Excavator and control device

Abstract

This prevents soil from spilling when the bucket's direction is changed. [Solution] The system comprises an arm rotatably attached to a boom rotatably attached to a slewing body, a bucket rotatably attached to the arm, a tilt mechanism for tilting the bucket relative to the arm, an opening direction detection unit for detecting the direction in which the opening of the bucket faces, a tilt angle control unit for controlling the adjustment of the tilt angle of the bucket, and a vector direction calculation unit for determining the direction of the force vector applied to the bucket. The tilt angle control unit automatically controls the tilt angle using the tilt mechanism so that the opening of the bucket faces in the opposite direction to the direction of the vector determined by the vector direction calculation unit.

Description

Technical Field

[0001] The present disclosure relates to an excavator and a control device.

Background Art

[0002] In an excavator equipped with a tilt-rotator mechanism, the bucket can be oriented in any direction (see, for example, Patent Document 1). For example, it is possible to excavate while moving the bucket from the operator's front to the back, and then move the bucket from the operator's back to the front to discharge soil in the front direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when changing the direction of the bucket, it is necessary to simultaneously operate the rotations of the bucket, tilt, and rotation. Therefore, it is difficult to change the direction of the bucket without spilling the soil, especially when the bucket is filled with soil.

[0005] Therefore, it is preferable to provide an excavator that can make it difficult for soil to spill when an operation to change the direction of the bucket is performed.

Means for Solving the Problems

[0006] The excavator of the present disclosure is an arm rotatably attached to a boom rotatably attached to a revolving body, a bucket rotatably attached to the arm, a tilt mechanism for tilting the bucket with respect to the arm, An opening direction detection unit for detecting the direction in which the opening of the bucket faces, A tilt angle control unit that controls the adjustment of the tilt angle of the bucket, It includes a vector direction calculation unit that determines the direction of the force vector applied within the bucket, The tilt angle control unit automatically adjusts the tilt angle using the tilt mechanism so that the opening of the bucket faces in the opposite direction to the direction of the vector determined by the vector direction calculation unit.

[0007] Furthermore, the control device of this disclosure is An arm rotatably attached to a boom that is rotatably attached to a slewing body, A bucket rotatably attached to the aforementioned arm, A control device for an excavator having a tilt mechanism for tilting the bucket relative to the arm, An opening direction detection unit for detecting the direction in which the opening of the bucket faces, A tilt angle control unit that controls the adjustment of the tilt angle of the bucket, It includes a vector direction calculation unit that determines the direction of the force vector applied within the bucket, The tilt angle control unit automatically adjusts the tilt angle using the tilt mechanism so that the opening of the bucket faces in the opposite direction to the direction of the vector determined by the vector direction calculation unit. [Effects of the Invention]

[0008] According to this disclosure, it is possible to make it less likely for soil to spill when the direction of the bucket is changed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view of an excavator according to one embodiment of the present invention. [Figure 2] Figure 1 is a block diagram showing the configuration of the excavator's drive system. [Figure 3] This is a block diagram showing the functional configuration of the controller. [Figure 4] This is a diagram for explaining the operation of the bucket. [Figure 5] This is a flowchart for explaining the process of automatic bucket tilt control in this embodiment. [Figure 6] This is a diagram showing the state of the bucket when automatic bucket tilt control is performed in a state where no force is applied to the bucket by the excavator. [Figure 7] This is a diagram showing the state of the bucket when automatic bucket tilt control is performed in a state where force is applied to the bucket by the excavator. [Figure 8] This is a diagram for explaining an example of work that becomes possible when automatic bucket tilt control is applied. [Figure 9] This is a diagram showing an example of a system in which the excavator is remotely operated. [Embodiments for Carrying Out the Invention]

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0011] [Configuration of Excavator] FIG. 1 is a side view of an excavator according to an embodiment.

[0012] As shown in FIG. 1, an upper swing body 3 is mounted on a lower traveling body 1 of an excavator 200 via a swing mechanism 2. A boom 4 is rotatably attached to the upper swing body 3. An arm 5 is rotatably attached to the tip of the boom 4, and a bucket 6 as an end attachment is rotatably attached to the tip of the arm 5. As the end attachment, a slope bucket, a dredging bucket, or the like may be used.

[0013] The boom 4, arm 5, and bucket 6 constitute an excavation attachment as an example of an attachment, and are respectively hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9. 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 bucket6. The boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 may also be referred to as "posture sensors". The bucket cylinder 9 is an example of a rotation mechanism in the present invention.

[0014] In addition, the excavator 200 includes a tilt rotator 20 between the arm 5 and the bucket 6. The tilt rotator 20 can change the angle of the bucket 6 in the left - right direction (width direction, yaw direction: hereinafter referred to as the tilt angle) with the central part of the arm 5 as a reference point, and can also change the angle of the bucket 6 around the axis at the base end (roll direction: hereinafter referred to as the roll angle).

[0015] Therefore, the tilt rotator 20 has a tilt mechanism 23 provided on the arm 5 side and a rotator mechanism 22 provided between the tilt mechanism 23 and the bucket 6. The tilt mechanism 23 includes a base 211 fixed to the arm 5, a tilt shaft 212 connected to the base 211, a support disk 213 supported so as to be swingable with respect to the tilt shaft 212, and a tilt actuator 214 for changing the tilt angle of the support disk 213. The tilt actuator 214 is constituted by, for example, a pair of cylinder mechanisms sandwiching the tilt shaft 212.

[0016] The rotator mechanism 22 includes a rotate motor 221 fixed to the support disk 213 of the tilt mechanism 23, a rotation shaft 222 rotated by the rotate motor 221, and a connecting portion 223 connecting between the rotation shaft 222 and the bucket 6. The rotation shaft 222 projects short from the center of the support disk 213 and is continuous with the connecting portion 223. The connecting portion 223 fixes the center portion of the base end of the bucket 6, and adjusts the roll angle of the bucket 6 by rotating the bucket 6 around the central axis of the base end.

