Work machine

Abstract

To provide a work machine capable of efficiently mounting an attachment by a quick coupler without requiring an operator to operate a switch.SOLUTION: A hydraulic excavator 1 comprises a work implement 30 having a boom 31 and an arm 32 that serve as arm members and a bucket 33 that serves as an attachment, a quick coupler 50 that detachably connects the bucket 33 and the arm 32 by extending and retracting a lock cylinder 53, a switching valve 71 that switches the flow of hydraulic oil guided to the lock cylinder 53, a pressure boost valve 72 that boosts the pressure of hydraulic oil discharged from a hydraulic pump 28, and a controller 80 that controls both the switching valve 71 and the pressure boost valve 72. When the controller 80 determines that the quick coupler 50 and pins 61, 62 are in contact with each other, the controller 80 controls the pressure boost valve 72 to boost the pressure, and switches the switching valve 71 so that the hydraulic oil is guided to the bottom chamber of the lock cylinder 53.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a work machine to which an attachment can be attached using a quick coupler. [Background technology]

[0002] Work machines such as hydraulic excavators can perform a variety of tasks by replacing their standard bucket with buckets of different shapes or a wide variety of attachments. Quick couplers are commonly known as components for attaching various attachments to arm members. These quick couplers are equipped with a lock cylinder that provides a locking mechanism for the attachment, and are attached to the tip of the arm member. The attachment is provided with an adapter that connects to the quick coupler, and the quick coupler's lock cylinder extends and engages with the adapter, thereby holding the attachment in place.

[0003] For example, Patent Document 1 discloses a method for controlling the lock cylinder of a quick coupler in which a controller starts the supply of hydraulic oil from a hydraulic pump to the lock cylinder of the quick coupler based on a switch operation by an operator, and stops the supply of hydraulic oil to the lock cylinder based on the pressure in the oil passage between the hydraulic pump and the lock cylinder. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-147756 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the control method described in Patent Document 1 requires the operator to operate a switch to supply hydraulic oil to the lock cylinder of the quick coupler. In this case, the operator must temporarily remove his or her hand from the control lever used to operate the work equipment when operating the switch. When the operator removes his or her hand from the control lever, various problems arise, such as the operation of the control lever malfunctioning, causing the work equipment to behave in an unintended manner by the operator, or temporarily halting work, making it difficult to return to work efficiently. While it is possible to place the switch on the control lever, this does not sufficiently prevent erroneous operation of the switch or erroneous operation of the control lever while operating the switch.

[0006] An object of the present invention is to provide a work machine that allows an attachment to be efficiently attached using a quick coupler without the need for an operator to operate a switch. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a working device having a machine body, an arm member rotatably attached to the machine body, and an attachment rotatably attached to the tip side of the arm member, a quick coupler attached to the tip end of the arm member and including a locking hydraulic cylinder that detachably connects the attachment and the arm member by extending and retracting a rod, an operating device for operating the working device, a hydraulic pump that supplies hydraulic oil to the locking hydraulic cylinder, a hydraulic oil tank that stores the hydraulic oil, and a switching valve that is provided between the hydraulic pump and the locking hydraulic cylinder and that switches so as to direct the hydraulic oil discharged from the hydraulic pump to a bottom chamber or a rod chamber of the locking hydraulic cylinder. a boost valve provided between the hydraulic pump and the switching valve for controlling whether or not to boost the pressure of the hydraulic oil discharged from the hydraulic pump; and a controller for controlling the switching valve and the boost valve, respectively. The working machine further comprises a contact state detection device for detecting a contact state of the quick coupler with a pin attached to the attachment, and the controller determines the contact state between the quick coupler and the pin based on a detection value detected by the contact state detection device, and when it is determined that the quick coupler and the pin are in contact, controls the boost valve to boost the pressure and switches the switching valve to guide the hydraulic oil to the bottom chamber of the locking hydraulic cylinder. [Effects of the Invention]

