JP4449780B2 - Piping connection method and connection structure for work machines - Google Patents

Description

  The present invention relates to a pipe connection method and a connection structure for connecting a hydraulic pipe during assembly in a working machine such as a crusher or a dismantling machine.

  The background art will be described by taking as an example a dismantling machine with an ultra-long attachment used for dismantling high-rise buildings.

  As shown in FIG. 12, the dismantling machine includes a front portion of a base machine A that includes a crawler-type lower traveling body 1 and an upper revolving body 2 that is mounted on the lower traveling body 1 so as to be rotatable about a vertical axis. And a work attachment B having a long boom 3 is mounted.

  The boom 3 of this work attachment B has the first, second, third, and fourth stage boom bodies 4, 5, 6, and 7 in order from the bottom in relation to each other around the horizontal axis. The lower end of the first stage boom body 4 is attached to the upper swing body 2 of the base machine A.

  In addition, the first boom cylinder 8 for raising and lowering the boom body 4 (the entire boom) between the upper swing body 2 and the first stage boom body 4, the distal end portion of the first stage boom body 4 and the second stage boom body. A second boom cylinder 9 for raising and lowering the second stage boom body 5 between the second boom body 5 and a third boom for raising and lowering the third stage boom body 6 between the second stage boom body 5 and the third stage boom body 6. Between the cylinder 10 and the third-stage boom body 6 and the fourth-stage boom body 7, a fourth boom cylinder 11 for raising and lowering the fourth-stage boom body 7 is provided.

  The boom cylinders 8 to 11 are provided on the lower surface side of the boom, and the boom 3 as a whole is raised and lowered by the boom cylinders 8 to 11, and the joint portions of the booms are jointed as shown by chain lines or broken lines in FIG. 12. As a bending and stretching operation.

  An opening / closing type crushing device 12 as a working device is provided at the tip of the boom 3 (tip of the fourth-stage boom body 7), and the crushing device 12 crushes the concrete lump and the like to dismantle the building. Is called.

  In FIG. 12, reference numeral 13 denotes a crushing device cylinder that rotates the crushing device 12 up and down around a horizontal axis. Further, the crushing device 12 is configured to be rotatable so that its direction is variable, and is rotated by a hydraulic motor 14 (see FIG. 16).

  In such a long boom 3, each stage boom body 4, 6, 7 other than the second stage boom body 5 exceeds the length and weight restrictions during transportation as a single block, so that a plurality of booms Disassembled into sections (attachment pieces), transported, and assembled on site.

  For example, the first stage boom body 4 is disassembled into four first (basic), second, third, and fourth boom sections 4a to 4d, and these are pin-connected at opposite ends when assembled.

  In this dismantling machine, the hydraulic actuators (the boom cylinders 8 to 11, the crushing cylinder 13, and the hydraulic motor 14) that operate the work attachment B are connected to the hydraulic pump and tank mounted on the upper swing body 2 of the base machine A. The hydraulic piping is divided into boom sections and provided as unit piping that is connected to adjacent ones. When the boom 3 is assembled, adjacent boom sections are connected to each other, and the unit pipings are also connected to each other. Connected.

  FIGS. 13 and 14 show the state of connection and piping connection of the first to third boom sections 4a, 4b, 4c of the first stage boom body 4 as an example.

  Here, only five of the numerous hydraulic pipes are illustrated, and unit pipes 15, 16, 17, 18, 19 are provided on the side surfaces of the first to third boom sections 4a, 4b, 4c. Yes.

  Specifically, 15 and 16 are unit pipes for the second boom cylinder 9 in FIG. 12, 17 and 18 are two unit pipes for the hydraulic motor 14 for rotating the crushing device 12, and 19 is the same. This is a unit pipe for draining the motor 14.

  Assembly is performed in order from the boom base end side. That is, after the first boom section 4a is attached to the upper swing body 2, the second boom section 4b is arranged at the tip of the first boom section 4a, and the third boom section 4c is arranged at the tip of the second boom section 4b. Connected with

  After the boom sections are connected to each other, the unit pipes 15 to 19 are connected to each other by a joint male side joint and a female side joint) 20 and 21.

