Work machine and method for calculating inclination degree of work machine

Abstract

To provide a work machine capable of accurately determining a degree of inclination with respect to a horizontal face of the work machine requiring durability.SOLUTION: A work machine comprises a vehicle body, a work device, and a controller 100. The vehicle body includes a frame to which the work device is attached, a driver cab, and a plurality of liquid enclosing mounts 34 disposed at different positions of the frame and supporting the driver cab. At least one of the plurality of liquid enclosing mounts 34 has a sensor 349 detecting liquid pressure of enclosed liquid. The controller calculates a degree of inclination of the work machine with respect to a horizontal face based on detection results by the sensor 349.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present disclosure relates to a work machine and a method for calculating an inclination degree of a work machine. [Background technology]

[0002] Conventionally, a working machine equipped with a working implement is known. For example, Japanese Patent Laid-Open Publication No. 7-207711 (Patent Document 1) discloses a hydraulic excavator equipped with an anti-toppling device as such a working machine. Detection signals from a boom angle detection means, an arm angle detection means, a rotation angle detection means, and an inclination angle detection means are input to a controller of the anti-toppling device. The controller issues an alarm, stops the operation of the boom and arm, and stops the rotation operation before there is a risk of tipping, in response to the rotational movement of the boom and arm and the rotational movement of the upper rotating body. As the inclination angle detection means, an inclination angle sensor that detects the inclination angle of the machine body relative to the horizontal plane is used. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-207711 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, an inclination angle of a horizontal plane of the body of a work machine is detected by an inclination angle sensor. Therefore, the inclination angle sensor in Patent Document 1 is required to have high accuracy and durability.

[0005] The present disclosure provides a work machine and a method for calculating the degree of inclination of a work machine that is required to have durability and that is capable of accurately determining the degree of inclination of the work machine with respect to a horizontal plane. [Means for solving the problem]

[0006] According to an aspect of the present disclosure, a work machine includes a vehicle body, a work implement, and a controller. The vehicle body includes a frame to which the work implement is attached, a cab, and a plurality of fluid-sealed mounts that are installed at different positions on the frame and support the cab. At least one of the plurality of fluid-sealed mounts has a sensor that detects the hydraulic pressure of the sealed liquid. The controller calculates the degree of inclination of the work machine with respect to a horizontal plane based on a result of detection by the sensor.

[0007] According to another aspect of the present disclosure, a body of a work machine includes a frame to which a work implement is attached, a cab, and a plurality of hydraulic mounts that are installed at different positions on the frame and support the cab. A method for calculating an inclination degree of a work machine includes a step of detecting a hydraulic pressure of a liquid sealed in at least one of the plurality of hydraulic mounts, and a step of a controller of the work machine calculating an inclination degree of the work machine relative to a horizontal plane based on a result of the detection. Effect of the Invention

[0008] According to the present disclosure, it is possible to accurately determine the degree of inclination of a work machine with respect to a horizontal plane. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a side view showing a schematic configuration of a hydraulic excavator. [Diagram 2] FIG. 2 is a diagram for explaining the configuration of a rotating body. [Diagram 3] FIG. 2 is a diagram showing the main parts of a fluid-filled mount. [Figure 4] FIG. 13 is a diagram showing the characteristics of a hydraulic mount. [Figure 5A] FIG. 2 is a diagram illustrating a state in which the hydraulic excavator is positioned on a horizontal plane. [Figure 5B] FIG. 2 is a diagram illustrating a state in which the hydraulic excavator is located on a slope. [Figure 6] FIG. 1 is a diagram for explaining changes in the amount of deflection (amount of displacement) of three hydraulic mounts. [Figure 7] FIG. 1 is a diagram for explaining tipping over of a hydraulic excavator. [Figure 8] FIG. 2 is a block diagram for explaining a hardware configuration of a hydraulic excavator and a functional configuration of a controller of the hydraulic excavator. [Figure 9] FIG. 4 is a flow chart for explaining a process flow of a controller. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described with reference to the drawings. It is intended from the beginning that the configurations in the embodiments will be used in appropriate combination. In addition, there may be cases where some of the components are not used.

[0011] In the following description, a hydraulic excavator is used as an example of a work machine. However, the work machine is not limited to a hydraulic excavator, and is not particularly limited as long as it is a work machine having a working implement. Furthermore, in the following description, "upper," "lower," "front," "rear," "left," and "right" are terms based on an operator seated in the driver's seat.

[0012] FIG. 1 is a side view showing a schematic configuration of a hydraulic excavator.

[0013] 1, the hydraulic excavator 1 includes a work machine 2 and a vehicle body 3. The vehicle body 3 includes a traveling body 31, a swing circle 32, a rotating body 33, and a hydraulic motor 35.

