Working machinery

Abstract

To make the swivel parking brake work more reliably. [Solution] The work machine 1 comprises a lower traveling body, an upper rotating body, a rotating parking brake 30, a brake control valve 32, a rotating release switch 38, and a controller 10. The controller 10 comprises a first input terminal T12 and a second input terminal T13 connected to the rotating release switch 38, an output terminal T11 electrically connected to the upstream terminal of the brake control valve 32 via the rotating release switch 38, and a connection circuit that switches between a conductive state in which a voltage capable of operating the brake control valve 32 is applied to the rotating release switch 38 from the output terminal T11, and a non-conductive state in which no voltage is applied, and controls the connection circuit based on inputs from the first input terminal and the second input terminal.

Description

Technical Field

[0001] This disclosure relates to a working machine.

Background Art

[0002] In a working machine such as a hydraulic excavator, a function is provided to engage a swing parking brake and stop and hold the upper swing body with respect to the lower traveling body. At this time, if the upper swing body is stopped and held at an angle with respect to the lower traveling body, it may be difficult to move the vehicle. Therefore, a switch for releasing the swing parking brake is provided.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a working machine, it is desired to make the swing parking brake operate more reliably.

Means for Solving the Problems

[0005] According to an aspect of the present invention, a work machine is provided comprising a lower traveling body, an upper rotating body rotatably arranged relative to the lower traveling body, a rotating braking device for stopping the rotation of the upper rotating body relative to the lower traveling body, an actuator for controlling the engagement and disengagement of the rotating braking device, a first switch for receiving an operation to release the rotating braking device, and a controller. The controller comprises a first input terminal and a second input terminal connected to the first switch, an output terminal electrically connected to the upstream terminal of the actuator via the first switch, and a connection circuit that switches between a conductive state in which a voltage capable of operating the actuator is applied to the first switch from the output terminal and a non-conductive state in which no voltage is applied, and controls the connection circuit based on inputs from the first input terminal and the second input terminal. [Effects of the Invention]

[0006] According to aspects of the present invention, the swivel parking brake can be operated more reliably. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram showing the configuration of a work machine according to an embodiment. [Figure 2] Figure 2 is a schematic diagram showing the electrical circuit of the swivel parking brake system of a work machine according to the embodiment. [Figure 3] Figure 3 is a block diagram showing a computer system according to an embodiment. [Figure 4] Figure 4 is a flowchart showing the processing performed by the controller of the work machine according to the embodiment. [Modes for carrying out the invention]

[0008] The embodiments described below will be explained with reference to the drawings, but the 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] (Embodiment) [Working machinery] Figure 1 is a schematic diagram showing the configuration of a work machine according to an embodiment. Figure 2 is a schematic diagram showing the electrical circuit of the slewing parking brake system of the work machine 1 according to an embodiment. In this embodiment, the work machine 1 is a hydraulic excavator. The work machine 1 comprises a lower traveling body 2A, an upper slewing body 2B, a work implement (not shown), and hydraulic cylinders 41, 42, and 43 for driving the work implement.

[0010] The upper slewing body 2B is rotatably supported relative to the lower traveling body 2A. The upper slewing body 2B supports the implement, which includes a boom, arm, and attachments (not shown).

[0011] The work machine 1 includes a hydraulic pump 8, an operating device 4, a swivel parking brake 30, a swivel release switch 38, a swivel lock switch 36, and a controller 10.

[0012] The hydraulic pump 8 is driven by a power source 5, which is, for example, an engine. The discharged pressurized oil from the hydraulic pump 8 is supplied via valve 40 to hydraulic cylinders 41, 42, 43, a hydraulic travel motor (not shown), and a hydraulic slewing motor 3. For example, the hydraulic cylinders 41, 42, and 43 are configured to operate a boom, arm, and attachment (not shown), respectively. The hydraulic travel motors are hydraulic motors that rotate the right and left tracks of the lower travel body 2A (not shown), respectively. The hydraulic slewing motor 3 generates the driving force to rotate the upper slewing body 2B relative to the lower travel body 2A. The rotational speed of the hydraulic slewing motor 3 is reduced by a swing machine (not shown). Valve 40 and power source 5 are controlled by controller 10.

[0013] The control device 4 is an operating device for driving the boom, arm, and attachments (not shown), and for rotating the upper slewing body 2B. The control device is, for example, an operating lever located on both the left and right sides of the driver's seat. The control device 4 outputs an operating signal according to the amount of operation. The amount of operation is detected by a rotation angle sensor, for example, a potentiometer. The operating signal is output as an electrical signal corresponding to the amount of operation. The operating signal output from the control device 4 is input to the controller 10. Based on the operating signal from the control device 4, the controller 10 controls an electromagnetic proportional valve (not shown) that changes the amount of operation of a valve 40 that adjusts the flow rate and direction of pressurized oil from the hydraulic pump 8 so that the hydraulic cylinders 41, 42, 43 and the hydraulic slewing motor 3 are driven, respectively. If the control device is a hydraulic pilot type, the amount of operation may be detected by a pilot pressure sensor, and the detected electrical operating signal may be input to the controller 10. Furthermore, the control levers may be configured such that any two combinations of the slewing, boom, arm, and attachments are controlled by a single control lever for up, down, left, and right movements, while the other two combinations are controlled by another control lever for up, down, left, and right movements.

