Work equipment

Abstract

To prevent liquid from being little supplied to a discharge pipe even when an amount of liquid stored in a liquid tank decreases.SOLUTION: A work machine discharges liquid. The work machine comprises a discharge pipe for discharging liquid, and a liquid tank. The liquid tank includes a tank body for storing liquid, a supply port for supplying the liquid to the tank body, a communication hole, a protrusion to be disposed on a top of the tank body when the work machine is placed on a placement surface, a cap to be engaged with the protrusion to close the supply port, and a unidirectional valve attached to the protrusion. When the cap is engaged with the protrusion to close the supply port, the communication hole communicates the inside of the liquid tank with the outside of the work machine. The unidirectional valve is configured to prohibit a flow of fluid heading from the inside of the liquid tank toward the outside of the work machine through the communication hole and to allow a flow of the fluid heading from the outside of the work machine toward the inside of the liquid tank through the communication hole.SELECTED DRAWING: Figure 15

Description

Technical Field

[0001] The technology disclosed in this specification relates to a working machine.

Background Art

[0002] Patent Document 1 discloses a working machine that discharges a liquid. The working machine includes a discharge pipe that discharges the liquid and a liquid tank. The liquid tank has a tank body that stores the liquid and a supply port for supplying the liquid to the tank body. When the working machine is placed on a mounting surface, it includes a protruding portion connected to the upper part of the tank body and a cap that engages with the protruding portion to close the supply port.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above - mentioned working machine, as the working machine operates, the amount of liquid stored in the liquid tank decreases, and the volume of the void in the liquid tank increases. Since the supply port is closed by the cap and it is difficult for air to flow into the liquid tank, when the amount of liquid stored in the liquid tank decreases, the pressure in the void of the liquid tank decreases. As a result, it becomes difficult for the liquid to be supplied toward the discharge pipe. In this specification, a technology is provided that can suppress the difficulty of supplying the liquid toward the discharge pipe even when the amount of liquid stored in the liquid tank decreases.

Means for Solving the Problems

[0005] This specification discloses a work machine for discharging liquid. The work machine comprises a discharge pipe for discharging liquid and a liquid tank. The liquid tank has a tank body for storing liquid, a supply port for supplying liquid to the tank body, and a communication hole, and includes a projection positioned on the top of the tank body when the work machine is placed on a mounting surface, a cap that engages with the projection to close the supply port, and a one-way valve attached to the projection. When the cap is engaged with the projection to close the supply port, the communication hole communicates the inside of the liquid tank with the outside of the work machine. The one-way valve is configured to prohibit the flow of fluid from the inside of the liquid tank to the outside of the work machine through the communication hole, and to allow the flow of fluid from the outside of the work machine to the inside of the liquid tank through the communication hole.

[0006] According to the above configuration, even when the cap is engaged with the protrusion and blocking the supply port, when the one-way valve is opened, the inside of the liquid tank and the outside of the work machine communicate through the communication hole. Even if the amount of liquid stored in the liquid tank decreases, the flow of fluid, such as air, into the liquid tank through the communication hole can suppress a decrease in the pressure of the void inside the liquid tank. This can suppress the difficulty in supplying liquid towards the discharge pipe. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view of the work machine 2 of the embodiment. [Figure 2] This is a right side view of the work machine 2 of the embodiment, when the discharge pipe 10 has been removed from the main unit 4. [Figure 3] This is an exploded perspective view of the work machine 2 of the embodiment. [Figure 4] This is a perspective view of the work machine 2 of the embodiment when the cover portion 34 is open. [Figure 5] This is a top view of the work machine 2 of the embodiment. [Figure 6] This is a rear view of the work machine 2 of the embodiment, with the rear main body housing 28 removed. [Figure 7]This is an exploded perspective view of the fan unit 18 and control unit 20 of the embodiment. [Figure 8] This is a perspective view of the discharge pipe 10 in the embodiment. [Figure 9] This is an exploded perspective view of the liquid tank 24 in the embodiment. [Figure 10] This is a horizontal cross-sectional view of the implement 2 of the embodiment. [Figure 11] This is a perspective view of the liquid tank 24, discharge tube 91, and supply line 113 of the embodiment. [Figure 12] This is a horizontal cross-sectional view of the liquid tank 24 of the embodiment near the protruding portion 92. [Figure 13] This is a longitudinal cross-sectional view of the work machine 2 of the embodiment. [Figure 14] This is an enlarged cross-sectional view of the liquid tank 24 of the embodiment when the one-way valve 144 is closed. [Figure 15] This is an enlarged cross-sectional view of the liquid tank 24 of the embodiment when the one-way valve 144 is open. [Figure 16] This is a perspective view of the frame unit 6 of the embodiment. [Figure 17] This is a perspective view of the work machine 2 of the embodiment, with the frame unit 6 and harness unit 8 removed from the main body housing 16. [Figure 18] This is an exploded perspective view of the work machine 2 of the embodiment, with the discharge pipe 10 removed from the main unit 4. [Figure 19] This is a rear view of the work machine 2 of the embodiment. [Figure 20] This is a longitudinal cross-sectional view of the vicinity of the lower opposing surface 200 of the work machine 2 in the embodiment. [Figure 21] This is a front view of the work machine 2 of the embodiment. [Figure 22] This is a cross-sectional perspective view of the discharge pipe 10, cylindrical member 250, and liquid nozzle 252 of the embodiment. [Figure 23] This is a perspective view of the liquid nozzle 252 of the embodiment. [Figure 24] This is a cross-sectional view of the second supply pipe 240 and liquid nozzle 252 of the embodiment. [Figure 25]It is an enlarged cross-sectional view near the tip of the liquid nozzle 252 of the embodiment. [Figure 26] It is an enlarged cross-sectional view near the corner 290 of the liquid nozzle 252 of the embodiment. [Figure 27] It is a front view of the liquid nozzle 252 of the modified example as viewed from the front side. [Figure 28] It is an enlarged cross-sectional view near the tip of the liquid nozzle 252 of the modified example.

Modes for Carrying Out the Invention

[0008] Representative and non-limiting specific examples of the present invention will be described in detail below with reference to the drawings. This detailed description is merely intended to show those skilled in the art the details for implementing preferred examples of the present invention, and is not intended to limit the scope of the present invention. Also, the additional features and inventions disclosed can be used separately or together with other features and inventions to provide a further improved working machine.

[0009] Also, the combinations of features and steps disclosed in the following detailed description are not essential for implementing the present invention in the broadest sense, and are described only for the purpose of explaining representative specific examples of the present invention. Furthermore, the various features of the following representative specific examples, as well as the various features described in the claims, do not have to be combined as described in the specific examples or in the order listed when providing additional and useful embodiments of the present invention.

[0010] All features described in this specification and / or the claims are intended to be disclosed individually and independently of each other as limitations on the initial disclosure and the specific matters described in the claims, separate from the configurations of the features described in the examples and / or the claims. Furthermore, all descriptions of numerical ranges and groups or populations are made with the intention of disclosing intermediate configurations as limitations on the initial disclosure and the specific matters described in the claims.

[0011] In one or more embodiments, the projection may include a side wall defining a supply port. The communication hole may be located in the side wall.

[0012] According to the above configuration, it is possible to suppress the difficulty in supplying liquid towards the discharge pipe without complicating the structure of the protruding part.

[0013] In one or more embodiments, the cap may include a spirally extending engaging rail. The side wall may comprise a first side having an engaging rail that engages with the engaging rail, the engaging rail extending along the circumferential direction of the outer surface of the side wall, and a second side not having an engaging rail formed on the circumferential direction of the outer surface of the side wall. A communication hole may be located on the second side.

[0014] According to the above configuration, the side wall is distinguished into an area where the engaged rail is located and an area where the communication hole is located. The engagement between the engaged rail and the engaging rail makes it possible to prevent the inside of the liquid tank and the outside of the work machine from becoming difficult to communicate through the communication hole.

[0015] In one or more embodiments, the second side may be recessed radially inward compared to the first side.

[0016] According to the above configuration, even when the cap engages with the protrusion, the outer surface of the second side does not come into contact with the cap. This prevents the inside of the liquid tank and the outside of the work machine from becoming difficult to communicate through the communication hole.

[0017] In one or more embodiments, the one-way valve is located inside the liquid tank and may include a valve section capable of blocking a communication hole.

[0018] According to the above configuration, it is possible to prevent foreign matter, such as sand, from adhering to the valve part from being outside the liquid tank. This prevents the one-way valve from becoming difficult to open and close due to sand or other foreign matter.

[0019] In one or more embodiments, the liquid tank may include a filter unit that can be attached to the supply port of the protrusion and captures foreign matter contained in the liquid when the liquid is supplied to the tank body. The valve may be located between the filter unit and the side wall.