  15 and 16 schematically show this connection state as a hydraulic circuit. In both figures, reference numerals 22 and 23 denote control valves for controlling the operation of the second boom cylinder 9 and the hydraulic motor 14, and unit pipes 15 to 18 for the second boom cylinder and the hydraulic motor are control valves 22 and 23, respectively. The drain pipe 19 is directly connected to the tank without passing through the control valve.

  In addition, there is no prior patent document regarding the connection technology of hydraulic piping in such work machines.

  In an assembly / disassembly type work machine such as this dismantling machine, the joints 20 and 21 connecting the unit pipes can be attached / detached with one touch, and there is almost no oil leakage at the time of attachment / detachment. A hermetic joint (referred to as a quick coupler or a self-sealing coupling) having the above is used.

  However, this type of joint has a built-in poppet type or spool type valve, and the valve opens by the coupling operation force.Therefore, pressure remains in the pipe with the unit pipe disconnected, and this remains when connected. The pressure (residual pressure) becomes a resistance, making it difficult to connect the joints.

  In particular, this phenomenon becomes prominent when the temperature of trapped oil (residual oil) rises due to an increase in the outside air temperature and the residual pressure increases, or in the case of a large joint.

  As a countermeasure against this point, it is conceivable to provide a well-known pressure relief valve at the joint portion that releases the residual pressure in the pipe to the outside by simply pressing a button.

  However, in this case, there is a new problem that if the extracted residual oil is discharged to the outside as it is, the machine and the site are contaminated.

  Here, the problem can be solved by placing an oil container on the ground or near the pressure relief valve, and collecting the residual oil in this oil container, but the container is moved every time the assembly progresses or the container becomes full. Since there are many troubles, such as having to replace | exchange, assembly efficiency becomes worse. There is also a problem in that it is difficult to process the oil collected in the container.

  Such a problem is serious in the case of a large attachment having many connection points for unit piping as described above, but is common to work machines that divide and connect hydraulic piping into unit piping.

  Therefore, the present invention uses a method in which the residual pressure in the pipe is released by a pressure release valve, and there is no risk of soiling the machine or the site by the residual oil that has been removed, and this residual pressure release operation including the treatment of the recovered oil is performed. It is an object of the present invention to provide a work machine pipe connection method and a connection structure that can be easily and efficiently performed.

  According to the first aspect of the present invention (pipe connection method), the hydraulic pipes connecting the hydraulic source and the tank and the hydraulic actuator mounted on the base machine are divided into a plurality of unit pipes, and the unit pipes are connected to each other by joints. In the pipe connection method of the working machine to be connected, each unit pipe is provided with a pressure relief valve, and the pressure relief pipe is provided in a state directly connected to the tank, and the pressure relief valve and the pressure relief pipe are connected to the pressure relief hose. And connecting the joints of the unit pipes to each other after the residual pressure in the unit pipe is drawn from the pressure release valve to the tank via the pressure release hose and the pressure release pipe.

  The invention of claim 2 (piping connection method) is provided with a work attachment that is assembled and disassembled by a plurality of attachment pieces in the base machine, and this work attachment is provided with a hydraulic actuator that operates the attachment. Hydraulic piping connecting the hydraulic source and tank mounted on the base machine and the hydraulic actuator is provided as a unit piping that is divided for each attachment piece and is connected to adjacent ones of the work attachments. At the time of assembling, the attachment pieces are connected in order from the base end side, and in the pipe connection method of the work machine in which the unit pipes of the two attachment pieces to be connected are connected by mutual joints, the pressure release pipe is connected to the base end side. Directly connected to the tank and attached Provided with the tip side extended in accordance with the assembly, each unit pipe is provided with a pressure release valve that releases the residual pressure in the unit pipe, and one end of the pressure release hose is the target to be released when the attachment pieces are connected Connect the other end to the pressure relief valve of the piping, and connect the other end of the unit piping to the tank via the pressure relief hose and the pressure relief pipe. To connect.

  According to a third aspect of the present invention, in the method of the second aspect, the pressure release pipe is divided for each attachment piece and provided so that adjacent ones can be connected to each other, and when the attachment pieces are connected, the pressure release hose is provided. One end of the pipe is connected to the pressure relief valve of the unit pipe on the front end side, and the other end is connected to the pressure release pipe on the base end side. The tank is withdrawn through a pressure release pipe.