[0008] According to the present invention, an attachment can be efficiently attached using a quick coupler without the need for an operator to operate a switch. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiment. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an external side view showing an example of the configuration of a hydraulic excavator according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is an external side view showing an example of a configuration of a quick coupler. [Figure 3] FIG. 3 is an external bottom view of the quick coupler shown in FIG. 2. [Figure 4] FIG. 2 is a diagram showing an example of a configuration of a quick coupler hydraulic circuit related to driving the quick coupler. [Figure 5] FIG. 2 is a functional block diagram showing functions of a controller. [Figure 6] FIG. 10 is a diagram illustrating a first connection state between the quick coupler and the bucket. [Figure 7] FIG. 10 is a diagram illustrating a second connection state between the quick coupler and the bucket. [Figure 8] FIG. 10 is a diagram illustrating a third connection state between the quick coupler and the bucket. [Figure 9] 10 is a flowchart showing the flow of processing executed by a controller. [Figure 10] 10 is a flowchart showing the flow of processing executed by a controller according to Modification 1 of the present invention. [Figure 11] 10 is a flowchart showing the flow of processing executed by a controller according to Modification 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a crawler hydraulic excavator will be described as one aspect of a work machine according to an embodiment of the present invention.

[0011] <Overall configuration of hydraulic excavator 1> First, the overall configuration of a hydraulic excavator 1 will be described with reference to FIG.

[0012] FIG. 1 is an external side view showing an example of the configuration of a hydraulic excavator 1 according to an embodiment of the present invention.

[0013] The hydraulic excavator 1 comprises a self-propelled crawler-type running body 10, a rotating body 20 that is rotatably provided above the running body 10, and a working device 30 that is attached to the front of the rotating body 20 and performs work such as excavation and leveling.

[0014] The running body 10 has a pair of crawlers 11 on the left and right that extend in the front-to-rear direction of the body, and the pair of crawlers 11 are rotated in contact with the ground by the driving force of a pair of travel motors (not shown), causing the body to move. The pair of travel motors are mounted on the left and right of the running body 10 corresponding to the left and right crawlers 11, respectively, and are driven independently of each other to rotate the left and right crawlers 11 forward and reverse independently. Note that only the left crawler 11 of the pair of left and right crawlers 11 is shown in FIG. 1.

[0015] The revolving body 20 comprises a revolving frame 21 serving as a base, a cab 22 in which the operator sits, a counterweight 23 that maintains balance with the working device 30 to prevent the hydraulic excavator 1 from tipping over, and a machine room 24 that houses the equipment necessary to drive the hydraulic excavator 1.

[0016] On the revolving frame 21, an operator's cab 22 is placed on the front left side, a counterweight 23 is placed on the rear end, and a machinery room 24 is placed between the operator's cab 22 and the counterweight 23.

[0017] The operator's cab 22 is provided with an operator's seat 25 where the operator sits, a monitor 26 disposed in front of the operator's seat 25 as a display device that displays the operating status of the hydraulic excavator 1, and an operating device 27 for operating the work equipment 30. In Fig. 1, the operator's seat 25, the monitor 26, and the operating device 27 are each indicated by dashed lines.

[0018] The machinery room 24 is provided with a swing motor (not shown), a hydraulic pump 28 that supplies hydraulic oil to each of the actuators that drive the swing motor and the working device 30, and a hydraulic oil tank 29 that stores hydraulic oil. In Fig. 1, the hydraulic pump 28 and the hydraulic oil tank 29 are each indicated by dashed lines.

[0019] The working device 30 comprises a boom 31 whose base end is rotatably attached to the swivel frame 21, a boom cylinder 31A that drives the boom 31, an arm 32 that is rotatably attached to the tip of the boom 31, an arm cylinder 32A that drives the arm 32, a bucket 33 that is rotatably attached to the tip side of the arm 32, and a bucket cylinder 33A that drives the bucket 33.

[0020] In the working device 30, the arm member is composed of the boom 31 and the arm 32, but this is not limited to this, and the arm member may be composed of a single member or may be composed of a combination of two or more members.

[0021] Furthermore, in the work device 30, a quick coupler 50 is rotatably attached to the tip of the arm 32, and the bucket 33 is attached to the arm 32 via the quick coupler 50. The quick coupler 50 detachably connects the bucket 33 and the arm 32 by the extension and retraction of a rod of a lock cylinder 53 (see FIG. 2), which will be described later.

[0022] The boom cylinder 31A connects the revolving frame 21 and the boom 31, and rotates (elevates) the boom 31 in the vertical direction relative to the revolving body 20 by extension and contraction of the rod.

[0023] The arm cylinder 32A connects the boom 31 and the arm 32, and rotates the arm 32 in the front-rear direction relative to the boom 31 as the rod extends and retracts.

