Work machinery

Abstract

To appropriately control a revolving parking brake.SOLUTION: This work machine comprises: a lower carriage; an upper turning body; a revolving parking brake 30; a revolving parking brake solenoid 32a; a revolving releasing switch 38; a switching element 17; a second contact 38T; and a main controller 10. The switching element 17 switches the state of a first circuit between a conductive stage and a non-conductive state in response to a command from a cutoff control unit 11b. At the second contact 38T, the state of a second circuit is switched between a conductive stage and a non-conductive state in accordance with an operation of the revolving releasing switch 38.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to work machines. [Background technology]

[0002] Hydraulic excavators and other work machines are equipped with a function that activates a swing parking brake to stop the upper rotating body in the event of an abnormality in the electric motor or the drive control system for the electric motor that drives the swing mechanism of the upper rotating body. If the upper rotating body is stopped and held at an angle relative to the undercarriage at this time, it may become difficult to move the vehicle. Therefore, a swing release switch is provided to release the swing parking brake. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2011 / 142447 Summary of the Invention [Problem to be solved by the invention]

[0004] If an abnormality occurs in the circuit including the swing parking brake, the swing parking brake may not be properly controlled. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a work machine comprising: a lower running body; an upper rotating body arranged to be rotatable relative to the lower running body; a swing braking device that stops the swing of the upper rotating body relative to the lower running body; an actuator that controls the activation and release of the swing braking device; a first switching member that releases the swing braking device; a second switching member that switches between a conductive state and a non-conductive state of a first circuit provided between a downstream terminal of the actuator and ground; a fourth switching member that switches between a conductive state and a non-conductive state of a second circuit provided between the downstream terminal of the actuator and ground; and a controller, wherein the second switching member switches between the conductive state and the non-conductive state of the first circuit based on a command from the controller, and the fourth switching member switches between the conductive state and the non-conductive state of the second circuit based on operation of the first switching member. [Effects of the Invention]

[0006] According to an aspect of the present invention, a work machine capable of appropriately controlling a swing parking brake can be provided. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic configuration diagram of a work machine according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram of a circuit including a swing parking brake of the work machine according to the first embodiment. [Figure 3] FIG. 3 is a schematic block diagram of the work machine according to the first embodiment. [Figure 4] FIG. 4 is a block diagram showing a computer system according to the first embodiment. [Figure 5] FIG. 5 is a flowchart showing the processing carried out by the main controller of the work machine according to the first embodiment. [Figure 6] FIG. 6 is a flowchart showing the processing carried out by the main controller of the work machine according to the first embodiment. [Figure 7] FIG. 7 is a schematic diagram of a circuit including a swing parking brake of a conventional work machine. [Figure 8] FIG. 8 is a schematic block diagram of a conventional work machine. [Figure 9] FIG. 9 is a schematic block diagram of a work machine according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings, but the present disclosure is not limited thereto. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0009] (First embodiment) [Work machinery] FIG. 1 is a schematic configuration diagram of a work machine 1 according to a first embodiment. FIG. 2 is a schematic diagram of a circuit including a swing parking brake 30 of the work machine 1 according to the first embodiment. FIG. 3 is a schematic block diagram of the work machine 1 according to the first embodiment. In this embodiment, the work machine 1 is a hydraulic excavator. The work machine 1 comprises a lower traveling body (not shown), an upper rotating body 2, a work implement (not shown), and a hydraulic cylinder (not shown) that drives the work implement.

[0010] The upper rotating body 2 supports a working machine. The working machine includes a boom, arm, and bucket (not shown). A driver's seat (not shown) is provided on the upper rotating body 2. The upper rotating body 2 is attached to the lower traveling body so that it can rotate.

[0011] The work machine 1 includes an engine 5, a generator motor 6, a capacitor 7, a swing motor (electric motor) 3, an inverter 9, a main controller 10, and a hydraulic pump 8.

[0012] A generator motor 6 for generating electricity and driving motor is connected to the output shaft of the engine 5. The generator motor 6 generates electricity through power generation and supplies the electricity to the swing motor 3 and the capacitor 7. The swing motor 3 generates a driving force for swinging the upper swing body 2 relative to the lower traveling body. The capacitor 7 stores the electricity to be supplied to the generator motor 6 or the swing motor 3. An inverter 9 controls the electricity supplied to the generator motor 6, swing motor 3, and capacitor 7. A main controller 10 controls the swing motor 3 and the inverter 9.