  According to a fourth aspect of the present invention, in the method of the second or third aspect, the drain pipe for returning the drain oil of the hydraulic equipment provided in the work attachment to the tank is divided for each attachment piece, and adjacent ones can be connected. When connecting the attachment pieces together, connect one end of the pressure release hose to the pressure release valve of the distal unit piping, and connect the other end to the drain piping of the proximal attachment piece. It is also used as a tube.

  According to a fifth aspect of the present invention, in the method of the fourth aspect, the work attachment includes a boom, and a unit pipe and a divided drain pipe are provided for each boom section as an attachment piece constituting the boom.

  In the invention of claim 6 (pipe connection structure), the hydraulic source and the hydraulic pipe connecting the tank and the hydraulic actuator mounted on the base machine are divided into a plurality of unit pipes. In the pipe connection structure of the work machine to be connected, the pressure relief valve provided in each unit pipe, the pressure relief pipe directly connected to the tank, the pressure relief valve and the pressure relief pipe are connected to each other. A pressure relief hose is provided for extracting residual pressure in the piping to a tank via a pressure relief valve and a pressure relief pipe.

  In the invention of claim 7 (piping connection structure), the base machine is provided with a work attachment that is assembled and disassembled by a plurality of attachment pieces, and the work attachment is provided with a hydraulic actuator that operates the attachment. Hydraulic piping connecting the hydraulic source and tank mounted on the base machine and the hydraulic actuator is provided as a unit piping that is divided for each attachment piece and is connected to adjacent ones of the work attachments. At the time of assembly, the attachment pieces are connected together in order from the base end side, and the unit pipes of the two attachment pieces to be connected are connected to each other by a joint. The drain valve and the base end are directly connected to the tank. And a pressure relief hose having a distal end extended in accordance with the assembly of the attachment, and a pressure relief hose. One end of the pressure relief hose is a pressure relief valve of the distal unit piping, and the other end is a pressure on the proximal side. It is configured so that it can be connected to the extraction tube.

  The invention of claim 8 is the structure of claim 6 or 7, wherein an adapter provided with a pressure relief valve is provided in a joint of each unit pipe, and a protective means for protecting the pressure relief valve is provided on this adapter. .

  According to a ninth aspect of the present invention, in the configuration of the eighth aspect, as a protective means, a protective wall is provided that projects from the outer periphery of the adapter in the radial direction of the unit pipe to protect the pressure relief valve.

  In a tenth aspect of the present invention, in the configuration of the ninth aspect, a pair of protective walls are provided in a state where the pressure relief valve is sandwiched from both sides.

  According to an eleventh aspect of the present invention, in the configuration of the eighth aspect, a protrusion that protrudes in the radial direction of the unit pipe is provided on the outer peripheral side of the adapter, and a pressure relief port is opened in the axial direction of the unit pipe in the protrusion. The pressure relief valve is attached in the axial direction of the unit pipe in a state of communicating with the pressure relief port.

  According to the pipe connection method and connection structure of the present invention, the residual pressure (residual oil) in the unit pipe is extracted from the pressure release valve to the tank via the pressure release pipe, so there is no risk of contaminating the machine or the site with the extracted oil. .

  In this case, according to the inventions of claims 2 to 5 and claim 7, in the work machine that connects the plurality of attachment pieces in order from the base end side and connects the unit pipes, the pressure release pipe is connected to the tip side as the assembly proceeds. Since the residual pressure in the unit pipe is drawn into the tank via the pressure relief valve and this pressure relief pipe, the working machine with an ultra-long attachment can be used.

  In some cases, the residual pressure also accumulates in the unit pipe on the most proximal side. However, according to the inventions of claims 1, 2, 6, and 7, a pressure relief valve is provided on the unit pipe on the most proximal side. As a result, the residual pressure can be extracted to the tank via the pressure release valve and pressure release pipe in the same manner as other unit pipes.

  Moreover, according to the present invention, it is only necessary to connect the pressure release valve and the pressure release pipe with a pressure release hose. Therefore, compared with the method of removing residual oil from a container placed on the ground or near the pressure release valve, Work can be done much more efficiently.

  In this case, according to the inventions of claims 2 to 5 and claim 7, in the working machine for assembling a work attachment (particularly a large work attachment) by connecting a plurality of attachment pieces, the container is moved as the assembly proceeds. This eliminates the hassle of having to replace the tank every time the tank is full, so that the assembly work efficiency of the work attachment can be improved.

