Work machine

Abstract

The utility model provides an operation machine, which can improve the convenience of the operation machine. A nailing machine (10) is provided with: a hollow case part including a cylinder (27); and a piston part (28) which defines a pressure chamber (26) in the interior of the housing part, and which strikes a fixture by moving downward by the pressure of the gas in the pressure chamber (26). The piston section (28) has: a base member having a side wall; an X-ring (41) attached to the base member so as to be interposed between the side wall and a cylinder (27); and an O-ring (42) that is interposed between the side wall and the cylinder (27) and that is mounted at a different position in the vertical direction (M1) with respect to the X-ring (41). The X-ring (41) has a first base part and a lip part that is provided upright from the first base part and that is in contact with the cylinder (27), and the O-ring (42) has a second base part and does not have a lip part that is provided upright from the second base part.

Description

Technical Field

[0001] The utility model relates to a working machine such as a nailer. Background Art

[0002] As an example of a working machine, there is known a nailer having a cylindrical cylinder, a piston reciprocating in the cylinder, a striking portion for striking a fixing member by downward movement of the piston, and a sealing member provided on the piston.

[0003] As the nailer described above, for example, Patent Document 1 discloses a working machine (nailer) having an X-ring provided on the piston as the sealing member.

[0004] [Prior Art Documents]

[0005] [Patent Documents]

[0006] Patent Document 1: International Publication No. 2018 / 100943 Summary of the Utility Model

[0007] [Problems to be Solved by the Utility Model]

[0008] In the nailer described in Patent Document 1, in order to suppress air leakage on the contact surface between the piston and the cylinder, an X-ring is provided on the piston as a sealing member. However, at low temperatures, the X-ring hardens, so the sealing performance of the X-ring sometimes deteriorates.

[0009] Regarding the decrease in the sealing performance of the X-ring at low temperatures, if the interference amount of the X-ring with respect to the inner wall of the cylinder (the ratio of the compression amount to the wire diameter of the X-ring) is increased, improvement can be obtained. However, in this case, the lubricant coated on the inner wall of the cylinder will be scraped off, and oil film breakage will occur at normal temperatures. If oil film breakage occurs, the sealing performance improved by the oil film will decrease, resulting in air leakage.

[0010] If air leakage occurs, the operator must interrupt the nailing operation to replenish air. As a result, the convenience of the nailer may be impaired.

[0011] An object of the present utility model is to provide a working machine with improved convenience.

[0012] [Technical Means for Solving the Problem]

[0013] An operating machine according to an embodiment includes: a hollow-shaped housing portion including a cylinder, the cylinder being in a cylindrical shape extending in a first direction and having an inner wall; and a piston portion capable of moving in the first direction inside the cylinder, cooperating with the housing portion to define a pressure chamber inside the housing portion, and moving toward one side in the first direction by the pressure of the gas inside the pressure chamber, thereby striking a fixing member. The piston portion has: a base member having a side wall facing the inner wall of the cylinder; a first sealing member mounted on the base member so as to be interposed between the side wall and the inner wall; and a second sealing member mounted on the base member so as to be interposed between the side wall and the inner wall and arranged at a different position in the first direction with respect to the first sealing member. The first sealing member has a first base portion and a lip portion erected from the first base portion and contacting the cylinder in a cross-sectional view parallel to the first direction. The second sealing member has a second base portion and does not have a lip portion erected from the second base portion in the cross-sectional view.

[0014] In one embodiment, the abutting force of the first sealing member against the cylinder is greater than the abutting force of the second sealing member against the cylinder.

[0015] In one embodiment, the interference amount of the first sealing member with respect to the cylinder is greater than the interference amount of the second sealing member with respect to the cylinder.

[0016] In one embodiment, the first sealing member is arranged on the other side in the first direction relative to the second sealing member.

[0017] In one embodiment, the mechanical strength of the first sealing member is higher than that of the second sealing member.

[0018] In one embodiment, the cold resistance of the second sealing member is higher than that of the first sealing member.

[0019] In one embodiment, in the cross-sectional view of the first sealing member, the protruding direction in which the lip portion of the first sealing member protrudes from the first base portion is inclined with respect to the radial direction such that the outside of the lip portion in the radial direction of the cylinder faces the other side in the first direction.

[0020] In one embodiment, in the cross-sectional view of the first sealing member, the thickness of the lip portion in the orthogonal direction orthogonal to the protruding direction in which the lip portion of the first sealing member protrudes from the first base portion is smaller than the minor diameter of the first base portion.

[0021] In one embodiment, in the cross-section of the first sealing member, the length of the lip portion of the first sealing member protruding from the first base portion in the protruding direction is equal to the thickness of the lip portion in the orthogonal direction orthogonal to the protruding direction.

[0022] The working machine according to another embodiment includes: a hollow-shaped housing portion including a cylinder, the cylinder being in a cylindrical shape extending in a first direction and having an inner wall; and a piston portion capable of moving in the first direction inside the cylinder, cooperating with the housing portion to define a pressure chamber inside the housing portion, and moving toward one side in the first direction by the pressure of the gas inside the pressure chamber, thereby hitting a fixing member. The piston portion has: a base member having a side wall facing the inner wall of the cylinder; a first sealing member mounted on the base member so as to be interposed between the side wall and the inner wall; and a second sealing member mounted on the base member so as to be interposed between the side wall and the inner wall and disposed on the side in the first direction closer than the first sealing member. The abutting force of the first sealing member against the cylinder is greater than the abutting force of the second sealing member against the cylinder.

[0023] In another embodiment, the interference amount of the first sealing member with respect to the cylinder is greater than the interference amount of the second sealing member with respect to the cylinder.

