Work machine

Abstract

Provided is a work machine offering improved convenience. This work machine comprises a case part 70 inside which a pressure chamber 27 is defined by connection of a chamber cover 71 and a chamber base 72, a piston part (striking part) that strikes a fastener by moving to one side in a first direction AR1 due to the pressure of gas inside the pressure chamber 27, and a cap 73 via which the inside and outside of the pressure chamber 27 can communicate while the chamber cover 71 and the chamber base 72 are connected by an opening operation performed by an operator. The cap 73 restricts the chamber cover 71 and the chamber base 72 from being disconnected without the opening operation being performed.

Description

Working machine

[0001] The present invention relates to a working machine.

[0002] Conventionally, a nail driver, which is a working machine that moves a piston and a driver blade and strikes a stopper with the driver blade, is known. In the nail driver of Patent Document 1, the driver blade descends due to the pressure in a pressure accumulation chamber filled with gas and strikes the stopper. The pressure accumulation chamber is formed inside a main tank in which a cap and a holder are fixed by a screw member.

[0003] International Publication No. 2019 / 208102

[0004] The nail driver of Patent Document 1 is configured such that the main tank can be disassembled by removing the screw member. Therefore, there was a possibility that the main tank would be disassembled while the pressure in the pressure accumulation chamber was higher than the atmospheric pressure. In this case, since various members constituting the main tank are under the load due to the pressure in the pressure accumulation chamber, the parts are difficult to remove, and the workability may be impaired.

[0005] A working machine according to an embodiment includes a first member and a second member, a case portion that defines a pressure chamber inside when the first member and the second member are coupled, a striking portion that strikes a stopper by moving in one direction of the first direction due to the pressure of the gas inside the pressure chamber, and an opening portion that enables the inside and outside of the pressure chamber to communicate while the first member and the second member are coupled when an opening operation is performed by an operator. The opening portion restricts the release of the coupling between the first member and the second member without the opening operation being performed.

[0006] A working machine according to an embodiment includes a first member and a second member, a case portion that defines a pressure chamber inside when the first member and the second member are coupled, a striking portion that strikes a stopper by moving in one direction of the first direction due to the pressure of the gas inside the pressure chamber, and an opening portion that enables the inside and outside of the pressure chamber to communicate while the first member and the second member are coupled when an opening operation is performed by an operator. When the operator releases the coupling between the first member and the second member, the opening operation is performed.

[0007] According to the present invention, it is possible to provide a work machine with improved convenience.

[0008] This is an external side view of the implement of the embodiment. This is a side view illustrating the internal structure of the implement of the first embodiment. This is a plan view of the pressure accumulator in the implement of the first embodiment. This is a cross-sectional view of the pressure accumulator along line A-A in Figure 3. This is a cross-sectional view illustrating the disassembly procedure of the pressure accumulator of the pressure accumulator when the pressure chamber is filled with gas. This is a plan view of the pressure accumulator in the implement of the second embodiment. This is a cross-sectional view of the pressure accumulator along line B-B in Figure 10. This is a cross-sectional view illustrating the disassembly procedure of the pressure accumulator. This is a cross-sectional view of the pressure accumulator when the pressure chamber is filled with gas. This is a cross-sectional view of the pressure accumulator in a modified implement. This is a cross-sectional view of the implement of the third embodiment. This is an exploded perspective view of a part of the implement. This is a cross-sectional view of the implement along line C-C in Figure 15. This is a cross-sectional view of the implement along line D-D in Figure 15. This is a cross-sectional view of the implement along line E-E in Figure 15. This is a cross-sectional view of the implement along line F-F in Figure 19. This is a cross-sectional view of the implement along line G-G in Figure 19. This is a cross-sectional view of the fixing cover. This is an external perspective view illustrating the disassembly procedure for the pressure accumulator. This is an external perspective view illustrating the disassembly procedure for the pressure accumulator. This is an external perspective view illustrating the disassembly procedure for the pressure accumulator. This is an external perspective view illustrating the disassembly procedure for the pressure accumulator. This is a perspective view illustrating the removal of the striking part.

[0009] <First Embodiment> The working machine of the first embodiment will be described with reference to the drawings.

[0010] Figure 1 is an external side view of the work machine 10 according to the first embodiment. Figure 2 is a side view showing the internal structure of the work machine 10. The work machine 10 is, for example, an electric nail gun and has a housing 11, a piston part (striking part) 12, a nose part 13, a power supply unit 14, an electric motor 15, a gear case 16, a pressure accumulator 18, and a magazine 54.

[0011] <Housing 11> The housing 11 is the outer casing element of the work machine 10. The housing 11 has a cylinder case 20 that houses the piston section 12 (described later), a handle 21, a motor case 22 that houses the electric motor 15 (described later), a mounting section 23, and a top cover 24. The handle 21 and the motor case 22 are connected to the cylinder case 20. The mounting section 23 is connected to the handle 21 and the motor case 22.

[0012] <Cylinder Case 20> The cylinder 28 is supported in the cylinder case 20. The cylinder 28 is a cylindrical metal object. In the following description, the direction in which the cylinder 28 extends is referred to as the first direction AR1. The cylinder 28 is fixed to the nose portion 13, which will be described later, and is positioned relative to the cylinder case 20 via the nose portion 13 in the direction of the first axis AX1, which is parallel to the first direction AR1, and in the radial direction (a direction perpendicular to the first axis AX1). The first axis AX1 is the direction in which the piston portion 12, which will be described later, extends. The side of the cylinder 28 toward the nose portion 13 is referred to as downward, and the side of the cylinder 28 toward the pressure accumulation portion 18, which will be described later, is referred to as upward. For this reason, the first direction AR1 is sometimes referred to as the up-down direction. The direction that intersects (is perpendicular to) the first direction AR1 is referred to as the second direction AR2.

[0013] <Handle 21> The handle 21 extends along the second direction AR2 of the work machine 10. As shown in Figure 1, a trigger 211 is provided below the handle 21. The operator can operate the trigger 211 while gripping the handle 21. A trigger switch (not shown) is provided inside the handle 21, and outputs an operation signal (ON signal) when operating force is applied to the trigger 211. When the operating force on the trigger 211 is released, the trigger switch stops outputting the operation signal.

[0014] <Motor Case 22> The motor case 22 is a housing that accommodates the electric motor 15 and the gear case 16, which will be described later. The motor case 22 has a cylindrical shape that extends along the rotation axis of the electric motor 15. The rotation axis of the electric motor 15 extends in the first direction (up and down direction) AR1, that is, in the direction that intersects the first axis AX1.

[0015] <Mounting section 23> The mounting section 23 is located at the rear end of the handle 21 and the motor case 22. The power supply unit 14, which will be described later, is detachably attached to the mounting section 23. A control unit (not shown) is also provided inside the mounting section 23. The control unit is electrically connected to the trigger switch by wiring. When the trigger 211 is operated by the operator, the control unit outputs an electrical signal that instructs the start or stop of the operation of the electric motor 15, which will be described later, according to the operation.

[0016] In the following explanation, in the second direction AR2, the side of the cylinder case 20 relative to the handle 21 may be referred to as the front, and the side of the mounting portion 23 relative to the handle 21 may be referred to as the rear. For this reason, the second direction AR2 may be referred to as the front-rear direction.

[0017] <Top Cover 24> The top cover 24 is detachably attached to the top of the cylinder case 20. The top cover 24 attached to the cylinder case 20 is part of the housing 11 that constitutes the outer structure of the work machine 10. The space enclosed by the top cover 24 and the cylinder case 20 is where the pressure accumulation unit 18, which will be described later, is located.

[0018] <Piston section (striking section) 12> The piston section (striking section) 12 has a piston 50 and a driver blade 51. The piston 50 has a cylindrical shape with the first axis AX1 as its axis. The piston 50 is provided on one side (downward side) of the first direction AR1 with respect to the pressure accumulation section 18, which will be described in detail later, and is always biased to one side (downward side) of the first direction AR1 by the pressure of the pressure chamber 27 provided in the pressure accumulation section 18.

[0019] The piston 50 is movable in a first direction AR1 along the first axis AX1 inside the cylinder 28. A sealing member is attached to the outer circumferential surface of the piston 50. The sealing member contacts the inner circumferential surface of the cylinder 28 to form a sealing surface.

[0020] The driver blade 51 is made of metal, for example. The driver blade 51 is connected to the piston 50 on the lower side of the piston 50 in the first direction AR1 and extends along the first axis AX1. As described above, since the piston 50 is movable in the first direction AR1, the driver blade 51 is also movable in the first direction AR1.

[0021] Multiple racks (not shown) are arranged in the center of the driver blade 51. The driver blade 51 moves upward in the first direction AR1 by the driving force from an electric motor 15 (described later) via a transmission mechanism 17 that engages with the racks. When the driver blade 51 moves downward in the first direction AR1 (direction of the first axis AX1) in Figure 1, it is called descending. When the driver blade 51 moves upward in the first direction AR1 (direction of the first axis AX1) in Figure 1, it is called ascending.

[0022] <Nose section 13> The nose section 13 is positioned and arranged relative to the cylinder case 20 in the direction of the first axis AX1 and in the radial direction of the cylinder 28. The nose section 13 has a bumper support section 31, a bumper 35, a blade guide 37, and a push lever 39. The bumper support section 31 is cylindrical and has a guide hole 34. The guide hole 34 is positioned centered on the first axis AX1.

[0023] A bumper 35 is positioned within the bumper support portion 31. The bumper 35 is integrally formed from synthetic rubber, such as elastomer. The bumper 35 is provided with a guide hole 36 centered on the first axis AX1. The aforementioned driver blade 51 is movable in the first direction AR1 along the first axis AX1 within the guide hole 36.

[0024] Furthermore, a blade guide 37 is provided on the bumper support portion 31. The blade guide 37 protrudes downward from the bumper support portion 31 in the first direction AR1. Inside the blade guide 37, a concentric injection passage 38 is formed centered on the first axis AX1. Within this injection passage 38, the driver blade 51 is movable in the first direction AR1 along the first axis AX1. A fastener N, such as a nail, housed in a magazine 54 (described later), is supplied to this injection passage 38.