[0020] According to the above configuration, it is possible to suppress the adhesion of foreign matter contained in the liquid, such as sand, to the valve. This prevents the one-way valve from becoming difficult to open and close due to sand or other foreign matter.

[0021] In one or more embodiments, when the cap engages with the projection and blocks the supply port, the communication hole may be covered by the cap.

[0022] According to the above configuration, it is possible to prevent sand or other materials outside the liquid tank from blocking the communication holes.

[0023] In one or more embodiments, when the cap engages with the projection to close the supply port, a communication space may be defined between the cap and the projection. The communication hole may connect the communication space to the inside of the liquid tank. At its lower end, the communication space may connect to the outside of the work machine.

[0024] With the above configuration, sand and other debris outside the liquid tank are less likely to enter the communication space. This further reduces the likelihood of sand and other debris blocking the communication holes.

[0025] In one or more embodiments, the one-way valve may be an umbrella valve.

[0026] With the above configuration, the one-way valve can be opened with relatively little force.

[0027] (Examples) As shown in Figure 1, the implement 2 is a backpack-type implement. The implement 2 is configured to discharge (spray) a liquid. The implement 2 is, for example, a mist blower. The liquid is, for example, a chemical solution or water. The liquid is stored in a liquid tank 24, which will be described later. The implement 2 comprises a main unit 4, a frame unit 6, a harness unit 8, a discharge pipe 10, and a handle unit 12. The frame unit 6 is attached to the main unit 4. The harness unit 8 is attached to the main unit 4 directly and / or indirectly. The discharge pipe 10 is attached to the lower right side of the main unit 4. The handle unit 12 is attached to the discharge pipe 10. The user, wearing the harness unit 8 and carrying the implement 2 on their back, grasps the handle unit 12 and manipulates the discharge pipe 10 to spray the liquid from the discharge pipe 10. As shown in Figure 2, the main unit 4 has a facing surface 4a that faces the user's back when the work machine 2 is carried on the user's back. Hereinafter, when the work machine 2 is placed on a mounting surface P such as the ground, the direction perpendicular to the facing surface 4a will be called the front-rear direction, the direction perpendicular to the mounting surface P will be called the up-down direction, and the direction perpendicular to the front-rear direction and the up-down direction will be called the left-right direction.

[0028] As shown in Figure 3, the main unit 4 comprises a main housing 16, a fan unit 18, a control unit 20, a battery unit 22, and a liquid tank 24. The main housing 16 supports the fan unit 18, the battery unit 22, and the liquid tank 24. The main housing 16 comprises a front main housing 26 and a rear main housing 28. As shown in Figure 2, the front main housing 26 has a facing surface 30 that faces the user's back when the work machine 2 is carried on the user's back. The facing surface 30 constitutes part of the facing surface 4a of the main unit 4.

[0029] As shown in Figure 4, the rear main body housing 28 comprises a main body portion 32 and a cover portion 34. The main body portion 32 is fixed to the front main body housing 26 with screws (not shown). The cover portion 34 is rotatably attached to the front main body housing 26. The cover portion 34 rotates around a pivot axis that extends in the left-right direction. The pivot axis of the cover portion 34 is located above the battery unit 22. The cover portion 34 is located behind the battery unit 22.

[0030] As shown in Figures 3 and 4, a first internal space 36 and a second internal space 38 are defined between the front main housing 26 and the rear main housing 28. The fan unit 18 and the control unit 20 are located in the first internal space 36. A cover 40 is attached near the lower left side of the main housing 16, and the first internal space 36 communicates with the outside of the work machine 2 through the air intake port 40a of the cover 40. The second internal space 38 is located above the first internal space 36. The second internal space 38 is separated from the first internal space 36. The battery unit 22 is located in the second internal space 38. For this reason, the battery pack BP, which will be described later, is located in the second internal space 38. By opening the cover portion 34 upwards, the second internal space 38 communicates with the outside of the work machine 2.

[0031] The fan unit 18, the battery unit 22, and the liquid tank 24 are arranged side by side in the vertical direction. The battery unit 22 is positioned above the fan unit 18, and the liquid tank 24 is positioned above the battery unit 22. As shown in Figure 5, when the work machine 2 is placed on the mounting surface P (see Figure 2) and viewed from above, at least 50% of the area of ​​the liquid tank 24 overlaps with the fan unit 18 and the battery unit 22, respectively. In Figure 5, the outline of the fan unit 18 is shown by a dashed line, and the outline of the battery unit 22 is shown by a dotted line. Furthermore, at least 50% of the area of ​​the fan unit 18 overlaps with the battery unit 22 and the liquid tank 24, respectively. In addition, at least 50% of the area of ​​the battery unit 22 overlaps with the fan unit 18 and the liquid tank 24, respectively.

[0032] Next, the center of gravity will be described with reference to Figures 2 and 6. The center of gravity of the fan unit 18 is at center of gravity position G1. When the two battery packs BP are placed in the second internal space 38, the center of gravity of the battery unit 22 is at center of gravity position G2, and when the two battery packs BP are not placed in the second internal space 38, the center of gravity of the battery unit 22 is at center of gravity position G3. Furthermore, when the liquid tank 24 is filled to its maximum liquid level, the center of gravity of the liquid tank 24 is at center of gravity position G4, and when the liquid tank 24 is empty, the center of gravity of the liquid tank 24 is at center of gravity position G5. Furthermore, when two battery packs BP are located in the second internal space 38 and the liquid tank 24 is filled to its maximum capacity, the center of gravity of the main unit 4 is at center of gravity position G6. When two battery packs BP are located in the second internal space 38 and the liquid tank 24 is empty, the center of gravity of the main unit 4 is at center of gravity position G7.

[0033] As shown in Figure 2, the center of gravity positions G2 and G3 of the battery unit 22 are approximately the same in the front-rear and up-down directions, respectively. The center of gravity position G4 of the liquid tank 24 is approximately the same as the center of gravity position G5 in the front-rear direction, and is located slightly below the center of gravity position G5 in the up-down direction. The center of gravity position G6 of the main unit 4 is located slightly behind the center of gravity position G7 in the front-rear direction, and is located above the center of gravity position G7 in the up-down direction.

[0034] Regarding the front-to-back direction, the center of gravity G1 of the fan unit 18, the center of gravity G2 and G3 of the battery unit 22, the center of gravity G4 and G5 of the liquid tank 24, and the center of gravity G6 and G7 of the main unit 4 are located in a region that is 1 / 3 of the front-to-back width of the main unit 4 (in this embodiment, a region that is 1 / 6 of the front-to-back width of the main unit 4). In Figure 2, the region that is 1 / 3 of the front-to-back width of the main unit 4 is illustrated by a dashed line. The center of gravity G1 is located near the center CP1 of the main unit 4 in the front-to-back direction. The center of gravity G2, G3, G4, G5, G6, and G7 are located on the opposite side 4a (front side) of the center CP1. The center CP1 is located at the center between the front and rear ends of the main unit 4. In Figure 2, the center CP1 is illustrated by a dashed line.

[0035] As shown in Figure 6, the center of gravity positions G2 and G3 of the battery unit 22 are approximately the same in the left-right direction. The center of gravity positions G4 and G5 of the liquid tank 24 are approximately the same in the left-right direction. The center of gravity position G6 of the main unit 4 is located further away from the discharge pipe 10 (to the left) than the center of gravity position G7 in the left-right direction.

[0036] Regarding the left-right direction, the center of gravity G1 of the fan unit 18, the center of gravity G2 and G3 of the battery unit 22, the center of gravity G4 and G5 of the liquid tank 24, and the center of gravity G6 and G7 of the main unit 4 are located in a region that is 1 / 3 of the width of the main unit 4 in the left-right direction (in this embodiment, a region that is 1 / 6 of the width of the main unit 4 in the left-right direction). In Figure 6, the region that is 1 / 3 of the width of the main unit 4 in the left-right direction is illustrated by a dashed line. The center of gravity G1, G6, and G7 are located on the discharge pipe 10 side (right side) of the center position CP2 of the main unit 4 in the left-right direction. The center of gravity G2, G3, G4, and G5 are located near the center position CP2 of the main unit 4 in the left-right direction. The center position CP2 is located in the center between the right end and the left end of the main unit 4. In Figure 6, the center position CP2 is illustrated by a dashed line.

