Work equipment

Abstract

The goal is to reduce the number of parts and costs, while also improving safety. [Solution] The system includes a control valve 60D that controls the supply and discharge of hydraulic fluid, a first oil passage L6 that connects the control valve 60D to the first hydraulic actuator 30a, a branch oil passage that branches off from the first oil passage L6 and can be connected to a connecting hydraulic actuator 80, an on-off valve 63 that is located on the side of the branch of the first oil passage L6 to the first hydraulic actuator 30a and controls the opening and closing of the first oil passage L6, and a connecting control valve 64 that controls the opening and closing of the branch oil passage L15. The system is switchable between a first state in which the on-off valve 63 is in an open state and the connecting control valve 64 is in a closed state, supplying hydraulic fluid from the control valve 63 to the first hydraulic actuator 30a, and a second state in which the on-off valve 63 is in a closed state and the connecting control valve 64 is in an open state, supplying hydraulic fluid from the control valve 60D to the connecting hydraulic actuator 80.

Description

Technical Field

[0004] ,

[0001] The present invention relates to a working machine to which a connecting attachment for detachable working attachments can be attached.

Background Art

[0002] Conventionally, a working machine to which a connecting attachment equipped with a hydraulic actuator for detachable working attachments can be attached is known. (For example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, if a dedicated supply source is provided as a supply source of hydraulic oil supplied to the hydraulic actuator of the connecting attachment, an increase in the number of parts and an increase in cost will occur. Therefore, it is conceivable to use the hydraulic oil supplied to other hydraulic actuators. However, in that case, there is a risk that other actuators will operate contrary to the intention of the operator when the hydraulic actuator of the connecting attachment operates.

[0005] Therefore, an object of the present invention is to reduce the number of parts and cost and improve safety in a working machine to which a hydraulically driven connecting attachment can be mounted.

Means for Solving the Problems

[0006] The present invention relates to a work machine having an attachment mounting portion to which a connecting attachment can be attached, which includes a connecting hydraulic actuator that can be switched between a connected state in which a work attachment is connected and a disconnected state in which the connection of the work attachment is released. The machine includes a control valve for controlling the supply and discharge of hydraulic fluid, a first oil passage connecting the control valve and a first hydraulic actuator, a branch oil passage branching from the first oil passage and connectable to the connecting hydraulic actuator, an on-off valve provided on the first hydraulic actuator side of the branch portion of the first oil passage with the branch oil passage and for opening and closing the first oil passage, and a connecting control valve for opening and closing the branch oil passage. The machine is switchable between a first state in which the on-off valve is in an open state and the connecting control valve is in a closed state, supplying hydraulic fluid from the control valve to the first hydraulic actuator, and a second state in which the on-off valve is in a closed state and the connecting control valve is in an open state, supplying hydraulic fluid from the control valve to the connecting hydraulic actuator. [Effects of the Invention]

[0007] According to the present invention, in a work machine that can be fitted with a hydraulically driven connecting attachment, it is possible to reduce the number of parts and costs, while also improving safety. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view from the front of a work machine according to one embodiment of the present invention. [Figure 2] Figure 2 is an exploded perspective view of the work machine according to the same embodiment, seen from the front. [Figure 3] Figure 3 is a cross-sectional view of a connecting attachment that is attached to the attachment mounting section of a work machine according to the same embodiment. [Figure 4] Figure 4 is a schematic side view of the attachment mounting section of the work machine according to the same embodiment and the bucket, which is a work attachment. [Figure 5] Figure 5 is a schematic side view of the attachment mounting section of the work machine and the breaker, which is a work attachment, according to the same embodiment. [Figure 6] Figure 6 is a diagram showing the state of a part of the system that operates the connecting attachment of the hydraulic system of the work machine according to the same embodiment, and is a diagram showing the state when the connection between the connecting attachment and the work attachment is released. [Figure 7] Figure 7 is a diagram showing the state of a part of the system that operates the connecting attachment of the hydraulic system of the work machine according to the same embodiment, and is a diagram showing the state when the connecting attachment and the work attachment are connected. [Figure 8] Figure 8 is a block diagram of the control device for the work machine according to the same embodiment. [Modes for carrying out the invention]

[0009] (1-1. Overall Structure) One embodiment of the present invention will be described below. In this embodiment, the case in which the present invention is applied to a backhoe will be described, but it is not limited to this. The present invention can be applied to any work machine to which a work attachment can be detachably attached, and can be applied to construction machinery such as compact track loaders, skid rollers, and wheel loaders, or agricultural machinery such as tractors.