[0025] The push lever 39 is located below the injection passage 38 and contacts the workpiece during operation of the work machine 10. The push lever 39 is mounted to be movable along the first direction AR1 in response to a pushing operation that presses it against the workpiece.

[0026] <Power supply unit 14> As shown in Figure 1, the power supply unit 14 is a DC power supply that is detachably attached to the mounting unit 23 and supplies power to the electric motor 15, etc. The power supply unit 14 has a housing case and a plurality of battery cells housed in the housing case. The battery cells are rechargeable and dischargeable secondary batteries, and any of lithium-ion batteries, nickel-metal hydride batteries, lithium-ion polymer batteries, or nickel-cadmium batteries can be used.

[0027] <Electric Motor 15> The electric motor 15 is a drive unit that rotates by receiving power from the power supply unit 14 and drives the piston unit 12. The electric motor 15 is located inside the motor case 22. The electric motor 15 is, for example, a brushless motor having a rotor and a stator.

[0028] <Gear Case 16> The gear case 16 is located inside the motor case 22 on the front side of the electric motor 15. The gear case 16 is cylindrical and does not rotate relative to the nose portion 13. Inside the gear case 16 is a reduction mechanism having an input element, an output element, and multiple sets of planetary gear mechanisms. The input element of the reduction mechanism is connected to the rotating shaft of the electric motor 15, and the input element is rotatably supported by a bearing. The rotational force of the output element of the reduction mechanism inside the gear case 16 is converted by the transmission mechanism 17 into a moving force in the first direction AR1 along the first axis AX1 and transmitted to the driver blade 51.

[0029] <Magazine 54> As shown in Figure 1, the magazine 54 is positioned relative to the motor case 22 on one side (downward) of the first direction (vertical direction) AR1. The magazine 54 houses a plurality of connected fasteners N. The plurality of fasteners N are connected to each other by connecting elements such as adhesive or wire. The fasteners N housed in the magazine 54 are supplied into the injection passage 38 by a supply mechanism (not shown).

[0030] <Pressure Accumulator 18> Figure 3 is a plan view of the pressure accumulator 18 as seen from above. Figure 4 is a cross-sectional view along the line A-A in Figure 3. For explanatory purposes, Figure 4 also shows a cross-section of the top cover 24. The pressure accumulator 18 is located in the space defined by the cylinder case 20 and the top cover 24. The pressure accumulator 18 includes a case 70, a cap 73, a relief valve 74, a check valve 75, and a cover cap 76.

[0031] <Case section 70> The case section 70 is made of metal, for example, and has a chamber cover 71 and a chamber base 72. The chamber cover 71 and the chamber base 72 can be detachably connected to each other. In the following description, the chamber cover 71 may be referred to as the first member and the chamber base 72 as the second member.

[0032] The chamber base 72 is, for example, cylindrical and is located on top of the piston 50. The chamber cover 71 is, for example, bottomed cylindrical. The chamber cover 71 is detachably attached to the top of the chamber base 72 by fasteners 720, such as screws, with its bottom surface facing upward. In the following description, the bottom surface of the chamber cover 71 that faces upward will be referred to as the upper end surface 710.

[0033] As shown in Figure 3, the case portion 70 is provided with, for example, five fixing portions 721 along the outer circumferential direction. The fixing portions 721 protrude radially outward from the outer peripheral walls of the chamber cover 71 and the chamber base 72.

[0034] As shown in Figure 4, the fixing portion 721 has a first fixing hole 722 and a second fixing hole 723. The first fixing hole 722 is formed in the chamber cover 71 and penetrates the fixing portion 721 of the chamber cover 71 along the first direction AR1. The second fixing hole 723 is formed in the chamber base 72 and penetrates the fixing portion 721 of the chamber base 72 along the first direction AR1. A female thread is formed on the inner circumferential surface of the second fixing hole 723. Alternatively, a female thread may be formed on the inner circumferential surface of the first fixing hole 722, or on both the inner circumferential surfaces of the first fixing hole 722 and the inner circumferential surfaces of the second fixing hole 723.

[0035] The fastener 720 is inserted into the first fixing holes 722 and the second fixing holes 723 formed in each of the five fixing parts 721. The fastener 720 consists of a shaft portion 724 and a head portion 725. The shaft portion 724 extends along the third axis AX3 which is aligned with the first direction AR1. A male thread is formed on the outer circumferential surface of the shaft portion 724. The head portion 725 is provided on the upper part of the shaft portion 724. The head portion 725 has an insertion hole 726 into which a tool 90 (see Figure 7), which will be described later, is inserted.

[0036] The fastener 720 is inserted into the first fastening hole 722 and the second fastening hole 723, and the male thread formed on the shaft portion 724 is screwed into at least one of the chamber cover 71 and the chamber base 72. As a result, the fastener 720 is attached to the first member, the chamber cover 71, and the second member, the chamber base 72, thereby connecting the chamber cover 71 and the chamber base 72.

[0037] When the chamber cover 71 and the chamber base 72 are joined, the space defined by the chamber cover 71 and the chamber base 72 becomes the pressure chamber 27. That is, the case portion 70 defines the pressure chamber 27. The pressure chamber 27 is filled with gas. Any compressible gas is acceptable. In addition to air, inert gases such as nitrogen gas and noble gases can be used as the gas. As described above, the pressure in the pressure chamber 27 provided in the pressure accumulation portion 18 constantly biases the piston portion 12 to one side (downward) in the first direction AR1.

[0038] A first hole 711 and a second hole 712 are formed in the upper end surface 710 of the chamber cover 71. The first hole 711 extends radially from the first axis AX1 along the second axis AX2, which intersects (orthogonal or nearly orthogonal to) the first direction AR1. Specifically, the first hole 711 extends from the first axis AX1 in the direction in which one of the five fixing parts 721a (for example, the front fixing part 721) is formed.

[0039] The first hole 711 is a housing hole into which a relief valve 74, described later, is installed and accommodated. The front end of the first hole 711 is an opening 711a, and the rear end of the first hole 711 communicates with the second hole 712, described later. Since the first hole 711 is formed on the upper end surface 710, the first hole 711 is located above the fixing portion 721a.

[0040] A female thread is formed on the inner circumferential wall of the first hole 711 on the opening 711a side. In the first hole 711, an air release hole 711b is formed on the side of the first axis AX1 from the region where the female thread is formed. The air release hole 711b connects the pressure chamber 27 and the first hole 711. In other words, the first hole 711 connects the inside and outside of the pressure chamber 27.

[0041] Furthermore, a relief opening 711c is formed in the first hole 711 on the side of the first axis AX1 than the air release hole 711b. The relief opening 711c connects the first hole 711 to the outside. A cap 73, which will be described later, is detachably attached to the first hole 711 having the above shape.

[0042] The second hole 712 is a through-hole that penetrates the upper end surface 710 in the vertical direction along the first axis AX1. In other words, the second hole 712 connects the inside and outside of the pressure chamber 27. The second hole 712 is a housing hole that accommodates the check valve 75, which will be described later. The second hole 712 is also an insertion hole into which an air hose is inserted when gas is filled into the pressure chamber 27.

[0043] Below the second hole 712, a first region 712a and a second region 712b with different inner diameters are formed. The first region 712a is formed at the lower end of the second hole 712. The second region 712b is formed above the first region 712a. The diameter of the second region 712b is smaller than the diameter of the first region 712a.

[0044] <Cap 73> The cap 73 extends along the second axis AX2 and is detachably attached to the first hole 711 from the side of the opening 711a. The cap 73 is composed of a shaft portion 731, a head portion 732, and a flange portion 733. The head portion 732 is formed at the end of the shaft portion 731. An insertion hole 734 into which a tool 90 (see FIG. 6) used when attaching and detaching the cap 73 to and from the first hole 711 is inserted is formed in the head portion 732.

[0045] The diameter of the shaft portion 731 is equal to or substantially equal to the diameter of the first hole 711. A male thread is formed on a part of the shaft portion 731, specifically, on the flange portion 733 side. For this reason, the cap 73 is fixed to the first hole 711 by screw-coupling with the female thread formed in the first hole 711. When the cap 73 is attached to the first hole 711, the shaft portion 731 is accommodated in the first hole 711, and the flange portion 733 and the head portion 732 project to the front side of the opening 711a.

[0046] As shown in FIG. 4, the protruding head portion 732 is disposed on the third axis AX3 of the fixture 720a fixed to the fixing portion 721a. More specifically, the front end portion of the head portion 732 is located in front of the third axis AX3 of the fixture 720a. It can also be said that the length from the flange portion 733 to the front end portion of the head portion 732 is longer than the length from the opening 711a to the third axis AX3.

[0047] On the first axis AX1 side (rear side) from the region where the male thread of the shaft portion 731 is formed, two grooves 731a, 731b are formed along the outer periphery. Seal members 732a, 732b such as O-rings are provided in each of the grooves 731a, 731b. The groove 731a and the groove 731b are formed with a predetermined interval in the direction along the second axis AX2. That is, the seal members 732a, 732b are provided with a predetermined interval along the second axis AX2 direction.

[0048] When the cap 73 is fixed to the first hole 711, in the direction along the second axis AX2, an air release hole 711b is located between the seal member 732a and the seal member 732b. Thereby, when the cap 73 is fixed to the first hole 711, the leakage of the gas in the pressure chamber 27 to the outside through the first hole 711 is suppressed. That is, the cap 73 closes the first hole 711 in the state of being attached to the first hole 711.

[0049] <Relief valve 74> The relief valve 74 is attached inside the first hole 711 on the first axis AX1 side (rear side) of the cap 73. The relief valve 74 has a base portion 740, a main body portion 741, and a biasing portion 742. The main body portion 741 has a diameter equal to or substantially equal to the diameter of the first hole 711. A seal member 743 such as an O-ring is attached to a groove formed along the outer periphery of the main body portion 741.