[0017] The excavator 200 rotates the entire tilt rotator 20 in the pitch direction as the arm cylinder 8 extends and retracts, thereby integrally changing the bucket angle (pitch angle) of the entire tilt rotator 20 and the bucket 6. Furthermore, the excavator 200 rotates the support plate 213 in the left-right direction relative to the base 211 as the tilt actuator 214 operates, thereby changing the tilt angle (yaw angle) of the bucket 6. For example, the tilt angle of the bucket 6 is adjusted within a range of 45° to the right to 45° to the left. Additionally, the working machine 100 rotates the connecting part 223 and the bucket 6 around an axis as the rotate motor 221 operates, thereby changing the roll angle of the bucket 6. For example, the roll angle of the bucket 6 is adjusted within a range of 360° relative to the support plate 213.

[0018] Furthermore, the tilt mechanism 23 has a bucket tilt angle sensor S5. The bucket tilt angle sensor S5 is a sensor that detects the rotation angle (tilt angle) of the bucket 6 around the tilt axis 212 and outputs the detected value. Furthermore, the rotator mechanism 22 has a rotate angle sensor S6. The rotate angle sensor S6 is a sensor that detects the angle (roll angle) around the axis of the base end of the bucket 6 and outputs the detected value.

[0019] The boom angle sensor S1 detects the rotation angle of the boom 4. In this embodiment, the boom angle sensor S1 is an acceleration sensor that detects the inclination with respect to the horizontal plane and detects the rotation angle of the boom 4 relative to the upper slewing body 3. The arm angle sensor S2 detects the rotation angle of the arm 5. In this embodiment, the arm angle sensor S2 is an acceleration sensor that detects the inclination with respect to the horizontal plane and detects the rotation angle of the arm 5 relative to the boom 4. The bucket angle sensor S3 detects the rotation angle of the bucket 6. In this embodiment, the bucket angle sensor S3 is an acceleration sensor that detects the inclination with respect to the horizontal plane and detects the rotation angle of the bucket 6 relative to the arm 5. The boom angle sensor S1, arm angle sensor S2, and bucket angle sensor S3 may be potentiometers using variable resistors, stroke sensors that detect the stroke amount of the corresponding hydraulic cylinder, rotary encoders that detect the rotation angle around the connecting pin, etc.

[0020] The upper rotating body 3 is equipped with a cabin 10 and a power source such as an engine 11. A tilt sensor S4 is also attached to the upper rotating body 3. The tilt sensor S4 is a sensor that detects the inclination of the upper rotating body 3 with respect to the horizontal plane. In this embodiment, the tilt sensor S4 is a two-axis acceleration sensor that detects the tilt angle of the upper rotating body 3 in the longitudinal and lateral directions. The tilt sensor S4 is sometimes referred to as an "attitude sensor".

[0021] The lower running body 1 is not limited to one using crawlers as shown in the figure; it may also be a wheeled shovel type with tires.

[0022] Inside the cabin 10, an input device D1, an audio output device D2, a display device D3, a storage device D4, a gate bar D5, and a controller 30 are installed.

[0023] The controller 30 is an example of a control device in the present invention and functions as a main control unit that controls the drive of the shovel. In this embodiment, the controller 30 is composed of a processing unit including a CPU and internal memory. Various functions of the controller 30 are realized by the CPU executing a program stored in the internal memory.

[0024] The input device D1 is a device for the operator of the shovel 200 to input various information. In this embodiment, the input device D1 is a membrane switch mounted on the surface of the display device D3. A touch panel or the like may also be used as the input device D1.

[0025] The audio output device D2 outputs various audio information in response to an audio output command from the controller 30. In this embodiment, an in-vehicle speaker directly connected to the controller 30 is used as the audio output device D2. Alternatively, an alarm device such as a buzzer may be used as the audio output device D2.

[0026] The display device D3 displays various image information in response to commands from the controller 30. In this embodiment, an in-vehicle liquid crystal display directly connected to the controller 30 is used as the display device D3.

[0027] The memory device D4 is a device for storing various types of information. In this embodiment, a non-volatile storage medium such as a semiconductor memory is used as the memory device D4. The memory device D4 stores various types of information output by the controller 30, etc.

[0028] The gate bar D5 is a mechanism that prevents the shovel 200 from being operated by mistake. In this embodiment, the gate bar D5 is positioned between the door of the cabin 10 and the driver's seat. When the gate bar D5 is pushed down to prevent the operator from exiting the cabin 10, the various operating devices become operable. On the other hand, when the gate bar D5 is raised to allow the operator to exit the cabin 10, the various operating devices become inoperable.

[0029] Figure 2 is a block diagram showing the configuration of the excavator's drive system as shown in Figure 1. In Figure 2, the mechanical power system is shown by double lines, the high-pressure hydraulic lines by thick solid lines, the pilot lines by dashed lines, and the electric drive and control system by thin solid lines.

[0030] Engine 11 is the power source for the shovel 200. In this embodiment, engine 11 is a diesel engine employing isochronous control to maintain a constant engine speed regardless of increases or decreases in engine load. The fuel injection amount, fuel injection timing, boost pressure, etc., in engine 11 are controlled by engine controller D7.

[0031] The engine controller D7 is a device that controls the engine 11. In this embodiment, the engine controller D7 performs various functions such as an auto idle function and an auto idle stop function.

[0032] The auto idle function is a function that reduces the engine speed from the normal speed (e.g., 2000 rpm) to the idle speed (e.g., 800 rpm) when predetermined conditions are met. In this embodiment, the engine controller D7 activates the auto idle function in response to the auto idle command from the controller 30 to reduce the engine speed to the idle speed.