[0010] In the following explanation, the forward direction of the work machine is referred to as "forward," the backward direction as "rearward," the right side when facing forward is referred to as "rightward," and the left side when facing forward is referred to as "leftward."

[0011] As shown in Figures 1 and 2, the work machine 1 comprises left and right traveling devices 4, a machine body 2 rotatably supported on the traveling devices 4, and work devices 3a and 3b supported on the machine body 2.

[0012] Furthermore, as shown in Figure 2, the work machine 1 includes an operating unit 22 for the operator to operate the work devices 3a and 3b (a left operating lever 22a for rotating the turntable 21, a right operating lever 22b for operating the shovel device 3b, which is the work device 3b and will be described later, a dozer operating lever 22c for operating the dozer device 3a, which is the work device 3a and will be described later), a travel lever 22d for operating the travel device 4, operating switches 23 and 24 (first operating switch 23, second operating switch 24) for operations related to the supply of hydraulic fluid to the AUX port (hydraulic fluid outlet port) 61 that can supply hydraulic fluid to the external hydraulic equipment (work attachment) 9 equipped with the first hydraulic actuator 90, a monitor 26 for displaying various information, and a control device 5 for controlling the travel device 4 and the work devices 3a and 3b, etc.

[0013] The machine body 2 comprises a travel base 20 connecting the left and right travel devices 4, and a turntable 21 rotatably supported on the travel base 20. The turntable 21 is equipped with a driver's seat DS where the operator sits, an operating unit 22 (left operating lever 22a, right operating lever 22b, dozer operating lever 22c, travel lever 22d) for the operator to operate the work devices 3a and 3b, a coupling operation switch 25, a monitor 26, a driver's seat protection device 27 to protect the driver's seat DS (operator), etc. The coupling operation switch 25 is an ON-OFF switch for operating the coupling attachment 8 (so-called quick coupler) described later. In this embodiment, the coupling operation switch 25 is located at the tip of the dozer operating lever 22c, but it is not limited to this and may be located in other positions.

[0014] The left operating lever 22a and the right operating lever 22b can be tilted forward, backward, left, and right. The left operating lever 22a controls the rotation of the machine body 2 (turntable 21) according to the direction and amount of tilt, and the right operating lever 22b controls the operation of the work device 3b according to the direction and amount of tilt. The dozer operating lever 22c can swing back and forth and controls the raising and lowering of the work device (dozer device) 3a according to the swing position. That is, the dozer operating lever 22c of the operating unit 22 operates the control valve (lifting cylinder control valve) 60D, which will be described later, according to the content of the operation, and changes the flow rate of the hydraulic fluid supplied from the control valve 60D. A pair of travel levers 22d are provided corresponding to the left and right travel devices 4, and swinging them in the back and forth direction controls the forward and reverse (reverse) movement of the travel devices 4. As will be described in detail later, in this embodiment the dozer operating lever 22c can also be used to operate the connecting attachment 8, which will be described later.

[0015] The work machine 1 of this embodiment is equipped with two work devices 3a and 3b. One of the work devices 3a is a dozer device equipped with a lifting arm 31a pivotally supported on a travel base 20 so as to be able to swing around a horizontal axis, and a blade (dozer blade) 32a attached to the tip of the lifting arm 31a. The lifting arm 31a moves up and down around the horizontal axis by the extension and retraction of a lifting hydraulic actuator (hereinafter referred to as a lifting cylinder) 30a, which is a first hydraulic actuator.

[0016] The other work device 3b includes a boom 34b that is rotatable (swings) around a vertical axis and rotatable around a first horizontal axis S1 relative to the slewing platform 21, an arm 35b that is rotatable around a second horizontal axis S2 at the tip of the boom 34b, and a connecting attachment 8 (see Figure 3) that is detachably attached to an attachment mounting portion 36b provided at the tip of the arm 35b. Accordingly, the work machine 1 includes, as a first hydraulic actuator for operating the other work device 3b, a swing cylinder for swinging the boom 34b, a boom cylinder 30b for rotating the boom 34b around the horizontal axis S1, an arm cylinder 31b for rotating the arm 35b around the horizontal axis S2, and a work tool cylinder 32b for rotating the attachment mounting portion 36b around the horizontal axis S3.

[0017] The attachment 8 for connection is for attachably mounting the working attachment 9 to the working device 3b by hydraulic operation. As the working attachment 9, for example, a bucket (see FIG. 4), a hydraulic crusher, a hydraulic breaker (see FIG. 5), an angle bloom, an earth auger, a pallet fork, a sweeper, a mower, a snow blower, etc. can be attached.

