Construction Machinery

Abstract

To suppress transmission of impact acting in a horizontal direction of a front to an acceleration sensor, and accurately detect acceleration in a longitudinal direction and a vertical direction of the front by the acceleration sensor.SOLUTION: A seat screw 15 is provided on a side face plate 14A of a boom 14 constituting a front 13 of a hydraulic shovel 1, and an acceleration sensor 22 is fixed to the seat screw 15 in a state of sandwiching a rubber plate 32 between the side face plate 14A of the boom 14 and the acceleration sensor 22. Thereby, even if impact acts in the horizontal direction of the front 13, the rubber plate 32 absorbs the impact, and transmission of excess impact to the acceleration sensor 22 can be suppressed. On the other hand, the acceleration sensor 22 is directly fixed to the seat screw 15 provided on the side face plate 14A of the boom 14, and accordingly accelerations in a longitudinal direction and a vertical direction when the boom 14 is moved can be accurately detected by the acceleration sensor 22.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to construction machines such as hydraulic excavators. [Background technology]

[0002] Generally, a hydraulic excavator, which is a typical example of a construction machine, comprises a self-propelled lower body and an upper rotating body that is rotatably mounted on the lower body. A work front having, for example, a bucket is rotatably provided on the front side of the upper rotating body, and this front is used for civil engineering work such as excavating soil and sand.

[0003] In recent years, information-based construction using IoT (Internet of Things) has been introduced into civil engineering work. Hydraulic excavators that support this information-based construction are equipped with a sensor that detects the posture of the front end, for example, the position of the tip (toe) of the excavation claws attached to the bucket. Then, the operation of the front end is controlled based on the position of the toe detected by the sensor, thereby performing semi-automatic operation construction so as not to deviate from the expected construction range (see Patent Document 1).

[0004] A sensor that detects the position of the tip of the bucket (front posture) mounted on a hydraulic excavator is usually attached to the front and is composed of, for example, an acceleration sensor that detects the acceleration when the front operates (rotates), an angle sensor that detects the rotation angle, etc. However, since the front of a hydraulic excavator is repeatedly subjected to shocks and vibrations when performing excavation work, etc., the shocks and vibrations are also transmitted to the sensor attached to the front.

[0005] In particular, the front of a hydraulic excavator is prone to side-to-side rattle (hereafter referred to as "side rattle") due to structural assembly tolerances and deterioration over time. As a result, the front receives large side-to-side shocks and vibrations during excavation work, and these large shocks and vibrations are transmitted to the acceleration sensor attached to the front, causing a large load on the acceleration sensor.

[0006] As a technology for absorbing vibrations transmitted to a sensor attached to the front of a hydraulic excavator, a configuration has been proposed in which vibration is absorbed by placing anti-vibration rubber between the front and the angle detector (see Patent Document 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-50541 [Patent Document 2] Japanese Utility Model Application Publication No. 59-014009 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in a hydraulic excavator equipped with an acceleration sensor to detect the position of the tip of the bucket, if an elastic body such as rubber is provided between the front and the acceleration sensor as in the conventional technology, the acceleration components of all directions (up and down, front and back, left and right) transmitted from the front to the acceleration sensor are absorbed and attenuated by the elastic body. This causes a discrepancy between the acceleration during the operation of the front and the acceleration detected by the acceleration sensor attached to the front via the elastic body. In particular, in a hydraulic excavator performing semi-automatic operation construction, the tip position is calculated using the acceleration detected by the acceleration sensor, and semi-automatic operation construction is performed based on the calculated tip position. Therefore, unless an accurate tip position is determined, there is a problem that the construction surface formed by semi-automatic operation construction using a hydraulic excavator differs from the expected construction surface.

[0009] An object of the present invention is to provide a construction machine in which the transmission of shocks and vibrations in the left and right directions of the front to the acceleration sensor is suppressed, and the acceleration in the front-to-back and up-down directions of the front can be accurately detected by the acceleration sensor. [Means for solving the problem]