[0024] The bucket cylinder 33A connects the arm 32 and the quick coupler 50, and rotates the quick coupler 50 and the bucket 33 in the front-rear direction relative to the arm 32 as the rod extends and contracts.

[0025] The bucket 33 is used to scoop up loads such as earth and sand and lower them into a predetermined location. In this embodiment, the bucket 33 is described as an example of an attachment (working tool) attached to the tip of the arm member (boom 31 and arm 32), but the attachment is not limited to this and may be something other than the bucket 33, such as a grapple for grabbing lumber, rocks, waste, etc., or a breaker for excavating rock. This allows the hydraulic excavator 1 to perform a variety of tasks, including excavation and crushing, using an attachment suited to the type of work.

[0026] An adapter 60 is attached to the bucket 33, which serves as a connection portion with the quick coupler 50. The adapter 60 has a rear pin 61 and a front pin 62, and the quick coupler 50 holds this pair of pins 61, 62, thereby connecting the bucket 33 to the quick coupler 50. Note that the pins attached to the attachment do not necessarily have to be a pair, and there is no particular limit to the number of pins as long as the quick coupler 50 can hold them.

[0027] The work device 30 is also provided with a boom attitude sensor 34 that detects the attitude of the boom 31, an arm attitude sensor 35 that detects the attitude of the arm 32, and a bucket attitude sensor 36 that detects the attitude of the bucket 33.

[0028] The boom position sensor 34 is disposed at the connection portion between the revolving frame 21 and the boom 31 and detects, for example, the angle that the boom 31 forms with respect to the revolving frame 21. The arm position sensor 35 is disposed at the connection portion between the boom 31 and the arm 32 and detects, for example, the angle that the arm 32 forms with respect to the boom 31. The bucket position sensor 36 is disposed at the connection portion between the arm 32 and the quick coupler 50 and detects, for example, the angle that the quick coupler 50 and bucket 33 form with respect to the arm 32.

[0029] Therefore, the boom attitude sensor 34, the arm attitude sensor 35, and the bucket attitude sensor 36 are each an aspect of an attitude detection device that detects the attitude of the work implement 30.

[0030] <Quick Coupler 50 Configuration> Next, the configuration of the quick coupler 50 will be described with reference to FIGS.

[0031] Fig. 2 is an external side view of the quick coupler 50. Fig. 3 is an external bottom view of the quick coupler 50. Fig. 4 is a diagram showing an example of the configuration of a quick coupler hydraulic circuit 70 related to driving the quick coupler 50.

[0032] The quick coupler 50 has a lock cylinder 53 as a locking hydraulic cylinder whose rod extends and retracts when hydraulic oil is supplied, a rear pin connected portion 55 as a connected portion to which a rear pin 61 (see Figures 6 to 8), which is one of the pins in the bucket 33, is connected, and a front pin connected portion 56 as a connected portion to which a front pin 62 (see Figures 6 to 8), which is the other pin in the bucket 33, is connected.

[0033] Rear pin connected portion 55 is provided with a first sensor 51 that detects the contact state of rear pin connected portion 55 with rear pin 61. Similarly, front pin connected portion 56 is provided with a second sensor 52 that detects the contact state of front pin connected portion 56 with front pin 62.

[0034] That is, the first sensor 51 and the second sensor 52 are each a form of a contact state detection device that detects the contact state of the quick coupler 50 with the pins (rear pin 61 and front pin 62) attached to the bucket (attachment) 33. For example, a magnetic proximity sensor or a capacitance sensor is used for each of the first sensor 51 and the second sensor 52 as the contact state detection device.

[0035] Further, the lock cylinder 53 is provided with a third sensor 54 as an extension / contraction state detection device that detects the extension / contraction state of the rod.

[0036] With the rear pin 61 connected to the rear pin connecting portion 55 and the front pin 62 connected to the front pin connecting portion 56, the bucket 33 is held by the quick coupler 50 by the lock cylinder 53 extending and fixing the front pin 62 to the front pin connecting portion 56.

[0037] The lock cylinder 53 is driven by a quick coupler hydraulic circuit 70 shown in Figure 4. The quick coupler hydraulic circuit 70 is configured to include a hydraulic pump 28 that supplies hydraulic oil to the lock cylinder 53, a hydraulic oil tank 29 that stores the hydraulic oil, a switching valve 71 provided between the hydraulic pump 28 and the lock cylinder 53, and a pressure boost valve 72 provided between the hydraulic pump 28 and the switching valve 71.