[0024] [Effects of the utility model]

[0025] According to the present utility model, the convenience of the working machine can be improved. Description of the drawings

[0026] Figure 1 It is a cross-sectional view showing the structure of the working machine according to the embodiment of the present utility model as viewed from the side.

[0027] Figure 2 It is as viewed from the front Figure 1 A cross-sectional view of the structure of the working machine shown.

[0028] Figure 3 It shows being assembled to Figure 1 A partial enlarged cross-sectional view of the piston and its peripheral structure of the working machine shown.

[0029] Figure 4 It shows being provided at Figure 3 A perspective view of the shape of the X-ring of the piston shown.

[0030] Figure 5 It shows Figure 4 A side view of the shape of the X-ring shown.

[0031] Figure 6is a sectional view showing a structure cut along line A-A along Figure 5 shown.

[0032] Figure 7 is a magnified sectional view showing the structure of part B of Figure 6 shown.

[0033] Figure 8 is a sectional view showing the shape of an O-ring provided on the piston shown in Figure 3 shown.

[0034] Figure 9 is a partial sectional view showing the interference amount of the O-ring shown in Figure 8 shown.

[0035] Figure 10 is a partial magnified sectional view showing the structure of a piston provided with a sealing member of a first modified example in Figure 3 shown.

[0036] Figure 11 is a partial magnified sectional view showing the shape of the sealing member (V-ring) of the first modified example shown in Figure 10 shown.

[0037] Figure 12 is a partial magnified sectional view showing the structure of a piston provided with a sealing member (D-ring) of a second modified example in Figure 3 shown.

[0038] [Description of symbols]

[0039] 10: Stapler (working machine)

[0040] 11: Housing

[0041] 12: Striking part

[0042] 13: Nose

[0043] 14: Power supply part

[0044] 15: Electric motor

[0045] 17: Hoisting mechanism

[0046] 18: Accumulator

[0047] 19: Cylinder housing

[0048] 20: Handle

[0049] 21: Motor housing

[0050] 22: Assembly part

[0051] 23: Cover

[0052] 24: Bracket

[0053] 25: Hood

[0054] 26: Pressure chamber

[0055] 27: Cylinder

[0056] 27a: Inner wall

[0057] 28: Piston part

[0058] 28a: Base member

[0059] 28b: Side wall

[0060] 28c, 28d: Groove part

[0061] 28e: Bottom surface

[0062] 29: Driving blade

[0063] 29a: Rack

[0064] 30: Object material

[0065] 31: Buffer support part

[0066] 31a: Guide hole

[0067] 32: Injection part

[0068] 33: Cylindrical part

[0069] 35: Buffer

[0070] 36: Guide hole

[0071] 37: Injection passage

[0072] 38: Bearing

[0073] 39: Rotor

[0074] 40: Stator

[0075] 41: X-ring (first sealing member)

[0076] 41a: Base (first base)

[0077] 41b, 41c: Lip

[0078] 41d: Sealing surface

[0079] 42: O-ring (second sealing member)

[0080] 42a: Base (second base)

[0081] 42b: Sealing surface

[0082] 43, 44: Sliding ring

[0083] 45: Reduction mechanism

[0084] 46: Rotating shaft

[0085] 47: Motor shaft

[0086] 48: V-ring (first sealing member)

[0087] 48a: Base (first base)

[0088] 48b: Lip

[0089] 48c: Sealing surface

[0090] 49: D-ring (second sealing member)

[0091] 49a: Base (second base)

[0092] 49b: Sealing surface

[0093] 50: Pinwheel

[0094] 50a: Roller pin

[0095] 71: Trigger switch

[0096] 72: Position detection switch

[0097] 73: Control unit

[0098] 75: Trigger

[0099] 76: Housing case

[0100] 77: Magazine

[0101] 78: Staple (fastening member)

[0102] 79: Pusher rod

[0103] A1, A2: Center line

[0104] D1: Staple driving direction

[0105] D2: Return direction

[0106] E1: Rotation direction

[0107] G1: Protrusion direction

[0108] H1: Height

[0109] J1: Radial direction

[0110] K1: Orthogonal direction

[0111] L1: Length

[0112] M1: Vertical direction (first direction)

[0113] N1: Front - rear direction

[0114] P1: Minor diameter

[0115] R1: Left - right direction

[0116] T1: Thickness

[0117] W1: Wire diameter Detailed implementation mode

[0118] Refer to the accompanying drawings to illustrate a representative implementation mode of the nail - driving machine (working machine) of the present utility model.

[0119] (Implementation mode)

[0120] Figure 1 And Figure 2 The nail - driving machine 10 shown is an air - compression type working machine also called a nail - hammering machine or the like, and has a housing 11, a striking part 12, a nose part 13, a power supply part 14, an electric motor 15, a hoisting mechanism 17, and a pressure - accumulating container 18. The housing 11 is an outer - shell element of the nail - driving machine 10 and has a cylinder housing 19, a handle 20, a motor housing 21, and an assembly part 22. The cylinder housing 19 is cylindrical, and the handle 20 and the motor housing 21 are connected to the cylinder housing 19. Moreover, the assembly part 22 is connected to the handle 20 and the motor housing 21.

[0121] The power supply part 14 can be mounted on the assembly part 22 and detached from the assembly part 22. The electric motor 15 is disposed within the motor housing 21. A head cover 25 is provided on the cylinder housing 19, and the pressure - accumulating container 18 is disposed throughout the inside of the cylinder housing 19 and the inside of the head cover 25.