[0018] (1-2. Structure of the attachment 8 for connection) FIG. 3 is a longitudinal sectional view of the attachment 8 for connection. As shown in FIG. 3, the attachment 8 for connection includes a connecting portion 81 connected to the attachment mounting portion 36b of the working device 3b, and a connecting hydraulic actuator 80 that switches between a connected state in which the working attachment 9 is connected and a disconnected state in which the connection of the working attachment 9 is released.

[0019] The attachment mounting portion 36b of the working device 3b includes a link body 361 that connects the rod end of the working tool cylinder 32b and the connecting portion 81 of the attachment 8 for connection. This link body 361 is connected to the rod end of the working tool cylinder 32b by a shaft that is concentric (the same) with the shaft that connects another link body connecting the arm 35b and the working tool cylinder 32b and the rod end of the working tool cylinder 32b. The connecting portion 81 of the attachment 8 for connection is connected to the tip of the link body 361 and the tip of the arm 35b via shafts S3 and S4 that extend in the lateral direction, respectively.

[0020] The connecting attachment 8 has a connecting portion 81 that is connected to the attachment mounting portion 36b. The connecting portion 81 of the connecting attachment 8 is positioned to overlap laterally with the attachment mounting portion 36b (the tip of the link body 361 and the tip of the arm 35b), and the attachment can be connected to and disconnected from the attachment mounting portion 36b by inserting and removing shafts S3 and S4 into holes H1 and H2 provided in this overlapping portion. In other words, the connecting portion 81 of the connecting attachment 8, the tip of the link body 361, and the tip of the arm 35b (attachment mounting portion 36b) are provided with holes H1 and H2 that penetrate laterally. By inserting shafts S3 and S4 through the holes H1 and H2 so as to span the connecting portion 81 and the attachment mounting portion 36b, the connecting attachment 8 (connecting portion 81) is rotatably connected around the shaft S3 (hereinafter referred to as the third horizontal shaft S3) inserted through the hole H1 at the tip of the arm 35b.

[0021] The connecting attachment 8 comprises a first body 82 having a first shaft fitting portion 820 into which one of the two shafts S5, S5 provided on the connecting portion 91 of the work attachment 9 can be fitted; a fall prevention piece 83 for preventing the shaft S5 fitted into the first shaft fitting portion 820 from falling out; and a second body 84 having a second shaft fitting portion 840 into which the other shaft S5 of the two shafts S5, S5 can be fitted.

[0022] The first shaft fitting portion 820 and the second shaft fitting portion 840 are recesses that open laterally, allowing the shaft to be fitted through these openings. The first shaft fitting portion 820 and the second shaft fitting portion 840 open in opposite directions (reverse directions). The second body 84 is indirectly rotatably connected to the first body 82.

[0023] Specifically, the second body 84 is rotatably mounted around an axis S4 that connects the connecting portion 81 and the second link body 361, and is connected to the first body 82 via the connecting portion 81. As a result, the distance between the first shaft fitting portion 820 and the second shaft fitting portion 840 is changed by the relative rotation of the first body 82 and the second body 84 around axis S4. Specifically, the distance between the first shaft fitting portion 820 and the second shaft fitting portion 840 is configured to be switchable between a distance narrower than the distance between the two shafts S5, S5 fixed to the connecting portion 91 of the work attachment 9, and a distance in which both the two shafts S5, S5 fixed to the connecting portion 91 of the work attachment 9 are in a fitted state.

[0024] The anti-detachment piece 83 is provided so as to be able to extend and retract from the open portion of the first shaft fitting portion 820. In this embodiment, the anti-detachment piece 83 is fixed to the first body 82 via a support shaft S6 that extends laterally. That is, the anti-detachment piece 83 is provided so as to be able to rotate around the support shaft S6, and by rotating around the support shaft S6, it switches between a state in which it extends into the open portion of the first shaft fitting portion 820 and a state in which it is retracted from the open portion of the first shaft fitting portion 820.

[0025] Accordingly, the connecting attachment 8 has a connecting hydraulic actuator 80 that rotates the anti-detachment piece 83 and the second body 84. In this embodiment, the connecting hydraulic actuator 80 is a hydraulic cylinder that can extend and retract in a uniaxial direction and is positioned across the second body 84 and the anti-detachment piece 83. In this embodiment, the connecting hydraulic actuator 80 is a single-acting hydraulic cylinder that shortens when hydraulic fluid is supplied and extends when hydraulic fluid is discharged.