[0050] A base portion 740 is provided on the cap 73 side (front side) with respect to the main body portion 741, and a biasing portion 742 is disposed between the main body portion 741 and the base portion 740. The base portion 740 is provided on the front side of the air release hole 711b.

[0051] The biasing portion 742 is an elastic member such as a coil spring, one end portion thereof abuts against the base portion 740, and the other end portion thereof abuts against the main body portion 741. Thereby, the main body portion 741 is biased along the second axis AX2 toward the first axis AX1 side (rear side). At this time, the seal member 743 provided on the main body portion 741 is located on the first axis AX1 side (rear side) of the relief opening 711c. The relief valve 74 opens the relief opening 711c when the pressure of the gas filled from the outside into the pressure chamber 27 becomes equal to or higher than a target pressure which is a threshold value.

[0052] <Check valve 75> The check valve 75 is housed and attached below the second hole 712. The check valve 75 is composed of a first valve portion 751 and a second valve portion 752. The first valve portion 751 is rod-shaped and extends along the first axis AX1. The diameter of the first valve portion 751 is equal to or substantially equal to the inner diameter of the second region 712b of the second hole 712.

[0053] The second valve portion 752 is formed on the upper part of the first valve portion 751 and extends upward along the first axis AX1. The diameter of the second valve portion 752 is smaller towards the upper side. That is, a taper is formed on the outer circumference of the second valve portion 752.

[0054] <Cover Cap 76> The cover cap 76 is detachably attached to the chamber cover 71 from above the second hole 712. The cover cap 76 has a shaft portion 761 extending along the first axis AX1 and a flange 762 formed on the upper part of the shaft portion 761. An insertion hole 765 is formed on the upper surface of the flange 762 into which a tool 90 used to attach and detach the cover cap 76 to and from the second hole 712 is inserted. When the cover cap 76 is attached to the chamber cover 71, the shaft portion 761 is housed in the second hole 712 and the flange 762 protrudes upward from the chamber cover 71.

[0055] The diameter of the shaft portion 761 is equal to or approximately equal to the inner diameter of the second hole 712. A male thread is formed on the upper side of the shaft portion 761, which is screw-connected to the female thread formed in the second hole 712. This allows the cover cap 76 to be attached to the chamber cover 71.

[0056] The shaft portion 761 is provided with a sealing member 763, such as an O-ring, in a groove formed along its outer circumference. When the cover cap 76 is attached to the chamber cover 71, the shaft portion 761 and the second hole 712 are sealed by the sealing member 763. Additionally, a sealing member 764 is provided on the lower surface of the flange 762. When the cover cap 76 is attached to the chamber cover 71, the lower surface of the flange 762 and the upper end surface 710 of the chamber cover 71 are sealed by the sealing member 764. As a result, the second hole 712 is sealed by the cover cap 76, and leakage of gas from the pressure chamber 27 is suppressed.

[0057] <Operation of the work implement 10> An example of the operation of the work implement 10, which is a nail gun, when driving a fastener N into a mating material will be explained. If at least one of the operation of the trigger 211 and the pushing operation of the push lever 39 is turned off by the operator, the work implement 10 is controlled so that power is not supplied to the electric motor 15.

[0058] When the operator presses the push lever 39 against the workpiece and applies operating force to the trigger 211, the control unit (not shown) located inside the housing 11 controls the supply of power from the power supply unit 14 to the electric motor 15. When the drive shaft is rotated by the electric motor 15, the rotational force is transmitted to the driver blade 51 of the piston unit 12 via the transmission mechanism 17. The driving force transmitted from the electric motor 15 causes the driver blade 51 to rise from its standby position against the pressure in the pressure chamber 27.

[0059] When the driver blade 51 reaches top dead center and the rotational force from the electric motor 15 via the transmission mechanism 17 is no longer transmitted, the driver blade 51 descends due to the pressure in the pressure chamber 27. That is, the driver blade 51 moves from top dead center to bottom dead center. As the driver blade 51 descends to bottom dead center, it strikes the stopper N supplied to the injection passage 38. As a result, the stopper N is struck by the driver blade 51 and driven into the mating material. In other words, the piston portion 12 strikes the stopper N by moving to one side (downward) of the first direction AR1 due to the pressure inside the pressure chamber 27.

[0060] After the driving motion, the driver blade 51 re-engages with the transmission mechanism 17 and moves upward against the pressure in the pressure chamber 27. The driver blade 51 then moves from the bottom dead center to the standby position and stops at the standby position.

[0061] <Disassembly of Case Section 70> Referring to Figures 4 to 8, the procedure for disassembling the case section 70 during maintenance and inspection of the piston section 12 will be explained. When the worker disassembles the case section 70 by releasing the connection between the first component, the chamber cover 71, and the second component, the chamber base 72, the worker performs an opening operation. The opening operation is the operation of removing the cap 73 from the case section 70.

[0062] Figure 5 is a cross-sectional view of the pressure accumulator 18 showing the state after the top cover 24 has been removed from the state shown in Figure 4. Figure 6 is a cross-sectional view of the pressure accumulator 18 showing the state during the opening operation. Figure 7 is a cross-sectional view of the pressure accumulator 18 showing the state after the fixing device 720a has been removed following the opening operation. Figure 8 is a cross-sectional view of the pressure accumulator 18 showing the state after the case portion 70 has been disassembled. Figures 5 to 8 are cross-sectional views of the pressure accumulator 18 along the line A-A in Figure 3, similar to Figure 4.

[0063] As shown in Figure 5, the head 732 of the cap 73 is located above the fastener 720a fixed to the fixing part 721a. Therefore, in the state shown in Figure 5, if one attempts to remove the fastener 720a by inserting a tool 90, such as a hex wrench, into the insertion hole 726 provided in the head 725 of the fastener 720, the tool 90 and the head 732 of the cap 73 will interfere with each other. For this reason, the fastener 720a cannot be removed using the tool 90 before the release operation is performed. Furthermore, the vertical distance between the first fixing hole 722 into which the fastener 720a is inserted and the cap 73 is shorter than the axial length of the fastener 720a. Therefore, even if the fastener 720a could be loosened, the fastener 720a and the head 732 of the cap 73 would interfere with each other, making it impossible to pull the fastener 720a out of the first fixing hole 722. In other words, the cap 73 prevents the fastener 720a from being removed without an opening operation being performed. To put it another way, the cap 73 prevents the coupling between the first component, the chamber cover 71, and the second component, the chamber base 72, from being released without an opening operation being performed.

[0064] To disassemble the case portion 70 by releasing the connection between the chamber cover 71 and the chamber base 72, first, the cap 73 is removed from the case portion 70 by an operator's release operation. In this case, as shown in Figure 6, the tool 90 is inserted into the insertion hole 734 formed in the head 732 of the cap 73. Then, when the cap 73 is rotated via the tool 90, the cap 73 moves forward along the second axis AX2.

[0065] As the cap 73 moves, the positional relationship between the sealing members 732a and 732b provided on the shaft portion 731 and the air release hole 711b provided in the first hole 711 changes. As shown in Figure 6, when the sealing member 732a is positioned forward of the air release hole 711b, the gas in the pressure chamber 27 flows through the air release hole 711b and the gap between the shaft portion 731 and the first hole 711 as a flow path FL1 and is released to the outside of the case portion 70.

[0066] In other words, when the opening operation is performed to remove the cap 73 from the first hole 711 of the case portion 70, the gas in the pressure chamber 27 is released to the outside. The cap 73 functions as an opening that allows communication between the inside and outside of the pressure chamber 27 while the first component, the chamber cover 71, and the second component, the chamber base 72, remain connected when the opening operation is performed by the operator.

[0067] Figure 7 shows the state after the opening operation has been performed and the cap 73 has been removed from the case portion 70. After the opening operation is performed, the cap 73, which restricts the release of the coupling between the chamber cover 71 and the chamber base 72, is no longer above the fixing device 720a. That is, when the opening operation is performed, the cap 73, which is the opening part, moves to a different position on the third axis AX3. For this reason, the tool 90 can be inserted into the insertion hole 726 of the fixing device 720a. Then, using the tool 90, the fixing device 720a is pulled upward from the first fixing hole 722 and the second fixing hole 723. This releases the coupling between the chamber cover 71 and the chamber base 72. Subsequently, as shown in Figure 8, the case portion 70 is disassembled by moving the chamber cover 71 upward.

[0068] Furthermore, the fasteners 720 fixed to the fastening parts 721 other than the fastening part 721a may be removed before or after the opening operation of the cap 73.

[0069] <Assembly of Case Section 70> The assembly of the disassembled case section 70 is carried out in the reverse order of the disassembly process described above. That is, the chamber cover 71 is placed above the chamber base 72, and as shown in Figure 7, the fasteners 720 inserted from above into the first fixing hole 722 and the second fixing hole 723 are fixed using the tool 90. This connects the chamber cover 71 and the chamber base 72.

[0070] Subsequently, the cap 73 is inserted into the first hole 711 through the opening 711a. Then, as shown in Figure 6, the cap 73 is fixed in the first hole 711 by the tool 90. As a result, the case portion 70 is in the state shown in Figure 5. In this state, the pressure chamber 27 inside the case portion 70 is filled with gas.

[0071] Figure 9 is a cross-sectional view of the pressure accumulator 18 when gas is being filled into the pressure chamber 27. In this case, the cover cap 76 is removed from the chamber cover 71 using a tool 90. Then, an air hose 91 connected to an external device such as a compressor is inserted into the second hole 712. When the inserted air hose 91 comes into contact with the upper end of the check valve 75, the check valve 75 moves downward within the second hole 712. Due to the downward movement of the check valve 75, the tapered second valve portion 752 is positioned in the first region 712a of the second hole 712. As a result, a gap is created between the second hole 712 and the check valve 75, and the pressure chamber 27 is connected to the external device, allowing gas to flow into the pressure chamber 27. In other words, the check valve 75 is a filling valve that allows gas to flow into the pressure chamber 27 from outside.

