisfied when it is determined that the bucket 6 is opened to a predetermined angle based on the output of the bucket angle sensor S3.

When the weight derivation unit 302 derives the lifted weight, the weight derivation unit 302 may output a control command to at least one of the voice output device D2, the display device D3, the communication device D5, and the engine controller D6 according to the derivation result. For example, the weight deriving unit 302 may display information on the lifting weight on the display device D3, or may output audio through the audio output device D2. Further, the weight deriving unit 302 may wirelessly transmit information on the lifting weight to the outside via the communication device D5. Further, when the lifting weight is equal to or more than a predetermined value, the output of the engine 11 may be increased via the engine controller D6.

The attitude derivation unit 301 and the weight derivation unit 302 may be realized by an external control device outside the excavator. Like the controller 30, the external control device is an arithmetic processing unit including a CPU and an internal memory. In this case, the controller 30 wirelessly transmits the acquired information to the external control device through the communication device D5.

Next, with reference to FIG. 5, a process for the controller 30 to derive the lifted weight (hereinafter referred to as “weight derivation process”) will be described. FIG. 5 is a flowchart showing the flow of the weight derivation process. The controller 30 repeatedly executes this weight derivation process at a predetermined control cycle.

First, the weight derivation unit 302 of the controller 30 determines whether or not the bucket 6 has floated (step ST1). In this embodiment, the weight deriving unit 302 determines that the bucket 6 has floated when the turning operation is performed after the excavation operation. The weight deriving unit 302 may determine whether or not the bucket 6 has floated based on the pressure of the hydraulic oil in the hydraulic cylinder. Further, the weight deriving unit 302 determines whether or not the bucket 6 has floated after a predetermined time (for example, 2 seconds) has elapsed after the boom operating lever is operated in the raising direction and before the turning operating lever is operated. You may. This is because when the turning starts, the distortion due to the turning inertial force acts as noise.

When it is determined that the bucket 6 is not floating (NO in step ST1), the weight deriving unit 302 repeats the determination of whether or not the bucket 6 is floating until it is determined that the bucket 6 is floating.

When it is determined that the bucket 6 has floated (YES in step ST1), the weight deriving unit 302 acquires the posture of the excavation attachment and the strain of the boom 4 (step ST2). In this embodiment, the weight derivation unit 302 acquires the attitude of the excavation attachment derived by the attitude derivation unit 301 based on the output of the attitude sensor. Further, the strain of the boom 4 is acquired based on the output of the strain sensor S4.

After that, the weight deriving unit 302 derives the lifting weight (step ST3). In this embodiment, the weight of the earth and sand taken into the bucket 6 is lifted and derived as the weight by referring to the corresponding table stored in the storage device D4 using the posture of the excavation attachment and the distortion of the boom 4 as input keys. ..

With this configuration, the controller 30 can derive, for example, the loading weight (= lifting weight) of earth and sand loaded on the dump truck in each excavation / loading cycle. Further, by accumulating the loading weight for each cycle for each dump truck, the total loading weight of the earth and sand loaded on one dump truck can be derived as the work amount. Further, the controller 30 can derive the excavation weight per predetermined time as the work amount by accumulating the lifting weight for each cycle over a predetermined time. Therefore, the controller 30 can derive the amount of work by the excavation attachment with higher accuracy.

In this embodiment, the controller 30 derives the lifting weight based on the posture of the excavation attachment at the time when the bucket 6 is determined to be floating and the output of the strain sensor S4. However, the controller 30 may derive the lift weight based on the posture of the excavation attachment and the output of the strain sensor S4 at a plurality of time points after determining that the bucket 6 has floated in one cycle. In this case, the controller 30 uses the statistical values (average value, maximum value, minimum value, intermediate value, etc.) of the plurality of lift weights derived at the plurality of time points after determining that the bucket 6 is floated as the final lift weight. It may be output as.