[0026] Specifically, the connecting hydraulic actuator 80 (hydraulic cylinder) includes a cylindrical cylinder body 800, a piston rod 801 including a piston 801a that is housed within the cylinder body 800 so as to be movable in the axial direction and a rod 801b that is continuous with the piston 801a and protrudes from one end of the cylinder body 800, and a coil spring 802 housed within the other end of the cylinder body 800 that biases the piston 801a toward one side of the cylinder body 800. One end of the cylinder body 800 is provided with a port for inflowing and outflowing hydraulic fluid, which is a port for connecting piping.

[0027] In the connecting hydraulic actuator 80, the tip (rod end) of the rod 801b is connected to the second body 84 via a laterally extending shaft S7, and the other end (cylinder end) of the cylinder body 800 is connected to the anti-detachment piece 83 via a laterally extending shaft S8. The connection position between the connecting hydraulic actuator 80 (hydraulic cylinder) and the anti-detachment piece 83 is set to an eccentric position with respect to the rotation center (pivot shaft S6) of the anti-detachment piece 83.

[0028] In the case of the connecting hydraulic actuator 80, when no hydraulic fluid is supplied to the port, the piston 801a is pushed towards one end of the cylinder body 800 by the biasing force of the coil spring 802, resulting in an extended state. When hydraulic fluid is supplied to the port, the piston 801a is pushed against the biasing force of the coil spring 802 towards the other end of the cylinder body 800, resulting in a shortened state. As a result, in this embodiment, the connecting hydraulic actuator 80 can release the connection of the work attachment 9 when hydraulic fluid is supplied from the control valve 60D, and maintains the connection of the work attachment 9 when hydraulic fluid is not supplied from the control valve 60D (good biasing force of the coil spring 802).

[0029] When the connecting hydraulic actuator 80 is extended, the anti-detachment piece 83 widens the gap between the first shaft fitting portion 820 and the second shaft fitting portion 840, and the shafts S5, S5 of the work attachment 9 engage with the first shaft fitting portion 820 and the second shaft fitting portion 840, allowing the work attachment 9 to be attached to the connecting attachment 8. On the other hand, when the connecting hydraulic actuator 80 is retracted, the gap between the first shaft fitting portion 820 and the second shaft fitting portion 840 narrows, allowing the shaft S5 to be inserted into and removed from the first shaft fitting portion 820 through the open portion of the first shaft fitting portion 820. As a result, the work attachment 9 is removed from the connecting attachment 8.

[0030] Figures 6 and 7 are explanatory diagrams showing the hydraulic circuit for driving the connecting attachment 8, with Figure 6 showing the unconnected state and Figure 7 showing the connected state. The work machine 1 includes a hydraulic pump (not shown) that draws up and discharges hydraulic fluid from the hydraulic fluid tank T, and a plurality of control valves 60D that control the supply and discharge of hydraulic fluid to the first hydraulic actuators 30a, 30b, 31b, and 32b that operate the work devices 3a and 3b. In this embodiment, the plurality of control valves are integrated together to form a control valve unit. Note that in Figures 6 and 7, only the control valve 60D that controls the supply and discharge of hydraulic fluid to the lifting cylinder 30a, which is a lifting hydraulic actuator that operates the dozer device 3a (hereinafter referred to as the lifting cylinder control valve) is shown among the plurality of control valves.

[0031] Accordingly, the pair of supply and discharge ports of the lifting cylinder control valve 60D, which controls the supply and discharge of fluid to and from the lifting cylinder 30a, are connected to the rod side and head side of the lifting cylinder 30a, respectively, via the first oil passage L6. The lifting cylinder control valve 60D can be switched between a neutral position, where the hydraulic fluid from the hydraulic pump flows downstream without supplying it to the lifting cylinder 30a; a first position, where the hydraulic fluid from the hydraulic pump is supplied to the rod side of the lifting cylinder 30a; and a second position, where the hydraulic fluid from the hydraulic pump is supplied to the head side of the lifting cylinder 30a. In addition, each first oil passage L6 is provided with an on-off valve 63 that opens and closes each first oil passage L6. The on-off valve 63 is a solenoid valve and opens and closes the first oil passage L6 according to the instructions of the control device 5, which will be described later.