[0014] [Swivel parking brake] The slewing parking brake (slewing braking device) 30 is configured to stop and hold the rotation of the upper slewing body 2B relative to the lower traveling body 2A. In this embodiment, the slewing parking brake 30 includes a brake cylinder 31 and a brake control valve 32 (actuator). The slewing parking brake is engaged or released by operating the operating device that operates the upper slewing body. When the slewing operating lever is operated from neutral to the drive side, the brake is released. When the slewing operating lever is in the neutral position, the brake is engaged. Note that the engagement and release of the brake may be determined by the operating state of at least one operating lever corresponding to the boom, arm, or attachment, or it may be determined together with the slewing, including the operating state of at least one operating lever corresponding to the boom, arm, or attachment.

[0015] The brake cylinder 31 has a rod 31a and an oil chamber 31b. The rod 31a moves when hydraulic fluid is supplied to the oil chamber 31b. In this embodiment, the brake cylinder 31 is configured to contract when hydraulic fluid is supplied to the oil chamber 31b. The oil chamber 31b of the brake cylinder 31 is connected to the discharge oil passage 8a of the hydraulic pump 8 via a brake control valve 32 in the hydraulic circuit.

[0016] The brake control valve 32 controls the engagement and release of the slewing parking brake 30. The brake control valve 32 controls the extension and retraction of the brake cylinder 31. The brake control valve 32 supplies hydraulic fluid from the hydraulic pump 8 to operate the brake cylinder 31. The brake control valve 32 is configured to supply hydraulic fluid to the oil chamber 31b of the brake cylinder 31. In the hydraulic circuit, the brake control valve 32 is located between the discharge oil passage 8a of the hydraulic pump 8 and the oil chamber 31b of the brake cylinder 31.

[0017] When hydraulic fluid is supplied from the brake control valve 32 to the oil chamber 31b, the brake cylinder 31 retracts, and the rod 31a moves away from the drive shaft 3a of the hydraulic swing motor 3. As a result, the upper swing body 2B can freely swing relative to the lower traveling body 2A. This state is called the brake release state.

[0018] If hydraulic fluid is not supplied to the oil chamber 31b from the brake control valve 32, the brake cylinder 31 extends due to the biasing means, and the rod 31a comes into contact with the drive shaft 3a of the hydraulic swing motor 3. As a result, the upper swing body 2B is held in a stopped position relative to the lower traveling body 2A. This state is called the brake engaged state. Alternatively, a disc brake system may be adopted in which a disc plate is provided on the drive shaft 3a of the hydraulic swing motor 3, and the drive shaft 3a of the hydraulic swing motor 3 is locked by sandwiching this disc plate with brake pads.

[0019] The brake control valve 32 includes a brake solenoid 32a. The brake solenoid 32a is an electromagnetic solenoid. The brake solenoid 32a is configured to release the swing parking brake 30 when a voltage is applied and to engage the swing parking brake 30 when no voltage is applied. When a voltage is applied to the brake solenoid 32a, the brake solenoid 32a is driven, and the valve position of the brake control valve 32 becomes a communication position where hydraulic oil from the hydraulic pump 8 can be supplied. Thereby, hydraulic oil is supplied to the oil chamber 31b of the brake cylinder 31, and the swing parking brake 30 is released. When no voltage is applied to the brake solenoid 32a, the brake solenoid 32a is not driven, and the valve position of the brake control valve 32 becomes a closed position. Thereby, hydraulic oil is not supplied to the oil chamber 31b of the brake cylinder 31, and the swing parking brake 30 is engaged.

[0020] The upstream terminal of the brake solenoid 32a is electrically connected to the common terminal 38b3 of the second switching portion 38b of a swing release switch 38 described later. The downstream terminal of the brake solenoid 32a is electrically connected to the common terminal 38d3 of the fourth switching portion 38d of the swing release switch 38.

[0021] The battery 33 is an example of an external power source mounted on the work machine. The battery outputs a voltage of, for example, 24V. The battery 33 is electrically connected to the controller 10. The voltage applied to the brake solenoid 32a is output from the battery 33. The battery 33 is electrically connected to the output terminal T11 of the controller 10 via the first switching element 12 of the controller 10. The battery 33 is electrically connected to the common terminal 38a3 of the first switching portion 38a of the swing release switch 38.

[0022] [Swing Release Switch] The slewing release switch (first switch) 38 is operated by the operator to temporarily release the slewing parking brake 30. For example, if the controller 10 malfunctions and voltage cannot be applied to the brake solenoid 32a, the upper slewing body 2B may be stopped and held in a state where it is difficult to move the work machine 1. In such cases, the slewing release switch 38 is provided to temporarily release the slewing parking brake 30. The slewing release switch 38 is a switch that can be switched between at least two positions: an on position and an off position. Examples of the slewing release switch 38 include a seesaw switch, but it is not limited to this. The slewing release switch 38 is located on a console adjacent to the driver's seat or on a monitoring device.

[0023] The swivel release switch 38 has a first switching section 38a, a second switching section 38b, a third switching section 38c, and a fourth switching section 38d. The first switching section 38a, the second switching section 38b, the third switching section 38c, and the fourth switching section 38d are configured to switch in conjunction from the ON position to the OFF position and from the OFF position to the ON position. The first switching section 38a has an ON terminal 38a1, an OFF terminal 38a2, and a common terminal 38a3. The second switching section 38b has an ON terminal 38b1, an OFF terminal 38b2, and a common terminal 38b3. The third switching section 38c has an ON terminal 38c1, an OFF terminal 38c2, and a common terminal 38c3. The fourth switching section 38d has an ON terminal 38d1, an OFF terminal 38d2, and a common terminal 38d3.