[0038] The switching valve 71 is an electromagnetic switching valve controlled by the controller 80, and has a first switching position 71A where the hydraulic oil discharged from the hydraulic pump 28 is guided to the bottom chamber of the lock cylinder 53, and a second switching position 71B where the hydraulic oil discharged from the hydraulic pump 28 is guided to the rod chamber of the lock cylinder 53. In other words, the switching valve 71 switches so as to guide the hydraulic oil discharged from the hydraulic pump 28 to either the bottom chamber or the rod chamber of the lock cylinder 53.

[0039] The pressure boost valve 72 is an electromagnetic valve controlled by the controller 80, and has a third switching position 72A at which the pressure of the hydraulic oil discharged from the hydraulic pump 28 is increased, and a fourth switching position 72B at which the hydraulic oil discharged from the hydraulic pump 28 is directly discharged into the hydraulic oil tank 29. In other words, the pressure boost valve 72 controls whether or not the pressure of the hydraulic oil discharged from the hydraulic pump 28 is increased.

[0040] The rod of the lock cylinder 53 extends when the switching valve 71 switches to the first switching position 71A and the pressure boost valve 72 switches to the third switching position 72A. On the other hand, the rod of the lock cylinder 53 contracts when the switching valve 71 switches to the second switching position 71B and the pressure boost valve 72 switches to the third switching position 72A.

[0041] <Configuration of controller 80> Next, the configuration of the controller 80 will be described with reference to FIGS.

[0042] Fig. 5 is a functional block diagram showing the functions of the controller 80. Fig. 6 is a diagram showing a first connection state between the quick coupler 50 and the bucket 33. Fig. 7 is a diagram showing a second connection state between the quick coupler 50 and the bucket 33. Fig. 8 is a diagram showing a third connection state between the quick coupler 50 and the bucket 33.

[0043] In the controller 80, a CPU, RAM, ROM, input I / F, and output I / F are connected to one another via a bus. Various operating devices such as the operating device 27 and various sensors such as the first sensor 51, the second sensor 52, and the third sensor 54 are connected to the input I / F, and the switching valve 71, the pressure boost valve 72, and the like are connected to the output I / F.

[0044] In such a hardware configuration, the CPU reads out a control program (software) stored on a recording medium such as a ROM or an optical disk, expands it on RAM, and executes the expanded control program, whereby the control program and the hardware work together to realize the functions of the controller 80.

[0045] In this embodiment, the controller 80 is described as a computer configured by a combination of software and hardware, but this is not limited to this. For example, as an example of the configuration of another computer, an integrated circuit that realizes the functions of a control program executed on the hydraulic excavator 1 side may be used.

[0046] As shown in FIG. 5, the controller 80 includes a signal acquisition unit 81, a signal determination unit 82, and a signal output unit 83.

[0047] The signal acquisition unit 81 acquires a first sensor value Sr detected by the first sensor 51, a second sensor value Sf detected by the second sensor 52, and a third sensor value Sl detected by the third sensor 54.

[0048] The signal determination unit 82 determines the connection state between the quick coupler 50 and the bucket 33 (specifically, the contact state between the quick coupler 50 and the pins 61, 62) based on the first sensor value Sr, the second sensor value Sf, and the third sensor value Sl acquired by the signal acquisition unit 81.

[0049] In the following, the expressions "connected" and "connected state" are used, but this "connection" is sufficient if at least the pins 61, 62 are in contact with the quick coupler 50. Therefore, in the following, the "unconnected state" refers to a state in which the pins 61, 62 are not in contact with the quick coupler 50.

[0050] Here, the first sensor value Sr is Sr1 (Sr=Sr1) when the rear pin 61 is in a connected state where it is connected to the rear pin connected portion 55, and is Sr0 (Sr=Sr0) when the rear pin 61 is in an unconnected state where it is not connected to the rear pin connected portion 55.

[0051] The second sensor value Sf is Sf1 (Sf=Sf1) when the front pin 62 is in a connected state where it is connected to the front pin connecting portion 56, and is Sf0 (Sf=Sf0) when the front pin 62 is in an unconnected state where it is not connected to the front pin connecting portion 56.