Further, the controller 30 may continuously derive the lifting weight while continuously acquiring the posture of the excavation attachment and the distortion of the boom 4, regardless of whether or not the bucket 6 is floated. In this case as well, the controller 30 outputs the statistical value of the lifting weight at the time when the bucket 6 is determined to be floating or the statistical value of the lifting weight at a plurality of time points after the bucket 6 is determined to be floating as the final lifting weight. May be good.

Further, the controller 30 may determine the work contents such as excavation work, slope forming work, and floor digging work based on the change in the posture of the excavation attachment. In this case, the controller 30 may associate the identified work content with the work amount derived thereafter, and derive the work amount for each work content.

Next, with reference to FIGS. 6 and 7, the mounting position of the strain sensor S4 in the boom 4 will be described. 6 and 7 are both perspective views of the boom 4, showing the arrangement of strain sensors attached to the boom 4.

In the embodiment shown in FIG. 6, the strain gauge S40 as the strain sensor S4 has the boom cylinder boss 4a and the boom foot 4b so as to detect the strain of the boom 4 in the longitudinal direction of the boom 4 (the front-back direction of the excavation attachment). It is attached to the surface of the back side (+ Z side) of the boom 4 between them. Specifically, the strain gauge S40 is attached to the central portion of the dorsal surface of the boom 4. That is, they are arranged so as to cross the vertical center surface of the boom 4 (the surface including the line segment indicated by the alternate long and short dash line and vertically crossing the boom 4). However, the strain gauge S40 may be attached to the ventral (-Z side) surface of the boom 4, and may be attached to the dorsal or ventral surface of the boom 4 between the boom cylinder boss 4a and the boom top 4c. It may be attached. Further, it may be attached to a portion other than the central portion. The strain sensor S4 is attached so that the tensile compressive stress in the longitudinal direction of the boom 4 can be calculated even when the strain sensor S4 is attached to the back surface or the ventral surface.

With this arrangement, the strain sensor S4 can detect distortion due to expansion and contraction of the metal plates on the dorsal and ventral sides of the boom 4 when, for example, lifting earth and sand with an excavation attachment. In addition, strain due to tensile compressive stress due to the lifting load acting on the excavation attachment (boom 4) can be detected. Further, the strain sensor S4 may be attached to the inside of the dorsal side or the ventral side instead of the surface of the boom 4. This configuration can prevent damage to the strain sensor S4 even in a machine that performs excavation work such as a shovel.

In the embodiment shown in FIG. 7, the strain sensor S4 is composed of eight strain gauges S41 to S48. The broken line in FIG. 7 represents a hidden line. The strain gauge S41 and the strain gauge S42 are triaxial strain gauges. The strain gauges S43 to S48 are uniaxial strain gauges. The strain gauges S41 to S44 have surfaces on the dorsal side (+ Z side), ventral side (-Z side), left side (-Y side), and right side (+ Y side) of the boom 4 between the boom cylinder boss 4a and the boom foot 4b. It is attached to. The strain gauges S45 to S48 are located between the boom cylinder boss 4a and the boom top 4c on the dorsal side (+ Z side), ventral side (-Z side), left side (-Y side), and right side (+ Y side) of the boom 4. It is attached to the surface. The strain gauges S41, S42, S45, and S46 are arranged so as to cross the vertical center surface of the boom 4. The strain gauges S43, S44, S47, and S48 are attached to the central portion of the surface on the left or right side of the boom 4 so that the tensile compressive stress in the longitudinal direction of the boom 4 can be calculated. That is, they are arranged so as to cross the lateral center surface of the boom 4 (the surface including the line segment indicated by the alternate long and short dash line and crossing the boom 4). Further, the strain gauges S41 to S44 are arranged so as to cross the rear reference cross section R1 as a virtual plane indicated by the alternate long and short dash line, and the strain gauges S45 to S48 cross the front reference cross section R2 as a virtual plane indicated by the alternate long and short dash line. Have been placed. The rear reference cross section R1 and the front reference cross section R2 are perpendicular to each of the line segment represented by the alternate long and short dash line in FIG. 6 and the line segment represented by the alternate long and short dash line in FIG. 7.