[0014] The traveling body 31 has a pair of left and right track belt devices 311. Each of the pair of left and right track belt devices 311 has tracks. The pair of left and right tracks are rotationally driven to cause the hydraulic excavator 1 to self-propel.

[0015] The swing circle 32 is connected to a hydraulic motor 35. The swing circle 32 is rotated by the rotational drive of the hydraulic motor 35.

[0016] The rotating body 33 is installed on the running body 31 via the swing circle 32. The rotating body 33 rotates with respect to the running body 31 as the swing circle 32 rotates.

[0017] The rotating body 33 has a frame 331 to which the work machine 2 is attached, a cab 332, and a controller (see FIG. 8) that controls the operation of the hydraulic excavator 1. The cab 332 is disposed, for example, on the front left side (vehicle front side) of the rotating body 33. The hydraulic motor 35 is driven by hydraulic oil supplied from a hydraulic source.

[0018] The work machine 2 is pivotally supported on the front side of the rotating body 33, for example, on the right side of the operator's cab 332. The work machine 2 has a boom 21, an arm 22, a bucket 23, a boom cylinder 211, an arm cylinder 221, a bucket cylinder 231, and the like.

[0019] The boom 21 is attached to a rotating body 33. A base end of the boom 21 is rotatably connected to the rotating body 33 by a boom foot pin (not shown).

[0020] The arm 22 is attached to the tip of the boom 21. The base end of the arm 22 is rotatably connected to the tip of the boom 21 by a boom tip pin 242.

[0021] The bucket 23 is attached to the tip of the arm 22. The bucket 23 is rotatably connected to the tip of the arm 22 by an arm tip pin 243.

[0022] The boom 21 can be driven by a boom cylinder 211. The boom cylinder 211 is driven by hydraulic oil supplied from a hydraulic source (a hydraulic pump and an oil tank, not shown). This drive allows the boom 21 to rotate in the vertical direction relative to the rotating body 33 around a boom foot pin (not shown).

[0023] The arm 22 can be driven by an arm cylinder 221. By this drive, the arm 22 can be rotated in the vertical direction relative to the boom 21 around a boom tip pin 242.

[0024] The bucket 23 can be driven by a bucket cylinder 231. This drive allows the bucket 23 to rotate vertically relative to the arm 22 around the arm tip pin 243. In this manner, the work machine 2 can be driven.

[0025] FIG. 2 is a diagram for explaining the configuration of the rotating body 33. As shown in FIG.

[0026] 2, as described above, the rotating bed 33 includes the frame 331 and the cab 332. The rotating bed 33 further includes a plurality of hydraulic mounts 34a, 34b, .... The hydraulic mounts are also called "viscous mounts" or "anti-vibration mounts."

[0027] The frame 331 includes a frame body 331a and a beam 331b extending in the left-right direction.

[0028] The cab 332 has a front portion 332a, a rear portion 332b, a side portion 332c (only the left side is shown), and an upper portion 332d. The cab 332 is surrounded by the portions 332a, 332b, 332c, and 332d. A floor plate bracket 332e is provided on the lower end side of the cab 332. A floor plate 332f forming the bottom of the cab 332 is attached to the floor plate bracket 332e.

[0029] The plurality of hydraulic mounts 34a, 34b, ... are installed at different positions on the frame 331 and support the operator's cab 332. In this example, the rotating bed 33 is provided with four hydraulic mounts 34a, 34b, 34c, 34d (FIGS. 6 and 8).

[0030] The hydraulic mount 34a is mounted on the front left side of the frame 331. The hydraulic mount 34b is mounted on the rear left side of the frame 331. Similarly, the hydraulic mounts 34c and 34d (FIG. 6) are mounted on the rear right side of the frame 331 and the front right side of the frame 331, respectively.

[0031] The fluid-filled mounts 34a and 34d are disposed at a distance from each other between the frame 331a and a floor plate 332f of the driver's cab 332. The fluid-filled mounts 34b and 34c are disposed at a distance from each other between the beam 331b and the floor plate 332f.

[0032] In this manner, the four hydraulic mounts 34a to 34d are installed at the four corners of the lower part of the cab 332. The hydraulic mounts 34a to 34d can suppress the vibration of the frame 331 from being transmitted to the cab 332.

[0033] FIG. 3 is a diagram showing a main part of the fluid-filled mount 34a.

[0034] As shown in FIG. 3, the fluid-filled mount 34 a includes a housing 341 , an elastic body 342 , a fluid chamber 343 , a resistance plate 344 , a shaft 347 , and a fluid pressure sensor 349 .

[0035] The housing 341 has an opening at the top. The housing 341 has a mounting hole 348 on the side. Typically, the mounting hole 348 is threaded.