[0037] As shown in Figure 7, the fan unit 18 comprises a fan 44, an electric motor 46, a motor housing 48, a cover member 50, a cone 52, and a cylindrical member 54. The fan 44 is, for example, an axial flow fan. The shaft 46a of the electric motor 46 is connected to the fan 44. The electric motor 46 rotates the fan 44. The electric motor 46 is, for example, a brushless motor. The motor housing 48 houses the electric motor 46. Multiple rectifier fins 55 are formed on the outer surface of the motor housing 48. The cover member 50 closes the left end opening of the motor housing 48. The cone 52 is connected to the right end of the motor housing 48. The cylindrical member 54 has a substantially cylindrical shape. The cylindrical member 54 houses the fan 44, the electric motor 46, the motor housing 48, and the cover member 50 inside. The inner surface of the cylindrical member 54 is connected to multiple rectifier fins 55. The cylindrical member 54 is supported by the main housing 16 (see Figure 3).

[0038] The control unit 20 is mounted on the upper part of the cylindrical member 54. The control unit 20 includes a control board 56 which has a plurality of switching elements (not shown) and a microcontroller. The control board 56 controls the rotation of the electric motor 46. The control board 56 is housed in a case 57. An opening 54a is formed in the upper part of the cylindrical member 54, and at least a portion of the lower surface of the case 57 closes the opening 54a of the cylindrical member 54. The case 57 is made of, for example, a metal material. The control unit 20 is covered by a cover member 58. The case 57 and the cover member 58 are attached to the cylindrical member 54.

[0039] A discharge pipe 10, as shown in Figure 1, is attached to the cylindrical member 54. The discharge pipe 10 is located on the right side of the main unit 4. The discharge pipe 10 comprises a curved pipe 60 attached to the cylindrical member 54 (see Figure 3), a bellows pipe 62 attached to the curved pipe 60, an intermediate pipe 64 attached to the bellows pipe 62, and a tip pipe 66 attached to the intermediate pipe 64. The bellows pipe 62 is configured to allow adjustment of the orientation of the intermediate pipe 64 and the tip pipe 66. As shown in Figure 8, a dome-shaped diffusion cover 70 is attached to the tip of the tip pipe 66.

[0040] A handle unit 12 is attached to the intermediate pipe 64. The handle unit 12 comprises a gripping portion 72 that is grasped by the user, a trigger 74 attached to the gripping portion 72, and a head portion 76 connected to the gripping portion 72. The user can adjust the orientation of the intermediate pipe 64 and the tip pipe 66 by grasping the gripping portion 72 and moving the handle unit 12. The user can also press the trigger 74 with the fingers of the hand that is grasping the gripping portion 72. When the trigger 74 is pressed, a signal is sent to the control board 56 (see Figure 7).

[0041] As shown in Figure 1, the head unit 76 is equipped with a main power button 78 and an adjustment button 80. The main power button 78 is located on the rear surface of the head unit 76. The main power button 78 accepts user input to switch the work machine 2 on and off. The user operates the main power button 78 with the fingers of the hand gripping the gripping unit 72. When the main power button 78 is operated, a signal is sent to the control board 56 (see Figure 7). The adjustment button 80 is located on the top surface of the head unit 76. The adjustment button 80 accepts user input to adjust the rotation speed of the electric motor 46 (see Figure 7). The user can operate the adjustment button 80 with the fingers of the hand opposite to the hand gripping the gripping unit 72. When the adjustment button 80 is operated, a signal is sent to the control board 56.

[0042] When the work machine 2 is in the ON state, if the user presses the trigger 74, the control board 56 rotates the shaft 46a of the electric motor 46, causing the fan 44 to rotate, as shown in Figure 7. As a result, as shown in Figure 3, air flows from outside the work machine 2 into the first internal space 36 through multiple intake ports 40a (see Figure 4). The incoming air flows into the cylindrical member 54. As shown in Figure 7, the incoming air is pushed out by the fan 44, rectified by multiple rectifier fins 55, and then flows along the cone 52. Since at least a portion of the lower surface of the case 57 blocks the opening 54a of the cylindrical member 54, the air pushed out by the fan 44 flows along the lower surface of the case 57. This cools the case 57, and as a result, the control unit 20 (control board 56) is cooled. The air then flows inside the discharge pipe 10 shown in Figure 8, through the diffusion cover 70, and is released to the outside of the work machine 2. The air is guided radially outward from the tip tube 66 by the diffusion fins 70a of the diffusion cover 70 and released over a wide area.

[0043] As shown in Figures 3 and 4, the battery unit 22 is located above the fan unit 18 and the control unit 20. The battery unit 22 includes a right-side battery mounting section 84, a left-side battery mounting section 86, and a plurality (two in this embodiment) of battery packs BP. The right-side battery mounting section 84 and the left-side battery mounting section 86 are aligned in the left-right direction. A central wall 88 is located in the second internal space 38, with the right-side battery mounting section 84 located on the right side of the central wall 88 and the left-side battery mounting section 86 located on the left side of the central wall 88. The central wall 88 is located in the left-right center of the second internal space 38. The central wall 88 is located on a plane that aligns with the vertical and front-back directions.

[0044] The battery pack BP is detachable from the right battery mounting section 84 and the left battery mounting section 86 when the cover section 34 is open. By sliding the battery pack BP in the front-to-back direction, the battery pack BP can be attached to and detached from the right battery mounting section 84 and the left battery mounting section 86. The battery pack BP is equipped with, for example, a lithium-ion battery. Power from the battery pack BP can be supplied to the electric motor 46 (see Figure 7). When the battery pack BP is attached to both the right battery mounting section 84 and the left battery mounting section 86, power is initially supplied to the electric motor 46 from one of the battery packs BP, in this embodiment, the right battery pack BP located on the discharge pipe 10 side. When the remaining power in the right battery pack BP reaches zero, power is supplied to the electric motor 46 from the left battery pack BP. In this state, when the right-side battery pack BP, whose remaining power is zero, is removed from the right-side battery mounting section 84, the center of gravity positions G6 and G7 (see Figure 6) of the main unit 4 move away from the discharge pipe 10 (to the left). This prevents the work implement 2 from tilting towards the discharge pipe 10 when it is being carried on the user's back.

[0045] The liquid tank 24 is located above the battery unit 22. As shown in Figure 9, the liquid tank 24 comprises a tank body 90, a protrusion 92, a filter unit 94, and a tank cap 96. The tank body 90 stores liquid for discharge (spraying). The capacity of the tank body 90 is, for example, 10L or more, and in this embodiment, it is 15L. The tank body 90 has a facing surface 90a that faces the user's back when the work machine 2 is carried on the user's back. The facing surface 90a constitutes part of the facing surface 4a of the main unit 4 (see Figure 2).

[0046] A first engagement groove 98 and a second engagement groove 100 are formed near the lower right end of the tank body 90. The first engagement groove 98 and the second engagement groove 100 are recessed toward the inside of the tank body 90. As shown in Figure 10, a third engagement groove 102 and a fourth engagement groove 104 are formed near the lower left end of the tank body 90. The third engagement groove 102 and the fourth engagement groove 104 are recessed toward the inside of the tank body 90. The main body housing 16 has a first engagement wall 106, a second engagement wall 108, a third engagement wall 110, and a fourth engagement wall 112. When the tank body 90 is sandwiched between the front body housing 26 and the rear body housing 28, the first engaging wall 106 engages with the first engaging groove 98, the second engaging wall 108 engages with the second engaging groove 100, the third engaging wall 110 engages with the third engaging groove 102, and the fourth engaging wall 112 engages with the fourth engaging groove 104. As a result, the lower part of the tank body 90 is fixed to the body housing 16 inside the body housing 16. As shown in Figure 1, when the tank body 90 is fixed to the body housing 16, the upper part of the tank body 90 is positioned above the body housing 16.

[0047] As shown in Figure 11, a discharge section 90b and a supply section 90c are formed at the lower end of the tank body 90. A discharge tube 91 is connected to the discharge section 90b. The discharge tube 91 is made of, for example, a resin material. Normally, a discharge cock 91a on the discharge tube 91 is closed. By opening the discharge cock 91a, the user can discharge the liquid stored in the tank body 90 to the outside of the liquid tank 24 through the discharge section 90b and the discharge tube 91. A supply line 113 is connected to the supply section 90c. The supply line 113 will be described in detail later.

[0048] As shown in Figure 9, the projection 92 is connected to the upper surface (top) of the tank body 90. When the work machine 2 is placed on the mounting surface P (see Figure 2), the projection 92 is positioned above the upper surface of the tank body 90. The projection 92 has a side wall 114 that is substantially cylindrical in shape. The side wall 114 defines a supply port 116. The supply port 116 is defined by the inner surface of the side wall 114. In other words, the supply port 116 is formed by the projection 92, and the projection 92 is composed of the side wall 114. The supply port 116 is an opening for supplying liquid into the tank body 90. Multiple ribs 118 are formed on the inner surface of the side wall 114. The multiple ribs 118 extend radially inward from the side wall 114.