[0033] The auto idle stop function is a function that stops the engine 11 when predetermined conditions are met. In this embodiment, the engine controller D7 activates the auto idle stop function in response to the auto idle stop command from the controller 30 and stops the engine 11.

[0034] Engine 11 is connected to a main pump 14 and a pilot pump 15, which function as hydraulic pumps. A control valve 17 is connected to the main pump 14 via a high-pressure hydraulic line 16.

[0035] The control valve 17 is a hydraulic control device that controls the hydraulic system of the excavator. Hydraulic actuators such as the right-side travel hydraulic motor 1A, the left-side travel hydraulic motor 1B, the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, the slewing hydraulic motor 21, and the tilt bucket cylinder 64 are connected to the control valve 17 via the high-pressure hydraulic line 16.

[0036] An operating device 26 is connected to the pilot pump 15 via a pilot line 25 and a gate lock valve D6. A control valve 17 is also connected to the pilot pump 15 via a pilot line 25A and a switching valve D8. The operating device 26 includes levers 26A and 26B, and a pedal 26C. In this embodiment, the operating device 26 is connected to the control valve 17 via a hydraulic line 27. A pressure reducing valve V1, controlled by a controller 30, is provided in the hydraulic line 27. The operating device 26 is also connected to an operating sensor 29 via a hydraulic line 28.

[0037] The gate lock valve D6 switches the connection and disconnection of the pilot line 25 connecting the pilot pump 15 and the operating device 26. In this embodiment, the gate lock valve D6 is a solenoid valve that switches the connection and disconnection of the pilot line 25 in response to a command from the controller 30. The controller 30 determines the state of the gate bar D5 based on the state signal output by the gate bar D5. When the controller 30 determines that the gate bar D5 is in a depressed state, it outputs a connection command to the gate lock valve D6. Upon receiving the connection command, the gate lock valve D6 opens and connects the pilot line 25. As a result, the operator's operation of the operating device 26 becomes effective. On the other hand, when the controller 30 determines that the gate bar D5 is in a raised state, it outputs a disconnection command to the gate lock valve D6. Upon receiving the disconnection command, the gate lock valve D6 closes and disconnects the pilot line 25. As a result, the operator's operation of the operating device 26 becomes ineffective.

[0038] The switching valve D8 switches the connection between the pilot line 25A, which connects the pilot pump 15 and the control valve 17, and shuts it off. In this embodiment, the switching valve D8 is an electromagnetic proportional valve that switches the connection between the pilot line 25A and shuts it off in response to a command from the controller 30. The controller 30 outputs a connection command to the switching valve D8 when starting the automatic bucket tilt control described later. Upon receiving the connection command, the switching valve D8 opens to connect the pilot line 25A and enable the automatic bucket tilt control.

[0039] The operation sensor 29 detects the operation content corresponding to the operation of the operating device 26. The operation sensor 29 outputs the detected operation content to the controller 30.

[0040] Next, with reference to Figure 3, the various functional elements provided in the controller 30 will be explained. Figure 3 is a functional block diagram showing the configuration of the controller 30.

[0041] In this embodiment, the controller 30 controls the operation of the entire shovel 200.

[0042] The controller 30 receives various signals and data output from the boom angle sensor S1, arm angle sensor S2, bucket angle sensor S3, machine tilt sensor S4, bucket tilt angle sensor S5, and input device D1. Based on the received signals and data, the controller 30 calculates the actual operating position of the attachment (e.g., bucket 6). If the actual operating position of the attachment differs from the target operating position, the controller 30 sends an alarm command to the voice output device D2 and display device D3 to issue an alarm.

[0043] The controller 30 includes a functional unit that performs various functions. In this embodiment, the controller 30 has an opening direction detection unit 31, a force direction detection unit 32, a vector direction calculation unit 33, a tilt angle control unit 34, and a rotation angle control unit 35 as functional units for controlling the operation of the attachment.

[0044] The opening direction detection unit 31 detects the direction in which the opening of the bucket 6 faces. In this embodiment, the bucket angle sensor S3 detects the inclination of the bucket 6 with respect to the horizontal plane. The bucket tilt angle sensor S5 detects the rotation angle (tilt angle) of the bucket 6 around the tilt axis 212. The rotate angle sensor S6 detects the angle (roll angle) around the axis of the base end of the bucket 6. Therefore, the opening direction detection unit 31 can detect the direction in which the opening of the bucket 6 faces by using the detection results of the bucket angle sensor S3, the bucket tilt angle sensor S5, and the rotate angle sensor S6.

[0045] The force direction detection unit 32 detects the magnitude and direction of the force applied to the bucket 6 as the bucket 6 moves. In this embodiment, the operation of the shovel 200 in relation to the operating device 26 is detected by the operation sensor 29. Therefore, the force direction detection unit 32 can use the detection result of the operation sensor 29 to detect the magnitude and direction of the force applied to the bucket 6 as the bucket 6 moves. For example, when the upper slewing body 3 rotates due to the operation of the operating device 26, centrifugal force is applied to the bucket 6 as the upper slewing body 3 rotates. At that time, since the operation of the operating device 26 is detected by the operation sensor 29, the force direction detection unit 32 can detect the magnitude and direction of the force due to the centrifugal force applied to the bucket 6 as the upper slewing body 3 rotates. Also, when the shovel 200 moves due to the operation of the operating device 26, an inertial force is applied to the bucket 6 as the shovel 200 starts moving due to acceleration. In this case, since the operation sensor 29 detects an operation on the operating device 26, the force direction detection unit 32 can detect the magnitude and direction of the force due to the inertial force applied to the bucket 6 as the shovel 200 moves. Alternatively, the magnitude and direction of the force applied to the bucket 6 as the bucket 6 moves may be detected using an acceleration sensor.