[0122] Furthermore, within the cylinder housing 19, a cylindrical cylinder 27 extending in the vertical direction (first direction) M1 is accommodated. The pressure - accumulating container 18 is a container having a lid 23 and a bracket 24 mounted on the cylinder 27, and is a container that closes the upper (other) side end of the cylinder 27 in the vertical direction (first direction) M1 and whose inside communicates with the inside of the cylinder 27. The cylinder 27 is made of metal, for example, made of aluminum or iron. The cylinder 27 is positioned in the direction along the center line A1 and in the radial direction with respect to the cylinder housing 19. The center line A1 passes through the center of the cylinder 27. The radial direction is the radial direction of an imaginary circle centered on the center line A1.

[0123] Moreover, a pressure chamber 26 is formed throughout the accumulator vessel 18 and within the cylinder 27. Specifically, the accumulator vessel 18 and the cylinder 27 are hollow shell parts, and a compressed gas is filled in the pressure chamber 26 formed throughout the accumulator vessel 18 and the cylinder 27. In addition to air, inert gases can also be used as the compressed gas. As an example, the inert gases include nitrogen and noble gases. In the present embodiment, an example in which air is filled in the pressure chamber 26 will be described. Additionally, the pressure chamber 26 is also a force applying part that applies a force to the striking part 12 downward (one of them) in the vertical direction (first direction) M1.

[0124] The striking part 12 is arranged from the inside to the outside of the housing 11. The striking part 12 has a piston part 28 and a driving blade 29. As an example, the driving blade 29 is made of metal, non-ferrous metal, or steel. The piston part 28 and the driving blade 29 are provided as independent components, and the piston part 28 is connected to the driving blade 29.

[0125] The piston part 28 can operate in the cylinder 27 in the direction along the center line A1. Specifically, the piston part 28 can move vertically (first direction) M1 inside the cylinder 27, and in cooperation with the accumulator vessel 18 and the cylinder 27, demarcate the pressure chamber 26 inside the accumulator vessel 18 and the cylinder 27. And the piston part 28 moves downward (one of them) in the vertical direction (first direction) M1 by the pressure of the compressed air in the pressure chamber 26, thereby striking the nail (fastening member) 78. That is, the striking part 12 including the piston part 28 and the driving blade 29 moves downward (one of them) in the vertical direction (first direction) M1 by the pressure of the compressed air in the pressure chamber 26, thereby striking the nail (fastening member) 78.

[0126] In addition, an annular sealing member is installed on the outer peripheral surface of the piston part 28 facing the cylinder 27. The sealing member abuts against the inner wall 27a of the cylinder 27, thereby suppressing air leakage inside the cylinder 27. The sealing member installed on the piston part 28 will be described in detail later.

[0127] Moreover, the nose part 13 included in the nailer 10 is arranged throughout the inside and outside of the cylinder housing 19. The nose part 13 has a buffer support part 31, a shooting part 32, and a cylindrical part 33. The buffer support part 31 is cylindrical. And a buffer 35 is arranged inside the buffer support part 31. The buffer 35 can be made of synthetic rubber or silicone rubber. The buffer 35 has a guide hole 36. The center line A1 passes through the guide hole 36. The driving blade 29 is arranged in the guide hole 31a of the buffer support part 31 and the guide hole 36.

[0128] The striking part 12 can operate in the nailing direction D1 and the return direction D2 along the center line A1. The nailing direction D1 and the return direction D2 are opposite to each other. The nailing direction D1 is the direction in which the piston part 28 approaches the buffer 35. The return direction D2 is the direction in which the piston part 28 moves away from the buffer 35. The striking part 12 is always urged in the nailing direction D1 by the gas pressure in the pressure chamber 26. The operation of the striking part 12 in the nailing direction D1 can be defined as descending. The operation of the striking part 12 in the return direction D2 can be defined as ascending. The nailing direction D1 is the same as the lower (one) side of the up-down direction (first direction) M1. The return direction D2 is the same as the upper (other) side of the up-down direction (first direction) M1.

[0129] Moreover, the ejection part 32 is connected to the buffer support part 31 and protrudes from the buffer support part 31 in the direction along the center line A1. The ejection part 32 has an ejection passage 37 which is provided along the center line A1. The driving blade 29 can operate in the ejection passage 37 in the direction along the center line A1.

[0130] Moreover, an electric motor 15 is arranged in the motor housing 21. The electric motor 15 has a rotor 39 and a stator 40. The stator 40 is installed in the motor housing 21. The rotor 39 is rotatably supported by the motor housing 21 via a bearing 38. The electric motor 15 is, for example, a brushless motor. When a voltage is applied to the electric motor 15, the motor shaft 47 rotates together with the rotor 39 about the center line A2. As Figure 2 shown, in the left-right direction R1, the center line A2 is in a position offset relative to the center line A1.

[0131] Furthermore, a reduction mechanism 45 is provided in the motor housing 21. The reduction mechanism 45 includes a plurality of planetary gear mechanisms. And, in the cylindrical part 33, a rotating shaft 46 connected to the motor shaft 47 is provided. The rotating shaft 46 and the reduction mechanism 45 are concentrically arranged about the center line A2. The reduction mechanism 45 is arranged on the power transmission path from the electric motor 15 to the rotating shaft 46 and is a mechanism that reduces the rotation of the rotor 39 of the electric motor 15 and transmits it to the winding mechanism 17.

[0132] The winding mechanism 17 is a mechanism that converts the rotational force of the rotating shaft 46 into a force that urges the striking part 12 in the return direction D2. As Figure 2As shown, the hoisting mechanism 17 includes a driving blade 29, a plurality of racks 29a provided on the driving blade 29, a pin wheel 50 serving as a rotating part, and a plurality of needle rollers 50a provided on the pin wheel 50. When the pin wheel 50 rotates in the rotation direction E1 by the driving force of the electric motor 15, the plurality of needle rollers 50a of the pin wheel 50 are sequentially engaged with the plurality of racks 29a of the driving blade 29, and the striking part 12 including the driving blade 29 is pushed upward (return direction D2). In addition, a position detection switch 72 for detecting the position of the driving blade 29 in the vertical direction (first direction) M1 is provided in the ejection part 32.