[0049] The side wall 114 comprises a first side portion 120 and a second side portion 122. The first side portion 120 has a substantially cylindrical shape. The first side portion 120 includes an engaging rail 124 positioned on the outer surface of the first side portion 120. The engaging rail 124 extends spirally along the circumferential direction of the outer surface of the first side portion 120. The engaging rail 124 is partially interrupted in the circumferential direction of the outer surface of the first side portion 120.

[0050] The second side portion 122 is connected to the first side portion 120. The outer surface of the second side portion 122 has a planar shape. In a modified example, the outer surface of the second side portion 122 may have a curved shape. No engaging rail 124 is formed on the outer surface of the second side portion 122 in the circumferential direction of the side wall 114. As shown in Figure 12, the outer surface of the second side portion 122 is recessed radially inward from the side wall 114 compared to the outer surface of the first side portion 120. The outer surfaces of the second side portion 122 and the first side portion 120 are separated from the inner surface of the tank cap 96. The distance between the outer surface of the second side portion 122 and the inner surface of the tank cap 96 is greater than the distance between the outer surface of the first side portion 120 and the inner surface of the tank cap 96.

[0051] As shown in Figure 9, the second side portion 122 has a plurality of (six in this embodiment) communication holes 126. The plurality of communication holes 126 penetrate the second side portion 122 in the thickness direction.

[0052] The filter unit 94 comprises a base member 128, a filter 130, fins 132, and a handle 133. The base member 128 comprises a first cylindrical portion 134 having a substantially cylindrical shape and a second cylindrical portion 136 having a substantially cylindrical shape and a larger diameter than the first cylindrical portion 134. The first cylindrical portion 134 supports the filter 130. The filter 130 is positioned at the lower end opening of the first cylindrical portion 134. The filter 130 captures foreign matter, such as sand, contained in the liquid when supplying liquid into the tank body 90. The second cylindrical portion 136 is connected to the upper end of the first cylindrical portion 134. As shown in Figure 13, when the filter unit 94 is attached to the projection 92, the lower end of the second cylindrical portion 136 rests on a plurality of ribs 118.

[0053] As shown in Figure 9, the fins 132 are connected to the lower end of the first cylindrical section 134. The handle 133 is connected to the first cylindrical section 134. When the user grips the handle 133 and rotates the filter unit 94, the fins 132 rotate, agitating the liquid inside the tank body 90.

[0054] The tank cap 96 can close the supply port 116 of the side wall 114 from above. The tank cap 96 has a substantially cylindrical shape with a bottom wall at its upper end. As shown in Figure 13, the tank cap 96 is equipped with an engagement rail 140 positioned on the inner surface of the tank cap 96. The engagement rail 140 extends spirally along the circumferential direction of the inner surface of the tank cap 96. When the tank cap 96 is closing the supply port 116 of the side wall 114, the engagement rail 140 engages with the engaged rail 124.

[0055] As shown in Figure 14, when the engaging rail 140 engages with the engaged rail 124 and the tank cap 96 closes the supply port 116, the tank cap 96 covers the multiple communication holes 126. Even in this state, the multiple communication holes 126 communicate between the inside of the liquid tank 24 and the outside of the work machine 2. In addition, a communication space 142 is defined between the tank cap 96 and the side wall 114. The width of the communication space 142, that is, the distance between the inner surface of the tank cap 96 and the outer surface of the side wall 114, is greatest in the circumferential direction of the side wall 114 between the outer surface of the second side portion 122 and the inner surface of the tank cap 96. The communication space 142 communicates directly with the multiple communication holes 126. At its lower end, the communication space 142 communicates directly with the outside of the work machine 2.

[0056] The liquid tank 24 further comprises a one-way valve 144. The one-way valve 144 is attached to the second side portion 122. The one-way valve 144 is, for example, an umbrella valve. The one-way valve 144 is made of, for example, an elastic material, in this embodiment, a rubber material. The one-way valve 144 comprises a fixed portion 146 and a valve portion 148. The fixed portion 146 is inserted into and fixed to the second side portion 122. The valve portion 148 is connected to one end of the fixed portion 146. The valve portion 148 has, for example, a disc shape. The valve portion 148 is elastically deformable. The valve portion 148 is located inside the liquid tank 24 between the second side portion 122 and the base member 128. The valve portion 148 can contact the inner surface of the second side portion 122. The valve portion 148, by contacting the inner surface of the second side portion 122, prevents fluid (e.g., air and / or liquid) from flowing from the inside of the liquid tank 24 to the outside of the work machine 2 through the multiple communication holes 126. The valve portion 148, by moving away from the inner surface of the second side portion 122, allows fluid to flow from the outside of the work machine 2 to the inside of the liquid tank 24 through the multiple communication holes 126.

[0057] Normally, for example, when the work machine 2 is not in operation, the valve portion 148 is in contact with the inner surface of the second side portion 122. As a result, the multiple communication holes 126 are blocked, and the inside of the liquid tank 24 is not in communication with the outside of the work machine 2 through the multiple communication holes 126. When the work machine 2 is in operation, for example, when the work machine 2 is used to spray liquid from the discharge pipe 10 (see Figure 1) or when the liquid in the liquid tank 24 is discharged to the outside of the liquid tank 24 via the discharge portion 90b and discharge tube 91, the amount of liquid in the tank body 90 decreases. As a result, the volume of the void inside the liquid tank 24 increases. Since the inside of the liquid tank 24 is not in communication with the outside of the work machine 2, the pressure in the void inside the liquid tank 24 decreases. As shown in Figure 15, when the pressure in the void inside the liquid tank 24 becomes lower than the pressure outside the work machine 2 (atmospheric pressure), the valve portion 148 moves away from the inner surface of the second side portion 122 by elastic deformation. As a result, outside air from the work machine 2 flows into the communication space 142 from below the tank cap 96, as shown as airflow AF in Figure 15, passes through the communication space 142 and the multiple communication holes 126, and flows into the inside of the liquid tank 24. This increases the pressure in the void inside the liquid tank 24. This prevents situations where a decrease in the pressure in the void inside the liquid tank 24 makes it difficult for the liquid inside the liquid tank 24 to be supplied to the discharge pipe 10, or where the liquid inside the liquid tank 24 is difficult to discharge to the outside of the liquid tank 24 via the discharge section 90b and discharge tube 91.

[0058] The frame unit 6 shown in Figure 16 is fixed to the main unit 4 (see Figure 1). The frame unit 6 comprises a pair of side frames 170 and 172, a rear frame 174, a top frame 176, a lower frame 178, a first fixed frame 180, and a second fixed frame 182. Hereafter, the pair of side frames 170 and 172 may be referred to as the right side frame 170 and the left side frame 172. Each frame 170, 172, 174, 176, 178, 180, and 182 is made of a metal material, such as aluminum. Furthermore, each frame 170, 172, 174, 176, 178, 180, and 182 is elastically deformable by the external force acting on it.

[0059] The right side frame 170 comprises a first right side frame 170a extending in the front-rear direction, a second right side frame 170b extending downward from the front end of the first right side frame 170a, and a third right side frame 170c extending rearward from the lower end of the second right side frame 170b. A first contact member 184 is attached to the connection point between the second right side frame 170b and the third right side frame 170c. The first contact member 184 is made of a resin material, such as polycarbonate.

[0060] The left side frame 172 is positioned to the left of the right side frame 170. The left side frame 172 comprises a first left side frame 172a extending in the front-rear direction, a second left side frame 172b extending downward from the front end of the first left side frame 172a, and a third left side frame 172c extending rearward from the lower end of the second left side frame 172b. A second contact member 186 is attached to the connection point between the second left side frame 172b and the third left side frame 172c. The second contact member 186 is made of a resin material, such as polycarbonate. The second contact member 186 has a shape similar to that of the first contact member 184.

[0061] The rear frame 174 is connected to the rear end of the third right side frame 170c and the rear end of the third left side frame 172c. The rear frame 174 is integrally formed with the pair of side frames 170 and 172. The rear frame 174 extends in the left-right direction. A third contact member 188 is attached to the connection point between the rear frame 174 and the third right side frame 170c. A fourth contact member 190 is attached to the connection point between the rear frame 174 and the third left side frame 172c. The third contact member 188 and the fourth contact member 190 are made of a resin material, for example, polypropylene. As shown in Figure 2, when the work machine 2 is placed on the mounting surface P, only the first contact member 184, the second contact member 186, the third contact member 188, and the fourth contact member 190 are in contact with the mounting surface P.

[0062] As shown in Figure 16, the top frame 176 is connected to the first right side frame 170a and the first left side frame 172a by screws. The top frame 176 extends rearward from the rear end of the first right side frame 170a, then bends to the left, and then bends forward to the rear end of the first left side frame 172a.