[0032] Furthermore, one of the first oil passages L6 connecting the lifting cylinder control valve 60D and the lifting cylinder 30a (in this embodiment, the first oil passage L6 connected to the rod side of the lifting cylinder 30a) is connected to a branch oil passage L15 that is connected to a connecting hydraulic actuator 80 via a connecting control valve 64. The branch oil passage L15 is also provided with a connecting control valve 64 that opens and closes the branch oil passage L15. The connecting control valve 64 is a solenoid valve and, according to the instructions of the control device 5 described later, is switched between a supply position (disconnection position) that supplies hydraulic fluid supplied from the lifting cylinder control valve 60D via the first oil passages L6 and L15 to the connecting control valve 64 and a shut-off position (connection position) that shuts off the supply to the connecting control valve 64. Furthermore, the connecting control valve 64 is connected to the hydraulic oil tank T via a return oil passage L16. In the supply position, it shuts off the return oil passage L16 connecting the connecting hydraulic actuator 80 and the hydraulic oil tank T, and in the shut-off position, it connects the connecting hydraulic actuator 80 and the hydraulic oil tank T.

[0033] (1-3. Operation of the connecting attachment 8) As shown in Figure 8, the control device 5 is a so-called ECU (Electronic Control Unit) and comprises a calculation control unit 50, a storage unit 51 that stores information used in the processing of the calculation control unit 50, an input unit 52 that receives input information from the outside, and an output unit 53 that outputs output signals from the calculation control unit 50 to the outside. The input unit 52 receives signals corresponding to operations on the operation unit 22 (left operation lever 22a, right operation lever 22b, dozer operation lever 22c, travel lever 22d) and the coupling operation switch 25, as well as signals from various sensors (pressure detection sensor, angle sensor, etc.) provided on the work machine 1. The output unit 53 outputs signals for controlling the operation of various parts of the work machine 1 (various hydraulic actuators, monitor 26, lighting device, sound output device, air conditioning device, etc.).

[0034] The work machine 1 (control device 5) switches between a first state in which the on-off valve 63 is open and the connecting control valve 64 is closed, supplying hydraulic fluid from the lifting cylinder control valve 60D to the first hydraulic actuator 30a, and a second state in which the on-off valve 63 is closed and the connecting control valve 64 is open, supplying hydraulic fluid from the lifting cylinder control valve 60D to the connecting hydraulic actuator 80. In this embodiment, when an operator operates the connecting operation switch 25, a signal corresponding to the operation is input to the control device 5. The control device 5 operates the on-off valve 63 and the connecting control valve 64 in response to the operation of the connecting operation switch 25. Note that the connecting operation switch 25 may be made operable only when the work machine 1 is in a predetermined state (for example, when the traveling device 4 is not driven and the blade 32a of the work device 3a is positioned to correspond to the neutral position of the dozer operation lever 22c), and the control device 5 may not operate the on-off valve 63 and the connecting control valve 64 even if the connecting operation switch 25 is operated when the work machine 1 is not in a predetermined state.

[0035] Specifically, when the coupling operation switch 25 is turned ON, the control device 5 operates the on-off valve 63 to the closed position and the coupling control valve 64 to the open position (to the second state). In other words, when the coupling operation switch 25 is turned ON, the control device 5 operates the on-off valve 63 to the closed position and operates the coupling control valve 64 to the supply position (coupling release position) (to the second state). At this time, the control device 5 may display on the monitor 26 that the coupling attachment 8 is in operation mode, or provide an audible notification.

[0036] With the on-off valve 63 closed and the connecting control valve 64 in the supply position (disconnection position), when the operator operates the dozer operating lever 22c, the lifting cylinder control valve 60D operates in response to the lever operation, and hydraulic fluid flows from the outlet port of the lifting cylinder control valve 60D into the first oil passage L6. However, the hydraulic fluid heading towards the lifting cylinder 30a is blocked by the on-off valve 63 and supplied to the connecting hydraulic actuator 80 via the branch oil passage L15 and the connecting control valve 64. As a result, hydraulic fluid is supplied to one end of the cylinder body 800 in the connecting hydraulic actuator 80, pushing the piston 801a to the other end and shortening the connecting hydraulic actuator 80 (hydraulic cylinder). Consequently, the anti-detachment piece 83 and the second body 84 rotate, the anti-detachment piece 83 retracts from the engagement position, and the shaft S5 in the connecting portion 91 of the work attachment 9 disengages from the first shaft fitting portion 820 and the second shaft fitting portion 840.

[0037] Furthermore, in this embodiment, when the coupling operation switch 25 is turned OFF, the control device 5 operates the on-off valve 63 to the open position and operates the coupling control valve 64 to the shut-off position (coupling position) (to the first state). When attaching the work attachment 9, the worker first operates the work device 3b to position the first shaft fitting portion 820 and the second shaft fitting portion 840 of the coupling attachment 8 so that they can be fitted onto the shaft S5 of the coupling portion 91 of the work attachment 9, and then turns the coupling operation switch 25 OFF.