[0010] The present invention relates to a construction machine including a self-propelled lower traveling body, an upper rotating body rotatably mounted on the lower traveling body, a front end rotatably attached to the upper rotating body, and an acceleration sensor attached to the front end. A sensor mounting member is provided on a side surface of the front end in a direction perpendicular to a direction in which the front end rotates relative to the upper rotating body, the acceleration sensor is fixed to the sensor mounting member, and an elastic body is disposed in a gap between the acceleration sensor fixed to the sensor mounting member and the side surface of the front end in a state where the acceleration sensor is sandwiched between the side surface of the front end and the side surface of the front end. The acceleration sensor is fixed to the sensor mounting member via a sensor board, the sensor board is fixed to the sensor mounting member with the elastic body sandwiched between the sensor board and the side surface of the front, the acceleration sensor is fastened to the sensor board using a sensor bolt, the elastic body is provided with a bolt engagement portion with which a tip end side of the sensor bolt protruding from the sensor board engages, and the elastic body is held between the side surface of the front and the sensor board by engaging the tip end side of the sensor bolt with the bolt engagement portion of the elastic body with the acceleration sensor fastened to the sensor board. It is characterized by the following. Effect of the Invention

[0011] According to the present invention, even if a left-right impact acts on the front, the impact is absorbed by the elastic body sandwiched between the side of the front and the acceleration sensor, thereby preventing excessive impact and vibration from being transmitted to the acceleration sensor. Meanwhile, since the acceleration sensor is fixed directly (rigidly) to the sensor mounting member provided on the side of the front without an elastic body, the acceleration sensor can accurately detect the front-rear and up-down acceleration of the front, which is important for calculating the toe position. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a left side view showing a hydraulic excavator according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view of the hydraulic excavator as viewed from above. [Diagram 3] FIG. 2 is an exploded perspective view showing a sheet screw, a sensor board, an acceleration sensor, a rubber plate, a sensor cover, etc., attached to a side plate of the boom. [Figure 4] 4 is a cross-sectional view of a boom side plate, a sheet screw, a sensor board, an acceleration sensor, a rubber plate, a sensor cover, etc., as viewed from the direction of arrows IV-IV in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An embodiment of a construction machine according to the present invention will be described in detail below with reference to Figures 1 to 4, taking as an example a case where the construction machine is applied to a hydraulic excavator. In the embodiment, the traveling direction of the hydraulic excavator is defined as the front-rear direction, and the direction perpendicular to the traveling direction is defined as the left-right direction.

[0014] A hydraulic excavator 1, which is a representative example of a construction machine, includes a self-propelled crawler-type lower traveling body 2, an upper rotating body 3 rotatably mounted on the lower traveling body 2, and a work front 13 (described below) whose base end is rotatably attached to the upper rotating body 3. The hydraulic excavator 1 travels on the lower traveling body 2 at a work site, and performs work such as excavating earth and sand by rotating the front 13 while rotating the upper rotating body 3.

[0015] The upper rotating body 3 is provided on the lower traveling body 2 so as to be able to rotate via a rotating device 4. The upper rotating body 3 includes a rotating frame 5, a counterweight 6, a cab 7, an exterior cover 8, a hydraulic oil tank 9, a fuel tank 10, etc.

[0016] The revolving frame 5 constitutes the base of the upper revolving body 3. As shown in Fig. 2, the revolving frame 5 includes a bottom plate 5A, a left vertical plate 5B and a right vertical plate 5C that are erected on the bottom plate 5A and extend in the front-rear direction at a predetermined interval in the left-right direction, and a left side frame 5D and a right side frame (not shown) that are disposed on both the left and right sides of the bottom plate 5A and extend in the front-rear direction. The base ends of a boom 14 and a boom cylinder 19, which will be described later, are rotatably attached to the front sides of the left vertical plate 5B and the right vertical plate 5C.

[0017] The counterweight 6 is provided on the rear end side of the revolving frame 5. The counterweight 6 is formed as a heavy weight whose rear surface is arc-shaped, and maintains a weight balance with the front 13.

[0018] The cab 7 is provided on the left front side of the revolving frame 5, located to the left of the left vertical plate 5B of the revolving frame 5. The cab 7 is formed in a box shape that defines a driver's compartment, and a driver's seat (not shown) for an operator to sit in is provided inside the cab 7. A travel lever and pedal device (not shown) for controlling the travel operation of the hydraulic excavator 1 is provided in front of the driver's seat, and operation lever devices (not shown) for controlling the revolving operation of the upper revolving body 3 and the operation of the front 13 are provided on both left and right sides of the driver's seat.

[0019] The exterior cover 8 is located in front of the counterweight 6 and is provided on the revolving frame 5. The exterior cover 8 includes a left rear side door 8A, a left front side door 8B, a right side door 8C, a top cover 8D, and an engine cover 8E, and is supported by a support member (not shown) provided on the revolving frame 5. A machine room is formed inside the exterior cover 8, and the onboard equipment (none of which are shown) such as an engine, a hydraulic pump, and a heat exchanger mounted on the revolving frame 5 are housed in this machine room.