[0046] The vector direction calculation unit 33 determines the direction of the force vector applied to the bucket 6. Here, if the shovel 200 is not performing any actions that apply force to the bucket 6, such as turning or traveling, the only force applied to the bucket 6 is gravity. In this case, the opening direction detection unit 31 detects the direction in which the opening of the bucket 6 faces, and the vector direction calculation unit 33 can detect the relative direction of gravity with respect to the posture (opening) of the bucket 6 based on the deviation of the direction in which the opening of the bucket 6 faces relative to the vertical. Therefore, the vector direction calculation unit 33 determines the direction of gravity with respect to the posture (opening) of the bucket 6 as the direction of the force vector applied to the bucket 6. On the other hand, if the shovel 200 is performing actions that apply force to the bucket 6, such as turning or traveling, then gravity and the force generated by the movement of the bucket 6 due to the movement of the shovel 200 will be applied to the bucket 6. Therefore, the vector direction calculation unit 33 determines the direction of the force vector applied inside the bucket 6 by combining the magnitude and direction of gravity relative to the orientation (opening) of the bucket 6 and the magnitude and direction of the force generated as the bucket 6 moves, as detected by the force direction detection unit 32.

[0047] The tilt angle control unit 34 automatically controls the tilt angle of the bucket 6 using the tilt mechanism 23 so that the opening of the bucket 6 detected by the opening direction detection unit 31 faces in the opposite direction to the direction of the vector calculated by the vector direction calculation unit 33. Specifically, the tilt angle control unit 34 opens the switching valve D8 to connect the pilot line 25A and hydraulically drives the tilt bucket cylinder 64 via the control valve 17 so that the opening of the bucket 6 detected by the opening direction detection unit 31 faces in the opposite direction to the direction of the vector calculated by the vector direction calculation unit 33.

[0048] If the tilt angle control unit 34 fails to adjust the opening of the bucket 6 so that it faces the opposite direction to the vector calculated by the vector direction calculation unit 33, the rotation angle control unit 35 automatically controls and adjusts the rotation angle of the bucket 6 so that the opening of the bucket 6 faces the opposite direction to the vector calculated by the vector direction calculation unit 33. Specifically, the rotation angle control unit 35 opens the switching valve D8 to connect the pilot line 25A and hydraulically drives the bucket cylinder 9 via the control valve 17 so that the opening of the bucket 6 detected by the opening direction detection unit 31 faces the opposite direction to the vector calculated by the vector direction calculation unit 33.

[0049] [Shovel operation] The operation of the Shovel 200, configured as described above, is explained below.

[0050] First, let's explain the operation of bucket 6.

[0051] Figure 4 is a diagram illustrating the operation of bucket 6.

[0052] The excavator 200 shown in Figure 1 is equipped with a so-called tilt rotator mechanism. Therefore, the bucket 6 can be rotated not only in one direction relative to the arm 5, but also in two other directions.

[0053] Specifically, as shown in Figure 4, the bucket 6 can be rotated around the bucket axis formed by the bucket pin 61 in the direction of arrow E1 in the figure, which is the direction in which the bucket 6 is opened and closed. This rotation can be achieved by hydraulically driving the bucket cylinder 9.

[0054] Furthermore, the bucket 6 can be rotated in the direction of arrow E2 in the figure, around a rotation axis that extends in the direction connecting the arm 5 and the bucket 6.

[0055] Furthermore, the bucket 6 can be rotated in the direction of arrow E3 in the figure, around the tilt axis, in the direction that tilts the bucket 6. This rotation can be achieved by hydraulically driving the tilt bucket cylinder 64.

[0056] The rotation of these buckets 6 can be performed based on operations on the control device 26, but in the bucket tilt automatic control described later, it will also be performed according to the direction of the force vector applied to the bucket 6. As shown in Figure 1, the tilt actuator 214 and tilt shaft 212 are located on the tip side of the bucket 6 beyond the bucket cylinder 9, and the rotate motor 221 and rotating shaft 222 are located on the tip side of the bucket 6 beyond the tilt shaft 212. Thus, the tilt shaft is located at the end of the bucket shaft, and the rotate shaft is located at the end of the tilt shaft. In other words, when the bucket 6 is rotated by the bucket cylinder 9, the tilt shaft 212 and rotating shaft 222 also rotate. Also, when the bucket 6 is rotated (tilted) by the tilt actuator 214, the rotating shaft 222 also rotates.

[0057] Next, the automatic bucket tilt control in this embodiment will be described.

[0058] Figure 5 is a flowchart illustrating the process of automatic bucket tilt control in this embodiment.

[0059] In this embodiment, when the bucket tilt automatic control is functioning (on), the controller 30 executes the bucket tilt automatic control when a rotator rotation operation is performed on the bucket 6. The rotator rotation operation refers to rotating the bucket 6 in the direction of arrow E2 in Figure 4, around the rotation axis that extends in the direction connecting the arm 5 and the bucket 6.

[0060] The operation sensor 29 detects the operation performed on the operating device 26. When the operation sensor 29 detects that a rotator rotation operation has been performed on the bucket 6 (step ST11), the controller 30 executes the following automatic bucket tilt control. The operation performed on the operating device 26 is detected by the operation sensor 29, and the detected information is output to the controller 30. Therefore, the controller 30 can determine whether or not a rotator rotation operation has been performed on the bucket 6 by the operation sensor 29.

[0061] When automatic bucket tilt control is performed, first the opening direction detection unit 31 detects the direction in which the opening of the bucket 6 faces (step ST12). In this embodiment, the bucket angle sensor S3 detects the inclination of the bucket 6 with respect to the horizontal plane. In addition, the bucket tilt angle sensor S5 detects the rotation angle of the bucket 6 around the tilt axis. Therefore, the opening direction detection unit 31 can use the detection results of the bucket angle sensor S3 and the bucket tilt angle sensor S5 to detect the direction in which the opening of the bucket 6 faces.