[0052] The third sensor value Sl is Sl1 (Sl=Sl1) when the rod of the lock cylinder 53 is in an extended state, and is Sl0 (Sl=Sl0) when the rod of the lock cylinder 53 is not extended, i.e., in a contracted state.

[0053] If the first sensor value Sr acquired by the signal acquisition unit 81 is Sr0 (Sr=Sr0), the second sensor value Sf is Sf0 (Sf=Sf0), and the third sensor value Sl is Sl0 (Sl=Sl0), the signal determination unit 82 determines that the bucket 33 is in the zeroth connection state in which it is separated from the quick coupler 50.

[0054] Furthermore, if the first sensor value Sr acquired by the signal acquisition unit 81 is Sr1 (Sr=Sr1), the second sensor value Sf is Sf0 (Sf=Sf0), and the third sensor value Sl is Sl0 (Sl=Sl0), the signal determination unit 82 determines that the rear pin 61 is connected to the rear pin connection portion 55 and the connection of the bucket 33 to the quick coupler 50 has started, which is the first connection state (the state shown in FIG. 6).

[0055] Furthermore, when the first sensor value Sr acquired by the signal acquisition unit 81 is Sr1 (Sr=Sr1), the second sensor value Sf is Sf1 (Sf=Sf1), and the third sensor value Sl is Sl0 (Sl=Sl0), the signal determination unit 82 further determines that the front pin 62 is connected to the front pin connection portion 56 and is in a second connection state (the state shown in FIG. 7) in which the front pin 62 can be fixed by extending the rod of the lock cylinder 53.

[0056] In this second connected state, the front pin 62 is not fixed to the front pin connected portion 56 (unfixed state), and there is a possibility that the bucket 33 may fall off from the quick coupler 50, so the connection state between the quick coupler 50 and the bucket 33 is an "unconnected state."

[0057] Then, when the first sensor value Sr acquired by the signal acquisition unit 81 is Sr1 (Sr=Sr1), the second sensor value Sf is Sf1 (Sf=Sf1), and the third sensor value Sl is Sl1 (Sl=Sl1), the signal determination unit 82 determines that the rod of the lock cylinder 53 is fully extended (extended state) and the third connected state (state shown in FIG. 8) is established in which the front pin 62 is fixed to the front pin connected portion 56. In this third connected state, the bucket 33 does not fall off the quick coupler 50, and therefore the connection state between the quick coupler 50 and the bucket 33 is the "connected state."

[0058] When the signal determination unit 82 determines that the lock cylinder 53 and the bucket 33 are in the second connected state (disconnected state), the signal output unit 83 outputs a first switch command signal to the switching valve 71 to switch it to the first switch position 71A and a third switch command signal to the pressure boost valve 72 to switch it to the third switch position 72A in order to extend the rod of the lock cylinder 53. As a result, the front pin 62 is fixed to the front pin connected portion 56 (third connected state).

[0059] Furthermore, when the signal determination unit 82 determines that the lock cylinder 53 and the bucket 33 are in the third connected state, the front pin 62 is fixed to the front pin connected portion 56, and there is no need to extend the rod of the lock cylinder 53 any further, i.e., the hydraulic pump 28 does not need to supply any more hydraulic oil to the bottom chamber of the lock cylinder 53, and therefore the signal output unit 83 outputs a fourth switching command signal to the boost valve 72 to switch to the fourth switching position 72B.

[0060] <Processing within the controller 80> Next, a specific flow of processing executed within the controller 80 will be described with reference to FIG.

[0061] FIG. 9 is a flowchart showing the flow of processing executed by the controller 80.

[0062] In the controller 80, first, the signal acquisition unit 81 acquires the first sensor value Sr output from the first sensor 51, the second sensor value Sf output from the second sensor 52, and the third sensor value Sl output from the third sensor 54 (step S801).

[0063] Next, the signal determination unit 82 determines whether the quick coupler 50 and the bucket 33 are in the zeroth connection state based on the first sensor value Sr, the second sensor value Sf, and the third sensor value Sl acquired in step S801 (step S802).

[0064] In step S802, if it is determined that the quick coupler 50 and the bucket 33 are in the zeroth connection state (step S802 / YES), the signal acquisition unit 81 reacquires the first sensor value Sr output from the first sensor 51, the second sensor value Sf output from the second sensor 52, and the third sensor value Sl output from the third sensor 54 (step S803).

[0065] In addition, if it is determined in step S802 that the quick coupler 50 and the bucket 33 are not in the 0th connection state (step S802 / NO), the processing in the controller 80 ends.