[0063] The lower frame 178 is connected to the third right side frame 170c and the third left side frame 172c. The lower frame 178 is positioned between the third right side frame 170c and the third left side frame 172c. The lower frame 178 is positioned in front of the rear frame 174. The lower frame 178 extends in the left-right direction.

[0064] The first fixed frame 180 is connected to the second right side frame 170b and the second left side frame 172b. The first fixed frame 180 extends in the left-right direction. The second fixed frame 182 is connected to the second right side frame 170b and the second left side frame 172b below the first fixed frame 180. The second fixed frame 182 extends in the left-right direction.

[0065] As shown in Figure 17, a first fixing groove 192 and a second fixing groove 194 are formed on the opposing surface 30 of the main housing 16. The first fixing groove 192 and the second fixing groove 194 are recessed toward the rear from the opposing surface 30. The first fixing groove 192 extends in the left-right direction near the upper end of the opposing surface 30. The second fixing groove 194 extends in the left-right direction near the lower end of the opposing surface 30. As shown in Figure 18, the first fixing frame 180 is received in the first fixing groove 192 and fixed to the main housing 16 by screws. The upper surface of the first fixing frame 180 abuts against the upper surface of the first fixing groove 192 of the main housing 16. Also, when the first fixing frame 180 is received in the first fixing groove 192, the entire first fixing frame 180 is positioned behind the opposing surface 30 in the front-rear direction. The second fixing frame 182 is received in the second fixing groove 194 and fixed to the main body housing 16 by screws. The upper surface of the second fixing frame 182 abuts against the upper surface of the second fixing groove 194 of the main body housing 16. Furthermore, when the second fixing frame 182 is received in the second fixing groove 194, the entire second fixing frame 182 is positioned behind the opposing surface 30 in the front-rear direction. This prevents the first fixing frame 180 and the second fixing frame 182 from coming into contact with the user's back when the user carries the work machine 2 on their back.

[0066] Furthermore, as shown in Figures 11, 13, and 18, a receiving groove 196 is formed in the lower part of the tank body 90. The receiving groove 196 extends from the front right end of the tank body 90 toward the rear, then bends to extend to the left from the right end to the left end of the tank body 90, and then bends again to extend forward to the front left end of the tank body 90. The first right side frame 170a, the first left side frame 172a, and the top frame 176 are received in the receiving groove 196 and support the upper part of the tank body 90 from below.

[0067] The positional relationship between the main unit 4 and the frame unit 6 when the frame unit 6 is fixed to the main unit 4 will now be explained. As shown in Figure 19, in the left-right direction, the second right side frame 170b is positioned to the right (outside) of the main housing 16. The second left side frame 172b is positioned to the left (outside) of the main housing 16. That is, the main housing 16 is positioned between the second right side frame 170b and the second left side frame 172b. Therefore, the battery unit 22 (see Figure 3) and the fan unit 18 (see Figure 3), for example, the battery pack BP (see Figure 3) and the electric motor 46 (see Figure 7), are positioned between the second right side frame 170b and the second left side frame 172b.

[0068] In the vertical direction, the top frame 176 is positioned above (outside) the main housing 16. The rear frame 174 is positioned below (outside) the main housing 16. That is, the main housing 16 is positioned between the top frame 176 and the rear frame 174. For this reason, the battery unit 22 and the fan unit 18, for example, the battery pack BP and the electric motor 46, are also positioned between the top frame 176 and the rear frame 174.

[0069] As shown in Figure 5, in the front-to-back direction, the rear frame 174 is positioned behind (outside of) the main housing 16. Therefore, the rear frame 174 is positioned behind the battery unit 22 and the fan unit 18, for example, the battery pack BP and the electric motor 46.

[0070] As shown in Figure 20, the lower frame 178 is positioned below (outside) the main housing 16. The lower frame 178 faces the lower opposing surface 200 of the main housing 16. The lower opposing surface 200 constitutes the lower surface of the main housing 16. The lower opposing surface 200 has a curved shape that is convex downward toward the lower frame 178. In the left-right direction, the central part of the lower opposing surface 200 is positioned closest to the lower frame 178, and both ends of the lower opposing surface 200 are positioned furthest from the lower frame 178.

[0071] When the work machine 2 falls and collides with the mounting surface P from its lower end, at least one of the contact members 184, 186, 188, and 190 collides with the mounting surface P first. As a result, the third right side frame 170c (see Figure 16) and / or the third left side frame 172c (see Figure 16) and / or the rear frame 174 (see Figure 16) undergo elastic deformation before the main housing 16 collides with the mounting surface P. Subsequently, the lower frame 178 comes into contact with the lower opposing surface 200 and elastically deforms to conform to the shape of the lower opposing surface 200. As a result, the impact from the fall is absorbed by the lower frame 178, and damage to the main housing 16 is suppressed.

[0072] As shown in Figure 18, the harness unit 8 is attached to the main unit 4. The harness unit 8 comprises a pad 204, a waist belt 206, and a shoulder harness unit 208. The pad 204 is fixed to the opposing surface 30 of the main housing 16. The pad 204 is positioned opposite the first fixing groove 192 of the main housing 16. The pad 204 comes into contact with the user's back when the user carries the work machine 2 on their back. The waist belt 206 is positioned below the pad 204. The waist belt 206 is positioned opposite the second fixing groove 194 of the main housing 16. The waist belt 206 is worn around the user's waist when the user carries the work machine 2 on their back.

[0073] The shoulder harness unit 208 includes a right shoulder harness 210 that is worn on the user's right shoulder and a left shoulder harness 212 that is worn on the user's left shoulder. A first upper mounting portion 214 is formed on the opposing surface 90a of the tank body 90, and the right shoulder harness 210 is attached to the first upper mounting portion 214. The right shoulder harness 210 is directly attached to the tank body 90. A first lower mounting portion 216 is formed at the right end of the second fixing frame 182, and the right shoulder harness 210 is also attached to the first lower mounting portion 216. The first lower mounting portion 216 is located below the first upper mounting portion 214. The right shoulder harness 210 is attached to the main body housing 16 via the second fixing frame 182.

[0074] A second upper mounting portion 218 is formed on the opposing surface 90a of the tank body 90, and the left shoulder harness 212 is attached to the second upper mounting portion 218. The left shoulder harness 212 is directly attached to the tank body 90. A second lower mounting portion 220 is formed at the left end of the second fixing frame 182, and the left shoulder harness 212 is also attached to the second lower mounting portion 220. The second lower mounting portion 220 is located below the second upper mounting portion 218. The left shoulder harness 212 is attached to the main body housing 16 via the second fixing frame 182.

[0075] As shown in Figure 21, in the left-right direction, the center position CP3 between the first upper mounting portion 214 and the second upper mounting portion 218 is located on the discharge pipe 10 side (right side) than the center position CP2 of the main unit 4. The center position CP3 is located at the center between the geometric center of the first upper mounting portion 214 and the geometric center of the second upper mounting portion 218. That is, the left-right distance from the center position CP3 to the left end of the first upper mounting portion 214 is approximately equal to the left-right distance from the center position CP3 to the right end of the second upper mounting portion 218. In Figure 21, the center position CP2 is shown by a dashed line, and the center position CP3 is shown by a dotted line. In the left-right direction, the center position CP2 is located between the first upper mounting portion 214 and the second upper mounting portion 218. When two battery packs BP (see Figure 3) are arranged in the second internal space 38 (see Figure 3) and the liquid tank 24 is filled to its maximum capacity, the center of gravity of the main unit 4 is at center of gravity position G6, and the center of gravity of the work implement 2 is at the first overall center of gravity position G8. When two battery packs BP are arranged in the second internal space 38 and the liquid tank 24 is empty, the center of gravity of the main unit 4 is at center of gravity position G7, and the center of gravity of the work implement 2 is at the second overall center of gravity position G9. With respect to the left-right direction, the center of gravity positions G6, G7, the first overall center of gravity position G8, and the second overall center of gravity position G9 are located between the first upper mounting part 214 and the second upper mounting part 218. The center of gravity positions G6, G7, the first overall center of gravity position G8, and the second overall center of gravity position G9 are located to the right of the discharge pipe 10 side of the center position CP2. The center of gravity position G6 and the first overall center of gravity position G8 are located on the opposite side (left side) from the discharge pipe 10 than the center position CP3. The first overall center of gravity position G8 is located closer to the center position CP3 than the center of gravity position G6. The center of gravity position G7 and the second overall center of gravity position G9 are located closer to the discharge pipe 10 (right side) than the center position CP3. The second overall center of gravity position G9 is located further away from the center of gravity position G7 than from the center position CP3. With respect to the left-right direction, the center position CP3 is located approximately in the center between the first overall center of gravity position G8 and the second overall center of gravity position G9.In other words, the lateral distance from the central position CP3 to the first overall center of gravity position G8 is approximately equal to the lateral distance from the central position CP3 to the second overall center of gravity position G9.