[0036] Elastic body 342 is fixed to housing 341 etc. in a state where it closes the opening of housing 341. Elastic body 342 is typically made of rubber.

[0037] Shaft 347 is fixed to elastic body 342. Shaft 347 is formed in a cylindrical shape extending in the axial direction. A middle portion of shaft 347 in the axial direction is fixed to elastic body 342, and thus shaft 347 is disposed in the center of housing 341.

[0038] A fluid chamber 343 is formed by the housing 341, the elastic body 342, and the shaft 347. Viscous liquid 345 and compressed air 346 are sealed in the fluid chamber 343. The viscous liquid 345 is typically silicone oil.

[0039] The resistance plate 344 is constantly immersed in the viscous liquid 345 sealed in the fluid chamber 343. When the elastic body 342 elastically deforms, the resistance plate 344 moves together with the shaft 347 in the viscous liquid 345. This movement generates a resistance force (damping force) against the movement of the shaft 347.

[0040] The liquid pressure sensor 349 is attached to a mounting hole 348 of the housing 341. Typically, a thread is formed on an end of the liquid pressure sensor 349. The liquid pressure sensor 349 is fixed to the housing 341 by screwing the end of the liquid pressure sensor 349 into the mounting hole 348 of the housing 341.

[0041] The hydraulic pressure sensor 349 detects the hydraulic pressure of the viscous liquid 345. The hydraulic pressure sensor 349 notifies the detection result to a controller 100 (FIG. 8) that controls the operation of the hydraulic excavator 1. The hydraulic pressure sensor 349 periodically detects the hydraulic pressure and periodically transmits the detection result to the controller 100. The hydraulic pressure sensor 349 notifies the controller 100 of an electric signal that is the detection result. In this example, the hydraulic pressure sensor 349 outputs a voltage value to the controller 100.

[0042] As described above, the liquid-filled mount 34a includes the liquid pressure sensor 349 that detects the liquid pressure of the viscous liquid sealed in the liquid-filled mount 34a and outputs the detected pressure to the controller 100.

[0043] Since the liquid-filled mounts 34b, 34c, and 34d have the same configuration as the liquid-filled mount 34a, the liquid-filled mounts 34b to 34d will not be described again here. In the following description, when there is no need to distinguish between the liquid-filled mounts 34a to 34d, any one of them will be referred to as the "liquid-filled mount 34."

[0044] FIG. 4 is a diagram showing the characteristics of the hydrophilic mount 34. As shown in FIG.

[0045] 4, the liquid pressure of viscous liquid 345 and the amount of deflection (deformation) of elastic body 342 are proportional to the load applied to liquid-filled mount 34. When the load increases, the liquid pressure of viscous liquid 345 increases. Furthermore, when the load increases, the amount of deflection of elastic body 342 increases.

[0046] If the hydraulic pressure is a variable p and the deflection is a function f(p), the relationship between the hydraulic pressure and the deflection is f(p) = a × p + b. Note that a and b are coefficients. In this way, if the hydraulic pressure is known, the deflection of the elastic body 342 can be found.

[0047] The controller 100 of the hydraulic excavator 1 calculates the amount of deflection of the elastic body 342 from the hydraulic pressure of the viscous liquid 345 detected by the hydraulic pressure sensor 349 (detection result) based on the relationship between the hydraulic pressure of the viscous liquid 345 and the amount of deflection of the elastic body 342.

[0048] Next, calculation of the inclination angle of the hydraulic excavator 1 using the deflection amount of the elastic body 342 will be described.

[0049] Fig. 5A is a diagram showing a state in which the hydraulic excavator 1 is located on a horizontal plane H. Fig. 5B is a diagram showing a state in which the hydraulic excavator 1 is located on an inclined plane SL. In Fig. 5B, the inclination angle of the inclined plane SL with respect to the horizontal plane H is θ. The following describes an example in which the hydraulic excavator 1 transitions from the state in Fig. 5A to the state in Fig. 5B.

[0050] In the following, an example will be described in which three hydraulic mounts 34b, 34c, and 34d out of the four hydraulic mounts 34a to 34d are used to calculate the tilt angle θ of the hydraulic excavator 1. The tilt angle θ is an example of an index representing the “degree of tilt” of the hydraulic excavator 1.

[0051] 6 is a diagram for explaining changes in the amount of deflection (amount of displacement) of the three liquid-filled mounts 34b to 34d. In the following, the explanation will be given using an xyz coordinate system (hereinafter also referred to as a "local coordinate system") set within the hydraulic excavator 1, in addition to an XYZ coordinate system (hereinafter also referred to as a "global coordinate system").