[0066] Next, the signal determination unit 82 determines whether the quick coupler 50 and the bucket 33 are in the first connection state based on the first sensor value Sr, the second sensor value Sf, and the third sensor value Sl reacquired in step S803 (step S804).

[0067] In step S804, if it is determined that the quick coupler 50 and the bucket 33 are in the first connection state (step S804 / YES), the signal acquisition unit 81 reacquires the first sensor value Sr output from the first sensor 51, the second sensor value Sf output from the second sensor 52, and the third sensor value Sl output from the third sensor 54 (step S805).

[0068] If it is determined in step S804 that the quick coupler 50 and the bucket 33 are not in the first connected state (step S804 / NO), the process does not proceed to the next step S805 until the quick coupler 50 and the bucket 33 are in the first connected state.

[0069] Next, the signal determination unit 82 determines whether the quick coupler 50 and the bucket 33 are in the second connection state based on the first sensor value Sr, the second sensor value Sf, and the third sensor value Sl reacquired in step S805 (step S806).

[0070] In step S806, if it is determined that the quick coupler 50 and the bucket 33 are in the second connection state (step S806 / YES), the signal output unit 83 outputs a first switching command signal to the switching valve 71 (step S807), and then outputs a third switching command signal to the boost valve 72 (step S808).

[0071] Next, the signal acquisition unit 81 reacquires the first sensor value Sr output from the first sensor 51, the second sensor value Sf output from the second sensor 52, and the third sensor value Sl output from the third sensor 54 (step S809).

[0072] If it is determined in step S806 that the quick coupler 50 and the bucket 33 are not in the second connected state (step S806 / NO), the process does not proceed to the next step S807 until the quick coupler 50 and the bucket 33 are in the second connected state.

[0073] Next, the signal determination unit 82 determines whether the quick coupler 50 and the bucket 33 are in the third connection state based on the first sensor value Sr, the second sensor value Sf, and the third sensor value Sl reacquired in step S809 (step S810).

[0074] In step S810, if it is determined that the quick coupler 50 and the bucket 33 are in the third connection state (step S810 / YES), the signal output unit 83 outputs a fourth switching command signal to the boost valve 72 (step S811), and processing in the controller 80 ends.

[0075] If it is determined in step S810 that the quick coupler 50 and the bucket 33 are not in the third connected state (step S810 / NO), the process does not proceed to the next step S811 until the quick coupler 50 and the bucket 33 are in the third connected state.

[0076] The transition from the 0th connection state to the 2nd connection state can also be executed by the operator operating the operation device 27.

[0077] In this way, when the controller 80 determines that the bucket 33 is in a state where it can be connected to the quick coupler 50 based on the detection values ​​detected by the first sensor 51 and the second sensor 52, it outputs a switching command signal to each of the switching valve 71 and the pressure boost valve 72 to connect the quick coupler 50 and the bucket 33, thereby eliminating the need for an operator to operate a switch and enabling the quick coupler 50 and the bucket 33 to be connected efficiently.

[0078] <Variation 1> Next, a first modified example of the present invention will be described with reference to FIG.

[0079] Fig. 10 is a flowchart showing the flow of processing executed by the controller 80 according to the first modification of the present invention. In Fig. 10, components that are the same as those described in the embodiment are given the same reference numerals, and their description will be omitted. The same applies to the second modification below.

[0080] In the controller 80 according to this variant example 1, two processes are added between the process of step S806 and the process of step S807 executed within the controller 80 according to the embodiment, and one process is added after the process of step S811.

[0081] If it is determined in step S806 that the quick coupler 50 and the bucket 33 are in the second connection state (step S806 / YES), the controller 80 determines whether the signal acquisition unit 81 has acquired an operation signal from the operation device 27, i.e., whether operation is being performed by the operation device 27 (step S821).

[0082] More specifically, the controller 80 determines whether the input value X from the operation device 27 is equal to or less than a predetermined operation reference value X0. This "operation reference value X0" is a value set according to the input value that indicates a state in which no operation is being performed by the operation device 27.

[0083] If it is determined in step S821 that the input value X from the operating device 27 is equal to or less than the operation reference value X0 (X≦X0) (step S821 / YES), the controller 80 restricts the input of the operation signal from the operating device 27 so that the state in which the input value X of the operating device 27 is equal to or less than the operation reference value X0 (X≦X0) is maintained (step S822), and proceeds to step S807.