[0133] Moreover, as Figure 1 shown, a trigger 75 and a trigger switch 71 are provided in the nail gun 10. The trigger 75 and the trigger switch 71 are provided on the handle 20. The trigger switch 71 detects the presence or absence of an operating force applied to the trigger 75 and outputs a signal corresponding to the detection result.

[0134] The power supply unit 14 has a housing case 76 and a battery housed in the housing case 76. The battery has a plurality of battery cells. These battery cells are rechargeable and dischargeable secondary batteries, and the battery cells can arbitrarily use known battery cells such as lithium-ion batteries, nickel-metal hydride batteries, lithium-ion polymer batteries, and nickel-cadmium batteries.

[0135] The electric motor 15 operates by the power supplied from the battery in the fitting part 22 assembled to the housing 11. Moreover, a control unit 73 is housed inside the fitting part 22. The control unit 73 includes a microcomputer including a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), etc., and controls the electric motor 15. Specifically, the control unit 73 changes the duty ratio of the motor current supplied to the electric motor 15 according to the control mode. That is, the control unit 73 performs pulse width modulation (PWM) control on the electric motor 15.

[0136] Moreover, as Figure 2 shown, a magazine 77 is provided in the nail gun 10. The magazine 77 is supported by the ejection part 32 and the fitting part 22. Nails (fasteners) 78 are loaded in the magazine 77. The magazine 77 has a feeder that sends the nails 78 in the magazine 77 to the ejection passage 37. That is, the feeder moves the nails 78 in the magazine 77 toward Figure 1The front side of the front-rear direction N1 shown moves forward. In addition, the injection part 32 is made of metal or synthetic resin. A push rod 79 is installed on the injection part 32. The push rod 79 can operate within a specified range in the direction along the center line A1 relative to the injection part 32. An elastic member (not shown) that applies a force to the push rod 79 in the direction along the center line A1 is provided. As an example, the elastic member is a metal spring that applies a force to the push rod 79 in the direction away from the buffer support part 31.

[0137] The push rod 79 can be switched between ON and OFF by being pressed by an operator against the object material 30. When the push rod 79 is pressed by the object material 30 and moves upward against the force applied by the spring, a signal is output. Moreover, when the operator operates the trigger 75, the trigger switch 71 built into the handle 20 operates, and a signal for the nailing operation is output.

[0138] When the control unit 73 inputs both the signal generated by the operation of the push rod 79 and the signal generated by the operation of the trigger 75, it supplies motor current to the electric motor 15 to operate the electric motor 15. As a result, the pinwheel 50 is rotationally driven, the driving blade 29 is pushed upward, and the piston part 28 moves from the bottom dead center to the top dead center. And the driving blade 29 provided on the piston part 28 is released from the engagement with the pinwheel 50 at the top dead center. Due to the release of the driving blade 29 and the pressure of the air from the pressure chamber 26, the striking part 12 including the driving blade 29 starts to descend and moves from the top dead center toward the bottom dead center. That is, the striking part 12 including the piston part 28 and the driving blade 29 makes a reciprocation between the bottom dead center and the top dead center. Along with this, the nail 78 is struck by the driving blade 29, and the nail 78 is driven in.

[0139] Next, the sealing member provided on the piston part 28 of the nailer 10 will be described. As Figure 3 shown, the piston part 28 includes a base member 28a having a side wall 28b facing the inner wall 27a of the cylinder 27. Further, the piston part 28 has: a first sealing member installed on the base member 28a so as to be interposed between the side wall 28b and the inner wall 27a; and a second sealing member installed on the base member 28a so as to be interposed between the side wall 28b and the inner wall 27a and arranged at a different position in the vertical direction (first direction) M1 with respect to the first sealing member.

[0140] In this embodiment, an X-ring 41 is taken as an example of a first sealing member, and an O-ring 42 is taken as an example of a second sealing member for explanation. That is, the X-ring 41 and the O-ring 42 are mounted on the side wall 28b of the base member 28a of the piston portion 28 as sealing members for the cylinder 27. In addition, a slide ring 43 and a slide ring 44 are mounted on the side wall 28b of the base member 28a of the piston portion 28 for the purpose of suppressing the tilt of the piston portion 28 during sliding.

[0141] like Figures 4 to 7 As shown in FIG. 4 , the X-ring 41 is an elastic member having an X-shaped cross section. Figure 8 As shown, the O-ring 42 is an annular elastic member whose cross-sectional shape is formed into an O-shape.

[0142] X-ring 41 Figure 7 The cross-sectional view of the cross section parallel to the vertical direction (first direction) M1 shown in FIG. 1 includes a circular base (first base) 41a and a base 41a which is vertically arranged from the circular base 41a. Figure 3 The lip portions 41b and 41c contact the cylinder 27. That is, the X-shaped ring 41 has a cross-sectional shape as described below, that is, a circular base portion 41a is arranged in the central portion of the X-shaped cross-section, and has four lips 41b and 41c erected in a manner protruding from the circular base portion 41a in four directions. In detail, the X-shaped ring 41 includes two lips 41b protruding obliquely from the circular base portion 41a in the upper direction of the up-down direction (first direction) M1 and two lips 41c protruding obliquely from the circular base portion 41a in the lower direction of the up-down direction (first direction) M1.

[0143] On the other hand, the O-ring 42 is Figure 8 In the cross-sectional view of the section parallel to the vertical direction (first direction) M1 shown, the O-ring 42 has a circular base (second base) 42a and does not have a lip portion erected from the base 42a. That is, the O-ring 42 has a cross-sectional shape having only the circular base 42a and no lip portion protruding from the circular base 42a.