[0072] In this state, the gas supplied from the external device flows into the pressure chamber 27 along the flow path FL2 and fills the pressure chamber 27. The pressure inside the pressure chamber 27 increases due to the gas filling the pressure chamber 27. When the pressure of the gas filling the pressure chamber 27 from the air hose 91 exceeds the target pressure (threshold), the relief valve 74 provided in the first hole 711, which is in communication with the second hole 712, is activated. That is, the main body 741 moves forward (towards the cap 73) against the biasing force of the biasing part 742. In other words, the biasing force of the biasing part 742 is set according to the value of the pressure that can be allowed in the pressure chamber 27.

[0073] As the main body 741 moves forward, it is positioned in front of the relief opening 711c formed in the second hole 712. As a result, the second hole 712 and the outside of the case 70 are connected via the relief opening 711c, and any excess gas supplied from the external device flows through the flow path FL3 and is released to the outside through the relief opening 711c. This prevents the pressure chamber 27 from being overfilled with gas.

[0074] Subsequently, the air hose 91 is removed, and the cover cap 76 is fixed to the upper part of the second hole 712 using the tool 90, so that the case section 70 is in the state shown in Figure 5. Then, the top cover 24 is attached to the cylinder case 20, so that the pressure accumulation section 18 returns to the state shown in Figure 4. This completes the assembly of the case section 70.

[0075] According to the first embodiment described above, at least one of the following effects can be obtained.

[0076] (1) The work machine 10 is equipped with a cap 73, which is an opening that allows communication between the inside and outside of the pressure chamber 27 while the first component, the chamber cover 71, and the second component, the chamber base 72, remain connected when opened by an operator. The cap 73 prevents the connection between the chamber cover 71 and the chamber base 72 from being released without an opening operation. In other words, the opening operation is performed when the operator releases the connection between the chamber cover 71 and the chamber base 72.

[0077] Therefore, the gas in the pressure chamber 27 can be discharged to the outside before the coupling between the chamber cover 71 and the chamber base 72 is released. In other words, the case portion 70 is prevented from being disassembled while the internal pressure of the pressure chamber 27 is higher than the air pressure. As a result, unlike configurations in which the gas in the pressure chamber 27 is discharged to the outside when the case portion 70 is being disassembled, it is possible to prevent the parts from becoming difficult to remove when the case portion 70 is disassembled, thereby improving the workability when disassembling the case portion 70.

[0078] (2) The cap 73 restricts the removal of the fastener 720 from at least one of the chamber cover 71 and the chamber base 72 without an opening operation. This prevents the case portion 70 from being disassembled when the pressure inside the pressure chamber 27 is higher than the air pressure. In other words, it prevents the parts from becoming difficult to remove when disassembling the case portion 70 due to the load caused by the pressure inside the pressure chamber 27. As a result, the workability when disassembling the case portion 70 is improved.

[0079] (3) The cap 73 is positioned on the third axis AX3 of the shaft portion 724 of the fastener 720a, and moves to a different position from the third axis AX3 when the release operation is performed. For this reason, the tool 90 for removing the fastener 720a interferes with the cap 73 unless the release operation that removes the cap 73 is performed. In other words, the fastener 720a cannot be removed and the case portion 70 cannot be disassembled. As a result, the release operation is performed before the case portion 70 is disassembled, and the gas in the pressure chamber 27 is discharged to the outside before the case portion 70 is disassembled. Therefore, it is possible to make it easier to remove parts when disassembling the case portion 70 and to improve the workability when disassembling the case portion 70.

[0080] (4) The work machine 10 has a relief valve 74 that opens when the pressure of the gas filling the pressure chamber 27 exceeds a threshold target pressure. The case portion 70 has a first hole 711 into which the relief valve 74 is attached, and a cap 73 is attached to this first hole 711. As a result, the first hole 711 can be used as the common mounting position for the cap 73 and the relief valve 74, which makes it possible to suppress the complexity and size of the structure of the pressure accumulation unit 18.

[0081] (5) The first hole 711 connects the inside and outside of the pressure chamber 27. The cap 73 closes the first hole 711 when it is attached to the first hole 711. As a result, when the cap 73 is attached to the first hole 711, a decrease in the pressure in the pressure chamber 27 is suppressed, and adverse effects on the operation of the work machine 10 are suppressed.

[0082] <Second Embodiment> The implement of the second embodiment will now be described. Hereinafter, the same reference numerals will be used for components similar to those of the implement 10 in the first embodiment, and the differences from the first embodiment will be the main focus of the description. Components that are not specifically described are the same as in the first embodiment.

[0083] Figure 10 is a plan view of the pressure accumulator 18 of the second embodiment, viewed from above. Figure 11 is a cross-sectional view of the pressure accumulator 18 along the line B-B in Figure 10. For illustrative purposes, Figure 11 also shows a cross-section of the top cover 24. The pressure accumulator 18 includes a case 70, a cap 80, a relief valve 74, and a check valve 81. The pressure accumulator 18 of the second embodiment differs from the first embodiment in that the case 70 and the top cover 24 are connected by the cap 80.

[0084] <Case section 70> Similar to the first embodiment, the case section 70 defines the pressure chamber 27 by connecting the chamber cover 71 and the chamber base 72. As shown in Figure 10, the chamber cover 71 and the chamber base 72 are connected at four locations by fasteners 720. As shown in Figure 11, the chamber cover 71 has a first hole 711 and a second hole 712, similar to the first embodiment. However, the chamber cover 71 does not have an air release hole 711b that connects the first hole 711 to the pressure chamber 27. The first hole 711 houses a relief valve 74, similar to the first embodiment.

[0085] A top cover 24 is positioned on the upper part of the case section 70. As shown in Figure 11, the top cover 24 has an opening 241 centered on the first axis AX1. A cap 80 is detachably attached to this opening 241, as will be described in detail later. As a result, the top cover 24 is attached to the upper part of the case section 70. The case section 70 is fixed to the chamber cover 71 and the chamber base 72 by fasteners 720. Therefore, the top cover 24 that constitutes the housing 11 is attached to the case section 70 so as to cover the fasteners 720.

[0086] <Cap 80> The cap 80 is inserted into the opening 241 of the top cover 24 and attached to the second hole 712. In this way, the cap 80 fixes the top cover 24 to the case portion 70. The cap 80 is formed by a first shaft portion 801, a second shaft portion 802, and a flange portion 803. The first shaft portion 801 and the second shaft portion 802 extend vertically with the first axis AX1 as the coaxial axis. The diameter of the first shaft portion 801 is equal to or approximately equal to the diameter of the second hole 712. A male thread is formed on the first shaft portion 801. The cap 80 is screw-connected to a female thread formed on the upper side of the second hole 712.

[0087] The diameter of the second shaft portion 802 is larger than the diameter of the first shaft portion 801, and smaller than the diameter of the opening 241 of the top cover 24. The second shaft portion 802 is located above the first shaft portion 801. Therefore, when the cap 80 is fixed, the second shaft portion 802 is located above the chamber cover 71.

[0088] The flange portion 803 is formed on the upper part of the second shaft portion 802. The diameter of the flange portion 803 is larger than the diameter of the opening 241. When the cap 80 is fixed, the flange portion 803 is located on the upper part of the top cover 24. That is, the lower surface of the flange portion 803 restricts the top cover 24 from coming off upward. For this reason, the top cover 24 cannot be removed unless the cap 80 is removed.

[0089] The cap 80 has a through hole 804 that extends vertically along the first axis AX1. Part of the check valve 81, which will be described later, is housed in this through hole 804. An insertion hole 805, which has a larger diameter than the through hole 804, is formed at the upper end of the through hole 804. A tool 90 is inserted into the insertion hole 805 when attaching or detaching the cap 80.

[0090] <Check Valve 81> The check valve 81 is formed by a valve body 810 having the same shape as the check valve 75 of the first embodiment and a rod 811. The valve body 810 is housed below the second hole 712, as in the first embodiment.

[0091] The rod 811 is formed in a rod shape that extends upward along the first axis AX1 from the upper end of the valve body 810. The rod 811 is housed in the through hole 804 and insertion hole 805 of the cap 80. As shown in Figure 11, the upper end of the rod 811 is located at approximately the same position as the upper end surface of the flange portion 803 of the cap 80.

[0092] The check valve 81 is positioned to be movable in the vertical direction within the second hole 712. That is, the check valve 81 is a movable part that moves along the first direction AR1 within the second hole 712, and a rod 811, which is part of the movable part, is positioned inside the insertion hole 805. In Figure 11, the valve body 810 is shown in a state where it is in a first position (first region 712a) that closes the second hole 712.

[0093] <Disassembly of Case 70> Referring to Figures 11 and 12, the procedure for disassembling the case 70 during maintenance and inspection of the piston 12 will be explained. Figure 12 is a cross-sectional view of the pressure accumulator 18 showing the state in which the cap 80 is being opened. Figure 12 is a cross-sectional view of the pressure accumulator 18 along the line B-B in Figure 10, similar to Figure 11.

[0094] As described above, the cap 80 prevents the top cover 24 from coming off. Therefore, in order to disassemble the case 70, the cap 80 must first be removed. To remove the cap 80, a tool 90 is inserted into the insertion hole 805 of the cap 80, as shown in Figure 12. In other words, the tool 90 is inserted into the insertion hole 805 when performing the opening operation.

[0095] When the tool 90 is inserted into the insertion hole 805, the upper end of the rod 811 comes into contact with the tool 90. When the rod 811 is pressed downward by the tool 90, the check valve 81 moves downward within the second hole 712. As the check valve 81 moves downward, the valve body 810 reaches the second position (second region 712b) of the second hole 712. In other words, by coming into contact with the tool 90 inserted into the insertion hole 805, the valve body 810 of the check valve 81 moves from the first position to the second position.