  Further, since the residual oil is collected in a tank mounted on the machine, it is not necessary to treat the oil that has been extracted as in the case of extracting it into a container.

  Further, according to the inventions of claims 4 and 5, since the drain pipe for hydraulic equipment that is originally provided is used as the pressure release pipe as it is, it is not necessary to add a dedicated pressure release pipe and the cost can be reduced. .

  By the way, since the pressure release valve is provided so as to protrude in the radial direction from the pipe, the pressure release valve may be damaged and oil may flow out particularly in a working machine in which crushed pieces fall down like a dismantling machine.

  In this respect, according to the eighth to eleventh aspects of the present invention, since the protective means for protecting the pressure relief valve is provided in the adapter, it is possible to prevent the pressure relief valve from being damaged and the oil to flow out.

  In this case, in the inventions of claims 9 to 10, as a protection means, a protective wall (a pair of protective walls sandwiching the pressure relief valve between them) is provided on the adapter itself provided with the pressure relief valve. In No. 11, since the adapter is provided with a projecting portion projecting in the radial direction and the pressure relief valve is attached to the adapter in the pipe axis direction, the protective structure is simple and the cost can be reduced.

  An embodiment of the present invention will be described with reference to FIGS.

Basic embodiment (see FIGS. 1 to 8)
In the following embodiments, the same parts as those in the conventional technology shown in FIGS.

  In the following embodiment, among the boom sections 4a to 4d as attachment pieces constituting the first stage boom body 4 in the dismantling machine shown in FIG. 12, the first and second boom sections 4a and 4b are connected. Take this as an example.

  In the following configuration and method, the second and third boom sections 4b and 4c and the third and fourth boom sections 4c and 4d are connected to each other, and the boom sections of the third stage boom body 6 are connected to each other. This also applies to the connecting portions of the first stage boom body 4 and the second stage boom body 5, the second stage boom body 5 and the third stage boom body 6, and the third stage boom body 6 and the fourth stage boom body 7. Can be applied to.

  1 to 4 show the connection between the boom sections 4a and 4b and the connection status of the unit pipes provided on them.

  Here, according to the description of the background art, the case of a total of five cylinders, two for the motor, and one for the motor drain is illustrated, and the drain unit pipe 19 is arranged on the uppermost side, In the following order, cylinder unit pipes 15 and 16 and motor unit pipes 17 and 18 are arranged.

  FIG. 1 is before connection (pipe connection), FIG. 2 is during pressure release of one cylinder unit pipe 15, and FIG. 3 is connecting both boom sections 4a and 4b and connecting the cylinder unit pipes 15 and 15 to each other. FIG. 4 shows a state where all the unit pipes 15 to 19 are connected.

  The unit pipes 15 to 19 are provided with sealed joints (for example, called quick couplers) 20 and 21 that can be attached and detached with a single touch. They are connected to each other.

  A pressure relief valve 24 is provided in each of the joints (female side joints) 21 on the base end side of the unit pipes 15 to 18 excluding the drain unit pipe 19.

  The structure of the joint 21 with this pressure relief valve 24 is shown in FIGS.

  An adapter 27 is attached by a half-shaped flange 26 between the female joint 21 on the base end side and the pipe base 25, and a pressure relief valve 24 is connected to the adapter 27 in the pipe radial direction and at the tip of the valve. Is provided in a state protruding from the outer peripheral side of the adapter.

  As shown in FIG. 7, the pressure relief valve 24 includes a spring-biased poppet 24a. When the poppet 24a is pushed upward from the outside of the figure, the pressure relief port 24b opens to perform a pressure relief action.

  In addition, you may use the pressure relief valve of other structures, such as what opens a pressure relief port by pushing a button part.

  One end side of the pressure relief hose 28 is detachably connected to the pressure relief valve 24 by a union screw 28a. At this time, the poppet 24a of the pressure relief valve 24 is pushed by the push rod 28b on the hose side. 24 opens.

  A joint 29 having the same structure and size as the female joint 21 (without the pressure relief valve 24) is provided on the other end side of the pressure relief hose 28.

  On the other hand, since the pressure relief valve 24 is provided so as to protrude from the outer periphery of the adapter as described above, there is a possibility that the pressure relief valve 24 may be damaged by a fragmented piece or the like falling during the dismantling operation.