[0024] The common terminal 38a3 of the first switching unit 38a is electrically connected to the battery 33. The ON terminal 38a1 of the first switching unit 38a is connected to the electrical connection line C2 that electrically connects the input terminal (first input terminal) T12 of the controller 10 to the second switching unit 38b. The OFF terminal 38a2 of the first switching unit 38a is electrically open. The first switching unit 38a switches between a conductive state and a non-conductive state between the battery 33 and the input terminal T12 of the controller 10. When the slewing release switch 38 is turned ON, the first switching unit 38a switches the battery 33 and the input terminal T12 of the controller 10 to a conductive state, and switches the battery 33 to a conductive state. When the slewing release switch 38 is turned OFF, the first switching unit 38a switches the battery 33 and the input terminal T12 of the controller 10 to a non-conductive state, and switches the battery 33 to a non-conductive state.

[0025] The second switching unit 38b is connected to the upstream terminal of the brake solenoid 32a. The second switching unit 38b is configured to switch the circuit connecting the upstream terminal of the brake solenoid 32a and the controller 10. The ON terminal 38b1 of the second switching unit 38b is electrically connected to the input terminal T12 of the controller 10 via the electrical connection line C2. That is, the ON terminal 38a1 of the first switching unit 38a and the ON terminal 38b1 of the second switching unit 38b are connected in parallel to the input terminal T12 of the controller 10. The OFF terminal 38b2 of the second switching unit 38b is electrically connected to the output terminal T11 of the controller 10 via the electrical connection line C1. The common terminal 38b3 of the second switching unit 38b is electrically connected to the upstream terminal of the brake solenoid 32a. The second switching unit 38b switches the connection between the upstream terminal of the brake solenoid 32a and the input terminal T12 of the controller 10, or the connection between the upstream terminal of the brake solenoid 32a and the output terminal T11 of the controller 10. When the swivel release switch 38 is turned ON, the second switching unit 38b switches the connection between the upstream terminal of the brake solenoid 32a and the input terminal T12 of the controller 10 to a conductive state, and switches the connection between the upstream terminal of the brake solenoid 32a and the output terminal T11 of the controller 10 to a non-conductive state. When the swivel release switch 38 is turned OFF, the second switching unit 38b switches the connection between the upstream terminal of the brake solenoid 32a and the input terminal T12 of the controller 10 to a non-conductive state, and switches the connection between the upstream terminal of the brake solenoid 32a and the output terminal T11 of the controller 10 to a conductive state.

[0026] The third switching unit 38c is configured to switch between a conductive state and a non-conductive state of the circuit connecting the ground 38G and the controller 10. The ON terminal 38c1 of the third switching unit 38c is electrically connected to the input terminal (second input terminal) T13 of the controller 10 via the electrical connection line C3. The OFF terminal 38c2 of the third switching unit 38c is electrically open. The common terminal 38c3 of the third switching unit 38c is electrically connected to the ground 38G. The third switching unit 38c switches between a conductive state and a non-conductive state between the input terminal T13 of the controller 10 and the ground 38G. When the slewing release switch 38 is turned ON, the third switching unit 38c switches the input terminal T13 of the controller 10 and the ground 38G to a conductive state, and switches the ground 38G and the fourth switching unit 38d to a conductive state. When the swivel release switch 38 is turned off, the third switching unit 38c switches the input terminal T13 of the controller 10 and ground 38G to a non-conductive state, and switches ground 38G and the fourth switching unit 38d to a non-conductive state.

[0027] The fourth switching unit 38d is configured to switch the circuit connecting the downstream terminal of the brake solenoid 32a and the controller 10. The ON terminal 38d1 of the fourth switching unit 38d is connected to the electrical connection line C3, which electrically connects the input terminal T13 of the controller 10 and the third switching unit 38c. That is, the ON terminal 38c1 of the third switching unit 38c and the ON terminal 38d1 of the fourth switching unit 38d are connected in parallel to the input terminal T13 of the controller 10. The OFF terminal 38d2 of the fourth switching unit 38d is electrically connected to the input terminal (third input terminal) T14 of the controller 10 via the electrical connection line C4. The common terminal 38d3 of the fourth switching unit 38d is electrically connected to the downstream terminal of the brake solenoid 32a. The fourth switching unit 38d switches the connection between the downstream terminal of the brake solenoid 32a and the input terminal T13 of the controller 10, or the connection between the downstream terminal of the brake solenoid 32a and the input terminal T14 of the controller 10. When the swing release switch 38 is turned ON, the fourth switching unit 38d switches the connection between the downstream terminal of the brake solenoid 32a and the input terminal T13 of the controller 10 to a conductive state, and switches the connection between the downstream terminal of the brake solenoid 32a and the ON terminal 38c1 of the third switching unit to a conductive state. It also switches the connection between the downstream terminal of the brake solenoid 32a and the input terminal T14 of the controller 10 to a non-conductive state. When the swing release switch 38 is turned OFF, the fourth switching unit 38d switches the connection between the downstream terminal of the brake solenoid 32a and the input terminal T13 of the controller 10 to a non-conductive state, and switches the connection between the downstream terminal of the brake solenoid 32a and the ON terminal 38c1 of the third switching unit to a non-conductive state. Furthermore, the downstream terminal of the brake solenoid 32a and the input terminal T14 of the controller 10 are switched to a conductive state.

[0028] Normally, the swivel release switch 38 is positioned in the off position. Specifically, the common terminal 38a3 of the first switching unit 38a is electrically connected to the off terminal 38a2, the common terminal 38b3 of the second switching unit 38b is electrically connected to the off terminal 38b2, the common terminal 38c3 of the third switching unit 38c is electrically connected to the off terminal 38c2, and the common terminal 38d3 of the fourth switching unit 38d is electrically connected to the off terminal 38d2. When the swivel release switch 38 is positioned in the off position, the output terminal T11 of the controller 10 is electrically connected to the upstream terminal of the brake solenoid 32a via the off terminal 38b2 and common terminal 38b3 of the second switching unit 38b. Furthermore, when the swivel release switch 38 is positioned in the off position, the downstream terminal of the brake solenoid 32a is electrically connected to the input terminal T14 of the controller 10 via the common terminal 38d3 and the off terminal 38d2 of the fourth switching unit 38d.