[0144] And, if Figure 3 As shown, in the side wall 28b of the base member 28a of the piston portion 28, an X-ring 41 is installed in the groove portion 28c provided on the upper side of the side wall 28b in the up-down direction (first direction) M1, and on the other hand, an O-ring 42 is installed in the groove portion 28d provided on the lower side of the side wall 28b in the up-down direction (first direction) M1.

[0145] In other words, the X-ring 41 is installed in the side wall 28b of the base member 28a of the piston portion 28 closer to the pressure chamber 26 (see FIG. 24 ) than the O-ring 42. Figure 1) On the other hand, the O-ring 42 is installed at a position farther from the pressure chamber 26 than the X-ring 41.

[0146] In addition, the abutting force of the X-ring 41 against the cylinder 27 is greater than that of the O-ring 42 against the cylinder 27. In other words, the X-ring 41 abuts against the cylinder 27 with a greater pressure than the O-ring 42. For example, the interference amount of the X-ring 41 relative to the cylinder 27 is greater than that of the O-ring 42 relative to the cylinder 27.

[0147] Here, the interference amounts of the respective sealing members will be described. First, Figure 9 is used to describe the interference amount of the O-ring 42. The interference amount of the O-ring 42 is expressed as an interference rate by the following formula. Interference rate = (W1 - H1) / W1... Formula (1). At this time, W1 = the wire diameter of the O-ring 42, and H1 is the height (depth) measured from the bottom surface 28e of the groove portion 28d. Among them, for the wire diameter W1 of the O-ring 42, the volume (deformed volume) when the inner diameter of the O-ring 42 is expanded and the volume (undeformed volume) before the inner diameter of the O-ring 42 is expanded are calculated according to the following formulas (2) and (3). Undeformed volume: 2 × n 2 × W 2 (inner diameter of the O-ring + W)... Formula (2), where W is the wire diameter of the O-ring 42 before deformation, Deformed volume: 2 × n 2 × Z 2 (inner diameter of the piston + Z)... Formula (3), where Z is the wire diameter of the O-ring 42 after deformation.

[0148] According to Formula (2) = Formula (3), the ratio of the wire diameter Z after deformation to the wire diameter W before deformation is obtained, and the actual wire diameter of the O-ring 42 before deformation is multiplied by the ratio, whereby the wire diameter W1 of the O-ring 42 can be obtained.

[0149] For example, let the actual wire diameter of the O-ring 42 before deformation be 3.5 mm, and let the height (depth) H1 of the groove portion 28d be 3.225 mm. Here, the inner diameter of the O-ring and the inner diameter of the piston are predetermined specified values. At this time, according to Formula (2) = Formula (3), the ratio of the wire diameter Z after deformation to the wire diameter W before deformation is obtained, and the actual wire diameter of the O-ring 42 before deformation is multiplied by the ratio. Thus, the wire diameter W1 of the O-ring 42 = 3.382. Therefore, according to Formula (1), the interference rate of the O-ring 42 is calculated to be 4.64.

[0150] For the X-ring 41, the interference rate can also be calculated in the same way as for the O-ring 42. For example, the actual wire diameter of the X-ring 41 before deformation is set to 3.5 mm, and the height (depth) H1 of the groove portion 28c is set to 3.225 mm. Here, the inner diameter of the X-ring and the inner diameter of the piston are predetermined specified values. At this time, according to equation (2) = equation (3), the ratio of the wire diameter Z after deformation to the wire diameter W before deformation is obtained, and the size of the actual wire diameter of the X-ring 41 before deformation is multiplied by the ratio. Thus, the wire diameter W1 of the X-ring 41 = 3.489. Therefore, according to equation (1), the interference rate of the X-ring 41 is calculated to be 7.57.

[0151] That is, the interference rate of the X-ring 41 > the interference rate of the O-ring 42, so it can be known that the interference amount of the X-ring 41 is greater than the interference amount of the O-ring 42.

[0152] As described above, by making the interference amount of the X-ring 41 greater than the interference amount of the O-ring 42, the contact force of the X-ring 41 against the cylinder 27 can be made greater than that of the O-ring 42. Thus, it is possible to make Figure 3 the surface pressure on the sealing surface 41d of the X-ring 41 in contact with the cylinder 27 greater than the surface pressure on the sealing surface 42b of the O-ring 42 in contact with the cylinder 27 as shown. As a result, the sealing performance of the X-ring 41 at low temperatures can be improved, and thus the occurrence of air leakage at low temperatures can be suppressed. However, if only the X-ring 41 is provided, there is a concern about oil film breakage at normal temperature.

[0153] Therefore, in the nail gun 10 of the present embodiment, in addition to the X-ring 41, an O-ring 42 is further installed on the piston portion 28.

[0154] The O-ring 42 is installed with an interference amount smaller than that of the X-ring 41. If the interference amount is small, the surface pressure of the sealing surface 42b is smaller than the surface pressure of the sealing surface 41d of the X-ring 41. Therefore, the scraping out of the lubricant can be suppressed. Moreover, the O-ring 42 acts as a stopper to prevent the lubricant scraped out downward by the X-ring 41 from being scraped out to a position lower than the O-ring 42, and keeps the lubricant between the X-ring 41 and the O-ring 42. Thus, the occurrence of oil film breakage at normal temperature can be suppressed, and the sealing performance can be improved through the oil film even at normal temperature. As a result, the O-ring 42 can suppress air leakage caused by a decrease in sealing performance due to oil film breakage at normal temperature.