[0013] The hydraulic pump 8 is driven by the engine 5 and the generator motor 6. The hydraulic pump 8 is connected to the drive shaft of the generator motor 6. The pressure oil discharged from the hydraulic pump 8 is supplied to work machine hydraulic cylinders 41, 42, 43 and traveling hydraulic motors 44, 45 via a valve 40. For example, the work machine hydraulic cylinders 41, 42, 43 are hydraulic cylinders that operate a boom, an arm, and a bucket, respectively, not shown. The traveling hydraulic motors 44, 45 are hydraulic motors that rotate the right and left crawlers of the undercarriage, not shown, respectively. The traveling hydraulic motors 44, 45 are rotated in response to operation of an operator control device, not shown.

[0014] When the work implement control levers 46a, 46b, 46c are operated, pressure oil is supplied to the work implement hydraulic cylinders 41, 42, 43, respectively, and the boom, arm, and bucket (not shown) are respectively operated.

[0015] The work implement control levers 46a, 46b, 46c are provided with pilot pressure sensors 50a, 50b, 50c, respectively, that detect pilot pressures that change in accordance with the amount of operation. The pilot pressure sensors 50a, 50b, 50c are pressure sensors that detect pressures that change in accordance with the amount of operation (angle) of the work implement control levers 46a, 46b, 46c, respectively, and output an electrical signal of a value that corresponds to the detected pressure. Note that sensors other than pressure sensors, such as potentiometers, that can detect the amount of operation, may also be used to output similar electrical signals. When it is not necessary to distinguish between the pilot pressure sensors 50a, 50b, 50c, they will be described as pilot pressure sensors 50. A signal indicating the pilot pressure detected by the pilot pressure sensor 50 (hereinafter referred to as the "work implement operation signal") is input to the main controller 10.

[0016] The swing operation lever 4 is an operation lever that rotates and drives the swing motor 3. When the swing operation lever 4 is operated, the swing motor 3 is rotated and the upper swing body 2 is operated to swing relative to the lower traveling body. The rotation speed of the swing motor 3 is reduced by the swing machinery 9a.

[0017] The swing operation lever 4 is provided with a pilot pressure sensor 51 that detects a pilot pressure that changes in accordance with the amount of operation. More specifically, the swing operation lever 4 is provided with a left pilot pressure sensor 51a and a right pilot pressure sensor 51c. The left pilot pressure sensor 51a detects the left pilot pressure that indicates the amount of left turning. The right pilot pressure sensor 51c detects the right pilot pressure that indicates the amount of right turning. When there is no need to distinguish between the left pilot pressure sensor 51a and the right pilot pressure sensor 51c, they will be described as pilot pressure sensors 51. The pilot pressure sensor 51 is a pressure sensor that detects pressure that changes in accordance with the amount of operation (angle) of the swing operation lever 4, and outputs an electrical signal of a value that corresponds to the detected pressure. Note that a sensor other than a pressure sensor, such as a potentiometer, that can detect the amount of operation may also be used to output a similar electrical signal. A signal indicating the pilot pressure detected by the pilot pressure sensor 51 (hereinafter referred to as the "swing operation signal") is input to the main controller 10.

[0018] The pilot pressure sensors 50 and 51 can be installed anywhere as long as they can detect the amount of operation of the corresponding control lever. For example, they may be attached to the corresponding control lever, or may be installed in the piping downstream of the corresponding control valve.

[0019] A swing operation signal detected by a pilot pressure sensor 51 attached to the swing operation lever 4 is input to the swing control section 11 of the main controller 10 via a signal line 81 .

[0020] In this embodiment, for convenience of explanation, the boom, arm, bucket, and upper rotating body 2 (not shown) are individually associated with the work machine control levers 46a, 46b, 46c and the swing control lever 4, respectively. However, it is also possible to use a single control lever to operate any two combinations of the boom, arm, bucket, and upper rotating body 21 by operating them up, down, left, or right, and a single control lever to operate the other two combinations by operating them up, down, left, or right. For example, control levers can be provided on both the left and right sides of the driver's seat, with the arm and upper rotating body 2 associated with the left control lever and the bucket and boom associated with the right control lever. In this case, the upper rotating body 2 is operated to the right swing side when the left control lever is tilted upward and to the left swing side when the left control lever is tilted downward. The arm (not shown) is operated to the dump side when the left control lever is tilted left, and to the excavation side when the left control lever is tilted right.

[0021] A main controller 10, which will be described later, generates a drive signal according to the amount of operation of the swing operation lever 4. The main controller 10 outputs the generated drive signal to the swing motor 3 to drive the upper swing body 2 to rotate.

[0022] [Slewing parking brake] The swing parking brake (swing braking device) 30 brakes the upper swing structure 2. The swing parking brake 30 stops the rotation of the upper swing structure 2 relative to the undercarriage. More specifically, when the swing operation lever 4 is placed in the neutral position, the servo system of the swing motor 3 holds the position of the swing motor 3, and the swing parking brake 30 is activated, holding the upper swing structure 2 stopped. If an abnormality such as a failure occurs in the swing motor 3 or the CPU that controls the swing motor 3, the swing parking brake 30 is activated to hold the upper swing structure 2 stopped.