[0096] At this time, a gap is created between the second hole 712 and the valve body 810. When the cap 80 is rotated by the tool 90, the cap 80 moves upward. This movement creates a gap between the cap 80 and the upper end surface 710. As a result, the pressure chamber 27 and the outside of the work machine 10 are in communication through the gap between the second hole 712 and the check valve 81, the gap between the cap 80 and the chamber cover 71, and the opening 241. In other words, the check valve 81, by being in the second position, opens the second hole 712. As a result, the gas in the pressure chamber 27 flows through the path FL4 and is released to the outside of the top cover 24.

[0097] Subsequently, the cap 80 is removed from the top cover 24. That is, when the opening operation is performed to remove the cap 80 from the second hole 712, the gas in the pressure chamber 27 is released to the outside. For this reason, the cap 80 and check valve 81 of the second embodiment function as openings that allow communication between the inside and outside of the pressure chamber 27 while the first member, the chamber cover 71, and the second member, the chamber base 72, remain connected when the opening operation is performed.

[0098] When the cap 80 is removed from the top cover 24 by the opening operation, the removal of the top cover 24 is no longer restricted. In other words, the cap 80, which is the opening part, restricts the removal of the top cover 24, which constitutes the housing 11, from the case part 70 without the opening operation being performed.

[0099] Then, when the top cover 24 is removed, the pressure accumulator 18 becomes accessible for the insertion of the tool 90 into the insertion hole 726 of the fixing device 720, as shown in Figure 10. In this state, the tool 90 is inserted into the insertion hole 726 of the fixing device 720 (see Figure 10), and the fixing device 720 is pulled upward from the case portion 70 using the tool 90. This releases the connection between the chamber cover 71 and the chamber base 72. Subsequently, the case portion 70 is disassembled by moving the chamber cover 71 upward.

[0100] Since the case section 70 is disassembled by the procedure described above, it can be said that the release operation is performed in conjunction with a release operation by the operator. The release operation refers to the operation until the cap 80 is removed from the top cover 24 and the chamber cover 71, and the connection between the chamber cover 71 and the chamber base 72 is released.

[0101] <Assembly of Case Section 70> The disassembled case section 70 is assembled in the reverse order of the disassembly process described above. That is, the chamber cover 71 is placed above the chamber base 72 and the fastener 720 is fixed using the tool 90. After that, the top cover 24 is attached and the cap 80 is attached to the second hole 712 and the opening 241. In this case, the cap 80 is fixed to the second hole 712 with the tool 90, as shown in Figure 12. Once the cap 80 is fixed, the pressure accumulator 18 is reassembled, as shown in Figure 11. In this state, the pressure chamber 27 inside the case section 70 is filled with gas.

[0102] Figure 13 is a cross-sectional view of the case portion 70 when gas is filled into the pressure chamber 27. In this case, an air hose 91 connected to an external device such as a compressor is inserted into the insertion hole 805 of the cap 80. The rod 811 is pressed downward by the air hose 91 inserted into the insertion hole 805. As a result, the valve body 810 of the check valve 81 moves downward within the second hole 712. When the valve body 810 is in the second position (second region 712b), a gap is created between the second hole 712 and the valve body 810. As a result, the pressure chamber 27 and the external device are in communication through the gap between the second hole 712 and the check valve 81 and the gap between the rod 811 and the through hole 804.

[0103] In this state, the gas supplied from the external device flows through the flow path FL5 and enters the pressure chamber 27, filling the pressure chamber 27. That is, the check valve 81 functions as a filling valve that allows gas to enter the pressure chamber 27 from outside. The pressure inside the pressure chamber 27 increases due to the gas filling the pressure chamber 27. When the pressure of the gas filling the pressure chamber 27 from the air hose 91 exceeds the target pressure threshold, the relief valve 74 is activated in the same manner as in the first embodiment. That is, the second hole 712 and the outside of the case portion 70 are connected via the relief opening 711c, and any excess gas supplied from the external device flows through the flow path FL6 and is released to the outside through the relief opening 711c. As a result, the overfilling of the pressure chamber 27 with gas is suppressed.

[0104] By having the above configuration, the second embodiment also provides the following effects in addition to at least one of the effects (1) and (2) obtained in the first embodiment described above.

[0105] (6) The top cover 24 that constitutes the housing 11 is attached to the case portion 70 so as to cover the fastener 720. The cap 80, which is an opening, restricts the removal of the top cover 24 from the case portion 70 without an opening operation. As a result, the top cover 24 cannot be removed from the case portion 70 unless the cap 80 is removed by an opening operation, and therefore the case portion 70 cannot be disassembled. As a result, the gas in the pressure chamber 27 can be discharged to the outside before the case portion 70 is disassembled, making it easier to remove parts when disassembling the case portion 70 and improving the workability when disassembling the case portion 70.

[0106] (7) The work machine 10 has a check valve 81 as an opening, which is a filling valve that allows gas to flow in from outside the pressure chamber 27. A second hole 712 is formed in the case portion 70 to which the check valve 81 is attached, and the cap 80, which is the opening, and the check valve 81 are attached to the second hole 712. As a result, the second hole 712 can be used in common as the mounting position for the cap 80 and the check valve 81, which makes it possible to suppress the complexity and size of the structure of the pressure accumulation section 18.

[0107] (8) The check valve 81 functions as a movable part that closes the second hole 712, which connects the inside and outside of the pressure chamber 27, when it is in a first position (first region 712a), and opens the second hole 712 when it is in a second position (second region 712b). The cap 80 has an insertion hole 805 into which a tool 90 is inserted when performing the opening operation. At least a part of the rod 811 of the check valve 81 is positioned inside the insertion hole 805. When the tool 90 is inserted into the insertion hole 805, the check valve 81 comes into contact with the tool 90 and moves from the first position to the second position. As a result, when the tool 90 is inserted into the insertion hole 805 of the cap 80 during the opening operation, the check valve 81 moves and the air in the pressure chamber 27 is discharged to the outside. In other words, the opening operation is performed in conjunction with the release operation in which the operator releases the coupling between the chamber cover 71 and the chamber base 72. As a result, unlike configurations in which the gas in the pressure chamber 27 is discharged to the outside when the case portion 70 is disassembled, the difficulty in removing parts when disassembling the case portion 70 is suppressed, and the workability when disassembling the case portion 70 is improved.

[0108] <Modified Example> A modified working machine will now be described. Hereinafter, the same reference numerals will be used for components similar to those in the working machine 10 of the first embodiment, and the differences from the first embodiment will be the main focus of the description. Points that are not specifically described are the same as in the first embodiment. Figure 14 is a cross-sectional view of the pressure accumulator 18 of the modified working machine 10. Figure 14 is a cross-sectional view similar to the cross-sectional view of the pressure accumulator 18 shown in Figure 4, and for the sake of explanation, the top cover 24 is also shown.

[0109] The pressure accumulation section 18 of the modified work machine 10 has a cover cap 86 with a different shape from the cover cap 76 of the first embodiment. The diameter of the flange 862 of the cover cap 86 is larger than the diameter of the flange 762 of the cover cap 76 of the first embodiment. Specifically, in the radial direction centered on the axis of the shaft portion 761 of the cover cap 86 (i.e., the first axis AX1), the outer peripheral end of the flange 862 is located radially outward from the relief opening 711c. The sealing member 764 is provided on the lower surface side of the flange 862 radially outward from the relief opening 711c.

[0110] Therefore, the sealing member 764 abuts against the upper end surface 710 of the chamber cover 71 radially outward from the relief opening 711c. In other words, when the cover cap 86 is attached to the chamber cover 71, the flange 862 seals the second hole 712 and the relief opening 711c. It can also be said that the relief opening 711c is formed within the area sealed by the flange 862, the upper end surface 710, and the sealing member 764.

[0111] With the above configuration, the modified form also provides the following effects in addition to those obtained with respect to the first embodiment described above.

[0112] The relief opening 711c is sealed by the cover cap 86, which prevents dust floating around the work machine 10 from passing through the relief opening 711c and entering the pressure chamber 27, thereby improving the durability of the work machine 10. Furthermore, even if the pressure chamber 27 and the first hole 711 become connected due to damage to the chamber cover 71 or a manufacturing defect, gas leakage to the outside of the pressure chamber 27 through the relief opening 711c can be prevented.

[0113] Furthermore, the modified configuration described above can also be applied to the work machine 10 of the second embodiment. Specifically, the opening 241 of the top cover 24 shown in Figure 11, and the second shaft portion 802 and flange portion 803 of the cap 80, each have larger diameters than in the second embodiment. In the radial direction centered on the first axis AX1, the outer peripheral end of the second shaft portion 802 is located radially outward from the relief opening 711c. And, on the lower surface side of the second shaft portion 802, a sealing member is provided radially outward from the relief opening 711c.

[0114] As a result, when the cap 80 is attached, the relief opening 711c is sealed by the lower surface and upper end surface 710 of the second shaft portion 802 and the sealing member. This prevents dust from entering the pressure chamber 27 and prevents unintended leakage of gas that has passed through the relief opening 711c.

[0115] <Third Embodiment> The implement of the third embodiment will now be described. Hereinafter, the same reference numerals will be used for components similar to those of the implement 10 in the first embodiment, and the differences from the first embodiment will be the main focus of the description. Components that are not specifically described are the same as in the first embodiment.

[0116] Figure 15 is a cross-sectional view of the work machine 10 according to the third embodiment. Figure 16 is an exploded perspective view showing a part of the work machine 10. Figure 17 is a cross-sectional view along the line C-C in Figure 15.

[0117] <Housing 11> The housing 11 has a first housing 111 and a second housing 112. The first housing 111 is composed of two casings 111a and 111b, which are molded from, for example, synthetic resin. The casings 111a and 111b are fixed to each other in a butted state to form the first housing 111. More specifically, the casings 111a and 111b are fixed to each other by fixing elements such as screws. From another perspective, when the fixing by the fixing elements is released, the casings 111a and casings 111b that constitute the first housing 111 are separated.