[0038] As a result, the hydraulic fluid from the lifting cylinder control valve 60D is shut off by the connecting control valve 64 and is no longer supplied to the connecting hydraulic actuator 80, and the hydraulic fluid in the connecting hydraulic actuator 80 is discharged from the return oil passage L16 to the hydraulic fluid tank T. Consequently, the piston 801a of the connecting hydraulic actuator 80 is biased toward one end of the cylinder body 800 by the coil spring 802, causing the piston 801a to extend, and the shafts S5, S5 of the work attachment 9 are fitted into the first shaft fitting part 820 and the second shaft fitting part 840, connecting the work attachment 9 to the connecting attachment 8. Furthermore, when the connecting operation switch 25 is turned OFF, the on / off valve 63 opens, making the lifting cylinder 30a of the dozer device 3a operable.

[0039] In this embodiment, the connecting attachment 8 has a first shaft fitting portion 820 and a fall prevention piece 83, and the shaft S5 of the connecting portion 91 of the work attachment 9 is held by the combination of the first shaft fitting portion 820 and the fall prevention piece 83. However, the invention is not limited to this. For example, the connecting attachment 8 may be equipped with a hydraulic cylinder as a connecting hydraulic actuator 80, and the rod (piston rod) of the hydraulic cylinder or a shaft connected to the rod may be provided to be insertable and detachable into the hole of the connecting portion 91 of the work attachment 9. Furthermore, the connecting hydraulic actuator 80 is not limited to a single-acting hydraulic cylinder; a double-acting hydraulic cylinder or a hydraulic motor may also be used.

[0040] Furthermore, in this embodiment, the branch oil passage L15 is branched from the first oil passage L6 that supplies hydraulic fluid to the lifting cylinder 30a of the dozer device 3a, but it is not limited to this. That is, the branch oil passage L15 is branched from the first oil passage L6 that is connected to the lifting cylinder control valve 60D, but it is not limited to this. For example, an AUX port (hydraulic fluid outlet port) 61 capable of supplying hydraulic fluid to an external hydraulic device equipped with a hydraulic actuator may be provided, and the branch oil passage L15 may be branched from the oil passage that supplies hydraulic fluid to the AUX port 61 from a control valve that controls the supply and discharge of hydraulic fluid to the AUX port 61. Alternatively, a branched oil passage L15 may be branched from the oil passage connecting a plurality of first hydraulic actuators 30b, 31b, 32b… that drive the work device 3b (for example, first hydraulic actuators for performing any of the following actions: swinging, boom raising and lowering, arm raising and lowering, or work tool swinging) and a control valve that controls the supply and discharge of hydraulic fluid to the first hydraulic actuators 30b, 31b, 32b…. Furthermore, the operating section 22 for operating the first hydraulic actuators 30b, 31b, 32b… corresponding to the oil passages connecting the branched oil passage L15 may be shared with the operating section 22 for operating the connecting hydraulic actuator 80, or they may be separate.

[0041] (1-4. Summary) (Item 1) A work machine 1 having an attachment mounting portion 36b to which a connecting attachment 8 can be attached, which includes a connecting hydraulic actuator 80 that can be switched between a connected state in which a work attachment 9 is connected and a disconnected state in which the work attachment 9 is disconnected, the work machine 1 having an attachment mounting portion 36b to which a connecting attachment 8 can be attached, the control valve 60D that controls the supply and discharge of hydraulic fluid, a first oil passage L6 that connects the control valve 60D and a first hydraulic actuator 30a, a branch oil passage L15 that branches off from the first oil passage L6 and can be connected to the connecting hydraulic actuator 80, and the branch oil passage L in the first oil passage L6 The work machine 1 includes an on-off valve 63 provided on the side of the first hydraulic actuator 30a more than the branching point with 15 and for opening and closing the first oil passage L6, and a connecting control valve 64 for opening and closing the branch oil passage L15, and is switchable between a first state in which the on-off valve 63 is in an open state and the connecting control valve 64 is in a closed state, supplying hydraulic fluid from the control valve 60D to the first hydraulic actuator 30a, and a second state in which the on-off valve 63 is in a closed state and the connecting control valve 64 is in an open state, supplying hydraulic fluid from the control valve 60D to the connecting hydraulic actuator 80.

[0042] According to the work machine 1 of item 1, in the first state, hydraulic fluid is supplied to the first hydraulic actuator 30a, so the first hydraulic actuator 30a can be operated. In contrast, in the second state, the hydraulic fluid that was supplied to the first hydraulic actuator 30a is not supplied to the first hydraulic actuator 30a, but is instead supplied to the connecting hydraulic actuator 80. This allows the connecting attachment 8 to be switched between a connected state and a disconnected state while the first hydraulic actuator 30a is stopped. Therefore, according to the work machine 1 of item 1, the number of parts and costs can be reduced, and safety can be improved.