Further, in the embodiment of FIG. 7, all eight strain gauges are attached to the surface of the boom 4, but the strain gauges may be less than 8 or 9 or more, other than the surface of the boom 4. It may be mounted in a position. For example, all strain gauges may be attached to the surface of the arm 5. Further, it may be dispersedly attached to the surface of the boom 4 and the surface of the arm 5. Further, the strain gauge may be attached to the inside of the working element such as the boom 4 and the arm 5 instead of the surface of the working element.

Since the embodiment of FIG. 7 uses eight strain gauges S41 to S48, the strain state of the excavation attachment can be detected with higher accuracy than the embodiment of FIG. 6 using one strain gauge. Therefore, even when the excavation attachment is in operation, the distorted state of the excavation attachment can be detected with high accuracy.

Next, another example of the weight derivation process will be described with reference to FIG. FIG. 8 is a flowchart showing another flow of the weight derivation process. The controller 30 repeatedly executes this weight derivation process at a predetermined control cycle.

First, the weight derivation unit 302 of the controller 30 determines whether or not the bucket 6 has floated (step ST1). In this embodiment, the weight deriving unit 302 determines that the bucket 6 has floated when the turning operation is performed after the excavation operation.

When it is determined that the bucket 6 is not floating (NO in step ST1), the weight deriving unit 302 repeats the determination of whether or not the bucket 6 is floating until it is determined that the bucket 6 is floating.

When it is determined that the bucket 6 has floated (YES in step ST1), the weight deriving unit 302 acquires the posture of the excavation attachment and the strain of the boom 4 (step ST2). In this embodiment, the weight derivation unit 302 acquires the attitude of the excavation attachment derived by the attitude derivation unit 301 based on the output of the attitude sensor. Further, the strain of the boom 4 is acquired based on the output of the strain sensor S4.

After that, the weight deriving unit 302 derives the lifting weight (weight before dumping) (step ST3). In this embodiment, the weight (dump) of earth and sand taken into the bucket 6 is lifted by referring to the corresponding table stored in the storage device D4 using the posture of the excavation attachment and the distortion of the boom 4 as input keys. Derived as (pre-weight).

After that, the weight derivation unit 302 determines whether or not the dump operation is completed (step ST4). In this embodiment, the weight derivation unit 302 determines that the dump operation is completed when the turning operation is performed during the dump operation. The weight deriving unit 302 may determine whether or not the dump operation is completed based on the pressure of the hydraulic oil in the hydraulic cylinder, the output of the attitude sensor, and the like. Further, the weight derivation unit 302 may detect the start of the dump operation when it is determined that the excavation attachment is facing the direction of the dump truck based on the image captured by the camera mounted on the excavator. Further, when it is determined that the bucket 6 is located directly above the dump truck based on the image, the start of the dump operation may be detected. Then, when it is determined that the bucket operation lever is operated in the opening direction based on the output of the pressure sensor 29, or when it is determined that the bucket 6 is opened based on the output of the bucket angle sensor, the dump operation is completed. It may be determined that it has been done.

When it is determined that the dump operation is not completed (NO in step ST4), the weight derivation unit 302 repeats the determination of whether or not the dump operation is completed until it is determined that the dump operation is completed.

When it is determined that the dump operation is completed (YES in step ST4), the weight deriving unit 302 acquires the posture of the excavation attachment and the strain of the boom 4 (step ST5). In this embodiment, the weight derivation unit 302 acquires the attitude of the excavation attachment derived by the attitude derivation unit 301 based on the output of the attitude sensor. Further, the strain of the boom 4 is acquired based on the output of the strain sensor S4.

After that, the weight deriving unit 302 derives the lifting weight (weight after dumping) (step ST6). In this embodiment, the weight of earth and sand remaining in the bucket 6 after the dump operation is lifted by referring to the corresponding table stored in the storage device D4 using the posture of the excavation attachment and the distortion of the boom 4 as input keys. Derived as weight (weight after dumping).