[0029] If the operator wants to allow the upper rotating body 2B to rotate freely, in other words, if the operator wants to temporarily and forcibly release the rotating parking brake 30, the operator operates the rotating release switch 38 to the ON position (ON operation). As a result, the common terminal 38a3 of the first switching unit 38a of the rotating release switch 38 is electrically connected to the ON terminal 38a1, the common terminal 38b3 of the second switching unit 38b is electrically connected to the ON terminal 38b1, the common terminal 38c3 of the third switching unit 38c is electrically connected to the ON terminal 38c1, and the common terminal 38d3 of the fourth switching unit 38d is electrically connected to the ON terminal 38d1.

[0030] When the swing release switch 38 is turned ON, the upstream terminal of the brake solenoid 32a is electrically connected to the battery 33 via the first switching unit 38a and the second switching unit 38b. The downstream terminal of the brake solenoid 32a is electrically connected to ground 38G via the third switching unit 38c and the fourth switching unit 38d. As a result, the brake solenoid 32a is driven by the voltage output from the battery 33, releasing the swing parking brake 30. At this time, the voltage from the battery 33 is input to the controller 10 via input terminal T12. The ground voltage of ground 38G is input to the controller 10 via input terminal T13. In this way, the swing release switch 38 has a redundant input to the controller 10.

[0031] [Swivel lock switch] The swivel lock switch (second switch) 36 is operated by the operator to engage or disengage the swivel parking brake 30. The swivel lock switch 36 is a switch that can be switched between at least two positions: an ON position and an OFF position. The swivel lock switch 36 is exemplified by, but is not limited to, a seesaw switch. The swivel lock switch 36 is electrically connected to the controller 10 via electrical connection wires C5 and C6.

[0032] The swivel lock switch 36 has a first switching section 36a and a second switching section 36b. The first switching section 36a and the second switching section 36b are configured to switch in conjunction with each other. The first switching section 36a has an ON terminal 36a1, an OFF terminal 36a2, and a common terminal 36a3. The second switching section 36b has an ON terminal 36b1, an OFF terminal 36b2, and a common terminal 36b3.

[0033] The first switching unit 36a is configured to switch between a conductive state and a non-conductive state of the circuit connecting the controller 10 and ground 36G1. The ON terminal 36a1 of the first switching unit 36a is electrically connected to the input terminal (fourth input terminal) T21 of the controller 10. The OFF terminal 36a2 of the first switching unit 36a is electrically open. The common terminal 36a3 of the first switching unit 36a is electrically connected to ground 36G1. The first switching unit 36a switches between a conductive state and a non-conductive state of the circuit connecting the input terminal T21 of the controller 10 and ground 36G1. When the swivel lock switch 36 is turned ON, the first switching unit 36a switches the input terminal T21 of the controller 10 and ground 36G1 to a conductive state. When the swivel lock switch 36 is turned OFF, the first switching unit 36a switches the input terminal T21 of the controller 10 and ground 36G1 to a non-conductive state.

[0034] The second switching unit 36b is configured to switch between a conductive state and a non-conductive state of the circuit connecting the controller 10 and ground 36G2. The ON terminal 36b1 of the second switching unit 36b is electrically open. The OFF terminal 36b2 of the second switching unit 36b is electrically connected to the input terminal (fifth input terminal) T22 of the controller 10. The common terminal 36b3 of the second switching unit 36b is electrically connected to ground 36G2. The second switching unit 36b switches between a conductive state and a non-conductive state of the circuit connecting the input terminal T22 of the controller 10 and ground 36G2. When the swivel lock switch 36 is turned ON, the second switching unit 36b switches the input terminal T22 of the controller 10 and ground 36G2 to a non-conductive state. When the swivel lock switch 36 is turned OFF, the second switching unit 36b switches the input terminal T22 of the controller 10 and ground 36G2 to a conductive state.

[0035] When the operator wants to stop and hold the upper slewing body 2B relative to the lower traveling body 2A, in other words, when the operator wants to engage the slewing parking brake 30, the operator turns on the slewing lock switch 36. As a result, the common terminal 36a3 of the first switching unit 36a of the slewing lock switch 36 is electrically connected to the ON terminal 36a1, and the common terminal 36b3 of the second switching unit 36b is electrically connected to the ON terminal 36b1. Consequently, when the slewing lock switch 36 is turned on, the input terminal T21 of the controller 10 is electrically connected to ground 36G1 via the first switching unit 36a, and the input terminal T22 of the controller 10 is electrically disconnected from ground 36G2 by the second switching unit 36b.

[0036] When the operator wants to allow the upper slewing body 2B to rotate freely relative to the lower traveling body 2A, in other words, when the operator wants to release the slewing parking brake 30, the operator manually operates the slewing lock switch 36 to the off position. As a result, the common terminal 36a3 of the first switching unit 36a of the slewing lock switch 36 is electrically connected to the off terminal 36a2, and the common terminal 36b3 of the second switching unit 36b is electrically connected to the off terminal 36b2. Consequently, when the slewing lock switch 36 is turned off, the input terminal T21 of the controller 10 is electrically disconnected from the ground 36G1 by the first switching unit 36a, and the input terminal T22 of the controller 10 is electrically connected to the ground 36G2 via the second switching unit 36b. In this way, the slewing lock switch 36 has a redundant input to the controller 10.