[0052] As shown in Fig. 6, points A, B, C, and D typically represent the positions of the upper end surfaces of the elastic bodies 342 of the four hydraulic mounts 34a to 34d when the hydraulic excavator 1 is in the state shown in Fig. 5A. In this example, for the sake of convenience, point D is set as the origin (0,0,0) of the local coordinate system. In the following, the coordinates of points A, B, and C in the xyz coordinate system are (x1,0,0), (x1,y1,0), and (0,y1,0), respectively. Points B', C', and D' typically represent the positions of the upper end surfaces of the elastic bodies 342 of the three hydraulic mounts 34b to 34d when the hydraulic excavator 1 is in the state shown in Fig. 5B.

[0053] When the hydraulic excavator 1 transitions from the state of Fig. 5A to the state of Fig. 5B during a predetermined control cycle Tc (within one control cycle), the position of the upper end surface of the elastic body 342 of the liquid-filled mount 34b changes from point B to point B'. Similarly, the position of the upper end surface of the elastic body 342 of the liquid-filled mount 34c changes from point C to point C'. The position of the upper end surface of the elastic body 342 of the liquid-filled mount 34d changes from point D to point D'.

[0054] In this way, the triangle formed by the three points on the upper end surface of the elastic body 342 changes from triangle BCD to triangle B'C'D'. That is, the coordinates of each vertex of the triangle formed by the three points (hereinafter also referred to as the "target triangle") change. The coordinates of points B', C', and D' in the local coordinate system change in the z-axis direction, and become, for example, (x1, y1, zb), (0, y1, zc), and (0, 0, zd), respectively.

[0055] The controller 100 calculates the inclination angle of triangle B'C'D' with respect to triangle BCD (xy plane). In this example, triangle BCD is parallel to the XY plane of the global coordinate system. The inclination angle of triangle BCD with respect to the horizontal plane H is 0 degrees. As a result, the controller 100 calculates the inclination angle of triangle B'C'D' with respect to the horizontal plane H. Specifically, the controller 100 calculates the inclination angle θ of the hydraulic excavator 1 with respect to the horizontal plane based on the direction of the normal vector of triangle B'C'D'.

[0056] In this way, the controller 100 calculates the inclination angle of the hydraulic excavator 1 by relatively comparing the hydraulic pressures of the three hydraulic mounts 34 at the corners of the operator's cab 332. This reduces the measurement error of the inclination angle θ of the hydraulic excavator 1 relative to the horizontal plane H, and is less susceptible to disturbances when calculating the inclination angle θ. This also eliminates the need for sensor calibration, which was previously necessary.

[0057] More specifically, the cab 332 is mounted on the rotating body 33 via a hydraulic mount 34. The rotating body 33 is mounted on the running body 31 via a swing circle 32. The rotating body 33 tilts according to the tilt of the running body 31. The cab 332 tilts according to the tilt of the rotating body 33. The hydraulic pressure of each hydraulic mount 34 changes according to the tilt of the cab 332.

[0058] Therefore, as described above, the tilt angle θ of the hydraulic excavator 1 can be obtained based on the hydraulic pressure of the viscous liquid 345 in each liquid-filled mount 34. In particular, even if the attitude of the work implement 2, the load in the bucket 23, the state of the oil in the oil passage (not shown), or the state of additional options on the vehicle body change, the operator's cab 332 will not tilt unless the rotating bed 33 tilts, so the tilt angle θ can be calculated with high accuracy.

[0059] Point P1 in Fig. 6 indicates the position of the center of gravity of triangle BCD when the hydraulic excavator 1 is in the state of Fig. 5A. Point P2 indicates the position of the center of gravity of triangle B'C'D' when the hydraulic excavator 1 is in the state of Fig. 5B. When the hydraulic excavator 1 transitions from the state of Fig. 5A to the state of Fig. 5B, the position of the center of gravity of the triangle of interest (hereinafter also referred to as "center of gravity position P of the triangle of interest") moves from point P1 to point P2. The controller 100 calculates the magnitude and direction of the acceleration of the movement of the center of gravity from point P1 to point P2.

[0060] Although details will be described later, the controller 100 determines the possibility of the hydraulic excavator 1 tipping over, using the calculated inclination angle θ of the hydraulic excavator 1 with respect to the horizontal plane H and the magnitude and direction of the acceleration of the movement of the center of gravity position P of the target triangle. Note that the center of gravity position P of the target triangle is a position in the local coordinate system.

[0061] FIG. 7 is a diagram for explaining the tipping over of the hydraulic excavator 1. As shown in FIG.

[0062] As shown in Fig. 7, straight line 901 indicates an imaginary line (a straight line in the X-axis direction) of the end portion in the negative Y-axis direction of the portion of the right crawler unit 311 that contacts the inclined surface SL. Note that straight line 901 is expressed as a point because Fig. 7 is a front view of the hydraulic excavator 1. Plane 902 is an imaginary plane perpendicular to horizontal plane H. Straight line 901 is a line on plane 902.