[0020] The hydraulic oil tank 9 is provided on the revolving frame 5, located to the right of the right vertical plate 5C of the revolving frame 5. The hydraulic oil tank 9 stores hydraulic oil to be supplied to hydraulic actuators such as the travel motor of the lower traveling body 2, the rotation motor of the upper revolving body 3, and the cylinders 19, 20, 21 of the front 13. The fuel tank 10 is provided to the right of the right vertical plate 5C of the revolving frame 5, adjacent to the front side of the hydraulic oil tank 9. The fuel tank 10 stores fuel to be supplied to the engine.

[0021] The two antenna devices 11, 12 are provided on the upper rotating body 3, spaced apart in the left-right direction. One (left) antenna device 11 is erected on the left front side of the top cover 8D, and the other (right) antenna device 12 is erected on the right side of the top cover 8D. These two antenna devices 11, 12 are, for example, configured with GNSS antennas, and are connected to a controller (not shown) mounted on the upper rotating body 3.

[0022] The front end 13 for work is rotatably attached to the front side of the upper rotating body 3. The front end 13 is made up of a boom 14, an arm 16, a bucket 17, a bucket link 18, a boom cylinder 19, an arm cylinder 20, a bucket cylinder 21, etc., which will be described later. By extending and contracting each of the cylinders 19, 20, 21, the front end 13 rotates in the vertical direction or the front-rear direction relative to the upper rotating body 3, and performs work such as excavating earth and sand using the bucket 17.

[0023] The boom 14 of the front 13 is rotatably attached to the revolving frame 5 of the upper revolving body 3. Specifically, the base end of the boom 14 is rotatably connected to the front ends of the left vertical plate 5B and the right vertical plate 5C constituting the revolving frame 5 by using a connecting pin. The boom 14 is composed of left and right side plates 14A extending in the front-rear direction while maintaining a certain interval in the left-right direction, a top plate 14B connecting the upper ends of the left and right side plates 14A, and a bottom plate 14C facing the top plate 14B in the up-down direction and connecting the lower ends of the left and right side plates 14A. The boom 14 is formed as a box-shaped structure having a rectangular closed cross-sectional structure surrounded by the left and right side plates 14A, the top plate 14B, and the bottom plate 14C, and extends in the front-rear direction while bending gently in a mountain shape.

[0024] Here, the left and right side plates 14A of the boom 14 form side surfaces in a direction (left-right direction) perpendicular to the direction (front-back or up-down direction) in which the front 13 rotates relative to the upper rotating body 3, and an acceleration sensor 22, which will be described later, is attached to the left side plate 14A. As shown in Figures 3 and 4, two sheet screws 15 are provided on the left side plate 14A of the boom 14, spaced apart from each other in the front-rear direction.

[0025] Two sheet screws 15 as sensor mounting members are provided on the left side plate 14A of the boom 14, spaced apart from each other in the front and rear. The front and rear sheet screws 15 are formed, for example, using rectangular parallelepiped steel bars (square steel), and are fixed to the surface of the side plate 14A by means of welding or the like, while being arranged parallel to each other and spaced apart from each other in the longitudinal direction of the boom 14. As a result, the front and rear sheet screws 15 are arranged parallel to each other at a constant interval in the front and rear direction, and protrude from the surface of the side plate 14A. At both ends in the longitudinal direction of the sheet screw 15, bolt holes (female thread holes) 15A are formed that penetrate in the plate thickness direction. An acceleration sensor 22 is fixed to the front and rear sheet screws 15 via a sensor board 26 described later.

[0026] The arm 16 is rotatably attached to the tip of the boom 14. Like the boom 14, the arm 16 is formed as a box-shaped structure having a rectangular closed cross-sectional structure surrounded by left and right side plates 16A, an upper plate 16B, and a lower plate 16C, and extends in the front-rear direction. Here, the left and right side plates 16A of the arm 16 form side surfaces in a direction (left-right direction) perpendicular to the direction in which the front 13 rotates relative to the upper rotating body 3 (front-rear direction or up-down direction), and an acceleration sensor 23, which will be described later, is attached to the left side plate 16A.