[0037] [controller] The controller 10 controls the brake solenoid 32a to engage or release the swivel parking brake 30 based on electrical signals from the swivel release switch 38 and the swivel lock switch 36. The controller 10 comprises a first switching element 12, a second switching element 13, and a swivel parking brake control unit 11.

[0038] The first switching element (connection circuit) 12 switches between a conductive state and a non-conductive state of the circuit that electrically connects the voltage applied from the battery to the brake solenoid 32a via the controller 10 to the output terminal T11. The first switching element 12 switches between a conductive state in which a voltage capable of operating the brake control valve 32 is applied to the swivel release switch 38 from the output terminal T11, and a non-conductive state in which no voltage is applied. The first switching element 12 is controlled based on commands from the control unit 111. The first switching element 12 is, for example, a FET (Field Effect Transistor) or a transistor. When the swivel release switch 38 is in the off position, if the first switching element 12 is controlled to be conductive, the upstream terminal of the brake solenoid 32a is electrically connected to the battery 33 via the controller 10. As a result, a voltage is applied from the battery 33 to the upstream terminal of the brake solenoid 32a. When the swivel release switch 38 is in the off position, and the first switching element 12 is controlled to be in a non-conductive state, the upstream terminal of the brake solenoid 32a is electrically disconnected from the battery 33. As a result, the voltage from the battery 33 to the upstream terminal of the brake solenoid 32a is cut off.

[0039] The second switching element (disconnection circuit) 13 switches between a conductive state and a non-conductive state of the circuit that electrically connects the input terminal T14 of the controller 10 and ground 13G. The second switching element 13 is controlled based on a command from the control unit 111. The second switching element 13 is, for example, an FET or a transistor. In this embodiment, the second switching element 13 is normally conductive when the controller 10 is started. When the swivel release switch 38 is in the off position, the downstream terminal of the brake solenoid 32a is electrically connected to ground 13G via the input terminal T14. When the swivel release switch 38 is in the off position, if the second switching element 13 is controlled to be non-conductive, the electrical connection between the downstream terminal of the brake solenoid 32a and ground 13G is disconnected.

[0040] The swivel parking brake control unit 11 controls the engagement and release of the swivel parking brake 30. The swivel parking brake control unit 11 comprises a detection unit 110 and a control unit 111.

[0041] The detection unit 110 detects an electrical signal from the swivel release switch 38. Because the controller 10 has redundant input from the swivel release switch 38, the detection unit 110 detects the electrical signal from the swivel release switch 38 via input terminals T12 and T13, respectively. When the swivel release switch 38 is turned ON, the detection unit 110 detects an electrical signal indicating the ON position via input terminals T12 and T13, respectively. When the swivel release switch 38 is turned OFF, the detection unit 110 detects an electrical signal indicating the OFF position via input terminals T12 and T13, respectively. In this embodiment, when the swivel release switch 38 is turned ON, the detection unit 110 detects the voltage from the battery 33 via input terminal T12 and the ground voltage of ground 38G via input terminal T13. This detection state of the detection unit is referred to as the first detection state. When the swivel release switch 38 is turned off, the detection unit 110 detects via input terminal T12 that the voltage from the battery 33 has been cut off, and via input terminal T13 that the ground voltage of ground 38G has been cut off. This detection state of the detection unit is referred to as the second detection state.

[0042] The detection unit 110 detects an electrical signal from the swivel lock switch 36. Because the input from the swivel lock switch 36 is duplicated in the controller 10, the detection unit 110 detects the electrical signal from the swivel lock switch 36 via input terminals T21 and T22, respectively. When the swivel lock switch 36 is turned ON, the detection unit 110 detects an electrical signal indicating the ON position via input terminals T21 and T22, respectively. When the swivel lock switch 36 is turned OFF, the detection unit 110 detects an electrical signal indicating the OFF position via input terminals T21 and T22, respectively. In this embodiment, when the swivel lock switch 36 is turned ON, the detection unit 110 detects the ground voltage of ground 36G1 via input terminal T21 and detects that the ground voltage of ground 36G2 is interrupted via input terminal T22. This detection state of the detection unit is referred to as the third detection state. When the swivel lock switch 36 is turned off, the detection unit 110 detects that the ground voltage of ground 36G1 is interrupted via input terminal T21 and detects the ground voltage of ground 36G2 via input terminal T22. This detection state of the detection unit is referred to as the fourth detection state.

[0043] The swivel parking brake control unit 11 controls the engagement and release of the swivel parking brake 30 based on inputs from input terminals T12, T13, T21, and T22. The control unit 111 controls at least one of the first switching element 12 and the second switching element 13 based on electrical signals from the swivel release switch 38 and the swivel lock switch 36 detected by the detection unit 110.

[0044] [Determining the position of the rotation release switch] The control unit 111 determines the position of the swivel release switch 38 based on the electrical signals from input terminals T12 and T13 detected by the detection unit 110. The control unit 111 determines whether the detection state based on input terminals T12 and T13 is a first detection state or a second detection state. If it is a first detection state, the control unit 111 determines that the swivel release switch 38 is in the ON position, and if it is a second detection state, the control unit 111 determines that the swivel release switch 38 is in the OFF position. If the control unit 111 determines that the swivel release switch 38 is in the OFF position, it controls the first switching element 12 based on the electrical signal from the swivel lock switch 36 detected by the detection unit 110.