[0063] As in Fig. 5B, the hydraulic excavator 1 is located on the inclined surface SL. The position of the center of gravity of the hydraulic excavator 1 at this time (hereinafter also referred to as "position Q of center of gravity of the work machine") is assumed to be position Q1. In this state, it is assumed that the operator, for example, rotates the rotating body 33 clockwise (the negative direction of the Y axis in Fig. 7) and raises the work machine 2, so that position Q of the center of gravity of the work machine moves from position Q1 to position Q2. Note that position Q of the center of gravity of the work machine is a position in the XYZ coordinate system.

[0064] In this case, the position Q of the center of gravity of the work machine moves to a position Q2 opposite to the position Q1 with respect to the plane 902. As a result, the hydraulic excavator 1 tips over in the direction of the arrow 903, with the line 901 as the axis of rotation.

[0065] In order to prevent such an event from occurring, the hydraulic excavator 1 determines in advance the possibility (degree of danger, signs) of the hydraulic excavator 1 tipping over, and notifies the operator of the possibility of the hydraulic excavator 1 tipping over. Hereinafter, the determination of the possibility of the hydraulic excavator 1 tipping over will be described in more detail.

[0066] FIG. 8 is a block diagram for explaining the hardware configuration of the hydraulic excavator 1 and the functional configuration of the controller 100 of the hydraulic excavator 1. As shown in FIG.

[0067] As shown in FIG. 8, the hydraulic excavator 1 includes four hydraulic mounts 34a to 34d, a controller 100, and an alarm device 400.

[0068] The liquid-filled mounts 34a to 34d each have a liquid pressure sensor 349. As described above, the liquid pressure sensor 349 detects the liquid pressure of the viscous liquid 345, and notifies the controller 100 of the detection result.

[0069] The notification device 400 includes a lamp 401, a buzzer 402, a vibration device 403, and a monitor device 404. The vibration device 403 is incorporated in an operation device such as an operation lever. The notification device 400 only needs to include at least one of the lamp 401, the buzzer 402, the vibration device 403, and the monitor device 404.

[0070] The controller 100 controls the overall operation of the hydraulic excavator 1. The controller 100 is installed in the vehicle body 3. Typically, the controller 100 is installed in the operator's cab 332.

[0071] The controller 100 includes a tilt angle calculation unit 110, an acceleration calculation unit 120, a work machine center of gravity calculation unit 130, and a determination unit 140. The tilt angle calculation unit 110 includes a deflection amount calculation unit 111, a vertex coordinate calculation unit 112, a plane identification unit 113, and a normal vector calculation unit 114. The acceleration calculation unit 120 includes a plane center of gravity calculation unit 121 and a movement amount calculation unit 122.

[0072] The inclination angle calculation unit 110 calculates the inclination angle θ of the hydraulic excavator 1 with respect to the horizontal plane H. The inclination angle calculation unit 110 calculates the inclination angle for each control period Tc. The process in the inclination angle calculation unit 110 will be described below.

[0073] The deflection calculation unit 111 calculates the amount of deflection of the elastic bodies 342 of the three liquid-filled mounts 34 based on the detection results of three pre-specified hydraulic pressure sensors 349 out of the four hydraulic pressure sensors 349. In the example of Fig. 6, the deflection calculation unit 111 calculates the amount of deflection of each of the elastic bodies 342 of the liquid-filled mounts 34b, 34c, and 34d. The deflection calculation unit 111 calculates the amount of deflection of each of the elastic bodies 342 based on the relationship between the hydraulic pressure of the viscous liquid 345 and the amount of deflection of the elastic body 342 (Fig. 4) described above.

[0074] The vertex coordinate calculation unit 112 calculates the coordinates of the three vertices of the above-mentioned target triangle (see FIG. 6) in the local coordinate system based on the deflection amounts of the three elastic bodies 342.

[0075] Based on the calculated coordinates of the three vertices, the plane identification unit 113 identifies a plane including the three coordinates in the local coordinate system. The normal vector calculation unit 114 calculates the normal vector of the plane identified by the plane identification unit 113.

[0076] The inclination angle calculation unit 110 calculates the inclination angle of the hydraulic excavator 1 with respect to the horizontal plane H based on the calculated normal vector. The inclination angle calculation unit 110 sends information on the calculated inclination angle to the work machine center of gravity calculation unit 130. The inclination angle calculation unit 110 sends information on the coordinates of the three vertices calculated by the vertex coordinate calculation unit 112 to the acceleration calculation unit 120.

[0077] The acceleration calculation unit 120 calculates the magnitude and direction of the acceleration of the movement of the center of gravity of the above-mentioned triangle of interest (see FIG. 6). The acceleration calculation unit 120 periodically (every control period Tc described above) calculates the magnitude and direction of the acceleration of the movement of the center of gravity of the triangle of interest.