[0076] Next, the supply line 113 will be described. As shown in Figures 8 and 11, the supply line 113 comprises a first supply pipe 230, a first supply cock 232, a solenoid valve 234, a supply tube 236, a second supply cock 238, a second supply pipe 240, and a third supply cock 242. When the work machine 2 is operating, the first supply cock 232, the second supply cock 238, and the third supply cock 242 are open. As shown in Figure 11, the first supply pipe 230 is connected to the supply section 90c of the tank body 90. The first supply pipe 230 is made of metal. The first supply cock 232 and the solenoid valve 234 are located on the first supply pipe 230. The first supply cock 232 is operated by the user. The first supply cock 232 opens and closes the first supply pipe 230. Although not shown in the illustration, the solenoid valve 234 is located inside the main housing 16 (see Figure 3). The solenoid valve 234 is electrically connected to the control board 56 (see Figure 7). The solenoid valve 234 opens and closes under the control of the control board 56.

[0077] The supply tube 236 is connected to the first supply pipe 230. The supply tube 236 is made of, for example, a resin material. As shown in Figure 8, the supply tube 236 extends along the discharge pipe 10. The second supply cock 238 is located on the supply tube 236. The supply tube 236 is fixed to the discharge pipe 10 at the location where the second supply cock 238 is located. The second supply cock 238 is operated by the user. The second supply cock 238 opens and closes the supply tube 236.

[0078] As shown in Figure 22, the second supply pipe 240 is connected to the supply tube 236. The second supply pipe 240 is made of, for example, a resin material. The tip pipe 66 comprises a first tip pipe 67 and a second tip pipe 68 attached to the front end of the first tip pipe 67, and the second supply pipe 240 is integrally formed with the first tip pipe 67. The second supply pipe 240 comprises an outer portion 244, a first inner portion 246, and a second inner portion 248. The outer portion 244 is located outside the tip pipe 66. The third supply cock 242 is located on the outer portion 244. The third supply cock 242 is operated by the user. The third supply cock 242 opens and closes the outer portion 244. The first inner portion 246 and the second inner portion 248 are located inside the tip pipe 66. The first inner portion 246 extends downward from the lower end of the outer portion 244. The second inner portion 248 extends from the lower end of the first inner portion 246 toward the discharge opening 68a of the second end pipe 68. When the first supply cock 232 (see Figure 11), the solenoid valve 234 (see Figure 11), the second supply cock 238 (see Figure 8), and the third supply cock 242 are open, the liquid in the liquid tank 24 (see Figure 8) can flow through the first supply pipe 230 (see Figure 8), the supply tube 236, and the second supply pipe 240.

[0079] The following description will use the case where the longitudinal direction of the tip tube 66 is aligned with the front-to-back direction as an example. The work machine 2 further comprises a cylindrical member 250 and a liquid nozzle 252. The cylindrical member 250 is located inside the second tip tube 68. The cylindrical member 250 has a substantially cylindrical shape with its longitudinal direction in the front-to-back direction. The cylindrical member 250 comprises a front cylindrical portion 250a and a rear cylindrical portion 250b. The front cylindrical portion 250a is connected to the second tip tube 68 via a plurality of fins 254. The front cylindrical portion 250a, the plurality of fins 254, and the second tip tube 68 are integrally formed. The rear cylindrical portion 250b is located behind the front cylindrical portion 250a. The rear cylindrical portion 250b is connected to the fins 254 and the second tip tube 68 by screws. The inner diameter of the cylindrical member 250 decreases from the rear end to the front end, and then increases. A portion of the air flowing inside the tip tube 66 flows inside the cylindrical member 250 as indicated by arrow F1 in Figure 22, while the remaining air flowing inside the tip tube 66 flows outside the cylindrical member 250 as indicated by arrow F2 in Figure 22.

[0080] The liquid nozzle 252 is, for example, an ultra-low volume nozzle. The liquid nozzle 252 is located inside the second tip tube 68. The front end of the liquid nozzle 252 is located closest to the discharge opening 68a of the second tip tube 68 (at the forefront), and the rear end of the liquid nozzle 252 is located furthest from the discharge opening 68a of the second tip tube 68 (at the rear). The front end of the liquid nozzle 252 corresponds to the tip of the liquid nozzle 252, and the rear end of the liquid nozzle 252 corresponds to the base end of the liquid nozzle 252. The liquid nozzle 252 has a longitudinal direction in the front-rear direction. The liquid nozzle 252 is made of a metallic material, for example, brass. In a modified example, the liquid nozzle 252 may be made of a resin material. As shown in Figure 23, the liquid nozzle 252 comprises an insertion portion 256 and a nozzle portion 258. The insertion portion 256 has a substantially cylindrical shape. As shown in Figure 24, an elastic member 262 is attached to the outer surface of the insertion portion 256. The elastic member 262 is, for example, an O-ring. A male threaded portion 264 is formed on the outer surface of the insertion portion 256. A female threaded portion 248a is formed on the inner surface of the second inner portion 248. By inserting the insertion portion 256 into the inner surface of the second inner portion 248 and screwing the male threaded portion 264 of the insertion portion 256 into the female threaded portion 248a of the second inner portion 248, the insertion portion 256 is connected to the second inner portion 248. When the insertion portion 256 is connected to the second inner portion 248, the elastic member 262 is sandwiched between the outer surface of the insertion portion 256 and the inner surface of the second inner portion 248. This seals the space between the outer surface of the insertion portion 256 and the inner surface of the second inner portion 248.

[0081] The nozzle portion 258 is connected to the front end of the insertion portion 256. The nozzle portion 258 has a side surface 266. The side surface 266 forms at least a portion of the outer shape of the nozzle portion 258. A portion of the air flowing inside the tip tube 66 (see Figure 22) flows along the side surface 266 toward the front end (tip) of the liquid nozzle 252, as indicated by arrow F1. The side surface 266 comprises a first side surface 268 and a second side surface 270. The diameter of the rear end of the first side surface 268 is approximately equal to the diameter of the outer surface of the second inner portion 248. The diameter of the first side surface 268 decreases from the rear end to the front end of the nozzle portion 258. The first side surface 268 has a smooth curved shape. The second side surface 270 is located in front of the first side surface 268. The diameter of the second side surface 270 is equal to the diameter of the front end of the first side surface 268 and is constant in the front-rear direction. As shown in Figure 22, at least a portion of the first side surface 268 and the second side surface 270 are surrounded by the rear cylindrical portion 250b.

[0082] As shown in Figure 24, the liquid nozzle 252 further comprises a liquid passage 274. The liquid passage 274 is located inside the insertion section 256 and the nozzle section 258. The liquid passage 274 extends from the rear end (base) to the front end (tip) of the liquid nozzle 252. The liquid passage 274 is located on the central axis CX of the liquid nozzle 252. In Figures 24 and 25, the central axis CX is shown by a dashed line. The central axis CX extends in the front-rear direction (longitudinal direction of the liquid nozzle 252). The liquid passage 274 comprises a main passage 276, a transition passage 278, and a throttling passage 280. The diameter of the main passage 276 is, for example, 5 mm. The main passage 276 extends from the rear end of the insertion section 256 toward the front. The main passage 276 is located across the insertion section 256 and the nozzle section 258. As shown in Figure 25, the transition passage 278 is connected to the main passage 276. The diameter of the transition passage 278 gradually decreases towards the front. The diameter of the aperture passage 280 is smaller than the diameter of the main passage 276. The diameter of the aperture passage 280 is, for example, 0.5 mm. The aperture passage 280 extends from the front end of the transition passage 278 to the tip surface 282 of the nozzle section 258.

[0083] The tip surface 282 of the nozzle portion 258 corresponds to the tip surface of the liquid nozzle 252. The tip surface 282 comprises an inclined surface 284 and a non-inclined surface 286. The discharge port 280a of the throttling passage 280 is located on the inclined surface 284. The discharge port 280a is located at the center of the inclined surface 284. The center of the inclined surface 284 is located on the central axis CX. When a plane perpendicular to the central axis CX is taken as a virtual plane VP1, the inclined surface 284 is inclined with respect to the virtual plane VP1. In Figure 25, the virtual plane VP1 is shown by a dashed line. The inclination angle of the inclined surface 284 with respect to the virtual plane VP1 is, for example, 5 degrees or more, and in this embodiment, it is 20 degrees. The front end of the inclined surface 284 is located in front of the rear end of the inclined surface 284 (towards the tip of the liquid nozzle 252). The front end of the inclined surface 284 is further from the central axis CX than the rear end of the inclined surface 284. In other words, the inclined surface 284 moves away from the central axis CX as it moves towards the front side (towards the tip of the liquid nozzle 252).