[0023] When the rod 31a of the brake hydraulic cylinder 31 of the swing parking brake 30 abuts against the drive shaft 3a of the swing motor 3, the drive shaft 3a of the swing motor 3 is locked and the upper swing body 2 is held stationary. This state is called the brake activated state. Note that a disc brake system may be employed in which a disc plate is provided on the drive shaft 3a of the swing motor 3 and the drive shaft 3a of the swing motor 3 is locked by clamping this disc plate with brake pads.

[0024] When the rod 31a of the brake hydraulic cylinder 31 is separated from the drive shaft 3a of the swing motor 3, the drive shaft 3a of the swing motor 3 is released from the locked state, and the upper swing body 2 becomes free to swing. This state is called a brake released state.

[0025] More specifically, pressurized oil is supplied to the oil chamber 31b of the brake hydraulic cylinder 31 via a pressure reducing valve 8b, an oil passage 8c, and a brake control valve 32, which are provided in the discharge oil passage 8a of the hydraulic pump 8, so that the rod 31a of the brake hydraulic cylinder 31 separates from the drive shaft 3a of the swing motor 3, and the swing parking brake 30 is released.

[0026] The swing parking brake solenoid 32a controls the operation and release of the swing parking brake 30. When an ON electrical signal (hereinafter referred to as a "brake release command signal") is applied to the attached swing parking brake solenoid (actuator) 32a of the brake control valve 32, the swing parking brake solenoid 32a is driven and the valve position is set to the release state, releasing the swing parking brake 30. The swing parking brake solenoid 32a is an electromagnetic solenoid. When energized, the swing parking brake solenoid 32a releases the swing parking brake 30, and when de-energized, the swing parking brake solenoid 32a activates the swing parking brake 30.

[0027] An ON electrical signal applied to the swing parking brake solenoid 32 a, that is, a brake release command signal, is output from an output terminal 35 of the main controller 10 .

[0028] The output terminal 35 of the main controller 10 is electrically connected to the swing parking brake solenoid 32a of the brake control valve 32 via an electric signal line 34. When a brake release command signal is output to the output terminal 35 of the main controller 10, an ON electric signal is applied to the swing parking brake solenoid 32a of the brake control valve 32 via the electric signal line 34, causing the swing parking brake 30 to be released.

[0029] A switch (third switching member) 36 is provided in the electrical signal line 34 for electrically connecting or disconnecting the electrical connection of the electrical signal line 34. The switch 36 is a swing lock switch. The swing lock switch 36 is manually operated to activate or release the swing parking brake 30. When the swing lock switch 36 is placed in the ON position 36a, the swing parking brake solenoid 32a of the brake control valve 32 is driven via the electrical signal line 34, and the swing parking brake 30 is released. The swing lock switch 36 is manually placed in the OFF position 36b when it is desired to stop and hold the upper swing body 2. When the swing lock switch 36 is placed in the OFF position 36b, the electrical signal line 34 is electrically disconnected in that switch position, and the swing parking brake 30 is activated. The swing lock switch 36 switches the circuit connecting the swing parking brake solenoid 32a and the battery 33, which is the power source, between a conductive state and a non-conductive state.

[0030] 1, the battery 33 is provided to supply an ON electric signal to the swing parking brake solenoid 32a of the brake control valve 32. The positive terminal 33a of the battery 33 is electrically connected to the electric signal line 34 via the electric signal line 39.

[0031] If an abnormality such as a failure occurs in the swing motor 3 or the CPU that controls the swing motor 3 and the swing parking brake 30 is activated, the upper swing structure 2 may be stopped and held in a state where it is difficult for the work machine 1 to move. For example, the upper swing structure 2 may be stopped and held in a state where the boom, arm, etc. are at an angle to the traveling direction of the lower traveling structure. For this reason, a switch (first switching member) 38 is provided for releasing the swing parking brake 30. The switch 38 releases the swing parking brake 30 when an abnormality occurs in the circuit including the swing parking brake 30. The switch 38 is a swing release switch.

[0032] The swing release switch 38 has a first contact 38S that is provided between the upstream terminal of the swing parking brake solenoid 32a and the power supply. In this embodiment, the swing release switch 38 includes the first contact 38S and a second contact (fourth switching member) 38T. The swing release switch 38 is provided with the second contact 38T in parallel with the first contact 38S.