[0084] On the other hand, if it is determined in step S821 that the input value X from the operating device 27 is greater than the operation reference value X0 (X>X0) (step S821 / NO), the process does not proceed to step S822 until the input value X from the operating device 27 becomes equal to or less than the operation reference value X0.

[0085] Then, after the signal output unit 83 outputs the fourth switching command signal to the boost valve 72 in step S811, the controller 80 releases the input restriction on the operation signal from the operating device 27 (step S823) and terminates the overall processing related to the driving of the quick coupler 50.

[0086] In this way, by restricting the operation of the operating device 27 while the controller 80 is controlling the pressure boost valve 72 to increase the pressure, it is possible to reduce the risk that the front pin 62 will come off the front pin connected portion 56 before being fixed to the front pin connected portion 56, and that the lock cylinder 53 will fail to fix the front pin 62 to the front pin connected portion 56. In other words, it is possible to prevent a situation in which the lock cylinder 53 extends while the working device 30 is operating.

[0087] <Variation 2> Next, a second modification of the present invention will be described with reference to FIG.

[0088] FIG. 11 is a flowchart showing the flow of processing executed by the controller 80 according to the second modification of the present invention.

[0089] In the controller 80 according to the present modification 2, two processes are added before the process of step S809 executed in the controller 80 according to the embodiment, and these additional processes as well as the processes of steps S809 and S810 are performed in parallel with the processes of steps S806, S807, and S808. As in the modification 1, one process is added after the process of step S811.

[0090] When the signal acquisition unit 81 reacquires the first sensor value Sr, the second sensor value Sf, and the third sensor value Sl in step S805, the controller 80 determines whether the work implement 30 is in the reference position based on the position of the boom 31 acquired by the signal acquisition unit 81 (step S831).

[0091] More specifically, the controller 80 determines whether the attitude αb of the boom 31 detected by the boom attitude sensor 34 is equal to or greater than a predetermined attitude reference value αb0. This “attitude reference value αb0” is a value set according to the attitude (reference attitude) of the boom 31 within a range in which the bucket 33 does not fall off the quick coupler 50.

[0092] In step S831, the controller 80 does not necessarily have to determine whether or not the work implement 30 is in the reference posture based only on the posture of the boom 31 detected by the boom posture sensor 34; for example, the controller 80 may determine whether or not the work implement 30 is in the reference posture based on the posture of the arm 32 detected by the arm posture sensor 35 and the posture of the bucket 33 detected by the bucket posture sensor 36, in addition to the posture of the boom 31 detected by the boom posture sensor 34.

[0093] If it is determined in step S831 that the attitude αb of the boom 31 is equal to or greater than the attitude reference value αb0 (αb≧αb0), that is, if it is determined that the work implement 30 is in the reference attitude (step S831 / YES), the input of the operation signal from the operation device 27 is restricted so that the input value X of the operation device 27 is equal to or less than the operation reference value X0 (X≦X0) (step S832), and the process proceeds to step S809.

[0094] On the other hand, if it is determined in step S831 that the attitude αb of the boom 31 is smaller than the predetermined attitude reference value αb0 (αb<αb0), that is, if it is determined that the working implement 30 is not in the reference attitude (step S831 / NO), the processing of step S832 is skipped and the process proceeds to step S809.

[0095] In the present modified example 2, if it is determined in step S810 that the quick coupler 50 and the bucket 33 are not in the third connected state (step S810 / NO), the process returns to step S831 and is repeated.

[0096] Then, after the signal output unit 83 outputs the fourth switching command signal to the boost valve 72 in step S811, the controller 80 releases the input restriction on the operation signal from the operating device 27 (step S833) and terminates the overall processing related to the driving of the quick coupler 50.

[0097] In this way, when the working implement 30 is in the reference posture, the controller 80 restricts the operation by the operating device 27, thereby reducing the risk of the bucket 33 falling off the quick coupler 50 before the front pin 62 is fixed to the front pin connection portion 56 (a state in which the front pin 62 is not fixed to the front pin connection portion 56).

[0098] The above describes an embodiment of the present invention. However, the present invention is not limited to the above embodiment and includes various modifications. For example, the above embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to an embodiment including all of the described configurations. Furthermore, it is possible to replace part of the configuration of this embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of this embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of this embodiment with other configurations.