[0027] Bucket 17 is rotatably attached to the tip of arm 16. Bucket 17 has bucket body 17A, the interior of which serves as a soil storage section, and a plurality of excavation claws 17B attached to the cutting edge of bucket body 17A. Bucket 17 excavates soil with excavation claws 17B by rotating at the tip of arm 16, and stores the excavated soil inside bucket body 17A (soil storage section).

[0028] Bucket link 18 is provided between the tip of arm 16 and bucket 17. Bucket link 18 is composed of rear link 18A having one end connected to the tip of arm 16, and front link 18B having one end connected to the other end of rear link 18A and the other end connected to bucket 17. Here, rear link 18A and front link 18B constituting bucket link 18 each have left and right side surfaces 18A1, 18B1 constituting side surfaces in a direction (left and right direction) perpendicular to the direction in which front 13 rotates with respect to upper rotating body 3 (front-rear direction or up-down direction), and an acceleration sensor 24 described later is attached to side surface 18A1 of rear link 18A.

[0029] The boom cylinders 19 are provided between the left vertical plate 5B and the right vertical plate 5C of the revolving frame 5 and the boom 14. Two boom cylinders 19 are provided on each side of the boom 14. By extending and retracting these two boom cylinders 19, the boom 14 rotates in the front-to-rear and up-down directions relative to the upper revolving body 3 (revolving frame 5).

[0030] The arm cylinder 20 is provided between the boom 14 and the arm 16. By extending and retracting the arm cylinder 20, the arm 16 rotates in the front-rear direction or up-down direction relative to the boom 14. The bucket cylinder 21 is provided between the arm 16 and the bucket link 18 (the connection between the rear link 18A and the front link 18B). By extending and retracting the bucket cylinder 21, the bucket 17 rotates in the front-rear direction or up-down direction relative to the arm 16.

[0031] An acceleration sensor 22 that detects the acceleration of the boom 14 is attached to the left side plate 14A of the boom 14 that constitutes the front 13. An acceleration sensor 23 that detects the acceleration of the arm 16 is attached to the left side plate 16A of the arm 16. In addition, an acceleration sensor 24 that detects the acceleration of the bucket 17 that is linked to the operation of the bucket link 18 is attached to the left side surface 18A1 of the rear link 18A that constitutes the bucket link 18. In addition, a vehicle body inclination angle sensor 25 that detects the inclination of the hydraulic excavator 1 at the work site is provided on the upper rotating body 3.

[0032] These acceleration sensors 22, 23, 24 and vehicle body inclination angle sensor 25 detect the attitude of the front 13 working on the ground, i.e., the position of the tip (toe) of the digging claw 17B provided on the bucket 17, when semi-automatic operation construction is performed using the hydraulic excavator 1, and are connected to a controller (not shown) mounted on the upper rotating body 3. The controller calculates the position of the toe of the digging claw 17B based on the acceleration of the boom 14, arm 16, and bucket 17 detected by the acceleration sensors 22, 23, 24 and the inclination of the hydraulic excavator 1 (upper rotating body 3) detected by the vehicle body inclination angle sensor 25, and controls the operation of the front 13 while, for example, comparing three-dimensional data of the ground to be worked with the calculated position information of the toe of the digging claw 17B.

[0033] Here, when excavation work is performed using the front end 13, a large impact acts on the excavation claws 17B of the bucket 17. Since the front end 13 has lateral play due to assembly tolerances and deterioration over time, it is necessary to suppress excessive impact and vibration in the left and right directions that is transmitted to the acceleration sensors 22, 23, and 24 due to the large impact acting on the excavation claws 17B. On the other hand, the acceleration when the boom 14, arm 16, and bucket 17 of the front end 13 move in the up and down directions and in the up and down directions during excavation work needs to be accurately detected by the acceleration sensors 22, 23, and 24 in order to calculate an accurate toe position.

[0034] For this reason, in this embodiment, the mounting structure of the acceleration sensors 22, 23, and 24 on the front 13 is devised to prevent excessive shock and vibration from being transmitted to the acceleration sensors 22, 23, and 24. Since these acceleration sensors 22, 23, and 24 are mounted on the front 13 by the same mounting structure, the mounting structure of the acceleration sensor 22 on the boom 14 will be described below, and a description of the mounting structures of the acceleration sensors 23 and 24 will be omitted.