[0118] Furthermore, the direction perpendicular to the first direction AR1 and the second direction AR2, and parallel to the direction in which the casings 111a and 111b are aligned, is called the third direction AR3. In the third direction AR3, the side of casing 111a is sometimes called the right side, and the side of casing 111b is sometimes called the left side.

[0119] As shown in Figures 16 and 17, an axial projection 111c is formed near the upper inner end of the casing 111b, projecting to the right. A hole 111d is formed at the right end of the projection 111c, aligned with the third direction AR3. A female thread is formed in the hole 111d.

[0120] An opening 113 is formed at the upper right end of the casing 111a. The second housing 112 is mounted so as to cover the opening 113. A recess 112a is formed on the outer surface of the second housing 112. The recess 112a extends to the left. A hole 112b is formed on the left end face of the recess 112a. The hole 112b is a through hole that penetrates the left end face of the recess 112a in the left-right direction.

[0121] When the second housing 112 covers the opening 113, as shown in Figure 17, the protrusion 111c of the casing 111b and the recess 112a of the second housing 112 sandwich a part of the fixing cover 87, which will be described later, from the left and right directions. That is, a part of the fixing cover 87 is positioned between the protrusion 111c and the recess 112a. In this state, the screws 114 are inserted into the holes 111d and 112b, thereby assembling and fixing the first housing 111 to the casing 111b.

[0122] As shown in Figure 16, a mounting opening 115 is formed near the upper rear end of the first housing 111. The top cover 24 is detachably attached to the first housing 111. A projection 242 is formed at the lower end 240 of the top cover 24, projecting toward the first axis AX1. The projection 242 is housed inside the mounting opening 115 formed in the first housing 111. This prevents the top cover 24 from being misaligned relative to the first housing 111 in the circumferential direction AR4 and the first direction AR1 around the first axis AX1. In other words, the projection 242 and the mounting opening 115 constitute a positioning structure 116 for the top cover 24 and the first housing 111.

[0123] Furthermore, an opening 243 is formed near the upper rear end of the top cover 24. The protrusion 71d formed on the case portion 70, which will be described later, is housed in the opening 243.

[0124] <Case section 70> Figure 18 is a cross-sectional view along the line D-D in Figure 15. Figure 19 is a cross-sectional view along the line E-E in Figure 15. Figure 20 is a cross-sectional view along the line F-F in Figure 19. Figure 21 is a cross-sectional view along the line G-G in Figure 19.

[0125] The case portion 70 constituting the pressure accumulation section 18 defines the pressure chamber 27 by coupling a first member, a chamber cover 71, and a second member, a chamber base 72, similar to the first and second embodiments. The chamber base 72 is coupled to the chamber cover 71 so as to be detachable from the chamber cover 71 by relative movement along the first axis AX1 (first direction AR1). In addition to the chamber cover 71 and chamber base 72, the case portion 70 includes a fixing device 60 and a fixing device cover 87.

[0126] <Chamber Base 72> Similar to the first and second embodiments, the chamber base 72 is, for example, cylindrical and is located above the cylinder 28, i.e., above the piston 50 which is located inside the cylinder 28. As shown in Figures 20 and 21, a flange 820 is formed at the upper end of the chamber base 72. The flange 820 is provided with an exhaust port 821. The exhaust port 821 is a through-hole that penetrates the flange 820 vertically and connects the inside of the pressure chamber 27 to the outside of the pressure chamber 27.

[0127] A projection 822 is provided on the outer circumferential wall of the flange 820, projecting radially outward. As shown in Figure 18, in a plane intersecting the vertical direction, the projection 822 is located on a straight line L1 connecting the exhaust port 821 and the center of the case portion 70 (first axis AX1).

[0128] <Chamber Cover 71> The chamber cover 71 is, as in the first and second embodiments, for example, a bottomed cylindrical shape. The chamber cover 71 is detachably attached to the upper part of the chamber base 72 by a fixing device 60, which will be described later, with its bottom surface 71a facing upward.

[0129] As shown in Figure 16, the outer circumferential wall of the chamber cover 71 has a bottom surface 71a, a side surface 71b, and a connecting wall surface 71c. The diameter of the bottom surface 71a is smaller than the diameter of the side surface 71b. The connecting wall surface 71c connects the bottom surface 71a and the side surface 71b. The cross-section of the connecting wall surface 71c at the plane intersecting the first direction AR1 is curved. A projection 71d projecting upward is formed at the rear end of the connecting wall surface 71c. When the case portion 70 is housed in the top cover 24, the projection 71d is housed in an opening 243 formed in the top cover 24. This prevents the case portion 70 from shifting position relative to the top cover 24 in the circumferential direction AR4. In other words, the projection 71d and the opening 243 constitute a positioning structure 117 for the case portion 70 and the top cover 24.

[0130] As shown in Figures 18 and 20, a groove 830 is formed in the inner circumferential wall of the chamber cover 71, extending in the vertical direction. A projection 822 formed on the chamber base 72 is accommodated in the groove 830 formed in the chamber cover 71. This prevents the chamber cover 71 and the chamber base 72 from shifting in the circumferential direction AR4. In other words, the groove 830 and the projection 822 constitute a positioning structure 118 for the chamber cover 71 and the chamber base 72.

[0131] A fixing groove 831 is formed on the inner circumferential wall of the chamber cover 71 along the circumferential direction AR 4. The fixing groove 831 is a groove that accommodates the fixing device 60, which will be described later. The diameter of the fixing groove 831 is equal to or approximately equal to the outer diameter of the fixing device 60, which will be described later. As shown in Figure 18, the area 831a near the location where the groove 830 is formed has a smaller diameter than the other areas of the fixing groove 831.

[0132] <Fixing device 60> As shown in Figure 18, the fixing device 60 is annular in shape with an intermittent portion 61 formed by cutting out a part of the circumferential AR4. The fixing device 60 is assembled into the fixing groove 831 of the chamber cover 71. An operating portion 62a and 62b (collectively referred to as operating portion 62) are provided at each end of the fixing device 60. That is, the pair of operating portions 62 are arranged so as to sandwich the intermittent portion 61. In the circumferential AR4 of the fixing device 60, the length of the intermittent portion 61 is greater than the length of the vicinity region 831a formed in the groove 830. Each of the pair of operating portions 62 has an operating hole 621 into which a tool or the like is inserted when joining or disassembling the chamber cover 71 and the chamber base 72.

[0133] When the fastener 60 is assembled to the chamber cover 71, the proximity region 831a formed in the groove 830 is located within the intermittent portion 61. As described above, the diameter of the proximity region 831a is smaller than the diameter of other regions of the fastening groove 831. Therefore, the proximity region 831a restricts the movement of the fastener 60 along the circumferential direction AR4 relative to the chamber cover 71. In other words, the proximity region 831a functions as a positioning structure for the fastener 60.

[0134] As shown in Figures 20 and 21, the fastener 60 is assembled to the chamber cover 71 with its outer edge housed in a fixing groove 831 formed in the chamber cover 71, and protruding inward from the inner circumferential wall of the chamber cover 71. The upper surface 600 of the fastener 60 abuts against the lower surface 823 of the outer edge of the flange 820 of the chamber base 72. This restricts the movement of the chamber base 72 downward relative to the chamber cover 71. In other words, the fastener 60, when assembled to the fixing groove 831 of the chamber cover 71, is a retaining ring that restricts the relative movement of the chamber base 72 along the direction of the first axis AX1 (first direction AR1) relative to the chamber cover 71.

[0135] <Fixing Cover 87> Figure 22 is a cross-sectional view of the fixing cover 87. The fixing cover 87 is detachably attached to the exhaust port 821 formed in the chamber base 72 and the casing 111b of the first housing 111.

[0136] The fastener cover 87 has a cover portion 870, a first cap 871, a second cap 872, and a mounting portion 873. The cover portion 870 is plate-shaped and extends in a direction intersecting the first direction AR1. As shown in Figure 19, the cover portion 870 is arc-shaped in the plane intersecting the first direction AR1, corresponding to the shape of the cylindrical chamber cover 71 and chamber base 72.

[0137] Furthermore, it is preferable that the angle between the straight line connecting one end of the arc-shaped cover portion 870 to the center (first axis AX1) and the straight line connecting the other end of the cover portion 870 to the center (first axis AX1) is 45 degrees or more. Specifically, in the circumferential direction AR4, the length of the cover portion 870 is greater than the distance between the operating portion 62a and the end of the exhaust port 821 on the operating portion 62b side.

[0138] A mounting opening 874 is formed at one end of the cover portion 870. The first cap 871 and the second cap 872 are attached to the mounting opening 874. A mounting portion 873 is provided at the other end of the cover portion 870. The mounting portion 873 extends downward from the lower surface of the cover portion 870. A fixing opening 875 is formed near the lower end of the mounting portion 873. The fixing opening 875 is a through hole that penetrates the mounting portion 873 in the left-right direction.

[0139] The first cap 871 is detachably attached to an exhaust port 821 formed in the chamber base 72, as will be described in detail later. The first cap 871 has a first cap shaft portion 92 and a flange 93 formed on the first cap shaft portion 92. The first cap shaft portion 92 is columnar along the first direction AR1. The diameter of the first cap shaft portion 92 is equal to or approximately equal to the diameter of the exhaust port 821. A fastening hole 921 with an internal thread is provided on the lower side of the first cap shaft portion 92.

[0140] The second cap 872 has a second cap shaft portion 94, a protruding shaft portion 95, and a flange 96 formed on the second cap shaft portion 94. The second cap shaft portion 94 and the protruding shaft portion 95 are columnar in shape along the first direction AR1. The protruding shaft portion 95 is a male thread provided above the second cap shaft portion 94. The diameter of the second cap shaft portion 94 is equal to or approximately equal to the diameter of the fastening hole 921.

[0141] The first cap 871 and the second cap 872 are attached by sandwiching the cover portion 870 from above and below. Specifically, the protruding shaft portion 95 of the second cap 872, which is inserted into the mounting opening 874 from below, and the fastening hole 921 of the first cap 871, which is located below the mounting opening 874, interlock with each other. The first cap 871 and the second cap 872 may be further fixed to each other by applying adhesive as needed.