[0045] [Determining the position of the swivel lock switch] The control unit 111 determines the position of the swivel lock switch 36 based on the electrical signals from input terminals T21 and T22 detected by the detection unit 110. The control unit 111 determines whether the detection state based on input terminals T21 and T22 is the third detection state or the fourth detection state. If it is the third detection state, the control unit 111 determines that the swivel lock switch 36 is in the ON position, and if it is the fourth detection state, the control unit 111 determines that the swivel lock switch 36 is in the OFF position. If the control unit 111 determines that the swivel lock switch 36 is in the ON position, it controls the first switching element 12 so that the external power supply located outside the controller 10 is electrically non-conductive with output terminal T11. As a result, no voltage is applied to the brake solenoid 32a via output terminal T11, and the swivel parking brake 30 is engaged. When the control unit 111 determines that the swivel lock switch 36 is in the off position, it controls the first switching element 12 so that the external power supply located outside the controller 10 becomes conductive with the output terminal T11. As a result, voltage is applied to the brake solenoid 32a via the output terminal T11, and the swivel parking brake 30 is released.

[0046] The control unit 111 determines an abnormality in the electrical circuit of the swivel parking brake system. An abnormality is, for example, a short circuit in the upstream circuit of the brake solenoid 32a, sticking of any of the switching parts of the swivel release switch 38, or sticking of any of the switching parts of the swivel lock switch 36. The control unit 111 determines the abnormality based on the electrical signals from the output terminal T11, the swivel release switch 38, and the swivel lock switch 36. If the control unit 111 determines an abnormality in the electrical circuit of the swivel parking brake system, it controls at least one of the first switching element 12 and the second switching element 13.

[0047] [Detection of abnormalities in the upstream circuit] The control unit 111 determines an abnormality in the upstream circuit of the brake solenoid 32a based on the electrical signal input to the detection unit 110 from the output terminal T11. For example, when the first switching element 12 is controlled to a non-conductive state, if the detection unit 110 detects a voltage from the input signal from the output terminal T11 that enables the brake solenoid 32a to operate, the control unit 111 determines that an abnormality such as a short circuit has occurred in the upstream circuit of the brake solenoid 32a. The voltage that enables the brake solenoid 32a to operate is, for example, the voltage from the battery. The voltage that enables the brake solenoid 32a to operate is, for example, 24V. If the control unit 111 determines that an abnormality has occurred in the upstream circuit of the brake solenoid 32a, it controls the second switching element 13 so that the downstream terminal of the brake solenoid 32a and the ground 13G are in a non-conductive state. Furthermore, if the control unit 111 determines that an abnormality has occurred in the upstream circuit of the brake solenoid 32a, it controls the first switching element 12 so that the voltage applied to the brake solenoid 32a via the controller 10 is cut off. As a result, the brake solenoid 32a of the brake control valve 32 does not drive, and the slewing parking brake 30 becomes engaged. Alternatively, if the control unit 111 determines that an abnormality has occurred in the upstream circuit of the brake solenoid 32a, it may control only the second switching element 13.

[0048] [Abnormal detection of the rotation release switch] The control unit 111 determines an abnormality in the swivel release switch 38 based on electrical signals input from input terminals T12 and T13. The control unit 111 determines that the swivel release switch 38 is in the ON position and normal if a voltage applied to the brake solenoid 32a is input from input terminal T12 and a ground voltage is input from input terminal T13. The control unit 111 determines that the swivel release switch 38 is in the OFF position and normal if there is no voltage input applied to the brake solenoid 32a from input terminal T12 and no ground voltage input from input terminal T13. If the inputs from input terminals T12 and T13 are other than those described above, the control unit 111 determines that an abnormality such as sticking has occurred in one of the first switching section 38a, second switching section 38b, third switching section 38c, and fourth switching section 38d of the swivel release switch 38. If the control unit 111 determines that an abnormality has occurred in the swivel release switch 38, it controls the first switching element 12 so that the voltage from the output terminal T11 to the brake solenoid 32a is cut off, regardless of the position of the swivel lock switch 36. Also, if the control unit 111 determines that an abnormality has occurred in the swivel release switch 38, it controls the second switching element 13 so that the downstream terminal of the brake solenoid 32a and the ground 13G become non-conductive. As a result, the brake solenoid 32a of the brake control valve 32 does not drive, and the swivel parking brake 30 becomes engaged.

[0049] [Detection of abnormality in the swivel lock switch] The control unit 111 detects an abnormality in the swivel lock switch 36 based on electrical signals input from input terminals T21 and T22. If a ground voltage is input simultaneously from input terminals T21 and T22, or if a ground voltage is not input simultaneously from input terminals T21 and T22, the control unit 111 determines, for example, that an abnormality such as sticking has occurred in either the first switching unit 36a or the second switching unit 36b of the swivel lock switch 36. If the control unit 111 determines that an abnormality has occurred in the swivel lock switch 36, it controls the first switching element 12 so that the voltage from the output terminal T11 of the controller 10 to the brake solenoid 32a is cut off. As a result, the brake solenoid 32a of the brake control valve 32 is not driven, and the swivel parking brake 30 is engaged. Furthermore, if the control unit 111 determines that an abnormality has occurred in the swivel lock switch 36, it may control the second switching element 13 so that the downstream terminal of the brake solenoid 32a and the ground 13G become non-conductive.

[0050] The control unit 111 controls the engagement and release of the slewing parking brake 30 based on the operation signal from the operating device 4. The conditions for releasing the slewing parking brake 30 are, for example, controlled so that the slewing parking brake 30 is released when the operating device for slewing is operated. When the operating device for slewing is operated to the neutral position, the slewing parking brake 30 is controlled to engage. The same control may also be applied when operating the operating devices of other work machines. When the control unit 112 detects an operation signal from the operating device 4, it controls the first switching element 12 so that a voltage is applied to the brake solenoid 32a.