[0033] The first contact 38S switches between a conductive state and a non-conductive state of the circuit connecting the upstream terminal of the swing parking brake solenoid 32a and the power supply. More specifically, the first contact 38S is disposed midway along the electrical signal line 39 and is configured to electrically connect or disconnect the electrical signal line 39. The first contact 38S is disposed in the circuit on the power supply side of the swing lock switch 36 and switches between a conductive state and a non-conductive state of the circuit provided between the upstream terminal of the swing parking brake solenoid 32a and the power supply.

[0034] The second contact 38T switches between a conductive state and a non-conductive state of the second circuit C2, which connects the downstream terminal of the swing parking brake solenoid 32a and the ground 38TG. More specifically, the second contact 38T is disposed on the second circuit C2, which is provided between the downstream terminal of the swing parking brake solenoid 32a and the ground 38TG, and switches between a conductive state and a non-conductive state of the second circuit C2, which is provided between the downstream terminal of the swing parking brake solenoid 32a and the ground 38TG. The second contact 38T switches between a conductive state and a non-conductive state of the second circuit C2 based on the operation of the swing release switch 38. In this embodiment, the second contact 38T is switched in conjunction with the swing release switch 38.

[0035] The first contact 38S and the second contact 38T are switched in conjunction with each other. The first contact 38S is switched on and off in synchronization with the second contact 38T. More specifically, when the first contact 38S is switched to a conductive state, the swing release switch 38 switches the second contact 38T to a conductive state. When the first contact 38S is in a conductive state, the swing release switch 38 sets the second contact 38T to a conductive state. When the first contact 38S is in a non-conductive state, the swing release switch 38 sets the second contact 38T to a non-conductive state.

[0036] Normally, the first contact 38S and the second contact 38T of the swing release switch 38 are positioned at OFF positions 38Sa and 38Ta, respectively, which are in a non-conductive state. When it is desired to freely swing the upper swing body 2, the swing release switch 38 is manually operated so that the first contact 38S and the second contact 38T of the swing release switch 38 are in ON positions 38Sb and 38Tb, respectively, which are in a conductive state. This brings the circuit between the upstream terminal of the swing parking brake solenoid 32a and the power supply into a conductive state, and also brings the second circuit C2 between the downstream terminal of the swing parking brake solenoid 32a and ground 38TG into a conductive state. Voltage is applied to the swing parking brake solenoid 32a, and the swing parking brake 30 is released.

[0037] [Main Controller] The main controller 10 implements a function as a drive control unit 11a and a function as a shutoff control unit 11b. In other words, the drive control unit 11a and the shutoff control unit 11b are provided within the main controller 10. An electric signal line 34 is electrically connected to the main controller 10 via an output terminal 35. The main controller 10 outputs a drive control signal to the swing motor 3 to control the swing motor 3, and also generates a brake release command signal to release the swing parking brake 30 and outputs it to the swing parking brake solenoid 32a of the brake control valve 32.

[0038] The main controller 10 includes a swing control unit 11, which will be described later, an abnormality monitoring unit 12 that monitors abnormalities in the swing control unit 11, a switching element 14, a switching element 16, and a switching element (second switching member) 17.

[0039] The swing control unit 11 switches the switching element 16 and the switching element 17 on and off. The swing control unit 11 implements the function of a drive control unit 11a that outputs commands to the swing parking brake solenoid 32a to activate and release the swing parking brake 30. The swing control unit 11 generates a brake release command signal based on the swing operation signal and the work implement operation signal. When the swing control unit 11 determines that the content of the swing operation signal indicates that "the swing operation lever 4 has been operated from the neutral position" or that the content of the work implement operation signal indicates that "at least one of the work implement operation levers 46a, 46b, 46c has been operated from the neutral position," the swing control unit 11 generates a brake release command signal and outputs it to the switching element 16. If the swing control unit 11 determines that the content of the swing operation signal indicates that "the swing operation lever 4 is in the neutral position" and that the content of the work equipment operation signal indicates that "all of the work equipment operation levers 46a, 46b, 46c are in the neutral position," the swing control unit 11 does not generate a brake release command signal.

[0040] The swing control unit 11 may generate a brake release command signal based only on the swing operation signal. If the swing control unit 11 determines that the content of the swing operation signal indicates that "the swing operation lever 4 has been operated from the neutral position," the swing control unit 11 generates a brake release command signal and outputs it to the switching element 16. If the swing control unit 11 determines that the content of the swing operation signal indicates that "the swing operation lever 4 is located in the neutral position," the swing control unit 11 does not generate a brake release command signal.