[0078] The plane center of gravity calculation unit 121 periodically calculates the center of gravity position P of the target triangle based on the coordinates of the three vertices. The movement amount calculation unit 122 periodically calculates the movement amount (amount of change) of the center of gravity position P of the target triangle based on the calculation result of the plane center of gravity calculation unit 121.

[0079] The acceleration calculation unit 120 periodically calculates the magnitude and direction of the acceleration of the movement of the center of gravity P of the triangle of interest, based on the amount of movement calculated by the movement amount calculation unit 122 and the center of gravity P of the triangle of interest calculated by the planar center of gravity calculation unit 121. The acceleration calculation unit 120 sends information on the calculated magnitude and direction of the acceleration to the work machine center of gravity calculation unit 130.

[0080] The work machine center of gravity calculation unit 130 periodically calculates the center of gravity position Q (see FIG. 7) of the work machine based on the tilt angle θ and the magnitude and direction of the acceleration. The work machine center of gravity calculation unit 130 sends information on the calculated center of gravity position Q of the work machine to the determination unit 140.

[0081] The determination unit 140 determines the possibility of the hydraulic excavator 1 tipping over, based on the position Q of the center of gravity of the work machine. The determination unit 140 causes the notification device 400 to issue a notification based on the result of the determination. In detail, the determination unit 140 calculates an index value indicating the possibility of tipping over, based on the position Q of the center of gravity of the work machine. The determination unit 140 determines whether the index value has exceeded a predetermined threshold value. When the determination unit 140 determines that the index value has exceeded the threshold value, it sends a predetermined signal (command) to the notification device 400 to issue a warning to the operator.

[0082] The index value is expressed as the difference between the calculated center of gravity position Q of the work machine and a predetermined reference center of gravity position (default center of gravity position). The index value can mainly use, of the difference, the component parallel to the XY plane (horizontal plane H) in the above-mentioned XYZ coordinate system.

[0083] The reference center of gravity position is the center of gravity position when the hydraulic excavator 1 is located on the horizontal plane H. The reference center of gravity position is the center of gravity position when the revolving body 33 is not revolving. The reference center of gravity position is the center of gravity position when the work machine 2 is in a predetermined position.

[0084] When the notification device 400 receives a signal for notifying a warning from the controller 100, it notifies the operator of the warning. For example, a lamp 401 flashes. A buzzer 402 sounds. A vibration device 403 vibrates. A monitor device 404 displays a warning screen on its screen.

[0085] In this way, the notification device issues an alarm, so that the operator can be made aware of the possibility of the hydraulic excavator 1 tipping over. Therefore, the operator can prevent the hydraulic excavator 1 from tipping over by performing an operation to avoid tipping over.

[0086] The controller 100 includes a processor (not shown) and a memory in which various programs are stored. The processor executes the programs to realize a tilt angle calculation unit 110, an acceleration calculation unit 120, a work machine center of gravity calculation unit 130, and a determination unit 140. All or part of the processing in the tilt angle calculation unit 110, the acceleration calculation unit 120, the work machine center of gravity calculation unit 130, and the determination unit 140 may be realized by a dedicated arithmetic circuit such as an ASIC (Application Specific Integrated Circuit).

[0087] 9 is a flow chart for explaining the flow of processing by the controller 100. Note that the following processing is executed every control period Tc.

[0088] 9, in step S1, the controller 100 receives signals that are detection results from the hydraulic pressure sensors 349 of the multiple hydraulic mounts 34. In step S2, the controller 100 calculates the tilt angle θ of the hydraulic excavator 1 with respect to the horizontal plane H, based on the signals received from the three hydraulic pressure sensors 349. In step S3, the controller 100 calculates the magnitude and direction of the acceleration of the hydraulic excavator 1, based on the movement of the center of gravity position P of the triangle of interest.

[0089] In step S4, the controller 100 calculates the position of the center of gravity Q of the work machine based on the calculated tilt angle and the magnitude and direction of the calculated acceleration. In step S5, the controller 100 calculates an index value indicating the possibility of tipping over based on the position of the center of gravity Q of the work machine and the reference center of gravity position. In step S6, the controller 100 determines whether the calculated index value has exceeded a predetermined threshold value.

[0090] When the controller 100 determines that the index value has exceeded the threshold value (YES in step S6), in step S7 it sends a warning notification instruction to the notification device 400. As a result, the notification device 400 notifies the operator of the warning.

[0091] In step S8, the controller 100 restricts the operation of the work machine 2. For example, the controller 100 restricts the movement of the work machine 2 in a direction in which there is a possibility of tipping over, regardless of the operation by the operator. This makes it possible to reduce the possibility of the hydraulic excavator 1 tipping over.