[0035] 3 and 4 show the mounting structure of the acceleration sensor 22 on the left side plate 14A of the boom 14. The acceleration sensor 22 is formed in the shape of a rectangular parallelepiped block, and a front mounting flange 22A and a rear mounting flange 22B are provided protruding in the front-to-rear direction on the bottom side of the acceleration sensor 22. The front mounting flange 22A is provided with one bolt insertion hole 22C penetrating in the plate thickness direction, and the rear mounting flange 22B is provided with two bolt insertion holes 22D penetrating in the plate thickness direction.

[0036] The sensor board 26 is attached to the bottom of the acceleration sensor 22. The sensor board 26 is formed in the shape of a rectangular flat plate extending in the front-rear direction using a steel plate material or the like, and has a width dimension equal to the length dimension of the sheet screw 15 fixed to the side plate 14A of the boom 14, and a length dimension spanning the front and rear sheet screws 15. The sensor board 26 has a length dimension greater than that of the acceleration sensor 22, and a width dimension equal to that of the acceleration sensor 22.

[0037] The sensor board 26 has bolt insertion holes 26A, two on each end in the length direction (four in total), and three bolt holes (female thread holes) 26B arranged inside the four bolt insertion holes 26A, which penetrate the board in the plate thickness direction. The four bolt insertion holes 26A correspond to the bolt holes 15A, two on each of the front and rear seat screws 15. The three bolt holes 26B correspond to the bolt insertion holes 22C in the front mounting flange 22A of the acceleration sensor 22 and the bolt insertion holes 22D in the rear mounting flange 22B.

[0038] Sensor bolts 27 are inserted through bolt insertion holes 22C provided in the front mounting flange 22A of the acceleration sensor 22 and through bolt insertion holes 22D provided in the rear mounting flange 22B. The acceleration sensor 22 is fastened to the sensor board 26 by screwing these three sensor bolts 27 into bolt holes 26B of the sensor board 26. The length of the sensor bolts 27 is set so that the tip sides of the sensor bolts 27 protrude from the sensor board 26 toward the side plate 14A of the boom 14 when the acceleration sensor 22 is fastened to the sensor board 26.

[0039] The sensor cover 28 is attached to the sensor board 26 in a state where it covers the acceleration sensor 22. The sensor cover 28 is composed of a peripheral wall plate 28A that is a rectangular frame-like plate that is slightly larger than the sensor board 26, and an upper plate 28B that closes the upper end of the peripheral wall plate 28A. The upper plate 28B is provided with two bolt insertion holes 28C located at diagonal corners thereof, and these two bolt insertion holes 28C correspond to the two bolt insertion holes 26A located at diagonal corners of the sensor board 26.

[0040] Long bolts 29 are inserted into bolt insertion holes 28C of sensor cover 28, and cylindrical spacers 30 are inserted into the two long bolts 29 inside sensor cover 28. Spacer 30 is disposed between sensor board 26 and upper plate 28B of sensor cover 28, and secures a space between them to accommodate acceleration sensor 22. When sensor board 26 is fixed to sheet screw 15, sensor cover 28 is fixed (co-fastened) to sheet screw 15 together with sensor board 26.

[0041] The two long bolts 29 inserted through the bolt insertion holes 28C of the sensor cover 28 and the spacer 30 are inserted through two bolt insertion holes 26A located at one diagonal corner of the sensor board 26. These two long bolts 29 are screwed through the spacer 30 into one of two bolt holes 15A provided in the front and rear sheet screws 15. Furthermore, bolts 31 shorter than the long bolts 29 are inserted through the two bolt insertion holes 26A located at the other diagonal corner of the sensor board 26. These two bolts 31 are screwed into the other of the two bolt holes 15A provided in the front and rear sheet screws 15.

[0042] In this way, the sensor board 26 is fixed in a state in which it is stretched across the front and rear (two) sheet screws 15, so that the distance between the side plate 14A of the boom 14 and the sensor board 26 is equalized. The acceleration sensor 22 is fixed to the sheet screws 15 via the sensor board 26, and a rubber plate 32, which will be described later, is sandwiched between the side plate 14A of the boom 14 and the sensor board 26. In addition, the sensor cover 28 is fixed to the sheet screws 15 together with the sensor board 26.

[0043] The rubber plate 32 as an elastic body is provided in a space between the side plate 14A of the boom 14 and the acceleration sensor 22 so as to be elastically deformable. The rubber plate 32 is formed in a rectangular plate shape using a rubber material having excellent weather resistance, aging resistance, oil resistance, etc., such as chloroprene rubber (CR). The rubber plate 32 has a length dimension smaller than the distance between the front and rear sheet screws 15, a width dimension equal to the length dimension of the sheet screws 15, and a thickness dimension slightly larger than the protruding height of the sheet screws 15 from the side plate 14A of the boom 14.