[0041] The swing control unit 11 may generate a brake release command signal based only on the work implement operation signal. When the swing control unit 11 determines that the content of the work implement operation signal indicates that "at least one of the work implement control levers 46a, 46b, 46c has been operated from the neutral position," the swing control unit 11 generates a brake release command signal and outputs it to the switching element 16. This is because, since the servo of the swing motor 3 is working, there is no problem even if the brakes are released based only on the operation of the work implement operation levers 46a, 46b, 46c. When the swing control unit 11 determines that the content of the work implement operation signal indicates that "all of the work implement operation levers 46a, 46b, 46c are in the neutral position," the swing control unit 11 does not generate a brake release command signal.

[0042] The swing control unit 11 implements the function of a shutoff control unit 11b that outputs a command to shut off the first circuit C1 provided between the downstream terminal of the swing parking brake solenoid 32a and ground 17G. For example, when the swing control unit 11 detects a power fault on the upstream side of the swing lock switch 36, it generates a swing parking brake actuation command signal. If the swing control unit 11 determines that it has detected that the feedback voltage is equal to or greater than the threshold, it generates a swing parking brake actuation command signal and outputs it to the switching element 17. If the swing control unit 11 does not determine that it has detected that the feedback voltage is equal to or greater than the threshold, it does not generate a swing parking brake actuation command signal.

[0043] The abnormality monitoring unit 12 switches the switching element 14 between on and off. More specifically, if the abnormality monitoring unit 12 detects an abnormality in the swing control unit 11, it outputs an OFF electrical signal as a switching signal to the switching element 14 in order to activate the swing parking brake 30. If the abnormality monitoring unit 12 does not detect an abnormality in the swing control unit 11, it outputs an ON electrical signal as a switching signal to the switching element 14.

[0044] The switching element 14 is disposed on a circuit that receives power from the power supply side of the main controller 10. The switching element 14 switches the circuit between a conductive state and a non-conductive state based on a command from the abnormality monitoring unit 12. The switching element 14 is, for example, a field effect transistor (FET) or a transistor. When the switching element 14 is in a conductive state, a voltage is applied to the swing parking brake solenoid 32a. When the switching element 14 is in a non-conductive state, no voltage is applied to the swing parking brake solenoid 32a.

[0045] The switching element 16 switches the circuit between a conductive state and a non-conductive state based on a command from the swing control unit 11. The switching element 16 is, for example, an FET or a transistor. When the switching element 16 is in a non-conductive state, the power supply to the upstream terminal of the swing lock switch 36 is cut off. As a result, no voltage is applied to the swing parking brake solenoid 32a of the brake control valve 32, and the swing parking brake 30 is activated. When the switching element 16 is in a conductive state, power is supplied to the upstream side of the swing lock switch 36. As a result, voltage is applied to the swing parking brake solenoid 32a of the brake control valve 32, and the swing parking brake 30 is released.

[0046] More specifically, when an ON electrical signal, i.e., a brake release command signal, is input to the switching element 16 from the swing control unit 11 as a switching signal, the switching element 16 outputs an ON electrical signal, i.e., a brake release command signal. The switching element 16 is electrically connected to an electrical signal line 34 via an output terminal 35. As a result, when a brake release command signal is generated by the main controller 10, the brake release command signal is output to the swing parking brake solenoid 32a of the swing parking brake 30, causing the swing parking brake 30 to enter a released state.

[0047] The switching element 17 is provided to activate the swing parking brake 30 when a power fault occurs at the upstream terminal of the swing parking brake solenoid 32a. The switching element 17 is disposed on a first circuit C1 provided between the downstream terminal of the swing parking brake solenoid 32a and ground 17G in the main controller 10. The switching element 17 switches the first circuit C1, which is provided between the downstream terminal of the swing parking brake solenoid 32a and ground 17G, between a conductive state and a non-conductive state. The switching element 17 switches between a conductive state and a non-conductive state based on a command from the swing control unit 11, which functions as the cutoff control unit 11b. The switching element 17 cuts off the first circuit C1 based on a command from the swing control unit 11. The switching element 17 is, for example, an FET or a transistor. The switching element 17 is normally in a conductive state, and the first circuit C1 downstream of the swing parking brake solenoid 32a (on the ground 17G side) is not cut off. For example, if a power fault occurs upstream (on the power supply side) of the swing lock switch 36, the switching element 17 becomes non-conductive, and the first circuit C1 downstream of the swing parking brake solenoid 32a is cut off. This drives the swing parking brake solenoid 32a of the brake control valve 32, and the swing parking brake 30 enters an activated state. The switching element 17 becomes non-conductive when an OFF electrical signal, that is, a swing parking brake activation command signal, is input from the swing control unit 11 as a switching signal. When the main controller 10 generates a swing parking brake activation command signal, the swing parking brake activation command signal is output to the switching element 17, and the switching element 17 becomes non-conductive.