[0062] Next, the vector direction calculation unit 33 detects the direction of gravity relative to the opening of the bucket 6 based on the deviation between the direction the opening of the bucket 6 faces and the direction of gravity (step ST13). At this time, since the opening direction detection unit 31 has detected the direction the opening of the bucket 6 faces, the vector direction calculation unit 33 can detect the direction of gravity relative to the opening of the bucket 6 based on the deviation between the direction the opening of the bucket 6 faces and the direction of gravity.

[0063] Furthermore, the controller 30 determines whether an operation to move the bucket 6 is being performed on the operating device 26 (step ST14). The operation performed on the operating device 26 is detected by the operating sensor 29, and the detected information is output to the controller 30. Therefore, the controller 30 can determine whether an operation to move the bucket 6 is being performed on the operating device 26. The operations to move the bucket 6 include operations to rotate the upper slewing body 3 and operations to move the shovel 200.

[0064] When an operation is performed on the operating device 26 to move the bucket 6 (YES in step ST14), the force direction detection unit 32 detects the magnitude and direction of the force applied to the bucket 6 as the bucket 6 moves (step ST15). The operation of the shovel 200 on the operating device 26 is detected by the operation sensor 29. Therefore, the force direction detection unit 32 can use the detection result of the operation sensor 29 to detect the magnitude and direction of the force applied to the bucket 6 as the bucket 6 moves. For example, as described above, when the upper slewing body 3 rotates due to the operation of the operating device 26, centrifugal force is applied to the bucket 6 as the upper slewing body 3 rotates. At that time, since the operation of the operating device 26 is detected by the operation sensor 29, the force direction detection unit 32 can detect the magnitude and direction of the force due to the centrifugal force applied to the bucket 6 as the upper slewing body 3 rotates. Regarding the magnitude of centrifugal force, the angular velocity of the upper rotating body 3 is detected based on the operation of the operating device 26, and the magnitude of the force due to centrifugal force applied to the bucket 6 can be detected according to that angular velocity. Furthermore, when the shovel 200 moves due to the operation of the operating device 26, an inertial force is applied to the bucket 6 due to acceleration at the start of the shovel 200's movement. At that time, since the operation sensor 29 detects the operation of the operating device 26, the force direction detection unit 32 can detect the magnitude and direction of the force due to the inertial force applied to the bucket 6 as the shovel 200 moves. Regarding the magnitude of the force due to inertial force, the acceleration of the shovel 200 is detected based on the operation of the operating device 26, and the magnitude of the force due to the inertial force applied to the bucket 6 can be detected according to that acceleration.

[0065] Next, the vector direction calculation unit 33 determines the direction of the force vector acting inside the bucket 6 (step ST16). Here, if no operation is performed on the operating device 26 to move the bucket 6 (NO in step ST14), the only force acting inside the bucket 6 is gravity. In that case, the vector direction calculation unit 33 determines the direction of gravity relative to the opening of the bucket 6 as the direction of the force vector acting inside the bucket 6.

[0066] On the other hand, if it is determined in step ST14 that an operation to move the bucket 6 is being performed on the operating device 26, and if the magnitude and direction of the force acting inside the bucket 6 as the bucket 6 moves is detected in step ST15, then gravity and the force generated as a result of the bucket 6 moving due to the operation of the shovel 200 will be acting inside the bucket 6.

[0067] Therefore, the vector direction calculation unit 33 determines the direction of the force that is a combination of gravity and the force generated by the movement of the bucket 6 due to the operation of the shovel 200. In this case, unlike the case where no operation is performed on the operating device 26 to move the bucket 6 and the only force acting on the bucket 6 is gravity, in order to combine the forces, not only the direction of the combined forces but also the magnitude of the forces is required. This is because the acceleration due to gravity is constant, while the centrifugal force and inertial force fluctuate depending on the angular velocity of the bucket 6 and the acceleration of the shovel 200.

[0068] Therefore, the vector direction calculation unit 33 combines a vector based on the direction of gravity and gravitational acceleration relative to the opening of the bucket 6 with a vector based on the magnitude and direction of the force generated as the bucket 6 moves, as detected by the force direction detection unit 32, to determine the direction of the force vector applied to the bucket 6. Specifically, it combines a vector having a length corresponding to the gravitational acceleration and pointing in the direction of gravity relative to the opening of the bucket 6 with a vector having a length corresponding to the magnitude of the force (centrifugal force, inertial force) generated as the bucket 6 moves and pointing in the direction of the force generated as the bucket 6 moves, to determine the direction of the force vector applied to the bucket 6. Here, as mentioned above, the gravitational acceleration is constant. Therefore, even if the direction of the force generated as the bucket 6 moves is the same, the larger its magnitude (centrifugal force, inertial force), the more the combined vector will be tilted from the vertical.

[0069] Next, the tilt angle control unit 34 automatically controls the tilt angle of the bucket 6 using the tilt mechanism 23 so that the direction in which the opening of the bucket 6, as detected by the opening direction detection unit 31, faces is opposite to the direction of the vector determined by the vector direction calculation unit 33 (step ST17). Here, the direction in which the opening of the bucket 6 faces is detected by the opening direction detection unit 31, and the tilt angle of the bucket 6 is detected by the bucket tilt angle sensor S5. Therefore, the tilt angle control unit 34 adjusts the tilt angle of the bucket 6 detected by the bucket tilt angle sensor S5 so that the opening of the bucket 6, as detected by the opening direction detection unit 31, faces in the opposite direction to the direction of the vector determined by the vector direction calculation unit 33. At that time, the tilt angle control unit 34 tilts the bucket 6 by opening the switching valve D8, connecting the pilot line 25A, and hydraulically driving the tilt bucket cylinder 64 via the control valve 17.