[0044] Specifically, the acceleration sensor 22 has a sensor board 26 fixed thereto, and the sensor board 26 is hung across the front and rear sheet screws 15, with a rubber plate 32 sandwiched between the sensor board 26 and the side plate 14A of the boom 14. In this case, the distance between the side plate 14A of the boom 14 and the sensor board 26 is equalized, and the rubber plate 32 is evenly crushed between the side plate 14A and the sensor board 26, so that a constant initial load is applied to the rubber plate 32 sandwiched between them in the plate thickness direction. In addition, the acceleration sensor 22 and the rubber plate 32 are arranged so as to overlap each other in a direction perpendicular to the direction in which the front 13 rotates relative to the upper rotating body 3. This allows the rubber plate 32 to absorb vibrations transmitted to the acceleration sensor 22 due to impacts in the left and right directions acting on the boom 14.

[0045] In this way, even if an impact acts on the front 13 in the left-right direction during excavation work, the impact is absorbed by elastic deformation of the rubber plate 32 sandwiched between the side plate 14A of the boom 14 and the acceleration sensor 22, making it possible to prevent excessive impact and vibration from being transmitted to the acceleration sensor 22. Meanwhile, the sensor board 26 on which the acceleration sensor 22 is mounted is fixed directly (rigidly) to the front and rear sheet screws 15 provided on the side plate 14A of the boom 14 without the intervention of an elastic body such as the rubber plate 32. This makes it possible to accurately detect the acceleration when the boom 14 moves in the front-rear and up-down directions during excavation work by the acceleration sensor 22 integrated with the boom 14 without damping or absorbing the acceleration by an elastic body.

[0046] The rubber plate 32 is also provided with two bolt engagement holes 32A as bolt engagement portions. Two of the three sensor bolts 27 that fasten the acceleration sensor 22 to the sensor board 26 are inserted (engaged) into these two bolt engagement holes 32A. That is, the tip sides of the two sensor bolts 27 inserted into the bolt insertion holes 22D of the rear mounting flange 22B of the acceleration sensor 22 protrude from the sensor board 26 and are inserted into the bolt engagement hole 32A of the rubber plate 32. On the other hand, the tip side of the one sensor bolt 27 inserted into the bolt insertion hole 22C of the front mounting flange 22A of the acceleration sensor 22 protrudes from the sensor board 26 to a position adjacent to the front end 32B of the rubber plate 32.

[0047] In this way, two of the three sensor bolts 27 that fasten the acceleration sensor 22 to the sensor board 26 are inserted into the bolt engagement holes 32A of the rubber plate 32, and the remaining one protrudes to a position adjacent to the front end 32B of the rubber plate 32. As a result, the rubber plate 32 is held between the side plate 14A and the sensor board 26 by using the sensor bolts 27.

[0048] As described above, the acceleration sensor 22 that detects the acceleration of the boom 14 is fixed via the sensor board 26 to the sheet screw 15 that protrudes from the side plate 14A of the boom 14, with the rubber plate 32 sandwiched between the sensor board 26 and the side plate 14A of the boom 14. Meanwhile, the acceleration sensor 23 that detects the acceleration of the arm 16 is also attached to the side plate 16A of the arm 16 by a mounting structure similar to that of the acceleration sensor 22, and the acceleration sensor 24 that detects the acceleration of the bucket 17 is also attached to the side surface 18A1 of the bucket link 18 (rear link 18A) by a mounting structure similar to that of the acceleration sensor 22.

[0049] The hydraulic excavator 1 according to this embodiment has the above-mentioned configuration, and when performing excavation work using the hydraulic excavator 1, the operator gets into the cab 7 and operates the travel lever and pedal device (not shown) to drive the hydraulic excavator 1 to a desired work site. The operator then operates the operating lever device (not shown) to rotate the upper rotating body 3 while rotating the boom 14, arm 16, and bucket 17 of the front 13, and perform excavation work of earth and sand.