[0048] [Computer System] FIG. 4 is a block diagram showing a computer system 1000 according to the first embodiment. The controller 60 described above includes the computer system 1000. The computer system 1000 includes a processor 1001 such as a CPU (Central Processing Unit), a main memory 1002 including a nonvolatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory), a storage 1003, and an interface 1004 including an input / output circuit. The functions of the main controller 10 described above are stored as a program in the storage 1003. The processor 1001 reads the program from the storage 1003, loads it into the main memory 1002, and executes the above-described processing in accordance with the program. The program may be distributed to the computer system 1000 via a network.

[0049] [Slewing parking brake control processing] Next, the processing procedure of the embodiment will be described with reference to the flowcharts shown in Figures 5 and 6. Figure 5 is a flowchart showing the processing content carried out by the main controller 10 of the work machine 1 according to the first embodiment. Figure 6 is a flowchart showing the processing content carried out by the main controller 10 of the work machine 1 according to the first embodiment.

[0050] Generation of the brake release command signal will be described using Figure 5. The swing control unit 11 determines whether the swing operation lever 4 and the work implement operation levers 46a, 46b, 46c are all in neutral (step S101). More specifically, the swing control unit 11 determines whether the content of the swing operation signal indicates that "the swing operation lever 4 is in the neutral position" and whether the content of the work implement operation signal indicates that "all of the work implement operation levers 46a, 46b, 46c are in the neutral position."

[0051] If the swing control unit 11 determines that the swing operation lever 4 and the work implement operation levers 46a, 46b, 46c are all in the neutral position (Yes in step S101), the process proceeds to step S102. More specifically, if the swing control unit 11 determines that the content of the swing operation signal indicates that "the swing operation lever 4 is in the neutral position" and the content of the work implement operation signal indicates that "all of the work implement operation levers 46a, 46b, 46c are in the neutral position," the process proceeds to step S102.

[0052] If the swing control unit 11 determines that at least one of the swing operation lever 4 and the work implement operation levers 46, 46b, 46c is not in the neutral position (No in step S101), the process proceeds to step S104. More specifically, if the swing control unit 11 determines that the content of the swing operation signal indicates that "the swing operation lever 4 has been operated from the neutral position" or the content of the work implement operation signal indicates that "at least one of the work implement operation levers 46a, 46b, 46c has been operated from the neutral position", the process proceeds to step S104.

[0053] The swing control unit 11 determines whether or not a predetermined time (for example, 5 seconds) has elapsed since the swing operation lever 4 and the work machine operation levers 46a, 46b, 46c were all placed in the neutral position (step S102).

[0054] If the rotation control unit 11 determines that a predetermined time (e.g., 5 seconds) has elapsed since the rotation operation lever 4 and all of the work equipment operation levers 46a, 46b, and 46c were positioned in the neutral position (Yes in step S102), the process proceeds to step S103.

[0055] If the rotation control unit 11 determines that a predetermined time (e.g., 5 seconds) has not elapsed since the rotation operation lever 4 and all of the work equipment operation levers 46a, 46b, and 46c were positioned in the neutral position (No in step S102), proceed to step S104.

[0056] The swing control unit 11 determines that the swing parking brake 30 should be activated and does not generate a brake release command signal (step S103). As a result, the swing parking brake 30 remains activated, and the upper swing body 2 remains unable to swing.

[0057] The swing control unit 11 determines that the swing parking brake 30 should be released, and generates a brake release command signal (step S104). As a result, the swing parking brake 30 is released, and the upper swing body 2 becomes free to swing.

[0058] The generation of the swing parking brake activation command signal will be described with reference to Figure 6. The swing control unit 11 determines whether or not a fault such as a power fault has been detected upstream of the swing lock switch 36 (step S111). More specifically, the swing control unit 11 determines whether or not it has detected that the feedback voltage is equal to or greater than a threshold value.

[0059] If it is determined that a failure has been detected on the upstream side of the swing lock switch 36 (Yes in step S111), the process proceeds to step S112. More specifically, if the swing control unit 11 detects that the feedback voltage is equal to or greater than the threshold value, the process proceeds to step S112.

[0060] If the swing control unit 11 determines that no failure has been detected upstream of the swing lock switch 36 (No in step S111), it ends the process. More specifically, if the swing control unit 11 does not detect that the "feedback voltage is equal to or greater than the threshold value," it ends the process.

[0061] If the swing control unit 11 determines in step S111 that a failure has been detected on the upstream side of the swing lock switch 36, it determines that the swing parking brake 30 should be activated and generates a swing parking brake activation command signal (step S112). As a result, the swing parking brake 30 is activated and the upper swing body 2 cannot swing.