[0155] That is, in the nail gun 10, the X-ring 41 with a large interference amount and the O-ring 42 with a small interference amount in comparison with each other are combined and installed on the piston portion 28. Thus, the sealing performance at low temperatures can be improved by the X-ring 41, and the oil film breakage at normal temperature can be suppressed by the O-ring 42, thereby ensuring the sealing performance. Thus, the O-ring 42 can suppress air leakage at normal temperature.

[0156] In addition, the interference amount of the X-ring 41 in the nailer 10 of the present embodiment is set to be larger than that of the O-ring 42, but smaller than the interference amount of the X-ring of a conventional nailer in which an X-ring monomer is installed on the piston. That is, in the nailer 10 of the present embodiment, both the X-ring 41 and the O-ring 42 are set to have an interference amount smaller than that of the X-ring of a conventional nailer.

[0157] Moreover, the X-ring 41 preferably includes a material having a higher mechanical strength or durability than the O-ring 42. As the material forming the X-ring 41, for example, hydrogenated nitrile rubber (HNBR) can be cited. Hydrogenated nitrile rubber has both high pressure resistance and high mechanical strength, and is a suitable material for high-pressure parts or sliding parts that require relative wear resistance. By the X-ring 41 including a material having a higher mechanical strength or durability than the O-ring 42, the strength of the X-ring 41 can be ensured, and thus the sealing performance at normal temperature and low temperature can be improved for a long time.

[0158] On the other hand, the O-ring 42 preferably includes a material having a higher cold resistance than the X-ring 41. As the material forming the O-ring 42, for example, ethylene propylene diene monomer (EPDM) can be cited. Ethylene propylene diene monomer has a low embrittlement temperature, and thus can maintain its strength even at low temperatures. By the O-ring 42 including a material having a higher cold resistance than the X-ring 41, the sealing performance at low temperature can be further improved. In addition, the material forming the O-ring 42 can also be nitrile butadiene rubber (NBR). Nitrile butadiene rubber generally has a lower cold resistance than ethylene propylene diene monomer, but by adjusting the ratio of the materials constituting nitrile butadiene rubber to increase the hardness, the cold resistance can also be sufficiently improved.

[0159] Here, the shape of the X-ring 41 will be described in detail. As Figure 7 shown, in a cross-section of the X-ring 41, it includes a circular base (first base) 41a and four lips 41b, 41c protruding from the circular base 41a. The protruding directions G1 of the two lips 41b protruding toward the upper side among the four lips 41b, 41c from the base 41a are in a direction inclined with respect to the radial direction J1 of the cylinder 27 (refer to Figure 1 ) in such a manner that it is from the outside of the lip 41b in the radial direction J1 toward the upper (other) side in the vertical direction (first direction) M1. That is, the protruding directions G1 of the two lips 41b each protruding from the base 41a are different obliquely upward directions. Similarly, the protruding directions of the two lips 41c each protruding from the base 41a are different obliquely downward directions.

[0160] Moreover, in a cross-section of the X-ring 41, the thickness T1 of the lip portion 41b in the orthogonal direction K1 orthogonal to the protruding direction G1 in which the lip portion 41b protrudes from the base portion 41a is smaller than the minor diameter P1 of the base portion 41a. As an example, T1 = 0.972 mm and P1 = 2.8 mm. Further, in a cross-section of the X-ring 41, the length L1 of the lip portion 41b in the protruding direction G1 in which the lip portion 41b protrudes from the base portion 41a is equal to the thickness T1 of the lip portion 41b in the orthogonal direction K1 orthogonal to the protruding direction G1. Specifically, the length L1 of the lip portion 41b is in the range of plus or minus 20% of the thickness T1 of the lip portion 41b or more. As an example, L1 = 0.872 mm.

[0161] Next, the arrangement in the vertical direction (first direction) M1 of the X-ring 41 and the O-ring 42 will be described. As Figure 3 shown, the X-ring 41 is installed in the groove portion 28c on the upper side in the vertical direction (first direction) M1 than the O-ring 42, while the O-ring 42 is installed in the groove portion 28d on the lower side in the vertical direction (first direction) M1 than the X-ring 41. Here, as Figure 1 shown, in the stapler 10, a pressure chamber 26 is provided above the cylinder 27. Therefore, the X-ring 41 is installed in the piston portion 28 at a position closer to the pressure chamber 26 than the O-ring 42, while the O-ring 42 is installed at a position farther from the pressure chamber 26 than the X-ring 41. And, by the pressure of the air from the pressure chamber 26, the piston portion 28 is pushed downward. At this time, a large pressure brought by the air from the pressure chamber 26 is applied to the sealing member arranged on the upper side in the piston portion 28.

[0162] Therefore, in the stapler 10 of the present embodiment, in the side wall 28b of the base member 28a of the piston portion 28, the X-ring 41 is arranged on the side closer to the pressure chamber 26 (top dead center side), and the O-ring 42 is arranged on the side farther from the pressure chamber 26 (bottom dead center side). Thereby, by arranging the X-ring 41 on the top dead center side, even for the large pressure brought by the air from the pressure chamber 26, the sealing performance of the piston portion 28 can be ensured.

[0163] That is, in the X-ring 41, there is provided Figure 7Two lips 41b protruding obliquely upward, respectively, as shown. These two lips 41b respectively abut against the inner wall 27a of the cylinder 27 to mainly ensure the sealing property. At this time, when the pressure of the air from the pressure chamber 26 is applied from the upper side to the X-ring 41, the air enters the upper side of the X-ring 41, and the X-ring 41 is flattened downward. At this time, the X-ring 41 deforms in such a way that the front end side of the lip 41b protruding obliquely upward is pressed and widened outward. That is, the two lips 41b deform to abut more strongly against the inner wall 27a of the cylinder 27. As a result, the surface pressure of the X-ring 41 against the inner wall 27a of the cylinder 27 becomes higher, and the sealing property brought by the X-ring 41 can be further improved. That is, by arranging the X-ring 41 on the top dead center side, the surface pressure of the X-ring 41 against the cylinder 27 is further increased, so that the sealing property of the piston portion 28 can be further improved.