[0142] <Mounting state of the fixing cover 87> Next, with reference to Figures 17, 19, and 20, the mounting state of the fixing cover 87 attached to the chamber base 72 will be described. As shown in Figure 20, the upper side of the first cap shaft portion 92 formed on the first cap 871 of the fixing cover 87 is inserted into the exhaust hole 821. At this time, the sealing member 931 such as an O-ring provided on the upper side of the flange 93 of the first cap 871 comes into contact with the stepped portion 821a inside the exhaust hole 821. As a result, the pressure chamber 27 is isolated from the outside. That is, the release of air from the pressure chamber 27 to the outside is suppressed.

[0143] As shown in Figure 20, when the first cap 871 is inserted into the exhaust port 821, the cover portion 870 is positioned below the fastener 60. Also, as shown in Figure 17, the mounting portion 873 extending downward from the lower surface of the cover portion 870 is sandwiched from the left and right by the protrusion 111c provided on the casing 111b and the recess 112a of the second housing 112.

[0144] A screw 114 is inserted into the fixing opening 875 formed in the mounting portion 873 to fix the second housing 112 to the casing 111b of the first housing 111. In other words, the fixing cover 87 and the second housing 112 are fixed to the first housing 111 by the screw 114. This prevents the fixing cover 87 from shifting position in the circumferential direction AR4 relative to the housing 11. That is, the mounting portion 873, the 111c and hole 111d of the first housing 111, the hole 112b of the second housing 112, and the screw 114 constitute a positioning structure 119 for the fixing cover 87 and the housing 11.

[0145] As described above, the cover portion 870 is located below the fixing device 60. Also, as described above, the positioning structure 116 suppresses misalignment between the first housing 111 and the top cover 24. The positioning structure 117 suppresses misalignment between the top cover 24 and the case portion 70. The positioning structure 118 suppresses misalignment between the chamber cover 71 and the chamber base 72. The proximity region 831a, which functions as a positioning structure, suppresses misalignment between the chamber cover 71 and the fixing device 60. In other words, the fixing device 60 is provided on the chamber cover 71 in a state where misalignment with respect to the first housing 111 is suppressed. Furthermore, the positioning structure 119 suppresses misalignment of the fixing device cover 87 with respect to the first housing 111 and the second housing 112. For this reason, the cover portion 870 is positioned in a state where misalignment in the circumferential direction AR4 with respect to the fixing device 60 is suppressed.

[0146] As described above, in the circumferential direction AR4, the length of the cover portion 870 is greater than the distance between the operating portion 62a and the end of the exhaust port 821 on the operating portion 62b side. The cover portion 870 is positioned such that displacement in the circumferential direction AR4 is suppressed relative to the fixing device 60. As a result, as shown in Figure 19, the operating portion 62a is covered by the cover portion 870 from below. In other words, the fixing device cover 87 is positioned to enter the intermittent portion 61 while the movement of the chamber base 72 in the first direction AR1 is restricted by the fixing device 60 assembled to the chamber cover 71. This restricts the insertion of a tool into the operating hole 621 of the operating portion 62a and the operation of the operating portion 62 when the release of air from the pressure chamber 27 to the outside is suppressed.

[0147] <Disassembly of Case Section 70> Referring to Figures 23 to 27, the process for disassembling the case section 70 of the pressure accumulator 18 will be explained. Figures 23 to 27 are perspective views of a portion of the upper part of the work machine 10, viewed from below.

[0148] Figure 23 shows the work machine 10 before the process for disassembling the case portion 70 begins. In this state, a tool is inserted by the worker into the recess 112a of the second housing 112, and the screw 114 is removed. This releases the fastening between the first housing 111, the second housing 112, and the fastener cover 87.

[0149] Figure 24 shows the work machine 10 with the top cover 24 and the second housing 112 removed. With the second housing 112 detached from the first housing 111, the fastener cover 87 and a portion of the fastener 60 are exposed to the outside through the opening 113 formed in the casing 111a. In other words, when the second housing 112 and the first housing 111 are fastened together, the second housing 112 is positioned to cover the pair of operating parts 62 formed on the fastener 60.

[0150] As described above, the fastener cover 87 is assembled to the first housing 111 such that the cover portion 870 covers the operating portion 62a provided on the fastener 60. Therefore, insertion of a tool into the operating hole 621 of the operating portion 62a is restricted. In other words, operation to remove the fastener 60 assembled to the chamber cover 71 is restricted. Thus, it can be said that the fastener cover 87 restricts the release of the connection between the chamber cover 71 and the chamber base 72.

[0151] The fastener cover 87 is in a state where it can be removed from the work machine 10 because its fastening to the first housing 111 has been released. Specifically, when a downward force is applied to the fastener cover 87 by the operator, the first cap 871 is pulled out from the exhaust port 821, and the fastener cover 87 is removed from the work machine 10. In the following description, the operation by which the operator removes the fastener cover 87 will be referred to as the release operation.

[0152] Figure 25 shows the work machine 10 after the opening operation. With the fixing cover 87 removed, the pair of operating parts 62 of the fixing device 60, the operating holes 621 formed in each of the operating parts 62, and the exhaust hole 821 are exposed to the outside through the opening 113. With the exhaust hole 821 exposed to the outside, the inside and outside of the pressure chamber 27 are connected, and the gas in the pressure chamber 27 is released to the outside.

[0153] However, since the fixing device 60 is assembled to the chamber cover 71, the chamber cover 71 and the chamber base 72 remain connected. Therefore, the fixing device cover 87 and the exhaust port 821 can be said to be an opening that allows communication between the inside and outside of the pressure chamber 27 while the first component, the chamber cover 71, and the second component, the chamber base 72, remain connected when opened by an operator.

[0154] Furthermore, as explained with reference to Figure 24, before the opening operation is performed, the fixing cover 87 restricts operation on the fixing 60, preventing the coupling between the chamber cover 71 and the chamber base 72 from being released. Therefore, it can be said that the fixing cover 87, which constitutes the opening section, restricts the coupling between the first member, the chamber cover 71, and the second member, the chamber base 72, from being released without the opening operation being performed.

[0155] As shown in Figure 25, when the opening operation is performed, the fixing cover 87 that constitutes the opening does not cover the operating part 62a. In this state, a tool is inserted into each of the pair of operating parts 62, and the pair of operating parts 62 are operated. In this case, a force is applied to operating part 62a along the operating direction AR5, and a force is applied to operating part 62b along the operating direction AR6. As a result, the shape of the fixing part 60 along the circumferential direction AR4 is deformed, and the fixing part 60 detaches from the fixing groove 831 of the chamber cover 71. In other words, the fixing part 60 can be detached from the chamber cover 71 by operating the pair of operating parts 62.

[0156] Figure 26 shows the work machine 10 after the fastener 60 has been detached from the chamber cover 71. With the fastener 60 removed, the chamber base 72 can move along the first direction AR1 relative to the chamber cover 71. In other words, it becomes possible to release the connection between the chamber cover 71 and the chamber base 72.

[0157] Figure 27 shows the work machine 10 after the coupling between the chamber cover 71 and the chamber base 72 has been released and the chamber cover 71 has been removed. The chamber cover 71 is removed by pulling it upward along the first direction AR1. At this time, the projection 822 formed on the chamber base 72 moves along the groove 830 formed on the chamber cover 71 in the first direction AR1. Once the chamber cover 71 is removed, the inside of the cylinder 28 supported by the cylinder case 20 is exposed. As a result, the components arranged inside the cylinder 28 can be removed from the upper end of the cylinder 28 to the outside of the work machine 10.

[0158] Figure 28 is a perspective view showing the internal components of the cylinder 28 being removed from the work machine 10. In Figure 28, the top cover 24, the second housing 112, and the chamber cover 71 are also shown. As shown in Figure 28, the piston 50 and driver blade 51 of the piston section (striking section) 12 located inside the cylinder 28, along with the bumper 35, are pulled out from the upper end of the cylinder 28. This makes it possible to easily perform maintenance and inspection of the piston section 12.

[0159] Furthermore, the bumper 35 is a component that is susceptible to damage from impacts by the piston 50, and therefore requires periodic replacement. In this embodiment, the bumper 35 can be pulled out from the upper end of the cylinder 28, and a new bumper 35 can be placed inside the cylinder 28 from the upper end. Therefore, the replacement of the bumper 35 can be easily performed. In this embodiment, as shown in Figure 15, the outer diameter of the bumper 35 is approximately the same as the inner diameter of the cylinder 28.

[0160] <Assembly of Case Section 70> The disassembled case section 70 is assembled in the reverse order of the disassembly process described above. After the striking section 12 and the bumper 35 are positioned inside the cylinder 28, the chamber cover 71 and the chamber base 72 are joined together. In this case, after the groove 830 of the chamber cover 71 and the protrusion 822 of the chamber base 72 are aligned, the operator moves the chamber cover 71 so that it approaches the chamber base 72 along the first direction AR1. As a result, the work machine 10 is in the state shown in Figure 26.

[0161] Subsequently, the worker operates a pair of operating parts 62 on the fixing device 60, thereby housing the fixing device 60 in the groove 830 of the chamber cover 71. In this case as well, operating part 62a is operated in the operating direction AR5, and operating part 62b is operated in the operating direction AR6. As a result, the shape of the fixing device 60 along the circumferential direction AR4 is deformed, making it possible to house it in the groove 830. Consequently, as shown in Figure 25, the fixing device 60 is assembled to the chamber cover 71, and the chamber cover 71 and the chamber base 72 are joined together.

[0162] A fixing device cover 87 is attached to the chamber base 72, which is coupled to the chamber cover 71. The first cap 871 of the fixing device cover 87 is inserted into the exhaust hole 821 formed in the chamber base 72. As a result, as shown in Figure 24, the fixing device cover 87 is positioned below the chamber base 72 with the cover portion 870 of the fixing device cover 87 entering the intermittent portion 61 of the fixing device 60. That is, the operating portion 62a of the fixing device 60 is covered by the cover portion 870.