After that, the weight derivation unit 302 calculates the difference between the weight before the dump and the weight after the dump (step ST7). Then, the weight deriving unit 302 uses the difference as the loading weight of earth and sand loaded on the dump truck.

With this configuration, the controller 30 can derive, for example, the loading weight of earth and sand loaded on the dump truck in each excavation / loading cycle. In addition, the total weight of earth and sand loaded on the dump truck can be derived by accumulating the loading weight for each cycle. Further, since the difference between the weight before the dump and the weight after the dump is used as the loading weight, it is possible to prevent the weight of earth and sand stuck to the inside of the bucket 6 from being included in the loading weight when the dump operation is completed. ..

Next, with reference to FIG. 9, the torsional load acting on the excavation attachment will be described. FIG. 9 is a front view of the excavation attachment of the excavator 50 inclined by an angle θ with respect to the vertical axis. The arrow G1 pointing vertically downward indicates the gravity acting on the center of gravity of the bucket 6 and the earth and sand taken into the bucket 6. The arrow G1a pointing in the width direction of the bucket 6 indicates the lateral force which is a component in the width direction of the gravity.

Due to the presence of this lateral force, when the vehicle body of the excavator 50 is tilted, the arm 5 tries to rotate around the connecting portion between the arm 5 and the boom 4, and generates a torsional load T1 acting on the boom 4. ..

In the embodiment shown in FIG. 9, the strain gauge S40 as the strain sensor S4 is a 3-axis strain gauge and is attached to the inside of the boom 4. By using the 3-axis strain gauge, the controller 30 can detect strain in all directions of the X-axis direction, the Y-axis direction, and the Z-axis direction. Therefore, the controller 30 can calculate not only the bending stress based on the excavation load generated in each direction but also the shear stress based on the torsional load generated during eccentric excavation with the sensor attached to one place. Further, instead of using the 3-axis strain gauge, the strain gauge may be attached on the boom 4 in each direction (X-axis direction, Y-axis direction, Z-axis direction) as shown in FIG. ..

The torsional load T1 results in a particular pattern formed by the output of the strain gauge S40. The controller 30 can detect that the torsional load T1 is generated by detecting this specific pattern. As a result, the component life can be calculated accurately.

Further, a 3-axis strain gauge may be attached to the surface of the arm 5. In this case, since the controller 30 can calculate the shear stress due to the torsional load acting on the arm 5, the life of the arm 5 can be calculated accurately.

Next, with reference to FIG. 10, the communication network 100 to which the excavator 50 is connected will be described. FIG. 10 is a schematic diagram showing a communication network 100 to which the excavator 50 is connected. The communication network 100 is mainly composed of a shovel 50, a base station 21, a server 22, and a communication terminal 23. The communication terminal 23 includes a mobile communication terminal 23a, a fixed communication terminal 23b, and the like. The base station 21, the server 22, and the communication terminal 23 can each be connected to each other using a communication protocol such as an Internet protocol. The excavator 50, the base station 21, the server 22, and the communication terminal 23 may be one or a plurality of each. Further, the mobile communication terminal 23a includes a notebook computer, a mobile phone, a smartphone and the like.

The base station 21 is a fixed facility that receives information transmitted wirelessly by the excavator 50, and transmits / receives information to / from the excavator 50 through, for example, satellite communication, mobile phone communication, narrow area wireless communication, or the like.

The server 22 is a device that stores and manages information wirelessly transmitted by the shovel 50, and is, for example, a computer equipped with a CPU, a ROM, a RAM, an input / output interface, and the like. Specifically, the server 22 acquires and stores the information received by the base station 21 through the communication network 100, and manages the server 22 so that the operator (administrator) can refer to the stored information as needed.

Further, the server 22 makes various settings for the excavator 50 through the communication network 100. Specifically, the server 22 wirelessly transmits the values related to the various settings of the shovel 50 to the shovel 50, and changes the values related to the various settings stored in the controller 30 of the shovel 50.