[0062] As described above, in this embodiment, the switching element 17 is disposed on the first circuit C1 provided between the downstream terminal of the swing parking brake solenoid 32a and the ground 17G. In this embodiment, the switching element 17 switches between a conductive state and a non-conductive state based on a command from the swing control unit 11 serving as the interruption control unit 11b. According to this embodiment, if an abnormality occurs in the circuit including the swing parking brake 30, the swing parking brake 30 can be activated.

[0063] In this embodiment, the swing release switch 38 is provided with a first contact 38S and a second contact 38T. The first contact 38S switches between a conductive state and a non-conductive state of a circuit connecting an upstream terminal of the swing parking brake solenoid 32a and a power supply. The second contact 38T switches between a conductive state and a non-conductive state of a second circuit C2 connecting a downstream terminal of the swing parking brake solenoid 32a and a ground 38TG. The first contact 38S and the second contact 38T are switched in conjunction with each other. In other words, when the first contact 38S is switched to a conductive state, the swing release switch 38 switches the second contact 38T to a conductive state. When the first contact 38S is switched to a non-conductive state, the swing release switch 38 switches the second contact 38T to a non-conductive state. According to this embodiment, when an abnormality occurs in the circuit including the swing parking brake 30, the swing parking brake 30 can be released.

[0064] In this embodiment, a turning operation signal detected by the pilot pressure sensor 51 is input to the main controller 10.

[0065] A conventional swing parking brake control device for a work machine 1 will be described using Figures 7 and 8. Figure 7 is a schematic diagram of a circuit including a swing parking brake 30 of a conventional work machine 1. Figure 8 is a schematic block diagram of the conventional work machine 1. The downstream terminal of the swing parking brake solenoid 32a is connected to ground without passing through a switching element or the like. As a result, if an abnormality occurs upstream of the swing parking brake solenoid 32a, the circuit downstream of the swing parking brake solenoid 32a will not be shut off, the swing parking brake 30 will remain in a released state, and the upper swing body 2 may remain in a freely swingable state.

[0066] Second Embodiment A work machine 1 according to this embodiment will be described using Figure 9. Figure 9 is a schematic block diagram of a work machine 1 according to a second embodiment. The basic configuration of the work machine 1 is similar to that of the work machine 1 of the first embodiment. In the following description, components that are similar to those of the work machine 1 are given the same or corresponding reference numerals, and detailed description thereof will be omitted. The work machine 1 of this embodiment differs from the first embodiment in that the fourth switching member is a relay 38X.

[0067] The relay 38X is provided between the downstream terminal of the swing parking brake solenoid 32a and the swing release switch 38. The relay 38X is connected to the swing release switch 38 via a circuit 381X.

[0068] The relay 38X switches the second circuit C2, which is provided between the downstream terminal of the swing parking brake solenoid 32a and ground 38XG, between a conductive state and a non-conductive state based on the operation of the swing release switch 38. In this embodiment, the relay 38X switches the second circuit C2 between a conductive state and a non-conductive state based on the operation of the swing release switch 38. In this embodiment, the relay 38X switches the second circuit C2 to a conductive state when the first contact 38S of the swing release switch 38 is switched to a conductive state. More specifically, when the first contact 38S of the swing release switch 38 is switched to a conductive state, a voltage is applied to the coil 38XC of the relay 38X. When a voltage is applied to the coil 38XC, the contact 38XS of the relay 38X is switched to a conductive state, and the downstream terminal of the swing parking brake solenoid 32a and ground 38XG are connected to each other via the second circuit C2.

[0069] Normally, the first contact 38S of the swing release switch 38 and the contact 38XS of the relay 38X are positioned at the OFF position 38Sa and OFF position 38XSa, respectively, which are non-conductive. To allow the upper swing unit 2 to swing freely, the swing release switch 38 is manually operated so that the first contact 38S of the swing release switch 38 is positioned at the ON position 38Sb, which is conductive. This establishes a conductive state in the circuit between the upstream terminal of the swing parking brake solenoid 32a and the power supply, applying voltage to the swing parking brake solenoid 32a. Furthermore, voltage is applied to the coil 38XC, which sets the contact 38XS of the relay 38X to the ON position 38Xb, thereby establishing a conductive state in the second circuit C2, which is located between the downstream terminal of the swing parking brake solenoid 32a and ground 38XG. This activates the swing parking brake solenoid 32a, releasing the swing parking brake 30.

[0070] As described above, in this embodiment, the relay 38X is used as the fourth switching member to switch the second circuit C2 between a conductive state and a non-conductive state. According to this embodiment, similar to the first embodiment, when an abnormality occurs in the circuit including the swing parking brake 30, the swing parking brake 30 can be released.