[0163] After the fixing cover 87 is positioned below the chamber base 72, the second housing 112 is attached to the first housing 111. At this time, the second housing 112 is positioned to cover the opening 113 of the first housing 111. With the second housing 112 in place, the mounting portion 873 of the fixing cover 87 is sandwiched from the left and right by the protrusion 111c of the first housing 111 and the recess 112a of the second housing 112.

[0164] In this state, the fastener cover 87 and the second housing 112 are fixed to the first housing 111 by inserting and fastening the screws 114 into the hole 112b of the recess 112a, the fixing opening 875 of the mounting portion 873, and the hole 111d of the protruding portion 111c. After the second housing 112 is attached, the top cover 24 is attached to the first housing 111 and the second housing 112. As a result, the case portion 70 is housed inside the housing 11, and the assembly of the case portion 70 is completed.

[0165] By having the above configuration, the third embodiment provides the following effects in addition to at least one of the effects (1) and (2) obtained in the first embodiment described above.

[0166] (9) The second component, the chamber base 72, can be detached from the chamber cover 71 by moving relative to the first component, the chamber cover 71, in the direction along the first axis AX1 (first direction AR1). The fastener 60 is a retaining ring that is assembled to the chamber cover 71 and restricts the relative movement of the chamber base 72 relative to the chamber cover 71 in the direction along the first axis AX1. This makes it possible to detachably assemble the chamber cover 71 and the chamber base 72 with a simple configuration.

[0167] (10) The retaining ring, the fastener 60, is annular in shape and has an intermittent portion 61 in part of the circumferential direction AR4. The fastener cover 87, which constitutes the open portion, is positioned to enter the intermittent portion 61 when the fastener 60 restricts the relative movement of the chamber base 72. As a result, the cover portion 870 of the fastener cover 87 can cover the exhaust port 821 and the operating portion 62a located in the intermittent portion 61. Therefore, the fastener cover 87 prevents air from being released from the exhaust port 821 in the pressure chamber 27 and restricts the operation of the operating portion 62a.

[0168] (11) The fastener 60 has a pair of operating parts 62 arranged to sandwich the intermittent section 61, and can be detached from the chamber cover 71 by operating the pair of operating parts 62. The fastener cover 87 that constitutes the opening is assembled to the chamber cover 71 so as to cover the operating parts 62a, and does not cover the operating parts 62a when the opening operation is performed. In other words, if the fastener cover 87 is not removed by the opening operation, the fastener cover 87 restricts operation of the operating parts 62. For this reason, the opening operation is required when the worker releases the connection between the chamber cover 71 and the chamber base 72. Consequently, the opening operation is performed before the connection between the chamber cover 71 and the chamber base 72 is released, and the gas in the pressure chamber 27 can be discharged to the outside. As a result, the case section 70 is prevented from being disassembled when the pressure inside the pressure chamber 27 is higher than the air pressure. In other words, the difficulty in removing parts when disassembling the case section 70 is suppressed, and the workability when disassembling the case section 70 is improved.

[0169] (12) The housing 11 comprises a first housing 111 and a second housing 112 that is positioned to cover a pair of operating parts 62 and is detachable from the first housing 111. This allows the pair of operating parts 62 to be operated by disassembling a part of the housing 11. In other words, since it is not necessary to disassemble the entire housing 11, the workability when disassembling the case part 70 is improved.

[0170] Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0171] The device may have a mechanism that prevents the coupling between the chamber cover 71 and the chamber base 72 from being released when the pressure in the pressure chamber 27 is high. For example, the cap 73 in the first embodiment can be structured to move in the front-rear direction according to the pressure in the pressure chamber 27. In this case, when the pressure in the pressure chamber 27 is high, the cap 73 moves forward and is positioned above the third axis AX3 of the fixing device 720a. Therefore, when the pressure in the pressure chamber 27 is high, the tool 90 cannot be inserted into the insertion hole 726 of the fixing device 720a, as in the first embodiment, and the disassembly of the case portion 70 is restricted. When the pressure in the pressure chamber 27 is low, the cap 73 moves backward and is separated from the top of the third axis AX3 of the fixing device 720a. Therefore, when the pressure in the pressure chamber 27 is low, the tool 90 can be inserted into the insertion hole 726 of the fixing device 720a, and the restriction on disassembly of the case portion 70 is released. As a result, when the chamber cover 71 and the chamber base 72 are disassembled, the release of gas from the pressure chamber 27 to the outside is suppressed, and, as in the first and second embodiments, improved workability is possible.

[0172] 10...Working machine, 11...Housing, 12...Piston section, 18...Pressure accumulation section, 24...Top cover, 27...Pressure chamber, 28...Cylinder, 50...Piston, 51...Driver blade, 60...Fixing device, 61...Intermittent section, 62, 62a, 62b...Operating section, 70...Case section, 71...Chamber cover, 72...Chamber base, 73, 80...Cap, 74...Relief valve, 75, 81...Check valve, 76, 86...Cover cap, 87...Fixing device cover, 90...Tool, 111...First housing G, 112...Second housing, 711...First hole, 711b...Air release hole, 711c...Relief opening, 712...Second hole, 712a...First area, 712b...Second area, 720, 720a...Fixing device, 724...Shaft part, 805...Insertion hole, 810...Valve body, 811...Rod, 821...Exhaust hole, 830...Groove, 831...Fixing groove, 870...Cover part, 871...First cap, 872...Second cap, 873...Mounting part, AR1...First direction, AX1...First axis, AX3...Third axis, N...Fastener

Claims

1. A work machine comprising: a case portion including a first member and a second member, wherein the first member and the second member are joined together to define a pressure chamber inside; a striking portion that strikes a fastener by moving to one side in a first direction due to the pressure of the gas inside the pressure chamber; and an opening portion that, when opened by an operator, allows communication between the inside and outside of the pressure chamber while the first member and the second member remain joined, wherein the opening portion restricts the coupling between the first member and the second member from being released without the opening operation being performed.

2. The work machine according to claim 1, comprising a fastener connecting the first member and the second member, wherein the opening portion restricts the fastener from being removed from at least one of the first member and the second member without the opening operation being performed.

3. The work machine according to claim 2, wherein the fixing device has a shaft portion on which a male screw is formed to be screwed into at least one of the first member and the second member, and the opening portion is positioned on the axis of the shaft portion and moves from the axis to a different position when the opening operation is performed.

4. The work machine according to claim 2, wherein the opening operation is an operation to remove the opening portion from the first member and the second member.

5. The work machine according to claim 2, wherein the work machine has a housing attached to the case portion so as to cover the fixing device, and the opening portion restricts the housing from being removed from the case portion without the opening operation being performed.

6. The work machine according to claim 1, comprising a relief valve that opens when the pressure of the gas filling the pressure chamber exceeds a threshold, the case portion having a first hole to which the relief valve is attached, and the opening portion being attached to the first hole.

7. The work machine according to claim 6, wherein the first hole connects the inside and outside of the pressure chamber, and the opening closes the first hole when attached to the first hole.

8. The work machine according to claim 1, wherein the opening portion has a filling valve into which gas can flow from outside the pressure chamber, and the case portion has a second hole into which the filling valve is attached.

9. The work machine according to claim 8, wherein the second hole communicates the inside and outside of the pressure chamber, the filling valve has a movable part that closes the second hole when in a first position and opens the second hole when in a second position, the opening part has an insertion hole into which a tool is inserted when the opening operation is performed, and at least a part of the movable part is located inside the insertion hole, and when the tool is inserted into the insertion hole it comes into contact with the tool and moves from the first position to the second position.

10. The work machine according to claim 1, wherein the release operation is performed in conjunction with a release operation in which an operator releases the engagement between the first member and the second member.

11. A work machine comprising: a case portion including a first member and a second member, wherein the first member and the second member are joined together to define a pressure chamber inside; a striking portion that strikes a fastener by moving to one side in a first direction due to the pressure of the gas inside the pressure chamber; and an opening portion that allows communication between the inside and outside of the pressure chamber while the first member and the second member remain joined together, wherein the opening operation is performed when the operator releases the connection between the first member and the second member.

12. A work machine according to claim 2, wherein the first member is cylindrical, the second member is detachable from the first member by relative movement in the axial direction of the first member, and the fixing device is a retaining ring that is assembled to the first member to restrict the relative movement of the second member in the axial direction of the first member.

13. The work machine according to claim 12, wherein the retaining ring is annular having an intermittent portion in a part in the circumferential direction, and the opening portion is arranged to enter the intermittent portion when the retaining ring restricts the relative movement of the second member.

14. A work machine according to claim 13, wherein the retaining ring has a pair of operating parts arranged to sandwich the intermittent portion, and the pair of operating parts can be operated to detach it from the first member, and the opening portion is assembled to the first member so as to cover the operating parts, and does not cover the operating parts when the opening operation is performed.

15. The work machine according to claim 14, comprising a housing that covers at least a part of the case portion, wherein the housing comprises a first housing and a second housing that is arranged to cover the pair of operating portions and is detachable from the first housing.

16. A work machine comprising: a case portion including a first member and a second member, wherein the first member and the second member are joined together to define a pressure chamber inside; a striking portion that strikes a fastener by moving to one side in a first direction due to the pressure of the gas inside the pressure chamber; an open portion that allows communication between the inside and outside of the pressure chamber while the first member and the second member remain joined together; and a fixing device that connects the first member and the second member, wherein the first member is cylindrical, the second member is detachable from the first member by relative movement in the axial direction of the first member, the fixing device is a retaining ring that is assembled to the first member to restrict the relative movement of the second member in the axial direction of the first member, the retaining ring is annular with an intermittent portion in a part of the circumferential direction, and the open portion is positioned to enter the intermittent portion when the retaining ring restricts the relative movement of the second member.

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