[0070] Figure 6 shows the state of bucket 6 when automatic bucket tilt control is performed while the shovel 200 is not performing any action that applies force to the bucket 6, and Figure 7 shows the state of bucket 6 when automatic bucket tilt control is performed while the shovel 200 is performing an action that applies force to the bucket 6.

[0071] When the shovel 200 is not performing any actions that would apply force to the bucket 6 due to its movement, such as rotating or traveling, the only force acting on the bucket 6 is gravity. Therefore, when the automatic bucket tilt control described above is performed, the tilt angle control unit 34 adjusts the tilt angle of the bucket 6 so that the direction B1 in which the opening 6a of the bucket 6 faces is opposite to the direction A1 in which gravity faces, as shown in Figure 6.

[0072] On the other hand, when the shovel 200 is rotating or traveling, or performing other actions that apply force to the bucket 6 due to the movement of the bucket 6, the bucket 6 will be subjected to both gravity and the force generated by the movement of the bucket 6 due to the operation of the shovel 200. Therefore, when the automatic control described above is performed, as shown in Figure 7, first, the vector direction calculation unit 33 combines the vector A2, which is the magnitude and direction of gravity, and the vector C1, which is the magnitude and direction of the force generated by the movement of the bucket 6 detected by the force direction detection unit 32, to determine the vector direction E4 of the force vector applied to the bucket 6. Then, the tilt angle control unit 34 adjusts the tilt angle of the bucket 6 so that the direction B2, which is the direction the opening 6a of the bucket 6 faces, is opposite to the vector direction E4 of the vector determined by the vector direction calculation unit 33.

[0073] In this case, the adjustment range for the tilt angle of bucket 6 may be set to, for example, ±45°. In that case, simply adjusting the tilt angle of bucket 6 may not cause the opening of bucket 6 detected by the opening direction detection unit 31 to face in the opposite direction to the vector calculated by the vector direction calculation unit 33.

[0074] Therefore, in addition to control to tilt the bucket 6, control to rotate the bucket 6 may also be used.

[0075] If, even after adjusting the tilt angle of the bucket 6 in step ST17, the opening of the bucket 6 detected by the opening direction detection unit 31 still does not face the opposite direction to the vector calculated by the vector direction calculation unit 33 (step ST18), the rotation angle control unit 35 automatically controls and adjusts the rotation angle of the bucket 6 so that the opening of the bucket 6 detected by the opening direction detection unit 31 faces the opposite direction to the vector calculated by the vector direction calculation unit 33 (step ST19). Here, the direction that the opening of the bucket 6 faces is detected by the opening direction detection unit 31, and the inclination of the bucket 6 with respect to the horizontal plane is detected by the bucket angle sensor S3 as the rotation angle of the bucket 6. Therefore, the rotation angle control unit 35 adjusts the rotation angle of the bucket 6 detected by the bucket angle sensor S3 so that the opening of the bucket 6 detected by the opening direction detection unit 31 faces the opposite direction to the vector calculated by the vector direction calculation unit 33. At that time, the rotation angle control unit 35 opens the switching valve D8 to connect the pilot line 25A and hydraulically drives the bucket cylinder 9 via the control valve 17, thereby rotating the bucket 6.

[0076] As described above, in this embodiment, in order to control the shovel 200 having an arm 5 rotatably attached to a boom 4 rotatably attached to an upper slewing body 3, a bucket 6 rotatably attached to the arm 5, and a tilt mechanism 23 that tilts the bucket 6 relative to the arm 5, the system includes an opening direction detection unit 31 that detects the direction in which the opening of the bucket 6 faces, a tilt angle control unit 34 that controls the adjustment of the tilt angle of the bucket 6, and a vector direction calculation unit 33 that determines the direction of the force vector applied inside the bucket 6. The tilt angle control unit 34 automatically controls the tilt angle using the tilt mechanism 23 so that the opening of the bucket 6 faces in the opposite direction to the direction of the vector determined by the vector direction calculation unit 33. This makes it less likely for soil to spill when the direction of the bucket is changed.

[0077] Furthermore, the system includes a bucket cylinder 9 that rotates the bucket 6 relative to the arm 5, and a rotation angle control unit 35 that controls the adjustment of the rotation angle of the bucket 6. If the adjustment of the tilt angle control unit 34 does not allow the opening of the bucket 6 to face in the opposite direction to the vector calculated by the vector direction calculation unit 33, the rotation angle control unit 35 automatically adjusts the rotation angle of the bucket 6 so that the opening of the bucket 6 faces in the opposite direction to the vector determined by the vector direction calculation unit 33. This makes it possible to prevent soil from spilling when tilting the bucket, even if the adjustment of the tilt angle control unit 34 alone does not allow the opening of the bucket 6 to face in the opposite direction to the vector determined by the vector direction calculation unit 33 due to limitations on the tilt angle, etc.

[0078] Furthermore, the vector direction calculation unit 33 determines the direction of the force vector applied to the bucket 6 based on the gravitational force acting on the bucket 6 and the force acting on the bucket 6 as the bucket 6 moves. With this configuration, even if a force is applied to the bucket 6 as the bucket 6 moves, the tilt angle is adjusted according to that force, making it less likely for soil to spill when the tilt operation is performed.

[0079] Furthermore, the vector direction calculation unit 33 calculates the relative direction of gravity with respect to the attitude of the bucket 6 based on the deviation of the direction in which the opening of the bucket 6 faces relative to the vertical direction. With this configuration, if the direction of the opening of the bucket 6 is detected, the relative direction of gravity with respect to the attitude of the bucket 6 can be detected.