  Therefore, as a protective means for protecting the pressure relief valve 24 from the crushed pieces or the like to prevent this damage, a pair of protective walls 30, 30 face each other so that the pressure relief valve 24 is sandwiched from both sides on the outer periphery of the adapter 27. Is provided.

  A procedure for connecting pipes when assembling the boom 3 shown in FIG. 12 will be described.

  After the first boom section 4a is attached to the upper swing body 2 of the base machine A, the second boom section 4b is disposed on the distal end side of the first boom section 4a as shown in FIG.

  Thereafter, as shown in FIG. 2, one end side of the pressure relief hose 28 is connected to the pressure relief valve 24 of the cylinder unit pipe 15 on the distal end side (second boom section 4b side), and the other end side of the same hose 28 is connected to the pressure relief valve 24. The drain unit pipe 19 on the base end side (the first boom section 4a side) is connected by mutual joints 29 and 20.

  As a result, the distal-end cylinder unit pipe 15 and the proximal-end drain unit pipe 19 are connected via the pressure relief valve 24. If the pressure relief operation is performed in this state, the distal-end cylinder unit pipe is automatically connected. Fifteen residual pressure (residual oil) passes through the proximal-side drain unit pipe 19 and is collected in a tank mounted on the upper swing body 2.

  Here, as shown in FIG. 3, the unit pipes 15, 15 for both the front end side and the base end side cylinders are connected to each other by the joints 20, 21.

  At this time, the inside of the distal-end cylinder unit pipe 15 is compressed by the coupling operation of the joints 20 and 21, which causes an increase in the residual pressure, but the inside of the pipe 15 remains in communication with the proximal-side drain unit pipe 19. Therefore, the residual pressure escapes to the base end drain unit pipe 19 as it is.

  Thereafter, this operation is performed in the same manner for the other unit pipes 16 to 18, and finally, the pressure release hose 28 is removed from the pressure release valve 24 and the base end side drain unit pipe 19, and the drain unit pipes 19, 19 are connected to each other. This completes the connection (see FIG. 4).

  The connection between the second boom section 4b and the third boom section 4c, the connection between the third boom section 4c and the fourth boom section (not shown here), the connection between the boom elements and the connection between the unit pipes are the same as described above. It can be carried out.

  Thus, the residual pressure (residual oil) in the unit pipe is drawn from the pressure release valve 24 to the tank via the drain unit pipe 19 provided in each boom section or each stage boom body. There is no risk of soiling the site.

  In this case, the drain pipe (drain unit pipe 19) is extended to the tip side as the boom is assembled, and the residual pressure in the unit pipe is drawn into the tank via the pressure relief valve 24 and the extended drain pipe. Therefore, it is possible to deal with the exemplified work machine with a super long attachment.

  In addition, since it is only necessary to connect the other end of the pressure relief hose 28 connected to the pressure relief valve 24 to the drain-side unit pipe 19 on the base end side, a method of draining residual oil from a container placed on the ground or near the pressure relief valve. Compared to the above, there is no trouble of moving the container or replacing the container when it is full as the assembly proceeds, and the work efficiency of pipe connection (machine assembly) is improved.

  Further, since the residual oil is collected in a tank mounted on the machine, it is not necessary to treat the oil that has been extracted as in the case of extracting it into a container.

  In this case, since the motor drain pipe originally provided on the boom 3 is used as it is as a pressure release pipe, it is not necessary to add a dedicated pressure release pipe, and the cost can be reduced.

  In addition, since the adapter 27 is provided with a pair of protective walls 30, 30 that protect the pressure relief valve 24, the shredded pieces that fall down are guarded by the protective walls 30, 30 and the pressure relief valve 24 is Outflow).

  In the initial stage of assembly, the pressure confined in the most proximal unit pipes 15 to 18 is theoretically released to the tank by operating the control valves 22 and 23 shown in FIG. 16, but the cause is unknown. However, even if it does in this way, it may not be released and it may be stored as residual pressure.

  Therefore, although not shown, a pressure relief valve 24 is also provided at the distal end side joint 20 of the unit pipes 15 to 18 on the most proximal side, and the pressure relief valve 24 and the pressure relief pipe 19 are decompressed like the other unit pipes. The residual pressure may be released by connecting with the hose 28.