[0050] When semi-automatic operation construction is performed using the hydraulic excavator 1, a controller (not shown) calculates the position of the toe of the excavation claw 17B provided on the bucket 17 based on the acceleration of the boom 14, arm 16, and bucket 17 detected by the acceleration sensors 22, 23, and 24, and the inclination of the hydraulic excavator 1 detected by the vehicle body inclination angle sensor 25. The controller then controls the operation of the front 13 while comparing the calculated position information of the toe of the excavation claw 17B with three-dimensional data of the ground to be worked on. In this way, semi-automatic operation construction is performed using the hydraulic excavator 1.

[0051] During excavation work using the front end 13, a large impact acts on the excavation claws 17B of the bucket 17. Since the front end 13 has lateral play due to assembly tolerances and deterioration over time, it is necessary to suppress excessive impacts and vibrations in the left and right directions that are transmitted to the acceleration sensors 22, 23, and 24 due to the large impact acting on the excavation claws 17B.

[0052] In contrast, according to this embodiment, a rubber plate 32 is sandwiched between the side plate 14A of the boom 14 and the sensor board 26 with the sensor board 26 attached to the acceleration sensor 22 fixed to the sheet screw 15. As a result, even if a left-right impact acts on the excavation claw 17B of the bucket 17 during excavation work, the rubber plate 32 sandwiched between the side plate 14A of the boom 14 and the acceleration sensor 22 elastically deforms, absorbing left-right vibrations caused by lateral play resulting from assembly tolerances and aging deterioration of the front 13. As a result, it is possible to suppress the transmission of excessive impacts and vibrations to the acceleration sensor 22, and the durability of the acceleration sensor 22 can be improved. Also, as with the acceleration sensor 22, the acceleration sensors 23 and 24 are also able to suppress the transmission of excessive impacts and vibrations to the acceleration sensors 23 and 24 because the elastic deformation of the rubber plate absorbs the impacts and vibrations acting in the left-right direction of the front 13.

[0053] Moreover, according to this embodiment, the sensor board 26 on which the acceleration sensor 22 is attached is fixed directly (rigidly) to the front and rear sheet screws 15 protruding from the side plate 14A of the boom 14 without any elastic body such as a rubber plate 32 being interposed therebetween. As a result, the acceleration in the front-rear direction and the up-down direction when the boom 14 moves can be accurately detected by the acceleration sensor 22 integrated with the boom 14. Similarly to the acceleration sensor 22, the acceleration sensors 23 and 24 are also directly fixed to the side plate 16A of the arm 16 and the side surface 18A1 of the bucket link 18 (rear link 18A), respectively, without any elastic body being interposed therebetween. As a result, the acceleration in the front-rear direction and the up-down direction when the arm 16 and the bucket 17 move can be accurately detected.

[0054] Thus, the hydraulic excavator 1 according to this embodiment comprises a self-propelled lower running body 2, an upper rotating body 3 rotatably mounted on the lower running body 2, a front 13 whose base end is rotatably attached to the upper rotating body 3, and an acceleration sensor 22 provided on the front 13. A sheet screw 15 is provided on a side plate 14A of the boom 14 of the front 13 that is perpendicular to the direction in which the front 13 rotates relative to the upper rotating body 3, and the acceleration sensor 22 is fixed to the sheet screw 15. A rubber plate 32 is arranged in the gap between the acceleration sensor 22 fixed to the sheet screw 15 and the side plate 14A of the boom 14, sandwiched between the acceleration sensor 22 and the side plate 14A of the boom 14.

[0055] With this configuration, even if an impact acts on the front 13 in the left-right direction, the impact is absorbed by the rubber plate 32 sandwiched between the side plate 14A of the boom 14 and the acceleration sensor 22, thereby preventing excessive impact and vibration from being transmitted to the acceleration sensor 22. Meanwhile, since the acceleration sensor 22 is directly fixed to the sheet screw 15 provided on the side plate 14A of the boom 14 without using the rubber plate 32, the acceleration sensor 22 can accurately detect the acceleration in the front-rear and up-down directions when the boom 14 moves.

[0056] In this embodiment, a sensor board 26 on which the acceleration sensor 22 is attached is further provided, and the acceleration sensor 22 is fixed to the sheet screw 15 via the sensor board 26. According to this configuration, by attaching the acceleration sensor 22 to the sensor board 26, the acceleration sensor 22 can be reliably fixed to the sheet screw 15 regardless of the shape of the acceleration sensor 22.