[0043] (Item 2) The connecting hydraulic actuator 80 is configured to release the connection of the work attachment 9 when hydraulic fluid is supplied from the control valve 60D, and to maintain the connection of the work attachment 9 when hydraulic fluid is not supplied from the control valve 60D, as described in item 1 of the work machine 1.

[0044] According to the work equipment 1 in item 2, the supply of hydraulic fluid from the control valve 60D is only required when the connection is released, and the connection of the work attachment 9 does not need to rely on hydraulic fluid. As a result, even if a hydraulic fluid leak occurs, the work attachment 9 can be maintained in the connected state without being affected by the hydraulic fluid supply condition.

[0045] (Item 3) The work machine 1 according to item 1, comprising a coupling operation switch 25 for switching between the first state and the second state, and a control device 5 that controls the operation of the on-off valve 63 and the coupling control valve 64 in response to the operation of the coupling operation switch 25.

[0046] According to the work machine 1 in item 3, the connection operation switch 25 is operated according to the operator's intention, switching between the first state and the second state prevents accidental switching between the connected state and the disconnected state, thus ensuring safety.

[0047] (Item 4) The work machine 1 according to item 3, wherein the on-off valve 63 and the connecting control valve 64 are operated in response to an operation on the connecting operation switch 25 when the operating state of the first hydraulic actuator 30a or the equipment driven by the first hydraulic actuator 30a is in a predetermined state, while the on-off valve 63 and the connecting control valve 64 are not operated even if the connecting operation switch 25 is operated when the operating state is not the predetermined state.

[0048] According to the work machine 1 of item 4, the coupling control valve 64 will not operate (will not switch to the first or second state) unless a predetermined state is reached, thus preventing unintentional coupling or becoming coupled.

[0049] (Item 5) The work machine 1 according to item 1, comprising an operating unit 22 for operating the control valve 60D to change the flow rate of hydraulic fluid supplied from the control valve 60D, wherein in the first state the operating unit 22 operates the first hydraulic actuator 30a, and in the second state the operating unit 22 operates the connecting hydraulic actuator 80.

[0050] According to the work machine 1 of item 5, in both the first and second states, the first hydraulic actuator 30a or the connecting control valve 64 can be activated by operating the operating unit. In other words, operations corresponding to either the first or second state can be performed with the common operating unit 22 without providing a separate, independent operating unit.

[0051] (Item 6) The work machine 1 according to item 1, comprising a machine body 2, a lifting arm 31a attached to the machine body 2, a dozer blade 32a attached to the tip of the lifting arm 31a, and a lifting hydraulic actuator 30a for raising and lowering the lifting arm 31a, wherein the first hydraulic actuator 30a is the lifting hydraulic actuator 30a.

[0052] According to the work machine 1 of item 6, in the first state, hydraulic fluid is supplied to the lifting hydraulic actuator 30a that raises and lowers the lifting arm 31a, so that the lifting arm 31a can be raised and lowered. In the second state, with the operation of raising and lowering the lifting arm 31a prohibited, the connecting attachment 8 can be switched between a connected state and a disconnected state.

[0053] (Item 7) The work machine 1 according to item 1, having a hydraulic fluid outlet port 61 capable of supplying hydraulic fluid to an external hydraulic device equipped with the first hydraulic actuator 90, wherein the first oil passage L6 is an oil passage connecting the control valve 60D and the hydraulic fluid outlet port 61.

[0054] According to the work machine 1 of item 7, in the first state, hydraulic fluid is supplied to the external equipment via the hydraulic fluid outlet port 61, so that the external equipment can be operated, and in the second state, with the operation (operation) of the external equipment prohibited, the connecting attachment 8 can be switched between a connected state and a disconnected state.

[0055] (Item 8) The work machine 1 according to item 1, comprising a machine body 2, a work device 3b having a boom 34b rotatably attached to the machine body 2, and an arm 35b rotatably attached to the boom 34b, wherein the first hydraulic actuator is a hydraulic actuator 30b, 31b, 32b that drives at least a part of the work device 3b.

[0056] According to the work device 1 of item 1, in the first state, hydraulic fluid is supplied to the hydraulic actuators 30b, 31b, and 32b that drive at least a part of the work device 3b, so that the work device 3b can be operated. In the second state, with the operation (movement) of the work device 3b prohibited, the connecting attachment 8 can be switched between a connected state and a disconnected state.