[0092] When the controller 100 determines that the index value does not exceed the threshold value (NO in step S6), the controller 100 returns the process to step S1. When the next control cycle Tc arrives, the controller 100 repeats the processes from step S1 onwards.

[0093] A part of the configuration of the hydraulic excavator 1 described above is extracted as follows.

[0094] The hydraulic excavator 1 includes a work unit 2, a traveling body 31, a rotating body 33 rotatably supported on the traveling body 31, and a controller 100. The rotating body 33 includes a frame 331 to which the work unit 2 is attached, a cab 332, and a plurality of liquid-filled mounts 34 that are installed at different positions on the frame 331 and support the cab 332. Each liquid-filled mount 34 has a hydraulic pressure sensor 349 that detects the hydraulic pressure of a viscous liquid 345 sealed in the liquid-filled mount 34. The controller 100 calculates the inclination angle θ of the hydraulic excavator 1 with respect to the horizontal plane H based on the results of detection by each hydraulic pressure sensor 349. With this configuration, as described above, it is possible to accurately determine the inclination angle θ of the hydraulic excavator 1 with respect to the horizontal plane H.

[0095] The hydraulic excavator 1 further includes an alarm device 400. The controller 100 determines the possibility of the hydraulic excavator 1 tipping over based on the inclination angle θ. The controller 100 causes the alarm device 400 to issue an alarm based on the result of the determination. With this configuration, the operator of the hydraulic excavator 1 can know that there is a possibility that the hydraulic excavator 1 will tip over.

[0096] The controller 100 further calculates the magnitude and direction of the acceleration of the hydraulic excavator 1 based on the results of detection by each hydraulic pressure sensor 349. The controller 100 determines the possibility of the hydraulic excavator 1 tipping over based on the tilt angle θ and the magnitude and direction of the acceleration. With this configuration, the possibility of the hydraulic excavator 1 tipping over can be determined with higher accuracy than with a configuration that uses only the tilt angle θ.

[0097] The controller 100 further calculates the position of the center of gravity Q of the work machine based on the tilt angle θ and the magnitude and direction of the acceleration. The controller 100 determines the possibility of the hydraulic excavator 1 tipping over based on the position of the center of gravity Q of the work machine. Determining the possibility of tipping over based on the position of the center of gravity Q of the work machine of the hydraulic excavator 1 enables a highly accurate determination.

[0098] The controller 100 further calculates an index value indicating the possibility of the hydraulic excavator 1 tipping over, based on the position Q of the center of gravity of the work machine. When the index value exceeds a threshold value, the controller 100 causes the alarm device 400 to issue a warning.

[0099] When the index value exceeds the threshold value, the controller 100 restricts the operation of the work machine 2. With such a configuration, the possibility of the hydraulic excavator 1 tipping over can be further reduced.

[0100] The hydraulic excavator 1 includes at least three liquid-filled mounts 34. The controller 100 calculates the amount of displacement (amount of deflection) from a reference value of the liquid-filled mount 34 for each liquid-filled mount 34 based on the hydraulic pressure of the viscous liquid 345 in the three liquid-filled mounts 34. The controller 100 calculates the tilt angle θ based on the three amounts of displacement. The above-mentioned focus triangle can be formed by using the hydraulic pressure of the viscous liquid 345 in the three liquid-filled mounts 34. Therefore, the controller 100 can calculate the tilt angle θ.

[0101] <Modification> (1) In the above, the controller 100 performs processing using the detection results of the hydraulic pressure sensors 349 of the three hydraulic mounts 34b, 34c, and 34d. However, this is not limited to this. The controller 100 may use the detection results of the hydraulic pressure sensors 349 of any three of the four hydraulic mounts 34a to 34d.

[0102] (2) Focusing on a plurality of triangles, the inclination angle of each of the triangles of interest may be calculated, and the average value of these may be set as the inclination angle θ.

[0103] (3) Since the controller 100 is configured to utilize the detection results of the three hydraulic pressure sensors 349 , one of the four hydraulic mounts 34 does not necessarily need to be equipped with a hydraulic pressure sensor 349 .

[0104] (4) In the above, the determination unit 140 of the controller 100 compared the index value with one threshold value to determine whether or not to send a predetermined signal to the alarm device 400. However, this is not limited thereto, and the determination unit 140 may compare with multiple threshold values ​​(for example, Th2>Th1). In this case, when the index value exceeds the threshold value Th1, the determination unit 140 transmits a first signal to the alarm device 400. When the index value exceeds the threshold value Th2, the determination unit 140 transmits a second signal to the alarm device 400.

[0105] The notification device 400 changes the notification mode when the first signal is received and when the second signal is received. For example, when the notification device 400 receives the second signal, the level of warning is made greater than when the first signal is received. With this configuration, the operator can know that the possibility of the hydraulic excavator 1 tipping over has increased.