[0057] In this embodiment, two sheet screws 15 are provided at a distance from each other on the side plate 14A of the boom 14, and the acceleration sensor 22 is fixed in a state of being stretched across the two sheet screws 15. With this configuration, the distance between the side plate 14A of the boom 14 and the acceleration sensor 22 can be made equal, and a constant initial load can be applied to the elastic body sandwiched between them.

[0058] In this embodiment, the acceleration sensor 22 and the rubber plate 32 are arranged so as to overlap each other in a direction perpendicular to the direction in which the front 13 rotates relative to the upper rotating body 3. According to this configuration, the vibration transmitted to the acceleration sensor 22 due to a left-right impact acting on the boom 14 can be absorbed by the entire rubber plate 32, so that the rubber plate 32 can reliably prevent excessive impact and vibration from being transmitted to the acceleration sensor 22.

[0059] In the embodiment, the sensor board 26 is fixed to the sheet screw 15 with a rubber plate 32 sandwiched between the sensor board 26 and the side plate 14A of the boom 14, the acceleration sensor 22 is fastened to the sensor board 26 by using a sensor bolt 27, the rubber plate 32 is provided with a bolt engagement hole 32A with which the tip side of the sensor bolt 27 protruding from the sensor board 26 engages, and the rubber plate 32 is held between the side plate 14A of the boom 14 and the sensor board 26 by engaging the tip side of the sensor bolt 27 with the bolt engagement hole 32A of the rubber plate 32 with the acceleration sensor 22 fastened to the sensor board 26. According to this configuration, the rubber plate 32 can be held between the side plate 14A and the sensor board 26 by utilizing the sensor bolt 27. As a result, the workability when arranging the rubber plate 32 between the side plate 14A of the boom 14 and the sensor board 26 can be improved.

[0060] In the embodiment, the acceleration sensor 22 is fastened to the sensor board 26, and the sensor board 26 is attached to the front and rear sheet screws 15 protruding from the side plate 14A of the boom 14. However, the present invention is not limited to this, and for example, the acceleration sensor 22 may be directly attached to the sheet screws 15 protruding from the side plate 14A of the boom 14, and a rubber plate 32 may be sandwiched between the acceleration sensor 22 and the side plate 14A.

[0061] Also, in the embodiment, the acceleration sensor 24 that detects the acceleration of the bucket 17 is attached to the side surface 18A1 of the rear link 18A that constitutes the bucket link 18. However, the present invention is not limited to this, and the acceleration sensor 24 may be attached to the side surface 18B1 of the front link 18B, for example. [Explanation of symbols]

[0062] 1. Hydraulic excavator 2 Undercarriage 3. Upper rotating body 13. Front Desk 14. Boom 14A,16A Side plate (side) 15 Sheet screw (sensor mounting part) 16 Arm 18 Bucket Link 18A1 Side 22, 23, 24 Acceleration sensor 26 Sensor board 27 Sensor bolt 32 Rubber plate (elastic body) 32A Bolt engagement hole (bolt engagement part)

Claims

1. A construction machine including a self-propelled lower traveling body, an upper rotating body rotatably mounted on the lower traveling body, a front end rotatably attached to the upper rotating body at a base end, and an acceleration sensor attached to the front end, A sensor mounting member is provided on a side surface of the front end in a direction perpendicular to a direction in which the front end rotates relative to the upper rotating body, the sensor mounting member protruding from the side surface, The acceleration sensor is fixed to the sensor mounting member, an elastic body disposed in a gap between the acceleration sensor fixed to the sensor mounting member and the side surface of the front end so as to be sandwiched between the acceleration sensor and the side surface of the front end, the acceleration sensor is fixed to the sensor mounting member via a sensor substrate, the sensor board is fixed to the sensor mounting member with the elastic body sandwiched between the sensor board and the side surface of the front, the acceleration sensor is fastened to the sensor board using a sensor bolt, the elastic body is provided with a bolt engagement portion with which a tip end side of the sensor bolt protruding from the sensor board is engaged, a tip end of the sensor bolt engaging with the bolt engagement portion of the elastic body while the acceleration sensor is fastened to the sensor board, thereby holding the elastic body between the side of the front and the sensor board.

2. The sensor mounting member is provided in two pieces on the side surface of the front panel with a space between them, 2. The construction machine according to claim 1, wherein the acceleration sensor is fixed in a state of being spanned between the two sensor mounting members.

3. 2. The construction machine according to claim 1, wherein the acceleration sensor and the elastic body are arranged so as to overlap each other in a direction perpendicular to a direction in which the front part rotates relative to the upper rotating body.

Images