[0080] Furthermore, the bucket 6 is configured to be rotatable, and the tilt angle control unit 34 adjusts the tilt angle of the bucket 6 when an operation is performed to rotate the bucket 6. With this configuration, the tilt angle can be automatically adjusted only when an operation is performed that causes the contents of the bucket 6, such as soil, to spill out of the bucket 6.

[0081] The following describes the tasks that become possible when the aforementioned bucket tilt automatic control is applied.

[0082] Figure 8 illustrates an example of work that becomes possible when the aforementioned bucket tilt automatic control is applied.

[0083] When the aforementioned bucket tilt automatic control is applied, first, as shown in Figure 8(a), the bucket 6 is rotated around the rotation axis, allowing excavation to be performed by scooping from below. This makes it possible to excavate without changing the direction of the shovel 200 or moving the shovel 200 according to the condition of the construction surface.

[0084] Subsequently, with the excavated soil contained in the bucket 6, the upper rotating body 3 is rotated as shown in Figure 8(b). At this time, the opening 6a of the bucket 6 is facing upward. Since the bucket 6 is now rotating around its rotation axis, if the bucket 6 is to be rotated around its axis to discharge the soil, the soil will be discharged towards the back of the bucket 6 from the perspective of the operator of the shovel 200.

[0085] In that case, the operator of the shovel 200 would have difficulty seeing the excavated soil because it would be obscured by the bucket 6. Therefore, as shown in Figure 8(c), after rotating the upper rotating body 3, the bucket 6 is rotated around the rotation axis to return to its original position.

[0086] Furthermore, as shown in Figure 8(d), by rotating the bucket 6 around its axis to discharge soil, the soil will be discharged in front of the bucket 6 from the perspective of the operator of the shovel 200. This prevents the operator of the shovel 200 from seeing the discharged soil obscured by the bucket 6.

[0087] In this type of work, when rotating the bucket 6 around the rotation axis, if the bucket 6 is tilted at an angle from the direction the opening 6a of the bucket 6 faces, there is a possibility that the soil and sand contained in the bucket 6 may spill out. Therefore, as described above, by adjusting the tilt angle of the bucket 6 so that the opening 6a of the bucket 6 faces in the opposite direction to the direction of the vector applied to the inside of the bucket 6, it is possible to reduce the likelihood of the soil and sand contained in the bucket 6 spilling out.

[0088] Furthermore, the automatic bucket tilt control described above is effective in preventing the spillage of soil and sand contained in the bucket 6. For this reason, the automatic bucket tilt control may be configured so that the tilt angle control unit 34 does not adjust the tilt angle of the bucket 6 when the rotator is rotated on the bucket 6 while the bucket 6 is empty. With this configuration, the automatic bucket tilt control, which is performed to prevent the spillage of soil and sand contained in the bucket 6, can be operated only when necessary. In this case, a sensor may be used to detect the amount and weight of soil and sand in the bucket 6.

[0089] Furthermore, if the amount of soil in bucket 6 is small, it is expected that the soil will not spill easily even without precisely adjusting the tilt angle of bucket 6. For this reason, the precision of the range of the tilt angle of bucket 6 to be adjusted may be changed according to the amount of soil in bucket 6. For example, if the amount of soil in bucket 6 is small, the precision of the range of the tilt angle of bucket 6 to be adjusted may be set to ±20%, and if the amount of soil in bucket 6 is above a certain amount, the precision of the range of the tilt angle of bucket 6 to be adjusted may be set to ±5%.

[0090] In this embodiment, automatic bucket tilt control is performed when a rotator rotation operation is performed on the bucket 6. However, automatic bucket tilt control may also be performed when an operation other than rotator rotation is performed, such as a rotation operation of the upper slewing body 3.

[0091] Furthermore, the shovel 200 may be configured such that some or all of its driven elements, such as the lower traveling body 1, upper slewing body 3, boom 4, arm 5, and bucket 6, are electrically driven by electric actuators. In other words, the shovel 200 may be a hybrid shovel or an electric shovel.

[0092] (Other embodiments) Instead of being configured to be operated by an operator sitting in the cabin 10, or in addition to being configured to be remotely operated from outside the shovel 200, the shovel 200 may also be configured to be remotely operated. When the shovel 200 is remotely operated, the interior of the cabin 10 may be unoccupied.

[0093] Figure 9 shows an example of a system in which the 200 excavator is remotely controlled.

[0094] As shown in Figure 9, the shovel 200 may be operated from a remote control room RC.

[0095] The remote control room RC is equipped with a remote controller 40, a sound output device RD2, an indoor imaging device RC1, a display device RD3, and a communication device T. The remote control room RC also has a driver's seat DS where the operator OP sits to remotely control the shovel 200.

[0096] The remote controller 40 is an example of a control device in the present invention and is an arithmetic unit that performs various calculations. In this embodiment, the remote controller 40, like the controller 30, is composed of a microcomputer including a CPU and memory. The various functions of the remote controller 40 are realized by the CPU executing a program stored in memory.

[0097] The sound output device RD2 is configured to output sound. In this embodiment, the sound output device RD2 is a speaker and is configured to reproduce the sound collected by a sound collection device (not shown) attached to the shovel 200.

[0098] The indoor imaging device RC1 is configured to image the inside of the remote control room RC. In this embodiment, the indoor imaging device RC1 is a camera installed inside the remote control room RC and is configured to image the operator OP seated in the driver's seat DS.

[0099] The communication device T is configured to control wireless communication with a communication device (not shown) attached to the shovel 200.