Further, the server 22 transmits various information to the communication terminal 23 through the communication network 100. Specifically, the server 22 transmits information about the excavator 50 to the communication terminal 23 when a predetermined condition is satisfied or in response to a request from the communication terminal 23, and sends information about the excavator 50 to the communication terminal 23. Tell the operator of the communication terminal 23.

The communication terminal 23 is a device that can refer to the information stored in the server 22, and is, for example, a computer equipped with a CPU, a ROM, a RAM, an input / output interface, an input device, a display, a speaker, and the like. Specifically, the communication terminal 23 is connected to the server 22 through the communication network 100 so that the operator (administrator) can view the information about the excavator 50. Alternatively, the communication terminal 23 receives the information about the excavator 50 transmitted by the server 22 so that the operator (administrator) can view the received information.

In this embodiment, the server 22 manages information regarding the amount of work of the excavator 50 wirelessly transmitted by the excavator 50. Therefore, the operator (administrator) can receive and view the information regarding the work amount of the shovel 50 through the communication terminal 23 at an arbitrary timing.

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

1 ・ ・ ・ Lower traveling body 1A ・ ・ ・ Hydraulic motor for left side traveling 1B ・ ・ ・ Hydraulic motor for right side traveling 2 ・ ・ ・ Swing mechanism 2A ・ ・ ・ Hydraulic motor for turning 3 ・ ・ ・ Upper swivel body 4 ・ ・ ・Boom 4a ... Boom cylinder boss 4b ... Boom foot 4c ... Boom top 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 21 ・ ・ ・ Base station 22 ・ ・ ・ Server 23 ・ ・ ・ Communication terminal 23a ・ ・ ・ Mobile communication Terminal 23b ... Fixed communication terminal 25 ... Pilot line 26 ... Operating device 29 ... Pressure sensor 30 ... Controller 40L, 40R ... Center bypass pipeline 50 ... Excavator 100 ... Communication network 171 to 176 ... Flow control valve 301 ... Attitude lead-out unit 302 ... Weight lead-out unit D1 ... Input device D2 ... Voice output device D3 ... Display device D4 ... Storage device D5 ... Communication device D6 ... Engine controller S1 ... Boom angle sensor S2 ... Arm angle sensor S3 ... Bucket angle sensor S4 ... Distortion sensor S5 ... Body tilt sensor S40 to S48.・ ・ Strain gauge

Claims (2)

With the lower running body,
The upper swivel body mounted on the lower traveling body and the upper swivel body
An attachment that is attached to the upper swing body and includes a bucket ,
A posture sensor that detects the posture of the attachment, and
It is equipped with a control device that derives the loading weight for each excavation / loading cycle based on the differential pressure between the attitude sensor and the boom cylinder or the strain sensor attached to the attachment.
The control device is
Based on the image captured by the image pickup device, it is determined that the attachment is facing the direction of the dump truck.
After that, when the swivel operation is performed on the upper swivel body, the completion of the dump operation is determined, or the dump operation is completed based on the pressure sensor that detects the operation amount to the bucket cylinder that operates the bucket by the pressure. Judging,
When the dump operation is completed, the total load weight of the earth and sand loaded on one dump truck is derived by accumulating the load weight for each cycle.
Excavator. A shovel used for a shovel having a lower traveling body, an upper turning body mounted on the lower traveling body, an attachment attached to the upper turning body and including a bucket, and a posture sensor for detecting the posture of the attachment. It is a weight calculation device
It is equipped with a control device that derives the loading weight for each excavation / loading cycle based on the differential pressure between the attitude sensor and the boom cylinder or the strain sensor attached to the attachment.
The control device is
Based on the image captured by the image pickup device, it is determined that the attachment is facing the direction of the dump truck.
After that, when the swivel operation is performed on the upper swivel body, the completion of the dump operation is determined, or the dump operation is completed based on the pressure sensor that detects the operation amount to the bucket cylinder that operates the bucket by the pressure. Judging,
When the dump operation is completed, the total load weight of the earth and sand loaded on one dump truck is derived by accumulating the load weight for each cycle.
Excavator weight calculator.

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