Other embodiments
(1) As a protection means, instead of the pair of protection walls 30, 30, as shown in FIG. 9, a cylindrical protection wall 31 may be provided on the outer periphery of the adapter 27 so as to surround the pressure relief valve 24. .

  Further, as shown in FIGS. 10 and 11, a part of the outer periphery of the adapter 27 is protruded in the radial direction to provide a protrusion 32, and a pressure release port 33 is provided in the protrusion 32 in the pipe axis direction. A pressure relief valve 24 may be provided at the port 33. A cap 34 is attached to the tip when the pressure relief valve 24 is not used. It is desirable to provide this cap 34 also on the pressure relief valve 24 in the basic embodiment.

  As another protective means, a protective cover may be attached to the adapter 27 so as to cover the pressure relief valve when not in use and to be opened when the pipe is connected.

  (2) In the above embodiment, the motor drain pipe for the crushing device is used as the pressure relief pipe. However, the drain pipe of the counter balance valve for the hydraulic cylinder, for example, the hydraulic cylinder is also used as the pressure relief pipe. You may take the structure to do.

  Further, in the above embodiment, the drain pipe that is originally provided is used as a pressure relief pipe. However, when there is no drain pipe or when it is difficult to use the drain pipe as a pressure relief pipe. A dedicated pressure release pipe may be provided.

  (3) Further, the present invention is not limited to a dismantling machine, but a work loader such as a scrap loader that transports waste or the like can be assembled and disassembled by a plurality of attachment pieces, and a hydraulic pipe is provided on the work attachment. Can be widely applied to work machines.

  In addition, the present invention is not limited to work attachments, and can be applied to a part that has a configuration in which a hydraulic pipe is divided into a plurality of unit pipes and these are connected by joints in a work machine.

It is a side view which shows the state before piping connection by basic embodiment of this invention. It is a side view which shows the state which has extracted the residual pressure about some piping. It is a side view which shows the state which connected the same piping. It is a side view which shows the state which completed the connection of all piping. It is an enlarged side view of a pipe connection part. It is the VI-VI line expanded sectional view of FIG. It is a partially cutaway enlarged view of a joint adapter and a pressure relief hose connection part. It is a disassembled perspective view of a pipe connection part. It is a disassembled perspective view of the adapter and pressure relief valve concerning other embodiment of this invention. It is a partially cutaway side view of the piping connection part concerning another embodiment of this invention. It is a disassembled perspective view of the adapter and pressure release valve concerning the embodiment. It is a side view of a demolition machine to which the present invention is applied. It is a side view which shows the state at the time of the boom assembly start of a demolition machine. It is a side view which shows the same assembly progress state. It is a figure which shows typically the piping connection condition at the time of an assembly as a hydraulic circuit. It is a figure which shows the same connection completion state.

Explanation of symbols

DESCRIPTION OF SYMBOLS A Base machine 1 Lower traveling body 2 Upper turning body 3 Boom 4-6 Each stage boom body which comprises a boom 4a, 4b, 4c, 4d Boom section as an attachment piece which comprises a 1st stage boom body 8-11 Hydraulic actuator Boom cylinder 13 Cylinder for the crushing device 14 Hydraulic motor 12 Crushing device 15-18 Unit piping 19 Drain unit piping (pressure release tube)
20,21 Joint 24 Pressure release valve 27 Adapter 28 Pressure release hose 29 Pressure release hose joint 30, 30 Protection wall as protection means 32 Projection as protection means 33 Pressure release port provided at the projection in the pipe axis direction

Claims (11)