[0051] [Computer System] Figure 3 is a block diagram showing a computer system 1000 according to an embodiment. The controller 10 described above includes the computer system 1000. The computer system 1000 has a processor 1001 such as a CPU (Central Processing Unit), a main memory 1002 including non-volatile memory such as ROM (Read Only Memory) and volatile memory such as RAM (Random Access Memory), a storage 1003, and an interface 1004 including input / output circuits. The functions of the 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 according to the program. The program may be distributed to the computer system 1000 via a network.

[0052] [Control processing for the swivel parking brake] Next, the processing procedure of the embodiment will be described with reference to the flowchart shown in Figure 4. Figure 4 is a flowchart showing the processing content performed by the controller 10 of the work machine 1 according to the embodiment.

[0053] The controller 10 detects an abnormality on the upstream side of the brake solenoid 32a (step ST11). More specifically, when the first switching element 12 is controlled so that the voltage applied to the brake solenoid 32a from the battery via the controller 10 and the output terminal T11 are in a non-conductive state, if the controller 10 detects a voltage from the output terminal T11 that would allow the brake solenoid 32a to operate, the controller 10 determines that an abnormality has occurred on the upstream side of the brake solenoid 32a. If the controller 10 determines that an abnormality has occurred on the upstream side of the brake solenoid 32a (Yes in step ST11), it proceeds to step ST17. If the controller 10 determines that no abnormality has occurred on the upstream side of the brake solenoid 32a (No in step ST11), it proceeds to step ST12.

[0054] If the controller determines that no abnormality has occurred upstream of the brake solenoid 32a (No in step ST11), the controller 10 detects an abnormality in the swivel release switch 38 (step ST12). The controller 10 determines the abnormality of the swivel release switch 38 based on the electrical signals input from input terminals T12 and T13. If the controller 10 determines that an abnormality has occurred in the swivel release switch 38 (Yes in step ST12), it proceeds to step ST17. If the controller 10 determines that no abnormality has occurred in the swivel release switch 38 (No in step ST12), it proceeds to step ST13.

[0055] If the controller determines that there is no abnormality in the slewing release switch 38 (No in step ST12), the controller 10 detects an abnormality in the slewing lock switch 36 (step ST13). The controller 10 determines the abnormality of the slewing lock switch 36 based on the electrical signals input from input terminals T21 and T22. If the controller 10 determines that an abnormality has occurred in the slewing lock switch 36 (Yes in step ST13), it proceeds to step ST18. If the controller 10 determines that there is no abnormality in the slewing lock switch 36 (No in step ST13), it proceeds to step ST15.

[0056] If the controller determines that there is no abnormality in the swivel lock switch 36 (No in step ST13), the controller 10 determines whether the conditions for releasing the swivel lock have been met (step ST15). The controller 10 determines that the conditions for releasing the swivel lock have been met if the swivel lock switch 36 is in the off position and an operation signal from the operating device 4 is detected. The controller 10 determines that the conditions for releasing the swivel lock have not been met if the swivel lock switch 36 is in the on position or if no operation signal from the operating device 4 is detected. If the controller 10 determines that the conditions for releasing the swivel lock have been met (Yes in step ST15), it proceeds to step ST19. If the controller 10 determines that the conditions for releasing the swivel lock have not been met (No in step ST15), it proceeds to step ST16.

[0057] If it is determined that the conditions for releasing the swivel lock are not met (No in step ST15), the controller 10 cuts off the voltage to the upstream terminal of the brake solenoid 32a (step ST16). As a result, the swivel parking brake 30 remains engaged, and the upper swivel body 2B is held in a stopped position.

[0058] If the controller 10 determines that an abnormality has occurred upstream of the brake solenoid 32a (Yes in step ST11), or if it determines that an abnormality has occurred in the swing release switch 38 (Yes in step ST12), the controller 10 cuts off the voltage to the upstream terminal of the brake solenoid 32a, and makes the downstream terminal of the brake solenoid 32a and the ground 13G non-conductive (step ST17). As a result, the swing parking brake 30 remains engaged, and the upper swing body 2B is stopped and held.

[0059] If the controller determines that an abnormality has been detected in the swivel lock switch 36 (Yes in step ST13), the controller 10 cuts off the voltage to the upstream terminal of the brake solenoid 32a (step ST18). As a result, the swivel parking brake 30 remains engaged, and the upper swivel body 2B is held in a stopped position.

[0060] If the controller determines that the conditions for releasing the slewing lock are met (Yes in step ST15), the controller 10 outputs a voltage to the upstream terminal of the brake solenoid 32a (step ST19). As a result, the slewing parking brake 30 is released, and the upper slewing body 2B becomes able to rotate.

[0061] [effect] As described above, this embodiment includes a lower traveling body 2A, an upper rotating body 2B rotatably positioned relative to the lower traveling body 2A, a rotating parking brake 30 that stops the rotation of the upper rotating body 2B relative to the lower traveling body 2A, a brake control valve 32 that controls the engagement and release of the rotating parking brake 30, a rotating release switch 38 that accepts an operation to release the rotating parking brake 30, and a controller 10. The controller 10 includes a first input terminal T12 and a second input terminal T13 connected to the rotating release switch 38, an output terminal T11 electrically connected to the upstream terminal of the brake control valve 32 via the rotating release switch 38, and a first switching element 12 that switches between a conductive state in which a voltage capable of operating the brake control valve 32 is applied to the rotating release switch 38 from the output terminal T11, and a non-conductive state in which no voltage is applied. The controller 10 controls the first switching element 12 based on the inputs from the first input terminal T12 and the second input terminal T13. In this embodiment, the input from the swing release switch 38 to the controller 10 is duplicated, so that an abnormality in the swing release switch 38 can be detected and the first switching element 12 can be controlled. According to this embodiment, the swing parking brake 30 can be operated more reliably.