[0071] In the embodiment, the description is based on the assumption that the work machine 1 is a hybrid, but the invention is not limited to this and can be applied to electric work machines and hydraulic work machines. In the embodiment, the description is based on the assumption that the swing motor 3 is an electric motor, but the invention is not limited to this and the swing motor 3 may be a hydraulic motor that is driven by hydraulic pressure.

[0072] In the first embodiment shown in FIG. 5, a judgment process in step S102 is provided, and the condition for putting the swing parking brake 30 into an activated state is that a predetermined time (e.g., 5 seconds) or more has elapsed since the swing operation lever 4 and the work equipment operation levers 46a, 46b, 46c are all positioned in the neutral position. However, the judgment process in step S102 may be omitted and the swing parking brake 30 may be put into an activated state.

[0073] In the second embodiment, the fourth switching member is the relay 38X, but the present invention is not limited to this. The fourth switching member may be, for example, an active element or a discrete component. [Explanation of symbols]

[0074] 1...work machine, 2...upper swing body, 3...swing motor (electric motor), 3a...drive shaft, 4...swing operation lever, 5...engine, 6...generator motor, 7...capacitor, 8...hydraulic pump, 9...inverter, 10...main controller, 11...swing control section, 11a...drive control section, 11b...shutoff control section, 12...abnormality monitoring section, 14...switching element, 16...switching element, 17...switching element (second switching member), 30...swing parking brake (swing braking device), 31...brake hydraulic cylinder, 31a...rod, 31b...oil chamber, 32...brake control valve, 32a...swing parking brake solenoid (actuator), 33...battery, 33a...positive terminal, 34...electrical signal Line, 35...output terminal, 36...swing lock switch (third switching member), 36a...on position, 36b...off position, 38...swing release switch (first switching member), 38S...first contact, 38T...second contact (fourth switching member), 38Sb, 38Tb...on position, 38Sa, 38Ta...off position, 39...electrical signal line, 40...valve, 41, 42, 43...hydraulic cylinder for work equipment, 44, 45...hydraulic motor for travel, 46a, 46b, 46c...work equipment operation lever, 50...pilot pressure sensor, 50a, 50b, 50c...pilot pressure sensor, 51...pilot pressure sensor, 51a...left pilot pressure sensor, 51c...right pilot pressure sensor, C1...first circuit, C2...second circuit.

Claims

1. a lower running body; an upper rotating body arranged to be rotatable relative to the lower traveling body; a rotation braking device that stops the rotation of the upper rotating body relative to the lower traveling body; an actuator for controlling the activation and release of the turning braking device; a controller that generates a command signal to drive the actuator; a first switching member that is disposed between an upstream terminal of the actuator and a power source and that is manually operated to drive the actuator to release the turning brake device; a second switching member disposed in the controller and configured to switch a first circuit provided between a downstream terminal of the actuator and ground between a conductive state and a non-conductive state; a third switching member that is provided on an electric signal line that transmits the command signal from the controller to an upstream terminal of the actuator, and that is manually operated to activate the turning braking device; a fourth switching member that switches a second circuit between a conductive state and a non-conductive state and is provided between a downstream terminal of the actuator and a ground that is disposed downstream of the first switching member; Equipped with the controller generates a command signal for driving the actuator to release the swing braking device based on at least one of a swing operation signal and a work implement operation signal; the actuator controls activation and release of the turning brake device based on the command signal from the controller for driving the actuator to release the turning brake device; the controller generates a command signal to activate the turning brake device when detecting a failure on the upstream side of the third switching member; the second switching member switches the first circuit between a conductive state and a non-conductive state based on the command signal from the controller for operating the turning brake device, the fourth switching member switches the second circuit between a conductive state and a non-conductive state based on a manual operation of the first switching member; Work machinery.

2. the fourth switching member switches the second circuit to a conductive state when the first switching member is switched to a conductive state; 2. The work machine according to claim 1.

3. The fourth switching member is switched in conjunction with the first switching member.

2. The work machine according to claim 1.

4. the first switching member has a first contact point provided between an upstream terminal of the actuator and a power source, The fourth switching member is a second contact point.

4. The work machine according to claim 3.

5. the second contact switches the second circuit to a conductive state when the first contact is switched to a conductive state; 5. The work machine according to claim 4.

6. the actuator is an electromagnetic solenoid, which releases the turning brake device when excited and activates the turning brake device when de-energized; A work machine according to any one of claims 1 to 5.

7. The controller includes a drive control unit that controls the actuator and a cutoff control unit that controls the second switching member. A work machine according to any one of claims 1 to 6.

8. Further provided is an electric motor that generates a driving force for rotating the upper rotating body relative to the lower traveling body. A work machine according to any one of claims 1 to 7.

Images