[0099] For example, in the above embodiment, a crawler-type hydraulic excavator 1 was used as an example of one type of work machine, but this is not limited to this, and the present invention can also be applied to other work machines, such as wheel loaders.

[0100] In the above embodiment, instead of the second sensor 52, posture sensors that detect the posture of the work implement 30 (boom posture sensor 34, arm posture sensor 35, and bucket posture sensor 36) may be used. [Explanation of symbols]

[0101] 1: Hydraulic excavator (work machine) 10: Running body (aircraft) 20: Rotating body (aircraft) 27: Operating device 28: Hydraulic pump 29: Hydraulic oil tank 30: Work equipment 31: Boom (arm component) 32: Arm (arm component) 33: Bucket (attachment) 34: Boom position sensor (position detection device) 35: Boom position sensor (position detection device) 36: Bucket attitude sensor (attitude detection device) 50: Quick coupler 51: First sensor (contact state detection device) 52: Second sensor (contact state detection device) 53: Lock cylinder (hydraulic cylinder for locking) 54: Third sensor (expansion / contraction state detection device) 55: Rear pin connected part (connected part) 56: Front pin connected part (connected part) 61: Rear pin (pin) 62: Front pin (pin) 71: Switching valve 72: Pressure boost valve 80: Controller

Claims

1. The aircraft and a working device having an arm member rotatably attached to the machine body and an attachment rotatably attached to a tip end of the arm member; a quick coupler attached to the tip of the arm member and including a locking hydraulic cylinder that detachably connects the attachment and the arm member by extending and retracting a rod; an operating device for operating the working device; a hydraulic pump for supplying hydraulic oil to the locking hydraulic cylinder; a hydraulic oil tank that stores the hydraulic oil; a switching valve that is provided between the hydraulic pump and the locking hydraulic cylinder and that switches so as to guide the hydraulic oil discharged from the hydraulic pump to a bottom chamber or a rod chamber of the locking hydraulic cylinder; a pressure boost valve that is provided between the hydraulic pump and the switching valve and controls whether or not to boost the pressure of the hydraulic oil discharged from the hydraulic pump; a controller that controls the switching valve and the pressure boost valve; In a work machine equipped with a contact state detection device that detects a contact state of the quick coupler with a pin attached to the attachment, The controller determining a contact state between the quick coupler and the pin based on a detection value detected by the contact state detection device; When it is determined that the quick coupler and the pin are in contact with each other, the pressure boost valve is controlled to increase pressure, and the switching valve is switched so that the hydraulic oil is introduced into the bottom chamber of the locking hydraulic cylinder. A work machine characterized by:

2. 2. The work machine according to claim 1, The locking hydraulic cylinder further includes an extension / contraction state detection device for detecting an extension / contraction state of the rod of the locking hydraulic cylinder, The controller determining whether the rod of the locking hydraulic cylinder is in an extended state based on the extension / contraction state of the rod detected by the extension / contraction state detection device; When it is determined that the rod of the locking hydraulic cylinder is in an extended state, the pressure boost valve is controlled not to increase pressure. A work machine characterized by:

3. 2. The work machine according to claim 1, The controller When it is determined that the quick coupler and the pin are in contact with each other, it is further determined whether the operating device is being operated based on an operation signal output from the operating device, When it is determined that the operating device is not being operated, the switching valve is switched so that the hydraulic oil is guided to the bottom chamber of the locking hydraulic cylinder. A work machine characterized by:

4. 4. The work machine according to claim 3, The controller While the boost valve is controlled to increase pressure, the input of the operation signal from the operating device is limited. A work machine characterized by:

5. 2. The work machine according to claim 1, The working device further includes a posture detection device for detecting the posture of the working device, The attachment includes: A pair of said pins are attached, The quick coupler includes: a pair of connected portions to which the pair of pins are connected are provided, The contact state detection device provided on each of the pair of connected portions of the quick coupler, The controller when it is determined that one of the connected portions of the quick coupler and one of the pins of the attachment are in contact based on the detection value detected by one of the contact state detection devices, it is determined whether the attitude of the working device detected by the attitude detection device is a reference attitude of the working device within a range in which the attachment will not come off the quick coupler; When it is determined that the posture of the working device detected by the posture detection device is the reference posture, input of an operation signal from the operating device is restricted. A work machine characterized by:

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