[0164] In addition, the X-ring 41 originally has an interference amount larger than that of the O-ring 42, so that the surface pressure is increased. Therefore, by further increasing the surface pressure, the sealing property can be improved especially at low temperatures. As a result, air leakage can be suppressed even at low temperatures. As described above, by arranging the X-ring 41 on the top dead center side, the surface pressure can be further increased, so that the sealing property at low temperatures can be improved.

[0165] On the other hand, in this case, there is a concern about the oil film breakage of the lubricant at normal temperature. However, in the stapler 10 of the present embodiment, the O-ring 42 is arranged on the bottom dead center side. The surface pressure on the bottom dead center side does not increase as much as that of the X-ring 41 under the large pressure brought by the air from the pressure chamber 26. Furthermore, the O-ring 42 also sets the interference amount smaller than that of the X-ring 41, so the surface pressure of the O-ring 42 is originally small. Therefore, it is difficult for the oil film breakage to occur in the O-ring 42. Furthermore, in terms of shape, the O-ring 42 is a circular shape without lips, so the contact surface with the cylinder 27 is also small, and it is also difficult for the oil film breakage to occur compared with the X-ring 41. That is, in the O-ring 42 arranged on the bottom dead center side, it is difficult to cause the oil film breakage. Moreover, the O-ring 42 functions as a stopper that prevents the lubricant scraped downward by the X-ring 41 from being scraped out below the O-ring 42, and keeps the lubricant between the X-ring 41 and the O-ring 42. As a result, the oil film breakage at normal temperature can be alleviated, and the sealing property brought by the lubricant (oil film) can be ensured.

[0166] As described above, in the nailer 10 of the present embodiment, a sealing member (X-ring 41) having a high surface pressure at low temperatures is arranged in comparison with each other, and a sealing member (O-ring 42) having a low surface pressure at normal temperatures is arranged. Thus, both oil film breakage can be suppressed and airtightness can be ensured. As a result, the occurrence of air leakage can be suppressed, and the frequency with which an operator interrupts the nailing operation to replenish air can be reduced. That is, air leakage of the nailer 10 can be suppressed, and the nailer 10 can be used for a long time. As a result, the convenience of the nailer 10 can be improved.

[0167] Next, a modification of the present embodiment will be described. Figure 10 In the first modification shown, a V-ring 48 is used as the first sealing member in place of the X-ring 41 on the top dead center side of the side wall 28b of the base member 28a of the piston portion 28, and an O-ring 42 is installed on the bottom dead center side.

[0168] As Figure 11 shown, in a cross-section of the V-ring 48, it includes a circular base portion (first base portion) 48a disposed at the center of the V-shaped cross-section and two lip portions 48b protruding in two directions from the circular base portion 48a. The two lip portions 48b protrude upward. Specifically, the protruding direction G1 in which the two lip portions 48b protrude from the base portion 48a is a direction inclined with respect to the radial direction J1 of the cylinder 27 (see Figure 1 ) such that the outer side of the lip portion 48b in the radial direction J1 faces the upper (other) side in the vertical direction (first direction) M1. That is, the protruding directions G1 in which the two lip portions 48b protrude from the base portion 48a are different obliquely upward directions.

[0169] Moreover, in a cross-section of the V-ring 48, the thickness T1 of the lip portion 48b in the orthogonal direction K1 orthogonal to the protruding direction G1 in which the lip portion 48b protrudes from the base portion 48a is smaller than the minor diameter P1 of the base portion 48a. Further, in a cross-section of the V-ring 48, the length L1 of the lip portion 48b in the protruding direction G1 in which the lip portion 48b protrudes from the base portion 48a is equal to the thickness T1 of the lip portion 48b in the orthogonal direction K1 orthogonal to the protruding direction G1. Specifically, the length L1 of the lip portion 48b is in the range of plus or minus 20% of the thickness T1 of the lip portion 48b or more.

[0170] As Figure 10As shown, the V-ring 48 is disposed on the top dead center side of the piston portion 28 to form a sealing surface 48c at the contact portion with the inner wall 27a of the cylinder 27. As a result, the surface pressure can be further increased, and thus the sealing performance at low temperatures can be improved. Further, by disposing the O-ring 42 on the bottom dead center side of the piston portion 28, the oil film breakage at normal temperature can be reduced, and the sealing performance provided by the lubricant (oil film) can be ensured. That is, by disposing the sealing member (O-ring 42) with the lowest surface pressure at normal temperature, both the oil film breakage can be suppressed and the sealing performance can be ensured. As a result, the occurrence of air leakage can be suppressed, and the frequency of the operator interrupting the nailing operation to replenish air can be reduced. That is, the air leakage of the nailer 10 can be suppressed, and the nailer 10 can be used for a long time. As a result, even when the V-ring 48 is used instead of the X-ring 41, the convenience of the nailer 10 can be improved.

[0171] Moreover, Figure 12 In the second modification shown, an X-ring 41 is disposed as the first sealing member on the top dead center side of the side wall 28b of the base member 28a of the piston portion 28, and a D-ring 49 is used as the second sealing member instead of the O-ring 42 on the bottom dead center side. By disposing the X-ring 41 on the top dead center side of the piston portion 28, the surface pressure on the top dead center side can be further increased, and thus the sealing performance at low temperatures can be improved. Further, by disposing the D-ring 49 on the bottom dead center side of the piston portion 28, similar to the case of the O-ring 42, the oil film breakage at normal temperature can be reduced, and the sealing performance provided by the lubricant (oil film) can be ensured.