[0084] The non-inclined surface 286 is positioned around the entire periphery of the inclined surface 284. The non-inclined surface 286 is positioned in front of the inclined surface 284. The non-inclined surface 286 is further from the central axis CX than the inclined surface 284. The non-inclined surface 286 is approximately parallel to the virtual surface VP1. The non-inclined surface 286 is inclined with respect to the inclined surface 284. Also, the non-inclined surface 286 is approximately perpendicular to the second side surface 270.

[0085] The liquid nozzle 252 further comprises a corner 290. The corner 290 is further away from the central axis CX than the non-inclined surface 286. As shown in Figure 26, the corner 290 connects the second side surface 270 and the non-inclined surface 286. Figure 26 is an enlarged cross-sectional view of the corner 290 of the liquid nozzle 252, exaggerating its appearance. The corner 290 is positioned around the entire circumference of the periphery of the non-inclined surface 286. The corner 290 constitutes the corner of the front end (tip) of the liquid nozzle 252. The radius of curvature of the corner 290 is, for example, 0.3 mm or less. The corner 290 is a sharp corner (pin corner). The corner 290 may be acutely pointed or obtusely pointed. The corner 290 has a curved shape. In a modified example, the corner 290 may have a planar shape. The corner portion 290 is connected to the second side portion 270 at the side connection point 292 and to the non-inclined surface 286 at the tip connection point 294. Near the corner portion 290, a virtual side portion 296, which is an extension of the second side portion 270, and a virtual tip surface 298, which is an extension of the non-inclined surface 286, intersect at approximately a right angle at the first location 300. The distance L1 between the first location 300 and the side connection point 292 is, for example, 0.3 mm or less. Also, the distance L2 between the first location 300 and the tip connection point 294 is, for example, 0.3 mm or less. Distance L2 is approximately equal to distance L1. In modified examples, distance L2 may be different from distance L1.

[0086] Next, the manufacturing method for the liquid nozzle 252 will be described. The manufacturing method comprises an insertion portion cutting step, a tip surface cutting step, a side cutting step, and a liquid flow path formation step. As shown in Figure 24, in the insertion portion cutting step, the cutting blade is moved from the rear end (base end) to the front end (tip) of the liquid nozzle 252 to form an insertion portion 256 on the liquid nozzle 252. The cutting blade is also moved spirally in the circumferential direction of the outer surface of the insertion portion 256 to form a male thread portion 264 on the insertion portion 256. Next, as shown in Figure 26, in the tip surface cutting step, at the front end (tip) of the liquid nozzle 252, the cutting blade is moved away from the central axis CX (in the first direction D1 in Figure 26), starting from the central axis CX, to form a tip surface 282 on the liquid nozzle 252. Next, in the side cutting process, the cutting blade is moved from the insertion portion 256 toward the tip surface 282 (in the second direction D2 in Figure 26) on the side of the liquid nozzle 252 to form a side surface 266 on the liquid nozzle 252. This forms a sharp corner portion 290 at the front end (tip) of the liquid nozzle 252. At this time, minute protrusions (burrs) not shown are formed on the corner portion 290, and these protrusions are positioned closer to the central axis CX than the second side surface 270 and extend toward the front. That is, the protrusions do not protrude away from the central axis CX than the second side surface 270. Finally, as shown in Figure 24, in the liquid flow path formation process, a drilling machine is inserted into the liquid nozzle 252 to form a liquid passage 274 in the liquid nozzle 252.

[0087] Next, we will explain the behavior of the liquid being atomized after being discharged from the liquid nozzle 252. First, as shown in Figure 22, when the fan 44 (see Figure 7) rotates due to the rotation of the electric motor 46 (see Figure 7), air flows into the discharge pipe 10. After the air flows through the discharge pipe 10 to the tip pipe 66, it flows into the inside of the cylindrical member 250 as shown by arrow F1 in Figure 22, and flows along the side surface 266 of the liquid nozzle 252 toward the front end (tip) of the liquid nozzle 252. In addition, the first side surface 268 of the liquid nozzle 252 is surrounded by the cylindrical member 250, and the diameter of the first side surface 268 decreases as it moves from the rear end to the front end of the nozzle portion 258. As a result, air flows more easily into the inside of the cylindrical member 250, and the airflow velocity is increased as the space through which the air flows (the space around the first side surface 268) narrows. The air flowing along the side surface 266 passes through the liquid nozzle 252 and flows inside the cylindrical member 250 from the rear end to the front end. As shown in Figure 25, this airflow creates a pressure difference between the region near the side surface 266 and the front region of the tip surface 282 of the liquid nozzle 252. As a result, the airflow (vortex flow) SW1 shown in Figure 25 is generated in the front region of the tip surface 282 of the liquid nozzle 252. First, the airflow SW1 flows along the central axis CX towards the tip surface 282 of the liquid nozzle 252. Next, the airflow SW1 curves away from the central axis CX and flows over the tip surface 282 towards the corner 290, in the order of the inclined surface 284 and the non-inclined surface 286. Finally, the airflow SW1 merges with the airflow flowing along the side surface 266 near the corner 290.

[0088] As the airflow SW1 flows along the tip surface 282 toward the corner 290, the liquid discharged from the outlet 280a of the throttling passage 280 to the outside of the liquid nozzle 252 flows along the tip surface 282 toward the corner 290, in the order of the inclined surface 284 and the non-inclined surface 286. Due to the generation of this airflow SW1, the liquid is discharged from the outlet 280a to the outside of the liquid nozzle 252 without the use of a drive source such as a pump.

[0089] The liquid that has flowed to the corner 290 moves toward the side surface 266. Because the corner 290 is a sharp corner, the liquid is less likely to form a pool on the corner 290 and moves smoothly from the corner 290 toward the side surface 266. As a result, when the liquid collides with the air flowing along the side surface 266, the liquid is atomized. The liquid is atomized to a diameter of, for example, 50 micrometers or less. With the configuration of the liquid nozzle 252 in this embodiment, the electric motor 46-driven (electric) work machine 2 of this embodiment can atomize the liquid even though the airflow of the fan 44 is lower than that of an engine-driven work machine.

[0090] As shown in Figure 22, the atomized liquid flows through the tip tube 66 together with the air flowing inside the cylindrical member 250 indicated by arrow F1. Subsequently, the liquid and air flowing inside the cylindrical member 250 merge with the air flowing outside the cylindrical member 250 indicated by arrow F2, and are released (sprayed) from the diffusion cover 70 to the outside of the second tip tube 68.

[0091] (effect) The work machine 2 of this embodiment discharges liquid. The work machine 2 comprises a discharge pipe 10 for discharging liquid and a liquid tank 24. The liquid tank 24 has a tank body 90 for storing liquid, a supply port 116 for supplying liquid to the tank body 90, and a communication hole 126. It also comprises a projection 92 positioned on the upper part of the tank body 90 when the work machine 2 is placed on the mounting surface P, a tank cap 96 (an example of a cap) that engages with the projection 92 and closes the supply port 116, and a one-way valve 144 attached to the projection 92. When the tank cap 96 is engaged with the projection 92 and closing the supply port 116, the communication hole 126 connects the inside of the liquid tank 24 to the outside of the work machine 2. The one-way valve 144 is configured to prohibit the flow of fluid from the inside of the liquid tank 24 to the outside of the work machine 2 through the communication hole 126, and to allow the flow of fluid from the outside of the work machine 2 to the inside of the liquid tank 24 through the communication hole 126.

[0092] According to the above configuration, even when the tank cap 96 is engaged with the protrusion 92 and blocking the supply port 116, when the one-way valve 144 is opened, the inside of the liquid tank 24 and the outside of the work machine 2 are in communication through the communication hole 126. Even if the amount of liquid stored in the liquid tank 24 decreases, the flow of fluid, such as air, into the liquid tank 24 through the communication hole 126 can suppress a decrease in the pressure of the void inside the liquid tank 24. This can suppress the difficulty in supplying liquid towards the discharge pipe 10.

[0093] Furthermore, the protruding portion 92 is provided with a side wall 114 that defines the supply port 116. The communication hole 126 is located in the side wall 114.

[0094] According to the above configuration, the structure of the protruding portion 92 does not become complicated, and it is possible to suppress the difficulty in supplying liquid towards the discharge pipe 10.

[0095] Furthermore, the tank cap 96 is equipped with a spirally extending engagement rail 140. The side wall 114 comprises a first side portion 120 having an engagement rail 124 that engages with the engagement rail 140 and extends along the circumferential direction of the outer surface of the side wall 114, and a second side portion 122 on which the engagement rail 124 is not formed in the circumferential direction of the outer surface of the side wall 114. The communication hole 126 is located in the second side portion 122.