[0106] (5) In the above, the work machine is a hydraulic excavator. However, the present invention is not limited to this and may be any work machine having a work implement. For example, the work machine may be a bulldozer, a loader, or a grader. The work machine includes a vehicle body, a work implement, and a controller 100. The vehicle body includes a frame to which the work implement is attached, a cab, and a plurality of hydraulic mounts 34 that are installed at different positions on the frame and support the cab.

[0107] (6) In the above, it is assumed that there are multiple hydraulic pressure sensors, but if the degree of inclination is to be observed, a single hydraulic pressure sensor is also possible. A standard hydraulic pressure value for one hydraulic pressure sensor is stored, and by observing the change from the standard hydraulic pressure value, it is possible to determine whether the rubber mount of that pressure sensor is compressed or stretched, and thus the degree of inclination. The controller 100 can calculate the degree of inclination of the work machine based on the change in hydraulic pressure from the standard hydraulic pressure value previously stored in the memory of the controller 100.

[0108] The embodiments disclosed herein are merely examples and are not limited to the above. The scope of the present invention is defined by the claims, and it is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0109] 1 hydraulic excavator, 2 work machine, 3 vehicle body, 21 boom, 22 arm, 23 bucket, 31 travel body, 32 swing circle, 33 rotating body, 34a, 34b, 34c, 34d liquid-filled mount, 35 hydraulic motor, 100 controller, 110 inclination angle calculation unit, 120 acceleration calculation unit, 130 work machine center of gravity calculation unit, 140 determination unit, 211 boom cylinder, 221 arm cylinder, 231 bucket cylinder, 242 boom tip pin, 243 arm tip pin, 311 track device, 331 frame, 331a frame body, 331b beam, 332 cab, 332a front part, 332b rear part, 332c side part, 332d upper part, 332e floor board bracket, 332f Floor plate, 341 housing, 342 elastic body, 343 fluid chamber, 344 resistance plate, 345 viscous liquid, 346 compressed air, 347 shaft, 348 mounting port, 349 hydraulic pressure sensor, 400 alarm device, 901 straight line, 902 plane, H horizontal plane, P center of gravity position of target triangle, Q center of gravity position of work machine, SL inclined surface.

Claims

1. A work machine, The car body and A working machine, and a controller. The vehicle body includes a frame to which the work machine is attached, a cab, and a plurality of fluid-sealed mounts that are installed at different positions on the frame and support the cab; At least one of the plurality of fluid-filled mounts has a sensor for detecting a fluid pressure of a filled fluid; The controller calculates the degree of inclination of the work machine with respect to a horizontal plane based on the result of the detection by the sensor.

2. The work machine according to claim 1 , wherein the degree of inclination is an angle of inclination.

3. Further comprising an alarm device, The controller: determining a possibility of the work machine overturning based on the tilt angle; The work machine according to claim 2 , further comprising: a notification device that issues a notification based on a result of the determination.

4. The controller: Further calculating a magnitude and a direction of acceleration of the work machine based on the result of detection by the sensor; The work machine according to claim 3 , further comprising: a step of determining a possibility of the work machine overturning based on the inclination angle and the magnitude and direction of the acceleration.

5. The controller: further calculating a center of gravity position of the work machine based on the tilt angle and the magnitude and direction of the acceleration; The work machine according to claim 4 , wherein a possibility of the work machine tipping over is determined based on the position of the center of gravity.

6. The controller: further calculating an index value indicating the possibility of the fall based on the center of gravity position; The work machine according to claim 5 , further comprising: a warning device that issues a warning when the index value exceeds a threshold value.

7. The work machine according to claim 6 , wherein the controller limits operation of the work implement when the index value exceeds a threshold value.

8. the work machine includes at least three of the hydraulic mounts; The controller: calculating a displacement amount of each of the hydraulic mounts from a reference value based on the hydraulic pressures of the three hydraulic mounts; The work machine according to claim 3 , wherein the tilt angle is calculated based on three of the displacement amounts.

9. the work machine is a hydraulic excavator, The vehicle body includes a running body and a rotating body rotatably supported on the running body, The work machine according to claim 1 , wherein the rotating bed has the frame, the cab, and the plurality of hydraulic mounts.

10. A method for calculating an inclination degree of a work machine, comprising the steps of: The body of the work machine includes a frame to which a work implement is attached, a cab, and a plurality of hydraulic mounts that are installed at different positions on the frame and support the cab; detecting a hydraulic pressure of a liquid contained in at least one of the plurality of hydraulic mounts; a step by a controller of the work machine calculating a degree of inclination of the work machine relative to a horizontal plane based on a result of the detection.

Images