[0172] Similar to the O-ring 42, the D-ring 49 has only a circular base portion (second base portion) 49a and does not have a lip portion. Therefore, in the sealing surface 49b at the contact portion of the D-ring 49 with the cylinder 27, the surface pressure can be reduced at normal temperature, and thus the oil film breakage of the lubricant can be suppressed. That is, by disposing the X-ring 41 on the top dead center side and the D-ring 49 on the bottom dead center side, both the oil film breakage can be suppressed and the sealing performance can be ensured. As a result, the occurrence of air leakage can be suppressed, and the frequency of the operator interrupting the nailing operation to replenish air can be reduced. That is, the air leakage of the nailer 10 can be suppressed, and the nailer 10 can be used for a long time. As a result, even when the D-ring 49 is used instead of the O-ring 42, the convenience of the nailer 10 can be improved.

[0173] The present utility model is not limited to the described embodiments, and various changes can be made without departing from its gist. For example, in the described embodiments, as the second sealing member, a sealing member with a circular or D-shaped cross-sectional shape is illustrated, but as the second sealing member, its cross-sectional shape can also be a quadrilateral such as a square or an ellipse. Moreover, the following structure can also be adopted: the positions of the X-ring 41 and the O-ring 42 are set to be opposite to those in the described embodiments, and the O-ring 42 is arranged closer to the top dead center side than the X-ring 41. At this time, compared with the described embodiments, although the effect of improving the sealing performance of the X-ring 41 by the pressure of the air from the pressure chamber 26 is low, the effect of retaining the lubricant between the X-ring 41 and the O-ring 42 remains unchanged, and the air leakage caused by oil film breakage can be reduced. Moreover, in this case, by making the interference amount of the X-ring 41 higher than that in the described embodiments, the sealing performance of the X-ring 41 can also be improved, thereby suppressing the air leakage at low temperatures. The O-ring 42 can also have an interference amount similar to that of the X-ring 41. In this case, by retaining the lubricant between the X-ring 41 and the O-ring 42, the oil film breakage between the X-ring 41 and the O-ring 42 is also reduced, and the sealing performance is improved due to the increase in the interference amount of the O-ring 42, thereby suppressing the air leakage.

Claims

1. A working machine, characterized in that: include: A hollow shell portion including a cylinder, wherein the cylinder is in a cylindrical shape extending in a first direction and has an inner wall; as well as The piston part is movable in the first direction inside the cylinder, cooperates with the shell part to define a pressure chamber inside the shell part, and moves to one side of the first direction by the pressure of the gas inside the pressure chamber, thereby hitting the fixing member. The piston portion comprises: a base member having a side wall facing the inner wall of the cylinder; a first sealing member installed on the base member in a manner interposed between the side wall and the inner wall; and a second sealing member installed on the base member in a manner interposed between the side wall and the inner wall and arranged at a different position in the first direction relative to the first sealing member. The first sealing member includes a first base portion and a lip portion erected from the first base portion and in contact with the cylinder in a cross-sectional view taken along a plane parallel to the first direction. The second sealing member has a second base portion in the cross-sectional view and does not have a lip portion erected from the second base portion.

2. The working machine according to claim 1, characterized in that: An abutment force of the first sealing member with respect to the cylinder is greater than an abutment force of the second sealing member with respect to the cylinder.

3. The working machine according to claim 2, characterized in that: An interference amount of the first sealing member relative to the cylinder is greater than an interference amount of the second sealing member relative to the cylinder.

4. The working machine according to claim 1, characterized in that: The first sealing member is arranged on the other side in the first direction relative to the second sealing member.

5. The working machine according to claim 1, characterized in that: The first sealing member has higher mechanical strength than the second sealing member.

6. The working machine according to claim 1, characterized in that: The second sealing member has higher cold resistance than the first sealing member.

7. The working machine according to claim 1, characterized in that: In the cross-sectional view of the first sealing member, the protruding direction of the lip portion of the first sealing member from the first base portion is inclined with respect to the radial direction so that the outer side of the lip portion in the radial direction of the cylinder faces the other side in the first direction.

8. The working machine according to claim 1, characterized in that: In the cross-sectional view of the first sealing member, a thickness of the lip portion in a direction orthogonal to a protruding direction of the lip portion of the first sealing member from the first base portion is smaller than a minor diameter of the first base portion.

9. The working machine according to claim 1, characterized in that: In the cross-sectional view of the first sealing member, a length of the lip portion of the first sealing member in a protruding direction in which the lip portion protrudes from the first base portion is equal to a thickness of the lip portion in a direction orthogonal to the protruding direction.

10. A working machine, characterized in that: include: A hollow shell portion including a cylinder, wherein the cylinder is in a cylindrical shape extending in a first direction and has an inner wall; as well as The piston part is movable in the first direction inside the cylinder, cooperates with the shell part to define a pressure chamber inside the shell part, and moves to one side of the first direction by the pressure of the gas inside the pressure chamber, thereby hitting the fixing member. The piston portion comprises: a base member having a side wall facing the inner wall of the cylinder; a first sealing member mounted on the base member in a manner interposed between the side wall and the inner wall; and a second sealing member mounted on the base member so as to be interposed between the side wall and the inner wall and arranged on the one side in the first direction relative to the first sealing member, An abutment force of the first sealing member with respect to the cylinder is greater than an abutment force of the second sealing member with respect to the cylinder.

11. The working machine according to claim 10, characterized in that: An interference amount of the first sealing member relative to the cylinder is greater than an interference amount of the second sealing member relative to the cylinder.

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