[0100] A remote control device 126, including an engine speed adjustment dial 75, is provided near the driver's seat DS. The engine speed adjustment dial 75 is a dial for adjusting the rotational speed of the engine 11, and is configured to allow switching of the engine speed in four stages, for example, SP mode, H mode, A mode, and idling mode. The remote control device 126 is equipped with an operation sensor 129 that detects the operation of the remote control device 126. This allows detection of the operation of the remote control device 126. In addition to a pressure sensor that detects pressure on the remote control device 126, the sensor for detecting the operation of the remote control device 126 may also be a tilt sensor that detects the tilt angle of the operation lever, or an angle sensor that detects the swing angle around the pivot axis of the operation lever. Furthermore, the sensor for detecting the operation of the remote control device 126 may consist of other sensors such as a pressure sensor, a current sensor, a voltage sensor, or a distance sensor. The operation sensor 129 outputs the detected pressure value to the remote controller 40. The remote controller 40 generates an operation signal based on the received pressure value and transmits the generated operation signal to the shovel 200.

[0101] The display device RD3 is configured to display information about the surrounding conditions of the shovel 200. In this embodiment, the display device RD3 is a multi-display consisting of nine monitors arranged in three vertical rows and three horizontal columns, and is configured to display the conditions of the space in front of, to the left of, and to the right of the shovel 200. Each monitor is an LCD monitor or an OLED monitor, etc. However, the display device RD3 may consist of one or more curved monitors or may consist of a projector.

[0102] The display device RD3 may be a display device that can be worn by the operator OP. For example, the display device RD3 may be a head-mounted display and may be configured to send and receive information to and from the remote controller 40 via wireless communication. The head-mounted display may be wired to the remote controller 40. The head-mounted display may be a transparent head-mounted display or an opaque head-mounted display. The head-mounted display may be a monocular head-mounted display or a binocular head-mounted display.

[0103] The display device RD3 is configured to display images that allow the operator OP in the remote control room RC to visually inspect the area around the shovel 200. In other words, the display device RD3 displays images that allow the operator to check the situation around the shovel 200 as if they were inside the cabin 10 of the shovel 200, even though they are in the remote control room RC.

[0104] In a remote control room RC configured in this way, the remote controller 40 may also have the functions of the functional unit of the controller 30 of the shovel 200, which consists of an opening direction detection unit 31, a force direction detection unit 32, a vector direction calculation unit 33, a tilt angle control unit 34, and a rotation angle control unit 35, and perform the bucket tilt automatic control described above. [Explanation of Symbols]

[0105] 1. Lower running body 2. Swivel mechanism 3. Upper rotating body 4 Boom 5 Arms 6 buckets 6a opening 7 Boom Cylinder 8 Arm Cylinder 9 Bucket Cylinder 10 cabins 11 Engine 14 Main pump 15 Pilot pump 16 High-pressure hydraulic line 17 Control valve 20 Tilt Rotator 22 Rotator mechanism 23 Tilt mechanism 26 Operating device 29,129 Operation Sensors 30 controllers 31 Aperture direction detection unit 32 Force direction detection unit 33 Vector direction calculation unit 34 Tilt Angle Control Unit 35 Rotation Angle Control Unit 40 Remote Controllers 126 Remote control device 200 Shovel 212 Tilt axis 214 Tilt Actuator 221 Rotating Motor 222 Rotating shaft S1 Boom Angle Sensor S2 Arm Angle Sensor S3 Bucket Angle Sensor S4 Aircraft tilt sensor S5 Bucket Tilt Angle Sensor S6 Rotator Angle Sensor D1 Input Device D2, RD2 Audio Output Device D3, RD3 Display Device D4 storage device D5 Gate Bar D6 Gate Lock Valve D7 Engine Controller D8 Switching valve RC1 Indoor Imaging Device T Communication device

Claims

1. An arm rotatably attached to a boom that is rotatably attached to a slewing body, A bucket rotatably attached to the aforementioned arm, A tilt mechanism that tilts the bucket relative to the arm, An opening direction detection unit for detecting the direction in which the opening of the bucket faces, A tilt angle control unit that controls the adjustment of the tilt angle of the bucket, It includes a vector direction calculation unit that determines the direction of the force vector applied within the bucket, The tilt angle control unit automatically adjusts the tilt angle using the tilt mechanism so that the opening of the bucket faces in the opposite direction to the direction of the vector determined by the vector direction calculation unit, in this excavator.

2. The bucket is configured to be rotatable, The excavator according to claim 1, wherein the tilt angle control unit adjusts the tilt angle when an operation is performed to rotate the bucket.

3. A rotating mechanism that rotates the bucket relative to the arm, The bucket has a rotation angle control unit that controls the adjustment of the rotation angle of the bucket, The excavator according to claim 1 or 2, wherein the rotation angle control unit automatically controls the rotation angle so that the opening of the bucket faces in the opposite direction to the direction of the vector calculated by the vector direction calculation unit if the adjustment of the tilt angle control unit does not result in the opening of the bucket facing in the opposite direction to the direction of the vector calculated by the vector direction calculation unit.

4. The excavator according to claim 1, wherein the vector direction calculation unit determines the direction of the force vector applied to the bucket based on the gravity applied to the bucket and the force applied to the bucket as the bucket moves.

5. The excavator according to claim 3, wherein the vector direction calculation unit determines the relative direction of gravity with respect to the attitude of the bucket based on the deviation of the direction in which the opening of the bucket faces with respect to the vertical direction.

6. The excavator according to claim 1, wherein the tilt angle control unit does not adjust the tilt angle when there is no contents in the bucket.

7. An arm rotatably attached to a boom that is rotatably attached to a slewing body, A bucket rotatably attached to the aforementioned arm, A control device for an excavator having a tilt mechanism for tilting the bucket relative to the arm, An opening direction detection unit for detecting the direction in which the opening of the bucket faces, A tilt angle control unit that controls the adjustment of the tilt angle of the bucket, It includes a vector direction calculation unit that determines the direction of the force vector applied within the bucket, The tilt angle control unit is a control device that automatically controls the tilt angle using the tilt mechanism so that the opening of the bucket faces in the opposite direction to the direction of the vector determined by the vector direction calculation unit.

Images