[0062] In this embodiment, the controller 10 further includes a third input terminal T14 and a second switching element 13. The controller 10 can control the second switching element 13 based on inputs from the first input terminal T12 and the second input terminal T13. According to this embodiment, the swivel parking brake 30 can be operated more reliably.

[0063] In this embodiment, when the controller 10 detects a voltage from the output terminal T11 while the first switching element 12 is in a non-conductive state, it can control the second switching element 13 to become non-conductive. This allows the controller 10 to engage the slewing parking brake 30 when it detects an abnormality. According to this embodiment, the slewing parking brake 30 can be operated more reliably.

[0064] In this embodiment, the first switching section 38a, the second switching section 38b, the third switching section 38c, and the fourth switching section 38d of the swivel release switch 38 can be switched in conjunction with each other.

[0065] In this embodiment, the controller 10 can control the first switching element 12 based on inputs from the fourth input terminal T21 and the fifth input terminal 15.

[0066] In this embodiment, the swivel lock switch 36 has a first switching unit 36a that switches between a conductive state and a non-conductive state between the fourth input terminal T21 and ground, and a second switching unit 36b that switches between a conductive state and a non-conductive state between the fifth input terminal T22 and ground. In this embodiment, the first switching unit 36a and the second switching unit 36b of the swivel lock switch 36 can be switched in conjunction with each other.

[0067] In this embodiment, the brake solenoid 32a is an electromagnetic solenoid, which releases the slewing parking brake 30 when energized and activates the slewing parking brake 30 when demagnetized.

[0068] In this embodiment, we have described a work machine 1 having a hydraulic swing motor, but we are not limited to this, and the invention can also be applied to work machines in which the swing motor is an electric motor. [Explanation of Symbols]

[0069] 1...Work machine, 2A...Lower traveling body, 2B...Upper slewing body, 3...Hydraulic slewing motor, 3a...Drive shaft, 4...Operating device, 5...Power source, 8...Hydraulic pump, 8a...Discharge oil passage, 10...Controller, 11...Slewing parking brake control unit, 12...First switching element (connection circuit), 13...Second switching element (disconnection circuit), 30...Slewing parking brake (slewing braking device), 31...Brake cylinder, 31a...Rod, 31b...Oil chamber, 32...Brake control valve (actuator), 32a...Brake solenoid, 33...B T11... 36... Swivel lock switch (second switch), 36a... First switching section, 36b... Second switching section, 38... Swivel release switch (first switch), 38a... First switching section, 38b... Second switching section, 38c... Third switching section, 38d... Fourth switching section, 40... Valve, 41, 42, 43... Hydraulic cylinder, T11... Output terminal, T12... Input terminal (first input terminal), T13... Input terminal (second input terminal), T14... Input terminal (third input terminal), T21... Input terminal (fourth input terminal), T22... Input terminal (fifth input terminal).

Claims

1. Lower running body and An upper slewing body is arranged to be rotatable relative to the lower traveling body, A slewing braking device that stops the slewing of the upper slewing body relative to the lower traveling body, An actuator that controls the engagement and disengagement of the slewing brake device, A first switch that accepts an operation to release the aforementioned slewing brake device, Controller and Equipped with, The aforementioned controller, The first input terminal and the second input terminal connected to the first switch, An output terminal electrically connected to the upstream terminal of the actuator via the first switch, The system includes a connection circuit that switches between a conductive state, where a voltage capable of operating the actuator is applied to the first switch from the output terminal, and a non-conductive state, where no voltage is applied. Based on the inputs from the first input terminal and the second input terminal, the connection circuit is controlled. A type of machinery used for industrial work.

2. The aforementioned controller, A third input terminal is electrically connected to the downstream terminal of the actuator via the first switch, The device includes a circuit breaker that switches the electrical connection between the third input terminal and ground between a conductive state and a non-conductive state, Based on the inputs from the first input terminal and the second input terminal, the cutoff circuit is controlled. The work machine according to claim 1.

3. The aforementioned controller, When the voltage is detected from the output terminal while the connection circuit is in a non-conductive state, the circuit breaker is controlled to be in a non-conductive state. The working machine according to claim 2.

4. The first switch is, A first switching unit that switches between a conductive state and a non-conductive state between the battery and the first input terminal of the controller, A second switching unit that switches the connection between the upstream terminal of the actuator and the first input terminal of the controller, or the connection between the output terminal of the controller and the upstream terminal of the actuator, A third switching unit that switches between a conductive state and a non-conductive state between the second input terminal of the controller and ground, The system includes a fourth switching unit that switches the connection between the downstream terminal of the actuator and the second input terminal of the controller, or the connection between the downstream terminal of the actuator and the third input terminal, The first switching section, the second switching section, the third switching section, and the fourth switching section of the first switch are configured to switch in conjunction with each other. The working machine according to claim 2.

5. The vehicle is equipped with a second switch that receives an operation to engage and disengage the aforementioned slewing braking device. The aforementioned controller, It comprises a fourth input terminal and a fifth input terminal connected to the second switch, Based on the inputs from the fourth and fifth input terminals, the connection circuit is controlled. The work machine according to claim 1.

6. The second switch is, A first switching unit that switches between a conductive state and a non-conductive state between the fourth input terminal and ground, It has a second switching unit that switches between a conductive state and a non-conductive state between the fifth input terminal and ground, The first switching unit of the second switch and the second switching unit are configured to switch in conjunction with each other. The working machine according to claim 5.

7. The actuator is an electromagnetic solenoid, which, when energized, releases the slewing brake device, and when demagnetized, engages the slewing brake device. The work machine according to claim 1.

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