[0096] According to the above configuration, the side wall 114 is divided into an area where the engaged rail 124 is located and an area where the communication hole 126 is located. The engagement of the engaged rail 124 and the engaging rail 140 makes it possible to prevent the inside of the liquid tank 24 and the outside of the work machine 2 from becoming difficult to communicate through the communication hole 126.

[0097] Furthermore, the second side portion 122 is recessed radially inward compared to the first side portion 120.

[0098] According to the above configuration, even if the tank cap 96 engages with the protrusion 92, the outer surface of the second side portion 122 does not come into contact with the tank cap 96. This makes it possible to prevent the inside of the liquid tank 24 and the outside of the work machine 2 from becoming difficult to communicate through the communication hole 126.

[0099] Furthermore, the one-way valve 144 is located inside the liquid tank 24 and includes a valve section 148 capable of blocking the communication hole 126.

[0100] According to the above configuration, it is possible to prevent foreign matter, such as sand, from adhering to the valve section 148 from being outside the liquid tank 24. This prevents the one-way valve 144 from becoming difficult to open and close due to sand or other foreign matter.

[0101] Furthermore, the liquid tank 24 can be attached to the supply port 116 of the protrusion 92 and is equipped with a filter unit 94 that captures foreign matter contained in the liquid when supplying liquid to the tank body 90. The valve 148 is located between the filter unit 94 and the side wall 114.

[0102] According to the above configuration, it is possible to suppress the adhesion of foreign matter contained in the liquid, such as sand, to the valve portion 148. This prevents the one-way valve 144 from becoming difficult to open and close due to sand or other foreign matter.

[0103] Furthermore, when the tank cap 96 engages with the protrusion 92 and closes the supply port 116, the communication hole 126 is covered by the tank cap 96.

[0104] According to the above configuration, it is possible to prevent sand or other materials outside the liquid tank 24 from blocking the communication hole 126.

[0105] Furthermore, when the tank cap 96 engages with the projection 92 and closes the supply port 116, a communication space 142 is defined between the tank cap 96 and the projection 92. The communication hole 126 connects the inside of the liquid tank 24 to the communication space 142. At its lower end, the communication space 142 is in communication with the outside of the work machine 2.

[0106] With the above configuration, sand and other debris outside the liquid tank 24 are less likely to enter the communication space 142. This further suppresses the blockage of the communication hole 126 by sand and other debris.

[0107] Furthermore, the one-way valve 144 is an umbrella valve.

[0108] With the above configuration, the one-way valve 144 can be opened with a relatively weak force.

[0109] (modified version) The work machine 2 according to one embodiment may be an engine-powered work machine.

[0110] The work machine 2 according to one embodiment is not limited to a mist blower, but may be, for example, a sprayer or a high-pressure washer.

[0111] In one embodiment, the work machine 2 may be a work machine equipped with a built-in battery. In this case, the built-in battery is charged by connecting the power cord to an external power source.

[0112] In one embodiment, the battery unit 22 may comprise only one battery pack BP.

[0113] The work machine 2 according to one embodiment is not limited to a backpack-type work machine, but may also be a stationary work machine or a handheld work machine, for example.

[0114] The one-way valve 144 according to one embodiment is not limited to an umbrella valve, but may be, for example, a duckbill valve.

[0115] In one embodiment, the liquid tank 24 may not be equipped with a filter unit 94.

[0116] In one embodiment of the liquid tank 24, the side wall 114 does not necessarily have a second side portion 122. In this case, the multiple communication holes 126 may be arranged in the first side portion 120 at locations where the engaged rail 124 is partially interrupted.

[0117] In one embodiment, the shoulder harness unit 208 does not have to be attached to the liquid tank 24. In this case, the shoulder harness unit 208 is attached only to the main body housing 16.

[0118] In the work machine 2 according to one embodiment, the vertical arrangement of the fan unit 18, the battery unit 22, and the liquid tank 24 is not limited to the configuration of this embodiment. For example, the fan unit 18 may be positioned above the battery unit 22, and the liquid tank 24 may be positioned above the fan unit 18.

[0119] As shown in Figure 27, in one embodiment of the liquid nozzle 252, a plurality of discharge ports 280a may be formed on the tip surface 282. The plurality of discharge ports 280a may be arranged, for example, around the central axis CX.

[0120] As shown in Figure 28, in one embodiment of the liquid nozzle 252, the tip surface 282 may further include a central non-inclined surface 310. The central non-inclined surface 310 is substantially parallel to the virtual surface VP1. The discharge port 280a of the throttling passage 280 is located on the central non-inclined surface 310. The inclined surface 284 is connected to the periphery of the central non-inclined surface 310.

[0121] In one embodiment of the liquid nozzle 252, the tip surface 282 does not necessarily have a non-inclined surface 286. In this case, the inclined surface 284 is connected to the corner portion 290.

[0122] In one embodiment of the liquid nozzle 252, the corner portion 290 may be located only on a portion of the circumferential edge of the tip surface 282. [Explanation of symbols]

[0123] 2: Work equipment 4: Main Unit 4a, 30, 90a: Opposing surfaces 6: Frame Unit 10: Release tube 16: Main housing 18: Fan Unit 20: Control Unit 22: Battery Unit 24: Liquid Tank 44: Fan 46: Electric motor 66: Tip tube 84: Right-side battery mounting area 86: Left side battery mounting area 90: Tank body 92:Protrusion 94: Filter Unit 96: Tank cap 114: Side wall 116: Supply port 120: First side 122: Second side 124: Engaged rail 126:Communication hole 140: Engaging Rail 142:Communication space 144: One-sided argument 148: Valve section 170: Light side frame 172: Left side frame 174: Rear frame 178: Lower frame 196: Receiving groove 200: Lower opposing surface 208: Shoulder Harness Unit 210: Right shoulder harness 212: Left shoulder harness 214: First upper mounting section 218: Second upper mounting section 250: Cylindrical member 252: Liquid nozzle 258: Nozzle part 266: Side view 268 :1st side 270:Second side 274:Liquid passage 280a: Outlet 282:Tip surface 284: Inclined surface 290: Corner 296: Virtual Aspect 298: Virtual tip surface BP: Battery Pack CP1, CP2, CP3: Center position CX: Central axis G1, G2, G3, G4, G5, G6, G7, G8, G9: Center of gravity position P: Mounting surface SW1: Airflow VP1: Virtual Surface

Claims

1. A work machine that discharges liquid, A discharge pipe for releasing the aforementioned liquid, It is equipped with a liquid tank, The aforementioned liquid tank is A tank body for storing the aforementioned liquid, The tank body has a supply port for supplying the liquid and a communication hole, and a protruding portion that is positioned on the upper part of the tank body when the work machine is placed on the mounting surface, A cap that engages with the aforementioned protrusion and closes the supply port, The system includes a one-way valve attached to the aforementioned protrusion, When the cap engages with the protrusion and closes the supply port, the communication hole connects the inside of the liquid tank and the outside of the work machine. The one-way valve is configured to prohibit the flow of fluid from the inside of the liquid tank to the outside of the work machine through the communication hole, and to allow the flow of fluid from the outside of the work machine to the inside of the liquid tank through the communication hole. The aforementioned protrusion is provided with a side wall that defines the supply port, The aforementioned communication hole is located in the side wall, The aforementioned cap is equipped with a spirally extending engagement rail, The aforementioned side wall is A rail to be engaged extends along the circumferential direction of the outer surface of the side wall, and comprises a first side portion having the rail to be engaged that engages with the engaging rail, The side wall comprises a second side portion on the outer surface of the side wall in which the engaging rail is not formed in the circumferential direction, The aforementioned communication hole is located on the second side, The second side portion is recessed radially inward compared to the first side portion of the work machine.

2. The work machine according to claim 1, wherein the one-way valve is located inside the liquid tank and has a valve portion capable of closing the communication hole.

3. The liquid tank is attachable to the supply port of the protruding portion and includes a filter unit that captures foreign matter contained in the liquid when the liquid is supplied to the tank body. The work machine according to claim 2, wherein the valve is disposed between the filter unit and the side wall.

4. The work machine according to claim 1, wherein when the cap engages with the protruding portion and closes the supply port, the communication hole is covered by the cap.

5. When the cap engages with the protrusion and closes the supply port, a communication space is defined between the cap and the protrusion. The aforementioned communication hole connects the interior of the liquid tank with the communication space. The work machine according to claim 4, wherein the communication space is in communication with the outside of the work machine at its lower end.

6. The work machine according to claim 1, wherein the one-way valve is an umbrella valve.

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