[0057] (Item 9) The work machine 1 according to item 1 comprises a machine body 2, a working device 3b having a boom 34b rotatably attached to the machine body 2, and an arm 35b rotatably attached to the boom 34b, wherein the attachment mounting portion 36b is provided on the arm 35b.

[0058] According to the work machine 1 of item 9, since the arm 35b is provided with an attachment mounting portion 36b, the connecting attachment 8 is attached to the tip of the arm 35b. This allows the position of the connecting attachment 8 to be changed by rotating at least one of the boom 34b and the arm 35b, and facilitates the operation of connecting the work attachment 9 to the connecting attachment 8. [Explanation of Symbols]

[0059] 1: Work machine 2: Aircraft 3a: Work equipment (dozer equipment) 3b: Working equipment (excavator equipment) 5: Control device 8: Connecting attachment 9: Work attachments 22:Operation unit 25: Linking operation switch 30a: Lifting hydraulic actuator (First hydraulic actuator: Lifting cylinder) 30b: Hydraulic actuator (First hydraulic actuator: Boom cylinder) 31b: Hydraulic actuator (First hydraulic actuator: Arm cylinder) 32b: Hydraulic actuator (First hydraulic actuator: Tool cylinder) 32a: Dozer blade 34b: Boom 35b: Arm 36b: Attachment mounting section 60D: Control valve (Lifting cylinder control valve) 61: Hydraulic fluid outlet port (AUX port) 63: Shut-off valve 64: Control valve for connection 80: Hydraulic actuator for linking 90: First hydraulic actuator (hydraulic actuator) L15: Branch oil channel L6: 1st oilway

Claims

1. A work machine having an attachment mounting section to which a connecting attachment can be attached, including a connecting hydraulic actuator that can be switched between a connected state in which a work attachment is connected and a disconnected state in which the connection of the work attachment is released, A control valve that controls the supply and discharge of hydraulic fluid, A first oil passage connecting the control valve and the first hydraulic actuator, A branch oil passage that branches off from the first oil passage and can be connected to the connecting hydraulic actuator, An on-off valve is provided on the side of the first hydraulic actuator that is closer to the branch point of the first oil passage with the branch oil passage, and which opens and closes the first oil passage. Includes a connecting control valve that opens and closes the branched oil passage, A work machine that can switch between a first state in which the on-off valve is in the open position and the connecting control valve is in the closed position, supplying hydraulic fluid from the control valve to the first hydraulic actuator, and a second state in which the on-off valve is in the closed position and the connecting control valve is in the open position, supplying hydraulic fluid from the control valve to the connecting hydraulic actuator.

2. The work machine according to claim 1, wherein the connecting hydraulic actuator can release the connection of the work attachment when hydraulic fluid is supplied from the control valve, and maintains the connection of the work attachment when hydraulic fluid is not supplied from the control valve.

3. A coupling operation switch for switching between the first state and the second state, The work machine according to claim 1, further comprising a control device that controls the operation of the on-off valve and the connecting control valve in response to an operation on the connecting operation switch.

4. The work machine according to claim 3, wherein the on-off valve and the connecting control valve are operated in response to an operation on the connecting operation switch when the operating state of the first hydraulic actuator or the equipment driven by the first hydraulic actuator is in a predetermined state, while the on-off valve and the connecting control valve are not operated even if the connecting operation switch is operated when the operating state is not the predetermined state.

5. The control valve is operated by an operating unit that changes the flow rate of the hydraulic fluid supplied from the control valve, The work machine according to claim 1, wherein in the first state, the first hydraulic actuator is operated by the operating unit, and in the second state, the connecting hydraulic actuator is operated by the operating unit.

6. The aircraft and, The dozer device comprises a lifting arm attached to the machine body, a dozer blade attached to the tip of the lifting arm, and a lifting hydraulic actuator for raising and lowering the lifting arm. The work machine according to claim 1, wherein the first hydraulic actuator is the lifting hydraulic actuator.

7. The work machine according to claim 1, having a hydraulic fluid outlet port capable of supplying hydraulic fluid to an external hydraulic device equipped with the first hydraulic actuator, wherein the first oil passage is an oil passage connecting the control valve and the hydraulic fluid outlet port.

8. The aircraft and, The machine comprises a working device having a boom rotatably attached to the machine body and an arm rotatably attached to the boom, The work machine according to claim 1, wherein the first hydraulic actuator is a hydraulic actuator that drives at least a part of the work device.

9. The aircraft and, The machine comprises a working device having a boom rotatably attached to the machine body and an arm rotatably attached to the boom, The work machine according to claim 1, wherein the attachment mounting portion is provided on the arm.

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