  In the pipe connection method of the working machine in which the hydraulic pipe connecting the hydraulic source and the tank and the hydraulic actuator mounted on the base machine is divided into a plurality of unit pipes, and the unit pipes are connected to each other by a joint. Each unit pipe is provided with a pressure relief valve and a pressure relief pipe is directly connected to the tank. The pressure relief valve and the pressure relief pipe are connected by a pressure relief hose to reduce the residual pressure in the unit pipe. A pipe connection method for a work machine, wherein the joints of unit pipes are connected to each other after being pulled out from the release valve via a pressure release hose and a pressure release pipe.   The base machine is provided with a work attachment that is assembled and disassembled by a plurality of attachment pieces. The work attachment is provided with a hydraulic actuator that operates the attachment, and a hydraulic source and a tank mounted on the base machine. Hydraulic piping connecting the hydraulic actuator is provided as unit piping that is divided for each attachment piece and connected to adjacent ones, and when attaching the work attachment, the attachment pieces are connected in order from the base end side. In the pipe connection method of the work machine in which the unit pipes of the two attachment pieces to be connected are connected to each other by a joint, the pressure release pipe is connected directly to the tank on the base end side and the tip side is connected to the tank according to the assembly of the attachment. Extended On the other hand, each unit pipe is provided with a pressure release valve that releases the residual pressure in the unit pipe, and when the attachment pieces are connected to each other, one end of the pressure release hose is used as a pressure release valve for the unit pipe to be released. The other end is connected to the pressure release pipe, and after the residual pressure of the unit pipe is drawn from the pressure release valve to the tank via the pressure release hose and the pressure release pipe, the joints of the unit pipes are connected to each other. Piping connection method for work machines.   3. The work machine pipe connection method according to claim 2, wherein the pressure release pipe is divided for each attachment piece and is provided in a state in which adjacent ones can be connected to each other. Connect one end to the pressure relief valve of the unit pipe on the distal end side and the other end to the pressure relief pipe on the proximal end side, and remove the residual pressure in the distal side unit pipe from the pressure relief valve to the pressure relief hose and the pressure on the proximal end side. A pipe connection method for a work machine, wherein the tank is pulled through a drain pipe.   4. The work machine pipe connection method according to claim 2, wherein the drain pipe for returning the drain oil of the hydraulic equipment provided in the work attachment to the tank is divided for each attachment piece and adjacent ones can be connected to each other. When connecting attachment pieces, the drain pipe is depressurized by connecting one end of the pressure release hose to the pressure release valve of the unit pipe on the distal end side and the other end to the drain pipe on the base side attachment piece. A pipe connection method for a work machine, which is also used as a pipe.   5. The work machine pipe connection method according to claim 4, wherein the work attachment includes a boom, and a unit pipe and a divided drain pipe are provided for each boom section as an attachment piece constituting the boom. Machine piping connection method.   In the pipe connection structure of the working machine in which the hydraulic pipes connecting the hydraulic source and the tank and the hydraulic actuator mounted on the base machine are divided into a plurality of unit pipes, and the unit pipes are connected to each other by a joint. The pressure relief valve provided in each unit pipe, the pressure relief pipe directly connected to the tank, the pressure relief valve and the pressure relief pipe are connected to reduce the residual pressure in the unit pipe. A piping connection structure for a working machine, comprising: a pressure releasing hose that is pulled into a tank through a pipe.   The base machine is provided with a work attachment that is assembled and disassembled by a plurality of attachment pieces. The work attachment is provided with a hydraulic actuator that operates the attachment, and a hydraulic source and a tank mounted on the base machine. Hydraulic piping connecting the hydraulic actuator is provided as a unit piping that is divided for each attachment piece and connected to adjacent ones, and when attaching the work attachment, the attachment pieces are connected in order from the base end side. The pressure relief valve provided in each unit pipe and the base end side are directly connected to the tank in the pipe connection structure of the working machine in which the unit pipes of both attachment pieces to be connected are connected to each other by joints. And for assembly of attachments The pressure release hose has a pressure release hose with a distal end extended and a pressure release hose. One end of the pressure release hose is a pressure release valve of the front end unit piping, and the other end is a pressure release pipe on the proximal end side. A piping connection structure for a work machine, characterized in that the connection is possible.   The pipe connection structure for a work machine according to claim 6 or 7, wherein an adapter having a pressure relief valve is provided in a joint of each unit pipe, and a protective means for protecting the pressure relief valve is provided on the adapter. Piping connection structure for working machines.   9. The work machine pipe connection structure according to claim 8, wherein a protective wall is provided as a protection means to project the radial direction of the unit pipe from the outer periphery of the adapter to protect the pressure relief valve. Construction.   10. The work machine pipe connection structure according to claim 9, wherein a pair of protective walls are provided in a state where the pressure release valve is sandwiched from both sides.   9. The work machine pipe connection structure according to claim 8, wherein a projecting portion projecting in a radial direction of the unit pipe is provided on an outer peripheral side of the adapter, and a pressure release port is opened in the projecting portion in an axial direction of the unit pipe. A pipe connection structure for a work machine, characterized in that a pressure relief valve is installed in the axial direction of the unit pipe in a state of communicating with the pressure relief port.

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